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Sample records for cetuximab-based imaging probe

  1. [A Case of Pneumocystis Pneumonia after Cetuximab-based Bioradiotherapy].

    PubMed

    Shinohara, Asano; Kogo, Ryunosuke; Uryu, Hideoki; Yasumatsu, Ryuji; Nakashima, Torahiko; Komune, Shizuo

    2016-03-01

    Reports of drug-induced interstitial pneumonia caused by Cetuximab have been increasing. Pneumocystis pneumonia is important as a differential diagnosis of drug-induced interstitial pneumonia. We report herein on a 64-year-old man with pneumocystis pneumonia after cetuximab-based bioradiotherapy for laryngeal cancer. After radiotherapy, the patient developed multi-drug resistant pneumonia. Chest CT imaging revealed diffuse ground-glass opacities in the lung field. He was diagnosed as having pneumocystis pneumonia based on the bronchoalveolar lavage (BAL) findings, and then his symptoms improved after treatment with Trimethoprim/Sulfamethoxazole. It is important to assess the risk factor for pneumocystis pneumonia for early its detection and treatment.

  2. Multispectral imaging probe

    SciTech Connect

    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.

  3. 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.

  4. Optical imaging probes in oncology

    PubMed Central

    Martelli, Cristina; Dico, Alessia Lo; Diceglie, Cecilia; Lucignani, Giovanni; Ottobrini, Luisa

    2016-01-01

    Cancer is a complex disease, characterized by alteration of different physiological molecular processes and cellular features. Keeping this in mind, the possibility of early identification and detection of specific tumor biomarkers by non-invasive approaches could improve early diagnosis and patient management. Different molecular imaging procedures provide powerful tools for detection and non-invasive characterization of oncological lesions. Clinical studies are mainly based on the use of computed tomography, nuclear-based imaging techniques and magnetic resonance imaging. Preclinical imaging in small animal models entails the use of dedicated instruments, and beyond the already cited imaging techniques, it includes also optical imaging studies. Optical imaging strategies are based on the use of luminescent or fluorescent reporter genes or injectable fluorescent or luminescent probes that provide the possibility to study tumor features even by means of fluorescence and luminescence imaging. Currently, most of these probes are used only in animal models, but the possibility of applying some of them also in the clinics is under evaluation. The importance of tumor imaging, the ease of use of optical imaging instruments, the commercial availability of a wide range of probes as well as the continuous description of newly developed probes, demonstrate the significance of these applications. The aim of this review is providing a complete description of the possible optical imaging procedures available for the non-invasive assessment of tumor features in oncological murine models. In particular, the characteristics of both commercially available and newly developed probes will be outlined and discussed. PMID:27145373

  5. Optical imaging probes in oncology.

    PubMed

    Martelli, Cristina; Lo Dico, Alessia; Diceglie, Cecilia; Lucignani, Giovanni; Ottobrini, Luisa

    2016-07-26

    Cancer is a complex disease, characterized by alteration of different physiological molecular processes and cellular features. Keeping this in mind, the possibility of early identification and detection of specific tumor biomarkers by non-invasive approaches could improve early diagnosis and patient management.Different molecular imaging procedures provide powerful tools for detection and non-invasive characterization of oncological lesions. Clinical studies are mainly based on the use of computed tomography, nuclear-based imaging techniques and magnetic resonance imaging. Preclinical imaging in small animal models entails the use of dedicated instruments, and beyond the already cited imaging techniques, it includes also optical imaging studies. Optical imaging strategies are based on the use of luminescent or fluorescent reporter genes or injectable fluorescent or luminescent probes that provide the possibility to study tumor features even by means of fluorescence and luminescence imaging. Currently, most of these probes are used only in animal models, but the possibility of applying some of them also in the clinics is under evaluation.The importance of tumor imaging, the ease of use of optical imaging instruments, the commercial availability of a wide range of probes as well as the continuous description of newly developed probes, demonstrate the significance of these applications. The aim of this review is providing a complete description of the possible optical imaging procedures available for the non-invasive assessment of tumor features in oncological murine models. In particular, the characteristics of both commercially available and newly developed probes will be outlined and discussed.

  6. 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.

  7. Gamma-Ray Imaging Probes.

    NASA Astrophysics Data System (ADS)

    Wild, Walter James

    1988-12-01

    External nuclear medicine diagnostic imaging of early primary and metastatic lung cancer tumors is difficult due to the poor sensitivity and resolution of existing gamma cameras. Nonimaging counting detectors used for internal tumor detection give ambiguous results because distant background variations are difficult to discriminate from neighboring tumor sites. This suggests that an internal imaging nuclear medicine probe, particularly an esophageal probe, may be advantageously used to detect small tumors because of the ability to discriminate against background variations and the capability to get close to sites neighboring the esophagus. The design, theory of operation, preliminary bench tests, characterization of noise behavior and optimization of such an imaging probe is the central theme of this work. The central concept lies in the representation of the aperture shell by a sequence of binary digits. This, coupled with the mode of operation which is data encoding within an axial slice of space, leads to the fundamental imaging equation in which the coding operation is conveniently described by a circulant matrix operator. The coding/decoding process is a classic coded-aperture problem, and various estimators to achieve decoding are discussed. Some estimators require a priori information about the object (or object class) being imaged; the only unbiased estimator that does not impose this requirement is the simple inverse-matrix operator. The effects of noise on the estimate (or reconstruction) is discussed for general noise models and various codes/decoding operators. The choice of an optimal aperture for detector count times of clinical relevance is examined using a statistical class-separability formalism.

  8. 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

  9. 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.

  10. 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

  11. Techniques for molecular imaging probe design.

    PubMed

    Reynolds, Fred; Kelly, Kimberly A

    2011-12-01

    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 discuss target selection, screening techniques, and probe optimization with the aim of developing clinically relevant molecularly targeted imaging agents.

  12. 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

  13. Pathological response after neoadjuvant bevacizumab- or cetuximab-based chemotherapy in resected colorectal cancer liver metastases.

    PubMed

    Pietrantonio, Filippo; Mazzaferro, Vincenzo; Miceli, Rosalba; Cotsoglou, Christian; Melotti, Flavia; Fanetti, Giuseppe; Perrone, Federica; Biondani, Pamela; Muscarà, Cecilia; Di Bartolomeo, Maria; Coppa, Jorgelina; Maggi, Claudia; Milione, Massimo; Tamborini, Elena; de Braud, Filippo

    2015-07-01

    Neoadjuvant chemotherapy (NACT) prior to liver resection is advantageous for patients with colorectal cancer liver metastases (CLM). Bevacizumab- or cetuximab-based NACT may affect patient outcome and curative resection rate, but comparative studies on differential tumour regression grade (TRG) associated with distinct antibodies-associated regimens are lacking. Ninety-three consecutive patients received NACT plus bevacizumab (n = 46) or cetuximab (n = 47) followed by CLM resection. Pathological response was determined in each resected metastasis as TRG rated from 1 (complete) to 5 (no response). Except for KRAS mutations prevailing in bevacizumab versus cetuximab (57 vs. 21 %, p = 0.001), patients characteristics were well balanced. Median follow-up was 31 months (IQR 17-48). Bevacizumab induced significantly better pathological response rates (TRG1-3: 78 vs. 34 %, p < 0.001) as well as complete responses (TRG1: 13 vs. 0 %, p = 0.012) with respect to cetuximab. Three-year progression-free survival (PFS) and overall survival (OS) were not significantly different in the two cohorts. At multivariable analysis, significant association with pathological response was found for number of resected metastases (p = 0.015) and bevacizumab allocation (p < 0.001), while KRAS mutation showed only a trend. Significant association with poorer PFS and OS was found for low grades of pathological response (p = 0.009 and p < 0.001, respectively), R2 resection or presence of extrahepatic disease (both p < 0.001) and presence of KRAS mutation (p = 0.007 and p < 0.001, respectively). Bevacizumab-based regimens, although influenced by the number of metastases and KRAS status, improve significantly pathological response if compared to cetuximab-based NACT. Possible differential impact among regimens on patient outcome has still to be elucidated.

  14. 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.

  15. 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

  16. 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.

  17. 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

  18. Image processing for HTS SQUID probe microscope

    NASA Astrophysics Data System (ADS)

    Hayashi, T.; Koetitz, R.; Itozaki, H.; Ishikawa, T.; Kawabe, U.

    2005-10-01

    An HTS SQUID probe microscope has been developed using a high-permeability needle to enable high spatial resolution measurement of samples in air even at room temperature. Image processing techniques have also been developed to improve the magnetic field images obtained from the microscope. Artifacts in the data occur due to electromagnetic interference from electric power lines, line drift and flux trapping. The electromagnetic interference could successfully be removed by eliminating the noise peaks from the power spectrum of fast Fourier transforms of line scans of the image. The drift between lines was removed by interpolating the mean field value of each scan line. Artifacts in line scans occurring due to flux trapping or unexpected noise were removed by the detection of a sharp drift and interpolation using the line data of neighboring lines. Highly detailed magnetic field images were obtained from the HTS SQUID probe microscope by the application of these image processing techniques.

  19. 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.

  20. Targeted Probes for Cardiovascular MR Imaging

    PubMed Central

    Uppal, Ritika; Caravan, Peter

    2010-01-01

    Background Molecular magnetic resonance (MR) imaging plays an important role in studying molecular and cellular processes associated with heart disease. Targeted probes that recognize important biomarkers of atherosclerosis, apoptosis, necrosis, angiogenesis, thrombosis and inflammation have been developed. Discussion This review discusses properties of chemically different types of contrast agents including iron oxide nanoparticles, gadolinium based nanoparticles or micelles, discrete peptide conjugates and activatable probes. Numerous examples of contrast agents based on these approaches have been used in preclinical MR imaging of cardiovascular diseases. Clinical applications are still under investigation for some selected agents with highly promising initial results. Conclusion Molecular MR imaging shows great potential for the detection, characterization of a wide range of cardiovascular diseases and for monitoring response to therapy. PMID:20539821

  1. 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

  2. Validating Transcripts with Probes and Imaging Technology

    PubMed Central

    Itzkovitz, Shalev; van Oudenaarden, Alexander

    2011-01-01

    High throughput gene expression screens provide a quantitative picture of the average expression signature of biological samples. However, the analysis of spatial gene expression patterns with single cell resolution requires quantitative in-situ measurement techniques. Here we describe recent technological advances in RNA fluorescent in-situ hybridization (FISH) techniques that facilitate detection of individual fluorescently labeled mRNA molecules of practically any endogenous gene. These methods, which are based on advances in probe design, imaging technology, and image processing, enable the absolute measurement of transcript abundance in individual cells with single-molecule resolution. PMID:21451512

  3. 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).

  4. 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

  5. Biomedical applications of a new portable Raman imaging probe

    NASA Astrophysics Data System (ADS)

    Sato, Hidetoshi; Tanaka, Takeyuki; Ikeda, Teruki; Wada, Satoshi; Tashiro, Hideo; Ozaki, Yukihiro

    2001-10-01

    This article reports the outline of a new portable Raman imaging probe and its applications. This probe may be the smallest and lightest Raman imaging probe in the world. It is equipped with an interchangeable long-working distance microscope objective lens. The irradiation area is about 45 and 90 μm and the spatial resolution is 1 μm. In the present study, the Raman imaging probe was used to obtain a Raman image of diamond particles and a Raman mapping of carotenoid in Euglena.

  6. 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).

  7. Raman tags: Novel optical probes for intracellular sensing and imaging.

    PubMed

    Li, Yuee; Wang, Zhong; Mu, Xijiao; Ma, Aning; Guo, Shu

    Optical labels are needed for probing specific target molecules in complex biological systems. As a newly emerging category of tags for molecular imaging in live cells, the Raman label attracts much attention because of the rich information obtained from targeted and untargeted molecules by detecting molecular vibrations. Here, we list three types of Raman probes based on different mechanisms: Surface Enhanced Raman Scattering (SERS) probes, bioorthogonal Raman probes, and Resonance Raman (RR) probes. We review how these Raman probes work for detecting and imaging proteins, nucleic acids, lipids, and other biomolecules in vitro, within cells, or in vivo. We also summarize recent noteworthy studies, expound on the construction of every type of Raman probe and operating principle, sum up in tables typically targeting molecules for specific binding, and provide merits, drawbacks, and future prospects for the three Raman probes.

