Science.gov

Sample records for activatable imaging probes

  1. An intracellularly activatable, fluorogenic probe for cancer imaging.

    PubMed

    Tian, Ruisong; Li, Mingjie; Wang, Jin; Yu, Min; Kong, Xiuqi; Feng, Yupeng; Chen, Zeming; Li, Yuxi; Huang, Weiqiang; Wu, Wenjie; Hong, Zhangyong

    2014-08-01

    A newly designed, dual-functional probe based on intracellular activation has been successfully developed for the detection of cancer cells. The probe is nearly non-fluorescent in buffer due to its highly efficient FRET quenching, but it can be specifically activated with dramatic fluorescence enhancement upon intracellular cathepsin B cleavage in target cancer cells after selective internalization via folate receptor-dependent endocytosis. Therefore, this probe enables "turn-on" visualization of cancer cells with desirable specificity and contrast enhancement. This targeted, intracellularly activatable probe exhibits low fluorescence-quenched background when compared with "always-on" probes and avoids non-specific activation by non-specifically expressed enzymes in normal tissue, which normally occurs when using common "turn on" probe design strategies. Therefore, this probe can be potentially applied in intraoperative inspection during clinical cancer surgery with higher contrast and sensitivity.

  2. Fluorescence imaging of tumors with "smart" pH-activatable targeted probes.

    PubMed

    Asanuma, Daisuke; Kobayashi, Hisataka; Nagano, Tetsuo; Urano, Yasuteru

    2009-01-01

    One goal of molecular imaging is to establish a widely applicable technique for specific detection of tumors with minimal background originated from non-target tissues. In this study, a "smart" activatable strategy for specific tumor imaging is proposed in which pH-activatable targeted probes specifically detect tumors after binding to the target cell surface proteins, internalization, and eventual acidic pH activation within the acidic organelles. We successfully visualized submillimeter-sized tumors using this strategy in two different tumor mouse models. Since the design of pH-activatable targeted probes can be applied to any target molecules on the cell surface that are to be internalized after ligand binding, this imaging strategy can afford a general and powerful method to diagnose and monitor the target tumors.

  3. Novel live imaging techniques of cellular functions and in vivo tumors based on precise design of small molecule-based 'activatable' fluorescence probes.

    PubMed

    Urano, Yasuteru

    2012-12-01

    Recently established rational design strategies for novel fluorescence probes, especially those based on photoinduced electron transfer and spirocyclization were reviewed. Based on these design strategies, various novel fluorescence probes were successfully developed including those for reactive oxygen species, reporter enzymes. Furthermore, in vivo cancer imaging techniques based on rationally designed activatable probes such as cancer-specific antibodies tagged with acidic-pH activatable fluorescence probes and peptidase activatable fluorescence probes were also discussed.

  4. Near-infrared pH-activatable fluorescent probes for imaging primary and metastatic breast tumors.

    PubMed

    Lee, Hyeran; Akers, Walter; Bhushan, Kumar; Bloch, Sharon; Sudlow, Gail; Tang, Rui; Achilefu, Samuel

    2011-04-20

    Highly tumor selective near-infrared (NIR) pH-activatable probe was developed by conjugating pH-sensitive cyanine dye to a cyclic arginine-glycine-aspartic acid (cRGD) peptide targeting α(v)β(3) integrin (ABIR), a protein that is highly overexpressed in endothelial cells during tumor angiogenesis. The NIR pH-sensitive dye used to construct the probe exhibits high spectral sensitivity with pH changes. It has negligible fluorescence above pH 6 but becomes highly fluorescent below pH 5, with a pK(a) of 4.7. This probe is ideal for imaging acidic cell organelles such as tumor lysosomes or late endosomes. Cell microscopy data demonstrate that binding of the cRGD probe to ABIR facilitated the endocytosis-mediated lysosomal accumulation and subsequent fluorescence enhancement of the NIR pH-activatable dye in tumor cells (MDA-MB-435 and 4T1/luc). A similar fluorescence enhancement mechanism was observed in vivo, where the tumors were evident within 4 h post injection. Moreover, lung metastases were also visualized in an orthotopic tumor mouse model using this probe, which was further confirmed by histologic analysis. These results demonstrate the potential of using the new integrin-targeted pH-sensitive probe for the detection of primary and metastatic cancer.

  5. Photo-click construction of a targetable and activatable two-photon probe imaging protease in apoptosis.

    PubMed

    Zhou, Mi; Hu, Jing; Zheng, Mengmeng; Song, Qinhua; Li, Jinbo; Zhang, Yan

    2016-02-01

    A photo-click reaction was used as an efficient method to construct two-photon fluorescent probes bearing two functional peptides for targeting and for protease cleavage respectively. The activatable two-photon probe constructed by this method was applied to two-photon imaging of caspase-3 both in cellular apoptosis and in tumor tissue.

  6. Minibody-indocyanine green based activatable optical imaging probes: the role of short polyethylene glycol linkers.

    PubMed

    Watanabe, Rira; Sato, Kazuhide; Hanaoka, Hirofumi; Harada, Toshiko; Nakajima, Takahito; Kim, Insook; Paik, Chang H; Wu, Anna M; Choyke, Peter L; Kobayashi, Hisataka

    2014-04-10

    Minibodies show rapider blood clearance than IgGs due to smaller size that improves target-to-background ratio (TBR) in in vivo imaging. Additionally, the ability to activate an optical probe after binding to the target greatly improves the TBR. An optical imaging probe based on a minibody against prostate-specific membrane antigen (PSMA-MB) and conjugated with an activatable fluorophore, indocyanine green (ICG), was designed to fluoresce only after binding to cell-surface PSMA. To further reduce background signal, short polyethylene glycol (PEG) linkers were employed to improve the covalent bonding ratio of ICG. New PSMA-MBs conjugated with bifunctional ICG derivatives specifically visualized PSMA-positive tumor xenografts in mice bearing both PSMA-positive and -negative tumors within 6 h postinjection. The addition of short PEG linkers significantly improved TBRs; however, it did not significantly alter the biodistribution. Thus, minibody-ICG conjugates could be a good alternative to IgG-ICG in the optical cancer imaging for further clinical applications.

  7. Fluorescence in vivo imaging of live tumor cells with pH-activatable targeted probes via receptor-mediated endocytosis

    NASA Astrophysics Data System (ADS)

    Asanuma, Daisuke; Urano, Yasuteru; Nagano, Tetsuo; Hama, Yukihiro; Koyama, Yoshinori; Kobayashi, Hisataka

    2009-02-01

    One goal of molecular imaging is to establish a widely applicable technique for specific detection of tumors with minimal background. Here, we achieve specific in vivo tumor visualization with a newly-designed "activatable" targeted fluorescence probe. This agent is activated after cellular internalization by sensing the pH change in the lysosome. Novel acidic pH-activatable probes based on the BODIPY fluorophore were synthesized, and then conjugated to a cancer-targeting monoclonal antibody, Trastuzumab, or galactosyl serum albumin (GSA). As proof of concept, ex and in vivo imaging of two different tumor mouse models was performed: HER2-overexpressed lung metastasis tumor with Trastuzumab-pH probe conjugates and lectin-overexpressed i.p. disseminated tumor with GSA-pH probe conjugates. These pH-activatable targeted probes were highly specific for tumors with minimal background signal. Because the acidic pH in lysosomes is maintained by the energy-consuming proton pump, only viable cancer cells were successfully visualized. Furthermore, this strategy was also applied to fluorescence endoscopy in tumor mouse models, resulting in specific visualization of tumors as small as submillimeter in size that could hardly detected by naked eyes because of their poor contrast against normal tissues. The design concept can be widely adapted to cancer-specific cell-surface-targeting molecules that result in cellular internalization.

  8. Photoacoustic Imaging: Semiconducting Oligomer Nanoparticles as an Activatable Photoacoustic Probe with Amplified Brightness for In Vivo Imaging of pH (Adv. Mater. 19/2016).

    PubMed

    Miao, Qingqing; Lyu, Yan; Ding, Dan; Pu, Kanyi

    2016-05-01

    Despite the great potential of photoacoustic imaging in the life sciences, the development of smart activatable photoacoustic probes remains elusive. On page 3662, K. Pu and co-workers report a facile nanoengineering approach based on semiconducting oligomer nano-particles to develop ratiometric photoacoustic probes with amplified brightness and enhanced sensing capability for accurate photoacoustic mapping of pH in the tumors of living mice.

  9. Activatable Optical Probes for the Detection of Enzymes

    PubMed Central

    Drake, Christopher R.; Miller, David C.; Jones, Ella F.

    2013-01-01

    The early detection of many human diseases is crucial if they are to be treated successfully. Therefore, the development of imaging techniques that can facilitate early detection of disease is of high importance. Changes in the levels of enzyme expression are known to occur in many diseases, making their accurate detection at low concentrations an area of considerable active research. Activatable fluorescent probes show immense promise in this area. If properly designed they should exhibit no signal until they interact with their target enzyme, reducing the level of background fluorescence and potentially endowing them with greater sensitivity. The mechanisms of fluorescence changes in activatable probes vary. This review aims to survey the field of activatable probes, focusing on their mechanisms of action as well as illustrating some of the in vitro and in vivo settings in which they have been employed. PMID:23519774

  10. Visualization of Protease Activity In Vivo Using an Activatable Photo-Acoustic Imaging Probe Based on CuS Nanoparticles

    PubMed Central

    Yang, Kai; Zhu, Lei; Nie, Liming; Sun, Xiaolian; Cheng, Liang; Wu, Chenxi; Niu, Gang; Chen, Xiaoyuan; Liu, Zhuang

    2014-01-01

    Herein, we for the first time report a novel activatable photoacoustic (PA) imaging nano-probe for in vivo detection of cancer-related matrix metalloproteinases (MMPs). A black hole quencher 3 (BHQ3) which absorbs red light is conjugated to near-infrared (NIR)-absorbing copper sulfide (CuS) nanoparticles via a MMP-cleavable peptide linker. The obtained CuS-peptide-BHQ3 (CPQ) nano-probe exhibits two distinctive absorption peaks at 630 nm and 930 nm. Inside the tumor microenviorment where MMPs present, the MMP-sensitive peptide would be cleaved, releasing BHQ3 from the CuS nanoparticles, the former of which as a small molecule is then rapidly cleared out from the tumor, whereas the latter of which as large nanoparticles would retain inside the tumor for a much longer period of time. As the result, the PA signal at 680 nm which is contributed by BHQ3 would be quickly diminished while that at 930 nm would be largely retained. The PA signal ratio of 680 nm / 930 nm could thus serve as an in vivo indicator of MMPs activity inside the tumor. Our work presents a novel strategy of in vivo sensing of MMPs based on PA imaging, which should offer remarkably improved detection depth compared with traditional optical imaging techniques. PMID:24465271

  11. Au@Ag/Au nanoparticles assembled with activatable aptamer probes as smart ``nano-doctors'' for image-guided cancer thermotherapy

    NASA Astrophysics Data System (ADS)

    Shi, Hui; Ye, Xiaosheng; He, Xiaoxiao; Wang, Kemin; Cui, Wensi; He, Dinggeng; Li, Duo; Jia, Xuekun

    2014-07-01

    Although nanomaterial-based theranostics have increased positive expectations from cancer treatment, it remains challenging to develop in vivo ``nano-doctors'' that provide high-contrast image-guided site-specific therapy. Here we designed an activatable theranostic nanoprobe (ATNP) via self-assembly of activatable aptamer probes (AAPs) on Au@Ag/Au nanoparticles (NPs). As both quenchers and heaters, novel Au@Ag/Au NPs were prepared, showing excellent fluorescence quenching and more effective near-infrared photothermal therapy than Au nanorods. The AAP comprised a thiolated aptamer and a fluorophore-labeled complementary DNA; thus, the ATNP with quenched fluorescence in the free state could realize signal activation through target binding-induced conformational change of the AAP, and then achieve on-demand treatment under image-guided irradiation. By using S6 aptamer as the model, in vitro and in vivo studies of A549 lung cancer verified that the ATNP greatly improved imaging contrast and specific destruction, suggesting a robust and versatile theranostic strategy for personalized medicine in future.Although nanomaterial-based theranostics have increased positive expectations from cancer treatment, it remains challenging to develop in vivo ``nano-doctors'' that provide high-contrast image-guided site-specific therapy. Here we designed an activatable theranostic nanoprobe (ATNP) via self-assembly of activatable aptamer probes (AAPs) on Au@Ag/Au nanoparticles (NPs). As both quenchers and heaters, novel Au@Ag/Au NPs were prepared, showing excellent fluorescence quenching and more effective near-infrared photothermal therapy than Au nanorods. The AAP comprised a thiolated aptamer and a fluorophore-labeled complementary DNA; thus, the ATNP with quenched fluorescence in the free state could realize signal activation through target binding-induced conformational change of the AAP, and then achieve on-demand treatment under image-guided irradiation. By using S6 aptamer as

  12. Microscale receiver operating characteristic analysis of micrometastasis recognition using activatable fluorescent probes indicates leukocyte imaging as a critical factor to enhance accuracy

    NASA Astrophysics Data System (ADS)

    Spring, Bryan Q.; Palanisami, Akilan; Hasan, Tayyaba

    2014-06-01

    Molecular-targeted probes are emerging with applications for optical biopsy of cancer. An underexplored potential clinical use of these probes is to monitor residual cancer micrometastases that escape cytoreductive surgery and chemotherapy. Here, we show that leukocytes, or white blood cells, residing in nontumor tissues-as well as those infiltrating micrometastatic lesions-uptake cancer cell-targeted, activatable immunoconjugates nonspecifically, which limits the accuracy and resolution of micrometastasis recognition using these probes. Receiver operating characteristic analysis of freshly excised tissues from a mouse model of peritoneal carcinomatosis suggests that dual-color imaging, adding an immunostain for leukocytes, offers promise for enabling accurate recognition of single cancer cells. Our results indicate that leukocyte identification improves micrometastasis recognition sensitivity and specificity from 92 to 93%-for multicellular metastases >20 to 30 μm in size-to 98 to 99.9% for resolving metastases as small as a single cell.

  13. Au@Ag/Au nanoparticles assembled with activatable aptamer probes as smart "nano-doctors" for image-guided cancer thermotherapy.

    PubMed

    Shi, Hui; Ye, Xiaosheng; He, Xiaoxiao; Wang, Kemin; Cui, Wensi; He, Dinggeng; Li, Duo; Jia, Xuekun

    2014-08-01

    Although nanomaterial-based theranostics have increased positive expectations from cancer treatment, it remains challenging to develop in vivo "nano-doctors" that provide high-contrast image-guided site-specific therapy. Here we designed an activatable theranostic nanoprobe (ATNP) via self-assembly of activatable aptamer probes (AAPs) on Au@Ag/Au nanoparticles (NPs). As both quenchers and heaters, novel Au@Ag/Au NPs were prepared, showing excellent fluorescence quenching and more effective near-infrared photothermal therapy than Au nanorods. The AAP comprised a thiolated aptamer and a fluorophore-labeled complementary DNA; thus, the ATNP with quenched fluorescence in the free state could realize signal activation through target binding-induced conformational change of the AAP, and then achieve on-demand treatment under image-guided irradiation. By using S6 aptamer as the model, in vitro and in vivo studies of A549 lung cancer verified that the ATNP greatly improved imaging contrast and specific destruction, suggesting a robust and versatile theranostic strategy for personalized medicine in future.

  14. Activatable Organic Near-Infrared Fluorescent Probes Based on a Bacteriochlorin Platform: Synthesis and Multicolor in Vivo Imaging with a Single Excitation

    PubMed Central

    2015-01-01

    Near infrared (NIR) fluorescent probes are ideal for in vivo imaging because they offer deeper tissue penetration and lower background autofluorescence. Although most fluorophores in this range are cyanine-based dyes, several new classes of fluorescent NIR probes have been developed. In this study, we developed organic bacteriochlorin derivatives, NMP4 and NMP5, which are excited with a single green light and emit different narrow, well-resolved bands in the NIR (peak of 739 and 770 nm for NMP4 and NMP5, respectively). When conjugated to galactosyl-human serum albumin (hGSA) or glucosyl-human serum albumin (glu-HSA), both targeting H-type lectins, including the β-d-galactose receptor expressing on ovarian cancer, these agents become targeted, activatable, single excitation, multicolor NIR fluorescence probes. After conjugation to either glu-HSA or hGSA, substantial quenching of fluorescence occurs that is reversed after cell binding and internalization. In vitro studies showed higher cancer cell uptake with NMP4 or NMP5 conjugated to hGSA compared to the same conjugates with glu-HSA. In vivo single excitation two-color imaging was performed after intraperitoneal injection of these agents into mice with disseminated ovarian cancer. Excited with a single green light, distinct NIR emission spectra from each fluorophore were detected and could be distinguished with spectral unmixing. In vivo results using a red fluorescence protein (RFP) labeled tumor model of disseminated ovarian cancer demonstrated high sensitivity and specificity for all probes. The success of single excitation, 2-color NIR fluorescence imaging with a new class of bacteriochlorin-based activatable fluorophores, NMP4 and NMP5, paves the way for further exploration of noncyanine dye-based NIR fluorophores. PMID:24450401

  15. In vivo imaging of intraperitoneally disseminated tumors in model mice by using activatable fluorescent small-molecular probes for activity of cathepsins.

    PubMed

    Fujii, Tomohiko; Kamiya, Mako; Urano, Yasuteru

    2014-10-15

    It is difficult to completely remove carcinomas in unguided ablative surgery because they cannot be distinguished with the unaided human eye. Therefore, in order to precisely visualize tiny tumors and the borders between cancerous lesions and normal tissues, we have been developing fluorescence probes activatable only in cancer cells. We previously reported the hydroxymethylrhodamine green (HMRG)-based fluorescence probe gGlu-HMRG for γ-glutamyltransferase (GGT), which is overexpressed in a variety of cancer cells, and we showed that it enables in vivo rapid detection of human ovarian cancer SHIN-3 nodules with a high tumor-to-background (T/B) fluorescence ratio in model mice. However, cancer cell lines with low GGT expression could hardly be detected with gGlu-HMRG. Here we developed two new HMRG-based fluorescence probes for the cathepsin family of cysteine proteases, including cathepsin B (CatB) and cathepsin L (CatL), which show increased expression and/or activity, secretion, and altered localization in many kinds of cancer cells. The developed probes, Z-Phe-Arg-HMRG and Z-Arg-Arg-HMRG, are colorless and nonfluorescent at the physiological pH of 7.4, but are hydrolyzed to HMRG upon reaction with purified cathepsins, resulting in a more than 200-fold fluorescence increase. These probes could visualize human ovarian cancer cell lines SHIN-3, SK-OV-3, and OVCAR-3, of which the latter two were hardly detectable with gGlu-HMRG. Z-Phe-Arg-HMRG showed higher applicability than Z-Arg-Arg-HMRG for in vivo imaging, and we confirmed that 0.5-mm-sized SK-OV-3 tumor nodules disseminated on the mesentery in a mouse model could be rapidly visualized by Z-Phe-Arg-HMRG, with a T/B fluorescence ratio of 4.2. Further, intraperitoneally disseminated tumor could be visualized in real time in vivo by fluorescence endoscopy after spraying Z-Phe-Arg-HMRG, with a T/B ratio of 3. In conclusion, our HMRG-based activatable probes targeted to cathepsins have expanded the detectable range

  16. Complementary optical and nuclear imaging of caspase-3 activity using combined activatable and radio-labeled multimodality molecular probe

    NASA Astrophysics Data System (ADS)

    Lee, Hyeran; Akers, Walter J.; Cheney, Philip P.; Edwards, W. Barry; Liang, Kexian; Culver, Joseph P.; Achilefu, Samuel

    2009-07-01

    Based on the capability of modulating fluorescence intensity by specific molecular events, we report a new multimodal optical-nuclear molecular probe with complementary reporting strategies. The molecular probe (LS498) consists of tetraazacyclododecanetetraacetic acid (DOTA) for chelating a radionuclide, a near-infrared fluorescent dye, and an efficient quencher dye. The two dyes are separated by a cleavable peptide substrate for caspase-3, a diagnostic enzyme that is upregulated in dying cells. LS498 is radiolabeled with 64Cu, a radionuclide used in positron emission tomography. In the native form, LS498 fluorescence is quenched until caspase-3 cleavage of the peptide substrate. Enzyme kinetics assay shows that LS498 is readily cleaved by caspase-3, with excellent enzyme kinetic parameters kcat and KM of 0.55+/-0.01 s-1 and 1.12+/-0.06 μM, respectively. In mice, the initial fluorescence of LS498 is ten-fold less than control. Using radiolabeled 64Cu-LS498 in a controlled and localized in-vivo model of caspase-3 activation, a time-dependent five-fold NIR fluorescence enhancement is observed, but radioactivity remains identical in caspase-3 positive and negative controls. These results demonstrate the feasibility of using radionuclide imaging for localizing and quantifying the distribution of molecular probes and optical imaging for reporting the functional status of diagnostic enzymes.

  17. Short PEG-linkers improve the performance of targeted, activatable monoclonal antibody-indocyanine green optical imaging probes.

    PubMed

    Sano, Kohei; Nakajima, Takahito; Miyazaki, Kiminori; Ohuchi, Yuya; Ikegami, Takashi; Choyke, Peter L; Kobayashi, Hisataka

    2013-05-15

    The ability to switch optical imaging probes from the quenched (off) to the active state (on) has greatly improved target to background ratios. The optimal activation efficiency of an optical probe depends on complete quenching before activation and complete dequenching after activation. For instance, monoclonal antibody-indocyanine green (mAb-ICG) conjugates, which are promising agents for clinical translation, are normally quenched, but can be activated when bound to a cell surface receptor and internalized. However, the small fraction of commonly used ICG derivative (ICG-Sulfo-OSu) can bind noncovalently to its mAb and is, thus, gradually released from the mAb leading to relatively high background signal especially in the liver and the abdomen. In this study, we re-engineered a mAb-ICG conjugate, (Panitumumab-ICG) using bifunctional ICG derivatives (ICG-PEG4-Sulfo-OSu and ICG-PEG8-Sulfo-OSu) with short polyethylene glycol (PEG) linkers. Higher covalent binding (70-86%) was observed using the bifunctional ICG with short PEG linkers resulting in less in vivo noncovalent dissociation. Panitumumab-ICG conjugates with short PEG linkers were able to detect human epidermal growth factor receptor 1 (EGFR)-positive tumors with high tumor-to-background ratios (15.8 and 6.9 for EGFR positive tumor-to-negative tumor and tumor-to-liver ratios, respectively, at 3 d postinjection).

  18. Activatable 19F MRI nanoparticle probes for the detection of reducing environments.

    PubMed

    Nakamura, Tatsuya; Matsushita, Hisashi; Sugihara, Fuminori; Yoshioka, Yoshichika; Mizukami, Shin; Kikuchi, Kazuya

    2015-01-12

    (19)F magnetic resonance imaging (MRI) probes that can detect biological phenomena such as cell dynamics, ion concentrations, and enzymatic activity have attracted significant attention. Although perfluorocarbon (PFC) encapsulated nanoparticles are of interest in molecular imaging owing to their high sensitivity, activatable PFC nanoparticles have not been developed. In this study, we showed for the first time that the paramagnetic relaxation enhancement (PRE) effect can efficiently decrease the (19)F NMR/MRI signals of PFCs in silica nanoparticles. On the basis of the PRE effect, we developed a reduction-responsive PFC-encapsulated nanoparticle probe, FLAME-SS-Gd(3+) (FSG). This is the first example of an activatable PFC-encapsulated nanoparticle that can be used for in vivo imaging. Calculations revealed that the ratio of fluorine atoms to Gd(3+) complexes per nanoparticle was more than approximately 5.0×10(2), resulting in the high signal augmentation. PMID:25413833

  19. Enzymatic activatable self-assembled peptide nanowire for targeted therapy and fluorescence imaging of tumors.

    PubMed

    Tang, Ying; Wu, Zhan; Zhang, Chong-Hua; Zhang, Xiao-Li; Jiang, Jian-Hui

    2016-03-01

    We developed novel activatable probe using self-assembled peptide nanowires with low affinity and toxicity to tumor cells in the absence of matrix metalloproteinase that showed activated high affinity and toxicity and provided a highly selective and efficient platform for targeted therapy and tumor imaging. PMID:26854263

  20. DNase-activatable fluorescence probes visualizing the degradation of exogenous DNA in living cells

    NASA Astrophysics Data System (ADS)

    Gong, Ping; Shi, Bihua; Zhang, Pengfei; Hu, Dehong; Zheng, Mingbin; Zheng, Cuifang; Gao, Duyang; Cai, Lintao

    2012-03-01

    This work presents a method to visualize the degradation of exogenous DNA in living cells using a novel type of activatable fluorescence imaging probe. Deoxyribonuclease (DNase)-activatable fluorescence probes (DFProbes) are composed of double strands deoxyribonucleic acid (dsDNA) which is labeled with fluorophore (ROX or Cy3) and quencher on the end of one of its strands, and stained with SYBR Green I. In the absence of DNase, DFProbes produce the green fluorescence signal of SYBR Green I. In the presence of DNase, SYBR Green I is removed from the DFProbes and the labeled fluorophore is separated from the quencher owing to the degradation of DFProbes by DNase, resulting in the decrease of the green fluorescence signal and the occurrence of a red fluorescence signal due to fluorescence resonance energy transfer (FRET). DNase in biological samples was detected using DFProbes and the fluorescence imaging in living cells was performed using DFprobe-modified Au nanoparticles. The results show that DFProbes have good responses to DNase, and can clearly visualize the degradation of exogenous DNA in cells in real time. The well-designed probes might be useful in tracing the dynamic changes of exogenous DNA and nanocarriers in vitro and in vivo.This work presents a method to visualize the degradation of exogenous DNA in living cells using a novel type of activatable fluorescence imaging probe. Deoxyribonuclease (DNase)-activatable fluorescence probes (DFProbes) are composed of double strands deoxyribonucleic acid (dsDNA) which is labeled with fluorophore (ROX or Cy3) and quencher on the end of one of its strands, and stained with SYBR Green I. In the absence of DNase, DFProbes produce the green fluorescence signal of SYBR Green I. In the presence of DNase, SYBR Green I is removed from the DFProbes and the labeled fluorophore is separated from the quencher owing to the degradation of DFProbes by DNase, resulting in the decrease of the green fluorescence signal and the

  1. The design and application of fluorophore–gold nanoparticle activatable probes

    PubMed Central

    Swierczewska, Magdalena; Lee, Seulki; Chen, Xiaoyuan

    2013-01-01

    Fluorescence-based assays and detection techniques are among the most highly sensitive and popular biological tests for researchers. To match the needs of research and the clinic, detection limits and specificities need to improve, however. One mechanism is to decrease non-specific background signals, which is most efficiently done by increasing fluorescence quenching abilities. Reports in the literature of theoretical and experimental work have shown that metallic gold surfaces and nanoparticles are ultra-efficient fluorescence quenchers. Based on these findings, subsequent reports have described gold nanoparticle fluorescence-based activatable probes that were designed to increase fluorescence intensity based on a range of stimuli. In this way, these probes can detect and signify assorted biomarkers and changes in environmental conditions. In this review, we explore the various factors and theoretical models that affect gold nanoparticle fluorescence quenching, explore current uses of activatable probes, and propose an engineering approach for future development of fluorescence based gold nanoparticle activatable probes. PMID:21380462

  2. Effect of reference spectra in spectral fitting to discriminate enzyme-activatable photoacoustic probe from intrinsic optical absorbers

    NASA Astrophysics Data System (ADS)

    Hirasawa, Takeshi; Okawa, Shinpei; Iwatate, Ryu J.; Kamiya, Mako; Urano, Yasuteru; Ishihara, Miya

    2016-03-01

    Multispectral photoacoustic (MS-PA) imaging has been researched to image molecular probes in the presence of strong background signals produced from intrinsic optical absorbers. Spectral fitting method (SFM) discriminates probe signals from background signals by fitting the PA spectra that are calculated from MS-PA images to reference spectra of the probe and background, respectively. Because hemoglobin is a dominant optical absorber in visible to near-infrared wavelength range, absorption spectra of hemoglobin have been widely used as reference background spectra. However, the spectra of background signals produced from heterogeneous biological tissue differ from the reference background spectra due to presence of other intrinsic optical absorbers and effect of optical scattering. Due to the difference, the background signals partly remain in the probe images. To image the probe injected in subcutaneous tumors of mice clearly, we added the melanosome absorption spectrum to the reference background spectra because skin contains nonnegligible concentration of melanosome and the spectrum is very similar to the scattering spectrum of biological tissue. The probe injected in the subcutaneous tumor of mice was an enzyme-activatable probe which show their original colors only in the presence of γ-glutamyltranspeptidase, an enzyme associated with cancer. The probes have been successfully used for rapid fluorescence imaging of cancer. As a result of MS-PA imaging, by considering the melanosome absorption spectrum, the background signals were successfully suppressed and then clearer probe image was obtained. Our MS-PA imaging method afforded successful imaging of tumors in mice injected with activatable PA probes.

  3. Activatable Water-Soluble Probes Enhance Tumor Imaging by Responding to Dysregulated pH and Exhibiting High Tumor-to-Liver Fluorescence Emission Contrast.

    PubMed

    Xiong, Hu; Kos, Petra; Yan, Yunfeng; Zhou, Kejin; Miller, Jason B; Elkassih, Sussana; Siegwart, Daniel J

    2016-07-20

    Dysregulated pH has been recognized as a universal tumor microenvironment signature that can delineate tumors from normal tissues. Existing fluorescent probes that activate in response to pH are hindered by either fast clearance (in the case of small molecules) or high liver background emission (in the case of large particles). There remains a need to design water-soluble, long circulating, pH-responsive nanoprobes with high tumor-to-liver contrast. Herein, we report a modular chemical strategy to create acidic pH-sensitive and water-soluble fluorescent probes for high in vivo tumor detection and minimal liver activation. A combination of a modified Knoevenagel reaction and PEGylation yielded a series of NIR BODIPY fluorophores with tunable pKas, high quantum yield, and optimal orbital energies to enable photoinduced electron transfer (PeT) activation in response to pH. After intravenous administration, Probe 5c localized to tumors and provided excellent tumor-to-liver contrast (apparent T/L = 3) because it minimally activates in the liver. This phenomenon was further confirmed by direct ex vivo imaging experiments on harvested organs. Because no targeting ligands were required, we believe that this report introduces a versatile strategy to directly synthesize soluble probes with broad potential utility including fluorescence-based image-guided surgery, cancer diagnosis, and theranostic nanomedicine.

  4. Activatable iRGD-based peptide monolith: Targeting, internalization, and fluorescence activation for precise tumor imaging.

    PubMed

    Cho, Hong-Jun; Lee, Sung-Jin; Park, Sung-Jun; Paik, Chang H; Lee, Sang-Myung; Kim, Sehoon; Lee, Yoon-Sik

    2016-09-10

    A disulfide-bridged cyclic RGD peptide, named iRGD (internalizing RGD, c(CRGDK/RGPD/EC)), is known to facilitate tumor targeting as well as tissue penetration. After the RGD motif-induced targeting on αv integrins expressed near tumor tissue, iRGD encounters proteolytic cleavage to expose the CendR motif that promotes penetration into cancer cells via the interaction with neuropilin-1. Based on these proteolytic cleavage and internalization mechanism, we designed an iRGD-based monolithic imaging probe that integrates multiple functions (cancer-specific targeting, internalization and fluorescence activation) within a small peptide framework. To provide the capability of activatable fluorescence signaling, we conjugated a fluorescent dye to the N-terminal of iRGD, which was linked to the internalizing sequence (CendR motif), and a quencher to the opposite C-terminal. It turned out that fluorescence activation of the dye/quencher-conjugated monolithic peptide probe requires dual (reductive and proteolytic) cleavages on both disulfide and amide bond of iRGD peptide. Furthermore, the cleavage of the iRGD peptide leading to fluorescence recovery was indeed operative depending on the tumor-related angiogenic receptors (αvβ3 integrin and neuropilin-1) in vitro as well as in vivo. Compared to an 'always fluorescent' iRGD control probe without quencher conjugation, the dye/quencher-conjugated activatable monolithic peptide probe visualized tumor regions more precisely with lower background noise after intravenous injection, owing to the multifunctional responses specific to tumor microenvironment. All these results, along with minimal in vitro and in vivo toxicity profiles, suggest potential of the iRGD-based activatable monolithic peptide probe as a promising imaging agent for precise tumor diagnosis. PMID:27349354

  5. Activatable iRGD-based peptide monolith: Targeting, internalization, and fluorescence activation for precise tumor imaging.

    PubMed

    Cho, Hong-Jun; Lee, Sung-Jin; Park, Sung-Jun; Paik, Chang H; Lee, Sang-Myung; Kim, Sehoon; Lee, Yoon-Sik

    2016-09-10

    A disulfide-bridged cyclic RGD peptide, named iRGD (internalizing RGD, c(CRGDK/RGPD/EC)), is known to facilitate tumor targeting as well as tissue penetration. After the RGD motif-induced targeting on αv integrins expressed near tumor tissue, iRGD encounters proteolytic cleavage to expose the CendR motif that promotes penetration into cancer cells via the interaction with neuropilin-1. Based on these proteolytic cleavage and internalization mechanism, we designed an iRGD-based monolithic imaging probe that integrates multiple functions (cancer-specific targeting, internalization and fluorescence activation) within a small peptide framework. To provide the capability of activatable fluorescence signaling, we conjugated a fluorescent dye to the N-terminal of iRGD, which was linked to the internalizing sequence (CendR motif), and a quencher to the opposite C-terminal. It turned out that fluorescence activation of the dye/quencher-conjugated monolithic peptide probe requires dual (reductive and proteolytic) cleavages on both disulfide and amide bond of iRGD peptide. Furthermore, the cleavage of the iRGD peptide leading to fluorescence recovery was indeed operative depending on the tumor-related angiogenic receptors (αvβ3 integrin and neuropilin-1) in vitro as well as in vivo. Compared to an 'always fluorescent' iRGD control probe without quencher conjugation, the dye/quencher-conjugated activatable monolithic peptide probe visualized tumor regions more precisely with lower background noise after intravenous injection, owing to the multifunctional responses specific to tumor microenvironment. All these results, along with minimal in vitro and in vivo toxicity profiles, suggest potential of the iRGD-based activatable monolithic peptide probe as a promising imaging agent for precise tumor diagnosis.

  6. Potential of activatable FAP-targeting immunoliposomes in intraoperative imaging of spontaneous metastases.

    PubMed

    Tansi, Felista L; Rüger, Ronny; Böhm, Claudia; Kontermann, Roland E; Teichgraeber, Ulf K; Fahr, Alfred; Hilger, Ingrid

    2016-05-01

    Despite intensive research and medical advances met, metastatic disease remains the most common cause of death in cancer patients. This results from late diagnosis, poor therapeutic response and undetected micrometastases and tumor margins during surgery. One approach to overcome these challenges involves fluorescence imaging, which exploits the properties of fluorescent probes for diagnostic detection of molecular structures at the onset of transformation and for intraoperative detection of metastases and tumor margins in real time. Considering these benefits, many contrast agents suitable for fluorescence imaging have been reported. However, most reports only demonstrate the detection of primary tumors and not the detection of metastases or their application in models of image-guided surgery. In this work, we demonstrate the influence of fibroblast activation protein (FAP) on the metastatic potential of fibrosarcoma cells and elucidate the efficacy of activatable FAP-targeting immunoliposomes (FAP-IL) for image-guided detection of the spontaneous metastases in mice models. Furthermore, we characterized the biodistribution and cellular localization of the liposomal fluorescent components in mice organs and traced their excretion over time in urine and feces. Taken together, activatable FAP-IL enhances intraoperative imaging of metastases. Their high accumulation in metastases, subsequent localization in the bile canaliculi and liver kupffer cells and suitable excretion in feces substantiates their potency as contrast agents for intraoperative imaging.

  7. Sensitive and selective tumor imaging with novel and highly activatable fluorescence strategies

    NASA Astrophysics Data System (ADS)

    Urano, Yasuteru

    2008-02-01

    Nowadays, several tumor imaging modalities such as MRI, PET and fluorescence imaging techniques have been extensively investigated. One of the central problems associated with these conventional tumor-targeted imaging methods, however, is the fact that the signal contrast between tumor and surrounding tissues relies on the efficient targeting to the tumor and the rapid sequestration or excretion of unbound agent. Among these modalities, only fluorescence imaging technique has a significant feature, in that great signal activation could be achieved which potentially leads to the selective imaging of cancer with higher tumor-to-background ratio. In this symposium, I will present some examples of fluorescence cancer imaging based on highly activatable strategies with using precisely designed novel fluorescence probes. Recently, we developed highly sensitive fluorescence probes for β-galactosidase which is applicable for living cell system. By utilizing these probes, we could establish a novel and highly activatable strategy for sensitive and selective optical imaging of imbedded tumor in the peritoneum. We took a two step procedure in that a lectin is used to localize β-galactosidase to cancer cells as an activating enzyme, and subsequent administration of a highly-sensitive fluorescence probe for the enzyme have afforded remarkable fluorescence activation selectively in tumor mass. Since the tumor-targeted enzyme can catalyze numerous substrate turnovers, a great number of fluorescent molecules could be produced and hence the rapid and sensitive detection of tumor in vivo with high tumor-to-background ratio could be achieved. Moreover, the consequent close-up investigation using fluorescence microscopy revealed that cancer microfoci as small as 200 μm could be successfully visualized.

  8. In vivo breast cancer characterization imaging using two monoclonal antibodies activatably labeled with near infrared fluorophores

    PubMed Central

    2012-01-01

    Introduction The gene expression profiles of cancer cells are closely related to their aggressiveness and metastatic potential. Antibody-based immunohistochemistry (IHC) of tissue specimens is a common method of identifying expressed proteins in cancer cells and increasingly inform treatment decisions. Molecular imaging is a potential method of performing similar IHC studies in vivo without the requirement for biopsy or tumor excision. To date, antibody-based imaging has been limited by high background levels related to slow clearance, making such imaging practical. However, optically activatable imaging agents, which are only fluorescent when bound to their cognate receptor, open the possibility of doing in vivo multi-color IHC. Methods We describe the use of activatable, near infrared fluorescence-labeled AlexaFluor680 (Alexa680) conjugated panitumumab (Pan) targeted against human epidermal growth factor receptor (EGFR) (Pan-Alexa680) and Indocyanine Green (ICG) conjugated trastuzumab (Tra) targeted against human epidermal growth factor receptor type 2 (HER2) (Tra-ICG) were synthesized and evaluated in cells in vitro and in an orthotopic breast cancer mouse model in vivo. Results Pan-Alexa680 (self-quenched; SQ) and Tra-ICG were initially quenched but demonstrated a 5.2- and 50-fold dequenching capacity under detergent treatment, respectively. In vitro microscopy and flow cytometry using MDA-MB-468 (EGFR+/HER2-) and 3T3/HER2 cells (EGFR-/HER2+), demonstrated specific fluorescence signal for each cell type based on binding to Pan-Alexa680(SQ) or Tra-ICG. An in vivo imaging study employing a cocktail of Pan-Alexa680(SQ) and Tra-ICG (each 50 μg) was injected into mice with orthotopic MDA-MB-468 and 3T3/HER2 tumors in the breast. Each probe visualized only the target-specific breast tumor. Conclusions Multi-color target-specific fluorescence breast cancer imaging can be achieved in vivo by employing two activatable fluorescent probes administered as a cocktail. The

  9. Gold Nanoparticle Based Activatable Probe for Sensing Ultra-Low Levels of Prostate Specific Antigen

    PubMed Central

    Liu, Dingbin; Huang, Xinglu; Wang, Zhantong; Jin, Albert; Sun, Xiaolian; Zhu, Lei; Wang, Fu; Ma, Ying; Niu, Gang; HightWalker, Angela R.; Chen, Xiaoyuan

    2013-01-01

    It is still in high demand to develop extremely sensitive and accurate clinical tools for biomarkers of interest for early diagnosis and monitoring of diseases. In this report, we present a highly sensitive and compatible gold nanoparticle (AuNP)-based fluorescence activatable probe for sensing ultra-low levels of prostate-specific antigen (PSA) in patient serum samples. The limit of detection of the newly-developed probe for PSA was pushed down to 0.032 pg/mL, which is more than two orders of magnitude lower than that of the conventional fluorescence probe. The ultrahigh sensitivity of this probe was attributed to the high loading efficiency of the dyes on AuNP surfaces and high fluorescence quenching unquenching abilities of the dye-AuNP pairs. The efficiency and robustness of this probe was investigated in patient serum samples, demonstrating the great potential of this probe in real-world applications. PMID:23683064

  10. Chiral, J-Aggregate-Forming Dyes for Alternative Signal Modulation Mechanisms in Self-Immolative Enzyme-Activatable Optical Probes.

    PubMed

    Sloniec-Myszk, Jagoda; Resch-Genger, Ute; Hennig, Andreas

    2016-02-11

    Enzyme-activatable optical probes are important for future advances in cancer imaging, but may easily suffer from low signal-to-background ratios unless not optimized. To address this shortcoming, numerous mechanisms to modulate the fluorescence signal have been explored. We report herein newly synthesized probes based on self-immolative linkers containing chiral J-aggregate-forming dyes. Signal modulation by formation of chiral J-aggregates is yet unexplored in optical enzyme probe design. The comprehensive characterization of the probes by absorption, CD, fluorescence, and time-resolved fluorescence spectroscopy revealed dye-dye interactions not observed for the free dyes in solution as well as dye-protein interactions with the enzyme. This suggested that J-aggregate formation is challenging to achieve with current probe design and that interactions of the dyes with the enzyme may interfere with achieving high signal-to-background ratios. The detailed understanding of the interactions provided herein provides valuable guidelines for the future design of similar probes.

  11. In vivo fluorescence imaging of atherosclerotic plaques with activatable cell-penetrating peptides targeting thrombin activity†

    PubMed Central

    Olson, Emilia S.; Whitney, Michael A.; Friedman, Beth; Aguilera, Todd A.; Crisp, Jessica L.; Baik, Fred M.; Jiang, Tao; Baird, Stephen M.; Tsimikas, Sotirios; Tsien, Roger Y.

    2012-01-01

    Thrombin and other coagulation enzymes have been shown to be important during atherosclerotic disease development. Study of these proteases is currently limited because of lack of robust molecular imaging agents for imaging protease activity in vivo. Activatable cell penetrating peptides (ACPPs) have been used to monitor MMP activity in tumors and, in principle, can be modified to detect other proteases. We have developed a probe that incorporates the peptide sequence DPRSFL from the proteinase activated receptor 1 (PAR-1) into an ACPP and shown that it is preferentially cleaved by purified thrombin. Active thrombin in serum cleaves DPRSFL–ACPP with >90% inhibition by lepirudin or argatroban. The DPRSFL–ACPP cleavage product accumulated in advanced atherosclerotic lesions in living mice, with 85% reduction in retention upon pre-injection of mice with hirudin. Uptake of the ACPP cleavage product was highest in plaques with histological features associated with more severe disease. Freshly resected human atheromas bathed in DPRSFL–ACPP retained 63% greater cleavage product compared to control ACPP. In conclusion, DPRSFL–ACPP can be used to study thrombin activity in coagulation and atherosclerosis with good spatial and temporal resolution. Thrombin-sensitive ACPPs may be developed into probes for early detection and intraoperative imaging of high risk atherosclerotic plaques. PMID:22534729

  12. Role of P38 MAPK on MMP Activity in Photothrombotic Stroke Mice as Measured using an Ultrafast MMP Activatable Probe

    PubMed Central

    Chang, Di; Wang, Yuan-Cheng; Bai, Ying-Ying; Lu, Chun-Qiang; Xu, Ting-Ting; Zhu, Lei; Ju, Shenghong

    2015-01-01

    Matrix metalloproteinases (MMPs) exert a dual effect in ischemic stroke and thus represent an ideal target for detection and therapy. However, to date, all clinical trials of MMP inhibitors have failed, and alternative drug candidates and therapeutic targets are urgently required. Nonetheless, further investigations are limited by the lack of non-invasive imaging techniques. Here, we report a novel, fast and ultrasensitive MMP activatable optical imaging probe for the dynamic visualization of MMP activity in photothrombotic stroke mice. This probe provides a significant signal enhancement in as little as 15 min, with the highest signal intensity occurring at 1 h post-injection, and shows high sensitivity in measuring MMP activity alterations, which makes it specifically suitable for the real-time visualization of MMP activity and drug discovery in preclinical research. Moreover, using this probe, we successfully demonstrate that the regulation of the p38 mitogen-activated protein kinase (MAPK) signal pathway is capable of modulating MMP activity after stroke, revealing a novel regulatory mechanism of postischemic brain damage and overcoming the limitations of traditional therapeutic strategies associated with MMP inhibitors by using a non-invasive molecular imaging method. PMID:26581247

  13. Design and synthesis of phospholipase C and A2-activatable near-infrared fluorescent smart probes.

    PubMed

    Popov, Anatoliy V; Mawn, Theresa M; Kim, Soungkyoo; Zheng, Gang; Delikatny, E James

    2010-10-20

    The primary focus of this work was to develop activatable probes suitable for in vivo detection of phospholipase activity. Phospholipases (PLs) are ubiquitous enzymes that perform a number of critical regulatory functions. They catalyze phospholipid breakdown and are categorized as A(1), A(2) (PLA(2)), C (PLC), and D (PLD) based on their site of action. Here, we report the design, synthesis, and characterization of self-quenching reporter probes that release fluorescent moieties upon cleavage with PLA(2) or PLC. A series of phospholipids were synthesized bearing the NIR fluorophore pyropheophorbide a (Pyro) at the sn-2 position. Fluorescence quenching was achieved by attachment of either a positively charged black hole quencher-3 (BHQ-3) to the phospholipid headgroup or another neutral Pyro moiety at the sn-1 position. The specificity to different phospholipases was modulated by insertion of spacers (C(6), C(12)) between Pyro and the lipid backbone. The specificity of the quenched fluorescent phospholipids was assayed on a plate reader against a number of phospholipases and compared with two commercial probes bearing the visible fluorophore BODIPY. While PyroC(6)-PyroC(6)-PtdCho revealed significant background fluorescence, and a 10% fluorescence increase under the action of PLA(2), Pyro-PtdEtn-BHQ demonstrated high selective sensitivity to PLC, particularly to the PC-PLC isoform, and its sensitivity to PLA(2) was negligible due to steric hindrance at the sn-2 position. In contrast, the C(12)-spacered PyroC(12)-PtdEtn-BHQ demonstrated a remarkable selectivity for PLA(2) and the best relative PLA(2)/PLC sensitivity, significantly outperforming previously known probes. These results open an avenue for future in vivo experiments and for new probes to detect PL activity. PMID:20882956

  14. Activatable molecular MRI nanoprobe for tumor cell imaging based on gadolinium oxide and iron oxide nanoparticle.

    PubMed

    Li, Jingjing; Wang, Shan; Wu, Chen; Dai, Yue; Hou, Pingfu; Han, Cuiping; Xu, Kai

    2016-12-15

    Activatable molecular MRI nanoprobe for intracellular GSH sensing was designed. As an alternative to "always on" nanoprobe, activatable imaging nanoprobes which are designed to amplify or boost imaging signals only in response to the targets have attracted more and more attention. In this paper, we designed a novel activatable molecular magnetic resonance imaging (MRI) nanoprobe for tumor cell recognization based on a MRI signal variation induced by the distance change between T1 and T2 contrast agents (CAs) in the presence of glutathione (GSH). To achieve this aim, carboxyl group functionalized iron oxide nanoparticles (Fe3O4 NPs) and polyethylene glycol-coated gadolinium oxide (PEG-Gd2O3) NPs as T2 and T1 MRI CA were connected by cystamine which contains a disulfide linkage. Transmission electron microscopic (TEM), X-ray photoelectron spectroscopy (XPS), energy dispersive spectrometer (EDS), fourier transform infrared spectroscopy (FT-IR), mass spectra and (1)H nuclear magnetic resonance spectroscopy ((1)H NMR) were introduced for their characterizations. The formation of Fe3O4-cystamine-Gd2O3 (Fe3O4-SS-Gd2O3) nanocomplex resulted in a quenched T1 signal due to the near proximity of PEG-Gd2O3 NPs to Fe3O4 NPs and a "light-up" T1 signal with the cleavage of disulfide bond in the presence of GSH. These results provide not only an easy way to realize MRI of tumor cells based on the overexpressed intracellular GSH level, but also a new insight for the design of activatable MRI nanoprobe. PMID:27501342

  15. Cucurbit[8]uril Regulated Activatable Supramolecular Photosensitizer for Targeted Cancer Imaging and Photodynamic Therapy.

    PubMed

    Wang, Xiao-Qiang; Lei, Qi; Zhu, Jing-Yi; Wang, Wen-Jing; Cheng, Qian; Gao, Fan; Sun, Yun-Xia; Zhang, Xian-Zheng

    2016-09-01

    Activatable photosensitizers (aPSs) have emerged as promising photodynamic therapy (PDT) agents for simultaneous imaging and selective ablation of cancer. However, traditional synthetic aPSs are limited by complex design and tedious synthesis. Here, aPS regulated by cucurbit[8]uril (CB[8]) for targeted cancer imaging and PDT is reported. This system is based on the host-guest interaction between biotinylated toluidine blue (TB-B) and CB[8] to form 2TB-B@CB[8]. Moreover, a facile strategy to turn off/on the fluorescence and photodynamic activity of TB-B is developed through the reversible assembly/disassembly of 2TB-B@CB[8]. This established system can achieve selective accumulation in tumor, light-up cancer imaging, and enhanced anticancer behavior. Therefore, this work provides a novel and promising strategy for the aPS build via simple and facile regulation of supramolecular chemistry. PMID:27513690

  16. Far-red light activatable, multifunctional prodrug for fluorescence optical imaging and combinational treatment.

    PubMed

    Bio, Moses; Rajaputra, Pallavi; Nkepang, Gregory; You, Youngjae

    2014-04-24

    We recently developed "photo-unclick chemistry", a novel chemical tool involving the cleavage of aminoacrylate by singlet oxygen, and demonstrated its application to visible light-activatable prodrugs. In this study, we prepared an advanced multifunctional prodrug, Pc-(L-CA4)2, composed of the fluorescent photosensitizer phthalocyanine (Pc), an SO-labile aminoacrylate linker (L), and a cytotoxic drug combretastatin A-4 (CA4). Pc-(L-CA4)2 had reduced dark toxicity compared with CA4. However, once illuminated, it showed improved toxicity similar to CA4 and displayed bystander effects in vitro. We monitored the time-dependent distribution of Pc-(L-CA4)2 using optical imaging with live mice. We also effectively ablated tumors by the illumination with far-red light to the mice, presumably through the combined effects of photodynamic therapy (PDT) and released chemotherapy drug, without any sign of acute systemic toxicity.

  17. Activatable fluorescent cys-diabody conjugated with indocyanine green derivative: consideration of fluorescent catabolite kinetics on molecular imaging.

    PubMed

    Sano, Kohei; Nakajima, Takahito; Ali, Towhid; Bartlett, Derek W; Wu, Anna M; Kim, Insook; Paik, Chang H; Choyke, Peter L; Kobayashi, Hisataka

    2013-10-01

    Antibody fragments including diabodies have more desirable pharmacokinetic characteristics than whole antibodies. An activatable optical imaging probe based on a cys-diabody targeting prostate-specific membrane antigen conjugated with the near-infrared fluorophore, indocyanine green (ICG), was designed such that it can only be activated when bound to the tumor, leading to high signal-to-background ratios. We employed short polyethylene glycol (PEG) linkers between the ICG and the reactive functional group (Sulfo-OSu group), resulting in covalent conjugation of ICG to the cys-diabody, which led to lower dissociation of ICG from cys-diabody early after injection, reducing hepatic uptake. However, unexpectedly, high and long-term fluorescence was observed in the kidneys, liver, and blood pool more than 1 h after injection of the cys-diabody PEG-ICG conjugate. A biodistribution study using I125-labeled cys-diabody-ICG showed immediate uptake in the kidneys followed by a rapid decrease, while gastric activity increased due to released radioiodine during rapid cys-diabody-ICG catabolism in the kidneys. To avoid this catabolic pathway, it would be preferable to use antibody fragments large enough not to be filtered through glomerulus or to conjugate the fragments with fluorescent dyes that are readily excreted into urine when cleaved from the cys-diabody to achieve high tumor-specific detection.

  18. Activatable fluorescent cys-diabody conjugated with indocyanine green derivative: consideration of fluorescent catabolite kinetics on molecular imaging

    PubMed Central

    Sano, Kohei; Nakajima, Takahito; Ali, Towhid; Bartlett, Derek W.; Wu, Anna M.; Kim, Insook; Paik, Chang H.; Choyke, Peter L.

    2013-01-01

    Abstract. Antibody fragments including diabodies have more desirable pharmacokinetic characteristics than whole antibodies. An activatable optical imaging probe based on a cys-diabody targeting prostate-specific membrane antigen conjugated with the near-infrared fluorophore, indocyanine green (ICG), was designed such that it can only be activated when bound to the tumor, leading to high signal-to-background ratios. We employed short polyethylene glycol (PEG) linkers between the ICG and the reactive functional group (Sulfo-OSu group), resulting in covalent conjugation of ICG to the cys-diabody, which led to lower dissociation of ICG from cys-diabody early after injection, reducing hepatic uptake. However, unexpectedly, high and long-term fluorescence was observed in the kidneys, liver, and blood pool more than 1 h after injection of the cys-diabody PEG-ICG conjugate. A biodistribution study using I125-labeled cys-diabody-ICG showed immediate uptake in the kidneys followed by a rapid decrease, while gastric activity increased due to released radioiodine during rapid cys-diabody-ICG catabolism in the kidneys. To avoid this catabolic pathway, it would be preferable to use antibody fragments large enough not to be filtered through glomerulus or to conjugate the fragments with fluorescent dyes that are readily excreted into urine when cleaved from the cys-diabody to achieve high tumor-specific detection. PMID:23752742

  19. Radioactive smart probe for potential corrected matrix metalloproteinase imaging.

    PubMed

    Huang, Chiun-Wei; Li, Zibo; Conti, Peter S

    2012-11-21

    Although various activatable optical probes have been developed to visualize metalloproteinase (MMP) activities in vivo, precise quantification of the enzyme activity is limited due to the inherent scattering and attenuation (limited depth penetration) properties of optical imaging. In this investigation, a novel activatable peptide probe (64)Cu-BBQ650-PLGVR-K(Cy5.5)-E-K(DOTA)-OH was constructed to detect tumor MMP activity in vivo. This agent is optically quenched in its native form, but releases strong fluorescence upon cleavage by selected enzymes. MMP specificity was confirmed both in vitro and in vivo by fluorescent imaging studies. The use of a single modality to image biomarkers/processes may lead to erroneous interpretation of imaging data. The introduction of a quantitative imaging modality, such as PET, would make it feasible to correct the enzyme activity determined from optical imaging. In this proof of principle report, we demonstrated the feasibility of correcting the activatable optical imaging data through the PET signal. This approach provides an attractive new strategy for accurate imaging of MMP activity, which may also be applied for other protease imaging. PMID:23025637

  20. Imaging Primary Mouse Sarcomas After Radiation Therapy Using Cathepsin-Activatable Fluorescent Imaging Agents

    SciTech Connect

    Cuneo, Kyle C.; Mito, Jeffrey K.; Javid, Melodi P.; Ferrer, Jorge M.; Kim, Yongbaek; Lee, W. David; Bawendi, Moungi G.; Brigman, Brian E.; Kirsch, David G.

    2013-05-01

    Purpose: Cathepsin-activated fluorescent probes can detect tumors in mice and in canine patients. We previously showed that these probes can detect microscopic residual sarcoma in the tumor bed of mice during gross total resection. Many patients with soft tissue sarcoma (STS) and other tumors undergo radiation therapy (RT) before surgery. This study assesses the effect of RT on the ability of cathepsin-activated probes to differentiate between normal and cancerous tissue. Methods and Materials: A genetically engineered mouse model of STS was used to generate primary hind limb sarcomas that were treated with hypofractionated RT. Mice were injected intravenously with cathepsin-activated fluorescent probes, and various tissues, including the tumor, were imaged using a hand-held imaging device. Resected tumor and normal muscle samples were harvested to assess cathepsin expression by Western blot. Uptake of activated probe was analyzed by flow cytometry and confocal microscopy. Parallel in vitro studies using mouse sarcoma cells were performed. Results: RT of primary STS in mice and mouse sarcoma cell lines caused no change in probe activation or cathepsin protease expression. Increasing radiation dose resulted in an upward trend in probe activation. Flow cytometry and immunofluorescence showed that a substantial proportion of probe-labeled cells were CD11b-positive tumor-associated immune cells. Conclusions: In this primary murine model of STS, RT did not affect the ability of cathepsin-activated probes to differentiate between tumor and normal muscle. Cathepsin-activated probes labeled tumor cells and tumor-associated macrophages. Our results suggest that it would be feasible to include patients who have received preoperative RT in clinical studies evaluating cathepsin-activated imaging probes.

  1. Acidic-pH-activatable fluorescence probes for visualizing exocytosis dynamics.

    PubMed

    Asanuma, Daisuke; Takaoka, Yousuke; Namiki, Shigeyuki; Takikawa, Kenji; Kamiya, Mako; Nagano, Tetsuo; Urano, Yasuteru; Hirose, Kenzo

    2014-06-10

    Live imaging of exocytosis dynamics is crucial for a precise spatiotemporal understanding of secretion phenomena, but current approaches have serious limitations. We designed and synthesized small-molecular fluorescent probes that were chemically optimized for sensing acidic intravesicular pH values, and established that they can be used to sensitively and reliably visualize vesicular dynamics following stimulation. This straightforward technique for the visualization of exocytosis as well as endocytosis/reacidification processes with high spatiotemporal precision is expected to be a powerful tool for investigating dynamic cellular phenomena involving changes in the pH value.

  2. pH-Activatable MnO-Based Fluorescence and Magnetic Resonance Bimodal Nanoprobe for Cancer Imaging.

    PubMed

    Hsu, Benedict You Wei; Ng, Michael; Tan, Aaron; Connell, John; Roberts, Thomas; Lythgoe, Mark; Zhang, Yu; Wong, Siew Yee; Bhakoo, Kishore; Seifalian, Alexander M; Li, Xu; Wang, John

    2016-03-01

    Stimuli-responsive nanoprobes that combine both fluorescence and magnetic resonance imaging (MRI) are anticipated to be highly beneficial for tumor visualization with high imaging sensitivity. By employing an interfacial templating scheme, a pH-activatable fluorescence/MRI dual-modality imaging nanoprobe is successfully developed based on the coencapsulation of MnO nanoparticles and coumarin-545T inside a hybrid silica nanoshell. To promote cancer cell targeting with high-specificity, the nanoprobes are also conjugated with folic acid to establish a greater affinity for cancer cells that over-express folate receptors on their cell membrane. In the new nanosystem, MnO nanoparticles are shown to function as an efficient fluorescence quencher of coumarin-545T prior to cellular uptake. However, fluorescence recovery is achieved upon acidic dissolution of the MnO nanoparticles following receptor-mediated endocytosis into the low pH compartments of the cancer cells. Meanwhile, the Mn(2+) ions thus released are also shown to exert a strong T1 contrast enhancement in the cancer cells. Therefore, by demonstrating the dual-activatable MRI and fluorescence imaging in response to the low pH conditions, it is envisioned that these nanoprobes would have tremendous potential for emerging cancer-imaging modalities such as image-guided cancer therapy. PMID:26895111

  3. An albumin nanocomplex-based endosomal pH-activatable on/off probe system.

    PubMed

    Lee, Changkyu; Lee, Seunghyun; Thao, Le Quang; Hwang, Ha Shin; Kim, Jong Oh; Lee, Eun Seong; Oh, Kyung Taek; Shin, Beom Soo; Choi, Han-Gon; Youn, Yu Seok

    2016-08-01

    Albumin has gained considerable interest as a material for fabricating nanoparticulate systems due to its biomedical advantages, such as biocompatibility and chemical functionality. Here, we report a new pH-sensitive albumin nanocomplex prototype with a zinc-imidazole coordination bond. Albumin was conjugated with 1-(3-aminopropyl)imidazole and mPEG10kDa-NHS, and the resulting albumin conjugate (PBI) was then modified with either Cy5.5 or BHQ-3. The newly formed albumin nanocomplex (C/BQ-PBI Zn NCs: ∼116nm) system was facilely self-assembled around pH 7.4 in the presence of Zn(2+), but it quickly disassembled in an acidic environment (∼pH 5.0). Based on this pH-sensitivity, C/BQ-PBI Zn NCs emitted strong near-infrared fluorescence and released Zn(2+), turning "off" at pH ∼7.4 (e.g., plasma) and "on" at pH ∼5.0 (e.g., endo/lysosomes in tumor cells) on account of fluorescence resonance energy transfer. C/BQ-PBI Zn NCs displayed significant cytotoxicity due to an increase in cellular Zn(2+) in response to endosomal pH (∼5.0) in breast cancer MCF-7 cells and lung adenocarcinoma A549 cells. Particularly, confocal laser scanning microscopic images showed a strong fluorescence signal caused by the disassembly of C/BQ-PBI Zn NCs in the endosomal region of MCF-7 cells. Based on these results, we believe that this albumin nanocomplex is an attractive biocompatible tumor targeting probe carrier for the theranostic purpose.

  4. Polypeptide micelles with dual pH activatable dyes for sensing cells and cancer imaging

    NASA Astrophysics Data System (ADS)

    Gong, Ping; Yang, Yueting; Yi, Huqiang; Fang, Shengtao; Zhang, Pengfei; Sheng, Zonghai; Gao, Guanhui; Gao, Duyang; Cai, Lintao

    2014-04-01

    pH is an important control parameter for maintenance of cell viability and tissue functions. pH monitoring provides valuable information on cell metabolic processes and the living environment. In this study, we prepared dual pH-sensitive, fluorescent dye-loaded polypeptide nanoparticles (DPNs) for ratiometric sensing of pH changes in living cells. DPNs contain two types of dyes: N-(rhodamine B) lactam cystamine (RBLC), an acid activatable fluorescent dye with increased fluorescence in an acidic environment, and fluorescein isothiocyanate (FITC), a base activatable fluorescent dye with enhanced fluorescence in an alkaline environment. Hence, DPNs exhibited a dual response signal with strong red fluorescence and weak green fluorescence under acidic conditions; in contrast, they showed strong green fluorescence and almost no red fluorescence under alkaline and neutral conditions. The favorable inverse pH responses of the two fluorescent dyes resulted in ratiometric pH determination for DPNs with an optimized pH-sensitive range of pH 4.5-7.5. Quantitative analysis of the intracellular pH of intact MCF-7 cells has been successfully demonstrated with our nanosensor. Moreover, single acid activatable fluorescent dye doped polypeptide nanoparticles that only contained RBLC can distinguish tumor tissue from normal tissue by monitoring the acidic extracellular environment.pH is an important control parameter for maintenance of cell viability and tissue functions. pH monitoring provides valuable information on cell metabolic processes and the living environment. In this study, we prepared dual pH-sensitive, fluorescent dye-loaded polypeptide nanoparticles (DPNs) for ratiometric sensing of pH changes in living cells. DPNs contain two types of dyes: N-(rhodamine B) lactam cystamine (RBLC), an acid activatable fluorescent dye with increased fluorescence in an acidic environment, and fluorescein isothiocyanate (FITC), a base activatable fluorescent dye with enhanced fluorescence

  5. Site-specific conjugation of the quencher on peptide's N-terminal for the synthesis of a targeted non-spreading activatable optical probe.

    PubMed

    Simard, Bryan; Mironov, Gleb G; Tomanek, Boguslaw; van Veggel, Frank C J M; Abulrob, Abedelnasser

    2016-06-01

    Optical imaging offers high sensitivity and portability at low cost. The design of 'smart' or 'activatable' probes can decrease the background noise and increase the specificity of the signal. By conjugating a fluorescent dye and a compatible quencher on each side of an enzyme's substrate, the signal remains in its 'off ' state until it reaches the area where a specific enzyme is expressed. However, the signal can leak from that area unless the dye is attached to a molecule able to bind to a specific target also presented in that area. The aim of this study was to (i) specifically conjugate the quencher on the α-amino group of the peptide's N-terminus, (ii) conjugate the dye on the ε-amino group of a lysine in C-terminus, and (iii) conjugate the carboxyl group of the peptide's C-terminus to an amino group present on an antibody, using carbodiimide chemistry. The use of protecting groups, such as Boc or Fmoc, to allow site-specific conjugation, presents several drawbacks including 'on beads labeling', additional steps required for deprotection and removal from the resin, decreased yield, and dye degradation. A method of preferential labeling of α-amino N-terminal group in slightly acidic solution, proposed by Selo et al. (1996) has partially solved the problem. The present study reports improvements of the method allowing to (i) avoid the homo-bilabeling, (ii) increase the yield of the N-terminal labeling by two folds, and (iii) decrease the cost by 44-fold. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. PMID:27282138

  6. An activatable multimodal/multifunctional nanoprobe for direct imaging of intracellular drug delivery

    PubMed Central

    Mitra, Rajendra N.; Doshi, Mona; Zhang, Xiaolei; Tyus, Jessica C.; Bengtsson, Niclas; Fletcher, Steven; Page, Brent D. G.; Turkson, James; Gesquiere, Andre J.; Gunning, Patrick T.; Walter, Glenn A.; Santra, Swadeshmukul

    2011-01-01

    Multifunctional nanoparticles integrated with imaging modalities (such as magnetic resonance and optical) and therapeutic drugs are promising candidates for future cancer diagnostics and therapy. While targeted drug delivery and imaging of tumor cells have been the major focus in engineering nanoparticle probes, no extensive efforts have been made towards developing sensing probes that can confirm and monitor intra-cellular drug release events. Here, we present quantum dot (Qdot)-iron oxide (IO) based multimodal/multifunctional nanocomposite probe that is optically and magnetically imageable, targetable and capable of reporting on intra-cellular drug release events. Specifically, the probe consists of a superparamagnetic iron oxide nanoparticle core (IONP) decorated with satellite CdS:Mn/ZnS Qdots where the Qdots themselves are further functionalized with STAT3 inhibitor (an anti-cancer agent), vitamin folate (as targeting motif) and m-polyethylene glycol (m-PEG, a hydrophilic dispersing agent). The Qdot luminescence is quenched in this nanocomposite probe (“OFF” state) due to combined electron/energy transfer mediated quenching processes involving IONP, folate and STAT3 agents. Upon intracellular uptake, the probe is exposed to the cytosolic glutathione (GSH) containing environment resulting in restoration of the Qdot luminescence (“ON” state), which reports on uptake and drug release. Probe functionality was validated using fluorescence and MR measurements as well as in vitro studies using cancer cells that overexpress folate receptors. PMID:22078810

  7. Polypeptide micelles with dual pH activatable dyes for sensing cells and cancer imaging.

    PubMed

    Gong, Ping; Yang, Yueting; Yi, Huqiang; Fang, Shengtao; Zhang, Pengfei; Sheng, Zonghai; Gao, Guanhui; Gao, Duyang; Cai, Lintao

    2014-05-21

    pH is an important control parameter for maintenance of cell viability and tissue functions. pH monitoring provides valuable information on cell metabolic processes and the living environment. In this study, we prepared dual pH-sensitive, fluorescent dye-loaded polypeptide nanoparticles (DPNs) for ratiometric sensing of pH changes in living cells. DPNs contain two types of dyes: N-(rhodamine B) lactam cystamine (RBLC), an acid activatable fluorescent dye with increased fluorescence in an acidic environment, and fluorescein isothiocyanate (FITC), a base activatable fluorescent dye with enhanced fluorescence in an alkaline environment. Hence, DPNs exhibited a dual response signal with strong red fluorescence and weak green fluorescence under acidic conditions; in contrast, they showed strong green fluorescence and almost no red fluorescence under alkaline and neutral conditions. The favorable inverse pH responses of the two fluorescent dyes resulted in ratiometric pH determination for DPNs with an optimized pH-sensitive range of pH 4.5-7.5. Quantitative analysis of the intracellular pH of intact MCF-7 cells has been successfully demonstrated with our nanosensor. Moreover, single acid activatable fluorescent dye doped polypeptide nanoparticles that only contained RBLC can distinguish tumor tissue from normal tissue by monitoring the acidic extracellular environment.

  8. Polypyrrole-based nanotheranostics for activatable fluorescence imaging and chemo/photothermal dual therapy of triple-negative breast cancer

    NASA Astrophysics Data System (ADS)

    Park, Dongjin; Ahn, Kyung-Ohk; Jeong, Kyung-Chae; Choi, Yongdoo

    2016-05-01

    Here, we fabricated polypyrrole nanoparticles (PPys) (termed HA10-PPy, HA20-PPy, and HA40-PPy) doped with different average molecular weight hyaluronic acids (HAs) (10, 20, and 40 kDa, respectively), and evaluated the effect of molecular weight of doped HA on photothermal induction, fluorescence quenching, and drug loading efficiencies. Doxorubicin-loaded HA-doped PPys (DOX@HA-PPys) could be used for imaging and therapy of triple-negative breast cancer (TNBC). Fluorescence turn-on, stimuli-responsive drug release, and photo-induced heating of DOX@HA-PPys enabled not only activatable fluorescence imaging but also subsequent chemo/photothermal dual therapy for TNBC. In particular, we illustrated the potential usefulness of the photothermal effect of the nanoparticles for overcoming chemoresistance in TNBC.

  9. Magnetic resonance imaging of stem cell apoptosis in arthritic joints with a caspase activatable contrast agent.

    PubMed

    Nejadnik, Hossein; Ye, Deju; Lenkov, Olga D; Donig, Jessica S; Martin, John E; Castillo, Rostislav; Derugin, Nikita; Sennino, Barbara; Rao, Jianghong; Daldrup-Link, Heike

    2015-02-24

    About 43 million individuals in the U.S. encounter cartilage injuries due to trauma or osteoarthritis, leading to joint pain and functional disability. Matrix-associated stem cell implants (MASI) represent a promising approach for repair of cartilage defects. However, limited survival of MASI creates a significant bottleneck for successful cartilage regeneration outcomes and functional reconstitution. We report an approach for noninvasive detection of stem cell apoptosis with magnetic resonance imaging (MRI), based on a caspase-3-sensitive nanoaggregation MRI probe (C-SNAM). C-SNAM self-assembles into nanoparticles after hydrolysis by caspase-3, leading to 90% amplification of (1)H MR signal and prolonged in vivo retention. Following intra-articular injection, C-SNAM causes significant MR signal enhancement in apoptotic MASI compared to viable MASI. Our results indicate that C-SNAM functions as an imaging probe for stem cell apoptosis in MASI. This concept could be applied to a broad range of cell transplants and target sites.

  10. Hybrid graphene/Au activatable theranostic agent for multimodalities imaging guided enhanced photothermal therapy.

    PubMed

    Gao, Shi; Zhang, Liwen; Wang, Guohao; Yang, Kai; Chen, Minglong; Tian, Rui; Ma, Qingjie; Zhu, Lei

    2016-02-01

    Photothermal therapy (PTT) has been increasingly investigated. However, there are still challenges in strategies that can further enhance photoconversion efficiency and improve photothermal tumor ablation effect of current nanomaterials. Herein, we developed a fluorescent/photoacoustic imaging guided PTT agent by seeding Gold (Au) nanoparticles onto graphene oxide (GO). Near infrared dye (Cy5.5) labeled-matrix metalloproteinase-14 (MMP-14) substrate (CP) was conjugated onto the GO/Au complex (GA) forming tumor targeted theranostic probe (CPGA), whereCy5.5 fluorescent signal is quenched by Surface Plasmon Resonance (SPR) capacity from both GO and Au, yet it can boost strong fluorescence signals after degradation by MMP-14. The photothermal effect of GA hybrid was found significantly elevated compared with Au or GO alone. After intravenous administration of CPGA into SCC7 tumor-bearing mice, high fluorescence and PA signals were observed in the tumor area over time, which peaked at the 6 h time point (tumor-to-normal tissue ratio of 3.64 ± 0.51 for optical imaging and 2.5 ± 0.27 for PA imaging). The tumors were then irradiated with a laser, and an excellent tumor inhibition was observedwithoutrecurrence. Our studies further encourage applications of the hybrid nanocomposite for image-guided enhanced PTT in biomedical applications, especially in cancer theranostics. PMID:26691399

  11. Activatable hyaluronic acid nanoparticle as a theranostic agent for optical/photoacoustic image-guided photothermal therapy.

    PubMed

    Zhang, Liwen; Gao, Shi; Zhang, Fan; Yang, Kai; Ma, Qingjie; Zhu, Lei

    2014-12-23

    Photothermal therapy (PTT) is an emerging treatment modality that is under intensive preclinical investigations for the treatment of various medical conditions, including cancer. However, the lack of targeting function of PTT agents hampers its clinical application. An effective and nontoxic delivery vehicle that can carry PTT agents into tumor areas is still needed urgently. In this study, we developed a multifunctional nanocomposite by loading copper sulfide (CuS) into Cy5.5-conjugated hyaluronic acid nanoparticles (HANP), obtaining an activatable Cy5.5-HANP/CuS (HANPC) nanocomposite. In this system, Cy5.5 fluorescent signal is quenched by CuS inside the particle until the whole nanocomposite is degraded by hyaluronidase present in tumor, giving strong fluorescence signals delineating the tumor. Importantly, CuS with strong NIR absorbance appears to be an excellent contrast agent for photoacoustic (PA) imaging and an effective PTT agent. After intravenous administration of HANPC into SCC7 tumor-bearing mice, high fluorescence and PA signals were observed in the tumor area over time, which peaked at the 6 h time point (tumor-to-normal tissue ratio of 3.25±0.25 for optical imaging and 3.8±0.42 for PA imaging). The tumors were then irradiated with a laser, and a good tumor inhibition rate (89.74% on day 5) was observed. Our studies further encourage application of this HA-based multifunctional nanocomposite for image-guided PTT in biomedical applications, especially in cancer theranostics. PMID:25402600

  12. Multispectral imaging probe

    DOEpatents

    Sandison, David R.; Platzbecker, Mark R.; Descour, Michael R.; Armour, David L.; Craig, Marcus J.; Richards-Kortum, Rebecca

    1999-01-01

    A multispectral imaging probe delivers a range of wavelengths of excitation light to a target and collects a range of expressed light wavelengths. The multispectral imaging probe is adapted for mobile use and use in confined spaces, and is sealed against the effects of hostile environments. The multispectral imaging probe comprises a housing that defines a sealed volume that is substantially sealed from the surrounding environment. A beam splitting device mounts within the sealed volume. Excitation light is directed to the beam splitting device, which directs the excitation light to a target. Expressed light from the target reaches the beam splitting device along a path coaxial with the path traveled by the excitation light from the beam splitting device to the target. The beam splitting device directs expressed light to a collection subsystem for delivery to a detector.

  13. Multispectral imaging probe

    DOEpatents

    Sandison, D.R.; Platzbecker, M.R.; Descour, M.R.; Armour, D.L.; Craig, M.J.; Richards-Kortum, R.

    1999-07-27

    A multispectral imaging probe delivers a range of wavelengths of excitation light to a target and collects a range of expressed light wavelengths. The multispectral imaging probe is adapted for mobile use and use in confined spaces, and is sealed against the effects of hostile environments. The multispectral imaging probe comprises a housing that defines a sealed volume that is substantially sealed from the surrounding environment. A beam splitting device mounts within the sealed volume. Excitation light is directed to the beam splitting device, which directs the excitation light to a target. Expressed light from the target reaches the beam splitting device along a path coaxial with the path traveled by the excitation light from the beam splitting device to the target. The beam splitting device directs expressed light to a collection subsystem for delivery to a detector. 8 figs.

  14. Theranostic nanoparticles for enzyme-activatable fluorescence imaging and photodynamic/chemo dual therapy of triple-negative breast cancer

    PubMed Central

    Choi, Jaehee; Kim, Hyunjin

    2015-01-01

    Background Triple-negative breast cancer (TNBC) is a highly diverse group of cancers characterized by tumors that does not express estrogen and progesterone receptors, as well as human epidermal growth factor receptor 2 (HER2) gene expression. TNBC is associated with poor prognosis due to high rate of recurrence and distance metastasis, lack of response to hormonal or HER2-targeted therapies, and partial response to chemotherapy. Hence, development of new therapeutic strategies to overcome such limitations is of great importance. Here we describe the application of photosensitizer-conjugated and camptothecin (CPT)-encapsulated hyaluronic acid (HA) nanoparticles as enzyme-activatable theranostic nanoparticles (EATNP) for near-infrared (NIR) fluorescence imaging and photodynamic/chemo dual therapy of TNBC. Methods For the preparation of EATNPs, chlorin e6 (Ce6), a second generation photosensitizer, was covalently conjugated to a monomethoxy poly(ethylene glycol)-grafted HA backbone. Ce6-conjugated HA (Ce6-HA) formed self-assembled nanoparticles (i.e., Ce6-HA NPs) in an aqueous solution. Subsequently, CPT, a topoisomerase 1 inhibitor with remarkable anticancer efficacy but with low water solubility, was encapsulated inside the hydrophobic core of Ce6-HA NPs thereby forming EATNPs. Results Fluorescence and singlet oxygen generation (SOG) of EATNPs are quenched in its native state. Treatment of EATNPs with hyaluronidase (HAdase) induces enzyme concentration-dependent activation of NIR fluorescence and SOG. Moreover, HAdase-mediated degradation of the nanoparticles also triggers the release of CPT from the EATNPs. In vitro confocal microscopy and cytotoxicity tests confirmed that EATNPs were efficiently introduced into MDA-MB-231 TNBC cell line, thereby inducing better cytotoxicity than that by free CPT. Additional light irradiation onto the EATNP-treated cells significantly increased therapeutic efficacy in TNBC, which indicates that EATNP plays an important role in

  15. Acid-Activatable Michael-Type Fluorescent Probes for Thiols and for Labeling Lysosomes in Live Cells.

    PubMed

    Dai, Chun-Guang; Du, Xiao-Jiao; Song, Qin-Hua

    2015-12-18

    A Michael addition is usually taken as a base-catalyzed reaction. Most fluorescent probes have been designed to detect thiols in slightly alkaline solutions (pH 7-9). The sensing reactions of almost all Michael-type fluorescent probes for thiols are faster in a high pH solution than in a low pH solution. In this work, we synthesized a series of 7-substituted 2-(quinolin-2-ylmethylene)malonic acids (QMAs, substituents: NEt2, OH, H, Cl, or NO2) and their ethyl esters (QMEs) as Michael-type fluorescent probes for thiols. The sensing reactions of QMAs and QMEs occur in distinct pH ranges, pH < 7 for QMAs and pH > 7 for QMEs. On the basis of experimental and theoretic studies, we have clarified the distinct pH effects on the sensing reactivity between QMAs and QMEs and demonstrated that two QMAs (NEt2, OH) are highly sensitive and selective fluorescent probes for thiols in acidic solutions (pH < 7) and promising dyes that can label lysosomes in live cells.