  8. Instrumentation and probes for molecular and cellular imaging.

    PubMed

    Lecchi, M; Ottobrini, L; Martelli, C; Del Sole, A; Lucignani, G

    2007-06-01

    Molecular and cellular imaging is a branch of biomedical sciences that combines the use of imaging instrumentation and biotechnology to characterize molecular and cellular processes in living organisms in normal and pathologic conditions. The two merging areas of research behind molecular and cellular imaging are detection technology, i.e. scanners and imaging devices, and development of tracers, contrast agents and reporter probes that make imaging with scanners and devices possible. Several in vivo imaging instruments currently used in human studies, such as computer tomography, ultrasound, magnetic resonance, positron emission tomography and single photon emission computed tomography, have been rescaled for small animal studies, while other methods initially used for in vitro evaluation, such as bioluminescence and fluorescence, have been refined for in vivo imaging. Conventional imaging relies on the use of non specific contrast agents and classical probes; however, newly developed targeted contrast agents and activable ''smart'' imaging probes for so-called ''targeted imaging'' have demonstrated high specificity and high signal to noise ratio in small animal studies. This review focuses on basic recent findings in the technical aspects of molecular and cellular imaging modalities (equipment, targeted probe and contrast agents and applied combinations of instrumentation and probe) with particular attention to the choice of the future: the multimodal imaging approach.

  9. 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.

  10. Probing the Double Layer: Effect of Image Forces on AFM

    PubMed Central

    Sachs, Frederick

    2006-01-01

    Force probes such as AFM tips or laser trap latex beads have a dielectric constant much less than that of the water that they displace. Thus when a probe approaches a charged surface under water it will be repelled simply based upon the image forces, and these can be of nN magnitude. PMID:16714346

  11. 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.

  12. Second-harmonic radiating imaging probes and harmonic holography

    NASA Astrophysics Data System (ADS)

    Pu, Ye; Psaltis, Demetri

    2016-10-01

    Compared with other imaging probes such as fluorescent dyes and quantum dots, second-harmonic radiating imaging probes (SHRIMPs) provide a unique ultrafast, coherent optical contrast that is free of photobleaching and emission intermittency. Using the second-harmonic signal emitted from SHRIMPs, harmonic holography achieves threedimensional holographic imaging with a color contrast similar to fluorescence microscopy where the uninterested background scattering is efficiently suppressed by an optical filter. The coherent contrast provided by SHRIMPs also enables imaging through turbid media via digital phase conjugation. Here we review the developments and applications of SHRIMPs and harmonic holography.

  13. 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

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

    PubMed

    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.

  15. 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.

  16. Small Molecule Probes for Plant Cell Wall Polysaccharide Imaging

    PubMed Central

    Wallace, Ian S.; Anderson, Charles T.

    2012-01-01

    Plant cell walls are composed of interlinked polymer networks consisting of cellulose, hemicelluloses, pectins, proteins, and lignin. The ordered deposition of these components is a dynamic process that critically affects the development and differentiation of plant cells. However, our understanding of cell wall synthesis and remodeling, as well as the diverse cell wall architectures that result from these processes, has been limited by a lack of suitable chemical probes that are compatible with live-cell imaging. In this review, we summarize the currently available molecular toolbox of probes for cell wall polysaccharide imaging in plants, with particular emphasis on recent advances in small molecule-based fluorescent probes. We also discuss the potential for further development of small molecule probes for the analysis of cell wall architecture and dynamics. PMID:22639673

  17. 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.

  18. Fluorescent cyanine probe for DNA detection and cellular imaging

    NASA Astrophysics Data System (ADS)

    Zheng, Yong-Chao; Zheng, Mei-Ling; Zhao, Zhen-Sheng; Duan, Xuan-Ming

    2014-03-01

    In our study, two carbazole-based cyanines, 3,6-bis[2-(1-methylpyridinium)vinyl]-9-methyl carbazole diiodide (A) and 6,6'-bis[2-(1-methylpyridinium)vinyl]-bis(9-methyl-carbazol-3yl)methane diiodide (B) were synthesized and employed as light-up probes for DNA and cell imaging. Both of the cyanine probes possess a symmetric structure and bis-cationic center. The obvious induced circular dichroism signals in circular dichroism spectra reveal that the molecules can specifically interact with DNA. Strong fluorescence enhancement is observed when these two cyanines are bound to DNA. These cyanine probes show high binding affinity to oligonucleotides but different binding preferences to various secondary structures. Confocal microscopy images of fixed cell stained by the probes exhibit strong brightness and high contrast in nucleus with a very low cytoplasmic background.

  19. Probing bacterial cell biology using image cytometry.

    PubMed

    Cass, Julie A; Stylianidou, Stella; Kuwada, Nathan J; Traxler, Beth; Wiggins, Paul A

    2017-03-01

    Advances in automated fluorescence microscopy have made snapshot and time-lapse imaging of bacterial cells commonplace, yet fundamental challenges remain in analysis. The vast quantity of data collected in high-throughput experiments requires a fast and reliable automated method to analyze fluorescence intensity and localization, cell morphology and proliferation as well as other descriptors. Inspired by effective yet tractable methods of population-level analysis using flow cytometry, we have developed a framework and tools for facilitating analogous analyses in image cytometry. These tools can both visualize and gate (generate subpopulations) more than 70 cell descriptors, including cell size, age and fluorescence. The method is well suited to multi-well imaging, analysis of bacterial cultures with high cell density (thousands of cells per frame) and complete cell cycle imaging. We give a brief description of the analysis of four distinct applications to emphasize the broad applicability of the tool.

  20. Effect of probe diffusion on the SOFI imaging accuracy

    PubMed Central

    Vandenberg, Wim; Dedecker, Peter

    2017-01-01

    Live-cell super-resolution fluorescence imaging is becoming commonplace for exploring biological systems, though sample dynamics can affect the imaging quality. In this work we evaluate the effect of probe diffusion on super-resolution optical fluctuation imaging (SOFI), using a theoretical model and numerical simulations based on the imaging of live cells labelled with photochromic fluorescent proteins. We find that, over a range of physiological conditions, fluorophore diffusion results in a change in the amplitude of the SOFI signal. The magnitude of this change is approximately proportional to the on-time ratio of the fluorophores. However, for photochromic fluorescent proteins this effect is unlikely to present a significant distortion in practical experiments in biological systems. Due to this lack of distortions, probe diffusion strongly enhances the SOFI imaging by avoiding spatial undersampling caused by the limited labeling density. PMID:28333166

  1. Dendrimer Probes for Enhanced Photostability and Localization in Fluorescence Imaging

    PubMed Central

    Kim, Younghoon; Kim, Sung Hoon; Tanyeri, Melikhan; Katzenellenbogen, John A.; Schroeder, Charles M.

    2013-01-01

    Recent advances in fluorescence microscopy have enabled high-resolution imaging and tracking of single proteins and biomolecules in cells. To achieve high spatial resolutions in the nanometer range, bright and photostable fluorescent probes are critically required. From this view, there is a strong need for development of advanced fluorescent probes with molecular-scale dimensions for fluorescence imaging. Polymer-based dendrimer nanoconjugates hold strong potential to serve as versatile fluorescent probes due to an intrinsic capacity for tailored spectral properties such as brightness and emission wavelength. In this work, we report a new, to our knowledge, class of molecular probes based on dye-conjugated dendrimers for fluorescence imaging and single-molecule fluorescence microscopy. We engineered fluorescent dendritic nanoprobes (FDNs) to contain multiple organic dyes and reactive groups for target-specific biomolecule labeling. The photophysical properties of dye-conjugated FDNs (Cy5-FDNs and Cy3-FDNs) were characterized using single-molecule fluorescence microscopy, which revealed greatly enhanced photostability, increased probe brightness, and improved localization precision in high-resolution fluorescence imaging compared to single organic dyes. As proof-of-principle demonstration, Cy5-FDNs were used to assay single-molecule nucleic acid hybridization and for immunofluorescence imaging of microtubules in cytoskeletal networks. In addition, Cy5-FDNs were used as reporter probes in a single-molecule protein pull-down assay to characterize antibody binding and target protein capture. In all cases, the photophysical properties of FDNs resulted in enhanced fluorescence imaging via improved brightness and/or photostability. PMID:23561533

  2. Magnetically engineered semiconductor quantum dots as multimodal imaging probes.

    PubMed

    Jing, Lihong; Ding, Ke; Kershaw, Stephen V; Kempson, Ivan M; Rogach, Andrey L; Gao, Mingyuan

    2014-10-08

    Light-emitting semiconductor quantum dots (QDs) combined with magnetic resonance imaging contrast agents within a single nanoparticle platform are considered to perform as multimodal imaging probes in biomedical research and related clinical applications. The principles of their rational design are outlined and contemporary synthetic strategies are reviewed (heterocrystalline growth; co-encapsulation or assembly of preformed QDs and magnetic nanoparticles; conjugation of magnetic chelates onto QDs; and doping of QDs with transition metal ions), identifying the strengths and weaknesses of different approaches. Some of the opportunities and benefits that arise through in vivo imaging using these dual-mode probes are highlighted where tumor location and delineation is demonstrated in both MRI and fluorescence modality. Work on the toxicological assessments of QD/magnetic nanoparticles is also reviewed, along with progress in reducing their toxicological side effects for eventual clinical use. The review concludes with an outlook for future biomedical imaging and the identification of key challenges in reaching clinical applications.

  3. Imaging with second-harmonic radiation probes in living tissue

    PubMed Central

    Grange, Rachel; Lanvin, Thomas; Hsieh, Chia-Lung; Pu, Ye; Psaltis, Demetri

    2011-01-01

    We demonstrate that second-harmonic radiation imaging probes are efficient biomarkers for imaging in living tissue. We show that 100 nm and 300 nm BaTiO3 nanoparticles used as contrast markers could be detected through 50 μm and 120 μm of mouse tail tissue in vitro or in vivo. Experimental results and Monte-Carlo simulations are in good agreement. PMID:21991545

  4. The Wide-Field Imager for Solar Probe Plus (WISPR)

    NASA Astrophysics Data System (ADS)

    Vourlidas, Angelos; Howard, Russell A.; Plunkett, Simon P.; Korendyke, Clarence M.; Thernisien, Arnaud F. R.; Wang, Dennis; Rich, Nathan; Carter, Michael T.; Chua, Damien H.; Socker, Dennis G.; Linton, Mark G.; Morrill, Jeff S.; Lynch, Sean; Thurn, Adam; Van Duyne, Peter; Hagood, Robert; Clifford, Greg; Grey, Phares J.; Velli, Marco; Liewer, Paulett C.; Hall, Jeffrey R.; DeJong, Eric M.; Mikic, Zoran; Rochus, Pierre; Mazy, Emanuel; Bothmer, Volker; Rodmann, Jens

    2016-12-01

    The Wide-field Imager for Solar PRobe Plus (WISPR) is the sole imager aboard the Solar Probe Plus (SPP) mission scheduled for launch in 2018. SPP will be a unique mission designed to orbit as close as 7 million km (9.86 solar radii) from Sun center. WISPR employs a 95∘ radial by 58∘ transverse field of view to image the fine-scale structure of the solar corona, derive the 3D structure of the large-scale corona, and determine whether a dust-free zone exists near the Sun. WISPR is the smallest heliospheric imager to date yet it comprises two nested wide-field telescopes with large-format (2 K × 2 K) APS CMOS detectors to optimize the performance for their respective fields of view and to minimize the risk of dust damage, which may be considerable close to the Sun. The WISPR electronics are very flexible allowing the collection of individual images at cadences up to 1 second at perihelion or the summing of multiple images to increase the signal-to-noise when the spacecraft is further from the Sun. The dependency of the Thomson scattering emission of the corona on the imaging geometry dictates that WISPR will be very sensitive to the emission from plasma close to the spacecraft in contrast to the situation for imaging from Earth orbit. WISPR will be the first `local' imager providing a crucial link between the large-scale corona and the in-situ measurements.