  16. Highly activatable and environment-insensitive optical highlighters for selective spatiotemporal imaging of target proteins.

    PubMed

    Kobayashi, Tomonori; Komatsu, Toru; Kamiya, Mako; Campos, Cláudia; González-Gaitán, Marcos; Terai, Takuya; Hanaoka, Kenjiro; Nagano, Tetsuo; Urano, Yasuteru

    2012-07-11

    Optical highlighters are photoactivatable fluorescent molecules that exhibit pronounced changes in their spectral properties in response to irradiation with light of a specific wavelength and intensity. Here, we present a novel design strategy for a new class of caged BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) fluorophores, based on the use of photoremovable protecting groups (PRPGs) with high reduction potentials that serve as both a photosensitive unit and a fluorescence quencher via photoinduced electron transfer (PeT). 2,6-Dinitrobenzyl (DNB)-caged BODIPY was efficiently photoactivated, with activation ratios exceeding 600-fold in aqueous solutions. We then combined this photoactivatable fluorophore with a SNAP (mutant of O(6)-alkylguanine DNA alkyltransferase) ligand to obtain a small-molecule-based optical highlighter for visualization of protein dynamics, using the well-established SNAP tag technology. As proof of concept, we demonstrate spatiotemporal imaging of the fusion protein of epidermal growth factor receptor (EGFR) with SNAP tag in living cells. We also demonstrate highlighting of cells of interest in live zebrafish embryos, using the fusion protein of histone 2A with SNAP tag.

  17. ROS-Responsive Activatable Photosensitizing Agent for Imaging and Photodynamic Therapy of Activated Macrophages

    PubMed Central

    Kim, Hyunjin; Kim, Youngmi; Kim, In-Hoo; Kim, Kyungtae; Choi, Yongdoo

    2014-01-01

    The optical properties of macrophage-targeted theranostic nanoparticles (MacTNP) prepared from a Chlorin e6 (Ce6)-hyaluronic acid (HA) conjugate can be activated by reactive oxygen species (ROS) in macrophage cells. MacTNP are nonfluorescent and nonphototoxic in their native state. However, when treated with ROS, especially peroxynitrite, they become highly fluorescent and phototoxic. In vitro cell studies show that MacTNP emit near-infrared (NIR) fluorescence inside activated macrophages. The NIR fluorescence is quenched in the extracellular environment. MacTNP are nontoxic in macrophages up to a Ce6 concentration of 10 μM in the absence of light. However, MacTNP become phototoxic upon illumination in a light dose-dependent manner. In particular, significantly higher phototoxic effect is observed in the activated macrophage cells compared to human dermal fibroblasts and non-activated macrophages. The ROS-responsive MacTNP, with their high target-to-background ratio, may have a significant potential in selective NIR fluorescence imaging and in subsequent photodynamic therapy of atherosclerosis with minimum side effects. PMID:24396511

  18. Indocyanine green encapsulated nanogels for hyaluronidase activatable and selective near infrared imaging of tumors and lymph nodes.

    PubMed

    Mok, Hyejung; Jeong, Hyunkyung; Kim, Sun-Jung; Chung, Bong Hyun

    2012-09-01

    Indocyanine green (ICG) encapsulated hyaluronic acid (HA) nanogels were first studied for highly selective detection of specific cancers and lymph nodes via hyaluronidase sensitive switch-on of near infrared fluorescence as a long-lasting and stimuli-responsive imaging probe.

  19. Probing intra-cellular drug release event using activatable (OFF/ON) CdS:Mn/ZnS quantum dots (Qdots): spectroscopic studies to investigate interaction of Qdots with quencher

    NASA Astrophysics Data System (ADS)

    Tharkur, Jeremy; Teblum, Andrew; Basumallick, Srijita; Shah, Rikhav; Cantarero, Karishma; Maity, Niharika; Rifai, Sara; Doshi, Mona; Gesquiere, Andre J.; Santra, Swadeshmukul

    2013-02-01

    In recent years, activatable Quantum Dots (AQdots) are gaining popularity in a number of chemical and biological sensing applications. A basic design of AQdot probes involves a suitable quencher which is capable of altering optical properties of the Qdots. In our previous studies we have shown that CdS:Mn/ZnS fluorescence can be effectively quenched using small molecule quenchers (such as dopamine, chemotherapeutic drug) as well as iron oxide nanoparticle via electron/energy transfer process. We have also shown that the quenched Qdot fluorescence can be restored when the Qdots are separated from the quencher. Using Qdot based activatable probes, we detected intracellular drug release event. Qdot fluorescence was restored upon interaction with the intracellular glutathione (GSH). In this paper, we report a GSH induced quenching of water-soluble N-Acetyl Cysteine (NAC) surface-conjugated Cds:Mn/ZnS Qdots. Quenching of NAC-Qdots was due to aggregation of Qdots in solution. This aggregation induced fluorescence quenching phenomenon resembles with the self-quenching phenomenon of traditional organic fluorescence dyes at high concentrations. UV-VIS and fluorescence emission spectroscopy data support the interaction and binding of GSH with the NAC-Qdots. Increase in particle size due to GSH induced aggregation of NAC-Qdots was confirmed by the Dynamic Light Scattering (DLS) data.

  20. Samara Probe For Remote Imaging

    NASA Technical Reports Server (NTRS)

    Burke, James D.

    1989-01-01

    Imaging probe descends through atmosphere of planet, obtaining images of ground surface as it travels. Released from aircraft over Earth or from spacecraft over another planet. Body and single wing shaped like samara - winged seed like those of maple trees. Rotates as descends, providing panoramic view of terrain below. Radio image obtained by video camera to aircraft or spacecraft overhead.

  1. In vivo near-infrared fluorescence imaging of FAP-expressing tumors with activatable FAP-targeted, single-chain Fv-immunoliposomes.

    PubMed

    Rüger, Ronny; Tansi, Felista L; Rabenhold, Markus; Steiniger, Frank; Kontermann, Roland E; Fahr, Alfred; Hilger, Ingrid

    2014-07-28

    Molecular and cellular changes that precede the invasive growth of solid tumors include the release of proteolytic enzymes and peptides in the tumor stroma, the recruitment of phagocytic and lymphoid infiltrates and alteration of the extracellular matrix. The reactive tumor stroma consists of a large number of myofibroblasts, characterized by high expression of fibroblast activation protein alpha (FAP). FAP, a type-II transmembrane sialoglycoprotein is an attractive target in diagnosis and therapy of several pathologic disorders especially cancer. In the underlying work, a fluorescence-activatable liposome (fluorescence-quenched during circulation and fluorescence activation upon cellular uptake), bearing specific single-chain Fv fragments directed against FAP (scFv'FAP) was developed, and its potential for use in fluorescence diagnostic imaging of FAP-expressing tumor cells was evaluated by whole body fluorescence imaging. The liposomes termed anti-FAP-IL were prepared via post-insertion of ligand-phospholipid-conjugates into preformed DY-676-COOH-containing liposomes. The anti-FAP-IL revealed a homogeneous size distribution and showed specific interaction and binding with FAP-expressing cells in vitro. The high level of fluorescence quenching of the near-infrared fluorescent dye sequestered in the aqueous interior of the liposomes enables fluorescence imaging exclusively upon uptake and degradation by cells, which results in fluorescence activation. Only FAP-expressing cells were able to take up and activate fluorescence of anti-FAP-IL in vitro. Furthermore, anti-FAP-IL accumulated selectively in FAP-expressing xenograft models in vivo, as demonstrated by blocking experiments using free scFv'FAP. The local tumor fluorescence intensities were in agreement with the intrinsic degree of FAP-expression in different xenograft models. Thus, anti-FAP-IL can serve as a suitable in vivo diagnostic tool for pathological disorders accompanied by high FAP-expression.

  2. Activatable thermo-sensitive ICG encapsulated pluronic nanocapsules for temperature sensitive fluorescence tomography

    NASA Astrophysics Data System (ADS)

    Kwong, Tiffany C.; Nouizi, Farouk; Sampathkumaran, Uma; Zhu, Yue; Alam, Maksudul M.; Gulsen, Gultekin

    2015-03-01

    Fluorescent tomography has been hindered by poor tissue penetration and weak signal which results in poor spatial resolution and quantification accuracy. Recently, it has been reported that activatable temperature responsive fluorescent probes which respond to focused ultrasound heating can improve the resolution and quantification of fluorescent tomography in deep tissue. This has lead to a new imaging modality, "Temperature-modulated fluorescent tomography." This technique relies on activatable thermo-sensitive fluorescent nanocapsules for whose fluorescence quantum efficiency is temperature dependent. Within a 4-5° C temperature range, the fluorescent signal increase more than 10-fold. In this molecular probe, Indocyanine Green (ICG) is encapsulated inside the core of a thermo-reversible pluronic micelle. Here we show the fluorescence response and temperature range of the nanocapsules which have been optimized for a higher temperature range to be used for in vivo animal imaging. We report on the feasibility of these temperature-sensitive reversible nanocapsules for in vivo applications by studying the pharmacokinetics in a subcutaneous mouse tumor model in vivo.

  3. Targeted pH-dependent fluorescent activity-based cathepsin probes.

    PubMed

    Hoogendoorn, Sascha; Habets, Kim L; Passemard, Solène; Kuiper, Johan; van der Marel, Gijsbert A; Florea, Bogdan I; Overkleeft, Herman S

    2011-09-01

    Bifunctional, pH-activatable BODIPY dyes were developed and incorporated in mannose cluster-containing activity-based probes for cysteine proteases. Mannose receptor-dependent uptake of the probes in dendritic cells, followed by trafficking to acidic cellular compartments resulted in fluorescence as seen by live-cell imaging, and subsequent cathepsin inhibition.

  4. Design and Development of Molecular Imaging Probes

    PubMed Central

    Chen, Kai; Chen, Xiaoyuan

    2013-01-01

    Molecular imaging, the visualization, characterization and measurement of biological processes at the cellular, subcellular level, or even molecular level in living subjects, has rapidly gained importance in the dawning era of personalized medicine. Molecular imaging takes advantage of the traditional diagnostic imaging techniques and introduces molecular imaging probes to determine the expression of indicative molecular markers at different stages of diseases and disorders. As a key component of molecular imaging, molecular imaging probe must be able to specifically reach the target of interest in vivo while retaining long enough to be detected. A desirable molecular imaging probe with clinical translation potential is expected to have unique characteristics. Therefore, design and development of molecular imaging probe is frequently a challenging endeavor for medicinal chemists. This review summarizes the general principles of molecular imaging probe design and some fundamental strategies of molecular imaging probe development with a number of illustrative examples. PMID:20388106

  5. Discrete Bimodal Probes for Thrombus Imaging

    PubMed Central

    Uppal, Ritika; Ciesienski, Kate L.; Chonde, Daniel B.; Loving, Galen S.; Caravan, Peter

    2012-01-01

    Here we report a generalizable solid/solution phase strategy for the synthesis of discrete bimodal fibrin-targeted imaging probes. A fibrin-specific peptide was conjugated with two distinct imaging reporters at the C- and N-terminus. In vitro studies demonstrated retention of fibrin affinity and specificity. Imaging studies showed that these probes could detect fibrin over a wide range of probe concentrations by optical, magnetic resonance, and positron emission tomography imaging. PMID:22698259

  6. Mitochondria-targeted Triphenylamine Derivatives Activatable by Two-Photon Excitation for Triggering and Imaging Cell Apoptosis

    PubMed Central

    Chennoufi, Rahima; Bougherara, Houcine; Gagey-Eilstein, Nathalie; Dumat, Blaise; Henry, Etienne; Subra, Frédéric; Bury-Moné, Stéphanie; Mahuteau-Betzer, Florence; Tauc, Patrick; Teulade-Fichou, Marie-Paule; Deprez, Eric

    2016-01-01

    Photodynamic therapy (PDT) leads to cell death by using a combination of a photosensitizer and an external light source for the production of lethal doses of reactive oxygen species (ROS). Since a major limitation of PDT is the poor penetration of UV-visible light in tissues, there is a strong need for organic compounds whose activation is compatible with near-infrared excitation. Triphenylamines (TPAs) are fluorescent compounds, recently shown to efficiently trigger cell death upon visible light irradiation (458 nm), however outside the so-called optical/therapeutic window. Here, we report that TPAs target cytosolic organelles of living cells, mainly mitochondria, triggering a fast apoptosis upon two-photon excitation, thanks to their large two-photon absorption cross-sections in the 760–860 nm range. Direct ROS imaging in the cell context upon multiphoton excitation of TPA and three-color flow cytometric analysis showing phosphatidylserine externalization indicate that TPA photoactivation is primarily related to the mitochondrial apoptotic pathway via ROS production, although significant differences in the time courses of cell death-related events were observed, depending on the compound. TPAs represent a new class of water-soluble organic photosensitizers compatible with direct two-photon excitation, enabling simultaneous multiphoton fluorescence imaging of cell death since a concomitant subcellular TPA re-distribution occurs in apoptotic cells. PMID:26947258

  7. Harnessing the power of cell-penetrating peptides: activatable carriers for targeting systemic delivery of cancer therapeutics and imaging agents.

    PubMed

    MacEwan, Sarah R; Chilkoti, Ashutosh

    2013-01-01

    Targeted delivery of cancer therapeutics and imaging agents aims to enhance the accumulation of these molecules in a solid tumor while avoiding uptake in healthy tissues. Tumor-specific accumulation has been pursued with passive targeting by the enhanced permeability and retention effect, as well as with active targeting strategies. Active targeting is achieved by functionalization of carriers to allow specific interactions between the carrier and the tumor environment. Functionalization of carriers with ligands that specifically interact with overexpressed receptors on cancer cells represents a classic approach to active tumor targeting. Cell-penetrating peptides (CPPs) provide a non-specific and receptor-independent mechanism to enhance cellular uptake that offers an exciting alternative to traditional active targeting approaches. While the non-specificity of CPP-mediated internalization has the intriguing potential to make this approach applicable to a wide range of tumor types, their promiscuity is, however, a significant barrier to their clinical utility for systemically administered applications. Many approaches have been investigated to selectively turn on the function of systemically delivered CPP-functionalized carriers specifically in tumors to achieve targeted delivery of cancer therapeutics and imaging agents.

  8. Imaging probe for tumor malignancy

    NASA Astrophysics Data System (ADS)

    Tanaka, Shotaro; Kizaka-Kondoh, Shinae; Hiraoka, Hasahiro

    2009-02-01

    Solid tumors possess unique microenvironments that are exposed to chronic hypoxic conditions ("tumor hypoxia"). Although more than half a century has passed since it was suggested that tumor hypoxia correlated with poor treatment outcomes and contributed to cancer recurrence, a fundamental solution to this problem has yet to be found. Hypoxia-inducible factor (HIF-1) is the main transcription factor that regulates the cellular response to hypoxia. It induces various genes whose functions are strongly associated with malignant alteration of the entire tumor. The cellular changes induced by HIF-1 are extremely important targets of cancer therapy, particularly in therapy against refractory cancers. Imaging of the HIF-1-active microenvironment is therefore important for cancer therapy. To image HIF-1activity in vivo, we developed a PTD-ODD fusion protein, POHA, which was uniquely labeled with near-infrared fluorescent dye at the C-terminal. POHA has two functional domains: protein transduction domain (PTD) and VHL-mediated protein destruction motif in oxygen-dependent degradation (ODD) domain of the alpha subunit of HIF-1 (HIF-1α). It can therefore be delivered to the entire body and remain stabilized in the HIF-1-active cells. When it was intravenously injected into tumor-bearing mice, a tumor-specific fluorescence signal was detected in the tumor 6 h after the injection. These results suggest that POHA can be used an imaging probe for tumor malignancy.

  9. Methylene blue microbubbles as a model dual-modality contrast agent for ultrasound and activatable photoacoustic imaging.

    PubMed

    Jeon, Mansik; Song, Wentao; Huynh, Elizabeth; Kim, Jungho; Kim, Jeesu; Helfield, Brandon L; Leung, Ben Y C; Goertz, David E; Zheng, Gang; Oh, Jungtaek; Lovell, Jonathan F; Kim, Chulhong

    2014-01-01

    Ultrasound and photoacoustic imaging are highly complementary modalities since both use ultrasonic detection for operation. Increasingly, photoacoustic and ultrasound have been integrated in terms of hardware instrumentation. To generate a broadly accessible dual-modality contrast agent, we generated microbubbles (a standard ultrasound contrast agent) in a solution of methylene blue (a standard photoacoustic dye). This MB2 solution was formed effectively and was optimized as a dual-modality contrast solution. As microbubble concentration increased (with methylene blue concentration constant), photoacoustic signal was attenuated in the MB2 solution. When methylene blue concentration increased (with microbubble concentration held constant), no ultrasonic interference was observed. Using an MB2 solution that strongly attenuated all photoacoustic signal, high powered ultrasound could be used to burst the microbubbles and dramatically enhance photoacoustic contrast (>800-fold increase), providing a new method for spatiotemporal control of photoacoustic signal generation.

  10. A pH-activatable nanoparticle with signal-amplification capabilities for non-invasive imaging of tumour malignancy.

    PubMed

    Mi, Peng; Kokuryo, Daisuke; Cabral, Horacio; Wu, Hailiang; Terada, Yasuko; Saga, Tsuneo; Aoki, Ichio; Nishiyama, Nobuhiro; Kataoka, Kazunori

    2016-08-01

    Engineered nanoparticles that respond to pathophysiological parameters, such as pH or redox potential, have been developed as contrast agents for the magnetic resonance imaging (MRI) of tumours. However, beyond anatomic assessment, contrast agents that can sense these pathological parameters and rapidly amplify their magnetic resonance signals are desirable because they could potentially be used to monitor the biological processes of tumours and improve cancer diagnosis. Here, we report an MRI contrast agent that rapidly amplifies magnetic resonance signals in response to pH. We confined Mn(2+) within pH-sensitive calcium phosphate (CaP) nanoparticles comprising a poly(ethylene glycol) shell. At a low pH, such as in solid tumours, the CaP disintegrates and releases Mn(2+) ions. Binding to proteins increases the relaxivity of Mn(2+) and enhances the contrast. We show that these nanoparticles could rapidly and selectively brighten solid tumours, identify hypoxic regions within the tumour mass and detect invisible millimetre-sized metastatic tumours in the liver. PMID:27183055

  11. A pH-activatable nanoparticle with signal-amplification capabilities for non-invasive imaging of tumour malignancy

    NASA Astrophysics Data System (ADS)

    Mi, Peng; Kokuryo, Daisuke; Cabral, Horacio; Wu, Hailiang; Terada, Yasuko; Saga, Tsuneo; Aoki, Ichio; Nishiyama, Nobuhiro; Kataoka, Kazunori

    2016-08-01

    Engineered nanoparticles that respond to pathophysiological parameters, such as pH or redox potential, have been developed as contrast agents for the magnetic resonance imaging (MRI) of tumours. However, beyond anatomic assessment, contrast agents that can sense these pathological parameters and rapidly amplify their magnetic resonance signals are desirable because they could potentially be used to monitor the biological processes of tumours and improve cancer diagnosis. Here, we report an MRI contrast agent that rapidly amplifies magnetic resonance signals in response to pH. We confined Mn2+ within pH-sensitive calcium phosphate (CaP) nanoparticles comprising a poly(ethylene glycol) shell. At a low pH, such as in solid tumours, the CaP disintegrates and releases Mn2+ ions. Binding to proteins increases the relaxivity of Mn2+ and enhances the contrast. We show that these nanoparticles could rapidly and selectively brighten solid tumours, identify hypoxic regions within the tumour mass and detect invisible millimetre-sized metastatic tumours in the liver.

  12. Further capacitive imaging experiments using modified probes

    NASA Astrophysics Data System (ADS)

    Yin, Xiaokang; Li, Zhen; Yan, An; Li, Wei; Chen, Guoming; Hutchins, David A.

    2016-02-01

    In recent years, capacitive imaging (CI) is growing in popularity within the NDE communities, as it has the potential to test materials and structures for defects that are not easily tested by other techniques. In previous work, The CI technique has been successfully used on a various types of materials, including concrete, glass/carbon fibre composite, steel, etc. In such CI experiments, the probes are normally with symmetric or concentric electrodes etched onto PCBs. In addition to these conventional coplanar PCB probes, modified geometries can be made and they can lead to different applications. A brief overview of these modified probes, including high resolution surface imaging probe, combined CI/eddy current probe, and CI probe using an oscilloscope probe as the sensing electrode, is presented in this work. The potential applications brought by these probes are also discussed.

  13. Rapid and sensitive detection of early esophageal squamous cell carcinoma with fluorescence probe targeting dipeptidylpeptidase IV

    PubMed Central

    Onoyama, Haruna; Kamiya, Mako; Kuriki, Yugo; Komatsu, Toru; Abe, Hiroyuki; Tsuji, Yosuke; Yagi, Koichi; Yamagata, Yukinori; Aikou, Susumu; Nishida, Masato; Mori, Kazuhiko; Yamashita, Hiroharu; Fujishiro, Mitsuhiro; Nomura, Sachiyo; Shimizu, Nobuyuki; Fukayama, Masashi; Koike, Kazuhiko; Urano, Yasuteru; Seto, Yasuyuki

    2016-01-01

    Early detection of esophageal squamous cell carcinoma (ESCC) is an important prognosticator, but is difficult to achieve by conventional endoscopy. Conventional lugol chromoendoscopy and equipment-based image-enhanced endoscopy, such as narrow-band imaging (NBI), have various practical limitations. Since fluorescence-based visualization is considered a promising approach, we aimed to develop an activatable fluorescence probe to visualize ESCCs. First, based on the fact that various aminopeptidase activities are elevated in cancer, we screened freshly resected specimens from patients with a series of aminopeptidase-activatable fluorescence probes. The results indicated that dipeptidylpeptidase IV (DPP-IV) is specifically activated in ESCCs, and would be a suitable molecular target for detection of esophageal cancer. Therefore, we designed, synthesized and characterized a series of DPP-IV-activatable fluorescence probes. When the selected probe was topically sprayed onto endoscopic submucosal dissection (ESD) or surgical specimens, tumors were visualized within 5 min, and when the probe was sprayed on biopsy samples, the sensitivity, specificity and accuracy reached 96.9%, 85.7% and 90.5%. We believe that DPP-IV-targeted activatable fluorescence probes are practically translatable as convenient tools for clinical application to enable rapid and accurate diagnosis of early esophageal cancer during endoscopic or surgical procedures. PMID:27245876

  14. Multifunctional imaging probe based on gadofulleride nanoplatform

    NASA Astrophysics Data System (ADS)

    Zheng, Jun-Peng; Liu, Qiao-Ling; Zhen, Ming-Ming; Jiang, Feng; Shu, Chun-Ying; Jin, Chan; Yang, Yongji; Alhadlaq, Hisham A.; Wang, Chun-Ru

    2012-05-01

    A FAR over-expressed tumor targeting multifunctional imaging probe has been fabricated based on gadofulleride nanoplatform. The combination of highly efficient MRI contrast enhancement and sensitive fluorescence imaging along with the preferential uptake toward FAR tumor cells suggest that the obtained multifunctional imaging probe possesses complementary capabilities for anatomical resolution and detection sensitivity.A FAR over-expressed tumor targeting multifunctional imaging probe has been fabricated based on gadofulleride nanoplatform. The combination of highly efficient MRI contrast enhancement and sensitive fluorescence imaging along with the preferential uptake toward FAR tumor cells suggest that the obtained multifunctional imaging probe possesses complementary capabilities for anatomical resolution and detection sensitivity. Electronic supplementary information (ESI) available: Materials, instruments and methods, synthesis details, XPS characterization for estimation of average molecular formula, evaluation of conjugated FA and FITC ratio, zeta potential and fluorescent images. See DOI: 10.1039/c2nr30836c

  15. Techniques for Molecular Imaging Probe Design

    PubMed Central

    Reynolds, Fred; Kelly, Kimberly A.

    2011-01-01

    Molecular imaging allows clinicians to visualize disease specific molecules, thereby providing relevant information in the diagnosis and treatment of patients. With advances in genomics and proteomics and underlying mechanisms of disease pathology, the number of targets identified has significantly outpaced the number of developed molecular imaging probes. There has been a concerted effort to bridge this gap with multidisciplinary efforts in chemistry, proteomics, physics, material science, and biology; all essential to progress in molecular imaging probe development. In this review, we will discuss target selection, screening techniques and probe optimization with the aim of developing clinically relevant molecularly targeted imaging agents. PMID:22201532

  16. Molecular Imaging Probe Development using Microfluidics

    PubMed Central

    Liu, Kan; Wang, Ming-Wei; Lin, Wei-Yu; Phung, Duy Linh; Girgis, Mark D.; Wu, Anna M.; Tomlinson, James S.; Shen, Clifton K.-F.

    2012-01-01

    In this manuscript, we review the latest advancement of microfluidics in molecular imaging probe development. Due to increasing needs for medical imaging, high demand for many types of molecular imaging probes will have to be met by exploiting novel chemistry/radiochemistry and engineering technologies to improve the production and development of suitable probes. The microfluidic-based probe synthesis is currently attracting a great deal of interest because of their potential to deliver many advantages over conventional systems. Numerous chemical reactions have been successfully performed in micro-reactors and the results convincingly demonstrate with great benefits to aid synthetic procedures, such as purer products, higher yields, shorter reaction times compared to the corresponding batch/macroscale reactions, and more benign reaction conditions. Several ‘proof-of-principle’ examples of molecular imaging probe syntheses using microfluidics, along with basics of device architecture and operation, and their potential limitations are discussed here. PMID:22977436

  17. Advanced ultrasound probes for medical imaging

    NASA Astrophysics Data System (ADS)

    Wildes, Douglas G.; Smith, L. Scott

    2012-05-01

    New medical ultrasound probe architectures and materials build upon established 1D phased array technology and provide improved imaging performance and clinical value. Technologies reviewed include 1.25D and 1.5D arrays for elevation slice thickness control; electro-mechanical and 2D array probes for real-time 3D imaging; catheter probes for imaging during minimally-invasive procedures; single-crystal piezoelectric materials for greater frequency bandwidth; and cMUT arrays using silicon MEMS in place of piezo materials.

  18. Design and study of activatable ("OFF/ON") quantum dots (Qdots): ligand selection for Qdot surface modification for controlling Qdot fluorescence quenching and restoration

    NASA Astrophysics Data System (ADS)

    Teblum, Andrew; Basumallick, Srijita; Shah, Rikhav; Mitra, Rajendra N.; Banerjee, Subhash; Santra, Swadeshmukul

    2012-03-01

    We report design and synthesis of a series of activatable "OFF/ON" CdS:Mn/ZnS quantum dot (Qdot) based sensing probes. The Qdot "OFF" state represent the "quenched state" where the Qdot fluorescence is quenched by ligands attached to Qdot surface. Fluorescence quenching is likely due to ligand assisted electron transfer process. Qdot fluorescence is restored when the electron transfer process is stopped. Using this activatable Qdots, we have successfully demonstrated usefulness of these Qdot probes for reliable detection of toxic cadmium ions in solution, selective detection of glutathione and sensitive detection of intracellular cancer drug release event. In this paper, we will discuss a simple but robust method of making water-soluble CdS:Mn/ZnS Qdots at the room-temperature. Two different water-soluble biomolecules, the N-acetyl cysteine (NAC) and the glutathione (GSH) were used as surface coating ligands. This is a singlestep, one-pot synthesis where the Qdot nanocrystals were grown in the presence of the biomolecules. These Qdots were characterized by fluorescence spectroscopy. Stability of the GSH coated Qdots and the NAC coated Qdots were studied by treating with ethylenediaminetetraacetic acid (EDTA, a strong chelating agent for Zn and Cd ions). Our results show that fluorescence properties of Qdots are affected by the type of surface coated ligands. In comparison to the GSH coated Qdots, the NAC coated Qdots show broad but strong emission towards near infra-red region. When treated with EDTA, fluorescence property of the GSH coated Qdot was affected less than the NAC coated Qdots. This preliminary study shows that NAC coated Qdots could potentially be used to develop activatable ("OFF/ON") probes for potential deep-tissue imaging applications. Similarly, the GSH coated Qdots could be applied for probing desired analytes or for bioimaging purposes in environmentally harsh conditions.

  19. Protein-based tumor molecular imaging probes

    PubMed Central

    Lin, Xin; Xie, Jin

    2013-01-01

    Molecular imaging is an emerging discipline which plays critical roles in diagnosis and therapeutics. It visualizes and quantifies markers that are aberrantly expressed during the disease origin and development. Protein molecules remain to be one major class of imaging probes, and the option has been widely diversified due to the recent advances in protein engineering techniques. Antibodies are part of the immunosystem which interact with target antigens with high specificity and affinity. They have long been investigated as imaging probes and were coupled with imaging motifs such as radioisotopes for that purpose. However, the relatively large size of antibodies leads to a half-life that is too long for common imaging purposes. Besides, it may also cause a poor tissue penetration rate and thus compromise some medical applications. It is under this context that various engineered protein probes, essentially antibody fragments, protein scaffolds, and natural ligands have been developed. Compared to intact antibodies, they possess more compact size, shorter clearance time, and better tumor penetration. One major challenge of using protein probes in molecular imaging is the affected biological activity resulted from random labeling. Site-specific modification, however, allows conjugation happening in a stoichiometric fashion with little perturbation of protein activity. The present review will discuss protein-based probes with focus on their application and related site-specific conjugation strategies in tumor imaging. PMID:20232092

  20. Ratiometric imaging of pH probes.

    PubMed

    Grillo-Hill, Bree K; Webb, Bradley A; Barber, Diane L

    2014-01-01

    Measurement of intracellular pH can be readily accomplished using tools and methods described in this chapter. We present a discussion of technical considerations of various ratiometric pH-sensitive probes including dyes and genetically encoded sensors. These probes can be used to measure pH across physical scales from macroscopic whole-mount tissues down to organelles and subcellular domains. We describe protocols for loading pH-sensitive probes into single cells or tissues and discuss ratiometric image acquisition and analysis.

  1. Luminescent probes for optical in vivo imaging

    NASA Astrophysics Data System (ADS)

    Texier, Isabelle; Josserand, Veronique; Garanger, Elisabeth; Razkin, Jesus; Jin, Zhaohui; Dumy, Pascal; Favrot, Marie; Boturyn, Didier; Coll, Jean-Luc

    2005-04-01

    Going along with instrumental development for small animal fluorescence in vivo imaging, we are developing molecular fluorescent probes, especially for tumor targeting. Several criteria have to be taken into account for the optimization of the luminescent label. It should be adapted to the in vivo imaging optical conditions : red-shifted absorption and emission, limited overlap between absorption and emission for a good signal filtering, optimized luminescence quantum yield, limited photo-bleaching. Moreover, the whole probe should fulfill the biological requirements for in vivo labeling : adapted blood-time circulation, biological conditions compatibility, low toxicity. We here demonstrate the ability of the imaging fluorescence set-up developed in LETI to image the bio-distribution of molecular probes on short times after injection. Targeting with Cy5 labeled holo-transferrin of subcutaneous TS/Apc (angiogenic murine breast carcinoma model) or IGROV1 (human ovarian cancer) tumors was achieved. Differences in the kinetics of the protein uptake by the tumors were evidenced. IGROV1 internal metastatic nodes implanted in the peritoneal cavity could be detected in nude mice. However, targeted metastatic nodes in lung cancer could only be imaged after dissection of the mouse. These results validate our fluorescence imaging set-up and the use of Cy5 as a luminescent label. New fluorescent probes based on this dye and a molecular delivery template (the RAFT molecule) can thus be envisioned.

  2. Lymphatic Imaging: Focus on Imaging Probes

    PubMed Central

    Niu, Gang; Chen, Xiaoyuan

    2015-01-01

    In view of the importance of sentinel lymph nodes (SLNs) in tumor staging and patient management, sensitive and accurate imaging of SLNs has been intensively explored. Along with the advance of the imaging technology, various contrast agents have been developed for lymphatic imaging. In this review, the lymph node imaging agents were summarized into three groups: tumor targeting agents, lymphatic targeting agents and lymphatic mapping agents. Tumor targeting agents are used to detect metastatic tumor tissue within LNs, lymphatic targeting agents aim to visualize lymphatic vessels and lymphangionesis, while lymphatic mapping agents are mainly for SLN detection during surgery after local administration. Coupled with various signal emitters, these imaging agents work with single or multiple imaging modalities to provide a valuable way to evaluate the location and metastatic status of SLNs. PMID:25897334

  3. Chemically Activatable Alkyne Tag for Low pH-Enhanced Molecular Labeling on Living Cells.

    PubMed

    Yamaguchi, Satoshi; Ura, Manami; Izuta, Shin; Okamoto, Akimitsu

    2016-09-21

    Stimuli-responsive "activatable" reactive tags are applicable to selective labeling of biomolecules in a defined area or environment in living systems, yielding new insights into cellular processes through molecular imaging and fishing. Here, we developed a chemically activatable alkyne tag that can be incorporated into biological molecules and labeled with azide-tagged functional molecules through the alkyne-azide cycloaddition "click" reaction after chemical activation. Formation of the alkyne tag from the precursor moiety was confirmed to proceed in physiological aqueous media and was particularly enhanced under mildly acidic pH. The tag was successfully applied to low-pH sensitive labeling of a cholesterol analogue with azide-tagged biotin on living mammalian cells. Our results provided proof of principle that the present activatable alkyne tag can be used as a tool to selectively analyze molecules of interest in low-pH regions in living systems. PMID:27526276

  4. Scanning probe image wizard: a toolbox for automated scanning probe microscopy data analysis.

    PubMed

    Stirling, Julian; Woolley, Richard A J; Moriarty, Philip

    2013-11-01

    We describe SPIW (scanning probe image wizard), a new image processing toolbox for SPM (scanning probe microscope) images. SPIW can be used to automate many aspects of SPM data analysis, even for images with surface contamination and step edges present. Specialised routines are available for images with atomic or molecular resolution to improve image visualisation and generate statistical data on surface structure.

  5. Scanning probe image wizard: A toolbox for automated scanning probe microscopy data analysis

    NASA Astrophysics Data System (ADS)

    Stirling, Julian; Woolley, Richard A. J.; Moriarty, Philip

    2013-11-01

    We describe SPIW (scanning probe image wizard), a new image processing toolbox for SPM (scanning probe microscope) images. SPIW can be used to automate many aspects of SPM data analysis, even for images with surface contamination and step edges present. Specialised routines are available for images with atomic or molecular resolution to improve image visualisation and generate statistical data on surface structure.

  6. Errors Associated With Measurements from Imaging Probes

    NASA Astrophysics Data System (ADS)

    Heymsfield, A.; Bansemer, A.

    2015-12-01

    Imaging probes, collecting data on particles from about 20 or 50 microns to several centimeters, are the probes that have been collecting data on the droplet and ice microphysics for more than 40 years. During that period, a number of problems associated with the measurements have been identified, including questions about the depth of field of particles within the probes' sample volume, and ice shattering, among others, have been identified. Many different software packages have been developed to process and interpret the data, leading to differences in the particle size distributions and estimates of the extinction, ice water content and radar reflectivity obtained from the same data. Given the numerous complications associated with imaging probe data, we have developed an optical array probe simulation package to explore the errors that can be expected with actual data. We simulate full particle size distributions with known properties, and then process the data with the same software that is used to process real-life data. We show that there are significant errors in the retrieved particle size distributions as well as derived parameters such as liquid/ice water content and total number concentration. Furthermore, the nature of these errors change as a function of the shape of the simulated size distribution and the physical and electronic characteristics of the instrument. We will introduce some methods to improve the retrieval of particle size distributions from real-life data.

  7. Molecular imaging probe development: a chemistry perspective

    PubMed Central

    Nolting, Donald D; Nickels, Michael L; Guo, Ning; Pham, Wellington

    2012-01-01

    Molecular imaging is an attractive modality that has been widely employed in many aspects of biomedical research; especially those aimed at the early detection of diseases such as cancer, inflammation and neurodegenerative disorders. The field emerged in response to a new research paradigm in healthcare that seeks to integrate detection capabilities for the prediction and prevention of diseases. This approach made a distinct impact in biomedical research as it enabled researchers to leverage the capabilities of molecular imaging probes to visualize a targeted molecular event non-invasively, repeatedly and continuously in a living system. In addition, since such probes are inherently compact, robust, and amenable to high-throughput production, these probes could potentially facilitate screening of preclinical drug discovery, therapeutic assessment and validation of disease biomarkers. They could also be useful in drug discovery and safety evaluations. In this review, major trends in the chemical synthesis and development of positron emission tomography (PET), optical and magnetic resonance imaging (MRI) probes are discussed. PMID:22943038

  8. Design of Targeted Cardiovascular Molecular Imaging Probes

    PubMed Central

    Anderson, Carolyn J.; Bulte, Jeff W.M.; Chen, Kai; Chen, Xiaoyuan; Khaw, Ban-An; Shokeen, Monica; Wooley, Karen L.; VanBrocklin, Henry F.

    2013-01-01

    Molecular imaging relies on the development of sensitive and specific probes coupled with imaging hardware and software to provide information about the molecular status of a disease and its response to therapy, which are important aspects of disease management. As genomic and proteomic information from a variety of cardiovascular diseases becomes available, new cellular and molecular targets will provide an imaging readout of fundamental disease processes. A review of the development and application of several cardiovascular probes is presented here. Strategies for labeling cells with superparamagnetic iron oxide nanoparticles enable monitoring of the delivery of stem cell therapies. Small molecules and biologics (e.g., proteins and antibodies) with high affinity and specificity for cell surface receptors or cellular proteins as well as enzyme substrates or inhibitors may be labeled with single-photon–emitting or positron-emitting isotopes for nuclear molecular imaging applications. Labeling of bispecific antibodies with single-photon–emitting isotopes coupled with a pretargeting strategy may be used to enhance signal accumulation in small lesions. Emerging nanomaterials will provide platforms that have various sizes and structures and that may be used to develop multimeric, multimodal molecular imaging agents to probe one or more targets simultaneously. These platforms may be chemically manipulated to afford molecules with specific targeting and clearance properties. These examples of molecular imaging probes are characteristic of the multidisciplinary nature of the extraction of advanced biochemical information that will enhance diagnostic evaluation and drug development and predict clinical outcomes, fulfilling the promise of personalized medicine and improved patient care. PMID:20395345

  9. An image registration based ultrasound probe calibration

    NASA Astrophysics Data System (ADS)

    Li, Xin; Kumar, Dinesh; Sarkar, Saradwata; Narayanan, Ram

    2012-02-01

    Reconstructed 3D ultrasound of prostate gland finds application in several medical areas such as image guided biopsy, therapy planning and dose delivery. In our application, we use an end-fire probe rotated about its axis to acquire a sequence of rotational slices to reconstruct 3D TRUS (Transrectal Ultrasound) image. The image acquisition system consists of an ultrasound transducer situated on a cradle directly attached to a rotational sensor. However, due to system tolerances, axis of probe does not align exactly with the designed axis of rotation resulting in artifacts in the 3D reconstructed ultrasound volume. We present a rigid registration based automatic probe calibration approach. The method uses a sequence of phantom images, each pair acquired at angular separation of 180 degrees and registers corresponding image pairs to compute the deviation from designed axis. A modified shadow removal algorithm is applied for preprocessing. An attribute vector is constructed from image intensity and a speckle-insensitive information-theoretic feature. We compare registration between the presented method and expert-corrected images in 16 prostate phantom scans. Images were acquired at multiple resolutions, and different misalignment settings from two ultrasound machines. Screenshots from 3D reconstruction are shown before and after misalignment correction. Registration parameters from automatic and manual correction were found to be in good agreement. Average absolute differences of translation and rotation between automatic and manual methods were 0.27 mm and 0.65 degree, respectively. The registration parameters also showed lower variability for automatic registration (pooled standard deviation σtranslation = 0.50 mm, σrotation = 0.52 degree) compared to the manual approach (pooled standard deviation σtranslation = 0.62 mm, σrotation = 0.78 degree).

  10. Thrombin-activatable fibrinolysis inhibitor.

    PubMed

    Marx, Pauline F

    2004-09-01

    The coagulation system is a potent mechanism that prevents blood loss after vascular injury. It consists of a number of linked enzymatic reactions resulting in thrombin generation. Thrombin converts soluble fibrinogen into a fibrin clot. The clot is subsequently removed by the fibrinolytic system upon wound healing. Thrombin-activatable fibrinolysis inhibitor (TAFI), which is identical to the previously identified proteins procarboxypeptidase B, R, and U, forms a link between blood coagulation and fibrinolysis. TAFI circulates as an inactive proenzyme in the bloodstream, and becomes activated during blood clotting. The active form, TAFIa, inhibits fibrinolysis by cleaving off C-terminal lysine residues from partially degraded fibrin that stimulates the tissue-type plasminogen activator-mediated conversion of plasminogen to plasmin. Consequently, removal of these lysines leads to less plasmin formation and subsequently to protection of the fibrin clot from break down. Moreover, TAFI may also play a role in other processes such as, inflammation and tissue repair. In this review, recent developments in TAFI research are discussed. PMID:15379716

  11. Molecular Probes for Fluorescence Lifetime Imaging

    PubMed Central

    Sarder, Pinaki; Maji, Dolonchampa; Achilefu, Samuel

    2015-01-01

    Visualization of biological processes and pathologic conditions at the cellular and tissue levels largely rely on the use of fluorescence intensity signals from fluorophores or their bioconjugates. To overcome the concentration dependency of intensity measurements, evaluate subtle molecular interactions, and determine biochemical status of intracellular or extracellular microenvironments, fluorescence lifetime (FLT) imaging has emerged as a reliable imaging method complementary to intensity measurements. Driven by a wide variety of dyes exhibiting stable or environment-responsive FLTs, information multiplexing can be readily accomplished without the need for ratiometric spectral imaging. With knowledge of the fluorescent states of the molecules, it is entirely possible to predict the functional status of biomolecules or microevironment of cells. Whereas the use of FLT spectroscopy and microscopy in biological studies is now well established, in vivo imaging of biological processes based on FLT imaging techniques is still evolving. This review summarizes recent advances in the application of the FLT of molecular probes for imaging cells and small animal models of human diseases. It also highlights some challenges that continue to limit the full realization of the potential of using FLT molecular probes to address diverse biological problems, and outlines areas of potential high impact in the future. PMID:25961514

  12. Multimode-Optical-Fiber Imaging Probe

    NASA Technical Reports Server (NTRS)

    Jackson, Deborah

    1999-01-01

    Currently, endoscopic surgery uses single-mode fiber-bundles to obtain in vivo image information inside the orifices of the body. This limits their use to the larger natural orifices and to surgical procedures where there is plenty of room for manipulation. The knee joint, for example, can be easily viewed with a fiber optic viewer, but joints in the finger cannot. However, there are a host of smaller orifices where fiber endoscopy would play an important role if a cost effective fiber probe were developed with small enough dimensions (less than or equal to 250 microns). Examples of beneficiaries of micro-endoscopes are the treatment of the Eustatian tube of the middle ear, the breast ducts, tear ducts, coronary arteries, fallopian tubes, as well as the treatment of salivary duct parotid disease, and the neuro endoscopy of the ventricles and spinal canal. This work describes an approach for recovering images from tightly confined spaces using multimode. The concept draws upon earlier works that concentrated on image recovery after two-way transmission through a multimode fiber as well as work that demonstrated the recovery of images after one-way transmission through a multimode fiber. Both relied on generating a phase conjugated wavefront, which was predistorted with the characteristics of the fiber. The approach described here also relies on generating a phase conjugated wavefront, but utilizes two fibers to capture the image at some intermediate point (accessible by the fibers, but which is otherwise visually inaccessible).

  13. Full tip imaging in atom probe tomography.

    PubMed

    Du, Sichao; Burgess, Timothy; Loi, Shyeh Tjing; Gault, Baptiste; Gao, Qiang; Bao, Peite; Li, Li; Cui, Xiangyuan; Kong Yeoh, Wai; Tan, Hark Hoe; Jagadish, Chennupati; Ringer, Simon P; Zheng, Rongkun

    2013-01-01

    Atom probe tomography (APT) is capable of simultaneously revealing the chemical identities and three dimensional positions of individual atoms within a needle-shaped specimen, but suffers from a limited field-of-view (FOV), i.e., only the core of the specimen is effectively detected. Therefore, the capacity to analyze the full tip is crucial and much desired in cases that the shell of the specimen is also the region of interest. In this paper, we demonstrate that, in the analysis of III-V nanowires epitaxially grown from a substrate, the presence of the flat substrate positioned only micrometers away from the analyzed tip apex alters the field distribution and ion trajectories, which provides extra image compression that allows for the analysis of the entire specimen. An array of experimental results, including field desorption maps, elemental distributions, and crystallographic features clearly demonstrate the fact that the whole tip has been imaged, which is confirmed by electrostatic simulations.

  14. Optical brush: Imaging through permuted probes.

    PubMed

    Heshmat, Barmak; Lee, Ik Hyun; Raskar, Ramesh

    2016-01-01

    The combination of computational techniques and ultrafast imaging have enabled sensing through unconventional settings such as around corners, and through diffusive media. We exploit time of flight (ToF) measurements to enable a flexible interface for imaging through permuted set of fibers. The fibers are randomly distributed in the scene and are packed on the camera end, thus making a brush-like structure. The scene is illuminated by two off-axis optical pulses. Temporal signatures of fiber tips in the scene are used to localize each fiber. Finally, by combining the position and measured intensity of each fiber, the original input is reconstructed. Unlike conventional fiber bundles with packed set of fibers that are limited by a narrow field of view (FOV), lack of flexibility, and extended coaxial precalibration, the proposed optical brush is flexible and uses off-axis calibration method based on ToF. The enabled brush form can couple to other types of ToF imaging systems. This can impact probe-based applications such as, endoscopy, tomography, and industrial imaging and sensing. PMID:26868954

  15. Bioorthogonal probes for imaging sterols in cells.

    PubMed

    Jao, Cindy Y; Nedelcu, Daniel; Lopez, Lyle V; Samarakoon, Thilani N; Welti, Ruth; Salic, Adrian

    2015-03-01

    Cholesterol is a fundamental lipid component of eukaryotic membranes and a precursor of potent signaling molecules, such as oxysterols and steroid hormones. Cholesterol and oxysterols are also essential for Hedgehog signaling, a pathway critical in embryogenesis and cancer. Despite their importance, the use of imaging sterols in cells is currently very limited. We introduce a robust and versatile method for sterol microscopy based on C19 alkyne cholesterol and oxysterol analogues. These sterol analogues are fully functional; they rescue growth of cholesterol auxotrophic cells and faithfully recapitulate the multiple roles that sterols play in Hedgehog signal transduction. Alkyne sterol analogues incorporate efficiently into cellular membranes and can be imaged with high resolution after copper(I)-catalyzed azide-alkyne cycloaddition reaction with fluorescent azides. We demonstrate the use of alkyne sterol probes for visualizing the subcellular distribution of cholesterol and for two-color imaging of sterols and choline phospholipids. Our imaging strategy should be broadly applicable to studying the role of sterols in normal physiology and disease.

  16. Optical brush: Imaging through permuted probes

    PubMed Central

    Heshmat, Barmak; Lee, Ik Hyun; Raskar, Ramesh

    2016-01-01

    The combination of computational techniques and ultrafast imaging have enabled sensing through unconventional settings such as around corners, and through diffusive media. We exploit time of flight (ToF) measurements to enable a flexible interface for imaging through permuted set of fibers. The fibers are randomly distributed in the scene and are packed on the camera end, thus making a brush-like structure. The scene is illuminated by two off-axis optical pulses. Temporal signatures of fiber tips in the scene are used to localize each fiber. Finally, by combining the position and measured intensity of each fiber, the original input is reconstructed. Unlike conventional fiber bundles with packed set of fibers that are limited by a narrow field of view (FOV), lack of flexibility, and extended coaxial precalibration, the proposed optical brush is flexible and uses off-axis calibration method based on ToF. The enabled brush form can couple to other types of ToF imaging systems. This can impact probe-based applications such as, endoscopy, tomography, and industrial imaging and sensing. PMID:26868954

  17. Photoacoustic lifetime imaging and its biomedical applications

    NASA Astrophysics Data System (ADS)

    Shao, Qi

    Even though oxygen plays a crucial role in body function and cancer biology, methods of measuring oxygen level in tissue are all limited. The current gold standard relies on an invasive electrode for only single-point reading at a time. The photoacoustic lifetime imaging (PALI) approach overcomes these major limitations by applying photoacoustic probing to oxygen-sensitive optical transient absorption. The capability of assessing oxygen distribution is demonstrated by imaging tumor hypoxia in a small animal model, and monitoring changes of tissue oxygen induced by external modulations. Proposed applications of this imaging technique includes imaging-guided photodynamic therapy (PDT) and activatable probes for molecular imaging.

  18. Multimode-Optical-Fiber Imaging Probe

    NASA Technical Reports Server (NTRS)

    Jackson, Deborah

    2000-01-01

    Currently, endoscopic surgery uses single-mode fiber-bundles to obtain in vivo image information inside orifices of the body. This limits their use to the larger natural bodily orifices and to surgical procedures where there is plenty of room for manipulation. The knee joint, for example can be easily viewed with a fiber optic viewer, but joints in the finger cannot. However, there are a host of smaller orifices where fiber endoscopy would play an important role if a cost effective fiber probe were developed with small enough dimensions (< 250 microns). Examples of beneficiaries of micro-endoscopes are the treatment of the Eustatian tube of the middle ear, the breast ducts, tear ducts, coronary arteries, fallopian tubes, as well as the treatment of salivary duct parotid disease, and the neuro endoscopy of the ventricles and spinal canal. To solve this problem, this work describes an approach for recovering images from. tightly confined spaces using multimode fibers and analytically demonstrates that the concept is sound. The proof of concept draws upon earlier works that concentrated on image recovery after two-way transmission through a multimode fiber as well as work that demonstrated the recovery of images after one-way transmission through a multimode fiber. Both relied on generating a phase conjugated wavefront which was predistorted with the characteristics of the fiber. The described approach also relies on generating a phase conjugated wavefront, but utilizes two fibers to capture the image at some intermediate point (accessible by the fibers, but which is otherwise visually unaccessible).

  19. Imaging probe for breast cancer localization

    NASA Astrophysics Data System (ADS)

    Soluri, A.; Scafè, R.; Capoccetti, F.; Burgio, N.; Schiaratura, A.; Pani, R.; Pellegrini, R.; Cinti, M. N.; Mechella, M.; Amanti, A.; David, V.; Scopinaro, F.

    2003-01-01

    High spatial resolution, small Field Of View (FOV), fully portable scintillation cameras are lower cost and obviously lower weight than large FOV, not transportable Anger gamma cameras. Portable cameras allow easy transfer of the detector, thus of radioisotope imaging, where the bioptical procedure takes place. In this paper we describe a preliminary experience on radionuclide Breast Cancer (BC) imaging with a 22.8×22.8 mm 2 FOV minicamera, already used by our group for sentinel node detection with the name of Imaging Probe (IP). In this work IP BC detection was performed with the aim of guiding biopsy, in particular open biopsy, or to help or modify fine needle or needle addressing when main driving method was echography or digital radiography. The IP prototype weight was about 1 kg. This small scintillation camera is based on the compact Position Sensitive Photomultiplier Tube Hamamatsu R7600-00-C8, coupled to a CsI(Tl) scintillation array 2.6×2.6×5.0 mm 3 crystal-pixel size. Spatial resolution of the IP was 2.5 mm Full-Width at Half-Maximum at laboratory tests. IP was provided with acquisition software allowing quick change of pixels number on the computer acquisition frame and an on-line image-smoothing program. Both these programs were developed in order to allow nuclear physicians to quickly get target source when the patient was anesthetized in the operator room, with sterile conditions. 99mTc Sestamibi (MIBI) was injected at the dose of 740 MBq 1 h before imaging and biopsy to 14 patients with suspicious or known BC. Scintigraphic images were acquired before and after biopsy in each patient. Operator was allowed to take into account scintigraphic images as well as previously performed X-ray mammograms and echographies. High-resolution IP images were able to guide biopsy toward cancer or washout zones of the cancer, that are thought to be chemoresistant in 7 patients out of 10. Four patients, in whom IP and MIBI were not able to guide biopsy, did not show

  20. Stereoselective synthesis of light-activatable perfluorophenylazide-conjugated carbohydrates for glycoarray fabrication and evaluation of structural effects on protein binding by SPR imaging†

    PubMed Central

    Deng, Lingquan; Norberg, Oscar; Uppalapati, Suji; Yan, Mingdi; Ramström, Olof

    2014-01-01

    A series of light-activatable perfluorophenylazide (PFPA)-conjugated carbohydrate structures have been synthesized and applied to glycoarray fabrication. The glycoconjugates were structurally varied with respect to anomeric attachment, S-, and O-linked carbohydrates, respectively, as well as linker structure and length. Efficient stereoselective synthetic routes were developed, leading to the formation of the PFPA-conjugated structures in good yields over few steps. The use of glycosyl thiols as donors proved especially efficient and provided the final compounds in up to 70% total yield with high anomeric purities. PFPA-based photochemistry was subsequently used to generate carbohydrate arrays on a polymeric surface, and surface plasmon resonance imaging (SPRi) was applied for evaluation of carbohydrate-protein interactions using the plant lectin Concanavalin A (Con A) as a probe. The results indicate better performance and equal efficiency of S- and O-linked structures with intermediate linker length. PMID:21423935

  1. Correction of nonlinear lateral distortions of scanning probe microscopy images.

    PubMed

    Schnedler, M; Weidlich, P H; Portz, V; Weber, D; Dunin-Borkowski, R E; Ebert, Ph

    2014-01-01

    A methodology for the correction of scanning probe microscopy image distortions is demonstrated. It is based on the determination of displacement vectors from the measurement of a calibration sample. By moving the pixels of the distorted scanning probe microscopy image along the displacement vectors an almost complete correction of the nonlinear, time independent distortions is achieved. PMID:24013615

  2. Preparation of neutron-activatable holmium nanoparticles for the treatment of ovarian cancer metastases.

    PubMed

    Di Pasqua, Anthony J; Huckle, James E; Kim, Jin-Ki; Chung, Younjee; Wang, Andrew Z; Jay, Michael; Lu, Xiuling

    2012-04-10

    Nanoparticles containing stable holmium ((165) Ho) are prepared by nanotemplate engineering and subsequently irradiated in a neutron flux to yield (166) Ho, a beta-emitting radiotherapeutic isotope. After intraperitoneal injection to mice bearing SKOV-3 ovarian tumors, significant tumor accumulation of the (166) Ho-nanoparticles is observed by SPECT imaging indicating the potential of these neutron activatable nanoparticles for internal radiation therapy of ovarian cancer metastases.

  3. Versatile robotic probe calibration for position tracking in ultrasound imaging

    NASA Astrophysics Data System (ADS)

    Eirik Bø, Lars; Fagertun Hofstad, Erlend; Lindseth, Frank; Hernes, Toril A. N.

    2015-05-01

    Within the field of ultrasound-guided procedures, there are a number of methods for ultrasound probe calibration. While these methods are usually developed for a specific probe, they are in principle easily adapted to other probes. In practice, however, the adaptation often proves tedious and this is impractical in a research setting, where new probes are tested regularly. Therefore, we developed a method which can be applied to a large variety of probes without adaptation. The method used a robot arm to move a plastic sphere submerged in water through the ultrasound image plane, providing a slow and precise movement. The sphere was then segmented from the recorded ultrasound images using a MATLAB programme and the calibration matrix was computed based on this segmentation in combination with tracking information. The method was tested on three very different probes demonstrating both great versatility and high accuracy.

  4. Versatile robotic probe calibration for position tracking in ultrasound imaging.

    PubMed

    Bø, Lars Eirik; Hofstad, Erlend Fagertun; Lindseth, Frank; Hernes, Toril A N

    2015-05-01

    Within the field of ultrasound-guided procedures, there are a number of methods for ultrasound probe calibration. While these methods are usually developed for a specific probe, they are in principle easily adapted to other probes. In practice, however, the adaptation often proves tedious and this is impractical in a research setting, where new probes are tested regularly. Therefore, we developed a method which can be applied to a large variety of probes without adaptation. The method used a robot arm to move a plastic sphere submerged in water through the ultrasound image plane, providing a slow and precise movement. The sphere was then segmented from the recorded ultrasound images using a MATLAB programme and the calibration matrix was computed based on this segmentation in combination with tracking information. The method was tested on three very different probes demonstrating both great versatility and high accuracy. PMID:25855886

  5. Molecular probes for the in vivo imaging of cancer

    PubMed Central

    Alford, Raphael; Ogawa, Mikako; Choyke, Peter L.

    2012-01-01

    Advancements in medical imaging have brought about unprecedented changes in the in vivo assessment of cancer. Positron emission tomography, single photon emission computed tomography, optical imaging, and magnetic resonance imaging are the primary tools being developed for oncologic imaging. These techniques may still be in their infancy, as recently developed chemical molecular probes for each modality have improved in vivo characterization of physiologic and molecular characteristics. Herein, we discuss advances in these imaging techniques, and focus on the major design strategies with which molecular probes are being developed. PMID:19823742

  6. Carbon nanotube scanning probe for imaging in aqueous environment

    NASA Technical Reports Server (NTRS)

    Stevens, Ramsey M.; Nguyen, Cattien V.; Meyyappan, M.

    2004-01-01

    Carbon nanotubes (CNTs) used as a probe for scanning probe microscopy has become one of the many potential usages of CNTs that is finding real applications in scientific research and industrial communities. It has been proposed that the unique mechanical buckling properties of the CNT would lessen the imaging force exerted on the sample and, thus, make CNT scanning probes ideal for imaging soft materials, including biological samples in liquid environments. The hydrophobic nature of the CNT graphitic sidewall is clearly chemically incompatible with the aqueous solution requirements in some biological imaging applications. In this paper, we present electron micrograph results demonstrating the instability of CNT scanning probes when submerged in aqueous solution. Moreover, we also introduce a novel approach to resolve this chemical incompatibility problem. By coating the CNT probe with ethylenediamine, thus rendering the CNT probe less hydrophobic, we demonstrate the liquid imaging capability of treated CNT probes. Experimental data for imaging in aqueous solutions are presented, which include an ultrathin Ir film and DNA molecules on a mica surface.

  7. Probe and object function reconstruction in incoherent stem imaging

    SciTech Connect

    Nellist, P.D.; Pennycook, S.J.

    1996-09-01

    Using the phase-object approximation it is shown how an annular dark- field (ADF) detector in a scanning transmission electron microscope (STEM) leads to an image which can be described by an incoherent model. The point spread function is found to be simply the illuminating probe intensity. An important consequence of this is that there is no phase problem in the imaging process, which allows various image processing methods to be applied directly to the image intensity data. Using an image of a GaAs<110>, the probe intensity profile is reconstructed, confirming the existence of a 1.3 {Angstrom} probe in a 300kV STEM. It is shown that simply deconvolving this reconstructed probe from the image data does not improve its interpretability because the dominant effects of the imaging process arise simply from the restricted resolution of the microscope. However, use of the reconstructed probe in a maximum entropy reconstruction is demonstrated, which allows information beyond the resolution limit to be restored and does allow improved image interpretation.

  8. Imaging of endogenous RNA using genetically encoded probes.

    PubMed

    Ozawa, Takeaki; Umezawa, Yoshio

    2011-03-01

    Imaging of RNAs in single cells revealed their localized transcription and specific function. Such information cannot be obtained from bulk measurements. This unit contains a protocol of an imaging method capable of visualizing endogenous RNAs bound to genetically encoded fluorescent probes in single living cells. The protocol includes methods of design and construction of the probes, their characterization, and imaging a target RNA in living cells. The methods for RNA imaging are generally applicable to many kinds of RNAs and may allow for elucidating novel functions of localized RNAs and understanding their dynamics in living cells. Curr. Protoc. Chem. Biol. 3:27-37 © 2011 by John Wiley & Sons, Inc.

  9. Fluorogenic Probes for Multicolor Imaging in Living Cells.

    PubMed

    Lukinavičius, Gražvydas; Reymond, Luc; Umezawa, Keitaro; Sallin, Olivier; D'Este, Elisa; Göttfert, Fabian; Ta, Haisen; Hell, Stefan W; Urano, Yasuteru; Johnsson, Kai

    2016-08-01

    Here we present a far-red, silicon-rhodamine-based fluorophore (SiR700) for live-cell multicolor imaging. SiR700 has excitation and emission maxima at 690 and 715 nm, respectively. SiR700-based probes for F-actin, microtubules, lysosomes, and SNAP-tag are fluorogenic, cell-permeable, and compatible with superresolution microscopy. In conjunction with probes based on the previously introduced carboxy-SiR650, SiR700-based probes permit multicolor live-cell superresolution microscopy in the far-red, thus significantly expanding our capacity for imaging living cells. PMID:27420907

  10. Near-infrared Molecular Probes for In Vivo Imaging

    PubMed Central

    Zhang, Xuan; Bloch, Sharon; Akers, Walter; Achilefu, Samuel

    2012-01-01

    Cellular and tissue imaging in the near-infrared (NIR) wavelengths between 700 and 900 nm is advantageous for in vivo because of the low absorption of biological molecules in this region. This Unit presents protocols for small animal imaging using planar and fluorescence lifetime imaging techniques. Included is an overview of NIR fluorescence imaging of cells and small animals using NIR organic fluorophores, nanoparticles, and multimodal imaging probes. The development, advantages, and application of NIR fluorescent probes that have been used for in vivo imaging are also summarized. The use of NIR agents in conjunction with visible dyes and considerations in selecting imaging agents are discussed. We conclude with practical considerations for the use of these dyes in cell and small animal imaging applications. PMID:22470154

  11. Imaging theory of structured pump-probe microscopy.

    PubMed

    Massaro, Eric S; Hill, Andrew H; Kennedy, Casey L; Grumstrup, Erik M

    2016-09-01

    With sub-micron spatial resolution and femtosecond temporal resolution, pump probe microscopy provides a powerful spectroscopic probe of complex electronic environments in bulk and nanoscale materials. However, the electronic structure of many materials systems are governed by compositional and morphological heterogeneities on length scales that lie below the diffraction limit. We have recently demonstrated Structured Pump Probe Microscopy (SPPM), which employs a patterned pump excitation field to provide spectroscopic interrogation of sub-diffraction limited sample volumes. Herein, we develop the imaging theory of SPPM in two dimensions to accompany the previously published experimental methodology. We show that regardless of pump and probe wavelengths, a nearly two-fold reduction in spectroscopic probe volume can be achieved. We also examine the limitations of the approach, with a detailed discussion of ringing in the point spread function that can reduce imaging performance. PMID:27607691

  12. Spatial-scanning hyperspectral imaging probe for bio-imaging applications

    NASA Astrophysics Data System (ADS)

    Lim, Hoong-Ta; Murukeshan, Vadakke Matham

    2016-03-01

    The three common methods to perform hyperspectral imaging are the spatial-scanning, spectral-scanning, and snapshot methods. However, only the spectral-scanning and snapshot methods have been configured to a hyperspectral imaging probe as of today. This paper presents a spatial-scanning (pushbroom) hyperspectral imaging probe, which is realized by integrating a pushbroom hyperspectral imager with an imaging probe. The proposed hyperspectral imaging probe can also function as an endoscopic probe by integrating a custom fabricated image fiber bundle unit. The imaging probe is configured by incorporating a gradient-index lens at the end face of an image fiber bundle that consists of about 50 000 individual fiberlets. The necessary simulations, methodology, and detailed instrumentation aspects that are carried out are explained followed by assessing the developed probe's performance. Resolution test targets such as United States Air Force chart as well as bio-samples such as chicken breast tissue with blood clot are used as test samples for resolution analysis and for performance validation. This system is built on a pushbroom hyperspectral imaging system with a video camera and has the advantage of acquiring information from a large number of spectral bands with selectable region of interest. The advantages of this spatial-scanning hyperspectral imaging probe can be extended to test samples or tissues residing in regions that are difficult to access with potential diagnostic bio-imaging applications.

  13. Optically Detected Scanned Probe Magnetic Resonance Imaging

    NASA Astrophysics Data System (ADS)

    Wolfe, Christopher; Bhallamudi, Vidya; Wang, Hailong; Du, Chunhui; Manuilov, Sergei; Adur, Rohan; Yang, Fengyuan; Hammel, P. Chris

    2014-03-01

    Magnetic resonance is a powerful tool for studying magnetic properties and dynamics of spin systems. Scanned magnetic probes can induce spatially localized resonance due to the strong magnetic field and gradient near the magnetic tip., Nitrogen vacancy centers (NV) in diamond provide a sensitive means of measuring magnetic fields at the nanoscale. We report preliminary results towards using the high sensitivity of NV detection with a scanned magnetic probe to study local magnetic phenomena. This work is supported by the Center for Emergent Materials at The Ohio State University, a NSF Materials Research Science and Engineering Center (DMR-0820414).

  14. In vivo characterization of activatable cell penetrating peptides for targeting protease activity in cancer

    PubMed Central

    Olson, Emilia S.; Aguilera, Todd A.; Jiang, Tao; Ellies, Lesley G.; Nguyen, Quyen T.; Wong, Edmund; Gross, Larry; Tsien, Roger Y.

    2009-01-01

    Activatable cell penetrating peptides (ACPPs) are novel in vivo targeting agents comprised of a polycationic cell penetrating peptide (CPP) connected via a cleavable linker to a neutralizing polyanion (Fig. 1A). Adsorption and uptake into cells are inhibited until the linker is proteolyzed1–3. An ACPP cleavable by matrix metalloproteinase-2 (MMP-2) in vitro was the first one demonstrated to work in a tumor model in vivo, but only HT-1080 xenografts and resected human squamous cell carcinomas were tested. Generality to other cancer types, in vivo selectivity of ACPPs for MMPs, and spatial resolution require further characterization. We now show that ACPPs can target many xenograft tumor models from different cancer sites, as well as a well thoroughly studied transgenic model of spontaneous breast cancer (mouse mammary tumor virus promoter driving polyoma middle T antigen, MMTV-PyMT). Pharmacological inhibitors and genetic knockouts indicate that current ACPPs are selective for MMP-2 and MMP-9 in the above in vivo models. In accord with the known local distribution of MMP activity, accumulation is strongest at the tumor-stromal interface in primary tumors and associated metastases, indicating better spatial resolution (<50 µm) than other currently available MMP-cleavable probes4. We also find that background uptake of ACPPs into normal tissues such as liver and kidney can be decreased by appending inert macromolecules of 30–50 KDa to the polyanionic inhibitory domain. Our results validate an approach that should generally deliver imaging agents and chemotherapeutics to sites of invasion, tumor-promoting inflammation, and metastasis. PMID:20023745

  15. Intracellular probes for imaging oxygen concentration: how good are they?

    NASA Astrophysics Data System (ADS)

    Dmitriev, Ruslan I.; Papkovsky, Dmitri B.

    2015-09-01

    In the last decade a number of cell-permeable phosphorescence based probes for imaging of (intra)cellular oxygen (icO2) have been described. These small molecule, supramolecular and nanoparticle structures, although allowing analysis of hypoxia, local gradients and fluctuations in O2, responses to stimulation and drug treatment at sub-cellular level with high spatial and temporal resolution, differ significantly in their operational performance and applicability to different cell and tissue models. Here we discuss and compare these probes with respect to their staining efficiency, brightness, photostability, toxicity, cell specificity, compatibility with different cell and tissue models, and analytical performance. Merits and limitations of particular probes are highlighted and strategies for development of new high-performance O2 imaging probes defined. Key application areas in hypoxia research, stem cells, cancer biology and tissue physiology are also discussed.

  16. Extremely sharp carbon nanocone probes for atomic force microscopy imaging

    NASA Astrophysics Data System (ADS)

    Chen, I.-Chen; Chen, Li-Han; Ye, Xiang-Rong; Daraio, Chiara; Jin, Sungho; Orme, Christine A.; Quist, Arjan; Lal, Ratnesh

    2006-04-01

    A simple and reliable catalyst patterning technique combined with electric-field-guided growth is utilized to synthesize a sharp and high-aspect-ratio carbon nanocone probe on a tipless cantilever for atomic force microscopy. A single carbon nanodot produced by an electron-beam-induced deposition serves as a convenient chemical etch mask for catalyst patterning, thus eliminating the need for complicated, resist-based, electron-beam lithography for a nanoprobe fabrication. A gradual, sputtering-induced size reduction and eventual removal of the catalyst particle at the probe tip during electric-field-guided growth creates a sharp probe with a tip radius of only a few nanometers. These fabrication processes are amenable for the wafer-scale synthesis of multiple probes. High resolution imaging of three-dimensional features and deep trenches, and mechanical durability enabling continuous operation for many hours without noticeable image deterioration have been demonstrated.

  17. Monte Carlo modeling of ultrasound probes for image guided radiotherapy

    SciTech Connect

    Bazalova-Carter, Magdalena; Schlosser, Jeffrey; Chen, Josephine; Hristov, Dimitre

    2015-10-15

    Purpose: To build Monte Carlo (MC) models of two ultrasound (US) probes and to quantify the effect of beam attenuation due to the US probes for radiation therapy delivered under real-time US image guidance. Methods: MC models of two Philips US probes, an X6-1 matrix-array transducer and a C5-2 curved-array transducer, were built based on their megavoltage (MV) CT images acquired in a Tomotherapy machine with a 3.5 MV beam in the EGSnrc, BEAMnrc, and DOSXYZnrc codes. Mass densities in the probes were assigned based on an electron density calibration phantom consisting of cylinders with mass densities between 0.2 and 8.0 g/cm{sup 3}. Beam attenuation due to the US probes in horizontal (for both probes) and vertical (for the X6-1 probe) orientation was measured in a solid water phantom for 6 and 15 MV (15 × 15) cm{sup 2} beams with a 2D ionization chamber array and radiographic films at 5 cm depth. The MC models of the US probes were validated by comparison of the measured dose distributions and dose distributions predicted by MC. Attenuation of depth dose in the (15 × 15) cm{sup 2} beams and small circular beams due to the presence of the probes was assessed by means of MC simulations. Results: The 3.5 MV CT number to mass density calibration curve was found to be linear with R{sup 2} > 0.99. The maximum mass densities in the X6-1 and C5-2 probes were found to be 4.8 and 5.2 g/cm{sup 3}, respectively. Dose profile differences between MC simulations and measurements of less than 3% for US probes in horizontal orientation were found, with the exception of the penumbra region. The largest 6% dose difference was observed in dose profiles of the X6-1 probe placed in vertical orientation, which was attributed to inadequate modeling of the probe cable. Gamma analysis of the simulated and measured doses showed that over 96% of measurement points passed the 3%/3 mm criteria for both probes placed in horizontal orientation and for the X6-1 probe in vertical orientation. The

  18. Monte Carlo modeling of ultrasound probes for image guided radiotherapy

    PubMed Central

    Bazalova-Carter, Magdalena; Schlosser, Jeffrey; Chen, Josephine; Hristov, Dimitre

    2015-01-01

    Purpose: To build Monte Carlo (MC) models of two ultrasound (US) probes and to quantify the effect of beam attenuation due to the US probes for radiation therapy delivered under real-time US image guidance. Methods: MC models of two Philips US probes, an X6-1 matrix-array transducer and a C5-2 curved-array transducer, were built based on their megavoltage (MV) CT images acquired in a Tomotherapy machine with a 3.5 MV beam in the EGSnrc, BEAMnrc, and DOSXYZnrc codes. Mass densities in the probes were assigned based on an electron density calibration phantom consisting of cylinders with mass densities between 0.2 and 8.0 g/cm3. Beam attenuation due to the US probes in horizontal (for both probes) and vertical (for the X6-1 probe) orientation was measured in a solid water phantom for 6 and 15 MV (15 × 15) cm2 beams with a 2D ionization chamber array and radiographic films at 5 cm depth. The MC models of the US probes were validated by comparison of the measured dose distributions and dose distributions predicted by MC. Attenuation of depth dose in the (15 × 15) cm2 beams and small circular beams due to the presence of the probes was assessed by means of MC simulations. Results: The 3.5 MV CT number to mass density calibration curve was found to be linear with R2 > 0.99. The maximum mass densities in the X6-1 and C5-2 probes were found to be 4.8 and 5.2 g/cm3, respectively. Dose profile differences between MC simulations and measurements of less than 3% for US probes in horizontal orientation were found, with the exception of the penumbra region. The largest 6% dose difference was observed in dose profiles of the X6-1 probe placed in vertical orientation, which was attributed to inadequate modeling of the probe cable. Gamma analysis of the simulated and measured doses showed that over 96% of measurement points passed the 3%/3 mm criteria for both probes placed in horizontal orientation and for the X6-1 probe in vertical orientation. The X6-1 probe in vertical

  19. Quantitative imaging of disease signatures through radioactive decay signal conversion

    PubMed Central

    Thorek, Daniel LJ; Ogirala, Anuja; Beattie, Bradley J; Grimm, Jan

    2013-01-01

    In the era of personalized medicine there is an urgent need for in vivo techniques able to sensitively detect and quantify molecular activities. Sensitive imaging of gamma rays is widely used, but radioactive decay is a physical constant and signal is independent of biological interactions. Here we introduce a framework of novel targeted and activatable probes excited by a nuclear decay-derived signal to identify and measure molecular signatures of disease. This was accomplished utilizing Cerenkov luminescence (CL), the light produced by β-emitting radionuclides such as clinical positron emission tomography (PET) tracers. Disease markers were detected using nanoparticles to produce secondary Cerenkov-induced fluorescence. This approach reduces background signal compared to conventional fluorescence imaging. In addition to information from a PET scan, we demonstrate novel medical utility by quantitatively determining prognostically relevant enzymatic activity. This technique can be applied to monitor other markers and facilitates a shift towards activatable nuclear medicine agents. PMID:24013701

  20. SPRITE: a modern approach to scanning probe contact resonance imaging

    NASA Astrophysics Data System (ADS)

    Kos, A. B.; Killgore, J. P.; Hurley, D. C.

    2014-02-01

    We describe a system for contact resonance tracking called scanning probe resonance image tracking electronics (SPRITE). SPRITE can image two contact resonance frequencies simultaneously and thus can be used to acquire quantitative mechanical properties without requiring tedious image registration or other forms of post-processing. SPRITE is up to ten times faster than its predecessor, and its use of digital frequency synthesis makes the frequency 100 times more precise. In addition, SPRITE can acquire quality factor images, which can be used to determine viscoelastic material properties. The resonant frequency of two eigenmodes and two corresponding quality factor images can be acquired simultaneously. These new features can enable accurate nanomechanical imaging of surfaces and devices.

  1. Using image processing techniques on proximity probe signals in rotordynamics

    NASA Astrophysics Data System (ADS)

    Diamond, Dawie; Heyns, Stephan; Oberholster, Abrie

    2016-06-01

    This paper proposes a new approach to process proximity probe signals in rotordynamic applications. It is argued that the signal be interpreted as a one dimensional image. Existing image processing techniques can then be used to gain information about the object being measured. Some results from one application is presented. Rotor blade tip deflections can be calculated through localizing phase information in this one dimensional image. It is experimentally shown that the newly proposed method performs more accurately than standard techniques, especially where the sampling rate of the data acquisition system is inadequate by conventional standards.

  2. Fluorescence lifetime imaging by asynchronous pump-probe microscopy.

    PubMed Central

    Dong, C Y; So, P T; French, T; Gratton, E

    1995-01-01

    We report the development of a scanning lifetime fluorescence microscope using the asynchronous, pump-probe (stimulated emission) approach. There are two significant advantages of this technique. First, the cross-correlation signal produced by overlapping the pump and probe lasers results in i) an axial sectioning effect similar to that in confocal and two-photon excitation microscopy, and ii) improved spatial resolution compared to conventional one-photon fluorescence microscopy. Second, the low-frequency, cross-correlation signal generated allows lifetime-resolved imaging without using fast photodetectors. The data presented here include 1) determination of laser sources' threshold powers for linearity in the pump-probe signal; 2) characterization of the pump-probe intensity profile using 0.28 microns fluorescent latex spheres; 3) high frequency (up to 6.7 GHz) lifetime measurement of rhodamine B in water; and 4) lifetime-resolved images of fluorescent latex spheres, human erythrocytes and a mouse fibroblast cell stained by rhodamine DHPE, and a mouse fibroblast labeled with ethidium bromide and rhodamine DHPE. Images FIGURE 2 FIGURE 6 FIGURE 7 FIGURE 8 PMID:8599631

  3. Activity-based imaging probes of the proteasome.

    PubMed

    Carmony, Kimberly Cornish; Kim, Kyung Bo

    2013-09-01

    Over the years, the proteasome has been extensively investigated due to its crucial roles in many important signaling pathways and its implications in diseases. Two proteasome inhibitors--bortezomib and carfilzomib--have received FDA approval for the treatment of multiple myeloma, thereby validating the proteasome as a chemotherapeutic target. As a result, further research efforts have been focused on dissecting the complex biology of the proteasome to gain the insight required for developing next-generation proteasome inhibitors. It is clear that chemical probes have made significant contributions to these efforts, mostly by functioning as inhibitors that selectively block the catalytic activity of proteasomes. Analogues of these inhibitors are now providing additional tools for visualization of catalytically active proteasome subunits, several of which allow real-time monitoring of proteasome activity in living cells as well as in in vivo settings. These imaging probes will provide powerful tools for assessing the efficacy of proteasome inhibitors in clinical settings. In this review, we will focus on the recent efforts towards developing imaging probes of proteasomes, including the latest developments in immunoproteasome-selective imaging probes. PMID:23700161

  4. Doped semiconductor nanocrystal based fluorescent cellular imaging probes

    NASA Astrophysics Data System (ADS)

    Maity, Amit Ranjan; Palmal, Sharbari; Basiruddin, Sk; Karan, Niladri Sekhar; Sarkar, Suresh; Pradhan, Narayan; Jana, Nikhil R.