  5. Probe reconstruction for holographic X-ray imaging

    PubMed Central

    Hagemann, Johannes; Robisch, Anna-Lena; Osterhoff, Markus; Salditt, Tim

    2017-01-01

    In X-ray holographic near-field imaging the resolution and image quality depend sensitively on the beam. Artifacts are often encountered due to the strong focusing required to reach high resolution. Here, two schemes for reconstructing the complex-valued and extended wavefront of X-ray nano-probes, primarily in the planes relevant for imaging (i.e. focus, sample and detection plane), are presented and compared. Firstly, near-field ptychography is used, based on scanning a test pattern laterally as well as longitudinally along the optical axis. Secondly, any test pattern is dispensed of and the wavefront reconstructed only from data recorded for different longitudinal translations of the detector. For this purpose, an optimized multi-plane projection algorithm is presented, which can cope with the numerically very challenging setting of a divergent wavefront emanating from a hard X-ray nanoprobe. The results of both schemes are in very good agreement. The probe retrieval can be used as a tool for optics alignment, in particular at X-ray nanoprobe beamlines. Combining probe retrieval and object reconstruction is also shown to improve the image quality of holographic near-field imaging. PMID:28244446

  6. 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.

  7. 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.

  8. Raman imaging of biofilms using gold sputtered fiber optic probes

    NASA Astrophysics Data System (ADS)

    Christopher, Christina Grace Charlet; Manoharan, Hariharan; Subrahmanyam, Aryasomayajula; Sai, V. V. Raghavendra

    2016-12-01

    In this work we report characterization of bacterial biofilm using gold sputtered optical fiber probe as substrates for confocal Raman spectroscopy measurements. The chemical composition and the heterogeneity of biofilms in the extracellular polymeric substances (EPS) was evaluated. The spatial distribution of bacterial biofilm on the substrates during their growth phase was studied using Raman imaging. Further, the influence of substrate's surface on bacterial adhesion was investigated by studying growth of biofilms on surfaces with hydrophilic and hydrophobic coatings. This study validates the use of gold sputtered optical fiber probes as SERS substrates in confocal microscopic configuration to identify and characterize clinically relevant biofilms.

  9. Two-photon fluorescent probe for cadmium imaging in cells.

    PubMed

    Liu, Yongyou; Dong, Xiaohu; Sun, Jian; Zhong, Cheng; Li, Boheng; You, Ximeng; Liu, Bifeng; Liu, Zhihong

    2012-04-21

    A novel two-photon excited fluorescent probe for cadmium (named as TPCd) was designed and synthesized utilizing a prodan (6-acetyl-2-methoxynaphthalene) derivative as the two-photon fluorophore and an o-phenylenediamine derivative as the Cd(2+) chelator, which possessed favorable photophysical properties and good water-solubility. The probe was designed with a photoinduced electron transfer (PET) mechanism and thus was weakly fluorescent itself. After binding with Cd(2+) which blocked the PET process, the fluorescence intensity of the probe was enhanced by up to 15-fold under one-photon excitation (OPE) and 27-fold under two-photon excitation (TPE), respectively. The two-photon action cross-section (Φδ) of the TPCd-Cd complex at 740 nm reached 109 GM compared to 3.6 GM for free TPCd, indicating the promising prospect of the probe in two-photon application. TPCd chelated Cd(2+) with 1 : 1 stoichiometry, and the apparent dissociation constant (K(d)) was 6.1 × 10(-5) M for the one-photon mode and 7.2 × 10(-5) M for the two-photon mode. The probe responded to Cd(2+) over a wide linear range from 0.1 to 30 μM with a detection limit of 0.04 μM. High selectivity of the probe towards Cd(2+) was acquired in Tris-HCl/sodium phosphate buffer. The probe was pH-independent in the biologically relevant pH range and non-toxic to living cells at reasonable concentration levels, warranting its in vivo applications. Through two-photon microscopy imaging, the probe was successfully applied to detect Cd(2+) uptake in living HepG2 cells.

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

    NASA Astrophysics Data System (ADS)

    Jesse, S.; Vasudevan, R. K.; Collins, L.; Strelcov, E.; Okatan, M. B.; Belianinov, A.; Baddorf, A. P.; Proksch, R.; Kalinin, S. V.

    2014-04-01

    Field confinement at the junction between a biased scanning probe microscope's tip and solid surface enables local probing of various bias-induced transformations, such as polarization switching, ionic motion, and electrochemical reactions. The nanoscale size of the biased region, smaller or comparable to that of features such as 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 approach allows one to link structure to functionality and deterministically decipher associated mesoscopic and atomistic mechanisms. Furthermore, responses measured as a function of frequency and bias can serve as a fingerprint of local material functionality, allowing for local recognition imaging of inorganic and biological systems. This article reviews current progress in multidimensional scanning probe microscopy techniques based on band excitation time and voltage spectroscopies, including discussions on data acquisition, dimensionality reduction, and visualization, along with future challenges and opportunities for the field.

  11. Doped semiconductor nanocrystal based fluorescent cellular imaging probes.

    PubMed

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

    2013-06-21

    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.

  12. 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

  13. 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

  14. Imaging phluorin-based probes at hippocampal synapses.

    PubMed

    Royle, Stephen J; Granseth, Björn; Odermatt, Benjamin; Derevier, Aude; Lagnado, Leon

    2008-01-01

    Accurate measurement of synaptic vesicle exocytosis and endocytosis is crucial to understanding the molecular basis of synaptic transmission. The fusion of a pH-sensitive green fluorescent protein (pHluorin) to various synaptic vesicle proteins has allowed the study of synaptic vesicle recycling in real time. Two such probes, synaptopHluorin and sypHy, have been imaged at synapses of hippocampal neurons in culture. The combination of these reporters with techniques for molecular interference, such as RNAi allows for the study of molecules involved in synaptic vesicle recycling. Here the authors describe methods for the culture and transfection of hippocampal neurons, imaging of pHluorin-based probes at synapses and analysis of pHluorin signals down to the resolution of individual synaptic vesicles.

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

    SciTech Connect

    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.

  16. What do users really perceive: probing the subjective image quality

    NASA Astrophysics Data System (ADS)

    Nyman, Göte; Radun, Jenni; Leisti, Tuomas; Oja, Joni; Ojanen, Harri; Olives, Jean-Luc; Vuori, Tero; Häkkinen, Jukka

    2006-01-01

    Image evaluation schemes must fulfill both objective and subjective requirements. Objective image quality evaluation models are often preferred over subjective quality evaluation, because of their fastness and cost-effectiveness. However, the correlation between subjective and objective estimations is often poor. One of the key reasons for this is that it is not known what image features subjects use when they evaluate image quality. We have studied subjective image quality evaluation in the case of image sharpness. We used an Interpretation-based Quality (IBQ) approach, which combines both qualitative and quantitative approaches to probe the observer's quality experience. Here we examine how naive subjects experienced and classified natural images, whose sharpness was changing. Together the psychometric and qualitative information obtained allows the correlation of quantitative evaluation data with its underlying subjective attribute sets. This offers guidelines to product designers and developers who are responsible for image quality. Combining these methods makes the end-user experience approachable and offers new ways to improve objective image quality evaluation schemes.

  17. 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.

  18. DNA nanostructure-based imaging probes and drug carriers.

    PubMed

    Zhan, Pengfei; Jiang, Qiao; Wang, Zhen-Gang; Li, Na; Yu, Haiyin; Ding, Baoquan

    2014-09-01

    Self-assembled DNA nanostructures are well-defined nanoscale shapes, with uniform sizes, precise spatial addressability, and excellent biocompatibility. With these features, DNA nanostructures show great potential for biomedical applications; various DNA-based biomedical imaging probes or payload delivery carriers have been developed. In this review, we summarize the recent developments of DNA-based nanostructures as tools for diagnosis and cancer therapy. The biological effects that are brought about by DNA nanostructures are highlighted by in vitro and in vivo imaging, antitumor drug delivery, and immunostimulatory therapy. The challenges and perspectives of DNA nanostructures in the field of nanomedicine are discussed.

  19. 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

  20. 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.

  1. Localized charge imaging with scanning Kelvin probe microscopy

    NASA Astrophysics Data System (ADS)

    Orihuela, M. F.; Somoza, A. M.; Colchero, J.; Ortuño, M.; Palacios-Lidón, E.

    2017-01-01

    In this work, we propose an intuitive and easily implementable approach to model and interpret scanning Kelvin probe microscopy images of insulating samples with localized charges. The method, based on the image charges method, has been validated by a systematic comparison of its predictions with experimental measurements performed on charge domains of different sizes, injected in polymethyl methacrylate discontinuous films. The agreement between predictions and experimental lateral profiles, as well as with spectroscopy tip-sample distance curves, supports its consistency. The proposed procedure allows obtaining quantitative information such as total charge and the size of a charge domain and allows estimating the most adequate measurement parameters.

  2. KRAS and BRAF Mutations and PTEN Expression Do Not Predict Efficacy of Cetuximab-Based Chemoradiotherapy in Locally Advanced Rectal Cancer

    SciTech Connect

    Erben, Philipp; Stroebel, Philipp; Horisberger, Karoline; Popa, Juliana; Bohn, Beatrice; Hanfstein, Benjamin; Kaehler, Georg; Kienle, Peter; Post, Stefan; Wenz, Frederik; Hochhaus, Andreas

    2011-11-15

    Purpose: Mutations in KRAS and BRAF genes as well as the loss of expression of phosphatase and tensin homolog (PTEN) (deleted on chromosome 10) are associated with impaired activity of antibodies directed against epidermal growth factor receptor in patients with metastatic colorectal cancer. The predictive and prognostic value of the KRAS and BRAF point mutations as well as PTEN expression in patients with locally advanced rectal cancer (LARC) treated with cetuximab-based neoadjuvant chemoradiotherapy is unknown. Methods and Materials: We have conducted phase I and II trials of the combination of weekly administration of cetuximab and irinotecan and daily doses of capecitabine in conjunction with radiotherapy (45 Gy plus 5.4 Gy) in patients with LARC (stage uT3/4 or uN+). The status of KRAS and BRAF mutations was determined with direct sequencing, and PTEN expression status was determined with immunohistochemistry testing of diagnostic tumor biopsies. Tumor regression was evaluated by using standardized regression grading, and disease-free survival (DFS) was calculated according to the Kaplan-Meier method. Results: A total of 57 patients were available for analyses. A total of 31.6% of patients carried mutations in the KRAS genes. No BRAF mutations were found, while the loss of PTEN expression was observed in 9.6% of patients. Six patients achieved complete remission, and the 3-year DFS rate was 73%. No correlation was seen between tumor regression or DFS rate and a single marker or a combination of all markers. Conclusions: In the present series, no BRAF mutation was detected. The presence of KRAS mutations and loss of PTEN expression were not associated with impaired response to cetuximab-based chemoradiotherapy and 3-year DFS.

  3. Probing synaptic function in dendrites with calcium imaging.

    PubMed

    Siegel, Friederike; Lohmann, Christian

    2013-04-01

    Calcium imaging has become a widely used technique to probe neuronal activity on the cellular and subcellular levels. In contrast to standard electrophysiological methods, calcium imaging resolves sub- and suprathreshold activation patterns in structures as small as fine dendritic branches and spines. This review highlights recent findings gained on the subcellular level using calcium imaging, with special emphasis on synaptic transmission and plasticity in individual spines. Since imaging allows monitoring activity across populations of synapses, it has recently been adopted to investigate how dendrites integrate information from many synapses. Future experiments, ideally carried out in vivo, will reveal how the dendritic tree integrates and computes afferent signals. For example, it is now possible to directly test the concept that dendritic inputs are clustered and that single dendrites or dendritic stretches act as independent computational units.

  4. Advances in Imaging Techniques and Genetically Encoded Probes for Photoacoustic Imaging

    PubMed Central

    Liu, Chengbo; Gong, Xiaojing; Lin, Riqiang; Liu, Feng; Chen, Jingqin; Wang, Zhiyong; Song, Liang; Chu, Jun

    2016-01-01

    Photoacoustic (PA) imaging is a rapidly emerging biomedical imaging modality that is capable of visualizing cellular and molecular functions with high detection sensitivity and spatial resolution in deep tissue. Great efforts and progress have been made on the development of various PA imaging technologies with improved resolution and sensitivity over the past two decades. Various PA probes with high contrast have also been extensively developed, with many important biomedical applications. In comparison with chemical dyes and nanoparticles, genetically encoded probes offer easier labeling of defined cells within tissues or proteins of interest within a cell, have higher stability in vivo, and eliminate the need for delivery of exogenous substances. Genetically encoded probes have thus attracted increasing attention from researchers in engineering and biomedicine. In this review, we aim to provide an overview of the existing PA imaging technologies and genetically encoded PA probes, and describe further improvements in PA imaging techniques and the near-infrared photochromic protein BphP1, the most sensitive genetically encoded probe thus far, as well as the potential biomedical applications of BphP1-based PA imaging in vivo. PMID:27877244

  5. 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

  6. An enzymatically activated fluorescence probe for targeted tumor imaging

    PubMed Central

    Kamiya, Mako; Kobayashi, Hisataka; Hama, Yukihiro; Koyama, Yoshinori; Bernardo, Marcelino; Nagano, Tetsuo; Choyke, Peter L.; Urano, Yasuteru

    2008-01-01

    β-Galactosidase is a widely used reporter enzyme, but although several substrates are available for in vitro detection, its application for in vivo optical imaging remains a challenge. To obtain a probe suitable for in vivo use, we modified our previously developed activatable fluorescence probe, TG-βGal (J. Am. Chem. Soc., 2005, 127, 4888-4894), on the basis of photochemical and photophysical experiments. The new probe, AM-TG-βGal, provides a dramatic fluorescence enhancement upon reaction with β-galactosidase, and further hydrolysis of the ester moiety by ubiquitous intracellular esterases affords a hydrophilic product that is well retained within the cells without loss of fluorescence. We used a mouse tumor model to assess the practical utility of AM-TG-βGal, after confirming that tumors in the model could be labeled with avidin-β-galactosidase conjugate. This conjugate was administered to the mice in vivo, followed by AM-TG-βGal, and subsequent ex vivo fluorescence imaging clearly visualized intraperitoneal tumors as small as 200 μm. This strategy has potential clinical application, for example in video-assisted laparoscopic tumor resection. PMID:17352471

  7. Photonic Doppler velocimetry lens array probe incorporating stereo imaging

    DOEpatents

    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.

  8. Fluorescent probes for super-resolution imaging in living cells.

    PubMed

    Fernández-Suárez, Marta; Ting, Alice Y

    2008-12-01

    In 1873, Ernst Abbe discovered that features closer than approximately 200 nm cannot be resolved by lens-based light microscopy. In recent years, however, several new far-field super-resolution imaging techniques have broken this diffraction limit, producing, for example, video-rate movies of synaptic vesicles in living neurons with 62 nm spatial resolution. Current research is focused on further improving spatial resolution in an effort to reach the goal of video-rate imaging of live cells with molecular (1-5 nm) resolution. Here, we describe the contributions of fluorescent probes to far-field super-resolution imaging, focusing on fluorescent proteins and organic small-molecule fluorophores. We describe the features of existing super-resolution fluorophores and highlight areas of importance for future research and development.

  9. 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.

  10. A peptide probe for targeted brown adipose tissue imaging.

    PubMed

    Azhdarinia, Ali; Daquinag, Alexes C; Tseng, Chieh; Ghosh, Sukhen C; Ghosh, Pradip; Amaya-Manzanares, Felipe; Sevick-Muraca, Eva; Kolonin, Mikhail G

    2013-01-01

    The presence of brown adipose tissue responsible for thermogenic energy dissipation has been revealed in adult humans and has high clinical importance. Owing to limitations of current methods for brown adipose tissue detection, analysing the abundance and localization of brown adipose tissue in the body has remained challenging. Here we screen a combinatorial peptide library in mice and characterize a peptide (with the sequence CPATAERPC) that selectively binds to the vascular endothelium of brown adipose tissue, but not of intraperitoneal white adipose tissue. We show that in addition to brown adipose tissue, this peptide probe also recognizes the vasculature of brown adipose tissue-like depots of subcutaneous white adipose tissue. Our results indicate that the CPATAERPC peptide localizes to brown adipose tissue even in the absence of sympathetic nervous system stimulation. Finally, we demonstrate that this probe can be used to identify brown adipose tissue depots in mice by whole-body near-infrared fluorescence imaging.

  11. Development of in situ Imaging Probe for Surgical Operation of Deep Brain Stimulation

    NASA Astrophysics Data System (ADS)

    Noda, Toshihiko; Yi-Li, Pan; Tagawa, Ayato; Kobayashi, Takuma; Sasagawa, Kiyotaka; Tokuda, Takashi; Hatanaka, Yumiko; Nakano, Naoki; Kato, Amami; Shiosaka, Sadao; Ohta, Jun

    A novel clinical medical tool for surgical operation of deep brain stimulation was fabricated and evaluated. Dedicated micro-CMOS image sensor was mounted on the tip of quite fine probe tube. The probe has the same diameter as a probe that is utilized in surgical operation. A light source LED was also mounted on the tip of probe. Imaging trial using a postmortem brain was performed with the fabricated probe. The probe can be inserted into a brain easily and take still images of the brain.

  12. Near-infrared dyes for molecular probes and imaging

    NASA Astrophysics Data System (ADS)

    Patonay, Gabor; Beckford, Garfield; Strekowski, Lucjan; Henary, Maged; Kim, Jun Seok; Crow, Sidney

    2009-02-01

    Near-Infrared (NIR) fluorescence has been used both as an analytical tool as molecular probes and in in vitro or in vivo imaging of individual cells and organs. The NIR region (700-1100 nm) is ideal with regard to these applications due to the inherently lower background interference and the high molar absorptivities of NIR chromophores. NIR dyes are also useful in studying binding characteristics of large biomolecules, such as proteins. Throughout these studies, different NIR dyes have been evaluated to determine factors that control binding to biomolecules, including serum albumins. Hydrophobic character of NIR dyes were increased by introducing alkyl and aryl groups, and hydrophilic moieties e.g., polyethylene glycols (PEG) were used to increase aqueous solubility. Recently, our research group introduced bis-cyanines as innovative NIR probes. Depending on their microenvironment, bis-cyanines can exist as an intramolecular dimer with the two cyanines either in a stacked form, or in a linear conformation in which the two subunits do not interact with each other. In this intramolecular H-aggregate, the chromophore has a low extinction coefficient and low fluorescence quantum yield. Upon addition of biomolecules, the H-and D- bands are decreased and the monomeric band is increased, with concomitant increase in fluorescence intensity. Introduction of specific moieties into the NIR dye molecules allows for the development of physiological molecular probes to detect pH, metal ions and other parameters. Examples of these applications include imaging and biomolecule characterizations. Water soluble dyes are expected to be excellent candidates for both in vitro and in vivo imaging of cells and organs.

  13. Glycoproteomic probes for fluorescent imaging of fucosylated glycans in vivo

    PubMed Central

    Sawa, Masaaki; Hsu, Tsui-Ling; Itoh, Takeshi; Sugiyama, Masakazu; Hanson, Sarah R.; Vogt, Peter K.; Wong, Chi-Huey

    2006-01-01

    Glycomics is emerging as a new field for the biology of complex glycoproteins and glycoconjugates. The lack of versatile glycan-labeling methods has presented a major obstacle to visualizing at the cellular level and studying glycoconjugates. To address this issue, we developed a fluorescent labeling technique based on the Cu(I)-catalyzed [3 + 2] cycloaddition, or click chemistry, which allows rapid, versatile, and specific covalent labeling of cellular glycans bearing azide groups. The method entails generating a fluorescent probe from a nonfluorescent precursor, 4-ethynyl-N-ethyl-1,8-naphthalimide, by clicking the fluorescent trigger, the alkyne at the 4 position, with an azido-modified sugar. Using this click-activated fluorescent probe, we demonstrate incorporation of an azido-containing fucose analog into glycoproteins via the fucose salvage pathway. Distinct fluorescent signals were observed by flow cytometry when cells treated with 6-azidofucose were labeled with the click-activated fluorogenic probe or biotinylated alkyne. The intracellular localization of fucosylated glycoconjugates was visualized by using fluorescence microscopy. This technique will allow dynamic imaging of cellular fucosylation and facilitate studies of fucosylated glycoproteins and glycolipids. PMID:16895981

  14. Multistep synthesis of a radiolabeled imaging probe using integrated microfluidics.

    PubMed

    Lee, Chung-Cheng; Sui, Guodong; Elizarov, Arkadij; Shu, Chengyi Jenny; Shin, Young-Shik; Dooley, Alek N; Huang, Jiang; Daridon, Antoine; Wyatt, Paul; Stout, David; Kolb, Hartmuth C; Witte, Owen N; Satyamurthy, Nagichettiar; Heath, James R; Phelps, Michael E; Quake, Stephen R; Tseng, Hsian-Rong

    2005-12-16

    Microreactor technology has shown potential for optimizing synthetic efficiency, particularly in preparing sensitive compounds. We achieved the synthesis of an [(18)F]fluoride-radiolabeled molecular imaging probe, 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG), in an integrated microfluidic device. Five sequential processes-[18F]fluoride concentration, water evaporation, radiofluorination, solvent exchange, and hydrolytic deprotection-proceeded with high radio-chemical yield and purity and with shorter synthesis time relative to conventional automated synthesis. Multiple doses of [18F]FDG for positron emission tomography imaging studies in mice were prepared. These results, which constitute a proof of principle for automated multistep syntheses at the nanogram to microgram scale, could be generalized to a range of radiolabeled substrates.

  15. 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.

  16. 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)

  17. 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

  18. 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.

  19. Analysis of Scanned Probe Images for Magnetic Focusing in Graphene

    NASA Astrophysics Data System (ADS)

    Bhandari, Sagar; Lee, Gil-Ho; Kim, Philip; Westervelt, Robert M.

    2017-02-01

    We have used cooled scanning probe microscopy (SPM) to study electron motion in nanoscale devices. The charged tip of the microscope was raster-scanned at constant height above the surface as the conductance of the device was measured. The image charge scatters electrons away, changing the path of electrons through the sample. Using this technique, we imaged cyclotron orbits that flow between two narrow contacts in the magnetic focusing regime for ballistic hBN-graphene-hBN devices. We present herein an analysis of our magnetic focusing imaging results based on the effects of the tip-created charge density dip on the motion of ballistic electrons. The density dip locally reduces the Fermi energy, creating a force that pushes electrons away from the tip. When the tip is above the cyclotron orbit, electrons are deflected away from the receiving contact, creating an image by reducing the transmission between contacts. The data and our analysis suggest that the graphene edge is rather rough, and electrons scattering off the edge bounce in random directions. However, when the tip is close to the edge, it can enhance transmission by bouncing electrons away from the edge, toward the receiving contact. Our results demonstrate that cooled SPM is a promising tool to investigate the motion of electrons in ballistic graphene devices.

  20. Red Fluorescent Carbon Nanoparticle-Based Cell Imaging Probe.

    PubMed

    Ali, Haydar; Bhunia, Susanta Kumar; Dalal, Chumki; Jana, Nikhil R

    2016-04-13

    Fluorescent carbon nanoparticle-based probes with tunable visible emission are biocompatible, environment friendly and most suitable for various biomedical applications. However, synthesis of red fluorescent carbon nanoparticles and their transformation into functional nanoparticles are very challenging. Here we report red fluorescent carbon nanoparticle-based nanobioconjugates of <25 nm hydrodynamic size and their application as fluorescent cell labels. Hydrophobic carbon nanoparticles are synthesized via high temperature colloid-chemical approach and transformed into water-soluble functional nanoparticles via coating with amphiphilic polymer followed by covalent linking with desired biomolecules. Following this approach, carbon nanoparticles are functionalized with polyethylene glycol, primary amine, glucose, arginine, histidine, biotin and folic acid. These functional nanoparticles can be excited with blue/green light (i.e., 400-550 nm) to capture their emission spanning from 550 to 750 nm. Arginine and folic acid functionalized nanoparticles have been demonstrated as fluorescent cell labels where blue and green excitation has been used for imaging of labeled cells. The presented method can be extended for the development of carbon nanoparticle-based other bioimaging probes.

  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. Molecular Probes for Imaging the Sigma-2 Receptor: In Vitro and In Vivo Imaging Studies.