    2013-05-01

    Doped semiconductor nanocrystals such as Mn doped ZnS, Mn doped ZnSe and Cu doped InZnS, are considered as new classes of fluorescent biological probes with low toxicity. Although the synthesis in high quality of such nanomaterials is now well established, transforming them into functional fluorescent probes remains a challenge. Here we report a fluorescent cellular imaging probe made of high quality doped semiconductor nanocrystals. We have identified two different coating approaches suitable for transforming the as synthesized hydrophobic doped semiconductor nanocrystals into water-soluble functional nanoparticles. Following these approaches we have synthesized TAT-peptide- and folate-functionalized nanoparticles of 10-80 nm hydrodynamic diameter and used them as a fluorescent cell label. The results shows that doped semiconductor nanocrystals can be an attractive alternative for conventional cadmium based quantum dots with low toxicity.Doped semiconductor nanocrystals such as Mn doped ZnS, Mn doped ZnSe and Cu doped InZnS, are considered as new classes of fluorescent biological probes with low toxicity. Although the synthesis in high quality of such nanomaterials is now well established, transforming them into functional fluorescent probes remains a challenge. Here we report a fluorescent cellular imaging probe made of high quality doped semiconductor nanocrystals. We have identified two different coating approaches suitable for transforming the as synthesized hydrophobic doped semiconductor nanocrystals into water-soluble functional nanoparticles. Following these approaches we have synthesized TAT-peptide- and folate-functionalized nanoparticles of 10-80 nm hydrodynamic diameter and used them as a fluorescent cell label. The results shows that doped semiconductor nanocrystals can be an attractive alternative for conventional cadmium based quantum dots with low toxicity. Electronic supplementary information available: Characterization details of coating and

  5. Integrated ultrasound and gamma imaging probe for medical diagnosis

    NASA Astrophysics Data System (ADS)

    Pani, R.; Pellegrini, R.; Cinti, M. N.; Polito, C.; Orlandi, C.; Fabbri, A.; De Vincentis, G.

    2016-03-01

    In the last few years, integrated multi-modality systems have been developed, aimed at improving the accuracy of medical diagnosis correlating information from different imaging techniques. In this contest, a novel dual modality probe is proposed, based on an ultrasound detector integrated with a small field of view single photon emission gamma camera. The probe, dedicated to visualize small organs or tissues located at short depths, performs dual modality images and permits to correlate morphological and functional information. The small field of view gamma camera consists of a continuous NaI:Tl scintillation crystal coupled with two multi-anode photomultiplier tubes. Both detectors were characterized in terms of position linearity and spatial resolution performances in order to guarantee the spatial correspondence between the ultrasound and the gamma images. Finally, dual-modality images of custom phantoms are obtained highlighting the good co-registration between ultrasound and gamma images, in terms of geometry and image processing, as a consequence of calibration procedures.

  6. Molecular Imaging Probes for Positron Emission Tomography and Optical Imaging of Sentinel Lymph Node and Tumor

    NASA Astrophysics Data System (ADS)

    Qin, Zhengtao

    Molecular imaging is visualizations and measurements of in vivo biological processes at the molecular or cellular level using specific imaging probes. As an emerging technology, biocompatible macromolecular or nanoparticle based targeted imaging probes have gained increasing popularities. Those complexes consist of a carrier, an imaging reporter, and a targeting ligand. The active targeting ability dramatically increases the specificity. And the multivalency effect may further reduce the dose while providing a decent signal. In this thesis, sentinel lymph node (SLN) mapping and cancer imaging are two research topics. The focus is to develop molecular imaging probes with high specificity and sensitivity, for Positron Emission Tomography (PET) and optical imaging. The objective of this thesis is to explore dextran radiopharmaceuticals and porous silicon nanoparticles based molecular imaging agents. Dextran polymers are excellent carriers to deliver imaging reporters or therapeutic agents due to its well established safety profile and oligosaccharide conjugation chemistry. There is also a wide selection of dextran polymers with different lengths. On the other hand, Silicon nanoparticles represent another class of biodegradable materials for imaging and drug delivery. The success in fluorescence lifetime imaging and enhancements of the immune activation potency was briefly discussed. Chapter 1 begins with an overview on current molecular imaging techniques and imaging probes. Chapter 2 presents a near-IR dye conjugated probe, IRDye 800CW-tilmanocept. Fluorophore density was optimized to generate the maximum brightness. It was labeled with 68Ga and 99mTc and in vivo SLN mapping was successfully performed in different animals, such as mice, rabbits, dogs and pigs. With 99mTc labeled IRDye 800CW-tilmanocept, chapter 3 introduces a two-day imaging protocol with a hand-held imager. Chapter 4 proposed a method to dual radiolabel the IRDye 800CW-tilmanocept with both 68Ga and

  7. Characterization of a Fluorescent Probe for Imaging Nitric Oxide

    PubMed Central

    Ghebremariam, Yohannes T; Huang, Ngan F; Kambhampati, Swetha; Volz, Katharina S; Joshi, Gururaj G; Anslyn, Eric V; Cooke, John P

    2014-01-01

    Background Nitric Oxide (NO), a potent vasodilator and anti-atherogenic molecule, is synthesized in various cell types including vascular endothelial cells (ECs). The biological importance of NO enforces the need to develop and characterize specific and sensitive probes. To date, several fluorophores, chromophores and colorimetric techniques have been developed to detect NO or its metabolites (NO2 and NO3) in biological fluids, viable cells or cell lysates. Methods Recently, a novel probe (NO550) has been developed and reported to detect NO in solution and in primary astrocytes and neuronal cells with a fluorescence signal arising from a non-fluorescent background. Results Here, we report further characterization of this probe by optimizing conditions for the detection and imaging of NO products in primary vascular endothelial cells, fibroblasts, embryonic stem cell (ESC)- and induced pluripotent stem cell (iPSC)- derived endothelial cells (ESC-ECs. and iPSC-ECs respectively) in the absence and presence of pharmacological agents that modulate NO levels. In addition, we studied the stability of this probe in cells over time and evaluated its compartmentalization in reference to organelle-labeling dyes. Finally, we synthesized an inherently fluorescent diazo ring compound (AZO550) that is expected to form when the non-fluorescent NO550 reacts with cellular NO and compared its cellular distribution with that of NO550. Conclusion NO550 is a promising agent for imaging NO at baseline and in response to pharmacological agents that modulate its levels. PMID:24335468

  8. Probes for multidimensional nanospectroscopic imaging and methods of fabrication thereof

    DOEpatents

    Weber-Bargioni, Alexander; Cabrini, Stefano; Bao, Wei; Melli, Mauro; Yablonovitch, Eli; Schuck, Peter J

    2015-03-17

    This disclosure provides systems, methods, and apparatus related to probes for multidimensional nanospectroscopic imaging. In one aspect, a method includes providing a transparent tip comprising a dielectric material. A four-sided pyramidal-shaped structure is formed at an apex of the transparent tip using a focused ion beam. Metal layers are deposited over two opposing sides of the four-sided pyramidal-shaped structure.

  9. Engineering imaging probes and molecular machines for nanomedicine.

    PubMed

    Tong, Sheng; Cradick, Thomas J; Ma, Yan; Dai, Zhifei; Bao, Gang

    2012-10-01

    Nanomedicine is an emerging field that integrates nanotechnology, biomolecular engineering, life sciences and medicine; it is expected to produce major breakthroughs in medical diagnostics and therapeutics. Due to the size-compatibility of nano-scale structures and devices with proteins and nucleic acids, the design, synthesis and application of nanoprobes, nanocarriers and nanomachines provide unprecedented opportunities for achieving a better control of biological processes, and drastic improvements in disease detection, therapy, and prevention. Recent advances in nanomedicine include the development of functional nanoparticle based molecular imaging probes, nano-structured materials as drug/gene carriers for in vivo delivery, and engineered molecular machines for treating single-gene disorders. This review focuses on the development of molecular imaging probes and engineered nucleases for nanomedicine, including quantum dot bioconjugates, quantum dot-fluorescent protein FRET probes, molecular beacons, magnetic and gold nanoparticle based imaging contrast agents, and the design and validation of zinc finger nucleases (ZFNs) and TAL effector nucleases (TALENs) for gene targeting. The challenges in translating nanomedicine approaches to clinical applications are discussed.

  10. Photoacoustic imaging of fluorophores using pump-probe excitation

    PubMed Central

    Märk, Julia; Schmitt, Franz-Josef; Theiss, Christoph; Dortay, Hakan; Friedrich, Thomas; Laufer, Jan

    2015-01-01

    A pump-probe technique for the detection of fluorophores in tomographic PA images is introduced. It is based on inducing stimulated emission in fluorescent molecules, which in turn modulates the amount of thermalized energy, and hence the PA signal amplitude. A theoretical model of the PA signal generation in fluorophores is presented and experimentally validated on cuvette measurements made in solutions of Rhodamine 6G, a fluorophore of known optical and molecular properties. The application of this technique to deep tissue tomographic PA imaging is demonstrated by determining the spatial distribution of a near-infrared fluorophore in a tissue phantom. PMID:26203378

  11. Integrated transrectal probe for translational ultrasound-photoacoustic imaging

    NASA Astrophysics Data System (ADS)

    Bell, Kevan L.; Harrison, Tyler; Usmani, Nawaid; Zemp, Roger J.

    2016-03-01

    A compact photoacoustic transrectal probe is constructed for improved imaging in brachytherapy treatment. A 192 element 5 MHz linear transducer array is mounted inside a small 3D printed casing along with an array of optical fibers. The device is fed by a pump laser and tunable NIR-optical parametric oscillator with data collected by a Verasonics ultrasound platform. This assembly demonstrates improved imaging of brachytherapy seeds in phantoms with depths up to 5 cm. The tuneable excitation in combination with standard US integration provides adjustable contrast between the brachytherapy seeds, blood filled tubes and background tissue.

  12. Thrombin activatable fibrinolysis inhibitor as a bleeding predictor in liver transplantation: a pilot observational study

    PubMed Central

    Nedel, Wagner Luis; Rodrigues Filho, Edison Moraes; Pasqualotto, Alessandro Comarú

    2016-01-01

    Objective To correlate the levels of thrombin activatable fibrinolysis inhibitor in the immediate postoperative period and at 24 hours postoperatively with the volume of intraoperative bleeding. Methods Twenty-one patients allocated immediately before (elective or emergency) liver transplantation were analyzed. Blood samples were collected for thrombin activatable fibrinolysis inhibitor analysis at three different time points: immediately before liver transplantation (preoperative thrombin activatable fibrinolysis inhibitor), immediately after the surgical procedure (immediate postoperative thrombin activatable fibrinolysis inhibitor), and 24 hours after surgery (thrombin activatable fibrinolysis inhibitor 24 hours after surgery). The primary outcome of the study was to correlate the preoperative and immediate postoperative levels of thrombin activatable fibrinolysis inhibitor with intraoperative blood loss. Results There was a correlation between the preoperative thrombin activatable fibrinolysis inhibitor levels and bleeding volume (ρ = -0.469; p = 0.05) but no correlation between the immediate postoperative thrombin activatable fibrinolysis inhibitor and bleeding volume (ρ = -0.062; p = 0.79). No variable included in the linear regression analysis (prehemoglobin, prefibrinogen and preoperative thrombin activatable fibrinolysis inhibitor) was a bleeding predictor. There was a similar trend in the variation between the levels of thrombin activatable fibrinolysis inhibitor at the three different time points and fibrinogen levels. Patients who died within 6 months (14.3%) showed decreased preoperative and immediate postoperative levels of thrombin activatable fibrinolysis compared with survivors (preoperative: 1.3 ± 0.15 versus 2.55 ± 0.53, p = 0.06; immediate postoperative: 1.2 ± 0.15 versus 2.5 ± 0.42, p = 0.007). Conclusion There was a moderate correlation between preoperative thrombin activatable fibrinolysis inhibitor and intraoperative bleeding in liver

  13. Chemical synthesis of a two-photon-activatable chemokine and photon-guided lymphocyte migration in vivo

    PubMed Central

    Chen, Xin; Tang, Shan; Zheng, Ji-Shen; Zhao, Ruozhu; Wang, Zhi-Peng; Shao, Wen; Chang, Hao-Nan; Cheng, Jing-Yuan; Zhao, Hui; Liu, Lei; Qi, Hai

    2015-01-01

    Chemokine-guided lymphocyte positioning in tissues is crucial for normal operation of the immune system. Direct, real-time manipulation and measurement of single-cell responses to chemokines is highly desired for investigating the cell biology of lymphocyte migration in vivo. Here we report the development of the first two-photon-activatable chemokine CCL5 through efficient one-pot total chemical synthesis in milligram scale. By spatiotemporally controlled photoactivation, we show at the single-cell level that T cells perceive the directional cue without relying on PI3K activities, which are nonetheless required for persistent migration over an extended period of time. By intravital imaging, we demonstrate artificial T-cell positioning in cutaneous tissues and lymph nodes. This work establishes a general strategy to develop high-quality photo-activatable protein agents through tailor-designed caging of multiple residues and highlights the potential of photo-activatable chemokines for understanding and potential therapeutic manipulation of cell positioning and position-controlled cell behaviours in vivo. PMID:26008852

  14. Feasibility of Amylin Imaging in Pancreatic Islets with β-Amyloid Imaging Probes

    PubMed Central

    Yoshimura, Masashi; Ono, Masahiro; Watanabe, Hiroyuki; Kimura, Hiroyuki; Saji, Hideo

    2014-01-01

    Islet amyloid deposition composed of amylin aggregates is regarded as one of the hallmarks of type 2 diabetes mellitus (T2DM). For the diagnosis of T2DM, several nuclear medical imaging probes have been developed. However, there have been no reports regarding the development of imaging probes targeting amylin. In this report, we investigated the feasibility of amylin imaging using [125I]IPBF as one of the model compounds of β-amyloid (Aβ) imaging probes. In in vitro experiments, [125I]IPBF exhibited high binding affinity for amylin aggregates (Kd = 8.31 nM). Moreover, autoradiographic images showed that [125I]IPBF specifically bound to islet amyloid composed of amylin. These results suggest the potential application of Aβ imaging probes to amylin imaging. In addition, [125I]IPBF is one of the promising lead compounds for amylin imaging, and further structural optimization based on [125I]IPBF may lead to useful tracers for the in vivo imaging of islet amyloids in the pancreas. PMID:25142178

  15. Molecular Probes for Imaging Myelinated White Matter in CNS

    PubMed Central

    Wu, Chunying; Wei, Jinjun; Tian, Donghua; Feng, Yue; Miller, Robert H.; Wang, Yanming

    2009-01-01

    Abnormalities and changes in myelination in the brain are seen in many neurodegenerative disorders such as multiple sclerosis (MS). Direct detection and quantification of myelin content in vivo is desired to facilitate diagnosis and therapeutic treatments of myelin-related diseases. The imaging studies require use of myelin-imaging agents that readily enter the brain and selectively bind to myelinated regions. For this purpose, we have systematically evaluated a series of stilbene derivatives as myelin imaging agents. Spectrophotometry-based and radioligand-based binding assays showed that these stilbene derivatives exhibited relatively high myelin-binding affinities. In vitro myelin staining exhibited that the compounds selectively stained intact myelinated regions in wild type mouse brain. In situ tissue staining demonstrated that the compounds readily entered the mouse brain and selectively labeled myelinated white matter regions. These studies suggested that these stilbene derivatives can be used as myelin-imaging probes to monitor myelin pathology in vivo. PMID:18844339

  16. In vivo imaging of light-emitting probes

    NASA Astrophysics Data System (ADS)

    Rice, Bradley W.; Cable, Michael D.; Nelson, Michael B.

    2001-10-01

    In vivo imaging of cells tagged with light-emitting probes, such as firefly luciferase or fluorescent proteins, is a powerful technology that enables a wide range of biological studies in small research animals. Reporters with emission in the red to infrared (> 600 nm) are preferred due to the low absorption in tissue at these wavelengths. Modeling of photon diffusion through tissue indicates that bioluminescent cell counts as low as a few hundred can be detected subcutaneously, while approximately106 cells are required to detect signals at approximately 2 cm depth in tissue. Signal-to- noise estimates show that cooled back-thinned integrating charge coupled devices (CCDs) are preferred to image-intensified CCDs for this application, mainly due to their high quantum efficiency (approximately 85%) at wavelengths > 600 nm where tissue absorption is low. Instrumentation for in vivo imaging developed at Xenogen is described and several examples of images of mice with bioluminescent cells are presented.

  17. Real-time chemiluminescence imaging using nano-lantern probes.

    PubMed

    Arai, Yoshiyuki; Nagai, Takeharu

    2014-12-01

    Chemiluminescence imaging can be performed without excitation light sources at various spatial levels ranging from a single cell to the whole body. Thus far, chemiluminescence imaging has been primarily performed with long exposure times because of weak signals, resulting in low temporal resolution. Recently, the brightest-known chemiluminescent proteins--Nano-lantern and Nano-lantern-based functional indicators--have been developed. Nano-lantern probes break the limitation of temporal resolution and enable chemiluminescence imaging of living samples such as cells, plants, and small animals at video rates. This unit describes one protocol for observation of a freely moving unshaved mouse transplanted with Nano-lantern-expressing tumor cells, and another for compatible use of optogenetic tools and a Nano-lantern calcium indicator. Both protocols utilize the synchronization of illumination and camera acquisition sessions, thereby enabling real-time chemiluminescence imaging.

  18. Functional Scanning Probe Imaging of Nanostructured Solar Energy Materials.

    PubMed

    Giridharagopal, Rajiv; Cox, Phillip A; Ginger, David S

    2016-09-20

    From hybrid perovskites to semiconducting polymer/fullerene blends for organic photovoltaics, many new materials being explored for energy harvesting and storage exhibit performance characteristics that depend sensitively on their nanoscale morphology. At the same time, rapid advances in the capability and accessibility of scanning probe microscopy methods over the past decade have made it possible to study processing/structure/function relationships ranging from photocurrent collection to photocarrier lifetimes with resolutions on the scale of tens of nanometers or better. Importantly, such scanning probe methods offer the potential to combine measurements of local structure with local function, and they can be implemented to study materials in situ or devices in operando to better understand how materials evolve in time in response to an external stimulus or environmental perturbation. This Account highlights recent advances in the development and application of scanning probe microscopy methods that can help address such questions while filling key gaps between the capabilities of conventional electron microscopy and newer super-resolution optical methods. Focusing on semiconductor materials for solar energy applications, we highlight a range of electrical and optoelectronic scanning probe microscopy methods that exploit the local dynamics of an atomic force microscope tip to probe key properties of the solar cell material or device structure. We discuss how it is possible to extract relevant device properties using noncontact scanning probe methods as well as how these properties guide materials development. Specifically, we discuss intensity-modulated scanning Kelvin probe microscopy (IM-SKPM), time-resolved electrostatic force microscopy (trEFM), frequency-modulated electrostatic force microscopy (FM-EFM), and cantilever ringdown imaging. We explain these developments in the context of classic atomic force microscopy (AFM) methods that exploit the physics of

  19. Functional Scanning Probe Imaging of Nanostructured Solar Energy Materials.

    PubMed

    Giridharagopal, Rajiv; Cox, Phillip A; Ginger, David S

    2016-09-20

    From hybrid perovskites to semiconducting polymer/fullerene blends for organic photovoltaics, many new materials being explored for energy harvesting and storage exhibit performance characteristics that depend sensitively on their nanoscale morphology. At the same time, rapid advances in the capability and accessibility of scanning probe microscopy methods over the past decade have made it possible to study processing/structure/function relationships ranging from photocurrent collection to photocarrier lifetimes with resolutions on the scale of tens of nanometers or better. Importantly, such scanning probe methods offer the potential to combine measurements of local structure with local function, and they can be implemented to study materials in situ or devices in operando to better understand how materials evolve in time in response to an external stimulus or environmental perturbation. This Account highlights recent advances in the development and application of scanning probe microscopy methods that can help address such questions while filling key gaps between the capabilities of conventional electron microscopy and newer super-resolution optical methods. Focusing on semiconductor materials for solar energy applications, we highlight a range of electrical and optoelectronic scanning probe microscopy methods that exploit the local dynamics of an atomic force microscope tip to probe key properties of the solar cell material or device structure. We discuss how it is possible to extract relevant device properties using noncontact scanning probe methods as well as how these properties guide materials development. Specifically, we discuss intensity-modulated scanning Kelvin probe microscopy (IM-SKPM), time-resolved electrostatic force microscopy (trEFM), frequency-modulated electrostatic force microscopy (FM-EFM), and cantilever ringdown imaging. We explain these developments in the context of classic atomic force microscopy (AFM) methods that exploit the physics of

  20. Magnetic field mapping using an image-intensifying fluorescent probe

    NASA Astrophysics Data System (ADS)

    Tou, T. Y.; Blackwell, B. D.; Sharp, L. E.

    1991-05-01

    A simple, cost-effective image-intensifying fluorescent probe designed for mapping the magnetic surfaces in the heliac sheila is described. It consists of a phosphor-coated metal plate which is enclosed in a grounded U-channel that provides electrostatic shielding. An adjustable accelerating voltage is applied to the metal plate to greatly increase the cathodoluminescence produced by the directed electron beam from an electron gun, and the visible electron-beam image is recorded by a CCD camera. The gain in the image brightness allows significant reduction of the electron-beam energy to minimize the deviation of the measured drift surfaces from the true magnetic surfaces, and to improve resolution for detailed studies of surfaces in the newer stellarator experiments. This technique is particularly suited to electron energies below the phosphor activation threshold, when external image intensifying systems are likely to be very inefficient. Up to 36 toroidal rotations have been observed, limited mainly by the effective cross sections of the fluorescent probe and the electron gun. Mapping at low magnetic field strengths allows detection of small fixed amplitude field errors. Measurements of the gain characteristics and resolution are presented, with an example of the electrically variable resolution achievable with this design. The effect of electron energy on drift surfaces of a heliac is demonstrated.

  1. Molecular probes for nonlinear optical imaging of biological membranes

    NASA Astrophysics Data System (ADS)

    Blanchard-Desce, Mireille H.; Ventelon, Lionel; Charier, Sandrine; Moreaux, Laurent; Mertz, Jerome

    2001-12-01

    Second-harmonic generation (SHG) and two-photon excited fluorescence (TPEF) are nonlinear optical (NLO) phenomena that scale with excitation intensity squared, and hence give rise to an intrinsic 3-dimensional resolution when used in microscopic imaging. TPEF microscopy has gained widespread popularity in the biology community whereas SHG microscopy promises to be a powerful tool because of its sensitivity to local asymmetry. We have implemented an approach toward the design of NLO-probes specifically adapted for SHG and/or TPEF imaging of biological membranes. Our strategy is based on the design of nanoscale amphiphilic NLO-phores. We have prepared symmetrical bolaamphiphilic fluorophores combining very high two-photon absorption (TPA) cross-sections in the visible red region and affinity for cellular membranes. Their incorporation and orientation in lipid membranes can be monitored via TPEF anisotropy. We have also prepared amphiphilic push-pull chromophores exhibiting both large TPA cross-sections and very large first hyperpolarizabilities in the near-IR region. These NLO-probes have proved to be particularly useful for imaging of biological membranes by simultaneous SHG and TPEF microscopy and offer attractive prospects for real-time imaging of fundamental biological processes such as adhesion, fusion or reporting of membrane potentials.

  2. Photonic Doppler velocimetry lens array probe incorporating stereo imaging

    SciTech Connect

    Malone, Robert M.; Kaufman, Morris I.

    2015-09-01

    A probe including a multiple lens array is disclosed to measure velocity distribution of a moving surface along many lines of sight. Laser light, directed to the moving surface is reflected back from the surface and is Doppler shifted, collected into the array, and then directed to detection equipment through optic fibers. The received light is mixed with reference laser light and using photonic Doppler velocimetry, a continuous time record of the surface movement is obtained. An array of single-mode optical fibers provides an optic signal to the multiple lens array. Numerous fibers in a fiber array project numerous rays to establish many measurement points at numerous different locations. One or more lens groups may be replaced with imaging lenses so a stereo image of the moving surface can be recorded. Imaging a portion of the surface during initial travel can determine whether the surface is breaking up.

  3. Band Excitation in Scanning Probe Microscopy: Recognition and Functional Imaging

    SciTech Connect

    Jesse, Stephen; Vasudevan, Dr. Rama; Collins, Liam; Strelcov, Evgheni; Okatan, Mahmut B; Belianinov, Alex; Baddorf, Arthur P; Proksch, Roger; Kalinin, Sergei V

    2014-01-01

    Field confinement at the junction between a biased scanning probe microscope s (SPM) tip and solid surface enables local probing of various bias-induced transformations such as polarization switching, ionic motion, or electrochemical reactions to name a few. The nanoscale size of the biased region is smaller or comparable to features like grain boundaries and dislocations, potentially allows for the study of kinetics and thermodynamics at the level of a single defect. In contrast to classical statistically averaged approaches, this allows one to link structure to functionality and deterministically decipher associated mesoscopic and atomistic mechanisms. Furthermore, this type of information can serve as a fingerprint of local material functionality, allowing for local recognition imaging. Here, current progress in multidimensional SPM techniques based on band-excitation time and voltage spectroscopies is illustrated, including discussions on data acquisition, dimensionality reduction, and visualization along with future challenges and opportunities for the field.

  4. Photodynamic molecular beacon as an activatable photosensitizer based on protease-controlled singlet oxygen quenching and activation.

    PubMed

    Zheng, Gang; Chen, Juan; Stefflova, Klara; Jarvi, Mark; Li, Hui; Wilson, Brian C

    2007-05-22

    Molecular beacons are FRET-based target-activatable probes. They offer control of fluorescence emission in response to specific cancer targets, thus are useful tools for in vivo cancer imaging. Photodynamic therapy (PDT) is a cell-killing process by light activation of a photosensitizer (PS) in the presence of oxygen. The key cytotoxic agent is singlet oxygen ((1)O(2)). By combining these two principles (FRET and PDT), we have introduced a concept of photodynamic molecular beacons (PMB) for controlling the PS's ability to generate (1)O(2) and, ultimately, for controlling its PDT activity. The PMB comprises a disease-specific linker, a PS, and a (1)O(2) quencher, so that the PS's photoactivity is silenced until the linker interacts with a target molecule, such as a tumor-associated protease. Here, we report the full implementation of this concept by synthesizing a matrix metalloproteinase-7 (MMP7)-triggered PMB and achieving not only MMP7-triggered production of (1)O(2) in solution but also MMP7-mediated photodynamic cytotoxicity in cancer cells. Preliminary in vivo studies also reveal the MMP7-activated PDT efficacy of this PMB. This study validates the core principle of the PMB concept that selective PDT-induced cell death can be achieved by exerting precise control of the PS's ability to produce (1)O(2) by responding to specific cancer-associated biomarkers. Thus, PDT selectivity will no longer depend solely on how selectively the PS can be delivered to cancer cells. Rather, it will depend on how selective a biomarker is to cancer cells, and how selective the interaction of PMB is to this biomarker.

  5. Ultrasound and fluoroscopic images fusion by autonomous ultrasound probe detection.

    PubMed

    Mountney, Peter; Ionasec, Razvan; Kaizer, Markus; Mamaghani, Sina; Wu, Wen; Chen, Terrence; John, Matthias; Boese, Jan; Comaniciu, Dorin

    2012-01-01

    New minimal-invasive interventions such as transcatheter valve procedures exploit multiple imaging modalities to guide tools (fluoroscopy) and visualize soft tissue (transesophageal echocardiography (TEE)). Currently, these complementary modalities are visualized in separate coordinate systems and on separate monitors creating a challenging clinical workflow. This paper proposes a novel framework for fusing TEE and fluoroscopy by detecting the pose of the TEE probe in the fluoroscopic image. Probe pose detection is challenging in fluoroscopy and conventional computer vision techniques are not well suited. Current research requires manual initialization or the addition of fiducials. The main contribution of this paper is autonomous six DoF pose detection by combining discriminative learning techniques with a fast binary template library. The pose estimation problem is reformulated to incrementally detect pose parameters by exploiting natural invariances in the image. The theoretical contribution of this paper is validated on synthetic, phantom and in vivo data. The practical application of this technique is supported by accurate results (< 5 mm in-plane error) and computation time of 0.5s.

  6. Ultrasound and fluoroscopic images fusion by autonomous ultrasound probe detection.

    PubMed

    Mountney, Peter; Ionasec, Razvan; Kaizer, Markus; Mamaghani, Sina; Wu, Wen; Chen, Terrence; John, Matthias; Boese, Jan; Comaniciu, Dorin

    2012-01-01

    New minimal-invasive interventions such as transcatheter valve procedures exploit multiple imaging modalities to guide tools (fluoroscopy) and visualize soft tissue (transesophageal echocardiography (TEE)). Currently, these complementary modalities are visualized in separate coordinate systems and on separate monitors creating a challenging clinical workflow. This paper proposes a novel framework for fusing TEE and fluoroscopy by detecting the pose of the TEE probe in the fluoroscopic image. Probe pose detection is challenging in fluoroscopy and conventional computer vision techniques are not well suited. Current research requires manual initialization or the addition of fiducials. The main contribution of this paper is autonomous six DoF pose detection by combining discriminative learning techniques with a fast binary template library. The pose estimation problem is reformulated to incrementally detect pose parameters by exploiting natural invariances in the image. The theoretical contribution of this paper is validated on synthetic, phantom and in vivo data. The practical application of this technique is supported by accurate results (< 5 mm in-plane error) and computation time of 0.5s. PMID:23286091

  7. Nondestructive millimeter wave imaging and spectroscopy using dielectric focusing probes

    SciTech Connect

    Hejase, Jose A.; Shane, Steven S.; Park, Kyoung Y.; Chahal, Premjeet

    2014-02-18

    A tool for interrogating objects over a wide band of frequencies with subwavelength resolution at small standoff distances (near field region) in the transmission mode using a single source and detector measurement setup in the millimeter wave band is presented. The design utilizes optics like principles for guiding electromagnetic millimeter waves from large cross-sectional areas to considerably smaller sub-wavelength areas. While plano-convex lenses can be used to focus waves to a fine resolution, they usually require a large stand-off distance thus resulting in alignment and spacing issues. The design procedure and simulation analysis of the focusing probes are presented in this study along with experimental verification of performance and imaging and spectroscopy examples. Nondestructive evaluation will find benefit from such an apparatus including biological tissue imaging, electronic package integrity testing, composite dielectric structure evaluation for defects and microfluidic sensing.

  8. Crystallographic Image Processing Software for Scanning Probe Microscopists

    NASA Astrophysics Data System (ADS)

    Plachinda, Pavel; Moon, Bill; Moeck, Peter

    2010-03-01

    Following the common practice of structural electron crystallography, scanning probe microscopy (SPM) images can be processed ``crystallographically'' [1,2]. An estimate of the point spread function of the SPM can be obtained and subsequently its influence removed from the images. Also a difference Fourier synthesis can be calculated in order to enhance the visibility of structural defects. We are currently in the process of developing dedicated PC-based software for the wider SPM community. [4pt] [1] P. Moeck, B. Moon Jr., M. Abdel-Hafiez, and M. Hietschold, Proc. NSTI 2009, Houston, May 3-7, 2009, Vol. I (2009) 314-317, (ISBN: 978-1-4398-1782-7). [0pt] [2] P. Moeck, M. Toader, M. Abdel-Hafiez, and M. Hietschold, Proc. 2009 International Conference on Frontiers of Characterization and Metrology for Nanoelectronics, May 11-14, 2009, Albany, New York, Best Paper Award

  9. Artist: Ken Hodges Composite image explaining Objective and Motivation for Galileo Probe Heat Loads:

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Artist: Ken Hodges Composite image explaining Objective and Motivation for Galileo Probe Heat Loads: Galileo Probe descending into Jupiters Atmosphere shows heat shield separation with parachute deployed. (Ref. JPL P-19180)

  10. Model Mismatch Paradigm for Probe based Nanoscale Imaging

    NASA Astrophysics Data System (ADS)

    Agarwal, Pranav

    Scanning Probe Microscopes (SPMs) are widely used for investigation of material properties and manipulation of matter at the nanoscale. These instruments are considered critical enablers of nanotechnology by providing the only technique for direct observation of dynamics at the nanoscale and affecting it with sub Angstrom resolution. Current SPMs are limited by low throughput and lack of quantitative measurements of material properties. Various applications like the high density data storage, sub-20 nm lithography, fault detection and functional probing of semiconductor circuits, direct observation of dynamical processes involved in biological samples viz. motor proteins and transport phenomena in various materials demand high throughput operation. Researchers involved in material characterization at nanoscale are interested in getting quantitative measurements of stiffness and dissipative properties of various materials in a least invasive manner. In this thesis, system theoretic concepts are used to address these limitations. The central tenet of the thesis is to model, the known information about the system and then focus on perturbations of these known dynamics or model, to sense the effects due to changes in the environment such as changes in material properties or surface topography. Thus a model mismatch paradigm for probe based nanoscale imaging is developed. The topic is developed by presenting physics based modeling of a particular mode of operation of SPMs called the dynamic mode operation. This mode is modeled as a forced Lure system where a linear time invariant system is in feedback with an unknown static memoryless nonlinearity. Tools from averaging theory are used to tame this complex nonlinear system by approximating it as a linear system with time varying parameters. Material properties are thus transformed from being parameters of unknown nonlinear functions to being unknown coefficients of a linear plant. The first contribution of this thesis

  11. Microfluidics for Positron Emission Tomography (PET) Imaging Probe Development

    PubMed Central

    Wang, Ming-Wei; Lin, Wei-Yu; Liu, Kan; Masterman-Smith, Michael; Shen, Clifton Kwang-Fu

    2012-01-01

    Due to increased needs for Positron Emission Tomography (PET) scanning, high demands for a wide variety of radiolabeled compounds will have to be met by exploiting novel radiochemistry and engineering technologies to improve the production and development of PET probes. The application of microfluidic reactors to perform radiosyntheses is currently attracting a great deal of interest because of their potential to deliver many advantages over conventional labeling systems. Microfluidic-based radiochemistry can lead to the use of smaller quantities of precursors, accelerated reaction rates and easier purification processes with greater yield and higher specific activity of desired probes. Several ‘proof-of-principle’ examples, along with basics of device architecture and operation, and potential limitations of each design are discussed here. Along with the concept of radioisotope distribution from centralized cyclotron facilities to individual imaging centers and laboratories (“decentralized model”), an easy-to-use, standalone, flexible, fully-automated radiochemical microfluidic platform can open up to simpler and more cost-effective procedures for molecular imaging using PET. PMID:20643021

  12. Exogenous Molecular Probes for Targeted Imaging in Cancer: Focus on Multi-modal Imaging

    PubMed Central

    Joshi, Bishnu P.; Wang, Thomas D.

    2010-01-01

    Cancer is one of the major causes of mortality and morbidity in our healthcare system. Molecular imaging is an emerging methodology for the early detection of cancer, guidance of therapy, and monitoring of response. The development of new instruments and exogenous molecular probes that can be labeled for multi-modality imaging is critical to this process. Today, molecular imaging is at a crossroad, and new targeted imaging agents are expected to broadly expand our ability to detect and manage cancer. This integrated imaging strategy will permit clinicians to not only localize lesions within the body but also to manage their therapy by visualizing the expression and activity of specific molecules. This information is expected to have a major impact on drug development and understanding of basic cancer biology. At this time, a number of molecular probes have been developed by conjugating various labels to affinity ligands for targeting in different imaging modalities. This review will describe the current status of exogenous molecular probes for optical, scintigraphic, MRI and ultrasound imaging platforms. Furthermore, we will also shed light on how these techniques can be used synergistically in multi-modal platforms and how these techniques are being employed in current research. PMID:22180839

  13. Evaluation of improvement of diffuse optical imaging of brain function by high-density probe arrangements and imaging algorithms

    NASA Astrophysics Data System (ADS)

    Sakakibara, Yusuke; Kurihara, Kazuki; Okada, Eiji

    2016-04-01

    Diffuse optical imaging has been applied to measure the localized hemodynamic responses to brain activation. One of the serious problems with diffuse optical imaging is the limitation of the spatial resolution caused by the sparse probe arrangement and broadened spatial sensitivity profile for each probe pair. High-density probe arrangements and an image reconstruction algorithm considering the broadening of the spatial sensitivity can improve the spatial resolution of the image. In this study, the diffuse optical imaging of the absorption change in the brain is simulated to evaluate the effect of the high-density probe arrangements and imaging methods. The localization error, equivalent full-width half maximum and circularity of the absorption change in the image obtained by the mapping and reconstruction methods from the data measured by five probe arrangements are compared to quantitatively evaluate the imaging methods and probe arrangements. The simple mapping method is sufficient for the density of the measurement points up to the double-density probe arrangement. The image reconstruction method considering the broadening of the spatial sensitivity of the probe pairs can effectively improve the spatial resolution of the image obtained from the probe arrangements higher than the quadruple density, in which the distance between the neighboring measurement points is 10.6 mm.

  14. Gadolinium-Encapsulating Iron Oxide Nanoprobe as Activatable NMR/MRI Contrast Agent

    PubMed Central

    Santra, Santimukul; Jativa, Samuel D.; Kaittanis, Charalambos; Normand, Guillaume; Grimm, Jan; Perez, J. Manuel

    2012-01-01

    Herein we report a novel gadolinium-encapsulating iron oxide nanoparticle-based activatable NMR/MRI nanoprobe. In our design, Gd-DTPA is encapsulated within the polyacrylic acid (PAA) polymer coating of a superparamagnetic iron oxide nanoparticle (IO-PAA) yielding a composite magnetic nanoprobe (IO-PAA-Gd-DTPA) with quenched longitudinal spin-lattice magnetic relaxation (T1). Upon release of the Gd-DTPA complex from the nanoprobe's polymeric coating in acidic media, an increase in the T1 relaxation rate (1/T1) of the composite magnetic nanoprobe was observed, indicating a dequenching of the nanoprobe with a corresponding increase in the T1-weighted MRI signal. When a folate-conjugated nanoprobe was incubated in HeLa cells, a cancer cell line overexpressing folate receptors, an increase in the 1/T1 signal was observed. This result suggests that upon receptor-mediated internalization, the composite magnetic nanoprobe degraded within the cell's lysosome acidic (pH = 5.0) environment, resulting in an intracellular release of Gd-DTPA complex with subsequent T1 activation. No change in T1 was observed when the Gd-DTPA complex was chemically conjugated on the surface of the nanoparticle's polymeric coating or when encapsulated in the polymeric coating of a non-magnetic nanoparticle. These results confirmed that the observed (T1) quenching of the composite magnetic nanoprobe is due to the encapsulation and close proximity of the Gd ion to the nanoparticles superparamagnetic iron oxide (IO) core. In addition, when an anticancer drug (Taxol) was co-encapsulated with the Gd-DTPA within the folate receptor targeting composite magnetic nanoprobe, the T1 activation of the probe coincide with the rate of drug release and corresponding cytotoxic effect in cell culture studies. Taken together, these results suggest that our activatable T1 nanoagent could be of great importance for the detection of acidic tumors and assessment of drug targeting and release by MRI. PMID:22809405

  15. Gadolinium-encapsulating iron oxide nanoprobe as activatable NMR/MRI contrast agent.

    PubMed

    Santra, Santimukul; Jativa, Samuel D; Kaittanis, Charalambos; Normand, Guillaume; Grimm, Jan; Perez, J Manuel

    2012-08-28

    Herein we report a novel gadolinium-encapsulating iron oxide nanoparticle-based activatable NMR/MRI nanoprobe. In our design, Gd-DTPA is encapsulated within the poly(acrylic acid) (PAA) polymer coating of a superparamagnetic iron oxide nanoparticle (IO-PAA), yielding a composite magnetic nanoprobe (IO-PAA-Gd-DTPA) with quenched longitudinal spin-lattice magnetic relaxation (T(1)). Upon release of the Gd-DTPA complex from the nanoprobe's polymeric coating in acidic media, an increase in the T(1) relaxation rate (1/T(1)) of the composite magnetic nanoprobe was observed, indicating a dequenching of the nanoprobe with a corresponding increase in the T(1)-weighted MRI signal. When a folate-conjugated nanoprobe was incubated in HeLa cells, a cancer cell line overexpressing folate receptors, an increase in the 1/T(1) signal was observed. This result suggests that, upon receptor-mediated internalization, the composite magnetic nanoprobe degraded within the cell's lysosome acidic (pH 5.0) environment, resulting in an intracellular release of Gd-DTPA complex with subsequent T(1) activation. In addition, when an anticancer drug (Taxol) was coencapsulated with the Gd-DTPA within the folate receptor targeting composite magnetic nanoprobe, the T(1) activation of the probe coincided with the rate of drug release and corresponding cytotoxic effect in cell culture studies. Taken together, these results suggest that our activatable T(1) nanoagent could be of great importance for the detection of acidic tumors and assessment of drug targeting and release by MRI.

  16. Endoscopic optical coherence tomography imaging probe using a MEMS actuator

    NASA Astrophysics Data System (ADS)

    Zara, Jason M.; Izatt, Joseph A.; Oberhardt, Bruce J.; Smith, Stephen W.

    2004-07-01

    Endoscopic optical coherence tomography (EOCT) is a medical imaging technique that uses infrared light delivered via an endoscope to produce high-resolution images of tissue microstructure of the gastrointestinal tract. A key component of an EOCT system is the method used to scan the infrared beam across the tissue surface. We have begun developing electrostatic MEMS micromirror devices for use in EOCT. These devices consist of 1 mm square gold-plated silicon mirrors on polyimide tables that tilt on 3 micron thick torsion hinges. The MEMS actuator used to tilt the mirror, the integrated forces array (IFA) is a thin (2.2 μm) polyimide membrane consisting of hundreds of thousands of deformable capacitors that can produce strains up to 20% and forces equivalent to 13 mg with applied voltages from 30-120 V. Measurements of optical deflections of these devices range from 18° at low frequencies to more than 120° near the resonant frequencies of the structures (30-60 Hz). The support structures, hinges, and actuators are fabricated from polyimide on silicon using photolithography. These electrostatic MEMS micromirrors were inserted into the scanning arm of an OCT imaging system to take in vitro images of porcine tissue and in vivo images of human skin at frame rates from 4-8 Hz. SLA probe tips were designed and fabricated to align the optics of the device and to protect the fragile polyimide devices during endoscopic imaging. In addition, devices are being fabricated that combine the IFA and mirror structures onto a single silicon wafer, reducing fabrication difficulty.

  17. Molecular Imaging of Proteases in Cancer

    PubMed Central

    Yang, Yunan; Hong, Hao; Zhang, Yin; Cai, Weibo

    2010-01-01

    Proteases play important roles during tumor angiogenesis, invasion, and metastasis. Various molecular imaging techniques have been employed for protease imaging: optical (both fluorescence and bioluminescence), magnetic resonance imaging (MRI), single-photon emission computed tomography (SPECT), and positron emission tomography (PET). In this review, we will summarize the current status of imaging proteases in cancer with these techniques. Optical imaging of proteases, in particular with fluorescence, is the most intensively validated and many of the imaging probes are already commercially available. It is generally agreed that the use of activatable probes is the most accurate and appropriate means for measuring protease activity. Molecular imaging of proteases with other techniques (i.e. MRI, SPECT, and PET) has not been well-documented in the literature which certainly deserves much future effort. Optical imaging and molecular MRI of protease activity has very limited potential for clinical investigation. PET/SPECT imaging is suitable for clinical investigation; however the optimal probes for PET/SPECT imaging of proteases in cancer have yet to be developed. Successful development of protease imaging probes with optimal in vivo stability, tumor targeting efficacy, and desirable pharmacokinetics for clinical translation will eventually improve cancer patient management. Not limited to cancer, these protease-targeted imaging probes will also have broad applications in other diseases such as arthritis, atherosclerosis, and myocardial infarction. PMID:20234801

  18. Positrons as imaging agents and probes in nanotechnology

    NASA Astrophysics Data System (ADS)

    Smith, Suzanne V.

    2009-09-01

    Positron emission tomography (PET) tracks a positron emitting radiopharmaceutical injected into the body and generates a 3-dimensional image of its location. Introduced in the early 70s, it has now developed into a powerful medical diagnostic tool for routine clinical use as well as in drug development. Unrivalled as a highly sensitive, specific and non-invasive imaging tool, PET unfortunately lacks the resolution of Computer Tomography (CT) and Magnetic Resonance Imaging (MRI). As the resolution of PET depends significantly on the energy of the positron incorporated in the radiopharmaceutical and its interaction with its surrounding tissue, there is growing interest in expanding our understanding of how positrons interact at the atomic and molecular level. A better understanding of these interactions will contribute to improving the resolution of PET and assist in the design of better imaging agents. Positrons are also used in Positron Annihilation Lifetime Spectroscopy (PALS) to determine electron density and or presence and incidence of micro- and mesopores (0.1 to 10 nm) in materials. The control of porosity in engineered materials is crucial for applications such as controlled release or air and water resistant films. Equally important to the design of nano and microtechnologies, is our understanding of the microenvironments within these pores and on surfaces. Hence as radiopharmaceuticals are designed to track disease, nuclear probes (radioactive molecules) are synthesized to investigate the chemical properties within these pores. This article will give a brief overview of the present role of positrons in imaging as well as explore its potential to contribute in the engineering of new materials to the marketplace.

  19. Genetically encoded optical probes for imaging cellular signaling pathways.

    PubMed

    Umezawa, Yoshio

    2005-06-15

    The intracellular signaling can be monitored in vivo in living cells by genetically encoded intracellular fluorescent and bioluminescent probes or indicators, which include second messengers, protein phosphorylation, protein conformational changes, protein-protein interactions, and protein localizations. These probes are of general use not only for fundamental biological studies, but also for assay and screening of possible pharmaceutical or toxic chemicals that inhibit or facilitate cellular signaling pathways. In this review, two examples of such indicators were briefly introduced. First, a genetically encoded fluorescent indicator was described for the detection and characterization of estrogen agonists and antagonists. The indicator was named SCCoR (single cell-coactivator recruitment). The high sensitivity of the present indicator made it possible to distinguish between estrogen strong and weak agonists in a dose-dependent fashion, immediately after adding a ligand to live cells. Discrimination of agonists from antagonists was efficiently achieved using the indicator. The approach described here can be applied to develop biosensors for other hormone receptors as well. Another example herein is a genetically encoded bioluminescent indicator for monitoring the nuclear trafficking of target proteins in vitro and in vivo. We demonstrated quantitative cell-based in vitro sensing of ligand-induced translocation of androgen receptor, which allowed high-throughput screening of exo- and endogenous agonists and antagonists. Furthermore, the indicator enabled noninvasive in vivo imaging of the androgen receptor translocation in the brains of living mice with a charge-coupled device imaging system. These rapid and quantitative analyses in vitro and in vivo provide a wide variety of applications for screening pharmacological or toxicological compounds and testing them in living animals.

  20. Atomic Force Microscope Controlled Topographical Imaging and Proximal Probe Thermal Desorption/Ionization Mass Spectrometry Imaging

    SciTech Connect

    Ovchinnikova, Olga S; Kjoller, Kevin; Hurst, Gregory {Greg} B; Pelletier, Dale A; Van Berkel, Gary J

    2014-01-01

    This paper reports on the development of a hybrid atmospheric pressure atomic force microscopy/mass spectrometry imaging system utilizing nano-thermal analysis probes for thermal desorption surface sampling with subsequent atmospheric pressure chemical ionization and mass analysis. The basic instrumental setup and the general operation of the system were discussed and optimized performance metrics were presented. The ability to correlate topographic images of a surface with atomic force microscopy and a mass spectral chemical image of the same surface, utilizing the same probe without moving the sample from the system, was demonstrated. Co-registered mass spectral chemical images and atomic force microscopy topographical images were obtained from inked patterns on paper as well as from a living bacterial colony on an agar gel. Spatial resolution of the topography images based on pixel size (0.2 m x 0.8 m) was better than the resolution of the mass spectral images (2.5 m x 2.0 m), which were limited by current mass spectral data acquisition rate and system detection levels.

  1. A Dream of a Mission: Stellar Imager and Seismic Probe

    NASA Technical Reports Server (NTRS)

    Carpenter, Kenneth G.; Schrijver, Carolus J.; Fisher, Richard R. (Technical Monitor)

    2000-01-01

    The Stellar Imager and Seismic Probe (SISP) is a mission to understand the various effects of magnetic fields of stars, the dynamos that generate them, and the internal structure and dynamics of the stars in which they exist. The ultimate goal is to achieve the best-possible forecasting of solar activity on times scales ranging up to decades, and an understanding of the impact of stellar magnetic activity on astrobiology and life in the Universe. The road to that goal will revolutionize our understanding of stars and stellar systems, the building blocks of the Universe. SISP will zoom in on what today - with few exceptions - we only know as point sources, revealing processes never before seen, thus providing a tool to astrophysics as fundamental as the microscope is to the study of life on Earth. SISP is an ultraviolet aperture-synthesis imager with 8-10 telescopes with meter-class apertures, and a central hub with focal-plane instrumentation that allows spectrophotometry in passbands as narrow as a few Angstroms up to hundreds of Angstroms. SISP will image stars and binaries with one hundred to one thousand resolution elements on their surface, and sound their interiors through asteroseismology to image internal structure, differential rotation, and large-scale circulations; this will provide accurate knowledge of stellar structure and evolution and complex transport processes, and will impact numerous branches of (astro)physics ranging from the Big Bang to the future of the Universe. Fitting naturally within the NASA long-term time line, SISP complements defined missions, and with them will show us entire other solar systems, from the central star to their orbiting planets.

  2. Evanescent Microwave Probes Using Coplanar Waveguide and Stripline for Super-Resolution Imaging of Materials

    NASA Technical Reports Server (NTRS)

    Ponchak, G. E.; Akinwande, D.; Ciocan, R.; LeClair, S. R.; Tabib-Azar, M.

    2000-01-01

    An evanescent field microwave imaging probe based on half-wavelength, microwave transmission line resonators is described. Optimization of the probe tip design, the coupling gap, and the data analysis has resulted in images of metal lines on semiconductor substrates with 2.6 microns spatial resolution and a minimum detectable line width of 0.4 microns at 1 GHz.

  3. Reaction-based two-photon probes for mercury ions: fluorescence imaging with dual optical windows.

    PubMed

    Rao, Alla Sreenivasa; Kim, Dokyoung; Wang, Taejun; Kim, Ki Hean; Hwang, Sekyu; Ahn, Kyo Han

    2012-05-18

    For fluorescent imaging of mercury ions in living species, two-photon probes with dual optical windows are in high demand but remain unexplored. Several dithioacetals were evaluated, and a probe was found, which, upon reaction with mercury species, yielded a two-photon dye; this conversion accompanies ratiometric emission changes with a 97-nm shift, enabling fluorescent imaging of both the probe and mercury ions in cells by one- and two-photon microscopy for the first time.

  4. Photo-activatable Cre recombinase regulates gene expression in vivo.

    PubMed

    Schindler, Suzanne E; McCall, Jordan G; Yan, Ping; Hyrc, Krzystof L; Li, Mingjie; Tucker, Chandra L; Lee, Jin-Moo; Bruchas, Michael R; Diamond, Marc I

    2015-01-01

    Techniques allowing precise spatial and temporal control of gene expression in the brain are needed. Herein we describe optogenetic approaches using a photo-activatable Cre recombinase (PA-Cre) to stably modify gene expression in the mouse brain. Blue light illumination for 12 hours via optical fibers activated PA-Cre in the hippocampus, a deep brain structure. Two-photon illumination through a thinned skull window for 100 minutes activated PA-Cre within a sub-millimeter region of cortex. Light activation of PA-Cre may allow permanent gene modification with improved spatiotemporal precision compared to standard methods. PMID:26350769

  5. Photo-activatable Cre recombinase regulates gene expression in vivo

    PubMed Central

    Schindler, Suzanne E.; McCall, Jordan G.; Yan, Ping; Hyrc, Krzystof L.; Li, Mingjie; Tucker, Chandra L.; Lee, Jin-Moo; Bruchas, Michael R.; Diamond, Marc I.

    2015-01-01

    Techniques allowing precise spatial and temporal control of gene expression in the brain are needed. Herein we describe optogenetic approaches using a photo-activatable Cre recombinase (PA-Cre) to stably modify gene expression in the mouse brain. Blue light illumination for 12 hours via optical fibers activated PA-Cre in the hippocampus, a deep brain structure. Two-photon illumination through a thinned skull window for 100 minutes activated PA-Cre within a sub-millimeter region of cortex. Light activation of PA-Cre may allow permanent gene modification with improved spatiotemporal precision compared to standard methods. PMID:26350769

  6. Photo-activatable Cre recombinase regulates gene expression in vivo.

    PubMed

    Schindler, Suzanne E; McCall, Jordan G; Yan, Ping; Hyrc, Krzystof L; Li, Mingjie; Tucker, Chandra L; Lee, Jin-Moo; Bruchas, Michael R; Diamond, Marc I

    2015-09-09

    Techniques allowing precise spatial and temporal control of gene expression in the brain are needed. Herein we describe optogenetic approaches using a photo-activatable Cre recombinase (PA-Cre) to stably modify gene expression in the mouse brain. Blue light illumination for 12 hours via optical fibers activated PA-Cre in the hippocampus, a deep brain structure. Two-photon illumination through a thinned skull window for 100 minutes activated PA-Cre within a sub-millimeter region of cortex. Light activation of PA-Cre may allow permanent gene modification with improved spatiotemporal precision compared to standard methods.

  7. Compact probing system using remote imaging for industrial plant maintenance

    NASA Astrophysics Data System (ADS)

    Ito, F.; Nishimura, A.

    2014-03-01

    Laser induced breakdown spectroscopy (LIBS) and endoscope observation were combined to design a remote probing device. We use this probing device to inspect a crack of the inner wall of the heat exchanger. Crack inspection requires speed at first, and then it requires accuracy. Once Eddy Current Testing (ECT) finds a crack with a certain signal level, another method should confirm it visually. We are proposing Magnetic particle Testing (MT) using specially fabricated the Magnetic Particle Micro Capsule (MPMC). For LIBS, a multichannel spectrometer and a Q-switch YAG laser were used. Irradiation area is 270 μm, and the pulse energy was 2 mJ. This pulse energy corresponds to 5-2.2 MW/cm2. A composite-type optical fiber was used to deliver both laser energy and optical image. Samples were prepared to heat a zirconium alloy plate by underwater arc welding in order to demonstrate severe accidents of nuclear power plants. A black oxide layer covered the weld surface and white particles floated on water surface. Laser induced breakdown plasma emission was taken into the spectroscope using this optical fiber combined with telescopic optics. As a result, we were able to simultaneously perform spectroscopic measurement and observation. For MT, the MPMC which gathered in the defective area is observed with this fiber. The MPMC emits light by the illumination of UV light from this optical fiber. The size of a defect is estimated with this amount of emission. Such technology will be useful for inspection repair of reactor pipe.

  8. Lysosome targeting fluorescence probe for imaging intracellular thiols.

    PubMed

    Kand, Dnyaneshwar; Saha, Tanmoy; Lahiri, Mayurika; Talukdar, Pinaki

    2015-08-14

    A BODIPY-based fluorescence turn-on probe, exhibiting high selectivity and sensitivity towards intracellular thiols with excellent lysosomal localization is reported. The probe displayed fast response towards biothiols in aqueous solution. Localization of the probe in lysosome was demonstrated by intracellular colocalization studies with the aid of LysoSensor Green.

  9. Co-encapsulating the fusogenic peptide INF7 and molecular imaging probes in liposomes increases intracellular signal and probe retention.

    PubMed

    Burks, Scott R; Legenzov, Eric A; Martin, Erik W; Li, Changqing; Lu, Wuyuan; Kao, Joseph P Y

    2015-01-01

    Liposomes are promising vehicles to deliver diagnostic and therapeutic agents to cells in vivo. After uptake into cells by endocytosis, liposomes are degraded in the endolysosomal system. Consequently, the encapsulated cargo molecules frequently remain sequestered in endosomal compartments; this limits their usefulness in many applications (e.g. gene delivery). To overcome this, various fusogenic peptides have been developed to facilitate delivery of liposomally-encapsulated molecules into the cytosol. One such peptide is the pH-sensitive influenza-derived peptide INF7. Liposomal delivery of imaging agents is an attractive approach for enabling cell imaging and cell tracking in vivo, but can be hampered by inadequate intracellular accumulation and retention of probes caused by exocytosis (and possible degradation) of endosome-entrapped probes. Such signal loss could be minimized by facilitating escape of probe molecules from endolysosomal compartments into the cytosol. We investigated the ability of co-encapsulated INF7 to release liposomally-delivered rhodamine fluorophores into the cytosol after endosomal acidification/maturation. We co-encapsulated INF7 and fluorescent rhodamine derivatives having vastly different transport properties to show that after endocytosis by CV1 cells, the INF7 peptide is activated by acidic endosomal pH and facilitates efficient release of the fluorescent tracers into the cytosol. Furthermore, we show that INF7-facilitated escape from endosomes markedly enhanced retention of tracers that cannot be actively extruded from the cytosol. Minimizing loss of intracellular probes improves cellular imaging by increasing the signal-to-noise ratio of images and lengthening the time window that imaging can be performed. In particular, this will enhance in vivo electron paramagnetic resonance imaging, an emergent magnetic resonance imaging modality requires exogenous paramagnetic imaging agents and is highly promising for cellular and molecular

  10. Dedicated mobile high resolution prostate PET imager with an insertable transrectal probe

    DOEpatents

    Majewski, Stanislaw; Proffitt, James

    2010-12-28

    A dedicated mobile PET imaging system to image the prostate and surrounding organs. The imaging system includes an outside high resolution PET imager placed close to the patient's torso and an insertable and compact transrectal probe that is placed in close proximity to the prostate and operates in conjunction with the outside imager. The two detector systems are spatially co-registered to each other. The outside imager is mounted on an open rotating gantry to provide torso-wide 3D images of the prostate and surrounding tissue and organs. The insertable probe provides closer imaging, high sensitivity, and very high resolution predominately 2D view of the prostate and immediate surroundings. The probe is operated in conjunction with the outside imager and a fast data acquisition system to provide very high resolution reconstruction of the prostate and surrounding tissue and organs.

  11. High-resolution coregistered intravascular imaging with integrated ultrasound and optical coherence tomography probe

    NASA Astrophysics Data System (ADS)

    Li, Xiang; Yin, Jiechen; Hu, Changhong; Zhou, Qifa; Shung, K. Kirk; Chen, Zhongping

    2010-09-01

    We report an integrated ultrasound (US) and optical coherence tomography (OCT) probe and system for intravascular imaging. The dual-function probe is based on a 50 MHz focused ring US transducer, with a centric hole for mounting OCT probe. The coaxial US and light beams are steered by a 45° mirror to enable coregistered US/OCT imaging simultaneously. Lateral resolution of US is improved due to focused ultrasonic beam. Mirror effects on US were investigated and in vitro imaging of a rabbit aorta has been carried out. The combined US-OCT system demonstrated high resolution in visualizing superficial arterial structures while retaining deep penetration of ultrasonic imaging.

  12. High speed 3D endoscopic optical frequency domain imaging probe for lung cancer diagnosis

    NASA Astrophysics Data System (ADS)

    Li, Jianan; Feroldi, Fabio; Mo, Jianhua; Helderman, Frank; de Groot, Mattijs; de Boer, Johannes F.

    2013-06-01

    We present a miniature motorized endoscopic probe for Optical Frequency Domain Imaging with an outer diameter of 1.65 mm and a rotation speed of 3,000 - 12,500 rpm. The probe has a motorized distal end which provides a significant advantage over proximally driven probes since it does not require a drive shaft to transfer the rotational torque to the distal end of the probe and functions without a fiber rotary junction. The probe has a focal Full Width at Half Maximum of 9.6 μm and a working distance of 0.47 mm. We analyzed the non-uniform rotation distortion and found a location fluctuation of only 1.87° in repeated measurements of the same object. The probe was integrated in a high-speed Optical Frequency Domain Imaging setup at 1310 nm. We demonstrated its performance with imaging ex vivo pig bronchial and in vivo goat lung.

  13. Magnetic nanoparticles as both imaging probes and therapeutic agents.

    PubMed

    Lacroix, Lise-Marie; Ho, Don; Sun, Shouheng

    2010-01-01

    Magnetic nanoparticles (MNPs) have been explored extensively as contrast agents for magnetic resonance imaging (MRI) or as heating agents for magnetic fluid hyperthermia (MFH) [1]. To achieve optimum operation conditions in MRI and MFH, these NPs should have well-controlled magnetic properties and biological functionalities. Although numerous efforts have been dedicated to the investigations on MNPs for biomedical applications [2-5], the NP optimizations for early diagnostics and efficient therapeutics are still far from reached. Recent efforts in NP syntheses have led to some promising MNP systems for sensitive MRI and efficient MFH applications. This review summarizes these advances in the synthesis of monodisperse MNPs as both contrast probes in MRI and as therapeutic agents via MFH. It will first introduce the nanomagnetism and elucidate the critical parameters to optimize the superparamagnetic NPs for MRI and ferromagnetic NPs for MFH. It will further outline the new chemistry developed for making monodisperse MNPs with controlled magnetic properties. The review will finally highlight the NP functionalization with biocompatible molecules and biological targeting agents for tumor diagnosis and therapy. PMID:20388109

  14. Probing Field-Induced Tissue Polarization Using Transillumination Fluorescent Imaging

    PubMed Central

    Caldwell, Bryan J.; Wellner, Marcel; Mitrea, Bogdan G.; Pertsov, Arkady M.; Zemlin, Christian W.

    2010-01-01

    Despite major successes of biophysical theories in predicting the effects of electrical shocks within the heart, recent optical mapping studies have revealed two major discrepancies between theory and experiment: 1), the presence of negative bulk polarization recorded during strong shocks; and 2), the unexpectedly small surface polarization under shock electrodes. There is little consensus as to whether these differences result from deficiencies of experimental techniques, artifacts of tissue damage, or deficiencies of existing theories. Here, we take advantage of recently developed near-infrared voltage-sensitive dyes and transillumination optical imaging to perform, for the first time that we know of, noninvasive probing of field effects deep inside the intact ventricular wall. This technique removes some of the limitations encountered in previous experimental studies. We explicitly demonstrate that deep inside intact myocardial tissue preparations, strong electrical shocks do produce considerable negative bulk polarization previously inferred from surface recordings. We also demonstrate that near-threshold diastolic field stimulation produces activation of deep myocardial layers 2–6 mm away from the cathodal surface, contrary to theory. Using bidomain simulations we explore factors that may improve the agreement between theory and experiment. We show that the inclusion of negative asymmetric current can qualitatively explain negative bulk polarization in a discontinuous bidomain model. PMID:20923639

  15. Novel combined miniature optical coherence tomography ultrasound probe for in vivo intravascular imaging

    NASA Astrophysics Data System (ADS)

    Yin, Jiechen; Li, Xiang; Jing, Joe; Li, Jiawen; Mukai, David; Mahon, Sari; Edris, Ahmad; Hoang, Khiet; Shung, K. Kirk; Brenner, Matthew; Narula, Jagat; Zhou, Qifa; Chen, Zhongping

    2011-06-01

    We have developed a miniature integrated optical coherence tomography (OCT) ultrasound (US) probing system for intravascular imaging applications. In the OCT probe, the light coming out of a single mode fiber is focused by a gradient-index lens and then reflected by a right-angle prism from the side of the probe into the sample. It was combined with a 35 MHz PMN-PT side-viewing ultrasound transducer to obtain the ultrasound image as well. The OCT and ultrasound probes were integrated as a single probe to obtain OCT and ultrasound images simultaneously. The integrated probe has an outer diameter of 0.69 mm which, to our knowledge, is the smallest integrated OCT-US probe reported. Fast data acquisition and processing was implemented for real-time imaging. In vitro OCT and US images of human coronary artery with pathology, as well as in vivo images of normal rabbit abdominal aorta, were obtained using the integrated OCT-US probe to demonstrate its capability.

  16. A single probe for imaging photons, electrons and physical forces.

    PubMed

    Pilet, Nicolas; Lisunova, Yuliya; Lamattina, Fabio; Stevenson, Stephanie E; Pigozzi, Giancarlo; Paruch, Patrycja; Fink, Rainer H; Hug, Hans J; Quitmann, Christoph; Raabe, Joerg

    2016-06-10

    The combination of complementary measurement techniques has become a frequent approach to improve scientific knowledge. Pairing of the high lateral resolution scanning force microscopy (SFM) with the spectroscopic information accessible through scanning transmission soft x-ray microscopy (STXM) permits assessing physical and chemical material properties with high spatial resolution. We present progress from the NanoXAS instrument towards using an SFM probe as an x-ray detector for STXM measurements. Just by the variation of one parameter, the SFM probe can be utilised to detect either sample photo-emitted electrons or transmitted photons. This allows the use of a single probe to detect electrons, photons and physical forces of interest. We also show recent progress and demonstrate the current limitations of using a high aspect ratio coaxial SFM probe to detect photo-emitted electrons with very high lateral resolution. Novel probe designs are proposed to further progress in using an SFM probe as a STXM detector.

  17. A single probe for imaging photons, electrons and physical forces

    NASA Astrophysics Data System (ADS)

    Pilet, Nicolas; Lisunova, Yuliya; Lamattina, Fabio; Stevenson, Stephanie E.; Pigozzi, Giancarlo; Paruch, Patrycja; Fink, Rainer H.; Hug, Hans J.; Quitmann, Christoph; Raabe, Joerg

    2016-06-01

    The combination of complementary measurement techniques has become a frequent approach to improve scientific knowledge. Pairing of the high lateral resolution scanning force microscopy (SFM) with the spectroscopic information accessible through scanning transmission soft x-ray microscopy (STXM) permits assessing physical and chemical material properties with high spatial resolution. We present progress from the NanoXAS instrument towards using an SFM probe as an x-ray detector for STXM measurements. Just by the variation of one parameter, the SFM probe can be utilised to detect either sample photo-emitted electrons or transmitted photons. This allows the use of a single probe to detect electrons, photons and physical forces of interest. We also show recent progress and demonstrate the current limitations of using a high aspect ratio coaxial SFM probe to detect photo-emitted electrons with very high lateral resolution. Novel probe designs are proposed to further progress in using an SFM probe as a STXM detector.

  18. Optical imaging of reporter gene expression using a positron-emission-tomography probe

    NASA Astrophysics Data System (ADS)

    Liu, Hongguang; Ren, Gang; Liu, Shuanglong; Zhang, Xiaofen; Chen, Luxi; Han, Peizhen; Cheng, Zhen

    2010-11-01

    Reporter gene/reporter probe technology is one of the most important techniques in molecular imaging. Lately, many reporter gene/reporter probe systems have been coupled to different imaging modalities such as positron emission tomography (PET) and optical imaging (OI). It has been recently found that OI techniques could be used to monitor radioactive tracers in vitro and in living subjects. In this study, we further demonstrate that a reporter gene/nuclear reporter probe system [herpes simplex virus type-1 thymidine kinase (HSV1-tk) and 9-(4-18F-fluoro-3-[hydroxymethyl] butyl) guanine ([18F]FHBG)] could be successfully imaged by OI in vitro and in vivo. OI with radioactive reporter probes will facilitate and broaden the applications of reporter gene/reporter probe techniques in medical research.

  19. Fluorogenic Probe for the Human Ether-a-Go-Go-Related Gene Potassium Channel Imaging

    PubMed Central

    2016-01-01

    The first small-molecule fluorogenic probe A1 for imaging the human Ether-a-go-go-Related Gene (hERG) potassium channel based on the photoinduced electron transfer (PET) off–on mechanism was described herein. After careful biological evaluation, this probe had the potential of detecting and imaging the hERG channel at the molecular and cellular level. Moreover, the competitive binding mechanism of this probe would presumably minimize the effects on the electrophysiological properties of the hERG channel. Therefore, this probe may serve as a powerful toolkit to the hERG-associated study. PMID:25665091

  20. Sparse sampling and reconstruction for electron and scanning probe microscope imaging

    DOEpatents

    Anderson, Hyrum; Helms, Jovana; Wheeler, Jason W.; Larson, Kurt W.; Rohrer, Brandon R.

    2015-07-28

    Systems and methods for conducting electron or scanning probe microscopy are provided herein. In a general embodiment, the systems and methods for conducting electron or scanning probe microscopy with an undersampled data set include: driving an electron beam or probe to scan across a sample and visit a subset of pixel locations of the sample that are randomly or pseudo-randomly designated; determining actual pixel locations on the sample that are visited by the electron beam or probe; and processing data collected by detectors from the visits of the electron beam or probe at the actual pixel locations and recovering a reconstructed image of the sample.

  1. Portable LED-induced autofluorescence imager with a probe of L shape for oral cancer diagnosis

    NASA Astrophysics Data System (ADS)

    Huang, Ting-Wei; Lee, Yu-Cheng; Cheng, Nai-Lun; Yan, Yung-Jhe; Chiang, Hou-Chi; Chiou, Jin-Chern; Mang, Ou-Yang

    2015-08-01

    The difference of spectral distribution between lesions of epithelial cells and normal cells after excited fluorescence is one of methods for the cancer diagnosis. In our previous work, we developed a portable LED Induced autofluorescence (LIAF) imager contained the multiple wavelength of LED excitation light and multiple filters to capture ex-vivo oral tissue autofluorescence images. Our portable system for detection of oral cancer has a probe in front of the lens for fixing the object distance. The shape of the probe is cone, and it is not convenient for doctor to capture the oral image under an appropriate view angle in front of the probe. Therefore, a probe of L shape containing a mirror is proposed for doctors to capture the images with the right angles, and the subjects do not need to open their mouse constrainedly. Besides, a glass plate is placed in probe to prevent the liquid entering in the body, but the light reflected from the glass plate directly causes the light spots inside the images. We set the glass plate in front of LED to avoiding the light spots. When the distance between the glasses plate and the LED model plane is less than the critical value, then we can prevent the light spots caused from the glasses plate. The experiments show that the image captured with the new probe that the glasses plate placed in the back-end of the probe has no light spots inside the image.

  2. Transillumination and reflectance probes for in vivo near-IR imaging of dental caries

    NASA Astrophysics Data System (ADS)

    Simon, Jacob C.; Lucas, Seth A.; Staninec, Michal; Tom, Henry; Chan, Kenneth H.; Darling, Cynthia L.; Fried, Daniel

    2014-02-01

    Previous studies have demonstrated the utility of near infrared (NIR) imaging for caries detection employing transillumination and reflectance imaging geometries. Three intra-oral NIR imaging probes were fabricated for the acquisition of in vivo, real time videos using a high definition InGaAs SWIR camera and near-IR broadband light sources. Two transillumination probes provide occlusal and interproximal images using 1300-nm light where water absorption is low and enamel manifests the highest transparency. A third reflectance probe utilizes cross polarization and operates at >1500-nm, where water absorption is higher which reduces the reflectivity of sound tissues, significantly increasing lesion contrast. These probes are being used in an ongoing clinical study to assess the diagnostic performance of NIR imaging for the detection of caries lesions in teeth scheduled for extraction for orthodontic reasons.

  3. Imaging physical phenomena with local probes: From electrons to photons

    NASA Astrophysics Data System (ADS)

    Bonnell, Dawn A.; Basov, D. N.; Bode, Matthias; Diebold, Ulrike; Kalinin, Sergei V.; Madhavan, Vidya; Novotny, Lukas; Salmeron, Miquel; Schwarz, Udo D.; Weiss, Paul S.

    2012-07-01

    The invention of scanning tunneling and atomic force probes revolutionized our understanding of surfaces by providing real-space information about the geometric and electronic structure of surfaces at atomic spatial resolution. However, the junction of a nanometer-sized probe tip and a surface contains much more information than is intrinsic to conventional tunneling and atomic force measurements. This review summarizes recent advances that push the limits of the probing function at nanometer-scale spatial resolution in the context of important scientific problems. Issues such as molecular interface contact, superconductivity, electron spin, plasmon field focusing, surface diffusion, bond vibration, and phase transformations are highlighted as examples in which local probes elucidate complex function. The major classes of local probes are considered, including those of electromagnetic properties, electron correlations, surface structure and chemistry, optical interactions, and electromechanical coupling.

  4. Probing neutral atmospheric collision complexes with anion photoelectron imaging

    NASA Astrophysics Data System (ADS)

    Jarrold, Caroline

    Photodetachment of anionic precursors of neutral collision complexes offers a way to probe the effects of symmetry-breaking collision events on the electronic structure of normally transparent molecules. We have measured the anion photoelectron imaging (PEI) spectra of a series of O2- X complexes, where X is a volatile organic molecule with atmospheric relevance, to determine how the electronic properties of various X molecules affect the low-lying electronic structure of neutral O2 undergoing O2 - X collisons. The study was motivated by the catalog of vibrational and electronic absorption lines induced by O2 - O2, O2 - N2, and other collisions. The energies of electronic features observed in the anion PEI spectra of O2- X (X = hexane, hexene, isoprene and benzene) relative to O2- PEI spectroscopic features indicate that photodetachment of the anion does indeed access a repulsive part of the O2 - X potential. In addition, the spectra of the various complexes show an interesting variation in the intensities of transitions to the excited O2(1Δg) . X and O2(1Σg+) . X states relative to the ground O2(3Σg-) . X state. With X = non-polar species such as hexane, the relative intensities of transitions to the triplet and singlet states of O2 . X are very similar to those of isolated O2, while the relative intensity of the singlet band decreases and becomes lower in energy relative to the triplet band for X = polar molecules. A significant enhancement in the intensities of the singlet bands is observed for complexes with X = isoprene and benzene, both of which have low-lying triplet states. The role of the triplet states in isoprene and benzene, and the implications for induced electronic absorption in O2 undergoing collisions with these molecules, are explored. National Science Foundation NSF CHE 1265991.

  5. NIH workshop on clinical translation of molecular imaging probes and technology--meeting report.

    PubMed

    Liu, Christina H; Sastre, Antonio; Conroy, Richard; Seto, Belinda; Pettigrew, Roderic I

    2014-10-01

    A workshop on "Clinical Translation of Molecular Imaging Probes and Technology" was held August 2, 2013 in Bethesda, Maryland, organized and supported by the National Institute of Biomedical Imaging and Bioengineering (NIBIB). This workshop brought together researchers, clinicians, representatives from pharmaceutical companies, molecular probe developers, and regulatory science experts. Attendees met to talk over current challenges in the discovery, validation, and translation of molecular imaging (MI) probes for key clinical applications. Participants also discussed potential strategies to address these challenges. The workshop consisted of 4 sessions, with 14 presentations and 2 panel discussions. Topics of discussion included (1) challenges and opportunities for clinical research and patient care, (2) advances in molecular probe design, (3) current approaches used by industry and pharmaceutical companies, and (4) clinical translation of MI probes. In the presentations and discussions, there were general agreement that while the barriers for validation and translation of MI probes remain high, there are pressing clinical needs and development opportunities for targets in cardiovascular, cancer, endocrine, neurological, and inflammatory diseases. The strengths of different imaging modalities, and the synergy of multimodality imaging, were highlighted. Participants also underscored the continuing need for close interactions and collaborations between academic and industrial partners, and federal agencies in the imaging probe development process.

  6. High-throughput fiber-array transvaginal ultrasound/photoacoustic probe for ovarian cancer imaging

    NASA Astrophysics Data System (ADS)

    Salehi, Hassan S.; Kumavor, Patrick D.; Alqasemi, Umar; Li, Hai; Wang, Tianheng; Zhu, Quing

    2014-03-01

    A high-throughput ultrasound/photoacoustic probe for delivering high contrast and signal-to-noise ratio images was designed, constructed, and tested. The probe consists of a transvaginal ultrasound array integrated with four 1mm-core optical fibers and a sheath. The sheath encases transducer and is lined with highly reflecting aluminum for high intensity light output and uniformity while at the same time remaining below the maximum permissible exposure (MPE) recommended by the American National Standards Institute (ANSI). The probe design was optimized by simulating the light fluence distribution in Zemax. The performance of the probe was evaluated by experimental measurements of the fluence and real-time imaging of polyethylene-tubing filled with blood. These results suggest that our probe has great potential for in vivo imaging and characterization of ovarian cancer.

  7. Hoechst tagging: a modular strategy to design synthetic fluorescent probes for live-cell nucleus imaging.

    PubMed

    Nakamura, Akinobu; Takigawa, Kazumasa; Kurishita, Yasutaka; Kuwata, Keiko; Ishida, Manabu; Shimoda, Yasushi; Hamachi, Itaru; Tsukiji, Shinya

    2014-06-11

    We report a general strategy to create small-molecule fluorescent probes for the nucleus in living cells. Our strategy is based on the attachment of the DNA-binding Hoechst compound to a fluorophore of interest. Using this approach, simple fluorescein, BODIPY, and rhodamine dyes were readily converted to novel turn-on fluorescent nucleus-imaging probes.

  8. Development of a fiber based Raman probe compatible with interventional magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Ashok, Praveen C.; Praveen, Bavishna B.; Rube, Martin; Cox, Benjamin; Melzer, Andreas; Dholakia, Kishan

    2014-02-01

    Raman spectroscopy has proven to be a powerful tool for discriminating between normal and abnormal tissue types. Fiber based Raman probes have demonstrated its potential for in vivo disease diagnostics. Combining Raman spectroscopy with Magnetic Resonance Imaging (MRI) opens up new avenues for MR guided minimally invasive optical biopsy. Although Raman probes are commercially available, they are not compatible with a MRI environment due to the metallic components which are used to align the micro-optic components such as filters and lenses at the probe head. Additionally they are not mechanically compatible with a typical surgical environment as factors such as sterility and length of the probe are not addressed in those designs. We have developed an MRI compatible fiber Raman probe with a disposable probe head hence maintaining sterility. The probe head was specially designed to avoid any material that would cause MR imaging artefacts. The probe head that goes into patient's body had a diameter <1.5 mm so that it is compatible with biopsy needles and catheters. The probe has been tested in MR environment and has been proven to be capable of obtaining Raman signal while the probe is under real-time MR guidance.

  9. Imaging of oxygenation in 3D tissue models with multi-modal phosphorescent probes

    NASA Astrophysics Data System (ADS)

    Papkovsky, Dmitri B.; Dmitriev, Ruslan I.; Borisov, Sergei

    2015-03-01

    Cell-penetrating phosphorescence based probes allow real-time, high-resolution imaging of O2 concentration in respiring cells and 3D tissue models. We have developed a panel of such probes, small molecule and nanoparticle structures, which have different spectral characteristics, cell penetrating and tissue staining behavior. The probes are compatible with conventional live cell imaging platforms and can be used in different detection modalities, including ratiometric intensity and PLIM (Phosphorescence Lifetime IMaging) under one- or two-photon excitation. Analytical performance of these probes and utility of the O2 imaging method have been demonstrated with different types of samples: 2D cell cultures, multi-cellular spheroids from cancer cell lines and primary neurons, excised slices from mouse brain, colon and bladder tissue, and live animals. They are particularly useful for hypoxia research, ex-vivo studies of tissue physiology, cell metabolism, cancer, inflammation, and multiplexing with many conventional fluorophors and markers of cellular function.

  10. Synthesis of a Targeted Biarsenical Cy3-Cy5 Affinity Probe for Superresolution Fluorescence Imaging

    SciTech Connect

    Fu, Na; Xiong, Yijia; Squier, Thomas C.

    2012-11-01

    Photoswitchable fluorescent probes capable of the targeted labeling of tagged proteins are of significant interest due to their ability to enable in situ imaging of protein complexes within native biomolecular assemblies. Here we describe the synthesis of a fluorescent probe (AsCy3Cy5), and demonstrate the targeted labeling and super-resolution imaging of a tagged protein within a supramolecular protein complex.

  11. X-ray phase computed tomography for nanoparticulated imaging probes and therapeutics: preliminary feasibility study

    NASA Astrophysics Data System (ADS)

    Tang, Xiangyang; Yang, Yi; Tang, Shaojie

    2011-03-01

    With the scientific progress in cancer biology, pharmacology and biomedical engineering, the nano-biotechnology based imaging probes and therapeutical agents (namely probes/agents) - a form of theranostics - are among the strategic solutions bearing the hope for the cure of cancer. The key feature distinguishing the nanoparticulated probes/agents from their conventional counterparts is their targeting capability. A large surface-to-volume ratio in nanoparticulated probes/agents enables the accommodation of multiple targeting, imaging and therapeutic components to cope with the intra- and inter-tumor heterogeneity. Most nanoparticulated probes/agents are synthesized with low atomic number materials and thus their x-ray attenuation are very similar to biological tissues. However, their microscopic structures are very different, which may result in significant differences in their refractive properties. Recently, the investigation in the x-ray grating-based differential phase contrast (DPC) CT has demonstrated its advantages in differentiating low-atomic materials over the conventional attenuation-based CT. We believe that a synergy of x-ray grating-based DPC CT and nanoparticulated imaging probes and therapeutic agents may play a significant role in extensive preclinical and clinical applications, or even become a modality for molecular imaging. Hence, we propose to image the refractive property of nanoparticulated imaging probes and therapeutical agents using x-ray grating-based DPC CT. In this work, we conduct a preliminary feasibility study with a focus to characterize the contrast-to-noise ratio (CNR) and contrast-detail behavior of the x-ray grating-based DPC CT. The obtained data may be instructive to the architecture design and performance optimization of the x-ray grating-based DPC CT for imaging biomarker-targeted imaging probes and therapeutic agents, and even informative to the translation of preclinical research in theranostics into clinical applications.

  12. Disease-specific target gene expression profiling of molecular imaging probes: database development and clinical validation.

    PubMed

    Chan, Lawrence Wing-Chi; Ngo, Connie Hiu-Ching; Wang, Fengfeng; Zhao, Moss Y; Zhao, Mengying; Law, Helen Ka-Wai; Wong, Sze Chuen Cesar; Yung, Benjamin Yat-Ming

    2014-01-01

    Molecular imaging probes can target abnormal gene expression patterns in patients and allow early diagnosis of disease. For selecting a suitable imaging probe, the current Molecular Imaging and Contrast Agent Database (MICAD) provides descriptive and qualitative information on imaging probe characteristics and properties. However, MICAD does not support linkage with the expression profiles of target genes. The proposed Disease-specific Imaging Probe Profiling (DIPP) database quantitatively archives and presents the gene expression profiles of targets across different diseases, anatomic regions, and subcellular locations, providing an objective reference for selecting imaging probes. The DIPP database was validated with a clinical positron emission tomography (PET) study on lung cancer and an in vitro study on neuroendocrine cancer. The retrieved records show that choline kinase beta and glucose transporters were positively and significantly associated with lung cancer among the targets of 11C-choline and [18F]fluoro-2-deoxy-2-d-glucose (FDG), respectively. Their significant overexpressions corresponded to the findings that the uptake rate of FDG increased with tumor size but that of 11C-choline remained constant. Validated with the in vitro study, the expression profiles of disease-associated targets can indicate the eligibility of patients for clinical trials of the treatment probe. A Web search tool of the DIPP database is available at http://www.polyu.edu.hk/bmi/dipp/. PMID:25022454

  13. Fluoromodule-based reporter/probes designed for in vivo fluorescence imaging

    PubMed Central

    Zhang, Ming; Chakraborty, Subhasish K.; Sampath, Padma; Rojas, Juan J.; Hou, Weizhou; Saurabh, Saumya; Thorne, Steve H.; Bruchez, Marcel P.; Waggoner, Alan S.

    2015-01-01

    Optical imaging of whole, living animals has proven to be a powerful tool in multiple areas of preclinical research and has allowed noninvasive monitoring of immune responses, tumor and pathogen growth, and treatment responses in longitudinal studies. However, fluorescence-based studies in animals are challenging because tissue absorbs and autofluoresces strongly in the visible light spectrum. These optical properties drive development and use of fluorescent labels that absorb and emit at longer wavelengths. Here, we present a far-red absorbing fluoromodule–based reporter/probe system and show that this system can be used for imaging in living mice. The probe we developed is a fluorogenic dye called SC1 that is dark in solution but highly fluorescent when bound to its cognate reporter, Mars1. The reporter/probe complex, or fluoromodule, produced peak emission near 730 nm. Mars1 was able to bind a variety of structurally similar probes that differ in color and membrane permeability. We demonstrated that a tool kit of multiple probes can be used to label extracellular and intracellular reporter–tagged receptor pools with 2 colors. Imaging studies may benefit from this far-red excited reporter/probe system, which features tight coupling between probe fluorescence and reporter binding and offers the option of using an expandable family of fluorogenic probes with a single reporter gene. PMID:26348895

  14. Chemical-contrast imaging with pulse-shaping based pump-probe spectroscopy

    NASA Astrophysics Data System (ADS)

    Flynn, Daniel C.; Bhagwat, Amar R.; Ogilvie, Jennifer P.

    2013-02-01

    Ultrafast pump-probe spectroscopy and pulse-shaping techniques are providing new modes of contrast for the field of multiphoton microscopy. Endogenous species such as heme proteins show rich nonlinear spectroscopic signatures of excited state absorption, stimulated emission and ground-state bleaching. Commercially available octave-spanning Ti:sapphire oscillators offer new opportunities for imaging based on pump-probe contrast. Spatial light modulators take advantage of this large bandwidth, shaping pulses of light to selectively excite molecular structures with similar spectral properties. We present two-color pump-probe imaging of heme proteins solutions and red blood cells.

  15. An Ultrasensitive Cyclization-Based Fluorescent Probe for Imaging Native HOBr in Live Cells and Zebrafish.

    PubMed

    Xu, Kehua; Luan, Dongrui; Wang, Xiaoting; Hu, Bo; Liu, Xiaojun; Kong, Fanpeng; Tang, Bo

    2016-10-01

    Bromine has been reported recently as being the 28(th) essential element for human health. HOBr, which is generated in vivo from bromide, is a required factor in the formation of sulfilimine crosslinks in collagen IV. However, to date, no method for the specific detection of native HOBr in vivo has been reported. Herein, we develop a simple small molecular probe for imaging HOBr based on a specific cyclization catalyzed by HOBr. The probe can be easily synthesized in high yield through a Suzuki cross-coupling reaction. The probe exhibits ultrahigh sensitivity at the picomole level, in addition to specificity for HOBr and real-time response. Importantly, without Br(-) stimulation, this probe reports native HOBr levels in HepG2 cells. Thus, the probe is a promising new tool for imaging endogenous HOBr and may provide a means for finding new physiological functions of HOBr in living organisms. PMID:27629766

  16. Static and dynamic imaging of alveoli using optical coherence tomography needle probes.

    PubMed

    McLaughlin, Robert A; Yang, Xiaojie; Quirk, Bryden C; Lorenser, Dirk; Kirk, Rodney W; Noble, Peter B; Sampson, David D

    2012-09-01

    Imaging of alveoli in situ has for the most part been infeasible due to the high resolution required to discern individual alveoli and limited access to alveoli beneath the lung surface. In this study, we present a novel technique to image alveoli using optical coherence tomography (OCT). We propose the use of OCT needle probes, where the distal imaging probe has been miniaturized and encased within a hypodermic needle (as small as 30-gauge, outer diameter 310 μm), allowing insertion deep within the lung tissue with minimal tissue distortion. Such probes enable imaging at a resolution of ∼12 μm within a three-dimensional cylindrical field of view with diameter ∼1.5 mm centered on the needle tip. The imaging technique is demonstrated on excised lungs from three different species: adult rats, fetal sheep, and adult pigs. OCT needle probes were used to image alveoli, small bronchioles, and blood vessels, and results were matched to histological sections. We also present the first dynamic OCT images acquired with an OCT needle probe, allowing tracking of individual alveoli during simulated cyclical lung inflation and deflation. PMID:22773771

  17. Reversible two-photon fluorescent probe for imaging of hypochlorous acid in live cells and in vivo.

    PubMed

    Zhang, Wei; Liu, Wei; Li, Ping; kang, Junqing; Wang, Jiaoyang; Wang, Hui; Tang, Bo

    2015-06-25

    Herein, we have developed a novel reversible two-photon fluorescent probe that is well suited for monitoring HOCl levels selectively and instantaneously. Results showed the reversible and instantaneous responses of the probe towards intracellular HOCl. Moreover, the probe was successfully applied to the imaging of the HOCl levels in zebrafish and mice via two-photon imaging.

  18. Local collective motion analysis for multi-probe dynamic imaging and microrheology.

    PubMed

    Khan, Manas; Mason, Thomas G

    2016-08-01

    Dynamical artifacts, such as mechanical drift, advection, and hydrodynamic flow, can adversely affect multi-probe dynamic imaging and passive particle-tracking microrheology experiments. Alternatively, active driving by molecular motors can cause interesting non-Brownian motion of probes in local regions. Existing drift-correction techniques, which require large ensembles of probes or fast temporal sampling, are inadequate for handling complex spatio-temporal drifts and non-Brownian motion of localized domains containing relatively few probes. Here, we report an analytical method based on local collective motion (LCM) analysis of as few as two probes for detecting the presence of non-Brownian motion and for accurately eliminating it to reveal the underlying Brownian motion. By calculating an ensemble-average, time-dependent, LCM mean square displacement (MSD) of two or more localized probes and comparing this MSD to constituent single-probe MSDs, we can identify temporal regimes during which either thermal or athermal motion dominates. Single-probe motion, when referenced relative to the moving frame attached to the multi-probe LCM trajectory, provides a true Brownian MSD after scaling by an appropriate correction factor that depends on the number of probes used in LCM analysis. We show that LCM analysis can be used to correct many different dynamical artifacts, including spatially varying drifts, gradient flows, cell motion, time-dependent drift, and temporally varying oscillatory advection, thereby offering a significant improvement over existing approaches. PMID:27269299

  19. Local collective motion analysis for multi-probe dynamic imaging and microrheology

    NASA Astrophysics Data System (ADS)

    Khan, Manas; Mason, Thomas G.

    2016-08-01

    Dynamical artifacts, such as mechanical drift, advection, and hydrodynamic flow, can adversely affect multi-probe dynamic imaging and passive particle-tracking microrheology experiments. Alternatively, active driving by molecular motors can cause interesting non-Brownian motion of probes in local regions. Existing drift-correction techniques, which require large ensembles of probes or fast temporal sampling, are inadequate for handling complex spatio-temporal drifts and non-Brownian motion of localized domains containing relatively few probes. Here, we report an analytical method based on local collective motion (LCM) analysis of as few as two probes for detecting the presence of non-Brownian motion and for accurately eliminating it to reveal the underlying Brownian motion. By calculating an ensemble-average, time-dependent, LCM mean square displacement (MSD) of two or more localized probes and comparing this MSD to constituent single-probe MSDs, we can identify temporal regimes during which either thermal or athermal motion dominates. Single-probe motion, when referenced relative to the moving frame attached to the multi-probe LCM trajectory, provides a true Brownian MSD after scaling by an appropriate correction factor that depends on the number of probes used in LCM analysis. We show that LCM analysis can be used to correct many different dynamical artifacts, including spatially varying drifts, gradient flows, cell motion, time-dependent drift, and temporally varying oscillatory advection, thereby offering a significant improvement over existing approaches.

  20. Imaging viral RNA using multiply labeled tetravalent RNA imaging probes in live cells.

    PubMed

    Alonas, Eric; Vanover, Daryll; Blanchard, Emmeline; Zurla, Chiara; Santangelo, Philip J

    2016-04-01

    Viruses represent an important class of pathogens that have had an enormous impact on the health of the human race. They are extraordinarily diverse; viral particles can range in size from ∼80nm to ∼10μm in length, and contain genomes with RNA or DNA strands. Regardless of their genome type, RNA species are frequently generated as a part of their replication process, and for viruses with RNA genomes, their loading into the virion represents a critical step in the creation of infectious particles. RNA imaging tools represent a powerful approach to gain insight into fundamental viral processes, including virus entry, replication, and virion assembly. Imaging viral processes in live cells is critical due to both the heterogeneity of these processes on a per cell basis, and the inherent dynamics of these processes. There are a number of methods for labeling RNA in live cells; we'll introduce the myriad of methods and then focus on one approach for labeling viral RNA, using multiply-labeled tetravalent RNA imaging probes (MTRIPs), which do not require engineering of the target RNAs. We feel this approach is advantageous given many viral genomes may not tolerate large nucleotide insertions into their sequences. PMID:26875782

  1. Enhanced Fluorescence Imaging of Live Cells by Effective Cytosolic Delivery of Probes

    PubMed Central

    Massignani, Marzia; Canton, Irene; Sun, Tao; Hearnden, Vanessa; MacNeil, Sheila; Blanazs, Adam; Armes, Steven P.; Lewis, Andrew; Battaglia, Giuseppe

    2010-01-01

    Background Microscopic techniques enable real-space imaging of complex biological events and processes. They have become an essential tool to confirm and complement hypotheses made by biomedical scientists and also allow the re-examination of existing models, hence influencing future investigations. Particularly imaging live cells is crucial for an improved understanding of dynamic biological processes, however hitherto live cell imaging has been limited by the necessity to introduce probes within a cell without altering its physiological and structural integrity. We demonstrate herein that this hurdle can be overcome by effective cytosolic delivery. Principal Findings We show the delivery within several types of mammalian cells using nanometre-sized biomimetic polymer vesicles (a.k.a. polymersomes) that offer both highly efficient cellular uptake and endolysomal escape capability without any effect on the cellular metabolic activity. Such biocompatible polymersomes can encapsulate various types of probes including cell membrane probes and nucleic acid probes as well as labelled nucleic acids, antibodies and quantum dots. Significance We show the delivery of sufficient quantities of probes to the cytosol, allowing sustained functional imaging of live cells over time periods of days to weeks. Finally the combination of such effective staining with three-dimensional imaging by confocal laser scanning microscopy allows cell imaging in complex three-dimensional environments under both mono-culture and co-culture conditions. Thus cell migration and proliferation can be studied in models that are much closer to the in vivo situation. PMID:20454666

  2. Near-infrared fluorescent probes in cancer imaging and therapy: an emerging field

    PubMed Central

    Yi, Xiaomin; Wang, Fuli; Qin, Weijun; Yang, Xiaojian; Yuan, Jianlin

    2014-01-01

    Near-infrared fluorescence (NIRF) imaging is an attractive modality for early cancer detection with high sensitivity and multi-detection capability. Due to convenient modification by conjugating with moieties of interests, NIRF probes are ideal candidates for cancer targeted imaging. Additionally, the combinatory application of NIRF imaging and other imaging modalities that can delineate anatomical structures extends fluorometric determination of biomedical information. Moreover, nanoparticles loaded with NIRF dyes and anticancer agents contribute to the synergistic management of cancer, which integrates the advantage of imaging and therapeutic functions to achieve the ultimate goal of simultaneous diagnosis and treatment. Appropriate probe design with targeting moieties can retain the original properties of NIRF and pharmacokinetics. In recent years, great efforts have been made to develop new NIRF probes with better photostability and strong fluorescence emission, leading to the discovery of numerous novel NIRF probes with fine photophysical properties. Some of these probes exhibit tumoricidal activities upon light radiation, which holds great promise in photothermal therapy, photodynamic therapy, and photoimmunotherapy. This review aims to provide a timely and concise update on emerging NIRF dyes and multifunctional agents. Their potential uses as agents for cancer specific imaging, lymph node mapping, and therapeutics are included. Recent advances of NIRF dyes in clinical use are also summarized. PMID:24648733

  3. Methods for providing probe position and temperature information on MR images during interventional procedures.

    PubMed

    Patel, K C; Duerk, J L; Zhang, Q; Chung, Y C; Williams, M; Kaczynski, K; Wendt, M; Lewin, J S

    1998-10-01

    Interventional magnetic resonance imaging (MRI) can be defined as the use of MR images for guiding and monitoring interventional procedures (e.g., biopsy, drainage) or minimally invasive therapy (e.g., thermal ablation). This work describes the development of a prototype graphical user interface and the appropriate software methods to accurately overlay a representation of a rigid interventional device [e.g., biopsy needle, radio-frequency (RF) probe] onto an MR image given only the probe's spatial position and orientation as determined from a three-dimensional (3-D) localizer used for interactive scan plane definition. This permits 1) "virtual tip tracking," where the probe tip location is displayed on the image without the use of separate receiver coils or a "road map" image data set, and, 2) "extending" the probe to predict its path if it were directly moved forward toward the target tissue. Further, this paper describes the design and implementation of a method to facilitate the monitoring of thermal ablation procedures by displaying and overlaying temperature maps from temperature sensitive MR acquisitions. These methods provide rapid graphical updates of probe position and temperature changes to aid the physician during the actual interventional MRI procedures without altering the usual operation of the MR imager. PMID:9874304

  4. High speed miniature motorized endoscopic probe for 3D optical frequency domain imaging

    NASA Astrophysics Data System (ADS)

    Li, Jianan; Feroldi, Fabio; Mo, Jianhua; Helderman, Frank; de Groot, Mattijs; de Boer, Johannes F.

    2013-03-01

    We present a miniature motorized endoscopic probe for Optical Frequency Domain Imaging with an outer diameter of 1.65 mm and a rotation speed of 3,000 - 12,500 rpm. This is the smallest motorized high speed OCT probe to our knowledge. The probe has a motorized distal end which provides a significant advantage over proximally driven probes since it does not require a drive shaft to transfer the rotational torque to the distal end of the probe and functions without a fiber rotary junction. The probe has a focal Full Width at Half Maximum of 9.6 μm and a working distance of 0.47 mm. We analyzed the non-uniform rotation distortion and found a location fluctuation of only 1.87° in repeated measurements of the same object. The probe was integrated in a high-speed Optical Frequency Domain Imaging setup at 1310 nm We demonstrated its performance with imaging ex vivo pig bronchial and in vivo goat lung.

  5. Genetically Anchored Fluorescent Probes for Subcellular Specific Imaging of Hydrogen Sulfide

    PubMed Central

    Jiang, Xiqian; Sizovs, Antons; Wang, Meng C.; Provost, Christopher R.; Huang, Jia

    2016-01-01

    Imaging hydrogen sulfide (H2S) at the subcellular resolution will greatly improve the understanding of functions of this signaling molecule. Taking advantage of the protein labeling technologies, we report a general strategy for the development of organelle specific H2S probes, which enables sub-cellular H2S imaging essentially in any organelles of interest. PMID:26806071

  6. NEAR-INFRARED DYES: Probe Development and Applications in Optical Molecular Imaging

    PubMed Central

    Nolting, Donald D.; Gore, John C.; Pham, Wellington

    2010-01-01

    The recent emergence of optical imaging has brought forth a unique challenge for chemists: development of new biocompatible dyes that fluoresce in the near-infrared (NIR) region for optimal use in biomedical applications. This review describes the synthesis of NIR dyes and the design of probes capable of noninvasively imaging molecular events in small animal models. PMID:21822405

  7. Brightness enhanced DNA FIT-probes for wash-free RNA imaging in tissue.

    PubMed

    Hövelmann, Felix; Gaspar, Imre; Ephrussi, Anne; Seitz, Oliver

    2013-12-18

    Fluorogenic oligonucleotides enable RNA imaging in cells and tissues. A high responsiveness of fluorescence is required when unbound probes cannot be washed away. Furthermore, emission should be bright in order to enable detection against autofluorescent background. The development of fluorescence-quenched hybridization probes has led to remarkable improvement of fluorescence responsiveness. Yet, comparably little attention has been paid to the brightness of smart probes. We describe hybridization probes that combine responsiveness with a high brightness of the measured signal. The method relies upon quencher-free DNA forced intercalation (FIT)-probes, in which two (or more) intercalator dyes of the thiazole orange (TO) family serve as nucleobase surrogates. Initial experiments on multi-TO-labeled probes led to improvements of responsiveness, but self-quenching limited their brightness. To enhance both brightness and responsiveness the highly responsive TO nucleoside was combined with the highly emissive oxazolopyridine analogue JO. Single-stranded TO/JO FIT-probes are dark. In the probe-target duplex, quenching caused by torsional twisting and dye-dye contact is prevented. The TO nucleoside appears to serve as a light collector that increases the extinction coefficient and transfers excitation energy to the JO emitter. This leads to very bright JO emission upon hybridization (F/F0 = 23, brightness = 43 mL mol(-1) cm(-1) at λex = 516 nm). TO/JO FIT-probes allowed the direct fluorescence microscopic imaging of oskar mRNA within a complex tissue. Of note, RNA imaging was feasible under wide-field excitation conditions. The described protocol enables rapid RNA imaging in tissue without the need for cutting-edge equipment, time-consuming washing, or signal amplification.

  8. Semiconducting Polymer Nanoparticles as Photoacoustic Molecular Imaging Probes in Living Mice

    PubMed Central

    Pu, Kanyi; Shuhendler, Adam J.; Jokerst, Jesse V.; Mei, Jianguo; Gambhir, Sanjiv S.; Bao, Zhenan; Rao, Jianghong

    2014-01-01

    Photoacoustic (PA) imaging holds great promise for the visualization of physiology and pathology at the molecular level with deep tissue penetration and fine spatial resolution. To fully utilize this potential, PA molecular imaging probes have to be developed. Herein we introduce near infrared (NIR) light absorbing semiconducting polymer nanoparticles (SPNs) as a new class of contrast agents for PA molecular imaging. SPNs can produce stronger signal than commonly used single-wall carbon nanotubes and gold nanorods on a per mass basis, permitting whole-body lymph node PA mapping in living mice at a low systematic injection mass. Furthermore, SPNs possess high structural flexibility, narrow PA spectral profiles, and strong resistance to photodegradation and oxidation, which enables development of the first NIR ratiometric PA probe for in vivo real-time imaging of reactive oxygen species—vital chemical mediators of many diseases. These results demonstrate SPNs an ideal nanoplatform for developing PA molecular probes. PMID:24463363

  9. Convergent synthesis and evaluation of 18F-labeled azulenic COX2 probes for cancer imaging

    PubMed Central

    Nolting, Donald D.; Nickels, Michael; Tantawy, Mohammed N.; Yu, James Y. H.; Xie, Jingping; Peterson, Todd E.; Crews, Brenda C.; Marnett, Larry; Gore, John C.; Pham, Wellington

    2013-01-01

    The overall objectives of this research are to (i) develop azulene-based positron emission tomography (PET) probes and (ii) image COX2 as a potential biomarker of breast cancer. Several lines of research have demonstrated that COX2 is overexpressed in breast cancer and that its presence correlates with poor prognoses. While other studies have reported that COX2 inhibition can be modulated and used beneficially as a chemopreventive strategy in cancer, no viable mechanism for achieving that approach has yet been developed. This shortfall could be circumvented through in vivo imaging of COX2 activity, particularly using sensitive imaging techniques such as PET. Toward that goal, our laboratory focuses on the development of novel 18F-labled COX2 probes. We began the synthesis of the probes by transforming tropolone into a lactone, which was subjected to an [8 + 2] cycloaddition reaction to yield 2-methylazulene as the core ring of the probe. After exploring numerous synthetic routes, the final target molecule and precursor PET compounds were prepared successfully using convergent synthesis. Conventional 18F labeling methods caused precursor decomposition, which prompted us to hypothesize that the acidic protons of the methylene moiety between the azulene and thiazole rings were readily abstracted by a strong base such as potassium carbonate. Ultimately, this caused the precursors to disintegrate. This observation was supported after successfully using an 18F labeling strategy that employed a much milder phosphate buffer. The 18F-labeled COX2 probe was tested in a breast cancer xenograft mouse model. The data obtained via successive whole-body PET/CT scans indicated probe accumulation and retention in the tumor. Overall, the probe was stable in vivo and no defluorination was observed. A biodistribution study and Western blot analysis corroborate with the imaging data. In conclusion, this novel COX2 PET probe was shown to be a promising agent for cancer imaging and

  10. Water-soluble BODIPY-based fluorescent probe for mitochondrial imaging (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Sui, Binglin; Tang, Simon; Woodward, Adam W.; Kim, Bosung; Belfield, Kevin D.

    2016-03-01

    A new mitochondrial targeting fluorescent probe is designed, synthesized, characterized, and investigated. The probe is composed of three moieties, a BODIPY platform working as the fluorophore, two triphenylphosphonium (TPP) groups serving as mitochondrial targeting moiety, and two long highly hydrophilic polyethylene glycol (PEG) chains to increase its water solubility and reduce its cytotoxicity. As a mitochondria-selective fluorescent probe, the probe exhibits a series of desirable advantages compared with other reported fluorescent mitochondrial probes. It is readily soluble in aqueous media and emits very strong fluorescence. Photophysical determination experiments show that the photophysical properties of the probe are independent of solvent polarity and it has high quantum yield in various solvents examined. The probe also has good photostability and pH insensitivity over a broad pH range. Results obtained from cell viability tests indicate that the cytotoxicity of the probe is very low. Confocal fluorescence microscopy colocalization experiments reveal that this probe possesses excellent mitochondrial targeting ability and it is suitable for imaging mitochondria in living cells.

  11. Electromechanical Imaging of Biomaterials by Scanning Probe Microscopy

    SciTech Connect

    Rodriguez, Brian J; Kalinin, Sergei V; Shin, Junsoo; Jesse, Stephen; Grichko, V.; Thundat, Thomas George; Baddorf, Arthur P; Gruverman, A.

    2006-01-01

    The majority of calcified and connective tissues possess complex hierarchical structure spanning the length scales from nanometers to millimeters. Understanding the biological functionality of these materials requires reliable methods for structural imaging on the nanoscale. Here, we demonstrate an approach for electromechanical imaging of the structure of biological samples on the length scales from tens of microns to nanometers using piezoresponse force microscopy (PFM), which utilizes the intrinsic piezoelectricity of biopolymers such as proteins and polysaccharides as the basis for high-resolution imaging. Nanostructural imaging of a variety of protein-based materials, including tooth, antler, and cartilage, is demonstrated. Visualization of protein fibrils with sub-10 nm spatial resolution in a human tooth is achieved. Given the near-ubiquitous presence of piezoelectricity in biological systems, PFM is suggested as a versatile tool for micro- and nanostructural imaging in both connective and calcified tissues.

  12. Study on the SPR responses of various DNA probe concentrations by parallel scan spectral SPR imaging

    NASA Astrophysics Data System (ADS)

    Ma, Suihua; Liu, Le; Lu, Weiping; Zhang, Yaou; He, Yonghong; Guo, Jihua

    2008-12-01

    SPR sensors have become a high sensitive and label free method for characterizing and quantifying chemical and biochemical interactions. However, the relations between the SPR refractive index response and the property (such as concentrations) of biochemical probes are still lacking. In this paper, an experimental study on the SPR responses of varies concentrations of Legionella pneumophila mip DNA probes is presented. We developed a novel two-dimensional SPR sensing technique-parallel scan spectral SPR imaging-to detect an array of mip gene probes. This technique offers quantitative refractive index information with a high sensing throughput. By detecting mip DNA probes with different concentrations, we obtained the relations between the SPR refractive index response and the concentrations of mip DNA probes. These results are valuable for design and developing SPR based mip gene biochips.

  13. A fluorogenic probe for β-galactosidase activity imaging in living cells.

    PubMed

    Han, Junyan; Han, Myung Shin; Tung, Ching-Hsuan

    2013-12-01

    A cell permeable fluorescence turn-on probe, AcGQCy7, was developed to image β-galactosidase activity in living cells. Once internalized by β-galactosidase-expressing cells, the probe was hydrolyzed into a highly fluorescent molecule, and the fluorescent signal was retained in mitochondria for several days. This resulted in a long-lasting and strong β-galactosidase-dependent intracellular fluorescent signal with little background fluorescence in the culture media.

  14. Integrated flexible handheld probe for imaging and evaluation of iridocorneal angle

    NASA Astrophysics Data System (ADS)

    Shinoj, Vengalathunadakal K.; Murukeshan, Vadakke Matham; Baskaran, Mani; Aung, Tin

    2015-01-01

    An imaging probe is designed and developed by integrating a miniaturized charge-coupled diode camera and light-emitting diode light source, which enables evaluation of the iridocorneal region inside the eye. The efficiency of the prototype probe instrument is illustrated initially by using not only eye models, but also samples such as pig eye. The proposed methodology and developed scheme are expected to find potential application in iridocorneal angle documentation, glaucoma diagnosis, and follow-up management procedures.

  15. Asteroid (4179) Toutatis size determination via optical images observed by the Chang'e-2 probe

    NASA Astrophysics Data System (ADS)

    Liu, P.; Huang, J.; Zhao, W.; Wang, X.; Meng, L.; Tang, X.

    2014-07-01

    This work is a physical and statistical study of the asteroid (4179) Toutatis using the optical images obtained by a solar panel monitor of the Chang'e-2 probe on Dec. 13, 2012 [1]. In the imaging strategy, the camera is focused at infinity. This is specially designed for the probe with its solar panels monitor's principle axis pointing to the relative velocity direction of the probe and Toutatis. The imaging strategy provides a dedicated way to resolve the size by multi-frame optical images. The inherent features of the data are: (1) almost no rotation was recorded because of the 5.41-7.35 Earth-day rotation period and the small amount of elapsed imaging time, only minutes, make the object stay in the images in a fixed position and orientation; (2) the sharpness of the upper left boundary and the vagueness of lower right boundary resulting from the direction of SAP (Sun-Asteroid-Probe angle) cause a varying accuracy in locating points at different parts of Toutatis. A common view is that direct, accurate measurements of asteroid shapes, sizes, and pole positions are now possible for larger asteroids that can be spatially resolved using the Hubble Space Telescope or large ground-based telescopes equipped with adaptive optics. For a quite complex planetary/asteroid probe study, these measurements certainly need continuous validation via a variety of ways [2]. Based on engineering parameters of the probe during the fly-by, the target spatial resolving and measuring procedures are described in the paper. Results estimated are optical perceptible size on the flyby epoch under the solar phase angles during the imaging. It is found that the perceptible size measured using the optical observations and the size derived from the radar observations by Ostro et al.~in 1995 [3], are close to one another.

  16. Dual-illumination mode, wide-field probe imaging scheme for imaging irido-corneal angle region inside eye

    NASA Astrophysics Data System (ADS)

    Shinoj, V. K.; Murukeshan, V. M.; Hong, Jesmond; Baskaran, M.; Aung, Tin

    2015-07-01

    Noninvasive medical imaging techniques have generated great interest and high potential in the research and development of ocular imaging and follow up procedures. It is well known that angle closure glaucoma is one of the major ocular diseases/ conditions that causes blindness. The identification and treatment of this disease are related primarily to angle assessment techniques. In this paper, we illustrate a probe-based imaging approach to obtain the images of the angle region in eye. The proposed probe consists of a micro CCD camera and LED/NIR laser light sources and they are configured at the distal end to enable imaging of iridocorneal region inside eye. With this proposed dualmodal probe, imaging is performed in light (white visible LED ON) and dark (NIR laser light source alone) conditions and the angle region is noticeable in both cases. The imaging using NIR sources have major significance in anterior chamber imaging since it evades pupil constriction due to the bright light and thereby the artificial altering of anterior chamber angle. The proposed methodology and developed scheme are expected to find potential application in glaucoma disease detection and diagnosis.

  17. Molecular probes for imaging of hypoxia in the retina.

    PubMed

    Evans, Stephanie M; Kim, Kwangho; Moore, Chauca E; Uddin, Md Imam; Capozzi, Megan E; Craft, Jason R; Sulikowski, Gary A; Jayagopal, Ashwath

    2014-11-19

    Hypoxia has been associated with retinal diseases which lead the causes of irreversible vision loss, including diabetic retinopathy, retinopathy of prematurity, and age-related macular degeneration. Therefore, technologies for imaging hypoxia in the retina are needed for early disease detection, monitoring of disease progression, and assessment of therapeutic responses in the patient. Toward this goal, we developed two hypoxia-sensitive imaging agents based on nitroimidazoles which are capable of accumulating in hypoxic cells in vivo. 2-nitroimidazole or Pimonidazole was conjugated to fluorescent dyes to yield the imaging agents HYPOX-1 and HYPOX-2. Imaging agents were characterized in cell culture and animal models of retinal vascular diseases which exhibit hypoxia. Both HYPOX-1 and -2 were capable of detecting hypoxia in cell culture models with >10:1 signal-to-noise ratios without acute toxicity. Furthermore, intraocular administration of contrast agents in mouse models of retinal hypoxia enabled ex vivo detection of hypoxic tissue. These imaging agents are a promising step toward translation of hypoxia-sensitive molecular imaging agents in preclinical animal models and patients.

  18. Extracellularly activatable nanocarriers for drug delivery to tumors

    PubMed Central

    Yeo, Yoon

    2014-01-01

    Introduction Nanoparticles for drug delivery to tumors need to satisfy two seemingly conflicting requirements: they should maintain physical and chemical stability during circulation and be able to interact with target cells and release drug at desired locations with no substantial delay. Unique microenvironment of tumors and externally-applied stimuli provide a useful means to maintain a balance between the two requirements. Areas covered We discuss nanoparticulate drug carriers that maintain stable structures in normal conditions but respond to stimuli for spatiotemporal control of drug delivery. We first define the desired effects of extracellular activation of nanoparticles and frequently used stimuli and review examples of extracellularly activated nanoparticles. Expert opinion Several challenges remain in developing extracellularly activatable nanoparticles. First, some of the stimuli-responsive NPs undergo incremental changes in response to stimuli, losing circulation stability. Second, the applicability of stimuli in clinical settings is limited due to the occasional occurrence of the activating conditions in normal tissues. Third, the construction of stimuli-responsive nanoparticles involves increasing complexity in nanoparticle structure and production methods. Future efforts are needed to identify new targeting conditions and increase the contrast between activated and non-activated NPs, while keeping the production methods simple and scalable. PMID:24950343

  19. Amyloid-β Positron Emission Tomography Imaging Probes: A Critical Review

    PubMed Central

    Kepe, Vladimir; Moghbel, Mateen C.; Långström, Bengt; Zaidi, Habib; Vinters, Harry V.; Huang, Sung-Cheng; Satyamurthy, Nagichettiar; Doudet, Doris; Mishani, Eyal; Cohen, Robert M.; Høilund-Carlsen, Poul F.; Alavi, Abass; Barrio, Jorge R.

    2013-01-01

    The rapidly rising prevalence and cost of Alzheimer’s disease (AD) in recent decades has made the imaging of amyloid-β (Aβ) deposits the focus of intense research. Several amyloid imaging probes with purported specificity for Aβ plaques are currently at various stages of FDA approval. However, a number of factors appear to preclude these probes from clinical utilization. As the available “amyloid specific” PET imaging probes have failed to demonstrate diagnostic value and have shown limited utility for monitoring therapeutic interventions in humans, a debate on their significance has emerged. The aim of this review is to identify and discuss critically the scientific issues contributing to the extensive inconsistencies reported in the literature on their purported in vivo amyloid specificity and potential utilization in patients. PMID:23648516

  20. Ultrafast nanoscale imaging of surface charges by scanning resistive probe microscopy.

    SciTech Connect

    Ko, H.; Ryu, K.; Park, H.; Park, C.; Jeon, D.; Kim, Y. K.; Jung, J.; Min, D-K.; Kim, Y.; Lee, H. N.; Park, Y.; Shin, H.; Hong, S.

    2011-01-01

    Nanoscale manipulation of surface charges and their imaging are essential for understanding local electronic behaviors of polar materials and advanced electronic devices. Electrostatic force microscopy and Kelvin probe force microscopy have been extensively used to probe and image local surface charges responsible for electrodynamics and transport phenomena. However, they rely on the weak electric force modulation of cantilever that limits both spatial and temporal resolutions. Here we present a field effect transistor embedded probe that can directly image surface charges on a length scale of 25 nm and a time scale of less than 125 {mu}s. On the basis of the calculation of net surface charges in a 25 nm diameter ferroelectric domain, we could estimate the charge density resolution to be as low as 0.08 {mu}C/cm{sup 2}, which is equivalent to 1/20 electron per nanometer square at room temperature.

  1. Novel PET/SPECT Probes for Imaging of Tau in Alzheimer's Disease

    PubMed Central

    Ono, Masahiro

    2015-01-01

    As the world's population ages, the number of patients with Alzheimer's disease (AD) is predicted to increase rapidly. The presence of neurofibrillary tangles (NFTs), composed of hyperphosphorylated tau protein, is one of the neuropathological hallmarks of AD brain. Since the presence of NFTs is well correlated with neurodegeneration and cognitive decline in AD, imaging of tau using positron emission tomography (PET) and single-photon emission computed tomography (SPECT) is useful for presymptomatic diagnosis and monitoring of the progression of AD. Therefore, novel PET/SPECT probes for the imaging of tau have been developed. More recently, several probes were tested clinically and evaluated for their utility. This paper reviews the current state of research on the development and evaluation of PET/SPECT probes for the imaging of tau in AD brain. PMID:25879047

  2. A Bridge Not Too Far: Linking Disciplines Through Molecular Imaging Probes.

    PubMed

    Valliant, John F

    2016-09-01

    The field of nuclear medicine will rely increasingly on the discovery, proper evaluation, and clinical use of molecular imaging probes and on collaborations. Collaborations will include new initiatives among experts already involved in the field and with researchers, technologists, and clinicians from different areas of science and medicine. This article serves to highlight some of the opportunities in which molecular imaging and nuclear medicine in conjunction with probe development, new imaging technologies, and multidisciplinary collaborations can have a significant impact on health care and basic science from the perspective of a person involved in probe development. The article emphasizes breast cancer, but the concepts are readily applied to other areas of medicine and medical research. PMID:27601414

  3. Ratiometric and near-infrared molecular probes for the detection and imaging of zinc ions.

    PubMed

    Carol, Priya; Sreejith, Sivaramapanicker; Ajayaghosh, Ayyappanpillai

    2007-03-01

    The detection and imaging of Zn2+ in biological samples are of paramount interest owing to the role of this cation in physiological functions. This is possible only with molecular probes that specifically bind to Zn2+ and result in changes in emission properties. A "turn-on" emission or shift in the emission color upon binding to Zn2+ should be ideal for in vivo imaging. In this context, ratiometric and near-IR probes are of particular interest. Therefore, in the area of chemosensors or molecular probes, the design of fluorophores that allow ratiometric sensing or imaging in the near-IR region is attracting the attention of chemists. The purpose of this Focus Review is to highlight recent developments in this area and stress the importance of further research for future applications.

  4. Novel Bioluminescent Activatable Reporter for Src Tyrosine Kinase Activity in Living Mice

    PubMed Central

    Leng, Weibing; Li, Dezhi; Chen, Liang; Xia, Hongwei; Tang, Qiulin; Chen, Baoqin; Gong, Qiyong; Gao, Fabao; Bi, Feng

    2016-01-01

    Aberrant activation of the Src kinase is implicated in the development of a variety of human malignancies. However, it is almost impossible to monitor Src activity in an in vivo setting with current biochemical techniques. To facilitate the noninvasive investigation of the activity of Src kinase both in vitro and in vivo, we developed a genetically engineered, activatable bioluminescent reporter using split-luciferase complementation. The bioluminescence of this reporter can be used as a surrogate for Src activity in real time. This hybrid luciferase reporter was constructed by sandwiching a Src-dependent conformationally responsive unit (SH2 domain-Srcpep) between the split luciferase fragments. The complementation bioluminescence of this reporter was dependent on the Src activity status. In our study, Src kinase activity in cultured cells and tumor xenografts was monitored quantitatively and dynamically in response to clinical small-molecular kinase inhibitors, dasatinib and saracatinib. This system was also applied for high-throughput screening of Src inhibitors against a kinase inhibitor library in living cells. These results provide unique insights into drug development and pharmacokinetics/phoarmocodynamics of therapeutic drugs targeting Src signaling pathway enabling the optimization of drug administration schedules for maximum benefit. Using both Firefly and Renilla luciferase imaging, we have successfully monitored Src tyrosine kinase activity and Akt serine/threonine kinase activity concurrently in one tumor xenograft. This dual luciferase reporter imaging system will be helpful in exploring the complex signaling networks in vivo. The strategies reported here can also be extended to study and image other important kinases and the cross-talks among them. PMID:26941850

  5. Novel Bioluminescent Activatable Reporter for Src Tyrosine Kinase Activity in Living Mice.

    PubMed

    Leng, Weibing; Li, Dezhi; Chen, Liang; Xia, Hongwei; Tang, Qiulin; Chen, Baoqin; Gong, Qiyong; Gao, Fabao; Bi, Feng

    2016-01-01

    Aberrant activation of the Src kinase is implicated in the development of a variety of human malignancies. However, it is almost impossible to monitor Src activity in an in vivo setting with current biochemical techniques. To facilitate the noninvasive investigation of the activity of Src kinase both in vitro and in vivo, we developed a genetically engineered, activatable bioluminescent reporter using split-luciferase complementation. The bioluminescence of this reporter can be used as a surrogate for Src activity in real time. This hybrid luciferase reporter was constructed by sandwiching a Src-dependent conformationally responsive unit (SH2 domain-Srcpep) between the split luciferase fragments. The complementation bioluminescence of this reporter was dependent on the Src activity status. In our study, Src kinase activity in cultured cells and tumor xenografts was monitored quantitatively and dynamically in response to clinical small-molecular kinase inhibitors, dasatinib and saracatinib. This system was also applied for high-throughput screening of Src inhibitors against a kinase inhibitor library in living cells. These results provide unique insights into drug development and pharmacokinetics/phoarmocodynamics of therapeutic drugs targeting Src signaling pathway enabling the optimization of drug administration schedules for maximum benefit. Using both Firefly and Renilla luciferase imaging, we have successfully monitored Src tyrosine kinase activity and Akt serine/threonine kinase activity concurrently in one tumor xenograft. This dual luciferase reporter imaging system will be helpful in exploring the complex signaling networks in vivo. The strategies reported here can also be extended to study and image other important kinases and the cross-talks among them. PMID:26941850

  6. A targeted molecular probe for colorectal cancer imaging

    NASA Astrophysics Data System (ADS)

    Attramadal, T.; Bjerke, R.; Indrevoll, B.; Moestue, S.; Rogstad, A.; Bendiksen, R.; Healey, A.; Johannesen, E.

    2008-02-01

    Colorectal cancer is a major cause of cancer death. Morbidity, mortality and healthcare costs can be reduced if the disease can be detected at an early stage. Screening is a viable approach as there is a clear link to risk factors such as age. We have developed a fluorescent contrast agent for use during colonoscopy. The agent is administered intravenously and is targeted to an early stage molecular marker for colorectal cancer. The agent consists of a targeting section comprising a peptide, and a fluorescent reporter molecule. Clinical imaging of the agent is to be performed with a far red fluorescence imaging channel (635 nm excitation/660-700 nm emission) as an adjunct to white light colonoscopy. Preclinical proof of mechanism results are presented. The compound has a K d of ~3nM. Two human xenograft tumour models were used. Tumour cells were implanted and grown subcutaneously in nude mice. Imaging using a fluorescence reflectance imaging system and quantitative biodistribution studies were performed. Substances tested include the targeted agent, and a scrambled sequence of the peptide (no binding) used as a negative control. Competition studies were also performed by co-administration of 180 times excess unlabelled peptide. Positive imaging contrast was shown in the tumours, with a clear relationship to expression levels (confirmed with quantitative biodistribution data). There was a significant difference between the positive and negative control substances, and a significant reduction in contrast in the competition experiment.

  7. Protein nanospheres: synergistic nanoplatform-based probes for multimodality imaging

    NASA Astrophysics Data System (ADS)

    McDonald, Michael A.; Wang, Paul C.; Siegel, Eliot L.

    2011-03-01

    No single clinical imaging modality has the ability to provide both high resolution and high sensitivity at the anatomical, functional and molecular level. Synergistically integrated detection techniques overcome these barriers by combining the advantages of different imaging modalities while reducing their disadvantages. We report the development of protein nanospheres optimized for enhancing MRI, CT and US contrast while also providing high sensitivity optical detection. Transferrin protein nanospheres (TfpNS), silicon coated, doped rare earth oxide and rhodamine B isothiocyanate nanoparticles, Si⊂Gd2O3:Eu,RBITC, (NP) and transferrin protein nanospheres encapsulating Si⊂Gd2O3:Eu,RBITC nanoparticles (TfpNS-NP) were prepared in tissue-mimicking phantoms and imaged utilizing multiple cross-sectional imaging modalities. Preliminary results indicate a 1:1 NP to TfpNS ratio in TfpNS-NP and improved sensitivity of detection for MRI, CT, US and fluorescence imaging relative to its component parts and/or many commercially available contrast agents.

  8. Imaging Microscopic Pigment Chemistry in Conjunctival Melanocytic Lesions Using Pump-Probe Laser Microscopy

    PubMed Central

    Wilson, Jesse W.; Vajzovic, Lejla; Robles, Francisco E.; Cummings, Thomas J.; Mruthyunjaya, Prithvi; Warren, Warren S.

    2013-01-01

    Purpose. To report the application of a novel imaging technique, pump-probe microscopy, to analyze patterns of pigment chemistry of conjunctival melanocytic lesion biopsies. Methods. Histopathologic specimens of eight previously excised conjunctival melanocytic lesions were analyzed with pump-probe microscopy. The technique uses a laser scanning microscope with a two-color pulsed laser source to distinguish hemoglobin, eumelanin, and pheomelanin pigment based on differences in transient excited state and ground state photodynamics. The pump-probe signatures of conjunctival melanins were compared with cutaneous melanins. The distributions of hemoglobin, eumelanin, and pheomelanin were analyzed, and pump-probe images were correlated with adjacent hematoxylin and eosin (H&E)-stained sections. Results. The pump-probe signatures of conjunctival melanins are similar, but not identical to cutaneous melanins. In addition, there are qualitative and quantitative differences in the structure and pigment chemistry of conjunctival benign nevi, primary acquired melanosis of the conjunctiva (PAM), and conjunctival melanomas. The pump-probe images correlated well with histopathologic features observed in the adjacent H&E-stained sections, and provided a label-free means of discerning conjunctival anatomic features and pathologic benign or malignant tissue. Conclusions. Pump-probe laser microscopy shows promise as an adjuvant diagnostic tool in evaluation of ocular melanocytic lesions based on morphologic correlation with the histopathology results and pigment chemistry. This initial study suggests systematic differences in pigmentation patterns among conjunctival benign nevi, primary acquired melanosis, and melanomas. In addition, pump-probe microscopy has the potential for use as a noninvasive “in vivo” optical biopsy technique to aid clinical and surgical management of conjunctival melanocytic lesions. PMID:24065811

  9. Astemizole Derivatives as Fluorescent Probes for hERG Potassium Channel Imaging.

    PubMed

    Wang, Beilei; Liu, Zhenzhen; Ma, Zhao; Li, Minyong; Du, Lupei

    2016-03-10

    The detection and imaging of hERG potassium channels in living cells can provide useful information for hERG-correlation studies. Herein, three small-molecule fluorescent probes, based on the potent hERG channel inhibitor astemizole, for the imaging of hERG channels in hERG-transfected HEK293 cells (hERG-HEK293) and human colorectal cancer cells (HT-29), are described. These probes are expected to be applied in the physiological and pathological studies of hERG channels. PMID:26985309

  10. Probing Nearby Planetary Systems by Debris Disk Imaging

    NASA Technical Reports Server (NTRS)

    Stapelfeldt, Karl

    2011-01-01

    Many main-sequence stars possess tenuous circumstellar dust clouds believed to trace extrasolar analogs of the Sun's asteroidand Kuiper Belts. While most of these "debris disks" are known only from far-infrared photometry, a growing number of them are now spatially resolved. In this talk, I'll review what is currently known about the structure of debris disks. Using images from the Hubble, Spitzer, and Herschel Space Telescopes, I will show how modeling of these resolved systems can place strong constraints on dust particle properties in the disks. Some of the disks show disturbed structures suggestive of planetary perturbations: specific cases will be discussed where directly-imaged exoplanets are clearly affecting debris disk structure. I'll conclude with thoughts on the future of high contrast exoplanet imaging.

  11. Novel probe for laser-induced breakdown spectroscopy and Raman measurements using an imaging optical fiber

    SciTech Connect

    Marquardt, B.J.; Stratis, D.N.; Angel, S.M.; Cremers, D.A.

    1998-09-01

    A fiber-optic probe designed for remote laser-induced breakdown spectroscopy (LIBS), Raman spectroscopy, and Raman imaging has been developed for the microanalysis of solid samples. The probe incorporates both single-strand optical fibers and an image guide and allows atomic emission and Raman analysis of any spot on a solid sample within a 5 mm diameter field of view. The real-time sample imaging aspects of the probe are demonstrated by measuring LIBS spectra from different regions of a granite sample and by measuring the Raman spectra of individual TiO{sub 2} and Sr(NO{sub 3}){sub 2} particles on a soil substrate. The ability to obtain remote Raman images of the TiO{sub 2} and Sr(NO{sub 3}){sub 2} particles on the soil substrate is also demonstrated. In this paper we discuss the design and implementation of the fiber-optic probe for obtaining LIBS spectra, Raman spectra, and Raman images. {copyright} {ital 1998} {ital Society for Applied Spectroscopy}

  12. The development and evaluation of head probes for optical imaging of the infant head

    NASA Astrophysics Data System (ADS)

    Branco, Gilberto

    The objective of this thesis was to develop and evaluate optical imaging probes for mapping oxygenation and haemodynamic changes in the newborn infant brain. Two imaging approaches are being developed at University College London (UCL): optical topography (surface mapping of the cortex) and optical tomography (volume imaging). Both have the potential to provide information about the function of the normal brain and about a variety of neurophysiologies! abnormalities. Both techniques require an array of optical fibres/fibre bundles to be held in contact with the head, for periods of time from tens of seconds to an hour or more. The design of suitable probes must ensure the comfort and safety of the subject, and provide measurements minimally sensitive to external sources of light and patient motion. A series of prototype adaptable helmets were developed for optical tomography of the premature infant brain using the UCL 32-channel time-resolved system. They were required to attach 32 optical fibre bundles over the infant scalp, and were designed to accommodate infants with a variety of head shapes and sizes, aged between 24-weeks gestational age and term. Continual improvements to the helmet design were introduced following the evaluation of each prototype on infants in the hospital. Data were acquired to generate images revealing the concentration and oxygenation of blood in the brain, and the response of the brain to sensory stimulation. This part of the project also involved designing and testing new methods of acquiring calibration data using reference phantoms. The second focus of the project was the development of probes for use with the UCL frequency-multiplexed near-infrared topography system. This is being used to image functional activation in the infant cortex. A series of probes were developed and experiments were conducted to evaluate their sensitivity to patient motion and to compression of the probe. The probes have been used for a variety of

  13. Highly Selective Two-Photon Fluorescent Probe for Ratiometric Sensing and Imaging Cysteine in Mitochondria.

    PubMed

    Niu, Weifen; Guo, Lei; Li, Yinhui; Shuang, Shaomin; Dong, Chuan; Wong, Man Shing

    2016-02-01

    A novel ratiometric mitochondrial cysteine (Cys)-selective two-photon fluorescence probe has been developed on the basis of a merocyanine as the fluorophore and an acrylate moiety as the biothiol reaction site. The biocompatible and photostable acrylate-functionalized merocyanine probe shows not only a mitochondria-targeting property but also highly selective detection and monitoring of Cys over other biothiols such as homocysteine (Hcy) and glutathione (GSH) and hydrogen sulfide (H2S) in live cells. In addition, this probe exhibits ratiometric fluorescence emission characteristics (F518/F452), which are linearly proportional to Cys concentrations in the range of 0.5-40 μM. More importantly, the probe and its released fluorophore, merocyanine, exhibit strong two-photon excited fluorescence (TPEF) with two-photon action cross-section (Φσmax) of 65.2 GM at 740 nm and 72.6 GM at 760 nm in aqueous medium, respectively, which is highly desirable for high contrast and brightness ratiometric two-photon fluorescence imaging of the living samples. The probe has been successfully applied to ratiometrically image and detect mitochondrial Cys in live cells and intact tissues down to a depth of 150 μm by two-photon fluorescence microscopy. Thus, this ratiometric two-photon fluorescent probe is practically useful for an investigation of Cys in living biological systems. PMID:26717855

  14. Design and Synthesis of Near-infrared Fluorescent Probes for Imaging of Biological Nitroxyl.

    PubMed

    Tan, Yi; Liu, Ruochuan; Zhang, Huatang; Peltier, Raoul; Lam, Yun-Wah; Zhu, Qing; Hu, Yi; Sun, Hongyan

    2015-01-01

    Nitroxyl (HNO), the reduced and protonated form of nitric oxide (NO), has recently been identified as an interesting and important signaling molecule in biological systems. However, research on its biosynthesis and bioactivities are hampered by the lack of versatile HNO detection methods applicable to living cells. In this report, two new near-infrared (NIR) probes were designed and synthesized for HNO imaging in living cells. One of the probes was found to display high sensitivity towards HNO, with up to 67-fold of fluorescence increment after reaction with HNO. The detection limit was determined to be as low as 0.043 μM. The probe displayed high selectivity towards HNO over other biologically related species including metal ions, reactive oxygen species, reactive nitrogen species and reactive sulfur species. Furthermore, the probe was shown to be suitable for imaging of exogenous and endogenous HNO in living cells. Interestingly, the probe was found to be mainly localized in lysosomes. We envision that the new NIR probe described here will serve as a useful tool for further elucidation of the intricate roles of HNO in living cells. PMID:26584764

  15. Investigation of a MMP-2 Activity-Dependent Anchoring Probe for Nuclear Imaging of Cancer

    PubMed Central

    Temma, Takashi; Hanaoka, Hirofumi; Yonezawa, Aki; Kondo, Naoya; Sano, Kohei; Sakamoto, Takeharu; Seiki, Motoharu; Ono, Masahiro; Saji, Hideo

    2014-01-01

    Purpose Since matrix metalloproteinase-2 (MMP-2) is an important marker of tumor malignancy, we developed an original drug design strategy, MMP-2 activity dependent anchoring probes (MDAP), for use in MMP-2 activity imaging, and evaluated the usefulness of this probe in in vitro and in vivo experiments. Methods We designed and synthesized MDAP1000, MDAP3000, and MDAP5000, which consist of 4 independent moieties: RI unit (111In hydrophilic chelate), MMP-2 substrate unit (short peptide), anchoring unit (alkyl chain), and anchoring inhibition unit (polyethylene glycol (PEGn; where n represents the approximate molecular weight, n = 1000, 3000, and 5000). Probe cleavage was evaluated by chromatography after MMP-2 treatment. Cellular uptake of the probes was then measured. Radioactivity accumulation in tumor xenografts was evaluated after intravenous injection of the probes, and probe cleavage was evaluated in tumor homogenates. Results MDAP1000, MDAP3000, and MDAP5000 were cleaved by MMP-2 in a concentration-dependent manner. MDAP3000 pretreated with MMP-2 showed higher accumulation in tumor cells, and was completely blocked by additional treatment with an MMP inhibitor. MDAP3000 exhibited rapid blood clearance and a high tumor accumulation after intravenous injection in a rodent model. Furthermore, pharmacokinetic analysis revealed that MDAP3000 exhibited a considerably slow washout rate from tumors to blood. A certain fraction of cleaved MDAP3000 existed in tumor xenografts in vivo. Conclusions The results indicate the possible usefulness of our MDAP strategy for tumor imaging. PMID:25010662

  16. Highly Selective Two-Photon Fluorescent Probe for Ratiometric Sensing and Imaging Cysteine in Mitochondria.

    PubMed

    Niu, Weifen; Guo, Lei; Li, Yinhui; Shuang, Shaomin; Dong, Chuan; Wong, Man Shing

    2016-02-01

    A novel ratiometric mitochondrial cysteine (Cys)-selective two-photon fluorescence probe has been developed on the basis of a merocyanine as the fluorophore and an acrylate moiety as the biothiol reaction site. The biocompatible and photostable acrylate-functionalized merocyanine probe shows not only a mitochondria-targeting property but also highly selective detection and monitoring of Cys over other biothiols such as homocysteine (Hcy) and glutathione (GSH) and hydrogen sulfide (H2S) in live cells. In addition, this probe exhibits ratiometric fluorescence emission characteristics (F518/F452), which are linearly proportional to Cys concentrations in the range of 0.5-40 μM. More importantly, the probe and its released fluorophore, merocyanine, exhibit strong two-photon excited fluorescence (TPEF) with two-photon action cross-section (Φσmax) of 65.2 GM at 740 nm and 72.6 GM at 760 nm in aqueous medium, respectively, which is highly desirable for high contrast and brightness ratiometric two-photon fluorescence imaging of the living samples. The probe has been successfully applied to ratiometrically image and detect mitochondrial Cys in live cells and intact tissues down to a depth of 150 μm by two-photon fluorescence microscopy. Thus, this ratiometric two-photon fluorescent probe is practically useful for an investigation of Cys in living biological systems.

  17. Imaging via complete cantilever dynamic detection: general dynamic mode imaging and spectroscopy in scanning probe microscopy.

    PubMed

    Somnath, Suhas; Collins, Liam; Matheson, Michael A; Sukumar, Sreenivas R; Kalinin, Sergei V; Jesse, Stephen

    2016-10-14

    We develop and implement a multifrequency spectroscopy and spectroscopic imaging mode, referred to as general dynamic mode (GDM), that captures the complete spatially- and stimulus dependent information on nonlinear cantilever dynamics in scanning probe microscopy (SPM). GDM acquires the cantilever response including harmonics and mode mixing products across the entire broadband cantilever spectrum as a function of excitation frequency. GDM spectra substitute the classical measurements in SPM, e.g. amplitude and phase in lock-in detection. Here, GDM is used to investigate the response of a purely capacitively driven cantilever. We use information theory techniques to mine the data and verify the findings with governing equations and classical lock-in based approaches. We explore the dependence of the cantilever dynamics on the tip-sample distance, AC and DC driving bias. This approach can be applied to investigate the dynamic behavior of other systems within and beyond dynamic SPM. GDM is expected to be useful for separating the contribution of different physical phenomena in the cantilever response and understanding the role of cantilever dynamics in dynamic AFM techniques. PMID:27607339

  18. Imaging via complete cantilever dynamic detection: general dynamic mode imaging and spectroscopy in scanning probe microscopy

    NASA Astrophysics Data System (ADS)

    Somnath, Suhas; Collins, Liam; Matheson, Michael A.; Sukumar, Sreenivas R.; Kalinin, Sergei V.; Jesse, Stephen

    2016-10-01

    We develop and implement a multifrequency spectroscopy and spectroscopic imaging mode, referred to as general dynamic mode (GDM), that captures the complete spatially- and stimulus dependent information on nonlinear cantilever dynamics in scanning probe microscopy (SPM). GDM acquires the cantilever response including harmonics and mode mixing products across the entire broadband cantilever spectrum as a function of excitation frequency. GDM spectra substitute the classical measurements in SPM, e.g. amplitude and phase in lock-in detection. Here, GDM is used to investigate the response of a purely capacitively driven cantilever. We use information theory techniques to mine the data and verify the findings with governing equations and classical lock-in based approaches. We explore the dependence of the cantilever dynamics on the tip-sample distance, AC and DC driving bias. This approach can be applied to investigate the dynamic behavior of other systems within and beyond dynamic SPM. GDM is expected to be useful for separating the contribution of different physical phenomena in the cantilever response and understanding the role of cantilever dynamics in dynamic AFM techniques.

  19. Imaging via complete cantilever dynamic detection: General dynamic mode imaging and spectroscopy in scanning probe microscopy

    DOE PAGES

    Somnath, Suhas; Collins, Liam; Matheson, Michael A.; Sukumar, Sreenivas R.; Kalinin, Sergei V.; Jesse, Stephen

    2016-09-08

    We develop and implement a multifrequency spectroscopy and spectroscopic imaging mode, referred to as general dynamic mode (GDM), that captures the complete spatially- and stimulus dependent information on nonlinear cantilever dynamics in scanning probe microscopy (SPM). GDM acquires the cantilever response including harmonics and mode mixing products across the entire broadband cantilever spectrum as a function of excitation frequency. GDM spectra substitute the classical measurements in SPM, e.g. amplitude and phase in lock-in detection. Here, GDM is used to investigate the response of a purely capacitively driven cantilever. We use information theory techniques to mine the data and verify themore » findings with governing equations and classical lock-in based approaches. We explore the dependence of the cantilever dynamics on the tip–sample distance, AC and DC driving bias. This approach can be applied to investigate the dynamic behavior of other systems within and beyond dynamic SPM. In conclusion, GDM is expected to be useful for separating the contribution of different physical phenomena in the cantilever response and understanding the role of cantilever dynamics in dynamic AFM techniques.« less

  20. Note: Seesaw actuation of atomic force microscope probes for improved imaging bandwidth and displacement range

    SciTech Connect

    Torun, H.; Torello, D.; Degertekin, F. L.

    2011-08-15

    The authors describe a method of actuation for atomic force microscope (AFM) probes to improve imaging speed and displacement range simultaneously. Unlike conventional piezoelectric tube actuation, the proposed method involves a lever and fulcrum ''seesaw'' like actuation mechanism that uses a small, fast piezoelectric transducer. The lever arm of the seesaw mechanism increases the apparent displacement range by an adjustable gain factor, overcoming the standard tradeoff between imaging speed and displacement range. Experimental characterization of a cantilever holder implementing the method is provided together with comparative line scans obtained with contact mode imaging. An imaging bandwidth of 30 kHz in air with the current setup was demonstrated.

  1. Continuously zoom imaging probe for the multi-resolution foveated laparoscope.

    PubMed

    Qin, Yi; Hua, Hong

    2016-04-01

    In modern minimally invasive surgeries (MIS), standard laparoscopes suffer from the tradeoff between the spatial resolution and field of view (FOV). The inability of simultaneously acquiring high-resolution images for accurate operation and wide-angle overviews for situational awareness limits the efficiency and outcome of the MIS. A dual view multi-resolution foveated laparoscope (MRFL) which can simultaneously provide the surgeon with a high-resolution view as well as a wide-angle overview was proposed and demonstrated to have great potential for improving the MIS. Although experiment results demonstrated the high-magnification probe has an adequate magnification for viewing surgical details, the dual-view MRFL is limited to two fixed levels of magnifications. A fine adjustment of the magnification is highly desired for obtaining high resolution images with desired field coverage. In this paper, a high magnification probe with continuous zooming capability without any mechanical moving parts is demonstrated. By taking the advantages of two electrically tunable lenses, one for optical zoom and the other for image focus compensation, the optical magnification of the high-magnification probe varies from 2 × to 3 × compared with that of the wide-angle probe, while the focused object position stays the same as the wide-angle probe. The optical design and the tunable lens analysis are presented, followed by prototype demonstration.

  2. A Two-Photon Ratiometric Fluorescent Probe for Imaging Carboxylesterase 2 in Living Cells and Tissues.

    PubMed

    Jin, Qiang; Feng, Lei; Wang, Dan-Dan; Dai, Zi-Ru; Wang, Ping; Zou, Li-Wei; Liu, Zhi-Hong; Wang, Jia-Yue; Yu, Yang; Ge, Guang-Bo; Cui, Jing-Nan; Yang, Ling

    2015-12-30

    In this study, a two-photon ratiometric fluorescent probe NCEN has been designed and developed for highly selective and sensitive sensing of human carboxylesterase 2 (hCE2) based on the catalytic properties and substrate preference of hCE2. Upon addition of hCE2, the probe could be readily hydrolyzed to release 4-amino-1,8-naphthalimide (NAH), which brings remarkable red-shift in fluorescence (90 nm) spectrum. The newly developed probe exhibits good specificity, ultrahigh sensitivity, and has been successfully applied to determine the real activities of hCE2 in complex biological samples such as cell and tissue preparations. NCEN has also been used for two-photon imaging of intracellular hCE2 in living cells as well as in deep-tissues for the first time, and the results showed that the probe exhibited high ratiometric imaging resolution and deep-tissue imaging depth. All these findings suggested that this probe holds great promise for applications in bioimaging of endogenous hCE2 in living cells and in exploring the biological functions of hCE2 in complex biological systems.

  3. Continuously zoom imaging probe for the multi-resolution foveated laparoscope.

    PubMed

    Qin, Yi; Hua, Hong

    2016-04-01

    In modern minimally invasive surgeries (MIS), standard laparoscopes suffer from the tradeoff between the spatial resolution and field of view (FOV). The inability of simultaneously acquiring high-resolution images for accurate operation and wide-angle overviews for situational awareness limits the efficiency and outcome of the MIS. A dual view multi-resolution foveated laparoscope (MRFL) which can simultaneously provide the surgeon with a high-resolution view as well as a wide-angle overview was proposed and demonstrated to have great potential for improving the MIS. Although experiment results demonstrated the high-magnification probe has an adequate magnification for viewing surgical details, the dual-view MRFL is limited to two fixed levels of magnifications. A fine adjustment of the magnification is highly desired for obtaining high resolution images with desired field coverage. In this paper, a high magnification probe with continuous zooming capability without any mechanical moving parts is demonstrated. By taking the advantages of two electrically tunable lenses, one for optical zoom and the other for image focus compensation, the optical magnification of the high-magnification probe varies from 2 × to 3 × compared with that of the wide-angle probe, while the focused object position stays the same as the wide-angle probe. The optical design and the tunable lens analysis are presented, followed by prototype demonstration. PMID:27446645

  4. Etchable plasmonic nanoparticle probes to image and quantify cellular internalization

    PubMed Central

    Braun, Gary B.; Friman, Tomas; Pang, Hong-Bo; Pallaoro, Alessia; de Mendoza, Tatiana Hurtado; Willmore, Anne-Mari A.; Kotamraju, Venkata Ramana; Mann, Aman P.; She, Zhi-Gang; Sugahara, Kazuki N.; Reich, Norbert O.; Teesalu, Tambet; Ruoslahti, Erkki

    2014-01-01

    There is considerable interest in using nanoparticles as labels or to deliver drugs and other bioactive compounds to cells in vitro and in vivo. Fluorescent imaging, commonly used to study internalization and subcellular localization of nanoparticles, does not allow unequivocal distinction between cell surface-bound and internalized particles, since there is no methodology to turn particles ‘off.’ We have developed a simple technique to rapidly remove silver nanoparticles outside living cells leaving only the internalized pool for imaging or quantification. The silver nanoparticle (AgNP) etching is based on the sensitivity of Ag to a hexacyanoferrate/thiosulfate redox-based destain solution. In demonstration of the technique we present a new class of multicolored plasmonic nanoprobes comprising dye-labeled AgNPs that are exceptionally bright and photostable, carry peptides as model targeting ligands, can be etched rapidly and with minimal toxicity in mice and that show tumour uptake in vivo. PMID:24907927

  5. Nanofabrication of insulated scanning probes for electromechanical imaging in liquid solutions

    NASA Astrophysics Data System (ADS)

    Hyon Noh, Joo; Nikiforov, Maxim; Kalinin, Sergei V.; Vertegel, Alexey A.; Rack, Philip D.

    2010-09-01

    In this paper, the fabrication and electrical and electromechanical characterization of insulated scanning probes have been demonstrated in liquid solutions. The silicon cantilevers were sequentially coated with chromium and silicon dioxide, and the silicon dioxide was selectively etched at the tip apex using focused-electron-beam-induced etching (FEBIE) with XeF2. The chromium layer acted not only as the conductive path from the tip, but also as an etch-resistant layer. This insulated scanning probe fabrication process is compatible with any commercial AFM tip and can be used to easily tailor the scanning probe tip properties because FEBIE does not require lithography. The suitability of the fabricated probes is demonstrated by imaging of a standard topographical calibration grid as well as piezoresponse force microscopy (PFM) and electrical measurements in ambient and liquid environments.

  6. Nanofabrication of insulated scanning probes for electromechanical imaging in liquid solutions

    PubMed Central

    Noh, Joo Hyon; Nikiforov, Maxim; Kalinin, Sergei V.; Vertegel, Alexey A.; Rack, Philip D.

    2011-01-01

    In this paper, the fabrication and electrical and electromechanical characterization of insulated scanning probes have been demonstrated in liquid solutions. The silicon cantilevers were sequentially coated with chromium and silicon dioxide, and the silicon dioxide was selectively etched at tip apex using focused electron beam induced etching (FEBIE) with XeF2 The chromium layer acted not only as the conductive path from the tip, but also as an etch resistant layer. This insulated scanning probe fabrication process is compatible with any commercial AFM tip and can be used to easily tailor the scanning probe tip properties because FEBIE does not require lithography. The suitability of the fabricated probes is demonstrated by imaging of standard topographical calibration grid as well as piezoresponse force microscopy (PFM) and electrical measurements in ambient and liquid environments. PMID:20702930

  7. A simple and non-contact optical imaging probe for evaluation of corneal diseases.

    PubMed

    Hong, Xun Jie Jeesmond; Shinoj, V K; Murukeshan, V M; Baskaran, M; Aung, T

    2015-09-01

    Non-contact imaging techniques are preferred in ophthalmology. Corneal disease is one of the leading causes of blindness worldwide, and a possible way of detection is by analyzing the shape and optical quality of the cornea. Here, a simple and cost-effective, non-contact optical probe system is proposed and illustrated. The probe possesses high spatial resolutions and is non-dependent on coupling medium, which are significant for a clinician and patient friendly investigation. These parameters are crucial, when considering an imaging system for the objective diagnosis and management of corneal diseases. The imaging of the cornea is performed on ex vivo porcine samples and subsequently on small laboratory animals, in vivo. The clinical significance of the proposed study is validated by performing imaging of the New Zealand white rabbit's cornea infected with Pseudomonas.

  8. Near-infrared fluorescent probes for imaging of amyloid plaques in Alzheimer׳s disease.

    PubMed

    Tong, Hongjuan; Lou, Kaiyan; Wang, Wei

    2015-01-01

    One of the early pathological hallmarks of Alzheimer׳s disease (AD) is the deposition of amyloid-β (Aβ) plaques in the brain. There has been a tremendous interest in the development of Aβ plaques imaging probes for early diagnosis of AD in the past decades. Optical imaging, particularly near-infrared fluorescence (NIRF) imaging, has emerged as a safe, low cost, real-time, and widely available technique, providing an attractive approach for in vivo detection of Aβ plaques among many different imaging techniques. In this review, we provide a brief overview of the state-of-the-art development of NIRF Aβ probes and their in vitro and in vivo applications with special focus on design strategies and optical, binding, and brain-kinetic properties. PMID:26579421

  9. A simple and non-contact optical imaging probe for evaluation of corneal diseases

    NASA Astrophysics Data System (ADS)

    Hong, Xun Jie Jeesmond; Shinoj, V. K.; Murukeshan, V. M.; Baskaran, M.; Aung, T.

    2015-09-01

    Non-contact imaging techniques are preferred in ophthalmology. Corneal disease is one of the leading causes of blindness worldwide, and a possible way of detection is by analyzing the shape and optical quality of the cornea. Here, a simple and cost-effective, non-contact optical probe system is proposed and illustrated. The probe possesses high spatial resolutions and is non-dependent on coupling medium, which are significant for a clinician and patient friendly investigation. These parameters are crucial, when considering an imaging system for the objective diagnosis and management of corneal diseases. The imaging of the cornea is performed on ex vivo porcine samples and subsequently on small laboratory animals, in vivo. The clinical significance of the proposed study is validated by performing imaging of the New Zealand white rabbit's cornea infected with Pseudomonas.

  10. Structural Optimization of Zn(II)-Activated MR Imaging Probes

    PubMed Central

    Matosziuk, Lauren M.; Leibowitz, Jonathan H.; Heffern, Marie C.; MacRenaris, Keith W.; Ratner, Mark A.; Meade, Thomas J.

    2013-01-01

    We report the structural optimization and mechanistic investigation of a series of bio-activated MRI contrast agents that transform from low relaxivity to high relaxivity in the presence of Zn(II). The change in relaxivity results from a structural transformation of the complex that alters the coordination environment about the Gd(III) center. Here, we have performed a series of systematic modifications to determine the structure which provides the optimal change in relaxivity in response to the presence of Zn(II). Relaxivity measurements in the presence and absence of Zn(II) were used in conjunction with regarding water access (namely number of water molecules bound) to the Gd(III) center and temperature-dependent 13C NMR spectroscopy to determine how the coordination environment about the Gd(III) center is affected by: the distance between the Zn(II)-binding domain and the Gd(III)-chelate, the number of functional groups on the Zn(II)-binding domain, and the presence of Zn(II). The results of this study provide valuable insight into the elucidation of design principles for future bio-activated MR probes. PMID:23777423

  11. Cyanine-based probe\\tag-peptide pair fluorescence protein imaging and fluorescence protein imaging methods

    DOEpatents

    Mayer-Cumblidge, M. Uljana; Cao, Haishi

    2013-01-15

    A molecular probe comprises two arsenic atoms and at least one cyanine based moiety. A method of producing a molecular probe includes providing a molecule having a first formula, treating the molecule with HgOAc, and subsequently transmetallizing with AsCl.sub.3. The As is liganded to ethanedithiol to produce a probe having a second formula. A method of labeling a peptide includes providing a peptide comprising a tag sequence and contacting the peptide with a biarsenical molecular probe. A complex is formed comprising the tag sequence and the molecular probe. A method of studying a peptide includes providing a mixture containing a peptide comprising a peptide tag sequence, adding a biarsenical probe to the mixture, and monitoring the fluorescence of the mixture.

  12. All-optical pulse-echo ultrasound probe for intravascular imaging (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Colchester, Richard J.; Noimark, Sacha; Mosse, Charles A.; Zhang, Edward Z.; Beard, Paul C.; Parkin, Ivan P.; Papakonstantinou, Ioannis; Desjardins, Adrien E.

    2016-02-01

    High frequency ultrasound probes such as intravascular ultrasound (IVUS) and intracardiac echocardiography (ICE) catheters can be invaluable for guiding minimally invasive medical procedures in cardiology such as coronary stent placement and ablation. With current-generation ultrasound probes, ultrasound is generated and received electrically. The complexities involved with fabricating these electrical probes can result in high costs that limit their clinical applicability. Additionally, it can be challenging to achieve wide transmission bandwidths and adequate wideband reception sensitivity with small piezoelectric elements. Optical methods for transmitting and receiving ultrasound are emerging as alternatives to their electrical counterparts. They offer several distinguishing advantages, including the potential to generate and detect the broadband ultrasound fields (tens of MHz) required for high resolution imaging. In this study, we developed a miniature, side-looking, pulse-echo ultrasound probe for intravascular imaging, with fibre-optic transmission and reception. The axial resolution was better than 70 microns, and the imaging depth in tissue was greater than 1 cm. Ultrasound transmission was performed by photoacoustic excitation of a carbon nanotube/polydimethylsiloxane composite material; ultrasound reception, with a fibre-optic Fabry-Perot cavity. Ex vivo tissue studies, which included healthy swine tissue and diseased human tissue, demonstrated the strong potential of this technique. To our knowledge, this is the first study to achieve an all-optical pulse-echo ultrasound probe for intravascular imaging. The potential for performing all-optical B-mode imaging (2D and 3D) with virtual arrays of transmit/receive elements, and hybrid imaging with pulse-echo ultrasound and photoacoustic sensing are discussed.

  13. Pre-Assembly of Near-Infrared Fluorescent Multivalent Molecular Probes for Biological Imaging.

    PubMed

    Peck, Evan M; Battles, Paul M; Rice, Douglas R; Roland, Felicia M; Norquest, Kathryn A; Smith, Bradley D

    2016-05-18

    A programmable pre-assembly method is described and shown to produce near-infrared fluorescent molecular probes with tunable multivalent binding properties. The modular assembly process threads one or two copies of a tetralactam macrocycle onto a fluorescent PEGylated squaraine scaffold containing a complementary number of docking stations. Appended to the macrocycle periphery are multiple copies of a ligand that is known to target a biomarker. The structure and high purity of each threaded complex was determined by independent spectrometric methods and also by gel electrophoresis. Especially helpful were diagnostic red-shift and energy transfer features in the absorption and fluorescence spectra. The threaded complexes were found to be effective multivalent molecular probes for fluorescence microscopy and in vivo fluorescence imaging of living subjects. Two multivalent probes were prepared and tested for targeting of bone in mice. A pre-assembled probe with 12 bone-targeting iminodiacetate ligands produced more bone accumulation than an analogous pre-assembled probe with six iminodiacetate ligands. Notably, there was no loss in probe fluorescence at the bone target site after 24 h in the living animal, indicating that the pre-assembled fluorescent probe maintained very high mechanical and chemical stability on the skeletal surface. The study shows how this versatile pre-assembly method can be used in a parallel combinatorial manner to produce libraries of near-infrared fluorescent multivalent molecular probes for different types of imaging and diagnostic applications, with incremental structural changes in the number of targeting groups, linker lengths, linker flexibility, and degree of PEGylation.

  14. Focussed ion beam machined cantilever aperture probes for near-field optical imaging.

    PubMed

    Jin, E X; Xu, X

    2008-03-01

    Near-field optical probe is the key element of a near-field scanning optical microscopy (NSOM) system. The key innovation in the first two NSOM experiments (Pohl et al., 1984; Lewis et al., 1984) is the fabrications of a sub-wavelength optical aperture at the apex of a sharply pointed transparent probe tip with a thin metal coating. This paper discusses the routine use of focussed ion beam (FIB) to micro-machine NSOM aperture probes from the commercial silicon nitride cantilevered atomic force microscopy probes. Two FIB micro-machining approaches are used to form a nanoaperture of controllable size and shape at the apex of the tip. The FIB side slicing produces a silicon nitride aperture on the flat-end tips with controllable sizes varying from 120 nm to 30 nm. The FIB head-on drilling creates holes on the aluminium-coated tips with sizes down to 50 nm. Nanoapertures in C and bow tie shapes can also be patterned using the FIB head-on milling method to possibly enhance the optical transmission. A transmission-collection NSOM system is constructed from a commercial atomic force microscopy to characterize the optical resolution of FIB-micro-machined aperture tips. The optical resolution of 78 nm is demonstrated by an aperture probe fabricated by FIB head-on drilling. Simultaneous topography imaging can also be realized using the same probe. By mapping the optical near-field from a bow-tie aperture, optical resolution as small as 59 nm is achieved by an aperture probe fabricated by the FIB side slicing method. Overall, high resolution and reliable optical imaging of routinely FIB-micro-machined aperture probes are demonstrated.