    PubMed

    Zeng, Chenbo; McDonald, Elizabeth S; Mach, Robert H

    2017-02-08

    The sigma-2 (σ2) receptor has been validated as a biomarker of the proliferative status of solid tumors. Therefore, radiotracers having a high affinity and high selectivity for σ2 receptors have the potential to assess the proliferative status of human tumors using noninvasive imaging techniques such as Positron Emission Tomography (PET). Since the σ2 receptor has not been cloned, the current knowledge of this receptor has relied on receptor binding studies with the radiolabeled probes and investigation of the effects of the σ2 receptor ligands on tumor cells. The development of the σ2 selective fluorescent probes has proven to be useful for studying subcellular localization and biological functions of the σ2 receptor, for revealing pharmacological properties of the σ2 receptor ligands, and for imaging cell proliferation. Preliminary clinical imaging studies with [(18)F]ISO-1, a σ2 receptor probe, have shown promising results in cancer patients. However, the full utility of imaging the σ2 receptor status of solid tumors in the diagnosis and prediction of cancer therapeutic response will rely on elucidation of the functional role of this protein in normal and tumor cell biology.

  3. 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.

  4. 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.

  5. 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.

  6. Multispectral photoacoustic imaging of tumours in mice injected with an enzyme-activatable photoacoustic probe

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

    Photoacoustic (PA) imaging offers depth-resolved images of optical absorbers with the spatial resolution of ultrasound imaging. To enhance tumour contrast, tumour-specific probes are used as contrast agents. We synthesised a colourless PA probe that is activated in the presence of γ-glutamyltranspeptidase, a cancer-associated enzyme, to show its original colour and fluorescence. We have acquired high specificity fluorescence images of small tumours, using a fluorescent probe based on similar enzymatic reactions. Here, we developed a PA imaging technique to detect the PA probe. In PA imaging, depending on the concentration and excitation wavelength of the probe, the intensities of the probe signals may be lower than those of the background signals produced by intrinsic optical absorbers such as haemoglobin. For probe imaging in the presence of strong background signals, multispectral photoacoustic (MS-PA) imaging was evaluated. In MS-PA imaging, the spectral fitting method, which distinguishes the probe signals from background signals using reference spectra, has been widely used. To compensate for the decrease of fluence due to optical attenuation in biological tissue, we used a simplified compensation method that calculates fluence inside biological tissues by the Monte-Carlo model using published data on optical properties of biological tissues. The validity of the method was confirmed using tissue-mimicking phantoms. Finally, MS-PA imaging of a mouse subcutaneous tumour injected with the activatable probe was demonstrated. In conclusion, our MS-PA imaging technique afforded successful detection of the activated probe in the tumour, and time-increase of PA signals were successfully observed.

  7. High-efficiency FRET-enhanced photoacoustic probes for in vivo tumor imaging

    NASA Astrophysics Data System (ADS)

    Qin, Huan; Liu, Liming

    2017-01-01

    Photoacoustic imaging can provide high-resolution and high-contrast image under unprecedented depth compared with pure optical imaging techniques by making use of laser-induced ultrasound waves. Although a series of absorption-enhanced optical contrast agents for photoacoustic imaging were developed, the probe with fully conversion from absorbed light energy to acoustic energy has not been achieved so far. Here we develop a high-efficiency photoacoustic probes with fluorescence resonance energy transfer (FRET) effect for enhancement of nonradiative energy. Graphene oxide (GO) binding optical dyes (GO-dyes) were achieved to show highly fluorescence quenching and violently increased photoacoustic signal intensity. GO-dyes were constructed and testified for multi-spectral photoacoustic imaging. As a representative probe, GO-Cy7 nanoparticles were used to validate the feasibility of photoacoustic tumor molecular imaging in vivo. Our work demonstrated a new approach to construct high-efficiency FRET-enhanced multi-spectrum probes for photoacoustic molecular imaging.

  8. Co-Encapsulating the Fusogenic Peptide INF7 and Molecular Imaging Probes in Liposomes Increases Intracellular Signal and Probe Retention

    PubMed Central

    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

  9. 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

    2014-08-07

    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.

  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. Switchable bi-stable multilayer magnetic probes for imaging of soft magnetic structures.

    PubMed

    Wren, Tom; Puttock, Robb; Gribkov, Boris; Vdovichev, Sergey; Kazakova, Olga

    2017-03-28

    We present the use of custom-made multilayer (ML) magnetic probes in magnetic force microscopy (MFM) for imaging soft magnetic structures, i.e. nickel submicron disks of different dimensions. One of the main advantages of a custom-made ML probe is that it can be controllably switched between standard (parallel) and low moment (antiparallel) states. We demonstrate that the predicted vortex and stripe domain states in the disks are observed when using the ML probes both in the antiparallel and parallel states. However, while the phase contrast is significantly larger in the parallel state, the images are dominated by strong sample - probe interactions that obscure the image. By comparison of the stripe domain width observed by MFM with the ML probe and those expected from the Kittel model, we show that the resolution of the probe in the AP and P states is ∼30-40nm, i.e. of the order of the probe geometrical apex and thus approaching the limit of spatial resolution. The ML probes are further compared to the commercial standard and low moment ones, showing that the quality of images obtained with the ML probe is superior to both commercial probes.

  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. Esophagogastric junction distensibility assessed using the functional lumen imaging probe

    PubMed Central

    Chen, Joan W; Rubenstein, Joel H

    2017-01-01

    AIM To assess reference values in the literature for esophageal distensibility and cross-sectional area in healthy and diseased subjects measured by the functional lumen imaging probe (FLIP). METHODS Systematic search and review of articles in Medline and Embase pertaining to the use of FLIP in the esophagus was conducted in accordance with the PRISMA guidelines. Cross-sectional area and distensibility at the esophagogastric junction (EGJ) were abstracted for normal subjects, achalasia, and gastroesophageal reflux disease (GERD) patients, stratified by balloon length and volume of inflation. RESULTS Six achalasia studies (n = 154), 3 GERD (n = 52), and 5 studies including healthy controls (n = 98) were included in the systematic review. Normative data varied widely amongst studies of healthy volunteers. In contrast, studies in achalasia patients uniformly demonstrated low point estimates in distensibility ≤ 1.6 mm2/mmHg prior to treatment that increased to ≥ 3.4 mm2/mmHg following treatment at 40mL bag volume. In GERD patients, distensibility fell to the range of untreated achalasia (≤ 2.85 mm2/mmHg) following fundoplication. CONCLUSION FLIP may be a useful tool in assessment of treatment efficacy in achalasia. The drastic drop in EGJ distensibility after fundoplication suggests that FLIP measurements need to be interpreted in the context of esophageal body motility and highlights the importance of pre-operative screening for dysmotility. Future studies using standardized FLIP protocol and balloon size are needed. PMID:28275309

  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. 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.

  16. All-optical photoacoustic imaging system using fiber ultrasound probe and hollow optical fiber bundle.

    PubMed

    Miida, Yusuke; Matsuura, Yuji

    2013-09-23

    An all-optical 3D photoacoustic imaging probe that consists of an optical fiber probe for ultrasound detection and a bundle of hollow optical fibers for excitation of photoacoustic waves was developed. The fiber probe for ultrasound is based on a single-mode optical fiber with a thin polymer film attached to the output end surface that works as a Fabry Perot etalon. The input end of the hollow fiber bundle is aligned so that each fiber in the bundle is sequentially excited. A thin and flexible probe can be obtained because the probe system does not have a scanning mechanism at the distal end.

  17. 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.

  18. 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.

  19. Optic probe for multiple angle image capture and optional stereo imaging

    DOEpatents

    Malone, Robert M.; Kaufman, Morris I.

    2016-11-29

    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.

  20. Paired-angle-rotation scanning optical coherence tomography forward-imaging probe

    NASA Astrophysics Data System (ADS)

    Wu, Jigang; Conry, Michael; Gu, Chunhui; Wang, Fei; Yaqoob, Zahid; Yang, Changhuei

    2006-05-01

    We report a novel forward-imaging optical coherence tomography (OCT), needle-probe paired-angle-rotation scanning OCT (PARS-OCT) probe. The probe uses two rotating angled gradient-index lenses to scan the output OCT probe beam over a wide angular arc (˜19° half-angle) of the region forward of the probe. Among other advantages, this probe design is readily amenable to miniaturization and is capable of a variety of scan modes, including volumetric scans. To demonstrate the advantages of the probe design, we have constructed a prototype probe with an outer diameter of 1.65 mm and employed it to acquire four OCT images, with a 45° angle between adjacent images, of the gill structure of a Xenopus laevis tadpole. The system sensitivity was measured to be 93 dB by using the prototype probe with an illumination power of 450 μW on the sample. Moreover, the axial and the lateral resolutions of the probe are 9.3 and 10.3-12.5 μm, respectively.

  1. 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.

  2. 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.

  3. A fluorescent probe for imaging p53-MDM2 protein-protein interaction.

    PubMed

    Liu, Zhenzhen; Miao, Zhenyuan; Li, Jin; Fang, Kun; Zhuang, Chunlin; Du, Lupei; Sheng, Chunquan; Li, Minyong

    2015-04-01

    In this article, we describe a no-wash small-molecule fluorescent probe for detecting and imaging p53-MDM2 protein-protein interaction based on an environment-sensitive fluorescent turn-on mechanism. After extensive biological examination, this probe L1 exhibited practical activity and selectivity in vitro and in cellulo.

  4. 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.

  5. 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.

  6. Synthesis and characterization of novel fluorescent nitrogen-containing bisphosphonate imaging probes for bone active drugs

    PubMed Central

    Sun, Shuting; Błażewska, Katarzyna M.; Kashemirov, Boris A.; Roelofs, Anke J.; Coxon, Fraser P.; Rogers, Michael J.; Ebetino, Frank H.; McKenna, Michael J.; McKenna, Charles E.

    2011-01-01

    Progress in the synthesis of novel fluorescent conjugates of N-heterocyclic bisphosphonate drugs and related analogues, together with some recent applications of these compounds as imaging probes, are briefly discussed. PMID:21894242

  7. A targeted illumination optical fiber probe for high resolution fluorescence imaging and optical switching

    PubMed Central

    Shinde, Anant; Perinchery, Sandeep Menon; Murukeshan, Vadakke Matham

    2017-01-01

    An optical imaging probe with targeted multispectral and spatiotemporal illumination features has applications in many diagnostic biomedical studies. However, these systems are mostly adapted in conventional microscopes, limiting their use for in vitro applications. We present a variable resolution imaging probe using a digital micromirror device (DMD) with an achievable maximum lateral resolution of 2.7 μm and an axial resolution of 5.5 μm, along with precise shape selective targeted illumination ability. We have demonstrated switching of different wavelengths to image multiple regions in the field of view. Moreover, the targeted illumination feature allows enhanced image contrast by time averaged imaging of selected regions with different optical exposure. The region specific multidirectional scanning feature of this probe has facilitated high speed targeted confocal imaging. PMID:28368033

  8. Construction of specific magnetic resonance imaging/optical dual-modality molecular probe used for imaging angiogenesis of gastric cancer.

    PubMed

    Yan, Xuejie; Song, Xiaoyan; Wang, Zhenbo

    2017-05-01

    The purpose of the study was to construct specific magnetic resonance imaging (MRI)/optical dual-modality molecular probe. Tumor-bearing animal models were established. MRI/optical dual-modality molecular probe was construed by coupling polyethylene glycol (PEG)-modified nano-Fe3O4 with specific targeted cyclopeptide GX1 and near-infrared fluorescent dyes Cy5.5. MRI/optical imaging effects of the probe were observed and the feasibility of in vivo double-modality imaging was discussed. It was found that, the double-modality probe was of high stability; tumor signal of the experimental group tended to be weak after injection of the probe, but rose to a level which was close to the previous level after 18 h (p > 0.05). We successively completed the construction of an ideal MRI/optical dual-modality molecular probe. MRI/optical dual-modality molecular probe which can selectively gather in gastric cancer is expected to be a novel probe used for diagnosing gastric cancer in the early stage.

  9. 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.