  15. Reversible Fluorescent Probe for Selective Detection and Cell Imaging of Oxidative Stress Indicator Bisulfite.

    PubMed

    Zhang, Yajiao; Guan, Lingmei; Yu, Huan; Yan, Yehan; Du, Libo; Liu, Yang; Sun, Mingtai; Huang, Dejian; Wang, Suhua

    2016-04-19

    In this paper, we report a benzothiazole-functionalized cyanine fluorescence probe and demonstrate that it is selectively reactive to bisulfite, an intermediate indicator for oxidative stress. The selective reaction can be monitored by distinct ratiometric fluorescence variation favorable for cell imaging and visualization. The original probe can be regenerated in high yield through the elimination of bisulfite from the product by peroxides such as hydrogen peroxide, accompanied by fluorescence turning on at 590 nm, showing a potential application for the detection of peroxides. We successfully applied this probe for fluorescence imaging of bisulfite in cancer cells (MCF-7) treated with bisulfite and hydrogen peroxide as well as a selective detection limit of 0.34 μM bisulfite in aqueous solution. PMID:27030140

  16. Probing Ultrafast Nuclear Dynamics in Halomethanes by Time-Resolved Electron and Ion Imaging

    NASA Astrophysics Data System (ADS)

    Ziaee, F.; Rudenko, A.; Rolles, D.; Savelyev, E.; Bomme, C.; Boll, R.; Manschwetus, B.; Erk, B.; Trippel, S.; Wiese, J.; Kuepper, J.; Amini, K.; Lee, J.; Brouard, M.; Brausse, F.; Rouzee, A.; Olshin, P.; Mereshchenko, A.; Lahl, J.; Johnsson, P.; Simon, M.; Marchenko, T.; Holland, D.; Underwood, J.

    2016-05-01

    Femtosecond pump-probe experiments provide opportunities to investigate photochemical reaction dynamics and the resulting changes in molecular structure in detail. Here, we present a study of the UV-induced photodissociation of gas-phase halomethane molecules (CH3 I, CH2 IBr, ...) in a pump-probe arrangement using two complementary probe schemes, either using a femtosecond near-infrared laser or the FLASH free-electron laser. We measured electrons and ions produced during the interaction using a double-sided velocity map imaging spectrometer equipped with a CCD camera for electron detection and with the Pixel Imaging Mass Spectrometry (PImMS) camera for ions, which can record the arrival time for up to four ions per pixel. This project is supported by the DOE, Office of Science, BES, Division of Chemical, Geological, and Biological Sciences.

  17. Spatial Four Wave Mixing, Probe Images, and Fluorescence Signals in Dressed Three-Level System

    NASA Astrophysics Data System (ADS)

    Lan, Huayan; Sun, Jia; Wu, Zhenkun; Zhang, Dan; Zhang, Yiqi; Zheng, Huaibin; Zhang, Yanpeng

    2013-10-01

    We investigate the spatial images of the probe, generated four wave mixing (FWM) signal and the accompanying fluorescence spectrum signal simultaneously in FWM process in a cascade three-level atomic system for the first time. We experimentally observe and theoretically investigate the three spectrum signals versus the probe field as well as the dressing field frequency detunings. Utilizing the experimental results of spectrum signals, the cross phase modulation and the relative position between the weak and strong beams, we analyze the characteristics indicated in the spatial images of probe transmission and FWM, such as focusing or defocusing, shift and splitting in detail. Such studies can be used in all-optical controlled spatial signal transmission.

  18. Universal Molecular Scaffold for Facile Construction of Multivalent and Multimodal Imaging Probes.

    PubMed

    Gai, Yongkang; Xiang, Guangya; Ma, Xiang; Hui, Wenqi; Ouyang, Qin; Sun, Lingyi; Ding, Jiule; Sheng, Jing; Zeng, Dexing

    2016-03-16

    Multivalent and multimodal imaging probes are rapidly emerging as powerful chemical tools for visualizing various biochemical processes. Herein, we described a bifunctional chelator (BFC)-based scaffold that can be used to construct such promising probes concisely. Compared to other reported similar scaffolds, this new BFC scaffold demonstrated two major advantages: (1) significantly simplified synthesis due to the use of this new BFC that can serve as chelator and linker simultaneously; (2) highly efficient synthesis rendered by using either click chemistry and/or total solid-phase synthesis. In addition, the versatile utility of this molecular scaffold has been demonstrated by constructing several multivalent/multimodal imaging probes labeled with various radioisotopes, and the resulting radiotracers demonstrated substantially improved in vivo performance compared to the two individual monomeric counterparts.

  19. Broadband miniature optical ultrasound probe for high resolution vascular tissue imaging.

    PubMed

    Colchester, Richard J; Zhang, Edward Z; Mosse, Charles A; Beard, Paul C; Papakonstantinou, Ioannis; Desjardins, Adrien E

    2015-04-01

    An all-optical ultrasound probe for vascular tissue imaging was developed. Ultrasound was generated by pulsed laser illumination of a functionalized carbon nanotube composite coating on the end face of an optical fiber. Ultrasound was detected with a Fabry-Pérot (FP) cavity on the end face of an adjacent optical fiber. The probe diameter was < 0.84 mm and had an ultrasound bandwidth of ~20 MHz. The probe was translated across the tissue sample to create a virtual linear array of ultrasound transmit/receive elements. At a depth of 3.5 mm, the axial resolution was 64 µm and the lateral resolution was 88 µm, as measured with a carbon fiber target. Vascular tissues from swine were imaged ex vivo and good correspondence to histology was observed. PMID:25909031

  20. Broadband miniature optical ultrasound probe for high resolution vascular tissue imaging

    PubMed Central

    Colchester, Richard J.; Zhang, Edward Z.; Mosse, Charles A.; Beard, Paul C.; Papakonstantinou, Ioannis; Desjardins, Adrien E.

    2015-01-01

    An all-optical ultrasound probe for vascular tissue imaging was developed. Ultrasound was generated by pulsed laser illumination of a functionalized carbon nanotube composite coating on the end face of an optical fiber. Ultrasound was detected with a Fabry-Pérot (FP) cavity on the end face of an adjacent optical fiber. The probe diameter was < 0.84 mm and had an ultrasound bandwidth of ~20 MHz. The probe was translated across the tissue sample to create a virtual linear array of ultrasound transmit/receive elements. At a depth of 3.5 mm, the axial resolution was 64 µm and the lateral resolution was 88 µm, as measured with a carbon fiber target. Vascular tissues from swine were imaged ex vivo and good correspondence to histology was observed. PMID:25909031

  1. Quantitative imaging of disease signatures through radioactive decay signal conversion.

    PubMed

    Thorek, Daniel L J; Ogirala, Anuja; Beattie, Bradley J; Grimm, Jan

    2013-10-01

    In the era of personalized medicine, there is an urgent need for in vivo techniques able to sensitively detect and quantify molecular activities. Sensitive imaging of gamma rays is widely used; however, radioactive decay is a physical constant, and its signal is independent of biological interactions. Here, we introduce a framework of previously uncharacterized targeted and activatable probes that are excited by a nuclear decay-derived signal to identify and measure molecular signatures of disease. We accomplished this by using Cerenkov luminescence, the light produced by β-particle-emitting radionuclides such as clinical positron emission tomography (PET) tracers. Disease markers were detected using nanoparticles to produce secondary Cerenkov-induced fluorescence. This approach reduces background signal compared to conventional fluorescence imaging. In addition to tumor identification from a conventional PET scan, we demonstrate the medical utility of our approach by quantitatively determining prognostically relevant enzymatic activity. This technique can be applied to monitor other markers and represents a shift toward activatable nuclear medicine agents.

  2. Analysis of time-resolved interaction force mode AFM imaging using active and passive probes.

    PubMed

    Giray Oral, Hasan; Parlak, Zehra; Levent Degertekin, F

    2012-09-01

    We present an in-depth analysis of time-resolved interaction force (TRIF) mode imaging for atomic force microscopy (AFM). A nonlinear model of an active AFM probe, performing simultaneous topography and material property imaging on samples with varying elasticity and adhesion is implemented in Simulink®. The model is capable of simulating various imaging modes, probe structures, sample material properties, tip-sample interaction force models, and actuation and feedback schemes. For passive AFM cantilevers, the model is verified by comparing results from the literature. As an example of an active probe, the force sensing integrated readout and active tip (FIRAT) probe is used. Simulation results indicate that the active and damped nature of FIRAT provides a significant level of control over the force applied to the sample, minimizing sample indentation and topography error. Active tip control (ATC) preserves constant contact time during force control for stable contact while preventing the loss of material property information such as elasticity and adhesive force. Simulation results are verified by TRIF mode imaging of the samples with both soft and stiff regions. PMID:22813887

  3. Curcumin analogues as selective fluorescence imaging probes for brown adipose tissue and monitoring browning

    PubMed Central

    Zhang, Xueli; Tian, Yanli; Zhang, Hongbin; Kavishwar, Amol; Lynes, Matthew; Brownell, Anna-Liisa; Sun, Hongbin; Tseng, Yu-Hua; Moore, Anna; Ran, Chongzhao

    2015-01-01

    Manipulation of brown adipose tissue (BAT) and browning of white adipose tissue (WAT) can be promising new approaches to counter metabolic disorder diseases in humans. Imaging probes that could consistently monitor BAT mass and browning of WAT are highly desirable. In the course of our imaging probe screening, we found that BAT could be imaged with curcumin analogues in mice. However, the poor BAT selectivity over WAT and short emissions of the lead probes promoted further lead optimization. Limited uptake mechanism studies suggested that CD36/FAT (fatty acid transporter) probably contributed to the facilitated uptake of the probes. By increasing the stereo-hindrance of the lead compound, we designed CRANAD-29 to extend the emission and increase the facilitated uptake, thus increasing its BAT selectivity. Our data demonstrated that CRANAD-29 had significantly improved selectivity for BAT over WAT, and could be used for imaging BAT mass change in a streptozotocin-induced diabetic mouse model, as well as for monitoring BAT activation under cold exposure. In addition, CRANAD-29 could be used for monitoring the browning of subcutaneous WAT (sWAT) induced by β3-adrenoceptor agonist CL-316, 243. PMID:26269357

  4. A Plasmonic Gold Nanostar Theranostic Probe for In Vivo Tumor Imaging and Photothermal Therapy.

    PubMed

    Liu, Yang; Ashton, Jeffrey R; Moding, Everett J; Yuan, Hsiangkuo; Register, Janna K; Fales, Andrew M; Choi, Jaeyeon; Whitley, Melodi J; Zhao, Xiaoguang; Qi, Yi; Ma, Yan; Vaidyanathan, Ganesan; Zalutsky, Michael R; Kirsch, David G; Badea, Cristian T; Vo-Dinh, Tuan

    2015-01-01

    Nanomedicine has attracted increasing attention in recent years, because it offers great promise to provide personalized diagnostics and therapy with improved treatment efficacy and specificity. In this study, we developed a gold nanostar (GNS) probe for multi-modality theranostics including surface-enhanced Raman scattering (SERS) detection, x-ray computed tomography (CT), two-photon luminescence (TPL) imaging, and photothermal therapy (PTT). We performed radiolabeling, as well as CT and optical imaging, to investigate the GNS probe's biodistribution and intratumoral uptake at both macroscopic and microscopic scales. We also characterized the performance of the GNS nanoprobe for in vitro photothermal heating and in vivo photothermal ablation of primary sarcomas in mice. The results showed that 30-nm GNS have higher tumor uptake, as well as deeper penetration into tumor interstitial space compared to 60-nm GNS. In addition, we found that a higher injection dose of GNS can increase the percentage of tumor uptake. We also demonstrated the GNS probe's superior photothermal conversion efficiency with a highly concentrated heating effect due to a tip-enhanced plasmonic effect. In vivo photothermal therapy with a near-infrared (NIR) laser under the maximum permissible exposure (MPE) led to ablation of aggressive tumors containing GNS, but had no effect in the absence of GNS. This multifunctional GNS probe has the potential to be used for in vivo biosensing, preoperative CT imaging, intraoperative detection with optical methods (SERS and TPL), as well as image-guided photothermal therapy.

  5. A Plasmonic Gold Nanostar Theranostic Probe for In Vivo Tumor Imaging and Photothermal Therapy

    PubMed Central

    Liu, Yang; Ashton, Jeffrey R.; Moding, Everett J.; Yuan, Hsiangkuo; Register, Janna K.; Fales, Andrew M.; Choi, Jaeyeon; Whitley, Melodi J.; Zhao, Xiaoguang; Qi, Yi; Ma, Yan; Vaidyanathan, Ganesan; Zalutsky, Michael R.; Kirsch, David G.; Badea, Cristian T.; Vo-Dinh, Tuan

    2015-01-01

    Nanomedicine has attracted increasing attention in recent years, because it offers great promise to provide personalized diagnostics and therapy with improved treatment efficacy and specificity. In this study, we developed a gold nanostar (GNS) probe for multi-modality theranostics including surface-enhanced Raman scattering (SERS) detection, x-ray computed tomography (CT), two-photon luminescence (TPL) imaging, and photothermal therapy (PTT). We performed radiolabeling, as well as CT and optical imaging, to investigate the GNS probe's biodistribution and intratumoral uptake at both macroscopic and microscopic scales. We also characterized the performance of the GNS nanoprobe for in vitro photothermal heating and in vivo photothermal ablation of primary sarcomas in mice. The results showed that 30-nm GNS have higher tumor uptake, as well as deeper penetration into tumor interstitial space compared to 60-nm GNS. In addition, we found that a higher injection dose of GNS can increase the percentage of tumor uptake. We also demonstrated the GNS probe's superior photothermal conversion efficiency with a highly concentrated heating effect due to a tip-enhanced plasmonic effect. In vivo photothermal therapy with a near-infrared (NIR) laser under the maximum permissible exposure (MPE) led to ablation of aggressive tumors containing GNS, but had no effect in the absence of GNS. This multifunctional GNS probe has the potential to be used for in vivo biosensing, preoperative CT imaging, intraoperative detection with optical methods (SERS and TPL), as well as image-guided photothermal therapy. PMID:26155311

  6. A Plasmonic Gold Nanostar Theranostic Probe for In Vivo Tumor Imaging and Photothermal Therapy.

    PubMed

    Liu, Yang; Ashton, Jeffrey R; Moding, Everett J; Yuan, Hsiangkuo; Register, Janna K; Fales, Andrew M; Choi, Jaeyeon; Whitley, Melodi J; Zhao, Xiaoguang; Qi, Yi; Ma, Yan; Vaidyanathan, Ganesan; Zalutsky, Michael R; Kirsch, David G; Badea, Cristian T; Vo-Dinh, Tuan

    2015-01-01

    Nanomedicine has attracted increasing attention in recent years, because it offers great promise to provide personalized diagnostics and therapy with improved treatment efficacy and specificity. In this study, we developed a gold nanostar (GNS) probe for multi-modality theranostics including surface-enhanced Raman scattering (SERS) detection, x-ray computed tomography (CT), two-photon luminescence (TPL) imaging, and photothermal therapy (PTT). We performed radiolabeling, as well as CT and optical imaging, to investigate the GNS probe's biodistribution and intratumoral uptake at both macroscopic and microscopic scales. We also characterized the performance of the GNS nanoprobe for in vitro photothermal heating and in vivo photothermal ablation of primary sarcomas in mice. The results showed that 30-nm GNS have higher tumor uptake, as well as deeper penetration into tumor interstitial space compared to 60-nm GNS. In addition, we found that a higher injection dose of GNS can increase the percentage of tumor uptake. We also demonstrated the GNS probe's superior photothermal conversion efficiency with a highly concentrated heating effect due to a tip-enhanced plasmonic effect. In vivo photothermal therapy with a near-infrared (NIR) laser under the maximum permissible exposure (MPE) led to ablation of aggressive tumors containing GNS, but had no effect in the absence of GNS. This multifunctional GNS probe has the potential to be used for in vivo biosensing, preoperative CT imaging, intraoperative detection with optical methods (SERS and TPL), as well as image-guided photothermal therapy. PMID:26155311

  7. Exoplanet Direct Imaging: Coronagraph Probe Mission Study EXO-C

    NASA Technical Reports Server (NTRS)

    Stapelfeldt, Karl R.

    2013-01-01

    Flagship mission for spectroscopy of ExoEarths is a long-term priority for space astrophysics (Astro2010). Requires 10(exp 10) contrast at 3 lambda/D separation, ( (is) greater than 10,000 times beyond HST performance) and large telescope (is) greater than 4m aperture. Big step. Mission for spectroscopy of giant planets and imaging of disks requires 10(exp 9) contrast at 3 lambda/D (already demonstrated in lab) and (is) approximately 1.5m telescope. Should be much more affordable, good intermediate step.Various PIs have proposed many versions of the latter mission 17 times since 1999; no unified approach.

  8. Fabrication of a polymer-metal combined atomic force microscopy probe for coarse food surface imaging.

    PubMed

    Kang, Hyen-Wook; Muramatsu, Hiroshi; Kwon, Young-Soo

    2013-05-01

    We fabricated a polymer-metal combined atomic force microscopy (AFM) probe by two steps; a polymeric resin was used at first step, and a metal-ion was used at second step which needs more fabricating time than the resin. At first step, we fabricated a cylindrical base on to a commercial cantilever. At second step, we fabricated a conical probe on to the fabricated cylindrical base. To make the conical probe composed with silver, a 0.2 M aqueous solution of silver nitrate (AgNO3) was used. A 50 microm length polymeric-metallic hybrid tip has been fabricated to observe large bio and food samples. Generally, the AFM images of bio/food samples show cliff-like sharp patters in vertical. However, the AFM image by fabricated long tip shows clear structure of each brown rice flours. As most of commercial tips have three-angular pyramidal, the scanned results should be influenced by the lateral face of the three-angular pyramid, which results in cliff-like images. Because the sample size is large, the side area of the sample was adversely affected by the pyramidal structure during imaging. This problem may be resolved by designing conical structure tips. As the conical structure has no edge, the AFM image becomes clear. The fabricated tip has conical structure, and a clear AFM image was achieved. PMID:23858900

  9. Ptychographic coherent diffractive imaging with orthogonal probe relaxation.

    PubMed

    Odstrcil, M; Baksh, P; Boden, S A; Card, R; Chad, J E; Frey, J G; Brocklesby, W S

    2016-04-18

    Ptychography is a scanning coherent diffractive imaging (CDI) technique that relies upon a high level of stability of the illumination during the course of an experiment. This is particularly an issue for coherent short wavelength sources, where the beam intensity is usually tightly focused on the sample in order to maximize the photon flux density on the illuminated region of the sample and thus a small change in the beam position results in a significant change in illumination of the sample. We present an improved ptychographic method that allows for limited stability of the illumination wavefront and thus significantly improve the reconstruction quality without additional prior knowledge. We have tested our reconstruction method in a proof of concept experiment, where the beam instability of a visible light source was emulated using a piezo driven mirror, and also in a short wavelength microscopy CDI setup using a high harmonic generation source in the extreme ultraviolet range. Our work shows a natural extension of the ptychography method that paves the way to use ptychographic imaging with any limited pointing stability coherent source such as free electron or soft X-ray lasers and improve reconstruction quality of long duration synchrotron experiments. PMID:27137273

  10. Multifunctional gold nanorod theragnostics probed by multi-photon imaging.

    PubMed

    Book Newell, Brittany; Wang, Yuling; Irudayaraj, Joseph

    2012-02-01

    This study exhibits the fabrication of target-specific Gold nanorods (GNRs) coupled with an anti-tumorigenic apoptotic drug and provides tracking of the labeled particles as they migrate through cells and release their drug-load to targeted cancer cells. We utilize the photoluminescence property of GNRs and their ability to be conjugated with multiple agents to transform facile rods to a targeted drug delivery vehicle. GNRs of aspect ratio 2.8 were conjugated with a targeting ligand, folic acid and an anthracycline drug, Doxorubicin. The multifunctional nanorods were then used to target folate receptor expressing cancers cells for the delivery of a concentration dependent dosage of Doxorubicin (DOX). By utilizing the photoluminescence of GNRs and the innate fluorescence of DOX, multi-photon fluorescence lifetime imaging was utilized to monitor the uptake of functionalized nanorods, the release of the drug and its localization in living cells. We show that these nano-vehicles successfully targeted cancer cells over expressing folate receptors and showed low toxicity to control cell lines. Release of DOX was observed in the cytoplasmic region and after 16 h was found to be redistributed in the nucleus resulting in cell death. Our theragnostic approach demonstrates the fabrication of multifunctional GNRs for targeted drug delivery and monitoring of the drug and the vehicle by multi-photon microscopy using fluorescence intensity and lifetime imaging.

  11. Probing peroxisome dynamics and biogenesis by fluorescence imaging.

    PubMed

    Jauregui, Miluska; Kim, Peter K

    2014-03-03

    Peroxisomes are the most recently discovered classical organelles, and only lately have their diverse functions been truly recognized. Peroxisomes are highly dynamic structures, changing both morphologically and in number in response to both extracellular and intracellular signals. This metabolic organelle came to prominence due to the many genetic disorders caused by defects in its biogenesis or enzymatic functions. There is now growing evidence that suggests peroxisomes are involved in lipid biosynthesis, innate immunity, redox homeostasis, and metabolite scavenging, among other functions. Therefore, it is important to have available suitable methods and techniques to visualize and quantify peroxisomes in response to various cellular signals. This unit includes a number of protocols that will enable researchers to image, qualify, and quantify peroxisome numbers and morphology-with both steady-state and time-lapse imaging using mammalian cells. The use of photoactivatable fluorescent proteins to detect and measure peroxisome biogenesis is also described. Altogether, the protocols described here will facilitate understanding of the dynamic changes that peroxisomes undergo in response to various cellular signals.

  12. Probing Endoplasmic Reticulum Dynamics using Fluorescence Imaging and Photobleaching Techniques

    PubMed Central

    Costantini, Lindsey; Snapp, Erik

    2013-01-01

    This UNIT describes approaches and tools for studying the dynamics and organization of endoplasmic reticulum (ER) membranes and proteins in living cells using commercially available widefield and confocal laser scanning microscopes (CLSM). It has been long appreciated that the ER plays a number of key roles in secretory protein biogenesis, calcium regulation, and lipid synthesis. However, study of these processes has been often restricted to biochemical assays that average the behaviors of millions of lysed cells or to imaging static fixed cells. Now, with new fluorescent protein reporter tools, highly sensitive commercial microscopes, and photobleaching techniques, it is possible to interrogate the behaviors of ER proteins, membranes, and stress pathways in single cells with exquisite spatial and temporal resolution. The ER presents a unique set of imaging challenges including the high mobility of ER membranes, a diverse range of dynamic ER structures, and the influence of post-translational modifications on fluorescent protein reporters. Solutions to these challenges are described and considerations for performing photobleaching assays, especially Fluorescence Recovery after Photobleaching (FRAP) and Fluorescence Loss in Photobleaching (FLIP) for ER proteins will be discussed. In addition, ER reporters and ER-specific pharmacologic compounds are presented with a focus on misfolded secretory protein stress and the Unfolded Protein Response (UPR). PMID:24510787

  13. Background-free in-vivo Imaging of Vitamin C using Time-gateable Responsive Probe

    PubMed Central

    Song, Bo; Ye, Zhiqing; Yang, Yajie; Ma, Hua; Zheng, Xianlin; Jin, Dayong; Yuan, Jingli

    2015-01-01

    Sensitive optical imaging of active biomolecules in the living organism requires both a molecular probe specifically responsive to the target and a high-contrast approach to remove the background interference from autofluorescence and light scatterings. Here, a responsive probe for ascorbic acid (vitamin C) has been developed by conjugating two nitroxide radicals with a long-lived luminescent europium complex. The nitroxide radical withholds the probe on its “off” state (barely luminescent), until the presence of vitamin C will switch on the probe by forming its hydroxylamine derivative. The probe showed a linear response to vitamin C concentration with a detection limit of 9.1 nM, two orders of magnitude lower than that achieved using electrochemical methods. Time-gated luminescence microscopy (TGLM) method has further enabled real-time, specific and background-free monitoring of cellular uptake or endogenous production of vitamin C, and mapping of vitamin C in living Daphnia magna. This work suggests a rational design of lanthanide complexes for background-free small animal imaging of biologically functional molecules. PMID:26373894

  14. An acid-cleavable phthalocyanine tetramer as an activatable photosensitiser for photodynamic therapy.

    PubMed

    Chow, Sun Y S; Lo, Pui-Chi; Ng, Dennis K P

    2016-08-16

    An acetal-linked self-quenched zinc(ii) phthalocyanine tetramer has been prepared. In an acidic environment in phosphate buffered saline or inside tumour cells, the phthalocyanine units of the tetramer are separated thereby restoring the fluorescence emission and singlet oxygen production. This response enables this compound to serve as a promising activatable photosensitiser for photodynamic therapy. PMID:27396392

  15. Cascading of molecular logic gates for advanced functions: a self-reporting, activatable photosensitizer.

    PubMed

    Erbas-Cakmak, Sundus; Akkaya, Engin U

    2013-10-18

    Logical progress: Independent molecular logic gates have been designed and characterized. Then, the individual molecular logic gates were coerced to work together within a micelle. Information relay between the two logic gates was achieved through the intermediacy of singlet oxygen. Working together, these concatenated logic gates result in a self-reporting and activatable photosensitizer. GSH=glutathione. PMID:24030974

  16. Frequency Domain Fluorescent Molecular Tomography and Molecular Probes for Small Animal Imaging

    NASA Astrophysics Data System (ADS)

    Kujala, Naresh Gandhi

    Fluorescent molecular tomography (FMT) is a noninvasive biomedical optical imaging that enables 3-dimensional quantitative determination of fluorochromes distributed in biological tissues. There are three methods for imaging large volume tissues based on different light sources: (a) using a light source of constant intensity, through a continuous or constant wave, (b) using a light source that is intensity modulated with a radio frequency (RF), and (c) using ultrafast pulses in the femtosecond range. In this study, we have developed a frequency domain fluorescent molecular tomographic system based on the heterodyne technique, using a single source and detector pair that can be used for small animal imaging. In our system, the intensity of the laser source is modulated with a RF frequency to produce a diffuse photon density wave in the tissue. The phase of the diffuse photon density wave is measured by comparing the reference signal with the signal from the tissue using a phasemeter. The data acquisition was performed by using a Labview program. The results suggest that we can measure the phase change from the heterogeneous inside tissue. Combined with fiber optics and filter sets, the system can be used to sensitively image the targeted fluorescent molecular probes, allowing the detection of cancer at an early stage. We used the system to detect the tumor-targeting molecular probe Alexa Fluor 680 and Alexa Fluor 750 bombesin peptide conjugates in phantoms as well as mouse tissues. We also developed and evaluated fluorescent Bombesin (BBN) probes to target gastrin-releasing peptide (GRP) receptors for optical molecular imaging. GRP receptors are over-expressed in several types of human cancer cells, including breast, prostate, small cell lung, and pancreatic cancers. BBN is a 14 amino acid peptide that is an analogue to human gastrin-releasing peptide that binds specifically to GRPr receptors. BBN conjugates are significant in cancer detection and therapy. The

  17. Validating a new methodology for optical probe design and image registration in fNIRS studies.

    PubMed

    Wijeakumar, Sobanawartiny; Spencer, John P; Bohache, Kevin; Boas, David A; Magnotta, Vincent A

    2015-02-01

    Functional near-infrared spectroscopy (fNIRS) is an imaging technique that relies on the principle of shining near-infrared light through tissue to detect changes in hemodynamic activation. An important methodological issue encountered is the creation of optimized probe geometry for fNIRS recordings. Here, across three experiments, we describe and validate a processing pipeline designed to create an optimized, yet scalable probe geometry based on selected regions of interest (ROIs) from the functional magnetic resonance imaging (fMRI) literature. In experiment 1, we created a probe geometry optimized to record changes in activation from target ROIs important for visual working memory. Positions of the sources and detectors of the probe geometry on an adult head were digitized using a motion sensor and projected onto a generic adult atlas and a segmented head obtained from the subject's MRI scan. In experiment 2, the same probe geometry was scaled down to fit a child's head and later digitized and projected onto the generic adult atlas and a segmented volume obtained from the child's MRI scan. Using visualization tools and by quantifying the amount of intersection between target ROIs and channels, we show that out of 21 ROIs, 17 and 19 ROIs intersected with fNIRS channels from the adult and child probe geometries, respectively. Further, both the adult atlas and adult subject-specific MRI approaches yielded similar results and can be used interchangeably. However, results suggest that segmented heads obtained from MRI scans be used for registering children's data. Finally, in experiment 3, we further validated our processing pipeline by creating a different probe geometry designed to record from target ROIs involved in language and motor processing. PMID:25705757

  18. Development of background-free tame fluorescent probes for intracellular live cell imaging

    PubMed Central

    Alamudi, Samira Husen; Satapathy, Rudrakanta; Kim, Jihyo; Su, Dongdong; Ren, Haiyan; Das, Rajkumar; Hu, Lingna; Alvarado-Martínez, Enrique; Lee, Jung Yeol; Hoppmann, Christian; Peña-Cabrera, Eduardo; Ha, Hyung-Ho; Park, Hee-Sung; Wang, Lei; Chang, Young-Tae

    2016-01-01

    Fluorescence labelling of an intracellular biomolecule in native living cells is a powerful strategy to achieve in-depth understanding of the biomolecule's roles and functions. Besides being nontoxic and specific, desirable labelling probes should be highly cell permeable without nonspecific interactions with other cellular components to warrant high signal-to-noise ratio. While it is critical, rational design for such probes is tricky. Here we report the first predictive model for cell permeable background-free probe development through optimized lipophilicity, water solubility and charged van der Waals surface area. The model was developed by utilizing high-throughput screening in combination with cheminformatics. We demonstrate its reliability by developing CO-1 and AzG-1, a cyclooctyne- and azide-containing BODIPY probe, respectively, which specifically label intracellular target organelles and engineered proteins with minimum background. The results provide an efficient strategy for development of background-free probes, referred to as ‘tame' probes, and novel tools for live cell intracellular imaging. PMID:27321135

  19. Development of background-free tame fluorescent probes for intracellular live cell imaging.

    PubMed

    Alamudi, Samira Husen; Satapathy, Rudrakanta; Kim, Jihyo; Su, Dongdong; Ren, Haiyan; Das, Rajkumar; Hu, Lingna; Alvarado-Martínez, Enrique; Lee, Jung Yeol; Hoppmann, Christian; Peña-Cabrera, Eduardo; Ha, Hyung-Ho; Park, Hee-Sung; Wang, Lei; Chang, Young-Tae

    2016-06-20

    Fluorescence labelling of an intracellular biomolecule in native living cells is a powerful strategy to achieve in-depth understanding of the biomolecule's roles and functions. Besides being nontoxic and specific, desirable labelling probes should be highly cell permeable without nonspecific interactions with other cellular components to warrant high signal-to-noise ratio. While it is critical, rational design for such probes is tricky. Here we report the first predictive model for cell permeable background-free probe development through optimized lipophilicity, water solubility and charged van der Waals surface area. The model was developed by utilizing high-throughput screening in combination with cheminformatics. We demonstrate its reliability by developing CO-1 and AzG-1, a cyclooctyne- and azide-containing BODIPY probe, respectively, which specifically label intracellular target organelles and engineered proteins with minimum background. The results provide an efficient strategy for development of background-free probes, referred to as 'tame' probes, and novel tools for live cell intracellular imaging.

  20. Multi-Functionalized Carbon Nano-onions as Imaging Probes for Cancer Cells.

    PubMed

    Frasconi, Marco; Marotta, Roberto; Markey, Lyn; Flavin, Kevin; Spampinato, Valentina; Ceccone, Giacomo; Echegoyen, Luis; Scanlan, Eoin M; Giordani, Silvia

    2015-12-21

    Carbon-based nanomaterials have attracted much interest during the last decade for biomedical applications. Multimodal imaging probes based on carbon nano-onions (CNOs) have emerged as a platform for bioimaging because of their cell-penetration properties and minimal systemic toxicity. Here, we describe the covalent functionalization of CNOs with fluorescein and folic acid moieties for both imaging and targeting cancer cells. The modified CNOs display high brightness and photostability in aqueous solutions and their selective and rapid uptake in two different cancer cell lines without significant cytotoxicity was demonstrated. The localization of the functionalized CNOs in late-endosomes cell compartments was revealed by a correlative approach with confocal and transmission electron microscopy. Understanding the biological response of functionalized CNOs with the capability to target cancer cells and localize the nanoparticles in the cellular environment, will pave the way for the development of a new generation of imaging probes for future biomedical studies.

  1. A wireless handheld probe with spectrally constrained evolution strategies for diffuse optical imaging of tissue

    NASA Astrophysics Data System (ADS)

    Flexman, M. L.; Kim, H. K.; Stoll, R.; Khalil, M. A.; Fong, C. J.; Hielscher, A. H.

    2012-03-01

    We present a low-cost, portable, wireless diffuse optical imaging device. The handheld device is fast, portable, and can be applied to a wide range of both static and dynamic imaging applications including breast cancer, functional brain imaging, and peripheral artery disease. The continuous-wave probe has four near-infrared wavelengths and uses digital detection techniques to perform measurements at 2.3 Hz. Using a multispectral evolution algorithm for chromophore reconstruction, we can measure absolute oxygenated and deoxygenated hemoglobin concentration as well as scattering in tissue. Performance of the device is demonstrated using a series of liquid phantoms comprised of Intralipid®, ink, and dye.

  2. Imaging single fluorescent molecules at the interface of an optical fiber probe by evanescent wave excitation.

    PubMed

    Fang, X; Tan, W

    1999-08-01

    We have developed a new fluorescent method for single-molecule detection (SMD) and imaging using an optical fiber probe. The fluorophores were excited by the evanescent wave field produced on the core surface of the optical fiber. This was achieved by exposing a section of the core of the optical fiber probe to the fluorophore solution. Both cylindrical and square optical fiber probes were used for SMD. The fluorescent signals were detected by an intensified charge-coupled device. Single rhodamine 6G molecules have been detected. The number of rhodamine 6G molecules imaged by the optical fiber probe showed an excellent linear relationship with the concentrations of the fluorophores. The SMD scheme was also applied to the imaging of biomolecules, such as molecular beacon DNA molecules, labeled with tetramethylrhodamine. Our results have shown that using an optical fiber is an easy yet effective approach to SMD. It represents a simpler fluorescent method for the detection of single-molecules in solution and at an interface.

  3. A ratiometric two-photon fluorescent probe for fluoride ion imaging in living cells and zebrafish.

    PubMed

    Hu, Wei; Zeng, Lingyu; Wang, Yanying; Liu, Zhihong; Ye, Xiaoxue; Li, Chunya

    2016-09-21

    Using 6-hydroxyl-quinoline-2-benzothiazole (HQB) as a two-photon fluorophore and tert-butyldiphenylsilyl as a recognition domain for F(-), a ratiometric two-photon fluorescent fluoride probe, QF, was synthesized and fully characterized. QF displays both one- and two-photon ratiometric responses towards fluoride ions in aqueous solution. QF was enabled to detect exogenous fluoride ions in living cells by a ratiometric method. Two-photon microscopic imaging of fluoride ions in living HeLa cells and zebrafish has also been achieved. QF has been demonstrated to be an excellent fluorescent probe with high selectivity, low cytotoxicity and good photostability.

  4. Imaging pigment chemistry in melanocytic conjunctival lesions with pump-probe microscopy

    NASA Astrophysics Data System (ADS)

    Wilson, Jesse W.; Vajzovic, Lejla; Robles, Francisco E.; Cummings, Thomas J.; Mruthyunjaya, Prithvi; Warren, Warren S.

    2013-03-01

    We extend nonlinear pump-probe microscopy, recently demonstrated to image the microscopic distribution of eumelanin and pheomelanin in unstained skin biopsy sections, to the case of melanocytic conjunctival lesions. The microscopic distribution of pigmentation chemistry serves as a functional indicator of melanocyte activity. In these conjunctival specimens (benign nevi, primary acquired melanoses, and conjunctival melanoma), we have observed pump-probe spectroscopic signatures of eumelanin, pheomelanin, hemoglobin, and surgical ink, in addition to important structural features that differentiate benign from malignant lesions. We will also discuss prospects for an in vivo `optical biopsy' to provide additional information before having to perform invasive procedures.

  5. Histotripsy Lesion Formation Using an Ultrasound Imaging Probe Enabled by a Low-Frequency Pump Transducer.

    PubMed

    Lin, Kuang-Wei; Hall, Timothy L; Xu, Zhen; Cain, Charles A

    2015-08-01

    When histotripsy pulses shorter than 2 cycles are applied, the formation of a dense bubble cloud relies only on the applied peak negative pressure (p-) exceeding the "intrinsic threshold" of the medium (absolute value of 26-30 MPa in most soft tissues). It has been found that a sub-threshold high-frequency probe pulse (3 MHz) can be enabled by a sub-threshold low-frequency pump pulse (500 kHz) where the sum exceeds the intrinsic threshold, thus generating lesion-producing dense bubble clouds ("dual-beam histotripsy"). Here, the feasibility of using an imaging transducer to provide the high-frequency probe pulse in the dual-beam histotripsy approach is investigated. More specifically, an ATL L7-4 imaging transducer (Philips Healthcare, Andover, MA, USA), pulsed by a V-1 Data Acquisition System (Verasonics, Redmond, WA, USA), was used to generate the high-frequency probe pulses. The low-frequency pump pulses were generated by a 20-element 345-kHz array transducer, driven by a custom high-voltage pulser. These dual-beam histotripsy pulses were applied to red blood cell tissue-mimicking phantoms at a pulse repetition frequency of 1 Hz, and optical imaging was used to visualize bubble clouds and lesions generated in the red blood cell phantoms. The results indicated that dense bubble clouds (and resulting lesions) were generated when the p- of the sub-threshold pump and probe pulses combined constructively to exceed the intrinsic threshold. The average size of the smallest reproducible lesions using the imaging probe pulse enabled by the sub-threshold pump pulse was 0.7 × 1.7 mm, whereas that using the supra-threshold pump pulse alone was 1.4 × 3.7 mm. When the imaging transducer was steered laterally, bubble clouds and lesions were steered correspondingly until the combined p- no longer exceeded the intrinsic threshold. These results were also validated with ex vivo porcine liver experiments. Using an imaging transducer for dual-beam histotripsy can have two

  6. Histotripsy Lesion Formation using an Ultrasound Imaging Probe Enabled by a Low-Frequency Pump Transducer

    PubMed Central

    Lin, Kuang-Wei; Hall, Timothy L.; Xu, Zhen; Cain, Charles A.

    2015-01-01

    When applying histotripsy pulses shorter than 2 cycles, the formation of a dense bubble cloud only relies on the applied peak negative pressure (p-) exceeding the “intrinsic threshold” of the medium (absolute value of 26 – 30 MPa in most soft tissue). A previous study conducted by our research group showed that a sub-threshold high-frequency probe pulse (3 MHz) can be enabled by a sub-threshold low-frequency pump pulse (500 kHz) where the sum exceeds the intrinsic threshold, thus generating lesion-producing dense bubble clouds (“dual-beam histotripsy”). This paper investigates the feasibility of using an imaging transducer to provide the high-frequency probe pulse in the dual-beam histotripsy approach. More specifically, an ATL L7–4 imaging transducer, pulsed by a Verasonics V-1 Data Acquisition System, was used to generate the high-frequency probe pulses. The low-frequency pump pulses were generated by a 20-element 345 kHz array transducer, driven by a custom high voltage pulser. These dual-beam histotripsy pulses were applied to red-blood-cell (RBC) tissue-mimicking phantoms at a pulse repetition frequency of 1 Hz, and optical imaging was used to visualize bubble clouds and lesions generated in the RBC phantoms. The results showed that dense bubble clouds (and resulting lesions) were generated when the p- of the sub-threshold pump and probe pulses combined constructively to exceed the intrinsic threshold. The average size of the smallest reproducible lesions using the imaging probe pulse enabled by the sub-threshold pump pulse was 0.7 × 1.7 mm while that using the supra-threshold pump pulse alone was 1.4 × 3.7 mm. When the imaging transducer was steered laterally, bubble clouds and lesions were steered correspondingly until the combined p- no longer exceeded the intrinsic threshold. These results were also validated with ex vivo porcine liver experiments. Using an imaging transducer for dual-beam histotripsy can have two advantages, 1) lesion

  7. Amine-Reactive Fluorene Probes: Synthesis, Optical Characterization, Bioconjugation, and Two-Photon Fluorescence Imaging

    PubMed Central

    2008-01-01

    With the increasing demand for confocal and two-photon fluorescence imaging, the availability of reactive probes that possess high two-photon absorptivity, high fluorescence quantum yield, and high photostability is of paramount importance. To address the demand for better-performing probes, we prepared two-photon absorbing amine-reactive fluorenyl-based probes 2-(9,9-bis(2-(2-methoxyethoxy)ethyl)-2-isothiocyanato-9H-fluoren-7-yl)benzothiazole (1) and 2-(4-(2-(9,9-bis(2-(2-ethoxyethoxy)ethyl)-2-isothiocyanato-9H-fluoren-7-yl)vinyl)phenyl)benzothiazole (2), incorporating the isothiocyanate as a reactive linker. Probe design was augmented by integrating high optical nonlinearities, increased hydrophilicity, and coupling with reactive functional groups for specific targeting of biomolecules, assuring a better impact on two-photon fluorescence microscopy (2PFM) imaging. The isothiocyanate (NCS) derivatives were conjugated with cyclic peptide RGDfK and Reelin protein. The study of the chemical and photophysical properties of the new labeling reagents, as well as the conjugates, is described. The conjugates displayed high chemical stability and photostability. The NCS derivatives had low fluorescence quantum yields, while their bioconjugates exhibited high fluorescence quantum yields, essentially “lighting up” after conjugation. Conventional and 2PFM imaging and fluorescence lifetime imaging (FLIM) of HeLa, NT2, and H1299 cells, incubated with two-photon absorbing amine-reactive probe (1), RGDfK-dye conjugate (7), and Reelin-dye conjugate (6), was demonstrated. PMID:19090700

  8. Novel Strategy for Preparing Dual-Modality Optical/PET Imaging Probes via Photo-Click Chemistry.

    PubMed

    Sun, Lingyi; Ding, Jiule; Xing, Wei; Gai, Yongkang; Sheng, Jing; Zeng, Dexing

    2016-05-18

    Preparation of small molecule based dual-modality probes remains a challenging task due to the complicated synthetic procedure. In this study, a novel concise and generic strategy for preparing dual-modality optical/PET imaging probes via photo-click chemistry was developed, in which the diazole photo-click linker functioned not only as a bridge between the targeting-ligand and the PET imaging moiety, but also as the fluorophore for optical imaging. A dual-modality AE105 peptidic probe was successfully generated via this strategy and subsequently applied in the fluorescent staining of U87MG cells and the (68)Ga based PET imaging of mice bearing U87MG xenograft. In addition, dual-modality monoclonal antibody cetuximab has also been generated via this strategy and labeled with (64)Cu for PET imaging studies, broadening the application of this strategy to include the preparation of macromolecule based imaging probes.

  9. Dataset on FAP-induced emergence of spontaneous metastases and on the preparation of activatable FAP-targeting immunoliposomes to detect the metastases.

    PubMed

    Tansi, Felista L; Rüger, Ronny; Böhm, Claudia; Kontermann, Roland E; Teichgraeber, Ulf K; Fahr, Alfred; Hilger, Ingrid

    2016-12-01

    The underlying data demonstrates that fibroblast activation protein (FAP) paves the way for fibrosarcoma cells, which require the proteolysis of the extracellular matrix (ECM) and basement membranes to intravasate from implanted subcutaneous primary tumors into blood vessels, be transported to distant organs where they extravasate from the blood vessels, reattach and proliferate to metastases. The data additionally shows that FAP, when overexpressed on fibrosarcoma cells induces their invasion and formation of spontaneous metastases in multiple organs, particularly after subcutaneous co-implantation of the FAP-expressing and wildtype fibrosarcoma. The raw and processed data presented herein is related to a research article entitled "Potential of activatable FAP-targeting immunoliposomes in intraoperative imaging of spontaneous metastases" (F.L. Tansi, R. Rüger, C. Böhm, R.E. Kontermann, U.K. Teichgraeber, A. Fahr, I. Hilger, 2016) [1]. Furthermore, evidence for the detection of FAP-expressing tumor cells and cells of the tumor stroma by activatable FAP-targeting liposomes is presented in this dataset. PMID:27642620

  10. Dataset on FAP-induced emergence of spontaneous metastases and on the preparation of activatable FAP-targeting immunoliposomes to detect the metastases.

    PubMed

    Tansi, Felista L; Rüger, Ronny; Böhm, Claudia; Kontermann, Roland E; Teichgraeber, Ulf K; Fahr, Alfred; Hilger, Ingrid

    2016-12-01

    The underlying data demonstrates that fibroblast activation protein (FAP) paves the way for fibrosarcoma cells, which require the proteolysis of the extracellular matrix (ECM) and basement membranes to intravasate from implanted subcutaneous primary tumors into blood vessels, be transported to distant organs where they extravasate from the blood vessels, reattach and proliferate to metastases. The data additionally shows that FAP, when overexpressed on fibrosarcoma cells induces their invasion and formation of spontaneous metastases in multiple organs, particularly after subcutaneous co-implantation of the FAP-expressing and wildtype fibrosarcoma. The raw and processed data presented herein is related to a research article entitled "Potential of activatable FAP-targeting immunoliposomes in intraoperative imaging of spontaneous metastases" (F.L. Tansi, R. Rüger, C. Böhm, R.E. Kontermann, U.K. Teichgraeber, A. Fahr, I. Hilger, 2016) [1]. Furthermore, evidence for the detection of FAP-expressing tumor cells and cells of the tumor stroma by activatable FAP-targeting liposomes is presented in this dataset.

  11. Graphene-based Hall Sensors for direct magnetic imaging by using Scanning Hall Probe Microscope

    NASA Astrophysics Data System (ADS)

    Sonusen, Selda; Aksoy, Seda; Dede, Munir; Oral, Ahmet

    2013-03-01

    Graphene has been attracting great interest due to its unique electronic and mechanical properties for both fundamental and experimental studies since 2004. Graphene is a promising material for many applications in high speed electronic and spintronic devices as well as sensors. Its high mobility makes graphene a good candidate for magnetic imaging in Scanning Hall Probe Microscope (SHPM). Hall probes are used to scan the magnetic samples to image magnetic domains in SHPM. In this work, single layer graphene produced by chemical vapor deposition technique is used to fabricate Hall sensors by optical and the e-beam lithography with sizes from 500 nm to a few micrometers. The Hall crosses are characterized by Raman mapping to make sure that they are made of a single layer graphene. The Graphene Hall Sensors noise spectra is measured as a function of different bias currents and carrier concentrations at 300 K, 77 K and 4.24K. The imaging performance of the Hall sensor will be demonstrated at different temperatures by imaging a garnet crystal using a Low Temperature Scanning Hall Probe Microscope (LT-SHPM).

  12. In vivo cellular-resolution retinal imaging in infants and children using an ultracompact handheld probe

    NASA Astrophysics Data System (ADS)

    Larocca, Francesco; Nankivil, Derek; Dubose, Theodore; Toth, Cynthia A.; Farsiu, Sina; Izatt, Joseph A.

    2016-09-01

    Enabled by adaptive optics, retinal photoreceptor cell imaging is changing our understanding of retinal structure and function, as well as the pathogenesis of numerous ocular diseases. To date, use of this technology has been limited to cooperative adult subjects due to the size, weight and inconvenience of the equipment, thus excluding study of retinal maturation during human development. Here, we report the design and operation of a handheld probe that can perform both scanning laser ophthalmoscopy and optical coherence tomography of the parafoveal photoreceptor structure in infants and children without the need for adaptive optics. The probe, featuring a compact optical design weighing only 94 g, was able to quantify packing densities of parafoveal cone photoreceptors and visualize cross-sectional photoreceptor substructure in children with ages ranging from 14 months to 12 years. The probe will benefit paediatric research by improving the understanding of retinal development, maldevelopment and early onset of disease during human growth.

  13. Design of a rectal probe for diffuse optical spectroscopy imaging for chemotherapy and radiotherapy monitoring

    NASA Astrophysics Data System (ADS)

    van de Giessen, Martijn; Santoro, Ylenia; Mirzaei Zarandi, Soroush; Pigazzi, Alessio; Cerussi, Albert E.; Tromberg, Bruce J.

    2014-03-01

    Diffuse optical spectroscopy imaging (DOSI) has shown great potential for the early detection of non-responding tumors during neoadjuvant chemotherapy in breast cancer, already one day after therapy starts. Patients with rectal cancer receive similar chemotherapy treatment. The rectum geometry and tissue properties of healthy and tumor tissue in the rectum and the requirement of surface contact impose constraints on the probe design. In this work we present the design of a DOSI probe with the aim of early chemotherapy/radiotherapy effectiveness detection in rectal tumors. We show using Monte Carlo simulations and phantom measurements that the colon tissue can be characterized reliably using a source-detector separation in the order of 10 mm. We present a design and rapid prototype of a probe for DOSI measurements that can be mounted on a standard laparoscope and that fits through a standard rectoscope. Using predominantly clinically approved components we aim at fast clinical translation.

  14. Ratiometric emission fluorescent pH probe for imaging of living cells in extreme acidity.

    PubMed

    Niu, Weifen; Fan, Li; Nan, Ming; Li, Zengbo; Lu, Dongtao; Wong, Man Shing; Shuang, Shaomin; Dong, Chuan

    2015-03-01

    A novel ratiometric emission fluorescent probe, 1,1-dimethyl-2-[2-(quinolin-4-yl)vinyl]-1H-benzo[e]indole (QVBI), is facilely synthesized via ethylene bridging of benzoindole and quinoline. The probe exhibits ratiometric fluorescence emission (F(522nm)/F(630nm)) characteristics with pKa 3.27 and linear response to extreme-acidity range of 3.8-2.0. Also, its high fluorescence quantum yield (Φ = 0.89) and large Stokes shift (110 nm) are favorable. Moreover, QVBI possesses highly selective response to H(+) over metal ions and some bioactive molecules, good photostability, and excellent reversibility. The probe has excellent cell membrane permeability and is further applied successfully to monitor pH fluctuations in live cells and imaging extreme acidity in Escherichia coli cells without influence of autofluorescence and native cellular species in biological systems. PMID:25664606

  15. An Aza-Cope Reactivity-Based Fluorescent Probe for Imaging Formaldehyde in Living Cells.

    PubMed

    Brewer, Thomas F; Chang, Christopher J

    2015-09-01

    Formaldehyde (FA) is a reactive carbonyl species (RCS) produced in living systems that has been implicated in epigenetics as well as in the pathologies of various cancers, diabetes, and heart, liver, and neurodegenerative diseases. Traditional methods for biological FA detection rely on sample destruction and/or extensive processing, resulting in a loss of spatiotemporal information. To help address this technological gap, we present the design, synthesis, and biological evaluation of a fluorescent probe for live-cell FA imaging that relies on a FA-induced aza-Cope rearrangement. Formaldehyde probe-1 (FAP-1) is capable of detecting physiologically relevant concentrations of FA in aqueous buffer and in live cells with high selectivity over potentially competing biological analytes. Moreover, FAP-1 can visualize endogenous FA produced by lysine-specific demethylase 1 in a breast cancer cell model, presaging the potential utility of this chemical approach to probe RCS biology.

  16. A robust method for processing scanning probe microscopy images and determining nanoobject position and dimensions.

    PubMed

    Silly, F

    2009-12-01

    Processing of scanning probe microscopy (SPM) images is essential to explore nanoscale phenomena. Image processing and pattern recognition techniques are developed to improve the accuracy and consistency of nanoobject and surface characterization. We present a robust and versatile method to process SPM images and reproducibly estimate nanoobject position and dimensions. This method is using dedicated fits based on the least-square method and the matrix operations. The corresponding algorithms have been implemented in the FabViewer portable application. We illustrate how these algorithms permit not only to correct SPM images but also to precisely determine the position and dimensions of nanocrystals and adatoms on surface. A robustness test is successfully performed using distorted SPM images. PMID:19941561

  17. Interventional multispectral photoacoustic imaging with a clinical linear array ultrasound probe for guiding nerve blocks

    NASA Astrophysics Data System (ADS)

    Xia, Wenfeng; West, Simeon J.; Nikitichev, Daniil I.; Ourselin, Sebastien; Beard, Paul C.; Desjardins, Adrien E.

    2016-03-01

    Accurate identification of tissue structures such as nerves and blood vessels is critically important for interventional procedures such as nerve blocks. Ultrasound imaging is widely used as a guidance modality to visualize anatomical structures in real-time. However, identification of nerves and small blood vessels can be very challenging, and accidental intra-neural or intra-vascular injections can result in significant complications. Multi-spectral photoacoustic imaging can provide high sensitivity and specificity for discriminating hemoglobin- and lipid-rich tissues. However, conventional surface-illumination-based photoacoustic systems suffer from limited sensitivity at large depths. In this study, for the first time, an interventional multispectral photoacoustic imaging (IMPA) system was used to image nerves in a swine model in vivo. Pulsed excitation light with wavelengths in the ranges of 750 - 900 nm and 1150 - 1300 nm was delivered inside the body through an optical fiber positioned within the cannula of an injection needle. Ultrasound waves were received at the tissue surface using a clinical linear array imaging probe. Co-registered B-mode ultrasound images were acquired using the same imaging probe. Nerve identification was performed using a combination of B-mode ultrasound imaging and electrical stimulation. Using a linear model, spectral-unmixing of the photoacoustic data was performed to provide image contrast for oxygenated and de-oxygenated hemoglobin, water and lipids. Good correspondence between a known nerve location and a lipid-rich region in the photoacoustic images was observed. The results indicate that IMPA is a promising modality for guiding nerve blocks and other interventional procedures. Challenges involved with clinical translation are discussed.

  18. Silica micro/nanospheres for theranostics: from bimodal MRI and fluorescent imaging probes to cancer therapy

    PubMed Central

    Walia, Shanka

    2015-01-01

    Summary Nano-theranostics offer remarkable potential for future biomedical technology with simultaneous applications for diagnosis and therapy of disease sites. Through smart and careful chemical modifications of the nanoparticle surface, these can be converted to multifunctional tiny objects which in turn can be used as vehicle for delivering multimodal imaging agents and therapeutic material to specific target sites in vivo. In this sense, bimodal imaging probes that simultaneously enable magnetic resonance imaging and fluorescence imaging have gained tremendous attention because disease sites can be characterized quick and precisely through synergistic multimodal imaging. But such hybrid nanocomposite materials have limitations such as low chemical stability (magnetic component) and harsh cytotoxic effects (fluorescent component) and, hence, require a biocompatible protecting agent. Silica micro/nanospheres have shown promise as protecting agent due to the high stability and low toxicity. This review will cover a full description of MRI-active and fluorescent multifunctional silica micro/nanospheres including the design of the probe, different characterization methods and their application in imaging and treatment in cancer. PMID:25821696

  19. VCAM-1-targeting gold nanoshell probe for photoacoustic imaging of atherosclerotic plaque in mice.

    PubMed

    Rouleau, Leonie; Berti, Romain; Ng, Vanessa W K; Matteau-Pelletier, Carl; Lam, Tina; Saboural, Pierre; Kakkar, Ashok K; Lesage, Frédéric; Rhéaume, Eric; Tardif, Jean-Claude

    2013-01-01

    The development of molecular probes and novel imaging modalities, allowing better resolution and specificity, is associated with an increased potential for molecular imaging of atherosclerotic plaques especially in basic and pre-clinical research applications. In that context, a photoacoustic molecular probe based on gold nanoshells targeting VCAM-1 in mice (immunonanoshells) was designed. The molecular probe was validated in vitro and in vivo, showing no noticeable acute toxic effects. We performed the conjugation of gold nanoshells displaying near-infrared absorption properties with VCAM-1 antibody molecules and PEG to increase their biocompatibility. The resulting immunonanoshells obtained under different conditions of conjugation were then assessed for specificity and sensitivity. Photoacoustic tomography was performed to determine the ability to distinguish gold nanoshells from blood both in phantoms and in vivo. Ex vivo optical projection tomography of hearts and aortas from atherosclerotic and control mice confirmed the selective accumulation of the immunonanoshells in atherosclerotic-prone regions in mice, thus validating the utility of the probe in vivo in small animals for pre-clinical research. These immunonanoshells represent an adequate mean to target atherosclerotic plaques in small animals, leading to new tools to follow the effect of therapies on the progression or regression of the disease. PMID:23109390

  20. Fluorescence imaging of siRNA delivery by peptide nucleic acid-based probe.

    PubMed

    Sato, Takaya; Sato, Yusuke; Iwai, Kenta; Kuge, Shusuke; Teramae, Norio; Nishizawa, Seiichi

    2015-01-01

    We report on the use of a peptide nucleic acid (PNA)-based fluorescent probe for the analysis of siRNA delivery to living cells. The probe, Py-AA-TO, possesses thiazole orange (TO) and pyrene moieties in the C- and N-termini of PNA, and can function as a light-up probe capable of selective binding to 3'-overhanging nucleotides of target siRNAs. The affinity-labeling of the siRNAs with Py-AA-TO facilitates fluorescence imaging of cellular uptake of polymer-based carriers encapsulating the siRNAs (polyplexes) through endocytosis and subsequent sequestration into lysosome. In addition, flow cytometric measurements reveal that the monitoring of Py-AA-TO fluorescence inside the cells is successfully applicable to the analysis of the polyplex disassembly. These promising functions of Py-AA-TO are presented and discussed as a basis for the design of molecular probes for fluorescent imaging and quantitative analysis of the siRNA delivery process. PMID:25864675

  1. Immobilization of human papillomavirus DNA probe for surface plasmon resonance imaging

    NASA Astrophysics Data System (ADS)

    Chong, Xinyuan; Ji, Yanhong; Ma, Suihua; Liu, Le; Liu, Zhiyi; Li, Yao; He, Yonghong; Guo, Jihua

    2009-08-01

    Human papillomavirus (HPV) is a kind of double-stranded DNA virus whose subspecies have diversity. Near 40 kinds of subspecies can invade reproductive organ and cause some high risk disease, such as cervical carcinoma. In order to detect the type of the subspecies of the HPV DNA, we used the parallel scan spectral surface plasmon resonance (SPR) imaging technique, which is a novel type of two- dimensional bio-sensing method based on surface plasmon resonance and is proposed in our previous work, to study the immobilization of the HPV DNA probes on the gold film. In the experiment, four kinds of the subspecies of the HPV DNA (HPV16, HPV18, HPV31, HPV58) probes are fixed on one gold film, and incubate in the constant temperature condition to get a HPV DNA probe microarray. We use the parallel scan spectral SPR imaging system to detect the reflective indices of the HPV DNA subspecies probes. The benefits of this new approach are high sensitive, label-free, strong specificity and high through-put.

  2. Broadband pump-probe imaging spectroscopy applicable to ultrafast single-shot events

    NASA Astrophysics Data System (ADS)

    Minami, Yasuo; Yamaki, Hiromoto; Katayama, Ikufumi; Takeda, Jun

    2014-02-01

    We propose a scheme for frequency-resolved single-shot spectroscopy with an echelon mirror. The echelon mirror is employed to generate spatially encoded time delays for the white-light continuum probe beam; it produces a temporal step of 66 fs and an overall time delay of 33 ps. We demonstrate broadband pump-probe imaging spectroscopy and present time-frequency two-dimensional images of the transient absorption of β-carotene between 420 and 630 nm with single-shot detection. The results show that this technique is a powerful tool for observing the ultrafast, broadband transient dynamics of materials that exhibit irreversible reactions or deterioration by laser pulse irradiation.

  3. A Simple BODIPY-Based Viscosity Probe for Imaging of Cellular Viscosity in Live Cells.

    PubMed

    Su, Dongdong; Teoh, Chai Lean; Gao, Nengyue; Xu, Qing-Hua; Chang, Young-Tae

    2016-01-01

    Intracellular viscosity is a fundamental physical parameter that indicates the functioning of cells. In this work, we developed a simple boron-dipyrromethene (BODIPY)-based probe, BTV, for cellular mitochondria viscosity imaging by coupling a simple BODIPY rotor with a mitochondria-targeting unit. The BTV exhibited a significant fluorescence intensity enhancement of more than 100-fold as the solvent viscosity increased. Also, the probe showed a direct linear relationship between the fluorescence lifetime and the media viscosity, which makes it possible to trace the change of the medium viscosity. Furthermore, it was demonstrated that BTV could achieve practical applicability in the monitoring of mitochondrial viscosity changes in live cells through fluorescence lifetime imaging microscopy (FLIM).

  4. A Nature-Inspired Betalainic Probe for Live-Cell Imaging of Plasmodium-Infected Erythrocytes

    PubMed Central

    Gonçalves, Letícia Christina Pires; Tonelli, Renata Rosito; Bagnaresi, Piero; Mortara, Renato Arruda; Ferreira, Antonio Gilberto; Bastos, Erick Leite

    2013-01-01

    A model betalainic dye was semisynthesized from betanin, the magenta pigment of the red beet, and was effective for live-cell imaging of Plasmodium-infected red blood cells. This water-soluble fluorescent probe is photostable, excitable in the visible region and cell membrane-permeable, and its photophysical properties are not notably pH-sensitive. Fluorescence imaging microscopy of erythrocytes infected with Plasmodium falciparum, a causative agent of malaria in humans, showed that only the parasite was stained. Z-stacking analysis suggested that the probe accumulates proximal to the nucleus of the parasite. Indicaxanthin, one of the natural fluorescent betalains found in the petals of certain flowers, did not stain the parasite or the red blood cell. PMID:23342028

  5. A nature-inspired betalainic probe for live-cell imaging of Plasmodium-infected erythrocytes.

    PubMed

    Gonçalves, Letícia Christina Pires; Tonelli, Renata Rosito; Bagnaresi, Piero; Mortara, Renato Arruda; Ferreira, Antonio Gilberto; Bastos, Erick Leite

    2013-01-01

    A model betalainic dye was semisynthesized from betanin, the magenta pigment of the red beet, and was effective for live-cell imaging of Plasmodium-infected red blood cells. This water-soluble fluorescent probe is photostable, excitable in the visible region and cell membrane-permeable, and its photophysical properties are not notably pH-sensitive. Fluorescence imaging microscopy of erythrocytes infected with Plasmodium falciparum, a causative agent of malaria in humans, showed that only the parasite was stained. Z-stacking analysis suggested that the probe accumulates proximal to the nucleus of the parasite. Indicaxanthin, one of the natural fluorescent betalains found in the petals of certain flowers, did not stain the parasite or the red blood cell. PMID:23342028

  6. A Simple BODIPY-Based Viscosity Probe for Imaging of Cellular Viscosity in Live Cells

    PubMed Central

    Su, Dongdong; Teoh, Chai Lean; Gao, Nengyue; Xu, Qing-Hua; Chang, Young-Tae

    2016-01-01

    Intracellular viscosity is a fundamental physical parameter that indicates the functioning of cells. In this work, we developed a simple boron-dipyrromethene (BODIPY)-based probe, BTV, for cellular mitochondria viscosity imaging by coupling a simple BODIPY rotor with a mitochondria-targeting unit. The BTV exhibited a significant fluorescence intensity enhancement of more than 100-fold as the solvent viscosity increased. Also, the probe showed a direct linear relationship between the fluorescence lifetime and the media viscosity, which makes it possible to trace the change of the medium viscosity. Furthermore, it was demonstrated that BTV could achieve practical applicability in the monitoring of mitochondrial viscosity changes in live cells through fluorescence lifetime imaging microscopy (FLIM). PMID:27589762

  7. A Simple BODIPY-Based Viscosity Probe for Imaging of Cellular Viscosity in Live Cells.

    PubMed

    Su, Dongdong; Teoh, Chai Lean; Gao, Nengyue; Xu, Qing-Hua; Chang, Young-Tae

    2016-01-01

    Intracellular viscosity is a fundamental physical parameter that indicates the functioning of cells. In this work, we developed a simple boron-dipyrromethene (BODIPY)-based probe, BTV, for cellular mitochondria viscosity imaging by coupling a simple BODIPY rotor with a mitochondria-targeting unit. The BTV exhibited a significant fluorescence intensity enhancement of more than 100-fold as the solvent viscosity increased. Also, the probe showed a direct linear relationship between the fluorescence lifetime and the media viscosity, which makes it possible to trace the change of the medium viscosity. Furthermore, it was demonstrated that BTV could achieve practical applicability in the monitoring of mitochondrial viscosity changes in live cells through fluorescence lifetime imaging microscopy (FLIM). PMID:27589762

  8. Plasmonic nanohalo optical probes for highly sensitive imaging of survivin mRNA in living cells.

    PubMed

    Qian, Guang-Sheng; Kang, Bin; Zhang, Zhuo-Lei; Li, Xiang-Ling; Zhao, Wei; Xu, Jing-Juan; Chen, Hong-Yuan

    2016-09-25

    A strategy is designed for sensitive detection of tumor biomarker survivin mRNA based on resonance Rayleigh scattering of a single AuNP nanohalo probe that couples large gold nanoparticles (L-AuNPs, 52 nm) with small AuNPs (S-AuNPs, 18 nm) through the affinity interaction between streptavidin and biotin. This core-satellite plasmon ruler is further applied to imaging survivin mRNA in living cells. PMID:27412908

  9. Plasmonic nanohalo optical probes for highly sensitive imaging of survivin mRNA in living cells.

    PubMed

    Qian, Guang-Sheng; Kang, Bin; Zhang, Zhuo-Lei; Li, Xiang-Ling; Zhao, Wei; Xu, Jing-Juan; Chen, Hong-Yuan

    2016-09-25

    A strategy is designed for sensitive detection of tumor biomarker survivin mRNA based on resonance Rayleigh scattering of a single AuNP nanohalo probe that couples large gold nanoparticles (L-AuNPs, 52 nm) with small AuNPs (S-AuNPs, 18 nm) through the affinity interaction between streptavidin and biotin. This core-satellite plasmon ruler is further applied to imaging survivin mRNA in living cells.

  10. Live-Cell Bioorthogonal Chemical Imaging: Stimulated Raman Scattering Microscopy of Vibrational Probes.

    PubMed

    Wei, Lu; Hu, Fanghao; Chen, Zhixing; Shen, Yihui; Zhang, Luyuan; Min, Wei

    2016-08-16

    Innovations in light microscopy have tremendously revolutionized the way researchers study biological systems with subcellular resolution. In particular, fluorescence microscopy with the expanding choices of fluorescent probes has provided a comprehensive toolkit to tag and visualize various molecules of interest with exquisite specificity and high sensitivity. Although fluorescence microscopy is currently the method of choice for cellular imaging, it faces fundamental limitations for studying the vast number of small biomolecules. This is because common fluorescent labels, which are relatively bulky, could introduce considerable perturbation to or even completely alter the native functions of vital small biomolecules. Hence, despite their immense functional importance, these small biomolecules remain largely undetectable by fluorescence microscopy. To address this challenge, a bioorthogonal chemical imaging platform has recently been introduced. By coupling stimulated Raman scattering (SRS) microscopy, an emerging nonlinear Raman microscopy technique, with tiny and Raman-active vibrational probes (e.g., alkynes and stable isotopes), bioorthogonal chemical imaging exhibits superb sensitivity, specificity, and biocompatibility for imaging small biomolecules in live systems. In this Account, we review recent technical achievements for visualizing a broad spectrum of small biomolecules, including ribonucleosides and deoxyribonucleosides, amino acids, fatty acids, choline, glucose, cholesterol, and small-molecule drugs in live biological systems ranging from individual cells to animal tissues and model organisms. Importantly, this platform is compatible with live-cell biology, thus allowing real-time imaging of small-molecule dynamics. Moreover, we discuss further chemical and spectroscopic strategies for multicolor bioorthogonal chemical imaging, a valuable technique in the era of "omics". As a unique tool for biological discovery, this platform has been applied to

  11. Investigation of SP94 Peptide as a Specific Probe for Hepatocellular Carcinoma Imaging and Therapy

    PubMed Central

    Li, Yanli; Hu, Yan; Xiao, Jie; Liu, Guobing; Li, Xiao; Zhao, Yanzhao; Tan, Hui; Shi, Hongcheng; Cheng, Dengfeng

    2016-01-01

    SP94 (SFSIIHTPILPL), a novel peptide, has shown specific binding to hepatocellular carcinoma (HCC) cells. We aimed to investigate the capability of SP94 as a targeting probe for HCC imaging and therapy following labeling with technetium-99m (99mTc) and rhenium-188 (188Re). HYNIC-SP94 was prepared by solid phase synthesis and then labeled with 99mTc. Cell competitive binding, internalization assay, in vitro and in vivo stability, biodistribution and micro-single photon emission computed tomography /computed tomography (SPECT/CT) imaging studies were performed to investigate the capability of 99mTc tricine-EDDA/HYNIC-SP94 as a specific HCC imaging probe. Initial promising targeting results inspired evaluation of its therapeutic effect when labeled by 188Re. HYNIC-SP94 was then labeled again with 188Re to perform cell apoptosis, microSPECT/CT imaging evaluation and immunohistochemistry. Huh-7 cells exhibited typical apoptotic changes after 188Re irradiation. According to 99mTc tricine-EDDA/HYNIC-SP94 microSPECT/CT imaging, tumor uptake was significantly decreased compared with that of pre-treatment with 188Re-HYNIC-SP94. The immunohistochemistry also displayed obvious necrosis and apoptosis as well as inhibition of proliferation in the 188Re-HYNIC-SP94 treatment group. The results supported that 99mTc tricine-EDDA/HYNIC-SP94 is able to target HCC cells and 188Re-HYNIC- SP94 holds potential as a therapeutic agent for HCC, making 99mTc/188Re-HYNIC-SP94 a promising targeting probe for HCC imaging and therapy. PMID:27649935

  12. Investigation of SP94 Peptide as a Specific Probe for Hepatocellular Carcinoma Imaging and Therapy.

    PubMed

    Li, Yanli; Hu, Yan; Xiao, Jie; Liu, Guobing; Li, Xiao; Zhao, Yanzhao; Tan, Hui; Shi, Hongcheng; Cheng, Dengfeng

    2016-01-01

    SP94 (SFSIIHTPILPL), a novel peptide, has shown specific binding to hepatocellular carcinoma (HCC) cells. We aimed to investigate the capability of SP94 as a targeting probe for HCC imaging and therapy following labeling with technetium-99m ((99m)Tc) and rhenium-188 ((188)Re). HYNIC-SP94 was prepared by solid phase synthesis and then labeled with (99m)Tc. Cell competitive binding, internalization assay, in vitro and in vivo stability, biodistribution and micro-single photon emission computed tomography /computed tomography (SPECT/CT) imaging studies were performed to investigate the capability of (99m)Tc tricine-EDDA/HYNIC-SP94 as a specific HCC imaging probe. Initial promising targeting results inspired evaluation of its therapeutic effect when labeled by (188)Re. HYNIC-SP94 was then labeled again with (188)Re to perform cell apoptosis, microSPECT/CT imaging evaluation and immunohistochemistry. Huh-7 cells exhibited typical apoptotic changes after (188)Re irradiation. According to (99m)Tc tricine-EDDA/HYNIC-SP94 microSPECT/CT imaging, tumor uptake was significantly decreased compared with that of pre-treatment with (188)Re-HYNIC-SP94. The immunohistochemistry also displayed obvious necrosis and apoptosis as well as inhibition of proliferation in the (188)Re-HYNIC-SP94 treatment group. The results supported that (99m)Tc tricine-EDDA/HYNIC-SP94 is able to target HCC cells and (188)Re-HYNIC- SP94 holds potential as a therapeutic agent for HCC, making (99m)Tc/(188)Re-HYNIC-SP94 a promising targeting probe for HCC imaging and therapy. PMID:27649935

  13. Is a new high-resolution probe better than the standard probe for 3D anal sphincter and levator ani imaging?

    PubMed

    Rostaminia, Ghazaleh; White, Dena; Quiroz, Lieschen; Shobeiri, S Abbas

    2015-04-01

    The aim of our study was to determine the accuracy of a new three-dimensional (3D) endoluminal ultrasound probe in assessing the levator ani muscle and anal sphincter complex. A total of 85 patients who had undergone concurrent 3D endovaginal (EVUS) and 3D endoanal (EAUS) ultrasound with both the standard BK 2052 probe and the new high-definition BK 8838 probes were included. For EVUS volumes, the levator ani deficiency (LAD) scores were calculated for each probe. For the EAUS volumes, any defects in the external anal sphincter (EAS) and the internal anal sphincter (IAS) visualized with each probe were recorded. The 3D volumes were evaluated in a blinded fashion. Appropriate statistics were utilized to assess absolute agreements between each pair of imaging modalities. The mean age of the patient population was 59 years (SD ± 10.76), the mean body mass index (BMI) was 28.36 (SD ± 5.99), and the median parity was 2 (range 1, 7). In all, 93% of the patients were Caucasian, 31% had stage 0 or 1 prolapse, while 59% had stage 2 prolapse. The mean total LAD score obtained on EVUS with the standard and the new probes were 11.49 (SD ± 4.94) and 11.53 (SD ± 5.01), respectively, p = 0.3778. Among the 53 patients who had EAUS with both probes, exact agreement for visualization of EAS and IAS for the standard and the new probes was 83% and 98%, respectively. Both transducers can be used for endovaginal imaging of the levator ani muscles interchangeably. Both transducers can be used for endoanal imaging of anal sphincter complex interchangeably.

  14. Bioengineered Probes for Molecular Magnetic Resonance Imaging in the Nervous System

    PubMed Central

    2012-01-01

    The development of molecular imaging probes has changed the nature of neurobiological research. Some of the most notable successes have involved the use of biological engineering techniques for the creation of fluorescent protein derivatives for optical imaging, but recent work has also led to a number of bioengineered probes for magnetic resonance imaging (MRI), the preeminent technique for noninvasive investigation of brain structure and function. Molecular MRI agents are beginning to be applied for experiments in the nervous system, where they have the potential to bridge from molecular to systems or organismic levels of analysis. Compared with canonical synthetic small molecule agents, biomolecular or semibiosynthetic MRI contrast agents offer special advantages due to their amenability to molecular engineering approaches, their properties in some cases as catalysts, and their specificity in targeting and ligand binding. Here, we discuss an expanding list of instances where biological engineering techniques have aided in the design of MRI contrast agents and reporter systems, examining both advantages and limitations of these types of probes for studies in the central nervous system. PMID:22896803

  15. Fluorescent Bisphosphonate and Carboxyphosphonate Probes: A Versatile Imaging Toolkit for Applications in Bone Biology and Biomedicine.

    PubMed

    Sun, Shuting; Błażewska, Katarzyna M; Kadina, Anastasia P; Kashemirov, Boris A; Duan, Xuchen; Triffitt, James T; Dunford, James E; Russell, R Graham G; Ebetino, Frank H; Roelofs, Anke J; Coxon, Fraser P; Lundy, Mark W; McKenna, Charles E

    2016-02-17

    A bone imaging toolkit of 21 fluorescent probes with variable spectroscopic properties, bone mineral binding affinities, and antiprenylation activities has been created, including a novel linking strategy. The linking chemistry allows attachment of a diverse selection of dyes fluorescent in the visible to near-infrared range to any of the three clinically important heterocyclic bisphosphonate bone drugs (risedronate, zoledronate, and minodronate or their analogues). The resultant suite of conjugates offers multiple options to "mix and match" parent drug structure, fluorescence emission wavelength, relative bone affinity, and presence or absence of antiprenylation activity, for bone-related imaging applications.

  16. Dual Frequency Band Annular Probe for Volumetric Pulse-echo Optoacoustic Imaging

    NASA Astrophysics Data System (ADS)

    Kalkhoran, Mohammad Azizian; Varray, François; Vray, Didier

    Optoacoustic (OA) pulse echo (PE) imaging is a hybridized modality that is capable of providing physiological information on the basis of anatomical structure. In this work, we propose a dual frequency band annular probe for backward mode volumetric PE/OA imaging. The performance of this design is evaluated based on the spatio-temporal impulse response, three dimensional steerability of the transducer and point spread function. Optimum settings for number of elements in each ring and maximum steering are suggested. The transducer design and synthetic array beamforming simulation are presented. The resolution performance and reconstruction capabilities are shown with the in-silico measurements.

  17. Fluorescent Bisphosphonate and Carboxyphosphonate Probes: A Versatile Imaging Toolkit for Applications in Bone Biology and Biomedicine.

    PubMed

    Sun, Shuting; Błażewska, Katarzyna M; Kadina, Anastasia P; Kashemirov, Boris A; Duan, Xuchen; Triffitt, James T; Dunford, James E; Russell, R Graham G; Ebetino, Frank H; Roelofs, Anke J; Coxon, Fraser P; Lundy, Mark W; McKenna, Charles E

    2016-02-17

    A bone imaging toolkit of 21 fluorescent probes with variable spectroscopic properties, bone mineral binding affinities, and antiprenylation activities has been created, including a novel linking strategy. The linking chemistry allows attachment of a diverse selection of dyes fluorescent in the visible to near-infrared range to any of the three clinically important heterocyclic bisphosphonate bone drugs (risedronate, zoledronate, and minodronate or their analogues). The resultant suite of conjugates offers multiple options to "mix and match" parent drug structure, fluorescence emission wavelength, relative bone affinity, and presence or absence of antiprenylation activity, for bone-related imaging applications. PMID:26646666

  18. Principal Component Analysis of Spectroscopic Imaging Data in Scanning Probe Microscopy

    SciTech Connect

    Jesse, Stephen; Kalinin, Sergei V

    2009-01-01

    The approach for data analysis in band excitation family of scanning probe microscopies based on principal component analysis (PCA) is explored. PCA utilizes the similarity between spectra within the image to select the relevant response components. For small signal variations within the image, the PCA components coincide with the results of deconvolution using simple harmonic oscillator model. For strong signal variations, the PCA allows effective approach to rapidly process, de-noise and compress the data. The extension of PCA for correlation function analysis is demonstrated. The prospects of PCA as a universal tool for data analysis and representation in multidimensional SPMs are discussed.

  19. Imaging on a Shoestring: Cost-Effective Technologies for Probing Vadose Zone Transport Processes

    NASA Astrophysics Data System (ADS)

    Corkhill, C.; Bridge, J. W.; Barns, G.; Fraser, R.; Romero-Gonzalez, M.; Wilson, R.; Banwart, S.

    2010-12-01

    Key barriers to the widespread uptake of imaging technology for high spatial resolution monitoring of porous media systems are cost and accessibility. X-ray tomography, magnetic resonance imaging (MRI), gamma and neutron radiography require highly specialised equipment, controlled laboratory environments and/or access to large synchrotron facilities. Here we present results from visible light, fluorescence and autoradiographic imaging techniques developed at low cost and applied in standard analytical laboratories, adapted where necessary at minimal capital expense. UV-visible time lapse fluorescence imaging (UV-vis TLFI) in a transparent thin bed chamber enabled microspheres labelled with fluorescent dye and a conservative fluorophore solute (disodium fluorescein) to be measured simultaneously in saturated, partially-saturated and actively draining quartz sand to elucidate empirical values for colloid transport and deposition parameters distributed throughout the flow field, independently of theoretical approximations. Key results include the first experimental quantification of the effects of ionic strength and air-water interfacial area on colloid deposition above a capillary fringe, and the first direct observations of particle mobilisation and redeposition by moving saturation gradients during drainage. UV-vis imaging was also used to study biodegradation and reactive transport in a variety of saturated conditions, applying fluorescence as a probe for oxygen and nitrate concentration gradients, pH, solute transport parameters, reduction of uranium, and mapping of two-dimensional flow fields around a model dipole flow borehole system to validate numerical models. Costs are low: LED excitation sources (< US 50), flow chambers (US 200) and detectors (although a complete scientific-grade CCD set-up costs around US$ 8000, robust datasets can be obtained using a commercial digital SLR camera) mean that set-ups can be flexible to meet changing experimental

  20. Quad-barrel multifunctional electrochemical and ion conductance probe for voltammetric analysis and imaging.

    PubMed

    Nadappuram, Binoy Paulose; McKelvey, Kim; Byers, Joshua C; Güell, Aleix G; Colburn, Alex W; Lazenby, Robert A; Unwin, Patrick R

    2015-04-01

    The fabrication and use of a multifunctional electrochemical probe incorporating two independent carbon working electrodes and two electrolyte-filled barrels, equipped with quasi-reference counter electrodes (QRCEs), in the end of a tapered micrometer-scale pipet is described. This "quad-probe" (4-channel probe) was fabricated by depositing carbon pyrolytically into two diagonally opposite barrels of a laser-pulled quartz quadruple-barrelled pipet. After filling the open channels with electrolyte solution, a meniscus forms at the end of the probe and covers the two working electrodes. The two carbon electrodes can be used to drive local electrochemical reactions within the meniscus while a bias between the QRCEs in the electrolyte channels provides an ion conductance signal that is used to control and position the meniscus on a surface of interest. When brought into contact with a surface, localized high resolution amperometric imaging can be achieved with the two carbon working electrodes with a spatial resolution defined by the meniscus contact area. The substrate can be an insulating material or (semi)conductor, but herein, we focus mainly on conducting substrates that can be connected as a third working electrode. Studies using both aqueous and ionic liquid electrolytes in the probe, together with gold and individual single walled carbon nanotube samples, demonstrate the utility of the technique. Substrate generation-dual tip collection measurements are shown to be characterized by high collection efficiencies (approaching 100%). This hybrid configuration of scanning electrochemical microscopy (SECM) and scanning electrochemical cell microscopy (SECCM) should be powerful for future applications in electrode mapping, as well as in studies of insulating materials as demonstrated by transient spot redox-titration measurements at an electrostatically charged Teflon surface and at a pristine calcite surface, where a functionalized probe is used to follow the

  1. Nanoscale probing of image-dipole interactions in a metallic nanostructure

    PubMed Central

    Ropp, Chad; Cummins, Zachary; Nah, Sanghee; Fourkas, John T.; Shapiro, Benjamin; Waks, Edo

    2015-01-01

    An emitter near a surface induces an image dipole that can modify the observed emission intensity and radiation pattern. These image-dipole effects are generally not taken into account in single-emitter tracking and super-resolved imaging applications. Here we show that the interference between an emitter and its image dipole induces a strong polarization anisotropy and a large spatial displacement of the observed emission pattern. We demonstrate these effects by tracking the emission of a single quantum dot along two orthogonal polarizations as it is deterministically positioned near a silver nanowire. The two orthogonally polarized diffraction spots can be displaced by up to 50 nm, which arises from a Young’s interference effect between the quantum dot and its induced image dipole. We show that the observed spatially varying interference fringe provides a useful measure for correcting image-dipole-induced distortions. These results provide a pathway towards probing and correcting image-dipole effects in near-field imaging applications. PMID:25790228

  2. A computer program for automated step edge motion analysis from scanning probe microscopy images

    NASA Astrophysics Data System (ADS)

    Campbell, Brittany D.; Hu, Xiaoming; Higgins, Steven R.

    2009-04-01

    A computer algorithm was developed to automatically track the displacement of straight step edges between sequential scanning probe microscopy images of single-crystal surfaces. The program utilizes the Canny edge detection algorithm followed by the Hough Transform of the edge map to identify step edges according to their direction, relative to the image axes, and according to their displacement, relative to the image origin. The tracking of individual steps is facilitated by the fact that straight edges in general maintain their direction and therefore, steps of similar displacement but different direction can be sorted. The algorithm is based on the assumption that the rate of image acquisition is much greater than the rate of (mono)layer growth/dissolution, requiring that changes in step displacement are small in successive images. The change in step displacement in sequential images leads directly to the calculation of the step speed. By tabulating all changes in step displacement through a sequence of images, a statistical representation of the step edge data is produced. The program was evaluated using a sequence of 20 atomic force microscopy images from a calcite (104) surface growing from a supersaturated aqueous solution. The program required, in total, 5 CPU-minutes running on a Pentium 4 processor to compute the mean step speed with 60% precision whereas the equivalent number of measurements performed "by hand" required 6 person-hours at 70% precision. For comparable output, the computer program therefore represents a factor of about 100 decrease in required effort.

  3. Chemical Approaches for Advanced Optical Imaging

    NASA Astrophysics Data System (ADS)

    Chen, Zhixing

    Advances in optical microscopy have been constantly expanding our knowledge of biological systems. The achievements therein are a result of close collaborations between physicists/engineers who build the imaging instruments and chemists/biochemists who design the corresponding probe molecules. In this work I present a number of chemical approaches for the development of advanced optical imaging methods. Chapter 1 provides an overview of the recent advances of novel imaging approaches taking advantage of chemical tag technologies. Chapter 2 describes the second-generation covalent trimethoprim-tag as a viable tool for live cell protein-specific labeling and imaging. In Chapter 3 we present a fluorescence lifetime imaging approach to map protein-specific micro-environment in live cells using TMP-Cy3 as a chemical probe. In Chapter 4, we present a method harnessing photo-activatable fluorophores to extend the fundamental depth limit in multi-photon microscopy. Chapter 5 describes the development of isotopically edited alkyne palette for multi-color live cell vibrational imaging of cellular small molecules. These studies exemplify the impact of modern chemical approaches in the development of advanced optical microscopies.

  4. Micro-CT molecular imaging of tumor angiogenesis using a magnetite nano-cluster probe.

    PubMed

    Liu, Ping; Li, Jing; Zhang, Chunfu; Xu, Lisa X

    2013-06-01

    Due to its high resolution, micro-CT is desirable for molecular imaging of tumor angiogenesis. However, the sensitivity of micro-CT to contrast agents is relatively low. Therefore, the purpose of this study is to develop high micro-CT sensitive molecular imaging probes for direct visualization and dynamic monitoring of tumor angiogenesis. To this end, Arg-Gly-Asp (RGD) peptides conjugated magnetite nano clusters (RGD-MNCs) were developed by assembling individual magnetite nano particles into clusters with amphiphilic (maleimide) methoxypoly(ethylene glycol)-b-poly(lactic acid) ((Mal)mPEG-PLA) copolymer and subsequently encoding RGD peptides onto the clusters for specific targeting alpha(v)beta3 integrin. The hydrodynamic size of RGD-MNCs was about 85 nm. To test its specificity, alpha(v)beta3 positive cells (H1299) were incubated with magnetite nano clusters (MNCs), RGD-MNCs or RGD-MNCs competition with free RGD peptides. Prussian Blue staining and inductively coupled plasma optical emission spectrometer (ICP-OES) measurements indicated that the cell uptake of RGD-MNCs was significantly more than that of MNCs, which could be inhibited by free RGD peptides. For detection of tumor angiogenesis, mice bearing H1299 tumors were injected intravenously with RGD-MNCs at the dose of 400 micro mol Fe/kg. Tumor angiogenic hot spots as well as individual angiogenic vessels could be clearly manifested by micro-CT imaging 12 h post injection, which was dynamically monitored with the extension of probe circulation time. Subsequent histological studies of tumor tissues verified that RGD-MNCs registered tumor angiogenic vessels. Our study demonstrated that RGD-MNC probes fabricated in this study could be used to effectively target alpha(v)beta3 integrin. Using high resolution micro-CT in combination with the probes, tumor angiogenesis could be studied dynamically.

  5. Molecular engineering of a TBET-based two-photon fluorescent probe for ratiometric imaging of living cells and tissues.

    PubMed

    Zhou, Liyi; Zhang, Xiaobing; Wang, Qianqian; Lv, Yifan; Mao, Guojiang; Luo, Aili; Wu, Yongxiang; Wu, Yuan; Zhang, Jing; Tan, Weihong

    2014-07-16

    In contrast to one-photon microscopy, two-photon probe-based fluorescent imaging can provide improved three-dimensional spatial localization and increased imaging depth. Consequently, it has become one of the most attractive techniques for studying biological events in living cells and tissues. However, the quantitation of these probes is primarily based on single-emission intensity change, which tends to be affected by a variety of environmental factors. Ratiometric probes, on the other hand, can eliminate these interferences by the built-in correction of the dual emission bands, resulting in a more favorable system for imaging living cells and tissues. Herein, for the first time, we adopted a through-bond energy transfer (TBET) strategy to design and synthesize a small molecular ratiometric two-photon fluorescent probe for imaging living cells and tissues in real time. Specifically, a two-photon fluorophore (D-π-A-structured naphthalene derivative) and a rhodamine B fluorophore are directly connected by electronically conjugated bond to form a TBET probe, or Np-Rh, which shows a target-modulated ratiometric two-photon fluorescence response with highly efficient energy transfer (93.7%) and two well-resolved emission peaks separated by 100 nm. This novel probe was then applied for two-photon imaging of living cells and tissues and showed high ratiometric imaging resolution and deep-tissue imaging depth of 180 μm, thus demonstrating its practical application in biological systems.

  6. A novel ratiometric two-photon fluorescent probe for imaging of Pd2 + ions in living cells and tissues

    NASA Astrophysics Data System (ADS)

    Zhou, Liyi; Hu, Shunqin; Wang, Haifei; Sun, Hongyan; Zhang, Xiaobing

    2016-09-01

    Ratiometric two-photon fluorescent probes can not only eliminate interferences from environmental factors but also achieve deep-tissue imaging with improved spatial localization. To quantitatively track Pd2 + in biosystems, herein, we reported a ratiometric two-photon fluorescent probe, termed as Np-Pd, which based on a D-π-A-structure two-photon fluorophore of the naphthalimide derivative and deprotection of aryl propargyl ethers by palladium species. The probe Np-Pd displayed a more than 25-fold enhancement towards palladium species with high sensitivity and selectivity. Additionally, the probe Np-Pd was further used for fluorescence imaging of Pd2 + ions in living cells and tissues under two-photon excitation (820 nm), which showed large tissue-imaging depth (19.6-184.6 μm), and a high resolution for ratiometric imaging.

  7. A scanning Hall probe microscope for high resolution magnetic imaging down to 300 mK

    NASA Astrophysics Data System (ADS)

    Khotkevych, V. V.; Milošević, M. V.; Bending, S. J.

    2008-12-01

    We present the design, construction, and performance of a low-temperature scanning Hall probe microscope with submicron lateral resolution and a large scanning range. The detachable microscope head is mounted on the cold flange of a commercial H3e-refrigerator (Oxford Instruments, Heliox VT-50) and operates between room temperature and 300 mK. It is fitted with a three-axis slip-stick nanopositioner that enables precise in situ adjustment of the probe location within a 6×6×7 mm3 space. The local magnetic induction at the sample surface is mapped with an easily changeable microfabricated Hall probe [typically GsAs/AlGaAs or AlGaAs/InGaAs/GaAs Hall sensors with integrated scanning tunnel microscopy (STM) tunneling tips] and can achieve minimum detectable fields ⩾10 mG/Hz1/2. The Hall probe is brought into very close proximity to the sample surface by sensing and controlling tunnel currents at the integrated STM tip. The instrument is capable of simultaneous tunneling and Hall signal acquisition in surface-tracking mode. We illustrate the potential of the system with images of superconducting vortices at the surface of a Nb thin film down to 372 mK, and also of labyrinth magnetic-domain patterns of an yttrium iron garnet film captured at room temperature.

  8. A novel, cell-permeable, fluorescent probe for ratiometric imaging of zinc ion.

    PubMed

    Maruyama, Satoko; Kikuchi, Kazuya; Hirano, Tomoya; Urano, Yasuteru; Nagano, Tetsuo

    2002-09-11

    Zn(2+) plays important roles in various biological systems; as a result, the development of tools that can visualize chelatable Zn(2+) has attracted much attention recently. We report here newly synthesized fluorescent sensors for Zn(2+), ZnAF-Rs, whose excitation maximum is shifted by Zn(2+) under physiological conditions. Thus, these sensors enable ratiometric imaging, which is a technique to reduce artifacts by minimizing the influence of extraneous factors on the fluorescence of a probe. Ratiometric measurement can provide precise data, and some probes allow quantitative detection. ZnAF-Rs are the first ratiometric fluorescent sensors for Zn(2+) that enable quantitative analysis under physiological conditions. ZnAF-Rs also possess suitable K(d) for applications, and high selectivity against other biologically relevant cations, especially Ca(2+). Using these probes, changes of intracellular Zn(2+) concentration in cultured cells were monitored successfully. We believe that these probes will be extremely useful in studies on the biological functions of Zn(2+).

  9. Dual-Modal Magnetic Resonance/Fluorescent Zinc Probes for Pancreatic β-Cell Mass Imaging

    PubMed Central

    Stasiuk, Graeme J; Minuzzi, Florencia; Sae-Heng, Myra; Rivas, Charlotte; Juretschke, Hans-Paul; Piemonti, Lorenzo; Allegrini, Peter R; Laurent, Didier; Duckworth, Andrew R; Beeby, Andrew; Rutter, Guy A; Long, Nicholas J

    2015-01-01

    Despite the contribution of changes in pancreatic β-cell mass to the development of all forms of diabetes mellitus, few robust approaches currently exist to monitor these changes prospectively in vivo. Although magnetic-resonance imaging (MRI) provides a potentially useful technique, targeting MRI-active probes to the β cell has proved challenging. Zinc ions are highly concentrated in the secretory granule, but they are relatively less abundant in the exocrine pancreas and in other tissues. We have therefore developed functional dual-modal probes based on transition-metal chelates capable of binding zinc. The first of these, Gd⋅1, binds ZnII directly by means of an amidoquinoline moiety (AQA), thus causing a large ratiometric Stokes shift in the fluorescence from λem=410 to 500 nm with an increase in relaxivity from r1=4.2 up to 4.9 mM−1 s−1. The probe is efficiently accumulated into secretory granules in β-cell-derived lines and isolated islets, but more poorly by non-endocrine cells, and leads to a reduction in T1 in human islets. In vivo murine studies of Gd⋅1 have shown accumulation of the probe in the pancreas with increased signal intensity over 140 minutes. PMID:25736590

  10. Development of Follicle-Stimulating Hormone Receptor Binding Probes to Image Ovarian Xenografts

    PubMed Central

    Lee, Chung-Wein; Guo, Lili; Matei, Daniela; Stantz, Keith

    2015-01-01

    The Follicle-Stimulating Hormone Receptor (FSHR) is used as an imaging biomarker for the detection of ovarian cancer (OC). FSHR is highly expressed on ovarian tumors and involved with cancer development and metastatic signaling pathways. A decapeptide specific to the FSHR extracellular domain is synthesized and conjugated to fluorescent dyes to image OC cells in vitro and tumors xenograft model in vivo. The in vitro binding curve and the average number of FSHR per cell are obtained for OVCAR-3 cells by a high resolution flow cytometer. For the decapeptide, the measured EC50 was 160 μM and the average number of receptors per cell was 1.7 × 107. The decapeptide molecular imaging probe reached a maximum tumor to muscle ratio five hours after intravenous injection and a dose-dependent plateau after 24–48 hours. These results indicate the potential application of a small molecular weight imaging probe specific to ovarian cancer through binding to FSHR. Based on these results, multimeric constructs are being developed to optimize binding to ovarian cells and tumors. PMID:26779384

  11. Molecular imaging of hepatocellular carcinoma xenografts with epidermal growth factor receptor targeted affibody probes.

    PubMed

    Zhao, Ping; Yang, Xiaoyang; Qi, Shibo; Liu, Hongguang; Jiang, Han; Hoppmann, Susan; Cao, Qizhen; Chua, Mei-Sze; So, Samuel K; Cheng, Zhen

    2013-01-01

    Hepatocellular carcinoma (HCC) is a highly aggressive and lethal cancer. It is typically asymptomatic at the early stage, with only 10%-20% of HCC patients being diagnosed early enough for appropriate surgical treatment. The delayed diagnosis of HCC is associated with limited treatment options and much lower survival rates. Therefore, the early and accurate detection of HCC is crucial to improve its currently dismal prognosis. The epidermal growth factor receptor (EGFR) has been reported to be involved in HCC tumorigenesis and to represent an attractive target for HCC imaging and therapy. In this study, an affibody molecule, Ac-Cys-ZEGFR:1907, targeting the extracellular domain of EGFR, was used for the first time to assess its potential to detect HCC xenografts. By evaluating radio- or fluorescent-labeled Ac-Cys-ZEGFR:1907 as a probe for positron emission tomography (PET) or optical imaging of HCC, subcutaneous EGFR-positive HCC xenografts were found to be successfully imaged by the PET probe. Thus, affibody-based PET imaging of EGFR provides a promising approach for detecting HCC in vivo. PMID:23710458

  12. GLP-1 receptor antagonist as a potential probe for pancreatic {beta}-cell imaging

    SciTech Connect

    Mukai, Eri; Toyoda, Kentaro; Kimura, Hiroyuki; Kawashima, Hidekazu; Fujimoto, Hiroyuki; Ueda, Masashi; Temma, Takashi; Hirao, Konomu; Nagakawa, Kenji; Saji, Hideo; Inagaki, Nobuya

    2009-11-20

    We examined exendin(9-39), an antagonist of glucagon-like peptide-1 (GLP-1) receptor (GLP-1R), as a potential probe for imaging of pancreatic {beta}-cells. To evaluate in vitro receptor specificity, binding assay was performed using dispersed mouse islet cells. Binding assay showed competitive inhibition of [{sup 125}I]BH-exendin(9-39) binding by non-radioactive exendin(9-39). To assess in vivo selectivity, the biodistribution was evaluated by intravenous administration of [{sup 125}I]BH-exendin(9-39) to mice. Radioactivity of harvested pancreas reached highest levels at 60 and 120 min among organs examined except lung. Pre-administration of excess non-radioactive exendin(9-39) remarkably and specifically blocked the radioactivity of pancreas. After [{sup 125}I]BH-exendin(9-39) injection into transgenic mice with pancreatic {beta}-cells expressing GFP, fluorescent and radioactive signals of sections of pancreas were evaluated with an image analyzer. Imaging analysis showed that the fluorescent GFP signals and the radioactive signals were correspondingly located. Thus, the GLP-1R antagonist exendin(9-39) may serve as a useful probe for pancreatic {beta}-cell imaging.

  13. Handheld probe integrating laser diode and ultrasound transducer array for ultrasound/photoacoustic dual modality imaging.

    PubMed

    Daoudi, K; van den Berg, P J; Rabot, O; Kohl, A; Tisserand, S; Brands, P; Steenbergen, W

    2014-10-20

    Ultrasound and photoacoustics can be utilized as complementary imaging techniques to improve clinical diagnoses. Photoacoustics provides optical contrast and functional information while ultrasound provides structural and anatomical information. As of yet, photoacoustic imaging uses large and expensive systems, which limits their clinical application and makes the combination costly and impracticable. In this work we present and evaluate a compact and ergonomically designed handheld probe, connected to a portable ultrasound system for inexpensive, real-time dual-modality ultrasound/photoacoustic imaging. The probe integrates an ultrasound transducer array and a highly efficient diode stack laser emitting 130 ns pulses at 805 nm wavelength and a pulse energy of 0.56 mJ, with a high pulse repetition frequency of up to 10 kHz. The diodes are driven by a customized laser driver, which can be triggered externally with a high temporal stability necessary to synchronize the ultrasound detection and laser pulsing. The emitted beam is collimated with cylindrical micro-lenses and shaped using a diffractive optical element, delivering a homogenized rectangular light intensity distribution. The system performance was tested in vitro and in vivo by imaging a human finger joint.

  14. Dual PET and Near-Infrared Fluorescence Imaging Probes as Tools for Imaging in Oncology

    PubMed Central

    An, Fei-Fei; Chan, Mark; Kommidi, Harikrishna; Ting, Richard

    2016-01-01

    OBJECTIVE The purpose of this article is to summarize advances in PET fluorescence resolution, agent design, and preclinical imaging that make a growing case for clinical PET fluorescence imaging. CONCLUSION Existing SPECT, PET, fluorescence, and MRI contrast imaging techniques are already deeply integrated into the management of cancer, from initial diagnosis to the observation and management of metastases. Combined positron-emitting fluorescent contrast agents can convey new or substantial benefits that improve on these proven clinical contrast agents. PMID:27223168

  15. Imaging mitochondrial reactive oxygen species with fluorescent probes: current applications and challenges.

    PubMed

    Zhang, X; Gao, F

    2015-04-01

    Mitochondrial reactive oxygen species (ROS) is a key element in the regulation of several physiological functions and in the development or progression of multiple pathological events. A key task in the study of mitochondrial ROS is to establish reliable methods for measuring the ROS level in mitochondria with high selectivity, sensitivity, and spatiotemporal resolution. Over the last decade, imaging tools with fluorescent indicators from either small-molecule dyes or genetically encoded probes that can be targeted to mitochondria have been developed, which provide a powerful method to visualize and even quantify mitochondrial ROS level not only in live cells, but also in live animals. These innovative tools that have bestowed exciting new insights in mitochondrial ROS biology have been further promoted with the invention of new techniques in indicator design and fluorescent detection. However, these probes present some limitations in terms of specificity, sensitivity, and kinetics; failure to recognize these limitations often results in inappropriate interpretations of data. This review evaluates the recent advances in mitochondrial ROS imaging approaches with emphasis on their proper application and limitations, and highlights the future perspectives in the development of novel fluorescent probes for visualizing all species of ROS.

  16. Non-invasive Imaging of Staphylococcus aureus Infections with a Nuclease-Activated Probe

    PubMed Central

    Hernandez, Frank J.; Huang, Lingyan; Olson, Michael E.; Powers, Kristy M.; Hernandez, Luiza I.; Meyerholz, David K.; Thedens, Daniel R.; Behlke, Mark A.; Horswill, Alexander R.; McNamara, James O.

    2013-01-01

    Technologies that enable the rapid detection and localization of bacterial infections in living animals could address an unmet need for infectious disease diagnostics. We describe a molecular imaging approach for the specific, non-invasive detection of S. aureus based on the activity of its secreted nuclease, micrococcal nuclease (MN). Several short, synthetic oligonucleotides, rendered resistant to mammalian serum nucleases by various chemical modifications, flanked with a fluorophore and quencher, were activated upon degradation by recombinant MN and in S. aureus culture supernatants. A probe consisting of a pair of deoxythymidines flanked by several 2′-O-methyl-modified nucleotides was activated in culture supernatants of S. aureus but not in culture supernatants of several other pathogenic bacteria. Systemic administration of this probe to mice bearing bioluminescent S. aureus muscle infections resulted in probe activation at the infection sites in an MN-dependent manner. This novel bacterial imaging approach has potential clinical applicability for S. aureus and several other medically significant pathogens. PMID:24487433

  17. Nanoparticle-based luminescent probes for intracellular sensing and imaging of pH.

    PubMed

    Schäferling, Michael

    2016-05-01

    Fluorescence imaging microscopy is an essential tool in biomedical research. Meanwhile, various fluorescent probes are available for the staining of cells, cell membranes, and organelles. Though, to monitor intracellular processes and dysfunctions, probes that respond to ubiquitous chemical parameters determining the cellular function such as pH, pO2 , and Ca(2+) are required. This review is focused on the progress in the design, fabrication, and application of photoluminescent nanoprobes for sensing and imaging of pH in living cells. The advantages of using nanoprobes carrying fluorescent pH indicators compared to single molecule probes are discussed as well as their limitations due to the mostly lysosomal uptake by cells. Particular attention is paid to ratiometric dual wavelength nanosensors that enable intrinsic referenced measurements. Referencing and proper calibration procedures are basic prerequisites to carry out reliable quantitative pH determinations in complex samples such as living cells. A variety of examples will be presented that highlight the diverseness of nanocarrier materials (polymers, micelles, silica, quantum dots, carbon dots, gold, photon upconversion nanocrystals, or bacteriophages), fluorescent pH indicators for the weak acidic range, and referenced sensing mechanisms, that have been applied intracellularly up to now. WIREs Nanomed Nanobiotechnol 2016, 8:378-413. doi: 10.1002/wnan.1366 For further resources related to this article, please visit the WIREs website.

  18. Development of a Radioiodinated Triazolopyrimidine Probe for Nuclear Medical Imaging of Fatty Acid Binding Protein 4

    PubMed Central

    Onoe, Satoru; Sampei, Sotaro; Kimura, Ikuo; Ono, Masahiro; Saji, Hideo

    2014-01-01

    Fatty acid binding protein 4 (FABP4) is the most well-characterized FABP isoform. FABP4 regulates inflammatory pathways in adipocytes and macrophages and is involved in both inflammatory diseases and tumor formation. FABP4 expression was recently reported for glioblastoma, where it may participate in disease malignancy. While FABP4 is a potential molecular imaging target, with the exception of a tritium labeled probe there are no reports of other nuclear imaging probes that target this protein. Here we designed and synthesized a nuclear imaging probe, [123I]TAP1, and evaluated its potential as a FABP4 targeting probe in in vitro and in vivo assays. We focused on the unique structure of a triazolopyrimidine scaffold that lacks a carboxylic acid to design the TAP1 probe that can undergo facilitated delivery across cell membranes. The affinity of synthesized TAP1 was measured using FABP4 and 8-anilino-1-naphthalene sulfonic acid. [125I]TAP1 was synthesized by iododestannylation of a precursor, followed by affinity and selectivity measurements using immobilized FABPs. Biodistributions in normal and C6 glioblastoma-bearing mice were evaluated, and excised tumors were subjected to autoradiography and immunohistochemistry. TAP1 and [125I]TAP1 showed high affinity for FABP4 (Ki = 44.5±9.8 nM, Kd = 69.1±12.3 nM). The FABP4 binding affinity of [125I]TAP1 was 11.5- and 35.5-fold higher than for FABP3 and FABP5, respectively. In an in vivo study [125I]TAP1 displayed high stability against deiodination and degradation, and moderate radioactivity accumulation in C6 tumors (1.37±0.24% dose/g 3 hr after injection). The radioactivity distribution profile in tumors partially corresponded to the FABP4 positive area and was also affected by perfusion. The results indicate that [125I]TAP1 could detect FABP4 in vitro and partly in vivo. As such, [125I]TAP1 is a promising lead compound for further refinement for use in in vivo FABP4 imaging. PMID:24732569

  19. Synthetic White-light Imagery for the Wide-field Imager for Solar Probe Plus (WISPR)

    NASA Astrophysics Data System (ADS)

    Liewer, P. C.; Thernisien, A. F.; Vourlidas, A.; Howard, R.; DeForest, C. E.; DeJong, E.; Desai, A.

    2015-12-01

    The Solar Probe Plus trajectory, approaching within 10 solar radii, will enable the white light imager, WISPR, to fly through corona features now only imaged remotely. The dependency of the Thomson scattering on the imaging geometry (distance and angle from the Sun) dictates that the outer WISPR telescope will be sensitive to the emission from plasma close to the spacecraft, in contrast to the situation for imaging from Earth orbit. Thus WISPR will be the first 'local' imager providing a crucial link between the large-scale corona and SPP's in-situ measurements. The high speed at perihelion will provide tomographic-like views of coronal structures at ≤1° resolution. As SPP approaches perihelion, WISPR, with a 95° radial by 58° transverse field of view, will resolve the fine-scale structure with high spatial resolution. To prepare for this unprecedented viewing of the structure of the inner corona, we are creating synthetic white light images and animations from the WISPR viewpoint using the white-light ray-tracing package developed at NRL (available through SolarSoft). We will present simulated observations of multi-strand models of coronal streamers and flux ropes of various size and make comparisons with views from Earth, Solar Orbiter and SPP. Analysis techniques for WISPR images will also be discussed.

  20. NanoCluster Beacons as reporter probes in rolling circle enhanced enzyme activity detection

    NASA Astrophysics Data System (ADS)

    Juul, Sissel; Obliosca, Judy M.; Liu, Cong; Liu, Yen-Liang; Chen, Yu-An; Imphean, Darren M.; Knudsen, Birgitta R.; Ho, Yi-Ping; Leong, Kam W.; Yeh, Hsin-Chih

    2015-04-01

    As a newly developed assay for the detection of endogenous enzyme activity at the single-catalytic-event level, Rolling Circle Enhanced Enzyme Activity Detection (REEAD) has been used to measure enzyme activity in both single human cells and malaria-causing parasites, Plasmodium sp. Current REEAD assays rely on organic dye-tagged linear DNA probes to report the rolling circle amplification products (RCPs), the cost of which may hinder the widespread use of REEAD. Here we show that a new class of activatable probes, NanoCluster Beacons (NCBs), can simplify the REEAD assays. Easily prepared without any need for purification and capable of large fluorescence enhancement upon hybridization, NCBs are cost-effective and sensitive. Compared to conventional fluorescent probes, NCBs are also more photostable. As demonstrated in reporting the human topoisomerases I (hTopI) cleavage-ligation reaction, the proposed NCBs suggest a read-out format attractive for future REEAD-based diagnostics.As a newly developed assay for the detection of endogenous enzyme activity at the single-catalytic-event level, Rolling Circle Enhanced Enzyme Activity Detection (REEAD) has been used to measure enzyme activity in both single human cells and malaria-causing parasites, Plasmodium sp. Current REEAD assays rely on organic dye-tagged linear DNA probes to report the rolling circle amplification products (RCPs), the cost of which may hinder the widespread use of REEAD. Here we show that a new class of activatable probes, NanoCluster Beacons (NCBs), can simplify the REEAD assays. Easily prepared without any need for purification and capable of large fluorescence enhancement upon hybridization, NCBs are cost-effective and sensitive. Compared to conventional fluorescent probes, NCBs are also more photostable. As demonstrated in reporting the human topoisomerases I (hTopI) cleavage-ligation reaction, the proposed NCBs suggest a read-out format attractive for future REEAD-based diagnostics. Electronic

  1. Activatable photodynamic destruction of cancer cells by NIR dye/photosensitizer loaded liposomes.

    PubMed

    Yuan, Ahu; Tang, Xiaolei; Qiu, Xuefeng; Jiang, Ke; Wu, Jinhui; Hu, Yiqiao

    2015-02-25

    The phototoxicity of Chlorin e6 (Ce6) for photodynamic therapy (PDT) was found to be effectively suppressed by indocyanine green (ICG), a near infrared (NIR) dye. Upon NIR laser irradiation at 808 nm, ICG in the liposomes containing ICG and Ce6 could be degraded, while the phototoxicity of Ce6 could be recovered. In addition, we demonstrate that this newly developed liposomal component can be successfully used for activatable PDT to destroy cancer cells in vitro.

  2. Characterization of TCP-1 probes for molecular imaging of colon cancer.

    PubMed

    Liu, Zhonglin; Gray, Brian D; Barber, Christy; Bernas, Michael; Cai, Minying; Furenlid, Lars R; Rouse, Andrew; Patel, Charmi; Banerjee, Bhaskar; Liang, Rongguang; Gmitro, Arthur F; Witte, Marlys H; Pak, Koon Y; Woolfenden, James M

    2016-10-10

    Molecular probes capable of detecting colorectal cancer (CRC) are needed for early CRC diagnosis. The objective of this study was to characterize c[CTPSPFSHC]OH (TCP-1), a small peptide derived from phage display selection, for targeting human CRC xenografts using technetium-99m ((99m)Tc)-labeled TCP-1 and fluorescent cyanine-7 (Cy7)-labeled form of the peptide (Cy7-TCP-1). (99m)Tc-TCP-1 was generated by modifying TCP-1 with succinimidyl-6-hydrazino-nicotinamide (S-HYNIC) followed by radiolabeling. In vitro saturation binding experiments were performed for (99m)Tc-TCP-1 in human HCT116 colon cancer cells. SCID mice with human HCT116 cancer xenografts were imaged with (99m)Tc-TCP-1 or control peptide using a small-animal SPECT imager: Group I (n=5) received no blockade; Group II (n=5) received a blocking dose of non-radiolabeled TCP-1. Group III (n=5) were imaged with (99m)Tc-labeled control peptide (inactive peptide). SCID mice with human PC3 prostate cancer xenografts (Group IV, n=5) were also imaged with (99m)Tc-TCP-1. Eight additional SCID mice bearing HCT116 xenografts in dorsal skinfold window chambers (DSWC) were imaged by direct positron imaging of (18)F-fluorodeoxyglucose ((18)F-FDG) and fluorescence microscopy of Cy7-TCP-1. In vitro(99m)Tc-HYNIC-TCP-1 binding assays on HCT 116 cells indicated a mean Kd of 3.04±0.52nM. In cancer xenografts, (99m)Tc-TCP-1 radioactivity (%ID/g) was 1.01±0.15 in the absence of blockade and was reduced to 0.26±0.04 (P<0.01) with blockade. No radioactive uptake was observed in the PC3 tumors with (99m)Tc-TCP-1 or HCT116 tumors with inactive peptide. Cy7-TCP-1 activity localized not only in metabolically active tumors, as defined by (18)F-FDG imaging, but also in peritumoral microvasculature. In conclusion, TCP-1 probes may have a distinct targeting mechanism with high selectivity for CRC and tumor-associated vasculature. Molecular imaging with TCP-1 probes appears promising to detect malignant colorectal lesions. PMID

  3. Fourier domain pump-probe optical coherence tomography imaging of Melanin

    PubMed Central

    Jacob, Desmond; Shelton, Ryan L.; Applegate, Brian E.

    2010-01-01

    We report the development of a two-color Fourier domain Pump-Probe Optical Coherence Tomography (PPOCT) system. Tissue phantom experiments to characterize the system performance demonstrated imaging depths in excess of 725 μm, nearly comparable to the base Optical Coherence Tomography system. PPOCT A-line rates were also demonstrated in excess of 1 kHz. The physical origin of the PPOCT signal was investigated with a series of experiments which revealed that the signal is a mixture of short and long lifetime component signals. The short lifetime component was attributed to transient absorption while the long lifetime component may be due to a mixture of transient absorption and thermal effects. Ex vivo images of porcine iris demonstrated the potential for imaging melanin in the eye, where cancer of the melanocytes is the most common form of eye cancer in adults. PMID:20588366

  4. Scanned probe imaging of nanoscale magnetism at cryogenic temperatures with a single-spin quantum sensor

    NASA Astrophysics Data System (ADS)

    Pelliccione, Matthew; Jenkins, Alec; Ovartchaiyapong, Preeti; Reetz, Christopher; Emmanuelidu, Eve; Ni, Ni; Bleszynski Jayich, Ania

    The nitrogen vacancy (NV) defect in diamond has emerged as a promising candidate for high resolution magnetic imaging based on its atomic size and quantum-limited sensing capabilities afforded by long spin coherence times. Although the NV center has been successfully implemented as a nanoscale scanning magnetic probe at room temperature, it has remained an outstanding challenge to extend this capability to cryogenic temperatures, where many solid-state systems exhibit non-trivial magnetic order. In this talk, we present NV magnetic imaging at T = 6 K, first benchmarking the technique with a magnetic hard disk sample, then utilizing the technique to image vortices in the iron pnictide superconductor BaFe2(As0.7P0.3)2 with Tc = 30 K. In addition, we discuss other candidate solid-state systems that can benefit from the high spatial resolution and field sensitivity of the scanning NV magnetometer.

  5. Imaging the three orientation variants of the DO22 phase by 3D atom probe microscopy.

    PubMed

    Marteau, L; Pareige, C; Blavette, D

    2001-12-01

    Three-phase NiAlV alloys were investigated using a three-dimensional atom probe. Ageing at 800 degrees C gives rise to the precipitation of two ordered phases within the supersaturated FCC solid solution, namely Ni3Al (L1(2) structure) and Ni3V (DO22 structure). The DO22 phase has three orientation variants which need to be identified in 3DAP images. It is shown that an appropriate choice of analysis site enables us to image the chemical order within both L1(2) and DO22 ordered phases and to distinguish the three orientation variants of the DO22 phase in reconstructed images. The lateral resolution of 3DAP in these experimental conditions was estimated through simple considerations to be less than 0.3 nm.

  6. Synthesis and Bioconjugation of Gold Nanoparticles as Potential Molecular Probes for Light-Based Imaging Techniques

    PubMed Central

    Rayavarapu, Raja Gopal; Petersen, Wilma; Ungureanu, Constantin; Post, Janine N.; van Leeuwen, Ton G.; Manohar, Srirang

    2007-01-01

    We have synthesized and characterized gold nanoparticles (spheres and rods) with optical extinction bands within the “optical imaging window.” The intense plasmon resonant driven absorption and scattering peaks of these nanoparticles make them suitable as contrast agents for optical imaging techniques. Further, we have conjugated these gold nanoparticles to a mouse monoclonal antibody specific to HER2 overexpressing SKBR3 breast carcinoma cells. The bioconjugation protocol uses noncovalent modes of binding based on a combination of electrostatic and hydrophobic interactions of the antibody and the gold surface. We discuss various aspects of the synthesis and bioconjugation protocols and the characterization results of the functionalized nanoparticles. Some proposed applications of these potential molecular probes in the field of biomedical imaging are also discussed. PMID:18354723

  7. Two-dimensional imaging with a single-sided NMR probe.

    PubMed

    Casanova, F; Blümich, B

    2003-07-01

    A new low field unilateral NMR sensor equipped with a two-dimensional gradient coil system was built. A new NMR-MOUSE concept using a simple bar magnet instead of the classical U-shaped geometry was used to produce magnetic field profiles comparatively homogeneous in extended lateral planes defining a suitable field of view for 2D spatial localization. Slice selection along the depth direction is obtained by means of the highly constant static magnetic field gradient produced by this magnet geometry. Implementing a two-dimensional phase-encoding imaging method 2D cross sections of objects were obtained with high spatial resolution. By retuning the probe it was possible to change the depth of the selected slice obtaining a 3D imaging method. The details of the construction of the new device are presented together with imaging tests to show the quality of space encoding. PMID:12852905

  8. Reaction-based fluorescent probes for selective imaging of hydrogen sulfide in living cells.

    PubMed

    Lippert, Alexander R; New, Elizabeth J; Chang, Christopher J

    2011-07-01

    Hydrogen sulfide (H(2)S) is emerging as an important mediator of human physiology and pathology but remains difficult to study, in large part because of the lack of methods for selective monitoring of this small signaling molecule in live biological specimens. We now report a pair of new reaction-based fluorescent probes for selective imaging of H(2)S in living cells that exploit the H(2)S-mediated reduction of azides to fluorescent amines. Sulfidefluor-1 (SF1) and Sulfidefluor-2 (SF2) respond to H(2)S by a turn-on fluorescence signal enhancement and display high selectivity for H(2)S over other biologically relevant reactive sulfur, oxygen, and nitrogen species. In addition, SF1 and SF2 can be used to detect H(2)S in both water and live cells, providing a potentially powerful approach for probing H(2)S chemistry in biological systems.

  9. Development of a c-scan photoacoutsic imaging probe for prostate cancer detection

    NASA Astrophysics Data System (ADS)

    Valluru, Keerthi S.; Chinni, Bhargava K.; Rao, Navalgund A.; Bhatt, Shweta; Dogra, Vikram S.

    2011-03-01

    Prostate cancer is the second leading cause of death in American men after lung cancer. The current screening procedures include Digital Rectal Exam (DRE) and Prostate Specific Antigen (PSA) test, along with Transrectal Ultrasound (TRUS). All suffer from low sensitivity and specificity in detecting prostate cancer in early stages. There is a desperate need for a new imaging modality. We are developing a prototype transrectal photoacoustic imaging probe to detect prostate malignancies in vivo that promises high sensitivity and specificity. To generate photoacoustic (PA) signals, the probe utilizes a high energy 1064 nm laser that delivers light pulses onto the prostate at 10Hz with 10ns duration through a fiber optic cable. The designed system will generate focused C-scan planar images using acoustic lens technology. A 5 MHz custom fabricated ultrasound sensor array located in the image plane acquires the focused PA signals, eliminating the need for any synthetic aperture focusing. The lens and sensor array design was optimized towards this objective. For fast acquisition times, a custom built 16 channel simultaneous backend electronics PCB has been developed. It consists of a low-noise variable gain amplifier and a 16 channel ADC. Due to the unavailability of 2d ultrasound arrays, in the current implementation several B-scan (depth-resolved) data is first acquired by scanning a 1d array, which is then processed to reconstruct either 3d volumetric images or several C-scan planar images. Experimental results on excised tissue using a in-vitro prototype of this technology are presented to demonstrate the system capability in terms of resolution and sensitivity.

  10. Linear-array-based photoacoustic imaging of human microcirculation with a range of high frequency transducer probes

    NASA Astrophysics Data System (ADS)

    Zafar, Haroon; Breathnach, Aedán; Subhash, Hrebesh M.; Leahy, Martin J.

    2015-05-01

    Photoacoustic imaging (PAI) with a linear-array-based probe can provide a convenient means of imaging the human microcirculation within its native structural context and adds functional information. PAI using a multielement linear transducer array combined with multichannel collecting system was used for in vivo volumetric imaging of the blood microcirculation, the total concentration of hemoglobin (HbT), and the hemoglobin oxygen saturation (sO2) within human tissue. Three-dimensional (3-D) PA and ultrasound (US) volumetric scans were acquired from the forearm skin by linearly translating the transducer with a stepper motor over a region of interest, while capturing two-dimensional images using 15, 21, and 40 MHz frequency transducer probes. For the microvasculature imaging, PA images were acquired at 800- and 1064-nm wavelengths. For the HbT and sO2 estimates, PA images were collected at 750- and 850-nm wavelengths. 3-D microcirculation, HbT, and sO2 maps of the forearm skin were obtained from normal subjects. The linear-array-based PAI has been found promising in terms of resolution, imaging depth, and imaging speed for in vivo microcirculation imaging within human skin. We believe that a reflection type probe, similar to existing clinical US probes, is most likely to succeed in real clinical applications. Its advantages include ease of use, speed, and familiarity for radiographers and clinicians.

  11. Water-soluble colorimetric and ratiometric fluorescent probe for selective imaging of palladium species in living cells.

    PubMed

    Liu, Wei; Jiang, Jie; Chen, Chunyang; Tang, Xiaoliang; Shi, Jinmin; Zhang, Peng; Zhang, Kaiming; Li, Zhiqi; Dou, Wei; Yang, Lizi; Liu, Weisheng

    2014-12-01

    A novel water-soluble colorimetric and ratiometric fluorescent probe was synthesized and applied to imaging palladium species under physiological conditions in phosphate buffered saline (PBS) containing less than 1% organic cosolvent without adding any additional reagents. Based on palladium triggered terminal propargyl ethers cleavage reaction, the probe exhibited a high selectivity and sensitivity for palladium species of all the typical oxidation states (0, +2, +4), with a low detection limit (25 nM, 2.7 μg/L) and an obvious color change. Furthermore, the probe was successfully used for ratiometric fluorescence imaging of palladium in living cells.

  12. Applications of the Single-probe: Mass Spectrometry Imaging and Single Cell Analysis under Ambient Conditions

    PubMed Central

    Rao, Wei; Pan, Ning; Yang, Zhibo

    2016-01-01

    Mass spectrometry imaging (MSI) and in-situ single cell mass spectrometry (SCMS) analysis under ambient conditions are two emerging fields with great potential for the detailed mass spectrometry (MS) analysis of biomolecules from biological samples. The single-probe, a miniaturized device with integrated sampling and ionization capabilities, is capable of performing both ambient MSI and in-situ SCMS analysis. For ambient MSI, the single-probe uses surface micro-extraction to continually conduct MS analysis of the sample, and this technique allows the creation of MS images with high spatial resolution (8.5 µm) from biological samples such as mouse brain and kidney sections. Ambient MSI has the advantage that little to no sample preparation is needed before the analysis, which reduces the amount of potential artifacts present in data acquisition and allows a more representative analysis of the sample to be acquired. For in-situ SCMS, the single-probe tip can be directly inserted into live eukaryotic cells such as HeLa cells, due to the small sampling tip size (< 10 µm), and this technique is capable of detecting a wide range of metabolites inside individual cells at near real-time. SCMS enables a greater sensitivity and accuracy of chemical information to be acquired at the single cell level, which could improve our understanding of biological processes at a more fundamental level than previously possible. The single-probe device can be potentially coupled with a variety of mass spectrometers for broad ranges of MSI and SCMS studies. PMID:27341402

  13. Articulated dual modality photoacoustic and optical coherence tomography probe for preclinical and clinical imaging (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Liu, Mengyang; Zabihian, Behrooz; Weingast, Jessika; Hermann, Boris; Chen, Zhe; Zhang, Edward Z.; Beard, Paul C.; Pehamberger, Hubert; Drexler, Wolfgang

    2016-03-01

    The combination of photoacoustic tomography (PAT) with optical coherence tomography (OCT) has seen steady progress over the past few years. With the benchtop and semi-benchtop configurations, preclinical and clinical results have been demonstrated, paving the way for wider applications using dual modality PAT/OCT systems. However, as for the most updated semi-benchtop PAT/OCT system which employs a Fabry-Perot polymer film sensor, it is restricted to only human palm imaging due to the limited flexibility of the probe. The passband limit of the polymer film sensor further restricts the OCT source selection and reduces the sensitivity of the combined OCT system. To tackle these issues, we developed an articulated PAT/OCT probe for both preclinical and clinical applications. In the probe design, the sample arm of OCT sub-system and the interrogation part of the PAT sub-system are integrated into one compact unit. The polymer film sensor has a quick release function so that before each OCT scan, the sensor can be taken off to avoid the sensitivity drop and artefacts in OCT. The holding mechanism of the sensor is also more compact compared to previous designs, permitting access to uneven surfaces of the subjects. With the help of the articulated probe and a patient chair, we are able to perform co-registered imaging on human subjects on both upper and lower extremities while they are at rest positions. An increase in performance characteristics is also achieved. Patients with skin diseases are currently being recruited to test its clinical feasibility.

  14. Programmable oligonucleotide probes design and applications for in situ and in vivo RNA imaging in cells

    NASA Astrophysics Data System (ADS)

    Cheglakov, Zoya

    Unequal spreading of mRNA is a frequent experience observed in varied cell lines. The study of cellular processes dynamics and precise localization of mRNAs offers a vital toolbox to target specific proteins in precise cytoplasmic areas and provides a convenient instrument to uncover their mechanisms and functions. Latest methodological innovations have allowed imaging of a single mRNA molecule in situ and in vivo. Today, Fluorescent In Situ Hybridization (FISH) methods allow the studying of mRNA expression and offer a vital toolbox for accurate biological models. Studies enable analysis of the dynamics of an individual mRNA, have uncovered the multiplex RNA transport systems. With all current approaches, a single mRNA tracking in the mammalian cells is still challenging. This thesis describes mRNA detection methods based on programmable fluorophore-labeled DNA structures complimentary to native targets providing an accurate mRNA imaging in mammalian cells. First method represents beta-actin (ACTB) transcripts in situ detection in human cells, the technique strategy is based on programmable DNA probes, amplified by rolling circle amplification (RCA). The method reports precise localization of molecule of interest with an accuracy of a single-cell. Visualization and localization of specific endogenous mRNA molecules in real-time in vivo has the promising to innovate cellular biology studies, medical analysis and to provide a vital toolbox in drugs invention area. Second method described in this thesis represents miR-21 miRNA detection within a single live-cell resolution. The method using fluorophore-labeled short synthetic DNAs probes forming a stem-loop shape and generating Fluorescent Resonance Energy Transfer (FRET) as a result of target-probes hybridization. Catalytic nucleic acid (DNAzymes) probes are cooperative tool for precise detection of different mRNA targets. With assistance of a complementary fluorophore-quencher labeled substrate, the DNAzymes provide

  15. In vivo three-dimensional photoacoustic imaging based on a clinical matrix array ultrasound probe

    NASA Astrophysics Data System (ADS)

    Wang, Yu; Erpelding, Todd N.; Jankovic, Ladislav; Guo, Zijian; Robert, Jean-Luc; David, Guillaume; Wang, Lihong V.

    2012-06-01

    We present an integrated photoacoustic and ultrasonic three-dimensional (3-D) volumetric imaging system based on a two-dimensional (2-D) matrix array ultrasound probe. A wavelength-tunable dye laser pumped by a Q-switched Nd:YAG laser serves as the light source and a modified commercial ultrasound imaging system (iU22, Philips Healthcare) with a 2-D array transducer (X7-2, Philips Healthcare) detects both the pulse-echo ultrasound and photoacoustic signals. A multichannel data acquisition system acquires the RF channel data. The imaging system enables rendering of co-registered 3-D ultrasound and photoacoustic images without mechanical scanning. The resolution along the azimuth, elevation, and axial direction are measured to be 0.69, 0.90 and 0.84 mm for photoacoustic imaging. In vivo 3-D photoacoustic mapping of the sentinel lymph node was demonstrated in a rat model using methylene blue dye. These results highlight the clinical potential of 3-D PA imaging for identification of sentinel lymph nodes for cancer staging in humans.

  16. Targeted imaging of cancer by fluorocoxib C, a near-infrared cyclooxygenase-2 probe

    NASA Astrophysics Data System (ADS)

    Uddin, Md. Jashim; Crews, Brenda C.; Ghebreselasie, Kebreab; Daniel, Cristina K.; Kingsley, Philip J.; Xu, Shu; Marnett, Lawrence J.

    2015-05-01

    Cyclooxygenase-2 (COX-2) is a promising target for the imaging of cancer in a range of diagnostic and therapeutic settings. We report a near-infrared COX-2-targeted probe, fluorocoxib C (FC), for visualization of solid tumors by optical imaging. FC exhibits selective and potent COX-2 inhibition in both purified protein and human cancer cell lines. In vivo optical imaging shows selective accumulation of FC in COX-2-overexpressing human tumor xenografts [1483 head and neck squamous cell carcinoma (HNSCC)] implanted in nude mice, while minimal uptake is detectable in COX-2-negative tumor xenografts (HCT116) or 1483 HNSCC xenografts preblocked with the COX-2-selective inhibitor celecoxib. Time course imaging studies conducted from 3 h to 7-day post-FC injection revealed a marked reduction in nonspecific fluorescent signals with retention of fluorescence in 1483 HNSCC tumors. Thus, use of FC in a delayed imaging protocol offers an approach to improve imaging signal-to-noise that should improve cancer detection in multiple preclinical and clinical settings.

  17. Forward-viewing photoacoustic imaging probe with bundled ultra-thin hollow optical fibers

    NASA Astrophysics Data System (ADS)

    Seki, A.; Iwai, K.; Katagiri, T.; Matsuura, Y.

    2016-07-01

    A photoacoustic imaging system composed of a flexible bundle of thin hollow-optical fibers is proposed for endoscopic diagnosis. In this system, a bundle of 127 hollow-optical fibers with an inner diameter of 100 μm was fabricated. The total diameter of the bundle was 2.1 mm, and the minimum bending radius was around 10 mm. Owing to the small numerical aperture of hollow optical fibers, a high resolution image was obtained without using a lens array at the distal end. In the imaging system, the hollow fibers in the bundle were aligned at the input end, so the hollow fibers were sequentially excited by linearly scanning the laser beam at the input end. Photoacoustic imaging systems consisting of the bundled fibers for excitation of acoustic wave and piezoelectric probes for detection of photoacoustic signals were built. By using the systems, photoacoustic images of blood vessels in the ovarian membrane of fish were taken to test the feasibility of the system. As a result, photoacoustic images of the vessel were successfully obtained with a laser fluence of around 6.6 mJ cm-2.

  18. Forward-viewing photoacoustic imaging probe with bundled ultra-thin hollow optical fibers

    NASA Astrophysics Data System (ADS)

    Seki, A.; Iwai, K.; Katagiri, T.; Matsuura, Y.

    2016-07-01

    A photoacoustic imaging system composed of a flexible bundle of thin hollow-optical fibers is proposed for endoscopic diagnosis. In this system, a bundle of 127 hollow-optical fibers with an inner diameter of 100 μm was fabricated. The total diameter of the bundle was 2.1 mm, and the minimum bending radius was around 10 mm. Owing to the small numerical aperture of hollow optical fibers, a high resolution image was obtained without using a lens array at the distal end. In the imaging system, the hollow fibers in the bundle were aligned at the input end, so the hollow fibers were sequentially excited by linearly scanning the laser beam at the input end. Photoacoustic imaging systems consisting of the bundled fibers for excitation of acoustic wave and piezoelectric probes for detection of photoacoustic signals were built. By using the systems, photoacoustic images of blood vessels in the ovarian membrane of fish were taken to test the feasibility of the system. As a result, photoacoustic images of the vessel were successfully obtained with a laser fluence of around 6.6 mJ cm‑2.

  19. Noninvasive imaging of multiple myeloma using near infrared fluorescent molecular probe

    NASA Astrophysics Data System (ADS)

    Hathi, Deep; Zhou, Haiying; Bollerman-Nowlis, Alex; Shokeen, Monica; Akers, Walter J.

    2016-03-01

    Multiple myeloma is a plasma cell malignancy characterized by monoclonal gammopathy and osteolytic bone lesions. Multiple myeloma is most commonly diagnosed in late disease stages, presenting with pathologic fracture. Early diagnosis and monitoring of disease status may improve quality of life and long-term survival for multiple myeloma patients from what is now a devastating and fatal disease. We have developed a near-infrared targeted fluorescent molecular probe with high affinity to the α4β1 integrin receptor (VLA-4)overexpressed by a majority of multiple myeloma cells as a non-radioactive analog to PET/CT tracer currently being developed for human diagnostics. A near-infrared dye that emits about 700 nm was conjugated to a high affinity peptidomimmetic. Binding affinity and specificity for multiple myeloma cells was investigated in vitro by tissue staining and flow cytometry. After demonstration of sensitivity and specificity, preclinical optical imaging studies were performed to evaluate tumor specificity in murine subcutaneous and metastatic multiple myeloma models. The VLA-4-targeted molecular probe showed high affinity for subcutaneous MM tumor xenografts. Importantly, tumor cells specific accumulation in the bone marrow of metastatic multiple myeloma correlated with GFP signal from transfected cells. Ex vivo flow cytometry of tumor tissue and bone marrow further corroborated in vivo imaging data, demonstrating the specificity of the novel agent and potential for quantitative imaging of multiple myeloma burden in these models.

  20. Tension promoted circular probe for highly selective microRNA detection and imaging.

    PubMed

    Tang, Yaqin; Wang, Tingting; Chen, Ming; He, Xiao; Qu, Xiaohuan; Feng, Xuli

    2016-11-15

    The crucial role of miRNA in cell regulation and its connection with diverse human cancers as a tumor suppressor or an oncogenic fragment poses great demand for an accurate and rapid approach for highly efficient miRNA detection and imaging in live cells. However, the ability to selectively detect and image miRNA remains a significant challenge in biomedical fields. Herein, a sealed circular probe (CP) has been prepared with copper free click ligation. The big tension force of the ring structure greatly increases the sequence recognition specificity. Toehold initiated strand displacement of CP further amplify the selectivity for miRNA determination. Impressively, the different site of single base mismatch could even be discriminated. More importantly, CP was successfully applied for imaging endogenous miRNA expression in live cells. We believe that this new probe would find wide application in profiling of endogenous miRNA and be potential candidate method for helping us diagnosing miRNA related diseases. PMID:27162146

  1. Evaluation of Potential PET Imaging Probes for the Orexin 2 Receptors

    PubMed Central

    Wang, Changning; Wilson, Colin M.; Moseley, Christian K.; Carlin, Stephen M.; Hsu, Shirley; Arabasz, Grae; Schroeder, Frederick A.; Sander, Christin Y.; Hooker, Jacob M.

    2013-01-01

    A wide range of central nervous system (CNS) disorders, particularly those related to sleep, are associated with the abnormal function of orexin (OX) receptors. Several orexin receptor antagonists have been reported in recent years, but currently there are no imaging tools to probe the density and function of orexin receptors in vivo. To date there are no published data on the pharmacokinetics (PK) and accumulation of some lead orexin receptor antagonists. Evaluation of CNS pharmacokinetics in the pursuit of positron emission tomography (PET) radiotracer development could be used to elucidate the association of orexin receptors with diseases and to facilitate the drug discovery and development. To this end, we designed and evaluated carbon-11 labeled compounds based on diazepane orexin receptor antagonists previously described. One of the synthesized compounds, [11C]CW4 showed high brain uptake in rats and further evaluated in non-human primate (NHP) using PET-MR imaging. PET scans performed in a baboon showed appropriate early brain uptake for consideration as a radiotracer. However, [11C]CW4 exhibited fast kinetics and high nonspecific binding, as determined after co-administration of [11C]CW4 and unlabeled CW4. These properties indicate that [11C]CW4 has excellent brain penetrance and could be used as a lead compound for developing new CNS-penetrant PET imaging probes of orexin receptors. PMID:23953751

  2. Synthetic aperture microwave imaging with active probing for fusion plasma diagnostics

    SciTech Connect

    Shevchenko, Vladimir F.; Freethy, Simon J.; Huang, Billy K.

    2014-08-21

    A Synthetic Aperture Microwave Imaging (SAMI) system has been designed and built to obtain 2-D images at several frequencies from fusion plasmas. SAMI uses a phased array of linearly polarised antennas. The array configuration has been optimised to achieve maximum synthetic aperture beam efficiency. The signals received by antennas are down-converted to the intermediate frequency range and then recorded in a full vector form. Full vector signals allow beam focusing and image reconstruction in both real time and a post-processing mode. SAMI can scan over 16 pre-programmed frequencies in the range of 10-35GHz with a switching time of 300ns. The system operates in 2 different modes simultaneously: both a 'passive' imaging of plasma emission and also an 'active' imaging of the back-scattered signal of the radiation launched by one of the antennas from the same array. This second mode is similar to so-called Doppler backscattering (DBS) reflectometry with 2-D resolution of the propagation velocity of turbulent structures. Both modes of operation show good performance in fusion plasma experiments on Mega Amp Spherical Tokamak (MAST). We have obtained the first ever 2-D images of BXO mode conversion windows. With active probing, first ever turbulence velocity maps have been obtained. We present an overview of the diagnostic and discuss recent results. In contrast to quasi-optical microwave imaging systems SAMI requires neither big aperture viewing ports nor large 2-D detector arrays to achieve the desired imaging resolution. The number of effective 'pixels' of the synthesized image is proportional to the number of receiving antennas squared. Thus only a small number of optimised antennas is sufficient for the majority of applications. Possible implementation of SAMI on ITERand DEMO is discussed.

  3. Multiplane Transthoracic Echocardiography: Image Orientation, Anatomic Correlation, and Clinical Experience with a Prototype Phased Array Multiplane Surface Probe.

    PubMed

    Yao, Jiefen; Cao, Qi-Ling; Pandian, Natesa G.; Sugeng, Lissa; Marx, Gerald; Masani, Navroz; Yeung, Hubert

    1997-11-01

    Multiplane transthoracic echocardiography provides numerous sequential images by rotation of the transducer imaging array through 180 degrees with the surface probe at a fixed site. We explored the potential of this new technique with a 3.7/5-MHz prototype multiplane transthoracic probe. Echoanatomic correlations were first examined in ten explanted hearts. The transducer was then applied in 30 normal humans at transthoracic acoustic windows to determine the imaging planes available. Use of this probe in 76 patients with various cardiac disorders indicated that this probe eases the procedure of transthoracic echocardiographic examination, provides incremental information for improved delineation and understanding of cardiac pathology, and yields many novel insights to echocardiographic interpretation. Multiplane transthoracic echocardiography appears to expand the versatility of transthoracic two-dimensional echocardiography.

  4. Imaging of a soft, weakly adsorbing, living cell with a colloid probe tapping atomic force microscope technique.

    PubMed

    McNamee, Cathy E; Pyo, Nayoung; Tanaka, Saaya; Kanda, Yoichi; Higashitani, Ko

    2006-01-15

    Here, we propose a new method to improve the atomic force microscopy (AFM) image resolution of soft samples, such as cells, in liquid. Attaching a colloid probe to a cantilever was seen improve the image resolution of a living cell in a physiological buffer solution, obtained by the normal tapping mode, when compared to an image obtained using a regular cantilever tip. This may be due to the averaging out of the cantilever tip swinging caused by the visco-elasticity of the cell. The resolution was best, when silica spheres with a 3.3 microm diameter were attached. Although larger spheres gave a resolution better than a bare cantilever tip, their resolution was less than that obtained for the 3.3 microm diameter silica colloid. This dependency of the image resolution on the colloid probe size may be a result of the increased macroscopic van der Waals attraction between the cell and probe, the decreased repulsive force dependence on the cantilever probe radius, and the decrease in resolution due to the increased probe size. The size of the colloid probe, which should be attached to the cantilever to give the best image resolution, would be the one that optimises the combined result of these facts. PMID:16406494

  5. Gold nanoparticles-based SPECT/CT imaging probe targeting for vulnerable atherosclerosis plaques.

    PubMed

    Li, Xiao; Wang, Cong; Tan, Hui; Cheng, Leilei; Liu, Guobing; Yang, Yi; Zhao, Yanzhao; Zhang, Yiqiu; Li, Yanli; Zhang, Chunfu; Xiu, Yan; Cheng, Dengfeng; Shi, Hongcheng

    2016-11-01

    In order to realize accurate localization and precise evaluation of vulnerability of atherosclerotic plaques via dual-modal imaging, gold nanoparticles (GNPs) were firstly caped with a thin amino-PEGs cover and then conjugated with the targeting molecular Annexin V and radionuclide Tc-99m simultaneously to form SPECT/CT imaging probe targeting apoptotic macrophages. The as-synthesized (99m)Tc-GNPs-Annexin V was with uniform size (30.2 ± 2.9 nm) and high labeling rate (98.9 ± 0.5%) and stability. Targeting ability of Annexin V for apoptotic macrophages was kept and enhanced. For macrophages with 30% apoptosis, cellular uptakes of 3.52 ± 0.35% for (99m)Tc-GNPs-Annexin V, 2.41 ± 0.53% for (99m)Tc-GNPs and 1.68 ± 0.36% for (99m)Tc-Annexin V were achieved after 2 h incubation. ApoE knock out mice with high fat diet-induced atherosclerosis were scanned via (99m)Tc-GNPs-Annexin V SPECT/CT. With the introduction of targeting molecules, imaging probe was more efficient in accumulating in apoptotic macrophages. In practical evaluation, CT helps to restrict the lesions depiction more accurately, meanwhile, SPECT imaging intensity correlated with pathological changes tightly. In conclusion, Annexin V-modified hybrid gold nanoparticles were successfully synthesized, and this imaging system helped to better localize and diagnose those vulnerable AS plaques via specific targeting the apoptotic macrophages.

  6. Gold nanoparticles-based SPECT/CT imaging probe targeting for vulnerable atherosclerosis plaques.

    PubMed

    Li, Xiao; Wang, Cong; Tan, Hui; Cheng, Leilei; Liu, Guobing; Yang, Yi; Zhao, Yanzhao; Zhang, Yiqiu; Li, Yanli; Zhang, Chunfu; Xiu, Yan; Cheng, Dengfeng; Shi, Hongcheng

    2016-11-01

    In order to realize accurate localization and precise evaluation of vulnerability of atherosclerotic plaques via dual-modal imaging, gold nanoparticles (GNPs) were firstly caped with a thin amino-PEGs cover and then conjugated with the targeting molecular Annexin V and radionuclide Tc-99m simultaneously to form SPECT/CT imaging probe targeting apoptotic macrophages. The as-synthesized (99m)Tc-GNPs-Annexin V was with uniform size (30.2 ± 2.9 nm) and high labeling rate (98.9 ± 0.5%) and stability. Targeting ability of Annexin V for apoptotic macrophages was kept and enhanced. For macrophages with 30% apoptosis, cellular uptakes of 3.52 ± 0.35% for (99m)Tc-GNPs-Annexin V, 2.41 ± 0.53% for (99m)Tc-GNPs and 1.68 ± 0.36% for (99m)Tc-Annexin V were achieved after 2 h incubation. ApoE knock out mice with high fat diet-induced atherosclerosis were scanned via (99m)Tc-GNPs-Annexin V SPECT/CT. With the introduction of targeting molecules, imaging probe was more efficient in accumulating in apoptotic macrophages. In practical evaluation, CT helps to restrict the lesions depiction more accurately, meanwhile, SPECT imaging intensity correlated with pathological changes tightly. In conclusion, Annexin V-modified hybrid gold nanoparticles were successfully synthesized, and this imaging system helped to better localize and diagnose those vulnerable AS plaques via specific targeting the apoptotic macrophages. PMID:27619241

  7. Pump-probe imaging of laser-induced periodic surface structures after ultrafast irradiation of Si

    SciTech Connect

    Murphy, Ryan D.; Torralva, Ben; Adams, David P.; Yalisove, Steven M.

    2013-09-30

    Ultrafast pump-probe microscopy has been used to investigate laser-induced periodic surface structure (LIPSS) formation on polished Si surfaces. A crater forms on the surface after irradiation by a 150 fs laser pulse, and a second, subsequent pulse forms LIPSS within the crater. Sequentially delayed images show that LIPSS with a periodicity slightly less than the fundamental laser wavelength of 780 nm appear on Si surfaces ∼50 ps after arrival of the second pump laser pulse, well after the onset of melting. LIPSS are observed on the same timescale as material removal, suggesting that their formation involves material ejection.

  8. Multimodality imaging probe for positron emission tomography and fluorescence imaging studies.

    PubMed

    Pandey, Suresh K; Kaur, Jasmeet; Easwaramoorthy, Balu; Shah, Ankur; Coleman, Robert; Mukherjee, Jogeshwar

    2014-01-01

    Our goal is to develop multimodality imaging agents for use in cell tracking studies by positron emission tomography (PET) and optical imaging (OI). For this purpose, bovine serum albumin (BSA) was complexed with biotin (histologic studies), 5(6)-carboxyfluorescein, succinimidyl ester (FAM SE) (OI studies), and diethylenetriamine pentaacetic acid (DTPA) for chelating gallium 68 (PET studies). For synthesis of BSA-biotin-FAM-DTPA, BSA was coupled to (+)-biotin N-hydroxysuccinimide ester (biotin-NHSI). BSA-biotin was treated with DTPA-anhydride and biotin-BSA-DTPA was reacted with FAM. The biotin-BSA-DTPA-FAM was reacted with gallium chloride 3 to 5 mCi eluted from the generator using 0.1 N HCl and was passed through basic resin (AG 11 A8) and 150 μCi (100 μL, pH 7-8) was incubated with 0.1 mg of FAM conjugate (100 μL) at room temperature for 15 minutes to give 68Ga-BSA-biotin-DTPA-FAM. A shaved C57 black mouse was injected with FAM conjugate (50 μL) at one flank and FAM-68Ga (50 μL, 30 μCi) at the other. Immediately after injection, the mouse was placed in a fluorescence imaging system (Kodak In-Vivo F, Bruker Biospin Co., Woodbridge, CT) and imaged (λex: 465 nm, λem: 535 nm, time: 8 seconds, Xenon Light Source, Kodak). The same mouse was then placed under an Inveon microPET scanner (Siemens Medical Solutions, Knoxville, TN) injected (intravenously) with 25 μCi of 18F and after a half-hour (to allow sufficient bone uptake) was imaged for 30 minutes. Molecular weight determined using matrix-associated laser desorption ionization (MALDI) for the BSA sample was 66,485 Da and for biotin-BSA was 67,116 Da, indicating two biotin moieties per BSA molecule; for biotin-BSA-DTPA was 81,584 Da, indicating an average of 30 DTPA moieties per BSA molecule; and for FAM conjugate was 82,383 Da, indicating an average of 1.7 fluorescent moieties per BSA molecule. Fluorescence imaging clearly showed localization of FAM conjugate and FAM-68Ga at respective flanks of the mouse

  9. Attitude and angular rates of planetary probes during atmospheric descent: Implications for imaging

    NASA Astrophysics Data System (ADS)

    Lorenz, Ralph D.

    2010-04-01

    Attitude dynamics data from planetary missions are reviewed to obtain a zeroth-order expectation on the tilts and angular rates to be expected on atmospheric probes during descent: these rates are a strong driver on descent imager design. While recent Mars missions have been equipped with capable inertial measurements, attitude measurements for missions to other planetary bodies are rather limited but some angular motion estimates can be derived from accelerometer, Doppler or other data. It is found that robust camera designs should tolerate motions of the order of 20-40°/s, encountered by Mars Pathfinder, Pioneer Venus, Venera and the high speed part of the Huygens descent on Titan. Under good conditions, parachute-stabilized probes can experience rates of 1-5°/s, seen by the Mars Exploration Rovers and Viking, Galileo at Jupiter, and the slow speed parts of the Huygens descent. In the lowest 20 km of the descent on Titan, the Huygens probe was within 2° of vertical over 95% of the time. Some factors influencing these motions are discussed.

  10. Ultrafast dynamics in helium nanodroplets probed by femtosecond time-resolved EUV photoelectron imaging

    SciTech Connect

    Kornilov, Oleg; Wang, Chia C.; Buenermann, Oliver; Healy, Andrew T.; Leonard, Mathew; Peng, Chunte; Leone, Stephen R.; Neumark, Daniel M.; Gessner, Oliver

    2010-07-09

    The dynamics of electronically excited helium nanodroplets are studied by femtosecond time-resolved photoelectron imaging. EUV excitation into a broad absorption band centered around 23.8 eV leads to an indirect photoemission process that generates ultraslow photoelectrons. A 1.58 eV probe pulse transiently depletes the indirect photoemission signal for pump-probe time delays <200 fs and enhances the signal beyond this delay. The depletion is due to suppression of the indirect ionization process by the probe photon, which generates a broad, isotropically emitted photoelectron band. Similar time scales in the decay of the high energy photoelectron signal and the enhancement of the indirect photoemission signal suggest an internal relaxation process that populates states in the range of a lower energy droplet absorption band located just below the droplet ionization potential (IP {approx} 23.0 eV). A nearly 70% enhancement of the ultraslow photoelectron signal indicates that interband relaxation plays a more dominant role for the droplet de-excitation mechanism than photoemission.

  11. Library synthesis, screening, and discovery of modified Zinc(II)-Bis(dipicolylamine) probe for enhanced molecular imaging of cell death.

    PubMed

    Plaunt, Adam J; Harmatys, Kara M; Wolter, William R; Suckow, Mark A; Smith, Bradley D

    2014-04-16

    Zinc(II)-bis(dipicolylamine) (Zn-BDPA) coordination complexes selectively target the surfaces of dead and dying mammalian cells, and they have promise as molecular probes for imaging cell death. A necessary step toward eventual clinical imaging applications is the development of next-generation Zn-BDPA complexes with enhanced affinity for the cell death membrane biomarker, phosphatidylserine (PS). This study employed an iterative cycle of library synthesis and screening, using a novel rapid equilibrium dialysis assay, to discover a modified Zn-BDPA structure with high and selective affinity for vesicles containing PS. The lead structure was converted into a deep-red fluorescent probe and its targeting and imaging performance was compared with an unmodified control Zn-BDPA probe. The evaluation process included a series of FRET-based vesicle titration studies, cell microscopy experiments, and rat tumor biodistribution measurements. In all cases, the modified probe exhibited comparatively higher affinity and selectivity for the target membranes of dead and dying cells. The results show that this next-generation deep-red fluorescent Zn-BDPA probe is well suited for preclinical molecular imaging of cell death in cell cultures and animal models. Furthermore, it should be possible to substitute the deep-red fluorophore with alternative reporter groups that enable clinically useful, deep-tissue imaging modalities, such as MRI and nuclear imaging.

  12. Cysteine cathepsins: their role in tumor progression and recent trends in the development of imaging probes

    PubMed Central

    Löser, Reik; Pietzsch, Jens

    2015-01-01

    Papain-like cysteine proteases bear an enormous potential as drug discovery targets for both infectious and systemic human diseases. The considerable progress in this field over the last two decades has also raised interest in the visualization of these enzymes in their native context, especially with regard to tumor imaging. After a short introduction to structure and general functions of human cysteine cathepsins, we highlight their importance for drug discovery and development and provide a critical update on the current state of knowledge toward their involvement in tumor progression, with a special emphasis on their role in therapy response. In accordance with a radiopharmaceutical point of view, the main focus of this review article will be the discussion of recently developed fluorescence and radiotracer-based imaging agents together with related molecular probes. PMID:26157794

  13. Scanning Hall Probe Imaging of ErNi2B2C

    SciTech Connect

    Bluhm, Hendrik; Sebastian, Suchitra; Guikema, Janice W.; Fisher, I.R.; Moler, Kathryn A.; /Stanford U., Appl. Phys. Dept.

    2005-12-02

    We report scanning Hall probe imaging of ErNi{sub 2}B{sub 2}C in the superconducting, antiferromagnetic, and weakly ferromagnetic regimes in magnetic fields up to 20 Oe, well below H{sub c1}, with two results. First, imaging isolated vortices shows that they spontaneously rearrange on cooling through the antiferromagnetic transition temperature T{sub N} = 6 K to pin on twin boundaries, forming a striped pattern. Second, a weak, random magnetic signal appears in the ferromagnetic phase below T{sub WFM} = 2.3 K, and no spontaneous vortex lattice is present down to 1.9 K. We conclude that ferromagnetism coexists with superconductivity either by forming small ferromagnetic domains or with oscillatory variation of the magnetization on sub-penetration depth length scales.

  14. Cysteine cathepsins: their role in tumor progression and recent trends in the development of imaging probes

    NASA Astrophysics Data System (ADS)

    Löser, Reik; Pietzsch, Jens

    2015-06-01

    Papain-like cysteine proteases bear an enormous potential as drug discovery targets for both infectious and systemic human diseases. The considerable progress in this field over the last two decades has also raised interest in the visualization of these enzymes in their native context, especially with regard to tumor imaging. After a short introduction to structure and general functions of human cysteine cathepsins, we highlight their importance for drug discovery and development and provide a critical update on the current state of knowledge towards their involvement in tumor progression, with a special emphasis on their role in therapy response. In accordance with a radiopharmaceutical point of view, the main focus of this review article will be the discussion of recently developed fluorescence and radiotracer-based imaging agents together with related molecular probes.

  15. Mn-doped near-infrared quantum dots as multimodal targeted probes for pancreatic cancer imaging.

    PubMed

    Yong, Ken-Tye

    2009-01-01

    This work presents a novel approach to producing manganese (Mn)-doped quantum dots (Mnd-QDs) emitting in the near-infrared (NIR). Surface functionalization of Mnd-QDs with lysine makes them stably disperse in aqueous media and able to conjugate with targeting molecules. The nanoparticles were structurally and compositionally characterized and maintained a high photoluminescence quantum yield and displayed paramagnetism in water. The receptor-mediated delivery of bioconjugated Mnd-QDs into pancreatic cancer cells was demonstrated using the confocal microscopy technique. Cytotoxicity of Mnd-QDs on live cells has been evaluated. The NIR-emitting characteristic of the QDs has been exploited to acquire whole animal body imaging with high contrast signals. In addition, histological and blood analysis of mice have revealed that no long-term toxic effects arise from MnD-QDs. These studies suggest multimodal Mnd-QDs have the potentials as probes for early pancreatic cancer imaging and detection.

  16. Simultaneous imaging and restoration of cell function using cell permeable peptide probe.

    PubMed

    Suh, Jin Sook; Lee, Jue Yeon; Lee, Gene; Chung, Chong Pyoung; Park, Yoon Jeong

    2014-08-01

    Targeting tissues/cells using probing materials to detect diseases such as cancer and inflammatory disease has been attempted with some success. Most of the molecular targets used in diagnosis and therapy were identified through the discovery of intracellular signaling pathways. Among intracellular signaling processes, the ubiquitination of proteins, and thereby their proteasomal degradation, is important because it plays a role in most diseases involving alterations to a component of the ubiquitination system, particularly E3 ligases, which have selective target-binding affinity and are key to the success of regulating the disorder. The regulation and monitoring of E3 ligases can be achieved using peptides containing protein-protein binding motifs. We generated a human protein-derived peptide that could target Smurf1, a member of the E3 ligase family, by competitively binding to osteo-Smads. To effectively deliver it into cells, the peptide was further modified with a cell-penetrating peptide. The peptide contains two fluorescent dyes: fluorescein isothiocyanate (FITC; absorbance/emission wavelengths: 495/519 nm) as a fluorophore and black hole quencher-1 (BHQ-1) as a fluorescence quencher. When the target Smurf1 combined with complementary sequences in the peptide probe, the distance between the fluorophore and BHQ-1 increased via a conformational change, resulting in the recovery of the fluorescence signal. Simultaneously, the degradation of Smad1/5/8 was blocked by the binding of the peptide probe to Smurf1, leading to the potentiation of the osteogenic pathway, which was reflected by an increase in the expression of osteoinductive genes, such as alkaline phosphatase and osteocalcin. Possible future applications of the peptide probe include its integration into imaging tools for the diagnosis of Smurf1-overexpressing diseases. PMID:24831974

  17. Reaction-Based Probes for Imaging Mobile Zinc in Live Cells and Tissues

    PubMed Central

    2015-01-01

    Chelatable, or mobile, forms of zinc play critical signaling roles in numerous biological processes. Elucidating the action of mobile Zn(II) in complex biological environments requires sensitive tools for visualizing, tracking, and manipulating Zn(II) ions. A large toolbox of synthetic photoinduced electron transfer (PET)-based fluorescent Zn(II) sensors are available, but the applicability of many of these probes is limited by poor zinc sensitivity and low dynamic ranges owing to proton interference. We present here a general approach for acetylating PET-based probes containing a variety of fluorophores and zinc-binding units. The new sensors provide substantially improved zinc sensitivity and allow for incubation of live cells and tissue slices with nM probe concentrations, a significant improvement compared to the μM concentrations that are typically required for a measurable fluorescence signal. Acetylation effectively reduces or completely quenches background fluorescence in the metal-free sensor. Binding of Zn(II) selectively and quickly mediates hydrolytic cleavage of the acetyl groups, providing a large fluorescence response. An acetylated blue coumarin-based sensor was used to carry out detailed analyses of metal binding and metal-promoted acetyl hydrolysis. Acetylated benzoresorufin-based red-emitting probes with different zinc-binding sites are effective for sensing Zn(II) ions in live cells when applied at low concentrations (∼50–100 nM). We used green diacetylated Zinpyr1 (DA-ZP1) to image endogenous mobile Zn(II) in the molecular layer of mouse dorsal cochlear nucleus (DCN), confirming that acetylation is a suitable approach for preparing sensors that are highly specific and sensitive to mobile zinc in biological systems. PMID:26878065

  18. Preclinical Study on GRPR-Targeted (68)Ga-Probes for PET Imaging of Prostate Cancer.

    PubMed

    Sun, Yao; Ma, Xiaowei; Zhang, Zhe; Sun, Ziyan; Loft, Mathias; Ding, Bingbing; Liu, Changhao; Xu, Liying; Yang, Meng; Jiang, Yuxin; Liu, Jianfeng; Xiao, Yuling; Cheng, Zhen; Hong, Xuechuan

    2016-08-17

    Gastrin-releasing peptide receptor (GRPR) targeted positron emission tomography (PET) is a highly promising approach for imaging of prostate cancer (PCa) in small animal models and patients. Developing a GRPR-targeted PET probe with excellent in vivo performance such as high tumor uptake, high contrast, and optimal pharmacokinetics is still very challenging. Herein, a novel bombesin (BBN) analogue (named SCH1) based on JMV594 peptide modified with an 8-amino octanoic acid spacer (AOC) was thus designed and conjugated with the metal chelator 1,4,7-triazacyclononane,1-glutaric acid-4,7-acetic acid (NODAGA). The resulting NODAGA-SCH1 was then radiolabeled with (68)Ga and evaluated for PET imaging of PCa. Compared with (68)Ga-NODAGA-JMV594 probe, (68)Ga-NODAGA-SCH1 exhibited excellent PET/CT imaging properties on PC-3 tumor-bearing nude mice, such as high tumor uptake (5.80 ± 0.42 vs 3.78 ± 0.28%ID/g, 2 h) and high tumor/muscle contrast (16.6 ± 1.50 vs 8.42 ± 0.61%ID/g, 2 h). Importantly, biodistribution data indicated a relatively similar accumulation of (68)Ga-NODAGA-SCH1 was observed in the liver (4.21 ± 0.42%ID/g) and kidney (3.41 ± 0.46%ID/g) suggesting that the clearance is through both the kidney and the liver. Overall, (68)Ga-NODAGA-SCH1 showed promising in vivo properties and is a promising candidate for translation into clinical PET-imaging of PCa patients.