  10. 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

  11. A resonant scanning dipole-antenna probe for enhanced nanoscale imaging.

    PubMed

    Neumann, Lars; van 't Oever, Jorick; van Hulst, Niek F

    2013-11-13

    We present a scanning antenna probe that provides 35 nm optical hotspots with a 16-fold excitation enhancement. A resonant optical antenna, tuned to operation in the visible, is carved into the aluminum-coated scanning probe. The antenna resonances, field localization, excitation, and polarization response are probed in the near-field by scanning over single fluorescent nanobeads. At the same time, the distance-dependent coupling of the emission to the antenna mode is mapped. Good agreement with theory is obtained. The presented scanning antenna approach is useful for both nanoscale plasmonic mode imaging and (bio)imaging.

  12. 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.

  13. 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.

  14. 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

  15. 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.

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

    PubMed

    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.

  17. 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

  18. Portable oral cancer detection using a miniature confocal imaging probe with a large field of view

    NASA Astrophysics Data System (ADS)

    Wang, Youmin; Raj, Milan; McGuff, H. Stan; Bhave, Gauri; Yang, Bin; Shen, Ting; Zhang, Xiaojing

    2012-06-01

    We demonstrate a MEMS micromirror enabled handheld confocal imaging probe for portable oral cancer detection, where a comparatively large field of view (FOV) was generated through the programmable Lissajous scanning pattern of the MEMS micromirror. Miniaturized handheld MEMS confocal imaging probe was developed, and further compared with the desktop confocal prototype under clinical setting. For the handheld confocal imaging system, optical design simulations using CODE VR® shows the lateral and axial resolution to be 0.98 µm and 4.2 µm, where experimental values were determined to be 3 µm and 5.8 µm, respectively, with a FOV of 280 µm×300 µm. Fast Lissajous imaging speed up to 2 fps was realized with improved Labview and Java based real-time imaging software. Properties such as 3D imaging through autofocusing and mosaic imaging for extended lateral view (6 mm × 8 mm) were examined for carcinoma real-time pathology. Neoplastic lesion tissues of giant cell fibroma and peripheral ossifying fibroma, the fibroma inside the paraffin box and ex vivo gross tissues were imaged by the bench-top and handheld imaging modalities, and further compared with commercial microscope imaging results. The MEMS scanner-based handheld confocal imaging probe shows great promise as a potential clinical tool for oral cancer diagnosis and treatment.

  19. 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.

  20. High-fidelity hydrophilic probe for two-photon fluorescence lysosomal imaging.

    PubMed

    Wang, Xuhua; Nguyen, Dao M; Yanez, Ciceron O; Rodriguez, Luis; Ahn, Hyo-Yang; Bondar, Mykhailo V; Belfield, Kevin D

    2010-09-08

    The synthesis and characterization of a novel two-photon-absorbing fluorene derivative, LT1, selective for the lysosomes of HCT 116 cancer cells, is reported. Linear and nonlinear photophysical and photochemical properties of the probe were investigated to evaluate the potential of the probe for two-photon fluorescence microscopy (2PFM) lysosomal imaging. The cytotoxicity of the probe was investigated to evaluate the potential of using this probe for live two-photon fluorescence biological imaging applications. Colocalization studies of the probe with commercial Lysotracker Red in HCT 116 cells demonstrated the specific localization of the probe in the lysosomes with an extremely high colocalization coefficient (0.96). A figure of merit was introduced to allow comparison between probes. LT1 has a number of properties that far exceed those of commercial lysotracker probes, including higher two-photon absorption cross sections, good fluorescence quantum yield, and, importantly, high photostability, all resulting in a superior figure of merit. 2PFM was used to demonstrate lysosomal tracking with LT1.

  1. Wavelength-Dependent Differential Interference Contrast Microscopy: Selectively Imaging Nanoparticle Probes in Live Cells

    SciTech Connect

    Sun, Wei; Wang, Gufeng; Fang, Ning; and Yeung, Edward S.

    2009-11-15

    Gold and silver nanoparticles display extraordinarily large apparent refractive indices near their plasmon resonance (PR) wavelengths. These nanoparticles show good contrast in a narrow spectral band but are poorly resolved at other wavelengths in differential interference contrast (DIC) microscopy. The wavelength dependence of DIC contrast of gold/silver nanoparticles is interpreted in terms of Mie's theory and DIC working principles. We further exploit this wavelength dependence by modifying a DIC microscope to enable simultaneous imaging at two wavelengths. We demonstrate that gold/silver nanoparticles immobilized on the same glass slides through hybridization can be differentiated and imaged separately. High-contrast, video-rate images of living cells can be recorded both with and without illuminating the gold nanoparticle probes, providing definitive probe identification. Dual-wavelength DIC microscopy thus presents a new approach to the simultaneous detection of multiple probes of interest for high-speed live-cell imaging.

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

    PubMed

    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

    2012-01-01

    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 (18)F-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 (18)F 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 (18)F labeling strategy that employed a much milder phosphate buffer. The (18)F-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

  3. 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

  4. Probing the improbable: imaging carbon atoms in alumina

    SciTech Connect

    Marquis, E A; Yahia, Noor; Larson, David J.; Miller, Michael K; Todd, Richard

    2010-01-01

    Atom-probe tomography has proven very powerful to analyze the detailed structure and chemistry of metallic alloys and semiconductor structures while ceramic materials have remained outside its standard purview. In the current work, we demonstrate that bulk alumina can be quantitatively analyzed and microstructural features observed. The analysis of grain boundary carbon segregation - barely achievable by electron microscopy - opens the possibility of understanding the mechanistic effects of dopants on mechanical properties, fracture and wear properties of bulk oxides.

  5. Two-photon fluorescent probe derived from naphthalimide for cysteine detection and imaging in living cells

    NASA Astrophysics Data System (ADS)

    Liu, Yanbin; Liu, Yuwen; Liu, Wei; Liang, Shucai

    2015-02-01

    A maleimide coupling naphthalimide was reported as new two-photon fluorescent (TPF) probe for cysteine (Cys). The probe was weakly fluorescent itself due to the donor-excited photoinduced electron transfer (d-PET). After reaction with Cys, d-PET process was blocked and fluorescence enhancement of the probe was observed at 470 nm. The d-PET principle was rationalized by theoretical calculations with density functional theory and time-dependent density functional theory. Thiol-maleimide addition between the probe and Cys was confirmed by 1H NMR and mass spectrum measurements. TPF analysis demonstrated a 24.7-fold emission increase of the probe induced by Cys upon excitation at 760 nm. The two-photon action cross-section of probe-Cys adduct at 760 nm reached 42 GM compared to 1.7 GM for free probe. The probe showed high sensitivity and selectivity to Cys over other potential interferences; especially it had the capability to discriminate Cys from glutathione and homocysteine. Through TPF imaging, the probe was successfully applied in the detection of Cys in living cells.

  6. A Novel Method for Imaging Apoptosis Using a Caspase-1 Near-Infrared Fluorescent Probe1

    PubMed Central

    Messerli, Shanta M; Prabhakar, Shilpa; Tang, Yi; Shah, Khalid; Cortes, Maria L; Murthy, Vidya; Weissleder, Ralph; Breakefield, Xandra O; Tung, Ching-Hsuan

    2004-01-01

    Abstract Here we describe a novel method for imaging apoptosis in cells using a near-infrared fluorescent (NIRF) probe selective for caspase-1 (interleukin 1β-converting enzyme, ICE). This biocompatible, optically quenched ICE-NIRF probe incorporates a peptide substrate, which can be selectively cleaved by caspase-1, resulting in the release of fluorescence signal. The specificity of this probe for caspase-1 is supported by various lines of evidence: 1) activation by purified caspase-1, but not another caspase in vitro; 2) activation of the probe by infection of cells with a herpes simplex virus amplicon vector (HGC-ICE-lacZ) expressing a catalytically active caspase-1-lacZ fusion protein; 3) inhibition of HGC-ICE-lacZ vector-induced activation of the probe by coincubation with the caspase-1 inhibitor YVAD-cmk, but not with a caspase-3 inhibitor; and 4) activation of the probe following standard methods of inducing apoptosis with staurosporine, ganciclovir, or ionizing radiation in culture. These results indicate that this novel ICE-NIRF probe can be used in monitoring endogenous and vector-expressed caspase-1 activity in cells. Furthermore, tumor implant experiments indicate that this ICE-NIRF probe can be used to detect caspase-1 activity in living animals. This novel ICE-NIRF probe should prove useful in monitoring endogenous and vector-expressed caspase-1 activity, and potentially apoptosis in cell culture and in vivo. PMID:15140398

  7. 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.

  8. Electromechanical imaging of biomaterials by scanning probe microscopy.

    PubMed

    Rodriguez, B J; Kalinin, S V; Shin, J; Jesse, S; Grichko, V; Thundat, T; Baddorf, A P; Gruverman, A

    2006-02-01

    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-10nm 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.

  9. 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.

  10. Influence of probe-sample temperature difference on thermal mapping contrast in scanning thermal microscopy imaging

    NASA Astrophysics Data System (ADS)

    Kaźmierczak-Bałata, Anna; Juszczyk, Justyna; Trefon-Radziejewska, Dominika; Bodzenta, Jerzy

    2017-03-01

    The purpose of this work is to investigate the influence of a temperature difference through a probe-sample contact on thermal contrast in Scanning Thermal Microscopy imaging. A variety of combinations of temperature differences in the probe-sample system were first analyzed based on an electro-thermal finite element model. The numerical analysis included cooling the sample, as well as heating the sample and the probe. Due to the simplicity in the implementation, experimental verification involved modifying the standard imaging technique by heating the sample. Experiments were carried out in the temperature range between 298 K and 328 K. Contrast in thermal mapping was improved for a low probe current with a heated sample.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. An iminocoumarin benzothiazole-based fluorescent probe for imaging hydrogen sulfide in living cells.

    PubMed

    Zhang, Huatang; Xie, Yusheng; Wang, Ping; Chen, Ganchao; Liu, Ruochuan; Lam, Yun-Wah; Hu, Yi; Zhu, Qing; Sun, Hongyan

    2015-04-01

    Hydrogen sulfide (H2S) has recently been identified as the third gaseous signaling molecule that is involved in regulating many important cellular processes. We report herein a novel fluorescent probe for detecting H2S based on iminocoumarin benzothiazole scaffold. The probe displayed high sensitivity and around 80-fold increment in fluorescence signal after reacting with H2S under physiological condition. The fluorescent intensity of the probe was linearly related to H2S concentration in the range of 0-100 μM with a detection limit of 0.15 μM (3σ/slope). The probe also showed excellent selectivity towards H2S over other biologically relevant species, including ROS, RSS and RNS. Its selectivity for H2S is 32 folds higher than other reactive sulfur species. Furthermore, the probe has been applied for imaging H2S in living cells. Cell imaging experiments demonstrated that the probe is cell-permeable and can be used to monitor the alteration of H2S concentrations in living cells. We envisage that this probe can provide useful tools to further elucidate the biological roles of H2S.

  16. Second harmonic generation at the probe tip for background-free near-field optical imaging.

    PubMed

    Dong, Zhaogang; Soh, Yeng Chai

    2012-08-13

    Second harmonic generation (SHG) has been applied to reduce background signals in near-field optical imaging, but this technique is usually limited to samples with strong second-order nonlinear susceptibilities. To overcome this limitation, in this paper, we present a versatile background-free SHG configuration, where it utilizes the second-order nonlinear susceptibility of the probe which essentially functions as a near-field polarizer capable of filtering out the background signal component. In the theoretical analysis, we first model the probe-sample optical interactions at both the fundamental frequency and the second harmonic frequency by using the coupled dipole method. The theoretical model reveals that the proposed versatile background-free SHG configuration requires two conditions. The first condition is that the incident optical field must be s-polarized. The second condition is that the probe must be made of crystals from symmetry class 222, symmetry class 622, symmetry class 422, symmetry class 42m, symmetry class 43m or symmetry class 23. To demonstrate the effectiveness of the proposed versatile background-free SHG configuration, a probe made of deuterated potassium dideuterium phosphate (DKDP) crystal from symmetry class 42m is analyzed numerically. It is shown that when imaging samples with negligible second-order nonlinear susceptibilities, the proposed background-free SHG configuration improves the imaging contrast by more than one-order of magnitude as compared to all other imaging configurations. Moreover, we also investigate the dependence of its performance on other parameters, such as the probe-sample distance, the relative size between probe and sample, and the tilt angle of probe crystal. It is believed that the proposed configuration could be widely used to achieve high contrast near-field optical imaging.