  19. A novel indocyanine green nanoparticle probe for non invasive fluorescence imaging in vivo

    NASA Astrophysics Data System (ADS)

    Navarro, Fabrice P.; Berger, Michel; Goutayer, Mathieu; Guillermet, Stéphanie; Josserand, Véronique; Rizo, Philippe; Vinet, Françoise; Texier, Isabelle

    2009-02-01

    Fluorescence imaging (FLI) allows the in vivo monitoring of biological events associated with disease and represents a new promising tool for drug discovery. In particular, it speeds up the development and assessment of new therapies in oncology, helps in diagnosis, and improves surgery by fluorescence-guided tumor resection. This technique is highly sensitive, non-ionizing, easy to use and relatively inexpensive. Nevertheless, the main limitation of FLI lies in the optical properties of biological tissues. Mainly because of haemoglobin and water absorption, only near-infrared (NIR) light is adapted to image tissues in depth. Using a contrasting agent absorbing and emitting in the NIR region is therefore necessary to improve the background signal ratio, and thus the image contrast. Among many commercially available NIR optical contrast agents, only indocyanine green (ICG), has been approved by the United State Food and Drug Administration (FDA) for various medical applications. However, its instability (photo-degradation, thermal-degradation and low aqueous solubility) limits its applications as a fluorescent probe for imaging purposes. In order to improve the effectiveness of ICG, we engineered ICG-doped lipid nanoparticles (LNP). In this communication, we will report the design of these novel fluorescent nanoparticle probes. These low cost nanocarriers have numerous advantages, including their high chemical stability and biocompatibility. The characterization of the optical properties of the nanoparticles entrapping ICG will also be discussed. Finally, the biodistribution in mice of ICG when delivered through nanoparticles in comparison to free ICG in solution is presented. It demonstrates the efficient accumulation of ICG-doped nanoparticles in the tumor site.

  20. Very Wide Field Imager(VWFI) for the Hubble Origins Probe(HOP)

    NASA Astrophysics Data System (ADS)

    Tsuneta, S.; Miyazaki, S.; Nakaya, H.; Yamada, T.; Iye, M.; Kaifu, N.; Taniguchi, Y.; Doi, M.; Okamura, S.; Ikeda, Y.; Takeyama, N.; Kaido, N.; Yamaguchi, K.; Norman, C.; Ford, H.; Kruk, J.; Ouchi, M.; Woodruff, R.

    2004-12-01

    High-resolution high-throughput multi-color wide-field imaging from space allows us to: (1) study origins of galaxy morphology (z=1-2); (2) to map the post-reionization universe of z=5-10; (3) to investigate the nature of dark energy through an efficient search for distant type Ia SNe; and (4) to map the distribution of dark matter and to measure cosmological parameters with weak gravitational lensing. These science drivers can be carried out by the Very Wide Field Imager (VWFI) aboard the Hubble Origins Probe (HOP) with the other onboard science instruments COS and WFC3. VWFI consists of > 40 2K x 2K CCDs occupying >2 quadrants of the HOP focal plane with off-axis aberration corrector optics. The astigmatism corrector optics consists of a pair of simple fused-silica prisms optimized and dedicated to each CCD. The FOV of VWFI is >170 square-arcmin, and the HOP OTA with the corrector delivers stable and high Strehl-ratio images with a 0.05 arcsec CCD pixel size over the wide field of view. CCDs are cooled down to -80 degree C with a mechanical cooling system and an external dedicated radiator. The fully-depleted CCDs to be provided by Hamamatsu Photonics have a demonstrated capability of high quantum efficiency approx. 0.7 at 1 micron. The very high efficiency at red wavelengths makes VWFI exceptionally qualified to pursue the above science drivers. Multiple optimized filters either allocated to each CCDs or with the mechanical filter wheels allow multi-color imaging. VWFI is currently being studied with US-Japan working group under the auspices of the NASA Origins Probes Study. VWFI is expected to be primarily provided by Japan.

  1. Preclinical Study on GRPR-Targeted (68)Ga-Probes for PET Imaging of Prostate Cancer.

    PubMed

    Sun, Yao; Ma, Xiaowei; Zhang, Zhe; Sun, Ziyan; Loft, Mathias; Ding, Bingbing; Liu, Changhao; Xu, Liying; Yang, Meng; Jiang, Yuxin; Liu, Jianfeng; Xiao, Yuling; Cheng, Zhen; Hong, Xuechuan

    2016-08-17

    Gastrin-releasing peptide receptor (GRPR) targeted positron emission tomography (PET) is a highly promising approach for imaging of prostate cancer (PCa) in small animal models and patients. Developing a GRPR-targeted PET probe with excellent in vivo performance such as high tumor uptake, high contrast, and optimal pharmacokinetics is still very challenging. Herein, a novel bombesin (BBN) analogue (named SCH1) based on JMV594 peptide modified with an 8-amino octanoic acid spacer (AOC) was thus designed and conjugated with the metal chelator 1,4,7-triazacyclononane,1-glutaric acid-4,7-acetic acid (NODAGA). The resulting NODAGA-SCH1 was then radiolabeled with (68)Ga and evaluated for PET imaging of PCa. Compared with (68)Ga-NODAGA-JMV594 probe, (68)Ga-NODAGA-SCH1 exhibited excellent PET/CT imaging properties on PC-3 tumor-bearing nude mice, such as high tumor uptake (5.80 ± 0.42 vs 3.78 ± 0.28%ID/g, 2 h) and high tumor/muscle contrast (16.6 ± 1.50 vs 8.42 ± 0.61%ID/g, 2 h). Importantly, biodistribution data indicated a relatively similar accumulation of (68)Ga-NODAGA-SCH1 was observed in the liver (4.21 ± 0.42%ID/g) and kidney (3.41 ± 0.46%ID/g) suggesting that the clearance is through both the kidney and the liver. Overall, (68)Ga-NODAGA-SCH1 showed promising in vivo properties and is a promising candidate for translation into clinical PET-imaging of PCa patients. PMID:27399868

  2. [18F]CFA as a clinically translatable probe for PET imaging of deoxycytidine kinase activity

    PubMed Central

    Kim, Woosuk; Le, Thuc M.; Wei, Liu; Poddar, Soumya; Bazzy, Jimmy; Wang, Xuemeng; Uong, Nhu T.; Abt, Evan R.; Capri, Joseph R.; Austin, Wayne R.; Van Valkenburgh, Juno S.; Steele, Dalton; Gipson, Raymond M.; Slavik, Roger; Cabebe, Anthony E.; Taechariyakul, Thotsophon; Yaghoubi, Shahriar S.; Lee, Jason T.; Sadeghi, Saman; Lavie, Arnon; Faull, Kym F.; Witte, Owen N.; Donahue, Timothy R.; Phelps, Michael E.; Herschman, Harvey R.; Herrmann, Ken; Czernin, Johannes; Radu, Caius G.

    2016-01-01

    Deoxycytidine kinase (dCK), a rate-limiting enzyme in the cytosolic deoxyribonucleoside (dN) salvage pathway, is an important therapeutic and positron emission tomography (PET) imaging target in cancer. PET probes for dCK have been developed and are effective in mice but have suboptimal specificity and sensitivity in humans. To identify a more suitable probe for clinical dCK PET imaging, we compared the selectivity of two candidate compounds—[18F]Clofarabine; 2-chloro-2′-deoxy-2′-[18F]fluoro-9-β-d-arabinofuranosyl-adenine ([18F]CFA) and 2′-deoxy-2′-[18F]fluoro-9-β-d-arabinofuranosyl-guanine ([18F]F-AraG)—for dCK and deoxyguanosine kinase (dGK), a dCK-related mitochondrial enzyme. We demonstrate that, in the tracer concentration range used for PET imaging, [18F]CFA is primarily a substrate for dCK, with minimal cross-reactivity. In contrast, [18F]F-AraG is a better substrate for dGK than for dCK. [18F]CFA accumulation in leukemia cells correlated with dCK expression and was abrogated by treatment with a dCK inhibitor. Although [18F]CFA uptake was reduced by deoxycytidine (dC) competition, this inhibition required high dC concentrations present in murine, but not human, plasma. Expression of cytidine deaminase, a dC-catabolizing enzyme, in leukemia cells both in cell culture and in mice reduced the competition between dC and [18F]CFA, leading to increased dCK-dependent probe accumulation. First-in-human, to our knowledge, [18F]CFA PET/CT studies showed probe accumulation in tissues with high dCK expression: e.g., hematopoietic bone marrow and secondary lymphoid organs. The selectivity of [18F]CFA for dCK and its favorable biodistribution in humans justify further studies to validate [18F]CFA PET as a new cancer biomarker for treatment stratification and monitoring. PMID:27035974

  3. Triboelectric sensor as self-powered signal reader for scanning probe surface topography imaging

    NASA Astrophysics Data System (ADS)

    Yu, Aifang; Chen, Libo; Chen, Xiangyu; Zhang, Aihua; Fan, Fengru; Zhan, Yan; Wang, Zhong Lin

    2015-04-01

    We report a self-powered signal reading mechanism for imaging surface topography using a triboelectric sensor (TES) without supplying an external power or light source. A membrane-structured triboelectric nanogenerator (TENG) is designed at the root of a whisker (probe); the deflection of the whisker causes the two contacting surfaces of the TENG to give an electric output current/voltage that responds to the bending degree of the whisker when it scans over a rough surface. A series of studies were carried out to characterize the performance of the TES, such as high sensitivity of 0.45 V mm-1, favorable repeating of standard deviation 8 mV, high Z-direction resolution of 18 μm, as well as lateral resolution of 250 μm by using a probe of size 11 mm in the length and 120 μm in radius. It not only can recognize the surface feature and size but also can perform a surface topography imaging in scanning mode. This work shows the potential of a TES as a self-powered tactile sensor for applications at relatively low spatial resolution.

  4. Ultrahigh relaxivity and safe probes of manganese oxide nanoparticles for in vivo imaging.

    PubMed

    Xiao, J; Tian, X M; Yang, C; Liu, P; Luo, N Q; Liang, Y; Li, H B; Chen, D H; Wang, C X; Li, L; Yang, G W

    2013-12-05

    Mn-based nanoparticles (NPs) have emerged as new class of probes for magnetic resonance imaging due to the impressive contrast ability. However, the reported Mn-based NPs possess low relaxivity and there are no immunotoxicity data regarding Mn-based NPs as contrast agents. Here, we demonstrate the ultrahigh relaxivity of water protons of 8.26 mM(-1) s(-1) from the Mn3O4 NPs synthesized by a simple and green technique, which is twice higher than that of commercial gadolinium (Gd)-based contrast agents (4.11 mM(-1) s(-1)) and the highest value reported to date for Mn-based NPs. We for the first time demonstrate these Mn3O4 NPs biocompatibilities both in vitro and in vivo are satisfactory based on systematical studies of the intrinsic toxicity including cell viability of human nasopharyngeal carcinoma cells, normal nasopharyngeal epithelium, apoptosis in cells and in vivo immunotoxicity. These findings pave the way for the practical clinical diagnosis of Mn based NPs as safe probes for in vivo imaging.

  5. Ultrahigh relaxivity and safe probes of manganese oxide nanoparticles for in vivo imaging

    NASA Astrophysics Data System (ADS)

    Xiao, J.; Tian, X. M.; Yang, C.; Liu, P.; Luo, N. Q.; Liang, Y.; Li, H. B.; Chen, D. H.; Wang, C. X.; Li, L.; Yang, G. W.

    2013-12-01

    Mn-based nanoparticles (NPs) have emerged as new class of probes for magnetic resonance imaging due to the impressive contrast ability. However, the reported Mn-based NPs possess low relaxivity and there are no immunotoxicity data regarding Mn-based NPs as contrast agents. Here, we demonstrate the ultrahigh relaxivity of water protons of 8.26 mM-1s-1 from the Mn3O4 NPs synthesized by a simple and green technique, which is twice higher than that of commercial gadolinium (Gd)-based contrast agents (4.11 mM-1s-1) and the highest value reported to date for Mn-based NPs. We for the first time demonstrate these Mn3O4 NPs biocompatibilities both in vitro and in vivo are satisfactory based on systematical studies of the intrinsic toxicity including cell viability of human nasopharyngeal carcinoma cells, normal nasopharyngeal epithelium, apoptosis in cells and in vivo immunotoxicity. These findings pave the way for the practical clinical diagnosis of Mn based NPs as safe probes for in vivo imaging.

  6. Photophysics of Fluorescent Probes for Single-Molecule Biophysics and Super-Resolution Imaging

    NASA Astrophysics Data System (ADS)

    Ha, Taekjip; Tinnefeld, Philip

    2012-05-01

    Single-molecule fluorescence spectroscopy and super-resolution microscopy are important elements of the ongoing technical revolution to reveal biochemical and cellular processes in unprecedented clarity and precision. Demands placed on the photophysical properties of the fluorophores are stringent and drive the choice of appropriate probes. Such fluorophores are not simple light bulbs of a certain color and brightness but instead have their own “personalities” regarding spectroscopic parameters, redox properties, size, water solubility, photostability, and several other factors. Here, we review the photophysics of fluorescent probes, both organic fluorophores and fluorescent proteins, used in applications such as particle tracking, single-molecule FRET, stoichiometry determination, and super-resolution imaging. Of particular interest is the thiol-induced blinking of Cy5, a curse for single-molecule biophysical studies that was later overcome using Trolox through a reducing/oxidizing system but a boon for super-resolution imaging owing to the controllable photoswitching. Understanding photophysics is critical in the design and interpretation of single-molecule experiments.

  7. Electronic dynamics in helium nanodroplets studied via femtosecond XUV pump / UV probe photoelectron imaging

    NASA Astrophysics Data System (ADS)

    Ziemkiewicz, Michael; Bacellar, Camila; Leone, Stephen; Neumark, Daniel; Gessner, Oliver

    2014-05-01

    Superfluid helium nanodroplets consisting of ~ 2 × 106 atoms are examined using femtosecond time-resolved photoelectron imaging. The droplets are excited by a 23.6(2) eV extreme ultraviolet (XUV) pulse in resonance with an electronically excited band associated largely with the 1s3p Rydberg level of free He atoms. Relaxation dynamics are monitored by ionizing transient states with a 3.2 eV probe pulse and measuring the time-dependent photoelectron kinetic energy distributions using velocity map imaging (VMI). A broad, intense signal associated with the initially excited 1s3p band (Ekin ~ 2.5 eV) appears within the experimental time resolution and decays within 190(70) fs. Concomitantly, a second photoelectron feature with kinetic energies ranging from 0 to 0.5 eV appears on a time scale of ~ 200 fs. The new feature is identified as originating from the 1s2p droplet Rydberg band, indicating the direct observation of a previously suggested interband relaxation within the droplet. This feature also decays within ~ 200 fs, likely due to intraband relaxation within the 1s2p/1s2s manifold to states which are too deeply bound to be ionized by the 3.2 eV probe pulse.

  8. Analysis of abdominal wounds made by surgical trocars using functional luminal imaging probe (FLIP) technology.

    PubMed

    McMahon, Barry P; O'Donovan, Deidre; Liao, Donghua; Zhao, Jingbo; Schiretz, Rich; Heninrich, Russell; Gregersen, Hans

    2008-09-01

    The aim was to use a novel functional luminal imaging probe for evaluation of wound defects and tissue damage resulting from the use of trocars. Following general anesthesia of 4 adult pigs, 6 different trocars were randomly inserted at preselected locations in the porcine abdominal wall. The functional luminal imaging probe was used to profile the trocar holes during bag distension from 8 axial cross-sectional area measurements. The cross-sectional areas and pressure in the bag were recorded and exported to Matlab for analysis and data display. Geometric profiles were generated, and the minimum cross-sectional area and hole length (abdominal wall thickness) were used as endpoints. Successful distensions were made in all cases. The slope of the contours increased away from the narrowest point of the hole. The slope increased more rapidly toward the inner abdominal wall than toward the outer wall. The slope of the linear trend lines for the cross-sectional area-pressure relation represents the compliance at the narrowest point in the wall. The hole length (abdominal wall thickness) could be obtained at different cross-sectional area cutoff points. A cutoff point of 300 mm(2) gave good results when compared to the length of the hole measured after the tissue was excised. This technique represents a new and straightforward way to evaluate the effects of trocars on the abdominal wall. It may also prove useful in comparing techniques and technology from different manufacturers. PMID:18757380

  9. Proton-Electron Double-Resonance Imaging of pH using phosphonated trityl probe

    PubMed Central

    Takahashi, Wataru; Bobko, Andrey A.; Dhimitruka, Ilirian; Hirata, Hiroshi; Zweier, Jay L.; Samouilov, Alexandre

    2014-01-01

    Variable Radio Frequency Proton-Electron Double-Resonance Imaging (VRF PEDRI) enables extracting a functional map from a limited number of images acquired at pre-selected EPR frequencies using specifically designed paramagnetic probes with high quality spatial resolution and short acquisition times. In this work we explored potential of VRF PEDRI for pH mapping of aqueous samples using recently synthesized pH-sensitive phosphonated trityl radical, pTR. The ratio of Overhauser enhancements measured at each pixel at two different excitation frequencies corresponding to the resonances of protonated and deprotonated forms of pTR probe allows for a pH map extraction. Long relaxation times of pTR allow for pH mapping at EPR irradiation power as low as 1.25 W during 130 s acquisition time with spatial resolution of about 1 mm. This is particularly important for in vivo applications enabling one to avoid sample overheating by reducing RF power deposition. PMID:25530673

  10. Flexible micro-OCT endobronchial probe for imaging of mucociliary transport (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Cui, Dongyao; Chu, Kengyeh K.; Unglert, Carolin I.; Ford, Tim N.; Carruth, Robert W.; Hyun, Daryl; Singh, Kanwarpal; Birket, Susan E.; Solomon, George M.; Rowe, Steve M.; Tearney, Guillermo J.

    2016-03-01

    Mucociliary clearance (MCC) plays a significant role in maintaining the health of human respiratory system by eliminating foreign particles trapped within mucus. Failure of this mechanism in diseases such as cystic fibrosis and chronic obstructive pulmonary disease (COPD) leads to airway blockage and lung infection, causing morbidity and mortality. The volume of airway mucus and the periciliary liquid encapsulating the cilia, in addition to ciliary beat frequency and velocity of mucociliary transport, are vital parameters of airway health. However, the diagnosis of disease pathogenesis and advances of novel therapeutics are hindered by the lack of tools for visualization of ciliary function in vivo. Our laboratory has previously developed a 1-µm resolution optical coherence tomography method, termed Micro-OCT, which is capable of visualizing mucociliary transport and quantitatively capturing epithelial functional metrics. We have also miniaturized Micro-OCT optics in a first-generation rigid 4mm Micro-OCT endoscope utilizing a common-path design and an apodizing prism configuration to produce an annular profile sample beam, and reported the first in vivo visualization of mucociliary transport in swine. We now demonstrate a flexible 2.5 mm Micro-OCT probe that can be inserted through the instrument channel of standard flexible bronchoscopes, allowing bronchoscopic navigation to smaller airways and greatly improving clinical utility. Longitudinal scanning over a field of view of more than 400 µm at a frame rate of 40 Hz was accomplished with a driveshaft transduced by a piezo-electric stack motor. We present characterization and imaging results from the flexible micro-OCT probe and progress towards clinical translation. The ability of the bronchoscope-compatible micro-OCT probe to image mucus clearance and epithelial function will enable studies of cystic fibrosis pathogenesis in small airways, provide diagnosis of mucociliary clearance disorders, and allow

  11. Deoxyfluoro-d-trehalose (FDTre) analogues as potential PET probes for imaging mycobacterial infection.

    PubMed

    Rundell, Sarah R; Wagar, Zachary L; Meints, Lisa M; Olson, Claire D; O'Neill, Mara K; Piligian, Brent F; Poston, Anne W; Hood, Robin J; Woodruff, Peter J; Swarts, Benjamin M

    2016-09-28

    Mycobacterium tuberculosis, the etiological agent of human tuberculosis, requires the non-mammalian disaccharide trehalose for growth and virulence. Recently, detectable trehalose analogues have gained attention as probes for studying trehalose metabolism and as potential diagnostic imaging agents for mycobacterial infections. Of particular interest are deoxy-[(18)F]fluoro-d-trehalose ((18)F-FDTre) analogues, which have been suggested as possible positron emission tomography (PET) probes for in vivo imaging of M. tuberculosis infection. Here, we report progress toward this objective, including the synthesis and conformational analysis of four non-radioactive deoxy-[(19)F]fluoro-d-trehalose ((19)F-FDTre) analogues, as well as evaluation of their uptake by M. smegmatis. The rapid synthesis and purification of several (19)F-FDTre analogues was accomplished in high yield using a one-step chemoenzymatic method. Conformational analysis of the (19)F-FDTre analogues using NMR and molecular modeling methods showed that fluorine substitution had a negligible effect on the conformation of the native disaccharide, suggesting that fluorinated analogues may be successfully recognized and processed by trehalose metabolic machinery in mycobacteria. To test this hypothesis and to evaluate a possible route for delivery of FDTre probes specifically to mycobacteria, we showed that (19)F-FDTre analogues are actively imported into M. smegmatis via the trehalose-specific transporter SugABC-LpqY. Finally, to demonstrate the applicability of these results to the efficient preparation and use of short-lived (18)F-FDTre PET radiotracers, we carried out (19)F-FDTre synthesis, purification, and administration to M. smegmatis in 1 hour. PMID:27560008

  12. In vivo reproducibility of robotic probe placement for an integrated US-CT image-guided radiation therapy system

    NASA Astrophysics Data System (ADS)

    Lediju Bell, Muyinatu A.; Sen, H. Tutkun; Iordachita, Iulian; Kazanzides, Peter; Wong, John

    2014-03-01

    Radiation therapy is used to treat cancer by delivering high-dose radiation to a pre-defined target volume. Ultrasound (US) has the potential to provide real-time, image-guidance of radiation therapy to identify when a target moves outside of the treatment volume (e.g. due to breathing), but the associated probe-induced tissue deformation causes local anatomical deviations from the treatment plan. If the US probe is placed to achieve similar tissue deformations in the CT images required for treatment planning, its presence causes streak artifacts that will interfere with treatment planning calculations. To overcome these challenges, we propose robot-assisted placement of a real ultrasound probe, followed by probe removal and replacement with a geometrically-identical, CT-compatible model probe. This work is the first to investigate in vivo deformation reproducibility with the proposed approach. A dog's prostate, liver, and pancreas were each implanted with three 2.38-mm spherical metallic markers, and the US probe was placed to visualize the implanted markers in each organ. The real and model probes were automatically removed and returned to the same position (i.e. position control), and CT images were acquired with each probe placement. The model probe was also removed and returned with the same normal force measured with the real US probe (i.e. force control). Marker positions in CT images were analyzed to determine reproducibility, and a corollary reproducibility study was performed on ex vivo tissue. In vivo results indicate that tissue deformations with the real probe were repeatable under position control for the prostate, liver, and pancreas, with median 3D reproducibility of 0.3 mm, 0.3 mm, and 1.6 mm, respectively, compared to 0.6 mm for the ex vivo tissue. For the prostate, the mean 3D tissue displacement errors between the real and model probes were 0.2 mm under position control and 0.6 mm under force control, which are both within acceptable

  13. SU-E-J-205: Monte Carlo Modeling of Ultrasound Probes for Real-Time Ultrasound Image-Guided Radiotherapy

    SciTech Connect

    Hristov, D; Schlosser, J; Bazalova, M; Chen, J

    2014-06-01

    Purpose: To quantify the effect of ultrasound (US) probe beam attenuation for radiation therapy delivered under real-time US image guidance by means of Monte Carlo (MC) simulations. Methods: MC models of two Philips US probes, an X6-1 matrix-array transducer and a C5-2 curved-array transducer, were built based on their CT images in the EGSnrc BEAMnrc and DOSXYZnrc codes. Due to the metal parts, the probes were scanned in a Tomotherapy machine with a 3.5 MV beam. Mass densities in the probes were assigned based on an electron density calibration phantom consisting of cylinders with mass densities between 0.2–8.0 g/cm{sup 3}. Beam attenuation due to the probes was measured in a solid water phantom for a 6 MV and 15 MV 15x15 cm{sup 2} beam delivered on a Varian Trilogy linear accelerator. The dose was measured with the PTW-729 ionization chamber array at two depths and compared to MC simulations. The extreme case beam attenuation expected in robotic US image guided radiotherapy for probes in upright position was quantified by means of MC simulations. Results: The 3.5 MV CT number to mass density calibration curve was found to be linear with R{sup 2} > 0.99. The maximum mass densities were 4.6 and 4.2 g/cm{sup 3} in the C5-2 and X6-1 probe, respectively. Gamma analysis of the simulated and measured doses revealed that over 98% of measurement points passed the 3%/3mm criteria for both probes and measurement depths. The extreme attenuation for probes in upright position was found to be 25% and 31% for the C5-2 and X6-1 probe, respectively, for both 6 and 15 MV beams at 10 cm depth. Conclusion: MC models of two US probes used for real-time image guidance during radiotherapy have been built. As a Result, radiotherapy treatment planning with the imaging probes in place can now be performed. J Schlosser is an employee of SoniTrack Systems, Inc. D Hristov has financial interest in SoniTrack Systems, Inc.

  14. A highly specific ferrocene-based fluorescent probe for hypochlorous acid and its application to cell imaging.

    PubMed

    Chen, Suming; Lu, Jinxin; Sun, Chengdong; Ma, Huimin

    2010-03-01

    A highly specific ferrocene-based fluorescent probe, (9-anthryl)ethenylferrocene, has been designed, synthesized and characterized for fluorescence imaging of hypochlorous acid (HOCl) in live cells. The design strategy for the probe is based on the strong quenching effect of electron-donor ferrocene on anthracene fluorescence via an intramolecular charge transfer process, and is accomplished through constructing the conjugated molecule by using a cleavable double bond as a linker. The double bond in the probe reacts selectively with HOCl rather than the other reactive oxygen species (e.g., *OH, *O(2)(-), (1)O(2), and H(2)O(2)) in pH 7.4, accompanied by more than 100-fold fluorescence enhancement. Moreover, the probe is cell membrane permeable, and its applicability has been successfully demonstrated for fluorescence imaging of HOCl in HeLa cells.

  15. Hand-held optoacoustic probe for three-dimensional imaging of human morphology and function

    NASA Astrophysics Data System (ADS)

    Deán-Ben, X. Luís.; Razansky, Daniel

    2014-03-01

    We report on a hand-held imaging probe for real-time optoacoustic visualization of deep tissues in three dimensions. The proposed solution incorporates a two-dimensional array of ultrasonic sensors densely distributed on a spherical surface, whereas illumination is performed coaxially through a cylindrical cavity in the array. Visualization of three-dimensional tomographic data at a frame rate of 10 images per second is enabled by parallel recording of 256 time-resolved signals for each individual laser pulse along with a highly efficient GPUbased real-time reconstruction. A liquid coupling medium (water), enclosed in a transparent membrane, is used to guarantee transmission of the optoacoustically generated waves to the ultrasonic detectors. Excitation at multiple wavelengths further allows imaging spectrally distinctive tissue chromophores such as oxygenated and deoxygenated haemoglobin. The performance is showcased by video-rate tracking of deep tissue vasculature and three-dimensional measurements of blood oxygenenation in a healthy human volunteer. The flexibility provided by the hand-held hardware design, combined with the real-time operation, makes the developed platform highly usable for both small animal research and clinical imaging in multiple indications, including cancer, inflammation, skin and cardiovascular diseases, diagnostics of lymphatic system and breast

  16. Scanned probe imaging of nanoscale magnetism at cryogenic temperatures with a single-spin quantum sensor

    NASA Astrophysics Data System (ADS)

    Pelliccione, Matthew; Jenkins, Alec; Ovartchaiyapong, Preeti; Reetz, Christopher; Emmanouilidou, Eve; Ni, Ni; Bleszynski Jayich, Ania C.

    2016-08-01

    High-spatial-resolution magnetic imaging has driven important developments in fields ranging from materials science to biology. However, to uncover finer details approaching the nanoscale with greater sensitivity requires the development of a radically new sensor technology. The nitrogen-vacancy (NV) defect in diamond has emerged as a promising candidate for such a sensor on the basis of its atomic size and quantum-limited sensing capabilities. It has remained an outstanding challenge to implement the NV centre as a nanoscale scanning magnetic probe at cryogenic temperatures, however, where many solid-state systems exhibit non-trivial magnetic order. Here, we present NV magnetic imaging down to 6 K with 3 μT Hz-1/2 field sensitivity, and use the technique to image vortices in the iron pnictide superconductor BaFe2(As0.7P0.3)2 with critical temperature Tc = 30 K. The expansion of NV-based magnetic imaging to cryogenic temperatures will enable future studies of previously inaccessible nanoscale magnetism in condensed-matter systems.

  17. Scanned probe imaging of nanoscale magnetism at cryogenic temperatures with a single-spin quantum sensor

    NASA Astrophysics Data System (ADS)

    Pelliccione, Matthew; Jenkins, Alec; Ovartchaiyapong, Preeti; Reetz, Christopher; Emmanouilidou, Eve; Ni, Ni; Bleszynski Jayich, Ania C.

    2016-08-01

    High-spatial-resolution magnetic imaging has driven important developments in fields ranging from materials science to biology. However, to uncover finer details approaching the nanoscale with greater sensitivity requires the development of a radically new sensor technology. The nitrogen–vacancy (NV) defect in diamond has emerged as a promising candidate for such a sensor on the basis of its atomic size and quantum-limited sensing capabilities. It has remained an outstanding challenge to implement the NV centre as a nanoscale scanning magnetic probe at cryogenic temperatures, however, where many solid-state systems exhibit non-trivial magnetic order. Here, we present NV magnetic imaging down to 6 K with 3 μT Hz–1/2 field sensitivity, and use the technique to image vortices in the iron pnictide superconductor BaFe2(As0.7P0.3)2 with critical temperature Tc = 30 K. The expansion of NV-based magnetic imaging to cryogenic temperatures will enable future studies of previously inaccessible nanoscale magnetism in condensed-matter systems.

  18. Scanned probe imaging of nanoscale magnetism at cryogenic temperatures with a single-spin quantum sensor.

    PubMed

    Pelliccione, Matthew; Jenkins, Alec; Ovartchaiyapong, Preeti; Reetz, Christopher; Emmanouilidou, Eve; Ni, Ni; Bleszynski Jayich, Ania C

    2016-08-01

    High-spatial-resolution magnetic imaging has driven important developments in fields ranging from materials science to biology. However, to uncover finer details approaching the nanoscale with greater sensitivity requires the development of a radically new sensor technology. The nitrogen-vacancy (NV) defect in diamond has emerged as a promising candidate for such a sensor on the basis of its atomic size and quantum-limited sensing capabilities. It has remained an outstanding challenge to implement the NV centre as a nanoscale scanning magnetic probe at cryogenic temperatures, however, where many solid-state systems exhibit non-trivial magnetic order. Here, we present NV magnetic imaging down to 6 K with 3 μT Hz(-1/2) field sensitivity, and use the technique to image vortices in the iron pnictide superconductor BaFe2(As0.7P0.3)2 with critical temperature Tc = 30 K. The expansion of NV-based magnetic imaging to cryogenic temperatures will enable future studies of previously inaccessible nanoscale magnetism in condensed-matter systems.

  19. A Small-Molecule Probe for Selective Profiling and Imaging of Monoamine Oxidase B Activities in Models of Parkinson's Disease.

    PubMed

    Li, Lin; Zhang, Cheng-Wu; Ge, Jingyan; Qian, Linghui; Chai, Bing-Han; Zhu, Qing; Lee, Jun-Seok; Lim, Kah-Leong; Yao, Shao Q

    2015-09-01

    The design of the first dual-purpose activity-based probe of monoamine oxidase B (MAO-B) is reported. This probe is highly selective towards MAO-B, even at high MAO-A expression levels, and could sensitively report endogenous MAO-B activities by both in situ proteome profiling and live-cell bioimaging. With a built-in imaging module as part of the probe design, the probe was able to accomplish what all previously reported MAO-B imaging probes failed to do thus far: the live-cell imaging of MAO-B activities without encountering diffusion problems.

  20. Partition-based acquisition model for speed up navigated beta-probe surface imaging

    NASA Astrophysics Data System (ADS)

    Monge, Frédéric; Shakir, Dzhoshkun I.; Navab, Nassir; Jannin, Pierre

    2016-03-01

    Although gross total resection in low-grade glioma surgery leads to a better patient outcome, the in-vivo control of resection borders remains challenging. For this purpose, navigated beta-probe systems combined with 18F-based radiotracer, relying on activity distribution surface estimation, have been proposed to generate reconstructed images. The clinical relevancy has been outlined by early studies where intraoperative functional information is leveraged although inducing low spatial resolution in reconstruction. To improve reconstruction quality, multiple acquisition models have been proposed. They involve the definition of attenuation matrix for designing radiation detection physics. Yet, they require high computational power for efficient intraoperative use. To address the problem, we propose a new acquisition model called Partition Model (PM) considering an existing model where coefficients of the matrix are taken from a look-up table (LUT). Our model is based upon the division of the LUT into averaged homogeneous values for assigning attenuation coefficients. We validated our model using in vitro datasets, where tumors and peri-tumoral tissues have been simulated. We compared our acquisition model with the o_-the-shelf LUT and the raw method. Acquisition models outperformed the raw method in term of tumor contrast (7.97:1 mean T:B) but with a difficulty of real-time use. Both acquisition models reached the same detection performance with references (0.8 mean AUC and 0.77 mean NCC), where PM slightly improves the mean tumor contrast up to 10.1:1 vs 9.9:1 with the LUT model and more importantly, it reduces the mean computation time by 7.5%. Our model gives a faster solution for an intraoperative use of navigated beta-probe surface imaging system, with improved image quality.

  1. Three dimensional imaging of helicon wave fields via magnetic induction probes

    NASA Astrophysics Data System (ADS)

    Reilly, Michael P.

    The majority of data presented in this work is for a helicon plasma discharge driven at 13.56 MHz, 500 Watts input power, 900 Gauss applied magnetic field, 10 mTorr neutral Argon gas, and cylindrical plasma of 5 cm diameter approximately 50 cm long. High frequency magnetic induction probes were developed to measure helicon wave propagation using a new technique for frequency calibration through an impedance analyzer; up to 100 MHz. This work demonstrates magnetic field measurements in high frequency plasma are greatly simplified through this new frequency characterization method. Line-lengths and transmission-cable-types are readily identified as diagnostic limiting factors. The magnetic probe design enables the first 3-dimensional imaging of plasma waves through detailed radial and axial measurements. Strong agreement is obtained between the measured br, btheta, and bz radial profiles with the numerical solutions of helicon waves when a non-uniform radial density profile is considered. The axial helicon wavelength predicted by the non-uniform radial density theory also agrees with the measured wavelength when the full three dimensional wave is accurately analyzed. In some cases, the differences between the three dimensional wavelength and the numerically solved values are less than 35%. This is in contrast to the two dimensional wavelengths which can differ from the numerical values by greater than 100%. We show a complete visual representation of helicon waves through 3-d imaging which provides significantly more accurate analysis of the helicon wavelength. This work also observed a density peak downstream from the antenna/source through axial density measurements with a RF compensated Langmuir probe (calibrated against a 90 GHz microwave interferometer). Here, the downstream density peak is explained in terms of a global energy balance modeled by an axially decaying electron temperature peaked at the source; Te → 3 - 7 eV. This model does not require an

  2. An optical biopsy system with miniaturized Raman and spectral imaging probes; in vivo animal and ex vivo clinical application studies

    NASA Astrophysics Data System (ADS)

    Sato, Hidetoshi; Suzuki, Toshiaki; Andriana, Bibin B.; Morita, Shin'ichi; Maruyama, Atsushi; Shinzawa, Hideyuki; Komachi, Yuichi; Kanai, Gen'ichi; Ura, Nobuo; Masutani, Koji; Matsuura, Yuji; Toi, Masakazu; Shimosegawa, Toru; Ozaki, Yukihiro

    2009-02-01

    An optical biopsy system which equips miniaturized Raman probes, a miniaturized endoscope and a fluorescent image probe has been developed for in vivo studies of live experimental animals. The present report describes basic optical properties of the system and its application studies for in vivo cancer model animals and ex vivo human cancer tissues. It was developed two types of miniaturized Raman probes, micro Raman probe (MRP) made of optical fibers and ball lens hollow optical fiber Raman probe (BHRP) made of single hollow optical fiber (HOF) with a ball lens. The former has rather large working distance (WD), up to one millimeter. The latter has small WD (~300μm) which depends on the focal length of the ball lens. Use of multiple probes with different WD allows one to obtain detailed information of subsurface tissues in the totally noninvasive manner. The probe is enough narrow to be inserted into a biopsy needle (~19G), for observations of the lesion at deeper inside bodies. The miniaturized endoscope has been applied to observe progression of a stomach cancer in the same rat lesion. It was succeeded to visualize structure of non-stained cancer tissue in live model animals by the fluorescent image technique. The system was also applied to ex vivo studies of human breast and stomach cancers.

  3. Transvaginal photoacoustic imaging probe and system based on a multiport fiber-optic beamsplitter and a real time imager for ovarian cancer detection

    NASA Astrophysics Data System (ADS)

    Kumavor, Patrick D.; Alqasemi, Umar; Tavakoli, Behnoosh; Li, Hai; Yang, Yi; Zhu, Quing

    2013-03-01

    This paper presents a real-time transvaginal photoacoustic imaging probe for imaging human ovaries in vivo. The probe consists of a high-throughput (up to 80%) fiber-optic 1 x 19 beamsplitters, a commercial array ultrasound transducer, and a fiber protective sheath. The beamsplitter has a 940-micron core diameter input fiber and 240-micron core diameter output fibers numbering 36. The 36 small-core output fibers surround the ultrasound transducer and delivers light to the tissue during imaging. A protective sheath, modeled in the form of the transducer using a 3-D printer, encloses the transducer with array of fibers. A real-time image acquisition system collects and processes the photoacoustic RF signals from the transducer, and displays the images formed on a monitor in real time. Additionally, the system is capable of coregistered pulse-echo ultrasound imaging. In this way, we obtain both morphological and functional information from the ovarian tissue. Photoacousitc images of malignant human ovaries taken ex vivo with the probe revealed blood vascular and networks that was distinguishable from normal ovaries, making the probe potential useful for characterizing ovarian tissue.

  4. Fabrication and operation of GRIN probes for in vivo fluorescence cellular imaging of internal organs in small animals

    PubMed Central

    Kim, Jun Ki; Lee, Woei Ming; Kim, Pilhan; Choi, Myunghwan; Jung, Keehoon; Kim, Seonghoon; Yun, Seok Hyun

    2013-01-01

    Intravital fluorescence microscopy has emerged as a powerful technique to visualize cellular processes in vivo. However, the size of the objective lenses has limited physical accessibility to various tissue sites in the internal organs of small animals. The use of small-diameter probes using graded-index (GRIN) lenses expands the capabilities of conventional intravital microscopes into minimally invasive internal organs imaging. In this protocol, we describe the detailed steps for the fabrication of front- and side-view GRIN probes and the integration and operation of the probes in a confocal microscope for visualizing fluorescent cells and microvasculature in various murine organs. We further present longitudinal imaging of immune cells in renal allografts and the tumor development in the colon. The fabrication and integration can be completed in 5–7 hours, and a typical in vivo imaging session takes 1–2 hours. PMID:22767088

  5. High Precision Imaging of Microscopic Spread of Glioblastoma with a Targeted Ultrasensitive SERRS Molecular Imaging Probe

    PubMed Central

    Huang, Ruimin; Harmsen, Stefan; Samii, Jason M.; Karabeber, Hazem; Pitter, Kenneth L.; Holland, Eric C.; Kircher, Moritz F.

    2016-01-01

    The dismal prognosis of patients with malignant brain tumors such as glioblastoma multiforme (GBM) is attributed mostly to their diffuse growth pattern and early microscopic tumor spread to distant regions of the brain. Because the microscopic tumor foci cannot be visualized with current imaging modalities, it remains impossible to direct treatments optimally. Here we explored the ability of integrin-targeted surface-enhanced resonance Raman spectroscopy (SERRS) nanoparticles to depict the true tumor extent in a GBM mouse model that closely mimics the pathology in humans. The recently developed SERRS-nanoparticles have a sensitivity of detection in the femtomolar range. An RGD-peptide-conjugated version for integrin-targeting (RGD-SERRS) was compared directly to its non-targeted RAD-SERRS control in the same mice via Raman multiplexing. Pre-blocking with RGD peptide before injection of RGD-SERRS nanoparticles was used to verify the specificity of integrin-targeting. In contrast to the current belief that the enhanced permeability and retention (EPR) effect results in a baseline uptake of nanoparticles regardless of their surface chemistry, integrin-targeting was shown to be highly specific, with markedly lower accumulation after pre-blocking. While the non-targeted SERRS particles enabled delineation of the main tumor, the RGD-SERRS nanoparticles afforded a major improvement in visualization of the true extent and the diffuse margins of the main tumor. This included the detection of unexpected tumor areas distant to the main tumor, tracks of migrating cells of 2-3 cells in diameter, and even isolated distant tumor cell clusters of less than 5 cells. This Raman spectroscopy-based nanoparticle-imaging technology holds promise to allow high precision visualization of the true extent of malignant brain tumors. PMID:27279902

  6. Advanced Magnetic Resonance Imaging techniques to probe muscle structure and function

    NASA Astrophysics Data System (ADS)

    Malis, Vadim

    aging, strain rate during isometric contraction was significantly reduced in the seniors; presumably from decrease in muscle slack and increase in stiffness with age. Other parameters of interest from this study that allow inferences on the ECM and lateral transmission are the asymmetry of deformation in the fiber cross section as well as the angle between the SR and muscle fiber. The last part of thesis, which is a 'work-in-progress', is the extension to 3D SR tensor mapping using a 3D spatial, 3D velocity encoded imaging sequence. This is combined with Diffusion Tensor Imaging to obtain the lead eigenvector (muscle fiber direction) at each voxel. The 3D SR is then rotated to the basis of the DTI to obtain a 'Fiber Aligned Strain rate: FASR'. The off diagonal elements of FASR are shear strain terms. Detailed analysis of the shear strain will provide a unique non-invasive method to probe lateral transmission.

  7. A rapid and automated relocation method of an AFM probe for high-resolution imaging

    NASA Astrophysics Data System (ADS)

    Zhou, Peilin; Yu, Haibo; Shi, Jialin; Jiao, Niandong; Wang, Zhidong; Wang, Yuechao; Liu, Lianqing

    2016-09-01

    The atomic force microscope (AFM) is one of the most powerful tools for high-resolution imaging and high-precision positioning for nanomanipulation. The selection of the scanning area of the AFM depends on the use of the optical microscope. However, the resolution of an optical microscope is generally no larger than 200 nm owing to wavelength limitations of visible light. Taking into consideration the two determinants of relocation—relative angular rotation and positional offset between the AFM probe and nano target—it is therefore extremely challenging to precisely relocate the AFM probe to the initial scan/manipulation area for the same nano target after the AFM probe has been replaced, or after the sample has been moved. In this paper, we investigate a rapid automated relocation method for the nano target of an AFM using a coordinate transformation. The relocation process is both simple and rapid; moreover, multiple nano targets can be relocated by only identifying a pair of reference points. It possesses a centimeter-scale location range and nano-scale precision. The main advantages of this method are that it overcomes the limitations associated with the resolution of optical microscopes, and that it is label-free on the target areas, which means that it does not require the use of special artificial markers on the target sample areas. Relocation experiments using nanospheres, DNA, SWCNTs, and nano patterns amply demonstrate the practicality and efficiency of the proposed method, which provides technical support for mass nanomanipulation and detection based on AFM for multiple nano targets that are widely distributed in a large area.

  8. A rapid and automated relocation method of an AFM probe for high-resolution imaging.

    PubMed

    Zhou, Peilin; Yu, Haibo; Shi, Jialin; Jiao, Niandong; Wang, Zhidong; Wang, Yuechao; Liu, Lianqing

    2016-09-30

    The atomic force microscope (AFM) is one of the most powerful tools for high-resolution imaging and high-precision positioning for nanomanipulation. The selection of the scanning area of the AFM depends on the use of the optical microscope. However, the resolution of an optical microscope is generally no larger than 200 nm owing to wavelength limitations of visible light. Taking into consideration the two determinants of relocation-relative angular rotation and positional offset between the AFM probe and nano target-it is therefore extremely challenging to precisely relocate the AFM probe to the initial scan/manipulation area for the same nano target after the AFM probe has been replaced, or after the sample has been moved. In this paper, we investigate a rapid automated relocation method for the nano target of an AFM using a coordinate transformation. The relocation process is both simple and rapid; moreover, multiple nano targets can be relocated by only identifying a pair of reference points. It possesses a centimeter-scale location range and nano-scale precision. The main advantages of this method are that it overcomes the limitations associated with the resolution of optical microscopes, and that it is label-free on the target areas, which means that it does not require the use of special artificial markers on the target sample areas. Relocation experiments using nanospheres, DNA, SWCNTs, and nano patterns amply demonstrate the practicality and efficiency of the proposed method, which provides technical support for mass nanomanipulation and detection based on AFM for multiple nano targets that are widely distributed in a large area. PMID:27559679

  9. Scanning Probe Microscope Imaging with Principal Component Analysis of Cell Types

    NASA Astrophysics Data System (ADS)

    Ayres, V. M.; Goolsby, B.; Salam, F.; Yu, M.-M.; Xi, Ning; Wang, D.

    2002-03-01

    Scanning Probe Microscopy provides high resolution imaging of specimens, including biological specimens. Scanning Probe Microscope-based nanomanipulation is a newly emerging area that offers an orders-of-magnitude improvement over current manipulation capabilities. Together, the two offer the possibility of site-specific direct investigations of biological events. We present our research toward the development of a landmark recognition scheme for use within an adaptive nonlinear neural network controller, for high end control of the X-Y motion of an SPM tip. Our goal is sensing/landmark recognition within an overall feedback control formulation that will ultimately be used to accurately steer the probes tip along a prescribed trajectory to a designated biological site. In a different approach than haptic feedback-based nanomanipulation, the human operator is eliminated except for high end control and a training algorithm is substituted instead. Principal Component Analysis is used for landmark recognition of specific biological features. Principal Component Analysis is a pattern recognition technique that selects/extracts key features from a data set. The feature selection process transforms the data space into the feature space by reducing the dimensionality of the data set. The reduced data set is comprised of the most effective features that contain the intrinsic information of the data. In this work, Principal Component Analysis is applied to recognition of leukocytes (white blood cells) and erythrocytes (red blood cells), and further distinguishing between neutrophilic and lymphocytic leukocyte varieties. We find that that information from an initial 512x512 (xyz) SPM data set can be effectively represented by eight eigenvectors.

  10. Imaging trans-cellular neurexin-neuroligin interactions by enzymatic probe ligation.

    PubMed

    Liu, Daniel S; Loh, Ken H; Lam, Stephanie S; White, Katharine A; Ting, Alice Y

    2013-01-01

    Neurexin and neuroligin are transmembrane adhesion proteins that play an important role in organizing the neuronal synaptic cleft. Our lab previously reported a method for imaging the trans-synaptic binding of neurexin and neuroligin called BLINC (Biotin Labeling of INtercellular Contacts). In BLINC, biotin ligase (BirA) is fused to one protein while its 15-amino acid acceptor peptide substrate (AP) is fused to the binding partner. When the two fusion proteins interact across cellular junctions, BirA catalyzes the site-specific biotinylation of AP, which can be read out by staining with streptavidin-fluorophore conjugates. Here, we report that BLINC in neurons cannot be reproduced using the reporter constructs and labeling protocol previously described. We uncover the technical reasons for the lack of reproducibilty and then re-design the BLINC reporters and labeling protocol to achieve neurexin-neuroligin BLINC imaging in neuron cultures. In addition, we introduce a new method, based on lipoic acid ligase instead of biotin ligase, to image trans-cellular neurexin-neuroligin interactions in human embryonic kidney cells and in neuron cultures. This method, called ID-PRIME for Interaction-Dependent PRobe Incorporation Mediated by Enzymes, is more robust than BLINC due to higher surface expression of lipoic acid ligase fusion constructs, gives stronger and more localized labeling, and is more versatile than BLINC in terms of signal readout. ID-PRIME expands the toolkit of methods available to study trans-cellular protein-protein interactions in living systems.

  11. Maltodextrin-based imaging probes detect bacteria in vivo with high sensitivity and specificity

    NASA Astrophysics Data System (ADS)

    Ning, Xinghai; Lee, Seungjun; Wang, Zhirui; Kim, Dongin; Stubblefield, Bryan; Gilbert, Eric; Murthy, Niren

    2011-08-01

    The diagnosis of bacterial infections remains a major challenge in medicine. Although numerous contrast agents have been developed to image bacteria, their clinical impact has been minimal because they are unable to detect small numbers of bacteria in vivo, and cannot distinguish infections from other pathologies such as cancer and inflammation. Here, we present a family of contrast agents, termed maltodextrin-based imaging probes (MDPs), which can detect bacteria in vivo with a sensitivity two orders of magnitude higher than previously reported, and can detect bacteria using a bacteria-specific mechanism that is independent of host response and secondary pathologies. MDPs are composed of a fluorescent dye conjugated to maltohexaose, and are rapidly internalized through the bacteria-specific maltodextrin transport pathway, endowing the MDPs with a unique combination of high sensitivity and specificity for bacteria. Here, we show that MDPs selectively accumulate within bacteria at millimolar concentrations, and are a thousand-fold more specific for bacteria than mammalian cells. Furthermore, we demonstrate that MDPs can image as few as 105 colony-forming units in vivo and can discriminate between active bacteria and inflammation induced by either lipopolysaccharides or metabolically inactive bacteria.

  12. Cathepsin Activity-Based Probes and Inhibitor for Preclinical Atherosclerosis Imaging and Macrophage Depletion

    PubMed Central

    Abd-Elrahman, Ihab; Kosuge, Hisanori; Wises Sadan, Tommy; Ben-Nun, Yael; Meir, Karen; Rubinstein, Chen; Bogyo, Matthew; McConnell, Michael V.

    2016-01-01

    Background and Purpose Cardiovascular disease is the leading cause of death worldwide, mainly due to an increasing prevalence of atherosclerosis characterized by inflammatory plaques. Plaques with high levels of macrophage infiltration are considered “vulnerable” while those that do not have significant inflammation are considered stable; cathepsin protease activity is highly elevated in macrophages of vulnerable plaques and contributes to plaque instability. Establishing novel tools for non-invasive molecular imaging of macrophages in plaques could aid in preclinical studies and evaluation of therapeutics. Furthermore, compounds that reduce the macrophage content within plaques should ultimately impact care for this disease. Methods We have applied quenched fluorescent cathepsin activity-based probes (ABPs) to a murine atherosclerosis model and evaluated their use for in vivo imaging using fluorescent molecular tomography (FMT), as well as ex vivo fluorescence imaging and fluorescent microscopy. Additionally, freshly dissected human carotid plaques were treated with our potent cathepsin inhibitor and macrophage apoptosis was evaluated by fluorescent microscopy. Results We demonstrate that our ABPs accurately detect murine atherosclerotic plaques non-invasively, identifying cathepsin activity within plaque macrophages. In addition, our cathepsin inhibitor selectively induced cell apoptosis of 55%±10% of the macrophage within excised human atherosclerotic plaques. Conclusions Cathepsin ABPs present a rapid diagnostic tool for macrophage detection in atherosclerotic plaque. Our inhibitor confirms cathepsin-targeting as a promising approach to treat atherosclerotic plaque inflammation. PMID:27532109

  13. Biomarkers and Molecular Probes for Cell Death Imaging and Targeted Therapeutics

    PubMed Central

    Smith, Bryan A.; Smith, Bradley D.

    2012-01-01

    Cell death is a critically important biological process. Disruption of homeostasis, either by excessive or deficient cell death, is a hallmark of many pathological conditions. Recent research advances have greatly increased our molecular understanding of cell death and its role in a range of diseases and therapeutic treatments. Central to these ongoing research and clinical efforts is the need for imaging technologies that can locate and identify cell death in a wide array of in vitro and in vivo biomedical samples with varied spatiotemporal requirements. This review article summarizes community efforts over the past five years to identify useful biomarkers for dead and dying cells, and to develop molecular probes that target these biomarkers for optical, radionuclear, or magnetic resonance imaging. Apoptosis biomarkers are classified as either intracellular (caspase enzymes, mitochondrial membrane potential, cytosolic proteins) or extracellular (plasma membrane phospholipids, membrane potential, surface exposed histones). Necrosis, autophagy, and senescence biomarkers are described, as well as unexplored cell death biomarkers. The article discusses possible chemotherapeutic and theranostic strategies, and concludes with a summary of current challenges and expected eventual rewards of clinical cell death imaging. PMID:22989049

  14. Probing the resonant states of Cl2 using velocity slice imaging

    NASA Astrophysics Data System (ADS)

    Gope, Krishnendu; Prabhudesai, Vaibhav S.; Mason, Nigel J.; Krishnakumar, E.

    2016-01-01

    The negative ion resonances in molecular chlorine are probed using velocity slice imaging of the Cl- fragment produced in dissociative electron attachment (DEA). The capability of the velocity slice imaging to cover the entire 360° allows us to obtain clear evidence for the presence of the {}{{2}}{{Σ }}{{u}}+ resonance in the 2.5 eV DEA peak along with the presence of {}{{2}}{{\\Pi }}{{g}}. The {}{{2}}{{Σ }}{{u}}+ resonance is expected to be the contributor only to the 0 eV DEA peak. Its presence in the 2.5 eV DEA peak calls for a relook at the theoretical calculations which have not identified any {} {} {{Σ }} resonance in the 2.5 eV peak. We also identify the presence of the {}{{2}}{{\\Pi }}{{g}} and {}{{2}}{{Σ }}{{g}}+ resonances in the 5.6 eV peak. The momentum images indicate no signature of a resonant contribution in the dipolar dissociation region up to 80 eV.

  15. SU-E-I-81: Targeting of HER2-Expressing Tumors with Dual PET-MR Imaging Probes

    SciTech Connect

    Xu, P; Peng, Y; Sun, M; Yang, X

    2015-06-15

    Purpose: The detection of human epidermal growth factor receptor type 2 (HER2) expression in malignant tumors provides important information influencing patient management. Radionuclide in vivo imaging of HER2 may permit the detection of HER2 in both primary tumors and metastases by a single noninvasive procedure. Trastuzumab, effective in about 15 % of women with breast cancer, downregulates signalling through the Akt/PI3K and MAPK pathways.These pathways modulate metabolism which can be monitored by positron emission tomography (PET) and magnetic resonance imaging (MRI). Methods: The relationship between response of HER2 overexpressing tumours and changes in imaging PET or SPECT and MRI will be examined by a integrated bimodal imaging probe.Small (7 kDa) high-affinity anti-HER2 Affibody molecules and KCCYSL targeting peptide may be suitable tracers for visualization of HER2-expressing tumors. Peptide-conjugated iron oxide nanoparticles (Fe3O4 NPs) as MRI imaging and CB-TE2A as PET imaging are integrated into a single synthetic molecule in the HER2 positive cancer. Results: One of targeted contrast bimodal imaging probe agents was synthesized and evaluated to target HER2-expressing tumors in a HER2 positive rat model. We will report the newest results regarding the development of bimodal imaging probes. Conclusion: The preliminary results of the bimodal imaging probe presents high correlation of MRI signal and PET imaging intensity in vivo. This unique feature can hardly be obtained by single model contrast agents. It is envisioned that this bimodal agents can hold great potential for accurate detection of HER2-expressing tumors which are critical for clinical management of the disease.

  16. Advanced slow-magic angle spinning probe for magnetic resonance imaging and spectroscopy

    DOEpatents

    Wind, Robert A.; Hu, Jian Zhi; Minard, Kevin R.; Rommereim, Donald N.

    2006-01-24

    The present invention relates to a probe and processes useful for magnetic resonance imaging and spectroscopy instruments. More particularly, the invention relates to a MR probe and processes for obtaining resolution enhancements of fluid objects, including live specimens, using an ultra-slow (magic angle) spinning (MAS) of the specimen combined with a modified phase-corrected magic angle turning (PHORMAT) pulse sequence. Proton NMR spectra were measured of the torso and the top part of the belly of a female BALBc mouse in a 2T field, while spinning the animal at a speed of 1.5 Hz. Results show that even in this relatively low field with PHORMAT, an isotropic spectrum is obtained with line widths that are a factor 4.6 smaller than those obtained in a stationary mouse. Resolution of 1H NMR metabolite spectra are thus significantly enhanced. Results indicate that PHORMAT has the potential to significantly increase the utility of 1H NMR spectroscopy for in vivo biochemical, biomedical and/or medical applications involving large-sized biological objects such as mice, rats and even humans within a hospital setting. For small-sized objects, including biological objects, such as excised tissues, organs, live bacterial cells, and biofilms, use of PASS at a spinning rate of 30 Hz and above is preferred.

  17. Nanomechanical and topographical imaging of living cells by atomic force microscopy with colloidal probes

    SciTech Connect

    Puricelli, Luca; Galluzzi, Massimiliano; Schulte, Carsten; Podestà, Alessandro Milani, Paolo

    2015-03-15

    Atomic Force Microscopy (AFM) has a great potential as a tool to characterize mechanical and morphological properties of living cells; these properties have been shown to correlate with cells’ fate and patho-physiological state in view of the development of novel early-diagnostic strategies. Although several reports have described experimental and technical approaches for the characterization of cellular elasticity by means of AFM, a robust and commonly accepted methodology is still lacking. Here, we show that micrometric spherical probes (also known as colloidal probes) are well suited for performing a combined topographic and mechanical analysis of living cells, with spatial resolution suitable for a complete and accurate mapping of cell morphological and elastic properties, and superior reliability and accuracy in the mechanical measurements with respect to conventional and widely used sharp AFM tips. We address a number of issues concerning the nanomechanical analysis, including the applicability of contact mechanical models and the impact of a constrained contact geometry on the measured Young’s modulus (the finite-thickness effect). We have tested our protocol by imaging living PC12 and MDA-MB-231 cells, in order to demonstrate the importance of the correction of the finite-thickness effect and the change in Young’s modulus induced by the action of a cytoskeleton-targeting drug.

  18. HER2- and EGFR-specific affiprobes: novel recombinant optical probes for cell imaging.

    PubMed

    Lyakhov, Ilya; Zielinski, Rafal; Kuban, Monika; Kramer-Marek, Gabriela; Fisher, Robert; Chertov, Oleg; Bindu, Lakshman; Capala, Jacek

    2010-02-15

    The human epidermal growth factor receptors, EGFR and HER2, are members of the EGFR family of cell-surface receptors/tyrosine kinases. EGFR- and HER2-positive cancers represent a more aggressive disease with greater likelihood of recurrence, poorer prognosis, and decreased survival rate, compared to EGFR- or HER2-negative cancers. The details of HER2 proto-oncogenic functions are not deeply understood, partially because of a restricted availability of tools for EGFR and HER2 detection (A. Sorkin and L. K. Goh, Exp. Cell Res. 2009, 315, 683-696). We have created photostable and relatively simple-to-produce imaging probes for in vitro staining of EGFR and HER2. These new reagents, called affiprobes, consist of a targeting moiety, a HER2- or EGFR-specific Affibody molecule, and a fluorescent moiety, mCherry (red) or EGFP (green). Our flow cytometry and confocal microscopy experiments demonstrated high specificity and signal/background ratio of affiprobes. Affiprobes are able to stain both live cells and frozen tumor xenograph sections. This type of optical probe can easily be extended for targeting other cell-surface antigens/ receptors. PMID:20052708

  19. Dual-Color Fluorescence Imaging of Magnetic Nanoparticles in Live Cancer Cells Using Conjugated Polymer Probes

    PubMed Central

    Sun, Minjie; Sun, Bin; Liu, Yun; Shen, Qun-Dong; Jiang, Shaojun

    2016-01-01

    Rapid growth in biological applications of nanomaterials brings about pressing needs for exploring nanomaterial-cell interactions. Cationic blue-emissive and anionic green-emissive conjugated polymers are applied as dual-color fluorescence probes to the surface of negatively charged magnetic nanoparticles through sequentially electrostatic adsorption. These conjugated polymers have large extinction coefficients and high fluorescence quantum yield (82% for PFN and 62% for ThPFS). Thereby, one can visualize trace amount (2.7 μg/mL) of fluorescence-labeled nanoparticles within cancer cells by confocal laser scanning microscopy. Fluorescence labeling by the conjugated polymers is also validated for quantitative determination of the internalized nanoparticles in each individual cell by flow cytometry analysis. Extensive overlap of blue and green fluorescence signals in the cytoplasm indicates that both conjugated polymer probes tightly bind to the surface of the nanoparticles during cellular internalization. The highly charged and fluorescence-labeled nanoparticles non-specifically bind to the cell membranes, followed by cellular uptake through endocytosis. The nanoparticles form aggregates inside endosomes, which yields a punctuated staining pattern. Cellular internalization of the nanoparticles is dependent on the dosage and time. Uptake efficiency can be enhanced three-fold by application of an external magnetic field. The nanoparticles are low cytotoxicity and suitable for simultaneously noninvasive fluorescence and magnetic resonance imaging application. PMID:26931282

  20. Dual-Color Fluorescence Imaging of Magnetic Nanoparticles in Live Cancer Cells Using Conjugated Polymer Probes.

    PubMed

    Sun, Minjie; Sun, Bin; Liu, Yun; Shen, Qun-Dong; Jiang, Shaojun

    2016-01-01

    Rapid growth in biological applications of nanomaterials brings about pressing needs for exploring nanomaterial-cell interactions. Cationic blue-emissive and anionic green-emissive conjugated polymers are applied as dual-color fluorescence probes to the surface of negatively charged magnetic nanoparticles through sequentially electrostatic adsorption. These conjugated polymers have large extinction coefficients and high fluorescence quantum yield (82% for PFN and 62% for ThPFS). Thereby, one can visualize trace amount (2.7 μg/mL) of fluorescence-labeled nanoparticles within cancer cells by confocal laser scanning microscopy. Fluorescence labeling by the conjugated polymers is also validated for quantitative determination of the internalized nanoparticles in each individual cell by flow cytometry analysis. Extensive overlap of blue and green fluorescence signals in the cytoplasm indicates that both conjugated polymer probes tightly bind to the surface of the nanoparticles during cellular internalization. The highly charged and fluorescence-labeled nanoparticles non-specifically bind to the cell membranes, followed by cellular uptake through endocytosis. The nanoparticles form aggregates inside endosomes, which yields a punctuated staining pattern. Cellular internalization of the nanoparticles is dependent on the dosage and time. Uptake efficiency can be enhanced three-fold by application of an external magnetic field. The nanoparticles are low cytotoxicity and suitable for simultaneously noninvasive fluorescence and magnetic resonance imaging application. PMID:26931282

  1. Synthesis of [125I]IodoDPA-713, a New Probe for Imaging Inflammation

    PubMed Central

    Wang, Haofan; Pullambhatla, Mrudula; Guilarte, Tomas R.; Mease, Ronnie C.; Pomper, Martin G.

    2009-01-01

    [125I]IodoDPA-713 [125I]1, which targets the translocator protein (TSPO, 18 KDa), was synthesized in seven steps from methyl-4-methoxybenzoate as a tool for quantification of inflammation in preclinical models. Preliminary in vitro autoradiography and in vivo small animal imaging were performed using [125I]1 in a neurotoxicant-treated rat and in a murine model of lung inflammation, respectively. The radiochemical yield of [125I]1 was 44 ± 6% with a specific radioactivity of 51.8 GBq/μmol (1,400 mCi/μmol) and > 99% radiochemical purity. Preliminary studies showed that [125I]1 demonstrated increased specific binding to TSPO in a neurotoxicant-treated rat and increased radiopharmaceutical uptake in the lungs of an experimental inflammation model of lung inflammation. Compound [125I]1 is a new, convenient probe for preclinical studies of TSPO activity. PMID:19703411

  2. Synthesis of [{sup 125}I]iodoDPA-713: A new probe for imaging inflammation

    SciTech Connect

    Wang, Haofan; Pullambhatla, Mrudula; Guilarte, Tomas R.; Mease, Ronnie C.; Pomper, Martin G.

    2009-11-06

    [{sup 125}I]IodoDPA-713 [{sup 125}I]1, which targets the translocator protein (TSPO, 18 kDa), was synthesized in seven steps from methyl-4-methoxybenzoate as a tool for quantification of inflammation in preclinical models. Preliminary in vitro autoradiography and in vivo small animal imaging were performed using [{sup 125}I]1 in a neurotoxicant-treated rat and in a murine model of lung inflammation, respectively. The radiochemical yield of [{sup 125}I]1 was 44 {+-} 6% with a specific radioactivity of 51.8 GBq/{mu}mol (1400 mCi/{mu}mol) and >99% radiochemical purity. Preliminary studies showed that [{sup 125}I]1 demonstrated increased specific binding to TSPO in a neurotoxicant-treated rat and increased radiopharmaceutical uptake in the lungs of an experimental inflammation model of lung inflammation. Compound [{sup 125}I]1 is a new, convenient probe for preclinical studies of TSPO activity.

  3. Low magnification differential phase contrast imaging of electric fields in crystals with fine electron probes.

    PubMed

    Taplin, D J; Shibata, N; Weyland, M; Findlay, S D

    2016-10-01

    To correlate atomistic structure with longer range electric field distribution within materials, it is necessary to use atomically fine electron probes and specimens in on-axis orientation. However, electric field mapping via low magnification differential phase contrast imaging under these conditions raises challenges: electron scattering tends to reduce the beam deflection due to the electric field strength from what simple models predict, and other effects, most notably crystal mistilt, can lead to asymmetric intensity redistribution in the diffraction pattern which is difficult to distinguish from that produced by long range electric fields. Using electron scattering simulations, we explore the effects of such factors on the reliable interpretation and measurement of electric field distributions. In addition to these limitations of principle, some limitations of practice when seeking to perform such measurements using segmented detector systems are also discussed.

  4. Probing Tissue Microstructure with Restriction Spectrum Imaging: Histological and Theoretical Validation

    PubMed Central

    White, Nathan S.; Leergaard, Trygve B.; D’Arceuil, Helen; Bjaalie, Jan G.; Dale, Anders M.

    2012-01-01

    Diffusion magnetic resonance imaging (dMRI) is a powerful tool for studying biological tissue microarchitectures in vivo. Recently, there has been increased effort to develop quantitative dMRI methods to probe both length scale and orientation information in diffusion media. Diffusion spectrum imaging (DSI) is one such approach that aims to resolve such information on the basis of the three-dimensional diffusion propagator at each voxel. However, in practice only the orientation component of the propagator function is preserved when deriving the orientation distribution function. Here, we demonstrate how a straightforward extension of the linear spherical deconvolution (SD) model can be used to probe tissue orientation structures over a range (or “spectrum”) of length scales with minimal assumptions on the underlying microarchitecture. Using high b-value Cartesian q-space data on a fixed rat brain sample, we demonstrate how this “restriction spectrum imaging” (RSI) model allows for separating the volume fraction and orientation distribution of hindered and restricted diffusion, which we argue stems primarily from diffusion in the extra- and intra-neurite water compartment, respectively. Moreover, we demonstrate how empirical RSI estimates of the neurite orientation distribution and volume fraction capture important additional structure not afforded by traditional DSI or fixed-scale SD-like reconstructions, particularly in grey matter. We conclude that incorporating length scale information in geometric models of diffusion offers promise for advancing state-of-the-art dMRI methods beyond white matter into grey matter structures while allowing more detailed quantitative characterization of water compartmentalization and histoarchitecture of healthy and diseased tissue. PMID:23169482

  5. Fourier transform infrared imaging and infrared fiber optic probe spectroscopy identify collagen type in connective tissues.

    PubMed

    Hanifi, Arash; McCarthy, Helen; Roberts, Sally; Pleshko, Nancy

    2013-01-01

    Hyaline cartilage and mechanically inferior fibrocartilage consisting of mixed collagen types are frequently found together in repairing articular cartilage. The present study seeks to develop methodology to identify collagen type and other tissue components using Fourier transform infrared (FTIR) spectral evaluation of matrix composition in combination with multivariate analyses. FTIR spectra of the primary molecular components of repair cartilage, types I and II collagen, and aggrecan, were used to develop multivariate spectral models for discrimination of the matrix components of the tissues of interest. Infrared imaging data were collected from bovine bone, tendon, normal cartilage, meniscus and human repair cartilage tissues, and composition predicted using partial least squares analyses. Histology and immunohistochemistry results were used as standards for validation. Infrared fiber optic probe spectral data were also obtained from meniscus (a tissue with mixed collagen types) to evaluate the potential of this method for identification of collagen type in a minimally-invasive clinical application. Concentration profiles of the tissue components obtained from multivariate analysis were in excellent agreement with histology and immunohistochemistry results. Bone and tendon showed a uniform distribution of predominantly type I collagen through the tissue. Normal cartilage showed a distribution of type II collagen and proteoglycan similar to the known composition, while in repair cartilage, the spectral distribution of both types I and II collagen were similar to that observed via immunohistochemistry. Using the probe, the outer and inner regions of the meniscus were shown to be primarily composed of type I and II collagen, respectively, in accordance with immunohistochemistry data. In summary, multivariate analysis of infrared spectra can indeed be used to differentiate collagen type I and type II, even in the presence of proteoglycan, in connective tissues

  6. Noninvasive fluorescence imaging in animal models of stroke.

    PubMed

    Stemmer, N; Mehnert, J; Steinbrink, J; Wunder, A

    2012-01-01

    Noninvasive fluorescence imaging (NFI) is a powerful tool to study physiology and pathophysiology in animal disease models. NFI has been successfully applied in a number of animal disease models including cancer, arthritis, and stroke. Furthermore, several applications in humans have been described. NFI is widely available in research laboratories because it has a number of advantages: It uses non-ionizing radiation and requires comparably simple, inexpensive instrumentation, and easy to handle. Fluorochromes can be detected with high sensitivity, and image acquisition time is relatively short. Furthermore, a plethora of fluorescent imaging agents is available including unspecific, target-specific, and activatable imaging probes. With these probes, biological processes such as inflammation, cell death or enzyme activity, and many others can be visualized in living animals. This review offers an overview of current approaches in NFI of stroke pathophysiology in animal models of cerebral ischemia. First, the instrumentation and the different types of imaging agents for NFI are described. Second, a short introduction to animal models of stroke is provided. Third, examples for NFI in animal models of stroke are given. Finally, the use of NFI in human stroke is critically discussed.

  7. Sapphire ball lensed fiber probe for common-path optical coherence tomography in ocular imaging and sensing

    NASA Astrophysics Data System (ADS)

    Zhao, Mingtao; Huang, Yong; Kang, Jin U.

    2013-03-01

    We describe a novel common-path optical coherence tomography (CP-OCT) fiber probe design using a sapphire ball lens for cross-sectional imaging and sensing in retina vitrectomy surgery. Single mode Gaussian beam (TEM00) simulation was used to optimize lateral resolution and working distance (WD) of the common-path probe. A theoretical sensitivity model for CP-OCT was prosed to assess its optimal performance based an unbalanced photodetector configuration. Two probe designs with working distances (WD) 415μm and 1221μm and lateral resolution 11μm and 18μm, respectively were implemented with sensitivity up to 88dB. The designs are also fully compatible with conventional Michelson interferometer based OCT configurations. The reference plane of the probe, located at the distal beam exit interface of the single mode fiber (SMF), was encased within a 25-gauge hypodermic needle by the sapphire ball lens facilitates its applications in bloody and harsh environments. The performances of the fiber probe with 11μm of lateral resolution and 19μm of axial resolution were demonstrated by cross-sectional imaging of a cow cornea and retina in vitro with a 1310nm swept source OCT system. This probe was also attached to a piezoelectric motor for active compensation of physiological tremor for handheld retinal surgical tools.

  8. Efficient Two-Photon Fluorescent Probe for Nitroreductase Detection and Hypoxia Imaging in Tumor Cells and Tissues.

    PubMed

    Zhang, Jing; Liu, Hong-Wen; Hu, Xiao-Xiao; Li, Jin; Liang, Li-Hui; Zhang, Xiao-Bing; Tan, Weihong

    2015-12-01

    Hypoxia plays an important role in tumor progression, and the development of efficient methods for monitoring hypoxic degree in living systems is of great biomedical importance. In the solid tumors, the nitroreductase level is directly corresponded with the hypoxic status. Many one-photon excited fluorescent probes have been developed for hypoxia imaging in tumor cells via the detection of nitroreductase level. However, two-photon excited probes are more suitable for bioimaging. In this work, a two-photon probe 1 for nitroreductase detection and hypoxic status monitoring in living tumor cells and tissues was reported for the first time. The detection is based on the fact that the nitro-group of probe 1 could be selectively reduced to an amino-group by nitroreductase in the presence of reduced NADH, following by a 1,6-rearrangement-elimination to release the fluorophore, resulting in the enhancement of fluorescence. The probe exhibited both one-photon and two-photon excited remarkable fluorescence enhancement (∼70-fold) for nitroreductase, which afforded a high sensitivity for nitroreductase, with a detection limit of 20 ng/mL observed. Moreover, the applications of the probe for fluorescent bioimaging of hypoxia in living cells and two-photon bioimaging in tissues were carried out, with tissue-imaging depths of 70-160 μm observed, which demonstrates its practical application in complex biosystems.

  9. In vivo intra-operative breast tumor margin detection using a portable OCT system with a handheld surgical imaging probe

    NASA Astrophysics Data System (ADS)

    Erickson-Bhatt, Sarah J.; Nolan, Ryan; Shemonski, Nathan D.; Adie, Steven G.; Putney, Jeffrey; Darga, Donald; McCormick, Daniel T.; Cittadine, Andrew; Marjanovic, Marina; Chaney, Eric J.; Monroy, Guillermo L.; South, Fredrick; Carney, P. Scott; Cradock, Kimberly A.; Liu, Z. George; Ray, Partha S.; Boppart, Stephen A.

    2014-02-01

    Breast-conserving surgery is a frequent option for women with stage I and II breast cancer, and with radiation treatment, can be as effective as a mastectomy. However, adequate margin detection remains a challenge, and too often additional surgeries are required. Optical coherence tomography (OCT) provides a potential method for real-time, high-resolution imaging of breast tissue during surgery. Intra-operative OCT imaging of excised breast tissues has been previously demonstrated by several groups. In this study, a novel handheld surgical probe-based OCT system is introduced, which was used by the surgeon to image in vivo, within the tumor cavity, and immediately following tumor removal in order to detect the presence of any remaining cancer. Following resection, study investigators imaged the excised tissue with the same probe for comparison. We present OCT images obtained from over 15 patients during lumpectomy and mastectomy surgeries. Images were compared to post-operative histopathology for diagnosis. OCT images with micron scale resolution show areas of heterogeneity and disorganized features indicative of malignancy, compared to more uniform regions of normal tissue. Video-rate acquisition shows the inside of the tumor cavity as the surgeon sweeps the probe along the walls of the surgical cavity. This demonstrates the potential of OCT for real-time assessment of surgical tumor margins and for reducing the unacceptably high re-operation rate for breast cancer patients.

  10. Advances in probing the blood vessels of the human brain using magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Haacke, E. Mark

    2002-03-01

    Magnetic resonance imaging offers a marvelous means to probe the vasculature of the human body non-invasively. The first major advances came when the physics of the effects of motion in MRI were first understood well enough that new methods could be designed to compensate for the motion. This led to the development of MR angiography. The second major advance occurred when a contrast agent was used to enhance the signal from vessels independent of blood flow. This made it possible to image much smaller vessels because of the increased signal-to-noise ratio. The third major advance occurred when the susceptibility of the venous blood was used to create a new contrast unique to veins even in the presence of the contrast agent to enhance their signal. The fourth advance is close behind with the potential to use the susceptibility to measure the local oxygen content. Each of these advances involved some interesting physics and raised questions about local magnetic field effects, some of which remain unanswered yet today. We will show results from the first three levels with hints at how to proceed to the fourth. The development of this technology has important clinical implications. With new higher relaxivity contrast agents and higher field magnets coming on the market, the possibility to image vessels down to on the order of 100 microns may be viable. Each advance has enhanced the range of applications from just imaging vessels to occult vascular disease, trauma, the detection of blood products, and physiologic function of the tissue itself.

  11. Dual-Labeled Near-Infrared/(99m)Tc Imaging Probes Using PAMAM-Coated Silica Nanoparticles for the Imaging of HER2-Expressing Cancer Cells.

    PubMed

    Yamaguchi, Haruka; Tsuchimochi, Makoto; Hayama, Kazuhide; Kawase, Tomoyuki; Tsubokawa, Norio

    2016-01-01

    We sought to develop dual-modality imaging probes using functionalized silica nanoparticles to target human epidermal growth factor receptor 2 (HER2)-overexpressing breast cancer cells and achieve efficient target imaging of HER2-expressing tumors. Polyamidoamine-based functionalized silica nanoparticles (PCSNs) for multimodal imaging were synthesized with near-infrared (NIR) fluorescence (indocyanine green (ICG)) and technetium-99m ((99m)Tc) radioactivity. Anti-HER2 antibodies were bound to the labeled PCSNs. These dual-imaging probes were tested to image HER2-overexpressing breast carcinoma cells. In vivo imaging was also examined in breast tumor xenograft models in mice. SK-BR3 (HER2 positive) cells were imaged with stronger NIR fluorescent signals than that in MDA-MB231 (HER2 negative) cells. The increased radioactivity of the SK-BR3 cells was also confirmed by phosphor imaging. NIR images showed strong fluorescent signals in the SK-BR3 tumor model compared to muscle tissues and the MDA-MB231 tumor model. Automatic well counting results showed increased radioactivity in the SK-BR3 xenograft tumors. We developed functionalized silica nanoparticles loaded with (99m)Tc and ICG for the targeting and imaging of HER2-expressing cells. The dual-imaging probes efficiently imaged HER2-overexpressing cells. Although further studies are needed to produce efficient isotope labeling, the results suggest that the multifunctional silica nanoparticles are a promising vehicle for imaging specific components of the cell membrane in a dual-modality manner. PMID:27399687

  12. Dual-Labeled Near-Infrared/99mTc Imaging Probes Using PAMAM-Coated Silica Nanoparticles for the Imaging of HER2-Expressing Cancer Cells

    PubMed Central

    Yamaguchi, Haruka; Tsuchimochi, Makoto; Hayama, Kazuhide; Kawase, Tomoyuki; Tsubokawa, Norio

    2016-01-01

    We sought to develop dual-modality imaging probes using functionalized silica nanoparticles to target human epidermal growth factor receptor 2 (HER2)-overexpressing breast cancer cells and achieve efficient target imaging of HER2-expressing tumors. Polyamidoamine-based functionalized silica nanoparticles (PCSNs) for multimodal imaging were synthesized with near-infrared (NIR) fluorescence (indocyanine green (ICG)) and technetium-99m (99mTc) radioactivity. Anti-HER2 antibodies were bound to the labeled PCSNs. These dual-imaging probes were tested to image HER2-overexpressing breast carcinoma cells. In vivo imaging was also examined in breast tumor xenograft models in mice. SK-BR3 (HER2 positive) cells were imaged with stronger NIR fluorescent signals than that in MDA-MB231 (HER2 negative) cells. The increased radioactivity of the SK-BR3 cells was also confirmed by phosphor imaging. NIR images showed strong fluorescent signals in the SK-BR3 tumor model compared to muscle tissues and the MDA-MB231 tumor model. Automatic well counting results showed increased radioactivity in the SK-BR3 xenograft tumors. We developed functionalized silica nanoparticles loaded with 99mTc and ICG for the targeting and imaging of HER2-expressing cells. The dual-imaging probes efficiently imaged HER2-overexpressing cells. Although further studies are needed to produce efficient isotope labeling, the results suggest that the multifunctional silica nanoparticles are a promising vehicle for imaging specific components of the cell membrane in a dual-modality manner. PMID:27399687

  13. Fluorenyl benzothiadiazole and benzoselenadiazole near-IR fluorescent probes for two-photon fluorescence imaging (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Belfield, Kevin D.; Yao, Sheng; Kim, Bosung; Yue, Xiling

    2016-03-01

    Imaging biological samples with two-photon fluorescence (2PF) microscopy has the unique advantage of resulting high contrast 3D resolution subcellular image that can reach up to several millimeters depth. 2PF probes that absorb and emit at near IR region need to be developed. Two-photon excitation (2PE) wavelengths are less concerned as 2PE uses wavelengths doubles the absorption wavelength of the probe, which means 2PE wavelengths for probes even with absorption at visible wavelength will fall into NIR region. Therefore, probes that fluoresce at near IR region with high quantum yields are needed. A series of dyes based on 5-thienyl-2, 1, 3-benzothiadiazole and 5-thienyl-2, 1, 3-benzoselenadiazole core were synthesized as near infrared two-photon fluorophores. Fluorescence maxima wavelengths as long as 714 nm and fluorescence quantum yields as high as 0.67 were achieved. The fluorescence quantum yields of the dyes were nearly constant, regardless of solvents polarity. These diazoles exhibited large Stokes shift (<114nm), high two-photon absorption cross sections (up to 2,800 GM), and high two-photon fluorescence figure of merit (FM , 1.04×10-2 GM). Cells incubated on a 3D scaffold with one of the new probes (encapsulated in Pluronic micelles) exhibited bright fluorescence, enabling 3D two-photon fluorescence imaging to a depth of 100 µm.

  14. In vivo imaging and detection of nitroreductase in zebrafish by a new near-infrared fluorescence off-on probe.

    PubMed

    Li, Zhao; He, Xinyuan; Wang, Zhe; Yang, Ronghua; Shi, Wen; Ma, Huimin

    2015-01-15

    A new near-infrared fluorescence off-on probe is developed and applied to fluorescence imaging of nitroreductase in zebrafish in vivo. The probe is readily prepared by connecting 4-nitrobenzene as a quenching and recognizing moiety to a stable hemicyanine skeleton that can be formed via the decomposition of IR 780. The fluorescence off-on response of the probe to nitroreductase is based on the enzyme-catalyzed reduction of the 4-nitrobenzene moiety, followed by the 1,6-rearrangement-elimination and the fluorophore release. Compared with the existing nitroreductase probes, the proposed probe exhibits superior analytical performance such as near-infrared fluorescence emission over 700 nm as well as high selectivity and sensitivity, with a detection limit of 14 ng/mL. More importantly, the probe has been successfully applied to visualize the distribution of nitroreductase in living zebrafish in vivo, revealing that nitroreductase might mainly exist in zebrafish yolk sac. The superior properties of the probe make it of great potential use in other biosystems and in vivo studies.

  15. A Ratiometric Fluorescent Probe Based on a Through-Bond Energy Transfer (TBET) System for Imaging HOCl in Living Cells.

    PubMed

    Zhang, Yan-Ru; Meng, Ning; Miao, Jun-Ying; Zhao, Bao-Xiang

    2015-12-21

    A simple ratiometric probe (Naph-Rh) has been designed and synthesized based on a through-bond energy transfer (TBET) system for sensing HOCl. In this probe, rhodamine thiohydrazide and naphthalene formyl were connected by simple synthesis methods to construct a structure of monothio-bishydrazide. Free probe Naph-Rh showed only the emission of naphthalene. When probe Naph-Rh reacted with HOCl, monothio-bishydrazide could be converted into 1,2,4-oxadiazole, which not only ensured that the donor and the acceptor were connected with electronically conjugated bonds, but also resulted in the spiro-ring opening and the emission of rhodamine. Therefore, a typical TBET process took place. The probe possessed high-energy transfer efficiency and large pseudo-Stokes shifts. As the first TBET probe for HOCl, Naph-Rh showed excellent selectivity and sensitivity toward HOCl over other reactive oxygen species (ROS)/reactive nitrogen species (RNS), and could respond fast to a low concentration of HOCl in the real sample. In addition, the probe was suitable for imaging HOCl in living cells due to its real-time response, excellent resolution, and reduced cytotoxicity. PMID:26568524

  16. Rational chemical design of the next generation of molecular imaging probes based on physics and biology: mixing modalities, colors and signals

    PubMed Central

    Longmire, Michelle R.; Ogawa, Mikako; Choyke, Peter L.

    2012-01-01

    In recent years, numerous in vivo molecular imaging probes have been developed. As a consequence, much has been published on the design and synthesis of molecular imaging probes focusing on each modality, each type of material, or each target disease. More recently, second generation molecular imaging probes with unique, multi-functional, or multiplexed characteristics have been designed. This critical review focuses on (i) molecular imaging using combinations of modalities and signals that employ the full range of the electromagnetic spectra, (ii) optimized chemical design of molecular imaging probes for in vivo kinetics based on biology and physiology across a range of physical sizes, (iii) practical examples of second generation molecular imaging probes designed to extract complementary data from targets using multiple modalities, color, and comprehensive signals (277 references). PMID:21607237

  17. Rational chemical design of the next generation of molecular imaging probes based on physics and biology: mixing modalities, colors and signals.

    PubMed

    Kobayashi, Hisataka; Longmire, Michelle R; Ogawa, Mikako; Choyke, Peter L

    2011-09-01

    In recent years, numerous in vivo molecular imaging probes have been developed. As a consequence, much has been published on the design and synthesis of molecular imaging probes focusing on each modality, each type of material, or each target disease. More recently, second generation molecular imaging probes with unique, multi-functional, or multiplexed characteristics have been designed. This critical review focuses on (i) molecular imaging using combinations of modalities and signals that employ the full range of the electromagnetic spectra, (ii) optimized chemical design of molecular imaging probes for in vivo kinetics based on biology and physiology across a range of physical sizes, (iii) practical examples of second generation molecular imaging probes designed to extract complementary data from targets using multiple modalities, color, and comprehensive signals (277 references).

  18. Sets of RNA Repeated Tags and Hybridization-Sensitive Fluorescent Probes for Distinct Images of RNA in a Living Cell

    PubMed Central

    Kubota, Takeshi; Ikeda, Shuji; Yanagisawa, Hiroyuki; Yuki, Mizue; Okamoto, Akimitsu

    2010-01-01

    Background Imaging the behavior of RNA in a living cell is a powerful means for understanding RNA functions and acquiring spatiotemporal information in a single cell. For more distinct RNA imaging in a living cell, a more effective chemical method to fluorescently label RNA is now required. In addition, development of the technology labeling with different colors for different RNA would make it easier to analyze plural RNA strands expressing in a cell. Methodology/Principal Findings Tag technology for RNA imaging in a living cell has been developed based on the unique chemical functions of exciton-controlled hybridization-sensitive oligonucleotide (ECHO) probes. Repetitions of selected 18-nucleotide RNA tags were incorporated into the mRNA 3′-UTR. Pairs with complementary ECHO probes exhibited hybridization-sensitive fluorescence emission for the mRNA expressed in a living cell. The mRNA in a nucleus was detected clearly as fluorescent puncta, and the images of the expression of two mRNAs were obtained independently and simultaneously with two orthogonal tag–probe pairs. Conclusions/Significance A compact and repeated label has been developed for RNA imaging in a living cell, based on the photochemistry of ECHO probes. The pairs of an 18-nt RNA tag and the complementary ECHO probes are highly thermostable, sequence-specifically emissive, and orthogonal to each other. The nucleotide length necessary for one tag sequence is much shorter compared with conventional tag technologies, resulting in easy preparation of the tag sequences with a larger number of repeats for more distinct RNA imaging. PMID:20885944

  19. Hydrogen peroxide-activatable antioxidant prodrug as a targeted therapeutic agent for ischemia-reperfusion injury

    PubMed Central

    Lee, Dongwon; Park, Seunggyu; Bae, Soochan; Jeong, Dahee; Park, Minhyung; Kang, Changsun; Yoo, Wooyoung; Samad, Mohammed A.; Ke, Qingen; Khang, Gilson; Kang, Peter M.

    2015-01-01

    Overproduction of hydrogen peroxide (H2O2) causes oxidative stress and is the main culprit in the pathogenesis of ischemia/reperfusion (I/R) injury. Suppression of oxidative stress is therefore critical in the treatment of I/R injury. Here, we report H2O2-activatable antioxidant prodrug (BRAP) that is capable of specifically targeting the site of oxidative stress and exerting anti-inflammatory and anti-apoptotic activities. BRAP with a self-immolative boronic ester protecting group was designed to scavenge H2O2 and release HBA (p-hydroxybenzyl alcohol) with antioxidant and anti-inflammatory activities. BRAP exerted potent antioxidant and anti-inflammatory activity in lipopolysaccharide (LPS)- and H2O2-stimulated cells by suppressing the generation of ROS and pro-inflammatory cytokines. In mouse models of hepatic I/R and cardiac I/R, BRAP exerted potent antioxidant, anti-inflammatory and anti-apoptotic activities due to the synergistic effects of H2O2-scavenging boronic esters and therapeutic HBA. In addition, administration of high doses of BRAP daily for 7 days showed no renal or hepatic function abnormalities. Therefore BRAP has tremendous therapeutic potential as H2O2-activatable antioxidant prodrug for the treatment of I/R injuries. PMID:26563741

  20. Hydrogen peroxide-activatable antioxidant prodrug as a targeted therapeutic agent for ischemia-reperfusion injury.

    PubMed

    Lee, Dongwon; Park, Seunggyu; Bae, Soochan; Jeong, Dahee; Park, Minhyung; Kang, Changsun; Yoo, Wooyoung; Samad, Mohammed A; Ke, Qingen; Khang, Gilson; Kang, Peter M

    2015-11-13

    Overproduction of hydrogen peroxide (H2O2) causes oxidative stress and is the main culprit in the pathogenesis of ischemia/reperfusion (I/R) injury. Suppression of oxidative stress is therefore critical in the treatment of I/R injury. Here, we report H2O2-activatable antioxidant prodrug (BRAP) that is capable of specifically targeting the site of oxidative stress and exerting anti-inflammatory and anti-apoptotic activities. BRAP with a self-immolative boronic ester protecting group was designed to scavenge H2O2 and release HBA (p-hydroxybenzyl alcohol) with antioxidant and anti-inflammatory activities. BRAP exerted potent antioxidant and anti-inflammatory activity in lipopolysaccharide (LPS)- and H2O2-stimulated cells by suppressing the generation of ROS and pro-inflammatory cytokines. In mouse models of hepatic I/R and cardiac I/R, BRAP exerted potent antioxidant, anti-inflammatory and anti-apoptotic activities due to the synergistic effects of H2O2-scavenging boronic esters and therapeutic HBA. In addition, administration of high doses of BRAP daily for 7 days showed no renal or hepatic function abnormalities. Therefore BRAP has tremendous therapeutic potential as H2O2-activatable antioxidant prodrug for the treatment of I/R injuries.

  1. Combination probe for optically assisted ultrasonic velocity-change imaging aimed at detecting unstable blood vessel plaque

    NASA Astrophysics Data System (ADS)

    Tanigawa, Shohei; Mano, Kazune; Wada, Kenji; Matsunaka, Toshiyuki; Horinaka, Hiromichi

    2016-04-01

    Blood vessel plaque with a large lipid core is at risk of becoming thrombus and is likely to induce acute heart disease. To prevent this, it is necessary to determine not only the plaque's size but also its chemical composition. We, therefore, made the prototype of a combination probe to diagnose carotid artery plaque. It is used to differentiate propagation characteristics between light spectra and ultrasonic images. By propagating light and ultrasound along a common direction, it is possible to effectively warm the diagnosis domain. Moreover, the probe is thought to be compact and be easy to use for diagnosing human carotid artery plaque. We applied the combination probe to a carotid artery phantom with a lipid area and obtained an image of the ultrasonic velocity change in the fatty area.

  2. Cancer cell-targeted two-photon fluorescence probe for the real-time ratiometric imaging of DNA damage.

    PubMed

    Zhang, Hua; Wang, Kui; Xuan, Xiaopeng; Lv, Qingzhang; Nie, Yamin; Guo, Haiming

    2016-05-01

    Real-time imaging of DNA damage in cancer cells could provide valuable information on the formation and development of cancer. Herein, a two-photon fluorescence probe was discovered. Through sequential ICT processes, it allows successful in vivo visualization of DNA damage in cancer cells by one/two-photon microscopic imaging or by the unaided eye and a hand-held ultraviolet lamp. PMID:27087314

  3. A hot tip: imaging phenomena using in situ multi-stimulus probes at high temperatures.

    PubMed

    Nonnenmann, Stephen S

    2016-02-14

    Accurate high temperature characterization of materials remains a critical challenge to the continued advancement of various important energy, nuclear, electronic, and aerospace applications. Future experimental studies must assist these communities to progress past empiricism and derive deliberate, predictable designs of material classes functioning within active, extreme environments. Successful realization of systems ranging from fuel cells and batteries to electromechanical nanogenerators and turbines requires a dynamic understanding of the excitation, surface-mediated, and charge transfer phenomena which occur at heterophase interfaces (i.e. vapor-solid, liquid-solid, solid-solid) and impact overall performance. Advancing these frontiers therefore necessitates in situ (operando) characterization methods capable of resolving, both spatially and functionally, the coherence between these complex, collective excitations, and their respective response dynamics, through studies within the operating regime. This review highlights recent developments in scanning probe microscopy in performing in situ imaging at high elevated temperatures. The influence of and evolution from vacuum-based electron and tunneling microscopy are briefly summarized and discussed. The scope includes the use of high temperature imaging to directly observe critical phase transition, electronic, and electrochemical behavior under dynamic temperature settings, thus providing key physical parameters. Finally, both challenges and directions in combined instrumentation are proposed and discussed towards the end.

  4. A hot tip: imaging phenomena using in situ multi-stimulus probes at high temperatures

    NASA Astrophysics Data System (ADS)

    Nonnenmann, Stephen S.

    2016-02-01

    Accurate high temperature characterization of materials remains a critical challenge to the continued advancement of various important energy, nuclear, electronic, and aerospace applications. Future experimental studies must assist these communities to progress past empiricism and derive deliberate, predictable designs of material classes functioning within active, extreme environments. Successful realization of systems ranging from fuel cells and batteries to electromechanical nanogenerators and turbines requires a dynamic understanding of the excitation, surface-mediated, and charge transfer phenomena which occur at heterophase interfaces (i.e. vapor-solid, liquid-solid, solid-solid) and impact overall performance. Advancing these frontiers therefore necessitates in situ (operando) characterization methods capable of resolving, both spatially and functionally, the coherence between these complex, collective excitations, and their respective response dynamics, through studies within the operating regime. This review highlights recent developments in scanning probe microscopy in performing in situ imaging at high elevated temperatures. The influence of and evolution from vacuum-based electron and tunneling microscopy are briefly summarized and discussed. The scope includes the use of high temperature imaging to directly observe critical phase transition, electronic, and electrochemical behavior under dynamic temperature settings, thus providing key physical parameters. Finally, both challenges and directions in combined instrumentation are proposed and discussed towards the end.

  5. Scanning probe microscopy beyond imaging: a general tool for quantitative analysis.

    PubMed

    Liscio, Andrea

    2013-04-15

    A simple, fast and general approach for quantitative analysis of scanning probe microscopy (SPM) images is reported. As a proof of concept it is used to determine with a high degree of precision the value of observables such as 1) the height, 2) the flowing current and 3) the corresponding surface potential (SP) of flat nanostructures such as gold electrodes, organic semiconductor architectures and graphenic sheets. Despite histogram analysis, or frequency count (Fc), being the most common mathematical tool used to analyse SPM images, the analytical approach is still lacking. By using the mathematical relationship between Fc and the collected data, the proposed method allows quantitative information on observable values close to the noise level to be gained. For instance, the thickness of nanostructures deposited on very rough substrates can be quantified, and this makes it possible to distinguish the contribution of an adsorbed nanostructure from that of the underlying substrate. Being non-numerical, this versatile analytical approach is a useful and general tool for quantitative analysis of the Fc that enables all signals acquired and recorded by an SPM data array to be studied with high precision.

  6. A new approach to the interpretation of atom probe field-ion microscopy images.

    PubMed

    Vurpillot, F; Bostel, A; Blavette, D

    2001-10-01

    The field distribution and the ion trajectories close to the tip surface are known to mainly control the contrast of field-ion microscopy and the resolution of the three-dimensional atom probe. The proper interpretation of images provided by these techniques requires the electric field and the ion trajectories to be determined accurately. A model has been developed in order to compute the ion trajectories close to a curved emitting surface modelled at the atomic scale. In this model, both the gradual change of the tip surface and the chemical nature of atoms were taken into account. Predictions and results given by this approach are shown to be in excellent agreement with experiments. The calculated electric field at the tip surface is consistent with field-ion microscopy contrasts. The preferential retention of surface atoms and the order of evaporation were correctly simulated. The ion trajectories were successfully described. In this way, the crucial problem of trajectory overlap and local magnification could be investigated. These simulations not only lead to a new understanding of the physical basis of image formation, but also have a predictive value.

  7. Probing the spin of the central black hole in the Galactic Centre with secondary images

    NASA Astrophysics Data System (ADS)

    Jørgensen, Jonas Helboe; Bjælde, Ole Eggers; Hannestad, Steen

    2016-06-01

    This paper explores the possibility of determining the spin of the supermassive black hole (SMBH) in Sgr A* by using secondary images of stars orbiting the SMBH. The photons propagate close to the SMBH and their trajectories probe the space-time in a region where the spin of the SMBH is important. We find the appearance of spikes in the secondary image, which depends on the angular momentum and spin axis of the SMBH and study the specific case of the star S2 in detail. The spikes have a magnitude of ˜29 in the K band and the required angular resolution is of the order of 15-20 μas. The combination of these two requirements poses an extreme observational challenge, but might be possible with interferometric observations in the sub-mm regime. The next possible time frame for observing this effect on the star S2 is in the late 2017 and then it repeats with the period of the star.

  8. Two-Photon Lifetime Imaging of Voltage Indicating Proteins as a Probe of Absolute Membrane Voltage.

    PubMed

    Brinks, Daan; Klein, Aaron J; Cohen, Adam E

    2015-09-01

    Genetically encoded voltage indicators (GEVIs) can report cellular electrophysiology with high resolution in space and time. Two-photon (2P) fluorescence has been explored as a means to image voltage in tissue. Here, we used the 2P electronic excited-state lifetime to probe absolute membrane voltage in a manner that is insensitive to the protein expression level, illumination intensity, or photon detection efficiency. First, we tested several GEVIs for 2P brightness, response speed, and voltage sensitivity. ASAP1 and a previously described citrine-Arch electrochromic Förster resonance energy transfer sensor (dubbed CAESR) showed the best characteristics. We then characterized the voltage-dependent lifetime of ASAP1, CAESR, and ArcLight under voltage-clamp conditions. ASAP1 and CAESR showed voltage-dependent lifetimes, whereas ArcLight did not. These results establish 2P fluorescence lifetime imaging as a viable means of measuring absolute membrane voltage. We discuss the prospects and improvements necessary for applications in tissue.

  9. Serum Albumin Binding Inhibits Nuclear Uptake of Luminescent Metal-Complex-Based DNA Imaging Probes.

    PubMed

    Wragg, Ashley; Gill, Martin R; McKenzie, Luke; Glover, Caroline; Mowll, Rachel; Weinstein, Julia A; Su, Xiaodi; Smythe, Carl; Thomas, Jim A

    2015-08-10

    The DNA binding and cellular localization properties of a new luminescent heterobimetallic Ir(III) Ru(II) tetrapyridophenazine complex are reported. Surprisingly, in standard cell media, in which its tetracationic, isostructural Ru(II) Ru(II) analogue is localized in the nucleus, the new tricationic complex is poorly taken up by live cells and demonstrates no nuclear staining. Consequent cell-free studies reveal that the Ir(III) Ru(II) complex binds bovine serum albumin, BSA, in Sudlow's Site I with a similar increase in emission and binding affinity to that observed with DNA. Contrastingly, in serum-free conditions the complex is rapidly internalized by live cells, where it localizes in cell nuclei and functions as a DNA imaging agent. The absence of serum proteins also greatly alters the cytotoxicity of the complex, where high levels of oncosis/necrosis are observed due to this enhanced uptake. This suggests that simply increasing the lipophilicity of a DNA imaging probe to enhance cellular uptake can be counterproductive as, due to increased binding to serum albumin protein, this strategy can actually disrupt nuclear targeting.

  10. Atomic force microscopy deep trench and sidewall imaging with an optical fiber probe

    SciTech Connect

    Xie, Hui Hussain, Danish; Yang, Feng; Sun, Lining

    2014-12-15

    We report a method to measure critical dimensions of micro- and nanostructures using the atomic force microscope (AFM) with an optical fiber probe (OFP). This method is capable of scanning narrow and deep trenches due to the long and thin OFP tip, as well as imaging of steep sidewalls with unique profiling possibilities by laterally tilting the OFP without any modifications of the optical lever. A switch control scheme is developed to measure the sidewall angle by flexibly transferring feedback control between the Z- and Y-axis, for a serial scan of the horizontal surface (raster scan on XY-plane) and sidewall (raster scan on the YZ-plane), respectively. In experiments, a deep trench with tapered walls (243.5 μm deep) and a microhole (about 14.9 μm deep) have been imaged with the orthogonally aligned OFP, as well as a silicon sidewall (fabricated by deep reactive ion etching) has been characterized with the tilted OFP. Moreover, the sidewall angle of TGZ3 (AFM calibration grating) was accurately measured using the switchable scan method.

  11. Two-Photon Lifetime Imaging of Voltage Indicating Proteins as a Probe of Absolute Membrane Voltage.

    PubMed

    Brinks, Daan; Klein, Aaron J; Cohen, Adam E

    2015-09-01

    Genetically encoded voltage indicators (GEVIs) can report cellular electrophysiology with high resolution in space and time. Two-photon (2P) fluorescence has been explored as a means to image voltage in tissue. Here, we used the 2P electronic excited-state lifetime to probe absolute membrane voltage in a manner that is insensitive to the protein expression level, illumination intensity, or photon detection efficiency. First, we tested several GEVIs for 2P brightness, response speed, and voltage sensitivity. ASAP1 and a previously described citrine-Arch electrochromic Förster resonance energy transfer sensor (dubbed CAESR) showed the best characteristics. We then characterized the voltage-dependent lifetime of ASAP1, CAESR, and ArcLight under voltage-clamp conditions. ASAP1 and CAESR showed voltage-dependent lifetimes, whereas ArcLight did not. These results establish 2P fluorescence lifetime imaging as a viable means of measuring absolute membrane voltage. We discuss the prospects and improvements necessary for applications in tissue. PMID:26331249

  12. A hot tip: imaging phenomena using in situ multi-stimulus probes at high temperatures.

    PubMed

    Nonnenmann, Stephen S

    2016-02-14

    Accurate high temperature characterization of materials remains a critical challenge to the continued advancement of various important energy, nuclear, electronic, and aerospace applications. Future experimental studies must assist these communities to progress past empiricism and derive deliberate, predictable designs of material classes functioning within active, extreme environments. Successful realization of systems ranging from fuel cells and batteries to electromechanical nanogenerators and turbines requires a dynamic understanding of the excitation, surface-mediated, and charge transfer phenomena which occur at heterophase interfaces (i.e. vapor-solid, liquid-solid, solid-solid) and impact overall performance. Advancing these frontiers therefore necessitates in situ (operando) characterization methods capable of resolving, both spatially and functionally, the coherence between these complex, collective excitations, and their respective response dynamics, through studies within the operating regime. This review highlights recent developments in scanning probe microscopy in performing in situ imaging at high elevated temperatures. The influence of and evolution from vacuum-based electron and tunneling microscopy are briefly summarized and discussed. The scope includes the use of high temperature imaging to directly observe critical phase transition, electronic, and electrochemical behavior under dynamic temperature settings, thus providing key physical parameters. Finally, both challenges and directions in combined instrumentation are proposed and discussed towards the end. PMID:26795921

  13. Super-Resolution Dynamic Imaging of Dendritic Spines Using a Low-Affinity Photoconvertible Actin Probe

    PubMed Central

    Lelek, Mickaël; Darzacq, Xavier; Triller, Antoine; Zimmer, Christophe; Dahan, Maxime

    2011-01-01

    The actin cytoskeleton of dendritic spines plays a key role in morphological aspects of synaptic plasticity. The detailed analysis of the spine structure and dynamics in live neurons, however, has been hampered by the diffraction-limited resolution of conventional fluorescence microscopy. The advent of nanoscopic imaging techniques thus holds great promise for the study of these processes. We implemented a strategy for the visualization of morphological changes of dendritic spines over tens of minutes at a lateral resolution of 25 to 65 nm. We have generated a low-affinity photoconvertible probe, capable of reversibly binding to actin and thus allowing long-term photoactivated localization microscopy of the spine cytoskeleton. Using this approach, we resolve structural parameters of spines and record their long-term dynamics at a temporal resolution below one minute. Furthermore, we have determined changes in the spine morphology in response to pharmacologically induced synaptic activity and quantified the actin redistribution underlying these changes. By combining PALM imaging with quantum dot tracking, we could also simultaneously visualize the cytoskeleton and the spine membrane, allowing us to record complementary information on the morphological changes of the spines at super-resolution. PMID:21264214

  14. Validation of break-apart and fusion MYC probes using a digital fluorescence in situ hybridization capture and imaging system

    PubMed Central

    Liew, Michael; Rowe, Leslie; Clement, Parker W.; Miles, Rodney R.; Salama, Mohamed E.

    2016-01-01

    Introduction: Detection of MYC translocations using fluorescence in situ hybridization (FISH) is important in the evaluation of lymphomas, in particular, Burkitt lymphoma and diffuse large B-cell lymphoma. Our aim was to validate a digital FISH capture and imaging system for the detection of MYC 8q24 translocations using LSI-MYC (a break-apart probe) and MYC 8;14 translocation using IGH-MYC (a fusion probe). Materials and Methods: LSI-MYC probe was evaluated using tissue sections from 35 patients. IGH-MYC probe was evaluated using tissue sections from forty patients. Sections were processed for FISH and analyzed using traditional methods. FISH slides were then analyzed using the GenASIs capture and analysis system. Results: Results for LSI-MYC had a high degree of correlation between traditional method of FISH analysis and digital FISH analysis. Results for IGH-MYC had a 100% concordance between traditional method of FISH analysis and digital FISH analysis. Conclusion: Annotated whole slide images of H and E and FISH sections can be digitally aligned, so that areas of tumor within a section can be matched and evaluated with a greater degree of accuracy. Images can be archived permanently, providing a means for examining the results retrospectively. Digital FISH imaging of the MYC translocations provides a better diagnostic tool compared to traditional methods for evaluating lymphomas. PMID:27217970

  15. Probing the functions of contextual modulation by adapting images rather than observers

    PubMed Central

    Webster, Michael A.

    2014-01-01

    Countless visual aftereffects have illustrated how visual sensitivity and perception can be biased by adaptation to the recent temporal context. This contextual modulation has been proposed to serve a variety of functions, but the actual benefits of adaptation remain uncertain. We describe an approach we have recently developed for exploring these benefits by adapting images instead of observers, to simulate how images should appear under theoretically optimal states of adaptation. This allows the long-term consequences of adaptation to be evaluated in ways that are difficult to probe by adapting observers, and provides a common framework for understanding how visual coding changes when the environment or the observer changes, or for evaluating how the effects of temporal context depend on different models of visual coding or the adaptation processes. The approach is illustrated for the specific case of adaptation to color, for which the initial neural coding and adaptation processes are relatively well understood, but can in principle be applied to examine the consequences of adaptation for any stimulus dimension. A simple calibration that adjusts each neuron’s sensitivity according to the stimulus level it is exposed to is sufficient to normalize visual coding and generate a host of benefits, from increased efficiency to perceptual constancy to enhanced discrimination. This temporal normalization may also provide an important precursor for the effective operation of contextual mechanisms operating across space or feature dimensions. To the extent that the effects of adaptation can be predicted, images from new environments could be “pre-adapted” to match them to the observer, eliminating the need for observers to adapt. PMID:25281412

  16. Fluorescence lifetime imaging of membrane lipid order with a ratiometric fluorescent probe.

    PubMed

    Kilin, Vasyl; Glushonkov, Oleksandr; Herdly, Lucas; Klymchenko, Andrey; Richert, Ludovic; Mely, Yves

    2015-05-19

    To monitor the lateral segregation of lipids into liquid-ordered (Lo) and -disordered (Ld) phases in lipid membranes, environment-sensitive dyes that partition in both phases but stain them differently have been developed. Of particular interest is the dual-color F2N12S probe, which can discriminate the two phases through the ratio of its two emission bands. These bands are associated with the normal (N(∗)) and tautomer (T(∗)) excited-state species that result from an excited-state intramolecular proton transfer. In this work, we investigated the potency of the time-resolved fluorescence parameters of F2N12S to discriminate lipid phases in model and cell membranes. Both the long and mean lifetime values of the T(∗) form of F2N12S were found to differ by twofold between Ld and Lo phases as a result of the restriction in the relative motions of the two aromatic moieties of F2N12S imposed by the highly packed Lo phase. This differed from the changes in the ratio of the two emission bands between the two phases, which mainly resulted from the decreased hydration of the N(∗) form in the Lo phase. Importantly, the strong difference in lifetimes between the two phases was preserved when cholesterol was added to the Ld phase. The two phases could be imaged with high contrast by fluorescence lifetime imaging microscopy (FLIM) on giant unilamellar vesicles. FLIM images of F2N12S-labeled live HeLa cells confirmed that the plasma membrane was mainly in the Lo-like phase. Furthermore, the two phases were found to be homogeneously distributed all over the plasma membrane, indicating that they are highly mixed at the spatiotemporal resolution of the FLIM setup. Finally, FLIM could also be used to sensitively monitor the change in lipid phase upon cholesterol depletion and apoptosis. PMID:25992730

  17. Fluorescence Lifetime Imaging of Membrane Lipid Order with a Ratiometric Fluorescent Probe

    PubMed Central

    Kilin, Vasyl; Glushonkov, Oleksandr; Herdly, Lucas; Klymchenko, Andrey; Richert, Ludovic; Mely, Yves

    2015-01-01

    To monitor the lateral segregation of lipids into liquid-ordered (Lo) and -disordered (Ld) phases in lipid membranes, environment-sensitive dyes that partition in both phases but stain them differently have been developed. Of particular interest is the dual-color F2N12S probe, which can discriminate the two phases through the ratio of its two emission bands. These bands are associated with the normal (N∗) and tautomer (T∗) excited-state species that result from an excited-state intramolecular proton transfer. In this work, we investigated the potency of the time-resolved fluorescence parameters of F2N12S to discriminate lipid phases in model and cell membranes. Both the long and mean lifetime values of the T∗ form of F2N12S were found to differ by twofold between Ld and Lo phases as a result of the restriction in the relative motions of the two aromatic moieties of F2N12S imposed by the highly packed Lo phase. This differed from the changes in the ratio of the two emission bands between the two phases, which mainly resulted from the decreased hydration of the N∗ form in the Lo phase. Importantly, the strong difference in lifetimes between the two phases was preserved when cholesterol was added to the Ld phase. The two phases could be imaged with high contrast by fluorescence lifetime imaging microscopy (FLIM) on giant unilamellar vesicles. FLIM images of F2N12S-labeled live HeLa cells confirmed that the plasma membrane was mainly in the Lo-like phase. Furthermore, the two phases were found to be homogeneously distributed all over the plasma membrane, indicating that they are highly mixed at the spatiotemporal resolution of the FLIM setup. Finally, FLIM could also be used to sensitively monitor the change in lipid phase upon cholesterol depletion and apoptosis. PMID:25992730

  18. Imaging the distribution of photoswitchable probes with temporally-unmixed multispectral optoacoustic tomography

    NASA Astrophysics Data System (ADS)

    Deán-Ben, X. Luís.; Stiel, Andre C.; Jiang, Yuanyuan; Ntziachristos, Vasilis; Westmeyer, Gil G.; Razansky, Daniel

    2016-03-01

    Synthetic and genetically encoded chromo- and fluorophores have become indispensable tools for biomedical research enabling a myriad of applications in imaging modalities based on biomedical optics. The versatility offered by the optoacoustic (photoacoustic) contrast mechanism enables to detect signals from any substance absorbing light, and hence these probes can be used as optoacoustic contrast agents. While contrast versatility generally represents an advantage of optoacoustics, the strong background signal generated by light absorption in endogeneous chromophores hampers the optoacoustic capacity to detect a photo-absorbing agent of interest. Increasing the optoacoustic sensitivity is then determined by the capability to differentiate specific features of such agent. For example, multispectral optoacoustic tomography (MSOT) exploits illuminating the tissue at multiple optical wavelengths to spectrally resolve (unmix) the contribution of different chromophores. Herein, we present an alternative approach to enhance the sensitivity and specificity in the detection of optoacoustic contrast agents. This is achieved with photoswitchable probes that change optical absorption upon illumination with specific optical wavelengths. Thereby, temporally unmixed MSOT (tuMSOT) is based on photoswitching the compounds according to defined schedules to elicit specific time-varying optoacoustic signals, and then use temporal unmixing algorithms to locate the contrast agent based on their particular temporal profile. The photoswitching kinetics is further affected by light intensity, so that tuMSOT can be employed to estimate the light fluence distribution in a biological sample. The performance of the method is demonstrated herein with the reversibly switchable fluorescent protein Dronpa and its fast-switching fatigue resistant variant Dronpa-M159T.

  19. Radioisotope guided surgery with imaging probe, a hand-held high-resolution gamma camera

    NASA Astrophysics Data System (ADS)

    Soluri, A.; Trotta, C.; Scopinaro, F.; Tofani, A.; D'Alessandria, C.; Pasta, V.; Stella, S.; Massari, R.

    2007-12-01

    Since 1997, our group of Physics together with Nuclear Physicians studies imaging probes (IP), hand-held, high-resolution gamma cameras for radio-guided surgery (RGS). Present work is aimed to verify the usefulness of two updated IP in different surgical operations. Forty patients scheduled for breast cancer sentinel node (SN) biopsy, five patients with nodal recurrence of thyroid cancer, seven patients with parathyroid adenomas, five patients with neuroendocrine tumours (NET), were operated under the guide of IP. We used two different IP with field of view of 1 and 4 in. 2, respectively and intrinsic spatial resolution of about 2 mm. Radioisotopes were 99mTc, 123I and 111In. The 1 in. 2 IP detected SN in all the 40 patients and more than one node in 24, whereas anger camera (AC) failed locating SN in four patients and detected true positive second nodes in only nine patients. The 4 in. 2 IP was used for RGS of thyroid, parathyroid and NETs. It detected eight latero-cervical nodes. In the same patients, AC detected five invaded nodes. Parathyroid adenomas detected by IP were 10 in 7 patients, NET five in five patients. One and 4 in. 2 IPs showed usefulness in all operations. Initial studies on SN biopsy were carried out on small series of patients to validate IP and to demonstrate the effectiveness and usefulness of IP alone or against conventional probes. We propose the use of the IP as control method for legal documentation and surgeon strategy guide before and after lesion(s) removal.

  20. A Miniature Forward-imaging B-scan Optical Coherence Tomography Probe to Guide Real-time Laser Ablation

    PubMed Central

    Li, Zhuoyan; Shen, Jin H.; Kozub, John A.; Prasad, Ratna; Lu, Pengcheng; Joos, Karen M.

    2014-01-01

    Background and Objective Investigations have shown that pulsed lasers tuned to 6.1 μm in wavelength are capable of ablating ocular and neural tissue with minimal collateral damage. This study investigated whether a miniature B-scan forward-imaging optical coherence tomography (OCT) probe can be combined with the laser to provide real-time visual feedback during laser incisions. Study Design/Methods and Materials A miniature 25-gauge B-scan forward-imaging OCT probe was developed and combined with a 250 μm hollow-glass waveguide to permit delivery of 6.1 μm laser energy. A gelatin mixture and both porcine corneal and retinal tissues were simultaneously imaged and lased (6.1 μm, 10 Hz, 0.4-0.7 mJ) through air. The ablation studies were observed and recorded in real time. The crater dimensions were measured using OCT imaging software (Bioptigen, Durham, NC). Histological analysis was performed on the ocular tissues. Results The combined miniature forward-imaging OCT and mid-infrared laser-delivery probe successfully imaged real-time tissue ablation in gelatin, corneal tissue, and retinal tissue. Application of a constant number of 60 pulses at 0.5 mJ/pulse to the gelatin resulted in a mean crater depth of 123 ± 15 μm. For the corneal tissue, there was a significant correlation between the number of pulses used and depth of the lased hole (Pearson correlation coefficient = 0.82; P = 0.0002). Histological analysis of the cornea and retina tissues showed discrete holes with minimal thermal damage. Conclusions A combined miniature OCT and laser -delivery probe can monitor real-time tissue laser ablation. With additional testing and improvements, this novel instrument has the future possibility of effectively guiding surgeries by simultaneously imaging and ablating tissue. PMID:24648326

  1. Using C-arm x-ray imaging to guide local reporter probe delivery for tracking stem cell engraftment.

    PubMed

    Kedziorek, Dorota A; Solaiyappan, Meiyappan; Walczak, Piotr; Ehtiati, Tina; Fu, Yingli; Bulte, Jeff W M; Shea, Steven M; Brost, Alexander; Wacker, Frank K; Kraitchman, Dara L

    2013-01-01

    Poor cell survival and difficulties with visualization of cell delivery are major problems with current cell transplantation methods. To protect cells from early destruction, microencapsulation methods have been developed. The addition of a contrast agent to the microcapsule also could enable tracking by MR, ultrasound, and X-ray imaging. However, determining the cell viability within the microcapsule still remains an issue. Reporter gene imaging provides a way to determine cell viability, but delivery of the reporter probe by systemic injection may be hindered in ischemic diseases. In the present study, mesenchymal stem cells (MSCs) were transfected with triple fusion reporter gene containing red fluorescent protein, truncated thymidine kinase (SPECT/PET reporter) and firefly luciferase (bioluminescence reporter). Transfected cells were microencapsulated in either unlabeled or perfluorooctylbromide (PFOB) impregnated alginate. The addition of PFOB provided radiopacity to enable visualization of the microcapsules by X-ray imaging. Before intramuscular transplantation in rabbit thigh muscle, the microcapsules were incubated with D-luciferin, and bioluminescence imaging (BLI) was performed immediately. Twenty-four and forty-eight hours post transplantation, c-arm CT was used to target the luciferin to the X-ray-visible microcapsules for BLI cell viability assessment, rather than systemic reporter probe injections. Not only was the bioluminescent signal emission from the PFOB-encapsulated MSCs confirmed as compared to non-encapsulated, naked MSCs, but over 90% of injection sites of PFOB-encapsulated MSCs were visible on c-arm CT. The latter aided in successful targeting of the reporter probe to injection sites using conventional X-ray imaging to determine cell viability at 1-2 days post transplantation. Blind luciferin injections to the approximate location of unlabeled microcapsules resulted in successful BLI signal detection in only 18% of injections. In conclusion

  2. From hand-rotated multiplane transesophageal to fast-rotating parasternal probes for cardiac imaging

    NASA Astrophysics Data System (ADS)

    Bom, Nicolaas; Lancee, Charles T.; de Jong, Nico; van der Steen, Anton F. W.; Roelandt, J. R.

    1999-06-01

    Trans-Esophageal Echocardiographic probes were introduced around 1982. The development ranges over the years from single plane, phased array transducers at low frequency to today's multiplane probes with a large number of elements. Further miniaturization and higher frequencies allow paediatric applications. Recent development includes a probe with 48 elements at 7 MHz with a shaft diameter of only 5 mm.

  3. Transmission Geometry Laser Ablation into a Non-Contact Liquid Vortex Capture Probe for Mass Spectrometry Imaging

    SciTech Connect

    Ovchinnikova, Olga S; Bhandari, Deepak; Lorenz, Matthias; Van Berkel, Gary J

    2014-01-01

    RATIONALE: Capture of material from a laser ablation plume into a continuous flow stream of solvent provides the means for uninterrupted sampling, transport and ionization of collected material for coupling with mass spectral analysis. Reported here is the use of vertically aligned transmission geometry laser ablation in combination with a new non-contact liquid vortex capture probe coupled with electrospray ionization for spot sampling and chemical imaging with mass spectrometry. Methods: A vertically aligned continuous flow liquid vortex capture probe was positioned directly underneath a sample surface in a transmission geometry laser ablation (355 nm, 10 Hz, 7 ns pulse width) setup to capture into solution the ablated material. The outlet of the vortex probe was coupled to the Turbo V ion source of an AB SCIEX TripleTOF 5600+ mass spectrometer. System operation and performance metrics were tested using inked patterns and thin tissue sections. Glass slides and slides designed especially for laser capture microdissection, viz., DIRECTOR slides and PEN 1.0 (polyethylene naphthalate) membrane slides, were used as sample substrates. Results: The estimated capture efficiency of laser ablated material was 24%, which was enabled by the use of a probe with large liquid surface area (~ 2.8 mm2) and with gravity to help direct ablated material vertically down towards the probe. The swirling vortex action of the liquid surface potentially enhanced capture and dissolution of not only particulates, but also gaseous products of the laser ablation. The use of DIRECTOR slides and PEN 1.0 (polyethylene naphthalate) membrane slides as sample substrates enabled effective ablation of a wide range of sample types (basic blue 7, polypropylene glycol, insulin and cyctochrome c) without photodamage using a UV laser. Imaging resolution of about 6 m was demonstrated for stamped ink on DIRECTOR slides based on the ability to distinguish features present both in the optical and in the

  4. Wide-field time-gated photoluminescence microscopy for fast ultrahigh-sensitivity imaging of photoluminescent probes.

    PubMed

    Razali, Wan A W; Sreenivasan, Varun K A; Bradac, Carlo; Connor, Mark; Goldys, Ewa M; Zvyagin, Andrei V

    2016-08-01

    Fluorescence microscopy is a fundamental technique for the life sciences, where biocompatible and photostable photoluminescence probes in combination with fast and sensitive imaging systems are continually transforming this field. A wide-field time-gated photoluminescence microscopy system customised for ultrasensitive imaging of unique nanoruby probes with long photoluminescence lifetime is described. The detection sensitivity derived from the long photoluminescence lifetime of the nanoruby makes it possible to discriminate signals from unwanted autofluorescence background and laser backscatter by employing a time-gated image acquisition mode. This mode enabled several-fold improvement of the photoluminescence imaging contrast of discrete nanorubies dispersed on a coverslip. It enabled recovery of the photoluminescence signal emanating from discrete nanorubies when covered by a layer of an organic fluorescent dye, which were otherwise invisible without the use of spectral filtering approaches. Time-gated imaging also facilitated high sensitivity detection of nanorubies in a biological environment of cultured cells. Finally, we monitor the binding kinetics of nanorubies to a functionalised substrate, which exemplified a real-time assay in biological fluids. 3D-pseudo colour images of nanorubies immersed in a highly fluorescent dye solution. Nanoruby photoluminescence is subdued by that of the dye in continuous excitation/imaging (left), however it can be recovered by time-gated imaging (right). At the bottom is schematic diagram of nanoruby assay in a biological fluid. PMID:27264934

  5. A novel DNA tetrahedron-hairpin probe for in situ"off-on" fluorescence imaging of intracellular telomerase activity.

    PubMed

    Feng, Qiu-Mei; Zhu, Meng-Jiao; Zhang, Ting-Ting; Xu, Jing-Juan; Chen, Hong-Yuan

    2016-04-21

    A novel three-dimensionally structured DNA probe is reported to realize in situ"off-on" imaging of intracellular telomerase activity. The probe consists of a DNA tetrahedron and a hairpin DNA on one of the vertices of the DNA tetrahedron. It is composed of four modified DNA segments: S1-Au nanoparticle (NP) inserting a telomerase strand primer (TSP) and S2-S4, three Cy5 dye modified DNA segments. Fluorescence of Cy5 at three vertices of the DNA tetrahedron is quenched by the Au NP at the other vertex due to the effective fluorescence resonance energy transfer (FRET) ("off" state). When the probe meets telomerase, the hairpin structure changes to rod-like through complementary hybridization with the telomerase-triggered stem elongation product, resulting in a large distance between the Au NP and Cy5 and the recovery of Cy5 fluorescence ("on" state). The molar ratio of 3 : 1 between the reporter (Cy5) and the target related TSP makes the probe show high sensitivity and recovery efficiency of Cy5 in the presence of telomerase extracted from HeLa cells. Given the functional and compact nanostructure, the mechanically stable and noncytotoxic nature of the DNA tetrahedron, this FRET-based probe provides more opportunities for biosensing, molecular imaging and drug delivery.

  6. Multi-parametric imaging of tumor spheroids with ultra-bright and tunable nanoparticle O2 probes

    NASA Astrophysics Data System (ADS)

    Dmitriev, Ruslan I.; Borisov, Sergey M.; Jenkins, James; Papkovsky, Dmitri B.

    2015-03-01

    Multi-modal probes allow for flexible choice of imaging equipment when performing quenched-phosphorescence O2 measurements: one- or two-photon, PLIM or intensity-based ratiometric read-outs. Spectral and temporal (e.g. FLIMPLIM) discrimination can be used to image O2 together with pH, Ca2+, mitochondrial membrane potential, cell death markers or cell/organelle specific markers. However, the main challenge of existing nanoparticle probes is their limited diffusion across thick (> 20-50 μm) 3D cell models such as tumor spheroids. Here, we present new class of polymeric nanoparticle probes having tunable size, charge, cell-penetrating ability, and reporter dyes. Being spectrally similar to the recently described MM2, PA2 and other O2 probes, they are 5-10 times brighter, demonstrate improved ratiometric response and their surface chemistry can be easily modified. With cultures of 2D and 3D cell models (fibroblasts, PC12 aggregates, HCT116 human colon cancer spheroids) we found cell-specific staining by these probes. However, the efficient staining of model of interest can be tuned by changing number of positive and negative surface groups at nanoparticle, to allow most efficient loading. We also demonstrate how real-time monitoring of oxygenation can be used to select optimal spheroid production with low variability in size and high cell viability.

  7. Two new ad-hoc models of detection physics and their evaluation for navigated beta probe surface imaging

    NASA Astrophysics Data System (ADS)

    Shakir, Dzhoshkun I.; Hartl, Alexander; Schneider, Florian R.; Pulko, Jozef; Ziegler, Sibylle I.; Navab, Nassir; Lasser, Tobias

    2012-02-01

    Intra-operative surface imaging with navigated beta probes in conjunction with positron-emitting radiotracers like 18F-FDG has been shown to enable control of tumor resection borders. We showed previously that employing iterative reconstruction (MLEM) in conjunction with an ad-hoc model of the detection physics (based on solid-angle geometry, SA) improves the image quality. In this study, we sampled the beta probe readings of a point source using a precision step-motor to generate a look-up-table (LUT) model. We also generated a simplified geometrical model (SG) based on this data set. To see how these two models influence the image quality compared to the old SA model, we reconstructed images from sparsely sampled datasets of a phantom with three hotspots using each model. The images yielded 76% (SA), 81% (SG), and 81% (LUT) mean NCC compared to the ground truth. The SG and LUT models, however, could resolve the hotspots better in the datasets where the detector-to-phantom distance was larger. Additionally, we compared the deviations of the SA and SG analytical models to the measured LUT model, where we found that the SG model gives estimates substantially closer to the actual beta probe readings than the previous SA model.

  8. Ex-vivo endoscopic laryngeal cancer imaging using two forward-looking fiber optic scanning endoscope probes

    NASA Astrophysics Data System (ADS)

    Cernat, R.; Tatla, T.; Pang, J.-Y.; Tadrous, P. J.; Gelikonov, G.; Gelikonov, V.; Zhang, Y. Y.; Bradu, A.; Li, X. D.; Podoleanu, A. G.

    2012-12-01

    Larynx cancer is one of the most common primary head and neck cancers. For early-stage laryngeal cancer, both surgery and radiotherapy are effective treatment modalities, offering a high rate of local control and cure. Optical coherence tomography (OCT) is an established non-invasive optical biopsy method, capable of imaging ranges of 2- 3 mm into tissue. By using the principles of low coherence light interferometry, OCT can be used to distinguish normal from unhealthy laryngeal mucosa in patients. Two forward-looking endoscope OCT probes of different sizes in a sweeping frequency OCT (SS-OCT) configuration were compared in terms of their performances for ex-vivo laryngeal cancer imaging. The setup configuration of the first OCT probe unit was designed and constructed at the Institute of Applied Physics RAS, Russia (diameter of 1.9 mm and the rigid part at the distal end is 13 mm long). The second OCT endoscope probe was constructed at the Department of Biomedical Engineering at Johns Hopkins University, USA, using a tubular piezoelectric actuator with quartered electrodes in combination with a resonant fiber cantilever (diameter of 2.4 mm, and rigid part of 45 mm). Cross-sectional images of laryngeal lesions using the two OCT configurations were aquired and compared with OCT images obtained in a 1310 nm SS-OCT classical non-endoscopic system. The work presented here is an intermediate step in our research towards in-vivo endoscopic laryngeal cancer imaging.

  9. Quantitative imaging of electrospun fibers by PeakForce Quantitative NanoMechanics atomic force microscopy using etched scanning probes.

    PubMed

    Chlanda, Adrian; Rebis, Janusz; Kijeńska, Ewa; Wozniak, Michal J; Rozniatowski, Krzysztof; Swieszkowski, Wojciech; Kurzydlowski, Krzysztof J

    2015-05-01

    Electrospun polymeric submicron and nanofibers can be used as tissue engineering scaffolds in regenerative medicine. In physiological conditions fibers are subjected to stresses and strains from the surrounding biological environment. Such stresses can cause permanent deformation or even failure to their structure. Therefore, there is a growing necessity to characterize their mechanical properties, especially at the nanoscale. Atomic force microscopy is a powerful tool for the visualization and probing of selected mechanical properties of materials in biomedical sciences. Image resolution of atomic force microscopy techniques depends on the equipment quality and shape of the scanning probe. The probe radius and aspect ratio has huge impact on the quality of measurement. In the presented work the nanomechanical properties of four different polymer based electrospun fibers were tested using PeakForce Quantitative NanoMechanics atomic force microscopy, with standard and modified scanning probes. Standard, commercially available probes have been modified by etching using focused ion beam (FIB). Results have shown that modified probes can be used for mechanical properties mapping of biomaterial in the nanoscale, and generate nanomechanical information where conventional tips fail.

  10. Erythrocyte-derived nano-probes functionalized with antibodies for targeted near infrared fluorescence imaging of cancer cells

    PubMed Central

    Mac, Jenny T.; Nuñez, Vicente; Burns, Joshua M.; Guerrero, Yadir A.; Vullev, Valentine I.; Anvari, Bahman

    2016-01-01

    Constructs derived from mammalian cells are emerging as a new generation of nano-scale platforms for clinical imaging applications. Herein, we report successful engineering of hybrid nano-structures composed of erythrocyte-derived membranes doped with FDA-approved near infrared (NIR) chromophore, indocyanine green (ICG), and surface-functionalized with antibodies to achieve molecular targeting. We demonstrate that these constructs can be used for targeted imaging of cancer cells in vitro. These erythrocyte-derived optical nano-probes may provide a potential platform for clinical translation, and enable molecular imaging of cancer biomarkers. PMID:27446657

  11. Thrombin-mediated ratiometric two-photon fluorescent probe for selective imaging of endogenous ultratrace glutathione in platelet.

    PubMed

    Zhang, Hua; Wang, Caixia; Wang, Ge; Wang, Kui; Jiang, Kai

    2016-04-15

    Ultratrace change of reduced glutathione (GSH) can weaken coagulation function of platelet (PLT). Thus, rapid and sensitive imaging of GSH specific in PLT is beneficial for monitoring coagulation function of PLT. Many fluorescent probes for GSH have been reported, but ratio fluorescent probe with excellent two-photon property for screening PLT from peripheral blood and quantitative imaging of GSH are scarce. In this work, a thrombin-mediated two-photon GSH-specific fluorescent probe (IQDC-L) was reported. Sulfuric diamide, a key group as linker, was introduced into IQDC-L, which resulted in not only specific selectivity for GSH, but also FRET occurring in probe. When IQDC-L encountered GSH, "S-N" in sulfonamide group was cut off, and FRET was inhibited. Furthermore, fluorescence intensities at 520 and 595 nm presented linear change on ratio mode in the range of GSH (2.0-65 nM). The lowest detection for GSH was as low as 0.083 nM. Intriguingly, IQDC-L under thrombin-mediated was able to screen PLT from peripheral blood without any interference. Thus, IQDC-L could be used to screen PLT from peripheral blood, and simultaneously, to in situ image ultratrace GSH. PMID:26649492

  12. Thrombin-mediated ratiometric two-photon fluorescent probe for selective imaging of endogenous ultratrace glutathione in platelet.

    PubMed

    Zhang, Hua; Wang, Caixia; Wang, Ge; Wang, Kui; Jiang, Kai

    2016-04-15

    Ultratrace change of reduced glutathione (GSH) can weaken coagulation function of platelet (PLT). Thus, rapid and sensitive imaging of GSH specific in PLT is beneficial for monitoring coagulation function of PLT. Many fluorescent probes for GSH have been reported, but ratio fluorescent probe with excellent two-photon property for screening PLT from peripheral blood and quantitative imaging of GSH are scarce. In this work, a thrombin-mediated two-photon GSH-specific fluorescent probe (IQDC-L) was reported. Sulfuric diamide, a key group as linker, was introduced into IQDC-L, which resulted in not only specific selectivity for GSH, but also FRET occurring in probe. When IQDC-L encountered GSH, "S-N" in sulfonamide group was cut off, and FRET was inhibited. Furthermore, fluorescence intensities at 520 and 595 nm presented linear change on ratio mode in the range of GSH (2.0-65 nM). The lowest detection for GSH was as low as 0.083 nM. Intriguingly, IQDC-L under thrombin-mediated was able to screen PLT from peripheral blood without any interference. Thus, IQDC-L could be used to screen PLT from peripheral blood, and simultaneously, to in situ image ultratrace GSH.

  13. In Vivo Optical Imaging of Acute Cell Death Using a Near-Infrared Fluorescent Zinc-Dipicolylamine Probe

    PubMed Central

    Smith, Bryan A.; Gammon, Seth T.; Xiao, Shuzhang; Wang, Wei; Chapman, Sarah; McDermott, Ryan; Suckow, Mark A.; Johnson, James R.; Piwnica-Worms, David; Gokel, George W.; Smith, Bradley D.; Leevy, W. Matthew

    2013-01-01

    Cell death is a fundamental biological process that is present in numerous disease pathologies. Fluorescent probes that detect cell death have been developed for a myriad of research applications ranging from microscopy to in vivo imaging. Here we describe a synthetic near infrared conjugate of zinc(II)-dipicolylamine (Zn2+-DPA) for in vivo imaging of cell death. Chemically induced in vivo models of myopathy were established using an ionphore, ethanol, or ketamine as chemical cytotoxins. The Zn2+-DPA fluorescent probe or corresponding control was subsequently injected and whole animal fluorescence imaging demonstrated probe uptake at the site of muscle damage, which was confirmed by ex vivo and histological analyses. Further, a comparative study with a near-infrared fluorescent conjugate Annexin V showed less intense uptake at the site of muscle damage and high accumulation in the bladder. The results indicate that the fluorescent Zn2+-DPA conjugate is an effective probe for in vivo cell death detection and in some cases may be an appropriate alternative to fluorescent Annexin V conjugates. PMID:21323375

  14. In vivo optical imaging of acute cell death using a near-infrared fluorescent zinc-dipicolylamine probe.

    PubMed

    Smith, Bryan A; Gammon, Seth T; Xiao, Shuzhang; Wang, Wei; Chapman, Sarah; McDermott, Ryan; Suckow, Mark A; Johnson, James R; Piwnica-Worms, David; Gokel, George W; Smith, Bradley D; Leevy, W Matthew

    2011-04-01

    Cell death is a fundamental biological process that is present in numerous disease pathologies. Fluorescent probes that detect cell death have been developed for a myriad of research applications ranging from microscopy to in vivo imaging. Here we describe a synthetic near-infrared (NIR) conjugate of zinc(II)-dipicolylamine (Zn²+-DPA) for in vivo imaging of cell death. Chemically induced in vivo models of myopathy were established using an ionphore, ethanol, or ketamine as cytotoxins. The Zn²+-DPA fluorescent probe or corresponding control was subsequently injected, and whole animal fluorescence imaging demonstrated probe uptake at the site of muscle damage, which was confirmed by ex vivo and histological analyses. Further, a comparative study with a NIR fluorescent conjugate Annexin V showed less intense uptake at the site of muscle damage and high accumulation in the bladder. The results indicate that the fluorescent Zn²+-DPA conjugate is an effective probe for in vivo cell death detection and in some cases may be an appropriate alternative to fluorescent Annexin V conjugates.

  15. A near-infrared genetically targetable and activatable photosensitizer

    PubMed Central

    He, Jianjun; Wang, Yi; Missinato, Maria A.; Onuoha, Ezenwa; Perkins, Lydia A.; Watkins, Simon C.; St. Croix, Claudette M.; Tsang, Michael; Bruchez, Marcel P.

    2016-01-01

    Upon illumination, photosensitizer molecules produce reactive oxygen species (ROS) that can be utilized for functional manipulation of living cells, including protein inactivation, targeted damage introduction, and cellular ablation. Photosensitizers used to date have been either exogenous, resulting in delivery and removal challenges, or genetically encoded proteins that form or bind a native photosensitizing molecule, resulting in a constitutively active photosensitizer inside the cell. By binding a heavy-atom substituted fluorogenic dye with a genetically encoded Fluorogen Activating Protein (FAP), we demonstrate an ‘on-demand’ activated photosensitizer that produces singlet oxygen and fluorescence only when FAP-bound and activated with near infrared light. This Targeted and Activated Photosensitizer (TAPs) approach enables protein inactivation and targeted cell killing in cultured cells and rapid targeted lineage ablation in living larval and adult zebrafish. The near-infrared excitation and emission of this FAP-TAPs photosensitizer module provides a new spectral range for photosensitizer proteins, useful for imaging, manipulation and cellular ablation deep within living organisms. PMID:26808669

  16. Cyanine-based probe\\tag-peptide pair for fluorescence protein imaging and fluorescence protein imaging methods

    DOEpatents

    Mayer-Cumblidge, M. Uljana; Cao, Haishi

    2010-08-17

    A molecular probe comprises two arsenic atoms and at least one cyanine based moiety. A method of producing a molecular probe includes providing a molecule having a first formula, treating the molecule with HgOAc, and subsequently transmetallizing with AsCl.sub.3. The As is liganded to ethanedithiol to produce a probe having a second formula. A method of labeling a peptide includes providing a peptide comprising a tag sequence and contacting the peptide with a biarsenical molecular probe. A complex is formed comprising the tag sequence and the molecular probe. A method of studying a peptide includes providing a mixture containing a peptide comprising a peptide tag sequence, adding a biarsenical probe to the mixture, and monitoring the fluorescence of the mixture.

  17. Selective imaging of quorum sensing receptors in bacteria using fluorescent Au nanocluster probes surface functionalized with signal molecules.

    PubMed

    Mukherji, Ruchira; Samanta, Anupam; Illathvalappil, Rajith; Chowdhury, Somak; Prabhune, Asmita; Devi, R Nandini

    2013-12-26

    Fluorescent ultrasmall gold clusters decorated with bacterial quorum sensing signal molecules, acyl homoserine lactone, are synthesized. These fluorescent probes are found to have emission in the near-infrared spectral region advantageous for bioimaging. Imaging studies using different strains of bacteria with and without acyl homoserine lactone receptors with the aid of confocal microscopy have shown that the probe interacts preferentially with cells possessing these receptors. This indicates that, with appropriate surface functionalization, the Au clusters can be used for receptor specific detection with enhanced selectivity.

  18. Correcting nonlinear drift distortion of scanning probe and scanning transmission electron microscopies from image pairs with orthogonal scan directions.

    PubMed

    Ophus, Colin; Ciston, Jim; Nelson, Chris T

    2016-03-01

    Unwanted motion of the probe with respect to the sample is a ubiquitous problem in scanning probe and scanning transmission electron microscopies, causing both linear and nonlinear artifacts in experimental images. We have designed a procedure to correct these artifacts by using orthogonal scan pairs to align each measurement line-by-line along the slow scan direction, by fitting contrast variation along the lines. We demonstrate the accuracy of our algorithm on both synthetic and experimental data and provide an implementation of our method.

  19. Bright and photostable fluorescent probe with aggregation-induced emission characteristics for specific lysosome imaging and tracking.

    PubMed

    Ouyang, Jiang; Zang, Qiguang; Chen, Wansong; Wang, Liqiang; Li, Shuo; Liu, Ren-Yu; Deng, Yuanyuan; Liu, Zhao-Qian; Li, Juan; Deng, Liu; Liu, You-Nian

    2016-10-01

    We develop a new lysosome-targeting AIE fluorescent probe tetraphenylethene-morpholine (TPE-MPL), by incorporating a typical lysosome-targeting moiety of morpholine into a stable tetraphenylethene skeleton. Due to both the AIE and antenna effects, TPE-MPL possesses superior photostability, appreciable tolerance to microenvironment change and high lysosome targeting ability. Our findings confirm that TPE-MPL is a well-suited imaging agent for targeting lysosome and tracking dynamic movement of lysosome. Moreover, due to its synthetic accessibility, TPE-MPL could be further modified as a dual-functional probe for lysosome, thereby gain further insight into the role of lysosome in biomedical applications. PMID:27474306

  20. Dual-factor triggered fluorogenic nanoprobe for ultrahigh contrast and subdiffraction fluorescence imaging

    PubMed Central

    Wang, Zhe; Zhang, Xiaoxiang; Huang, Peng; Zhao, Weidong; Liu, Dingbin; Nie, Liming; Yue, Xuyi; Wang, Shouju; Ma, Ying; Kiesewetter, Dale; Niu, Gang; Chen, Xiaoyuan

    2014-01-01

    Ultrahigh contrast fluorescence molecular imaging has long been pursued over the past few decades from basic sciences to clinics. Although new classes of near-infrared (NIR) molecular probes are emerging, the requirement of fluorophores with high quantum yield, high signal to noise (S/N) ratio, and being activatable to microenvironment changes can hardly be fulfilled. In this study, a new NIR dye embedded fluorogenic nanoprobe (fg-nanoprobe) was developed for ultrahigh contrast in vitro and in vivo imaging with negligible background interference. The achieved S/N ratio was found to be attributed to the synergistic effects of the cellular compartmental triggered fluorogenicity and pH tunable fluorescence on/off character. In addition, this constructed fluorogenic nanoprobe could be coupled with image processing method for super-resolution subdiffraction imaging. The developed fg-nanoprobe integrated photophysical merits of the synthesized NIR fluorophore and advantages of engineered nanoparticle for enhanced fluorescence molecular imaging. This probe may open another avenue for ultrahigh contrast fluorescence molecular imaging in the future. PMID:23721793

  1. Dual-factor triggered fluorogenic nanoprobe for ultrahigh contrast and subdiffraction fluorescence imaging.

    PubMed

    Wang, Zhe; Zhang, Xiaoxiang; Huang, Peng; Zhao, Weidong; Liu, Dingbin; Nie, Liming; Yue, Xuyi; Wang, Shouju; Ma, Ying; Kiesewetter, Dale; Niu, Gang; Chen, Xiaoyuan

    2013-08-01

    Ultrahigh contrast fluorescence molecular imaging has long been pursued over the past few decades from basic sciences to clinics. Although new classes of near-infrared (NIR) molecular probes are emerging, the requirement of fluorophores with high quantum yield, high signal to noise (S/N) ratio, and being activatable to microenvironment changes can hardly be fulfilled. In this study, a new NIR dye embedded fluorogenic nanoprobe (fg-nanoprobe) was developed for ultrahigh contrast in vitro and in vivo imaging with negligible background interference. The achieved S/N ratio was found to be attributed to the synergistic effects of the cellular compartmental triggered fluorogenicity and pH tunable fluorescence on/off character. In addition, this constructed fluorogenic nanoprobe could be coupled with image processing method for super-resolution subdiffraction imaging. The developed fg-nanoprobe integrated photophysical merits of the synthesized NIR fluorophore and advantages of engineered nanoparticle for enhanced fluorescence molecular imaging. This probe may open another avenue for ultrahigh contrast fluorescence molecular imaging in the future.

  2. VLBI imaging and astrometry of the Gravity Probe B guide star HR 8703

    NASA Astrophysics Data System (ADS)

    Ransom, Ryan R.

    Gravity Probe B (GP-B) is the spaceborne relativity experiment developed by NASA and Stanford University to test two predictions of general relativity (GR). The experiment will use four super-conducting gyroscopes, contained in a low-earth, polar orbiting spacecraft, to precisely measure the geodetic effect and the much smaller frame-dragging effect. According to GR, each of the effects will induce precessions in the gyroscopes. For the frame-dragging effect, the predicted precession is ˜42 mas/yr (mas ≡ milliarcsecond). The precessions will be measured with respect to a "guide star," namely the RS CVn binary star HR 8703 (IM Pegasi). The goal of the GP-B experiment is to measure the precessions with a standard error of about 0.5 mas/yr or better. To achieve this level of precision, the proper motion of the guide star must be determined in an inertial reference frame with a standard error ≤0.15 mas/yr. Nineteen sets of very-long-baseline interferometry (VLBI) observations at 8.4 GHz between January 1997 and June 2001 were made of HR 8703 and two extragalactic reference sources, 3C454.3 and B2250+194, in support of GP-B. We produced VLBI images of 3C454.3 and B2250+194 for each observing session, and VLBI images of HR 8703 for all but one of the observing sessions. The images of HR 8703 show a variety of radio source structures which range from compact single-emission-region structures <1 mas in angular diameter to complex double-lobe structures with lobe separations of ˜1.5 mas. Moreover, images from temporal subsets of several observing sessions show on hour time scales both structural evolution in the emission source and motions of the radio centroid of up to ˜1 mas. This is the first time that hourly activity on or close to a star has been observed directly, apart from the activity on the Sun. Based upon an astrometric analysis of the phase-referenced positions obtained at each epoch, we have (1) made precise determinations of HR 8703's parallax and

  3. A quantum dot probe conjugated with aβ antibody for molecular imaging of Alzheimer's disease in a mouse model.

    PubMed

    Feng, Li; Long, Hong-Yu; Liu, Ren-Kai; Sun, Dan-Ni; Liu, Chao; Long, Li-Li; Li, Yi; Chen, Si; Xiao, Bo

    2013-08-01

    The treatment of Alzheimer's disease (AD) has been hampered by a lack of sensitive and specific non-invasive diagnostic methods. Quantum dots (QD) are nano-crystals with unique photo-physical properties that bypass some of the limitations of conventional dyes and imaging tools. This study is aimed to evaluate the fluorescence properties of a QD probe conjugated with an anti-Aβ antibody (QD-Aβ-Ab). Healthy mice and mice bearing mutated human APP695swe and APP717 V-F transgenes received intracerebroventricular injection of the probe for subsequent imaging. Immunohistochemistry revealed that Aβ1-42 was distributed in the hippocampus CA1 area in the APP transgenic mice. Fluorescence microscopy demonstrated that fluorescence was mainly observed in the hippocampus area, the cerebral cortex, sagittal septum and striatum of APP transgenic mice. In vivo imaging of mice receiving the QD-Aβ-Ab probe showed that healthy mice exhibited a narrow range of fluorescence and lower fluorescence intensity compared with APP transgenic mice. The mean fluorescence intensity of brain tissues of healthy C57BL mice was 12.3784 ± 3.9826, which was significantly lower than that of 10- and 16-month-old APP transgenic mice (45.03 ± 2.66 and 46.69 ± 3.22, respectively; P < 0.05). In this study we present the first direct evidence that QD-Aβ-Ab conjugate probes can track in vivo state of Aβ accumulation in mice and the findings suggest that such probes may be of potential use for early molecular diagnostic imaging of AD.

  4. A Molecular Imaging Approach to Mercury Sensing Based on Hyperpolarized (129)Xe Molecular Clamp Probe.

    PubMed

    Guo, Qianni; Zeng, Qingbin; Jiang, Weiping; Zhang, Xiaoxiao; Luo, Qing; Zhang, Xu; Bouchard, Louis-S; Liu, Maili; Zhou, Xin

    2016-03-14

    Mercury pollution, in the form of mercury ions (Hg(2+)), is a major health and environmental hazard. Commonly used sensors are invasive and limited to point measurements. Fluorescence-based sensors do not provide depth resolution needed to image spatial distributions. Herein we report a novel sensor capable of yielding spatial distributions by MRI using hyperpolarized (129)Xe. A molecular clamp probe was developed consisting of dipyrrolylquinoxaline (DPQ) derivatives and twocryptophane-A cages. The DPQ derivatives act as cation receptors whereas cryptophane-A acts as a suitable host molecule for xenon. When the DPQ moiety interacts with mercury ions, the molecular clamp closes on the ion. Due to overlap of the electron clouds of the two cryptophane-A cages, the shielding effect on the encapsulated Xe becomes important. This leads to an upfield change of the chemical shift of the encapsulated Xe. This sensor exhibits good selectivity and sensitivity toward the mercury ion. This mercury-activated hyperpolarized (129)Xe-based chemosensor is a new concept method for monitoring Hg(2+) ion distributions by MRI.

  5. DNA-templated Ag nanoclusters as fluorescent probes for sensing and intracellular imaging of hydroxyl radicals.

    PubMed

    Zhang, Li; Liang, Ru-Ping; Xiao, Sai-Jin; Bai, Jian-Mei; Zheng, Lin-Ling; Zhan, Lei; Zhao, Xi-Juan; Qiu, Jian-Ding; Huang, Cheng-Zhi

    2014-01-01

    We have developed a simple, rapid and label-free sensor for the essential biological OH radicals based on the fluorescence quenching of DNA-templated Ag nanoclusters (DNA-Ag NCs). The OH radicals generated from the Fenton reagent attack and cleave the DNA template, which disturbs the microenvironments around Ag NCs, resulting in spontaneous aggregation due to the lack of stabilization and further the quenching of the Ag NCs fluorescence. These changes in fluorescence intensity allow sensing of OH radicals with good sensitivity and selectivity under optimal conditions. The sensor can be also applied for quantifying the radical scavenging action of antioxidants. Various characterizations including absorption spectra, fluorescence lifetimes, light scattering (LS) spectra, transmission electron microscopy (TEM), dark field light scattering imaging, and circular dichroism (CD) spectrometry have been employed to illustrate the proposed sensing mechanism. Further investigations demonstrate that the fluorescent probe could penetrate into intact cell membranes to selectively detect intracellular OH radicals induced by the phorbol myristate acetate (PMA) stimulation. These advantageous characteristics make the fluorescent DNA-Ag NCs potentially useful as a new candidate to monitor OH in broad biosystems. PMID:24274306

  6. Scanning Hall Probe Microscope and Imaging of Vortex Penetration into Nb

    NASA Astrophysics Data System (ADS)

    Bove, A.; Kundtz, N.; Chang, A. M.; Gusiatnikov, V.; Lichtenberger, Art

    2006-03-01

    We report on the construction of a scanning Hall probe microscope with 100 nm lateral resolution and a large scan range, which exceeds 40 μm at 4.2 K. The microscope is based on the beetle design and operates between room temperature and 1.5 K. The DSP-based control electronics achieves a high (100 kHz) sampling rate and a low noise. The system is capable of simultaneous tunneling and Hall signal acquisition. The Hall sensor for measuring local magnetic fields is fabricated on a GaAs heterostructure through standard EBL and wet etching. It has an active area of 300 nm x 300 nm and a sensistivity of 0.2 φ/Gauss. We will present (1) a description of the microscope, and (2) progress on imaging the penetration of vortices and the growth of vortex dendritic patterns into thin Nb films. Altshuler E. et al., Rev. Mod. Phys.76, 471 (April 2004) Hallen H. D. et al., Solid State Commumications 99 (9), 651-654 (SEP 1996).

  7. Imaging thermal conductivity with nanoscale resolution using a scanning spin probe

    DOE PAGES

    Laraoui, Abdelghani; Aycock-Rizzo, Halley; Gao, Yang; Lu, Xi; Riedo, Elisa; Meriles, Carlos A.

    2015-11-20

    The ability to probe nanoscale heat flow in a material is often limited by lack of spatial resolution. Here, we use a diamond-nanocrystal-hosted nitrogen-vacancy centre attached to the apex of a silicon thermal tip as a local temperature sensor. We apply an electrical current to heat up the tip and rely on the nitrogen vacancy to monitor the thermal changes the tip experiences as it is brought into contact with surfaces of varying thermal conductivity. By combining atomic force and confocal microscopy, we image phantom microstructures with nanoscale resolution, and attain excellent agreement between the thermal conductivity and topographic maps.more » The small mass and high thermal conductivity of the diamond host make the time response of our technique short, which we demonstrate by monitoring the tip temperature upon application of a heat pulse. Our approach promises multiple applications, from the investigation of phonon dynamics in nanostructures to the characterization of heterogeneous phase transitions and chemical reactions in various solid-state systems.« less

  8. Imaging thermal conductivity with nanoscale resolution using a scanning spin probe

    SciTech Connect

    Laraoui, Abdelghani; Aycock-Rizzo, Halley; Gao, Yang; Lu, Xi; Riedo, Elisa; Meriles, Carlos A.

    2015-11-20

    The ability to probe nanoscale heat flow in a material is often limited by lack of spatial resolution. Here, we use a diamond-nanocrystal-hosted nitrogen-vacancy centre attached to the apex of a silicon thermal tip as a local temperature sensor. We apply an electrical current to heat up the tip and rely on the nitrogen vacancy to monitor the thermal changes the tip experiences as it is brought into contact with surfaces of varying thermal conductivity. By combining atomic force and confocal microscopy, we image phantom microstructures with nanoscale resolution, and attain excellent agreement between the thermal conductivity and topographic maps. The small mass and high thermal conductivity of the diamond host make the time response of our technique short, which we demonstrate by monitoring the tip temperature upon application of a heat pulse. Our approach promises multiple applications, from the investigation of phonon dynamics in nanostructures to the characterization of heterogeneous phase transitions and chemical reactions in various solid-state systems.

  9. Imaging thermal conductivity with nanoscale resolution using a scanning spin probe

    PubMed Central

    Laraoui, Abdelghani; Aycock-Rizzo, Halley; Gao, Yang; Lu, Xi; Riedo, Elisa; Meriles, Carlos A.

    2015-01-01

    The ability to probe nanoscale heat flow in a material is often limited by lack of spatial resolution. Here, we use a diamond-nanocrystal-hosted nitrogen-vacancy centre attached to the apex of a silicon thermal tip as a local temperature sensor. We apply an electrical current to heat up the tip and rely on the nitrogen vacancy to monitor the thermal change