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

    PubMed

    Carol, Priya; Sreejith, Sivaramapanicker; Ajayaghosh, Ayyappanpillai

    2007-03-05

    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.

  18. 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

  19. 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.

  20. Development of novel nanocarrier-based near-infrared optical probes for in vivo tumor imaging.

    PubMed

    Shimizu, Yoichi; Temma, Takashi; Hara, Isao; Yamahara, Ryo; Ozeki, Ei-ichi; Ono, Masahiro; Saji, Hideo

    2012-03-01

    Optical imaging with near-infrared (NIR) fluorescent probes is a useful diagnostic technology for in vivo tumor detection. Our plan was to develop novel NIR fluorophore-micelle complex probes. IC7-1 and IC7-2 were synthesized as novel lipophilic NIR fluorophores, which were encapsulated in an amphiphilic polydepsipeptide micelle "lactosome". The fluorophore-micelle complexes IC7-1 lactosome and IC7-2 lactosome were evaluated as NIR fluorescent probes for in vivo tumor imaging. IC7-1 and IC7-2 were synthesized and then encapsulated in lactosomes. The optical properties of IC7-1, IC7-2, IC7-1 lactosome and IC7-2 lactosome were measured. IC7-1 lactosome and IC7-2 lactosome were administered to tumor-bearing mice, and fluorescence images were acquired for 48 h. IC7-1 and IC7-2 were successfully synthesized in 12% and 6.3% overall yield, and maximum emission wavelengths in chloroform were observed at 858 nm and 897 nm, respectively. Aqueous buffered solutions of IC7-1 lactosome and IC7-2 lactosome showed similar fluorescence spectra in chloroform and higher or comparable quantum yields and higher photostability compared with ICG. Both lactosome probes specifically visualized tumor tissue 6 h post-administration. IC7-1 lactosome and IC7-2 lactosome could be promising NIR probes for in vivo tumor imaging.

  1. NIR imaging the delivery of cathespin B probe to breast tumors

    NASA Astrophysics Data System (ADS)

    Zhou, Lanlan; Blessington, Dana M.; Zhang, Zhihong; Lindenmayer, Aristid E.; Tung, Ching H.; Weissleder, Ralph; Chance, Britton

    2003-07-01

    Proteases are involved in the invasion and metastasis of tumor cells. Cathepsin B overexpression has been shown in some neoplastic tissues. This study assesses the expression of Cathepsin B in the human fibrosarcoma (HT1080) in the mouse model by near-infrared (NIR) imaging. The nude mice were intravenously injected "a stealth probe" - an activable Cathepsin B sensing near-infrared fluorescence (NIRF) probe (24 hours before sacrifice) and the dye Cy5.5 (30 seconds before sacrifice). The animals were freeze-trapped and NIR images were obtained by the low temperature NIR scanner at the following excitation-emission wavelength pairs: 366, 450nm (NADH), 436, 520nm (FAD), and 670, 695nm (Cathepsin B probe). After imaging, the samples were submitted for histopathological evaluation. The tumor redox ratio NADH/(NADH+FAD) increased significantly because of the hypoxic state of tumor tissue with respect to normal tissue. The Cathepsin B probe was uniformly distributed throughout the tumor. This study indicated the efficient usage of the Cathepsin B probe in the molecular imaging for the detection of the early stage tumors.

  2. Probing the inner gap of a newly imaged debris disk

    NASA Astrophysics Data System (ADS)

    Janson, Markus; Brandt, Tim; Thalmann, Christian; Bonnefoy, Mickael; Carson, Joe; McElwain, Michael; Wisniewski, John; Moro-Martin, Amaya; Buenzli, Esther; Currie, Thayne; Usuda, Tomonori; Tamura, Motohide

    2013-02-01

    HIP 79977 is a young ( 5-10 Myr) star in Upper Scorpius with an infrared excess implying the existence of a debris disk with an inner gap at 40 AU. We recently imaged this disk for the first time with Subaru/HiCIAO, using angular differential imaging (ADI). The images show hints of an inner gap, but a larger field rotation is required for accurately mapping this region of the disk with ADI, which requires a telescope in the Southern hemisphere due to the declination of the target. Here, we propose to use NICI for this purpose. The observations would give a better sense of the disk morphology and may reveal planetary companions in the system, if the gap is dynamically cleared.

  3. In vivo inflammation imaging using a CB2R-targeted near infrared fluorescent probe.

    PubMed

    Zhang, Shaojuan; Shao, Pin; Ling, Xiaoxi; Yang, Ling; Hou, Weizhou; Thorne, Steve H; Beaino, Wissam; Anderson, Carolyn J; Ding, Ying; Bai, Mingfeng

    2015-01-01

    Chronic inflammation is considered as a critical cause of a host of disorders, such as cancer, rheumatoid arthritis, atherosclerosis, and neurodegenerative diseases, although the exact mechanism is yet to be explored. Imaging tools that can specifically target inflammation are therefore important to help reveal the role of inflammation in disease progression, and allows for developing new therapeutic strategies to ultimately improve patient care. The purpose of this study was to develop a new in vivo inflammation imaging approach by targeting the cannabinoid receptor type 2 (CB2R), an emerging inflammation biomarker, using a unique near infrared (NIR) fluorescent probe. Herein, we report the first in vivo CB2R-targeted NIR inflammation imaging study using a synthetic fluorescent probe developed in our laboratory, NIR760-mbc94. In vitro binding assay and fluorescence microscopy study indicate NIR760-mbc94 specifically binds towards CB2R in mouse RAW264.7 macrophage cells. Furthermore, in vivo imaging was performed using a Complete Freund's Adjuvant (CFA)-induced inflammation mouse model. NIR760-mbc94 successfully identified inflamed tissues and the probe uptake was blocked by a CB2R ligand, SR144528. Additionally, immunofluorescence staining in cryosectioned tissues validated the NIR760-mbc94 uptake in inflamed tissues. In conclusion, this study reports the first in vivo CB2R-targeted inflammation imaging using an NIR fluorescent probe. Specific targeting of NIR760-mbc94 has been demonstrated in macrophage cells, as well as a CFA-induced inflammation mouse model. The combined evidence indicates that NIR760-mbc94 is a promising inflammation imaging probe. Moreover, in vivo CB2R-targeted fluorescence imaging may have potential in the study of inflammation-related diseases.

  4. 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

  5. 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

  6. 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

    2016-02-02

    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.

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

    PubMed Central

    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

  8. Multimodal nonlinear endo-microscopy probe design for high resolution, label-free intraoperative imaging

    PubMed Central

    Chen, Xu; Xu, Xiaoyun; McCormick, Daniel T.; Wong, Kelvin; Wong, Stephen T.C.

    2015-01-01

    We present a portable, multimodal, nonlinear endo-microscopy probe designed for intraoperative oncological imaging. Application of a four-wave mixing noise suppression scheme using dual wavelength wave plates (DWW) and a polarization-maintaining fiber improves tissue signal collection efficiency, allowing for miniaturization. The probe, with a small 14 mm transversal diameter, includes a customized miniaturized two-axis MEMS (micro-electromechanical system) raster scanning mirror and micro-optics with an illumination laser delivered by a polarization-maintaining fiber. The probe can potentially be integrated into the arms of a surgical robot, such as da Vinci robotic surgery system, due to its minimal cross sectional area. It has the ability to incorporate multiple imaging modalities including CARS (coherent anti-Stokes Raman scattering), SHG (second harmonic generation), and TPEF (two-photon excited fluorescence) in order to allow the surgeon to locate tumor cells within the context of normal stromal tissue. The resolution of the endo-microscope is experimentally determined to be 0.78 µm, a high level of accuracy for such a compact probe setup. The expected resolution of the as-built multimodal, nonlinear, endo-microscopy probe is 1 µm based on the calculation tolerance allocation using Monte-Carlo simulation. The reported probe is intended for use in laparoscopic or radical prostatectomy, including detection of tumor margins and avoidance of nerve impairment during surgery. PMID:26203361

  9. A fluorogenic probe for imaging protein S-nitrosylation in live cells.

    PubMed

    Shao, Shiyi; Chen, Bo; Cheng, Juan; Wang, Chengkun; Zhang, Yanli; Shao, Lingxiao; Hu, Yongzhou; Han, Yifeng; Han, Feng; Li, Xin

    2017-03-01

    S-nitrosylation is a posttranslational modification of protein cysteine residues leading to the formation of S-nitrosothiols and its detection is crucial to understanding of redox regulation and NO-based signaling. Prototypical detection methods for S-nitrosylation are always carried out ex situ. However, the reversible nature and the tendency of transnitrosylation highlight the necessity of its probing in intact live biological contexts. Herein we provide a fluorogenic chemical probe for the detection of S-nitrosylation in live endothelial cells. The probe is weakly emissive alone and becomes highly fluorescent only after undergoing a reaction with S-nitrosothiols in live cellular environments. This probe features high degrees of specificity and desirable sensitivity. Furthermore, it has been successfully applied to image the dynamic change of protein S-nitrosylation in live endothelial cells. The applicability of the probe in complex biological systems has been additionally verified by imaging a known target of S-nitrosylation, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), in live cells. Due to the versatility exemplified, this probe holds great promise for exploring the role of protein S-nitrosylation in the pathophysiological process of a variety of vascular diseases.

  10. An excited-state intramolecular photon transfer fluorescence probe for localizable live cell imaging of cysteine

    NASA Astrophysics Data System (ADS)

    Liu, Wei; Chen, Wen; Liu, Si-Jia; Jiang, Jian-Hui

    2017-03-01

    Small molecule probes suitable for selective and specific fluorescence imaging of some important but low-concentration intracellular reactive sulfur species such as cysteine (Cys) pose a challenge in chemical biology. We present a readily available, fast-response fluorescence probe CHCQ-Ac, with 2-(5‧-chloro-2-hydroxyl-phenyl)-6-chloro-4(3 H)-quinazolinone (CHCQ) as the fluorophore and acrylate group as the functional moiety, that enables high-selectivity and high-sensitivity for detecting Cys in both solution and biological system. After specifically reacted with Cys, the probe undergoes a seven-membered intramolecular cyclization and released the fluorophore CHCQ with excited-state intramolecular photon transfer effect. A highly fluorescent, insoluble aggregate was then formed to facilitate high-sensitivity and high-resolution imaging. The results showed that probe CHCQ-Ac affords a remarkably large Stokes shift and can detect Cys under physiological pH condition with no interference from other analytes. Moreover, this probe was proved to have excellent chemical stability, low cytotoxicity and good cell permeability. Our design of this probe provides a novel potential tool to visualize and localize cysteine in bioimaging of live cells that would greatly help to explore various Cys-related physiological and pathological cellular processes in cell biology and diagnostics.

  11. Benzothiadiazole Derivatives as Fluorescence Imaging Probes: Beyond Classical Scaffolds.

    PubMed

    Neto, Brenno A D; Carvalho, Pedro H P R; Correa, Jose R

    2015-06-16

    This Account describes the origins, features, importance, and trends of the use of fluorescent small-molecule 2,1,3-benzothiadiazole (BTD) derivatives as a new class of bioprobes applied to bioimaging analyses of several (live and fixed) cell types. BTDs have been successfully used as probes for a plethora of biological analyses for only a few years, and the impressive responses obtained by using this important class of heterocycle are fostering the development of new fluorescent BTDs and expanding the biological applications of such derivatives. The first use of a fluorescent small-molecule BTD derivative as a selective cellular probe dates back to 2010, and since then impressive advances have been described by us and others. The well-known limitations of classical scaffolds urged the development of new classes of bioprobes. Although great developments have been achieved by using classical scaffolds such as coumarins, BODIPYs, fluoresceins, rhodamines, cyanines, and phenoxazines, there is still much to be done, and BTDs aim to succeed where these dyes have shown their limitations. Important organelles and cell components such as nuclear DNA, mitochondria, lipid droplets, and others have already been successfully labeled by fluorescent small-molecule BTD derivatives. New technological systems that use BTDs as the fluorophores for bioimaging experiments have been described in recent scientific literature. The successful application of BTDs as selective bioprobes has led some groups to explore their potential for use in studying membrane pores or tumor cells under hypoxic conditions. Finally, BTDs have also been used as fluorescent tags to investigate the action mechanism of some antitumor compounds. The attractive photophysical data typically observed for π-extended BTD derivatives is fostering interest in the use of this new class of bioprobes. Large Stokes shifts, large molar extinction coefficients, high quantum yields, high stability when stored in solution or

  12. 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.

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

    SciTech Connect

    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 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. 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.

  14. 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.; ...

    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

  15. 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.

  16. Multifunctional Concentric FRET-Quantum Dot Probes for Tracking and Imaging of Proteolytic Activity.

    PubMed

    Massey, Melissa; Li, Jia Jun; Algar, W Russ

    2017-01-01

    Proteolysis has many important roles in physiological regulation. It is involved in numerous cell signaling processes and the pathogenesis of many diseases, including cancers. Methods of visualizing and assaying proteolytic activity are therefore in demand. Förster resonance energy transfer (FRET) probes offer several advantages in this respect. FRET supports end-point or real-time measurements, does not require washing or separation steps, and can be implemented in various assay or imaging formats. In this chapter, we describe methodology for preparing self-assembled concentric FRET (cFRET) probes for multiplexed tracking and imaging of proteolytic activity. The cFRET probe comprises a green-emitting semiconductor quantum dot (QD) conjugated with multiple copies of two different peptide substrates for two target proteases. The peptide substrates are labeled with different fluorescent dyes, Alexa Fluor 555 and Alexa Fluor 647, and FRET occurs between the QD and both dyes, as well as between the two dyes. This design enables a single QD probe to track the activity of two proteases simultaneously. Fundamental cFRET theory is presented, and procedures for using the cFRET probe for quantitative measurement of the activity of two model proteases are given, including calibration, fluorescence plate reader or microscope imaging assays, and data analysis. Sufficient detail is provided for other researchers to adapt this method to their specific requirements and proteolytic systems of interest.

  17. Optimization of a gamma imaging probe for axillary sentinel lymph mapping

    NASA Astrophysics Data System (ADS)

    Georgiou, M.; Loudos, G.; Stratos, D.; Papadimitroulas, P.; Liakou, P.; Georgoulias, P.

    2012-09-01

    Sentinel lymph node (SLN) mapping is a technique for assessing whether early-stage invasive breast cancer has metastasized, thus determining prognosis and treatment options. SLN identification is achieved using the blue-dye and radioactive colloids techniques, which are sometimes combined with lymphoscintigraphy. Furthermore, intra-operative gamma acoustic probes, as well as gamma imaging probes are used during surgery. The purpose of this study is the construction of a gamma probe for sentinel lymph node imaging and its optimization in terms of sensitivity with respect to spatial resolution. The reference probe has small field of view (2.5 × 2.5 cm2) and is based on a position sensitive photomultiplier tube (PSPMT) coupled to a pixellated CsI(Tl) scintillator. Following experimental validation, we simulated the system using the GATE Monte Carlo toolkit (GATE v6.1) and modeled various collimator geometries, in order to evaluate their performance and propose the optimal configuration. The constraints of the proposed gamma imaging probe are i) sensitivity close to 2 cps/kBq and ii) spatial resolution equal to 6 mm at 2 cm source-to-collimator distance and ~ 10 mm at 5 cm. An integrated structure that achieves those requirements is a tungsten collimator with 2 × 2 mm2square holes, 16 mm thickness, 0.15 mm septa, where each CsI(Tl) 2 × 2 × 5 mm3 crystal pixel is placed inside the collimator.

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

    PubMed Central

    Qin, Yi; Hua, Hong

    2016-01-01

    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

  19. 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.

  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. Defect images by planar ECT probe of meander-mesh coils

    SciTech Connect

    Yamada, Sotoshi; Katou, Masaki; Iwahara, Masayoshi; Dawson, F.P.

    1996-09-01

    This paper presents results pertaining to image data obtained from a planar meander-mesh coupled coil type ECT probe. The image data makes it possible to detect not only the existence of a defect but also to extract detailed information regarding the nature of the defect, such as its position, shape, length, and direction. In order to recognize a defect distinctly, the authors have fabricated the high sensitive planar coil which can be used to image a 2-D representation of the ECT signal. The relationships between the image pattern and defect shape are discussed.

  2. Superresolution Imaging of Amyloid Fibrils with Binding-Activated Probes

    PubMed Central

    2013-01-01

    Protein misfolding into amyloid-like aggregates underlies many neurodegenerative diseases. Thus, insights into the structure and function of these amyloids will provide valuable information on the pathological mechanisms involved and aid in the design of improved drugs for treating amyloid-based disorders. However, determining the structure of endogenous amyloids at high resolution has been difficult. Here we employ binding-activated localization microscopy (BALM) to acquire superresolution images of α-synuclein amyloid fibrils with unprecedented optical resolution. We propose that BALM imaging can be extended to study the structure of other amyloids, for differential diagnosis of amyloid-related diseases and for discovery of drugs that perturb amyloid structure for therapy. PMID:23594172

  3. Cross-talk artefacts in Kelvin probe force microscopy imaging: A comprehensive study

    NASA Astrophysics Data System (ADS)

    Barbet, S.; Popoff, M.; Diesinger, H.; Deresmes, D.; Théron, D.; Mélin, T.

    2014-04-01

    We provide in this article a comprehensive study of the role of ac cross-talk effects in Kelvin Probe Force Microscopy (KPFM), and their consequences onto KPFM imaging. The dependence of KPFM signals upon internal parameters such as the cantilever excitation frequency and the projection angle of the KPFM feedback loop is reviewed, and compared with an analytical model. We show that ac cross-talks affect the measured KPFM signals as a function of the tip-substrate distance, and thus hamper the measurement of three-dimensional KPFM signals. The influence of ac cross-talks is also demonstrated onto KPFM images, in the form of topography footprints onto KPFM images, especially in the constant distance (lift) imaging mode. Our analysis is applied to unambiguously probe charging effects in tobacco mosaic viruses (TMVs) in ambient air. TMVs are demonstrated to be electrically neutral when deposited on silicon dioxide surfaces, but inhomogeneously negatively charged when deposited on a gold surface.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. Fluorescence microscopy studies of a peripheral-benzodiazepine-receptor-targeted molecular probe for brain tumor imaging

    NASA Astrophysics Data System (ADS)

    Marcu, Laura; Vernier, P. Thomas; Manning, H. Charles; Salemi, Sarah; Li, Aimin; Craft, Cheryl M.; Gundersen, Martin A.; Bornhop, Darryl J.

    2003-10-01

    This study investigates the potential of a new multi-modal lanthanide chelate complex for specifically targeting brain tumor cells. We report here results from ongoing studies of up-take, sub-cellular localization and binding specificity of this new molecular imaging probe. Fluorescence microscopy investigations in living rat C6 glioma tumor cells demonstrate that the new imaging agent has affinity for glioma cells and binds to mitochondria.

  10. Hand-held probe based optical imaging system towards breast cancer diagnosis

    NASA Astrophysics Data System (ADS)

    Ge, Jiajia; Jayachandran, Bhavani; Regalado, Steven; Zhu, Banghe; Godavarty, Anuradha

    2007-02-01

    Near-infrared (NIR) optical imaging is an emerging noninvasive modality for breast cancer diagnosis. However, the currently available optical imaging systems towards tomography studies are limited either by instrument portability, patient comfort, or flexibility to image any given tissue volume. Herein, a hand-held based optical imaging system is developed such that it can possibly overcome some of the above limitations. The unique features of the hand-held optical probe are: (i) to perform simultaneous multiple point illumination and detection, thus decreasing the total imaging time and improving the overall signal strength; (ii) to adapt to the contour of tissue surface, thus decreasing the leakage of excitation and emission signal at contact surface; and (iii) to obtain trans-illumination measurements apart from reflectance measurements, thus improving the depth information. The increased detected signal strength as well as total interrogated tissue volume is demonstrated by simulation studies (i.e. forward model) over a 5×10×10 cc slab phantom. The appropriate number and layout of the source and detection points on the probe head is determined and the hand-held optical probe is developed. A frequency-domain ICCD (intensified charge coupled device) detection system, which allows simultaneous multiple points detection, is developed and coupled to the hand-held probe in order to perform fluorescence-enhanced optical imaging of tissue phantoms. In the future, imaging of homogenous liquid phantoms will be used for the assessment of this hand-held system, followed by extensive imaging studies on different phantoms types under various experimental conditions.

  11. A new paramagnetically shifted imaging probe for MRI

    PubMed Central

    Senanayake, P. Kanthi; Rogers, Nicola J.; Finney, Katie‐Louise N.A.; Harvey, Peter; Funk, Alexander M.; Wilson, J. Ian; O'Hogain, Dara; Maxwell, Ross; Parker, David

    2016-01-01

    Purpose To develop and characterize a new paramagnetic contrast agent for molecular imaging by MRI. Methods A contrast agent was developed for direct MRI detection through the paramagnetically shifted proton magnetic resonances of two chemically equivalent tert‐butyl reporter groups within a dysprosium(III) complex. The complex was characterized in phantoms and imaged in physiologically intact mice at 7 Tesla (T) using three‐dimensional (3D) gradient echo and spectroscopic imaging (MRSI) sequences to measure spatial distribution and signal frequency. Results The reporter protons reside ∼6.5 Å from the paramagnetic center, resulting in fast T 1 relaxation (T 1 = 8 ms) and a large paramagnetic frequency shift exceeding 60 ppm. Fast relaxation allowed short scan repetition times with high excitation flip angle, resulting in high sensitivity. The large dipolar shift allowed direct frequency selective excitation and acquisition of the dysprosium(III) complex, independent of the tissue water signal. The biokinetics of the complex were followed in vivo with a temporal resolution of 62 s following a single, low‐dose intravenous injection. The lower concentration limit for detection was ∼23 μM. Through MRSI, the temperature dependence of the paramagnetic shift (0.28 ppm.K−1) was exploited to examine tissue temperature variation. Conclusions These data demonstrate a new MRI agent with the potential for physiological monitoring by MRI. Magn Reson Med 77:1307–1317, 2017. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. PMID:26922918

  12. 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

  13. Temperature imaging by 1H NMR and suppression of convection in NMR probes

    PubMed

    Hedin; Furo

    1998-03-01

    A simple arrangement for suppressing convection in NMR probes is tested experimentally. Diffusion experiments are used to determine the onset of convection and 1H temperature imaging helps to rationalize the somewhat surprising results. A convenient new 1H NMR thermometer, CH2Br2 dissolved in a nematic thermotropic liquid crystal, is presented. Copyright 1998 Academic Press.

  14. 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.

  15. Non-invasive Imaging of Idiopathic Pulmonary Fibrosis Using Cathepsin Protease Probes.

    PubMed

    Withana, Nimali P; Ma, Xiaowei; McGuire, Helen M; Verdoes, Martijn; van der Linden, Wouter A; Ofori, Leslie O; Zhang, Ruiping; Li, Hao; Sanman, Laura E; Wei, Ke; Yao, Shaobo; Wu, Peilin; Li, Fang; Huang, Hui; Xu, Zuojun; Wolters, Paul J; Rosen, Glenn D; Collard, Harold R; Zhu, Zhaohui; Cheng, Zhen; Bogyo, Matthew

    2016-01-22

    Idiopathic pulmonary fibrosis (IPF) is a lethal, chronic, progressive disease characterized by formation of scar tissue within the lungs. Because it is a disease of unknown etiology, it is difficult to diagnose, to predict disease course and to devise treatment strategies. Recent evidence suggests that activated macrophages play key roles in the pathology of IPF. Therefore, imaging probes that specifically recognize these pools of activated immune cells could provide valuable information about how these cells contribute to the pathobiology of the disease. Here we demonstrate that cysteine cathepsin-targeted imaging probes can be used to monitor the contribution of macrophages to fibrotic disease progression in the bleomycin-induced murine model of pulmonary fibrosis. Furthermore, we show that the probes highlight regions of macrophage involvement in fibrosis in human biopsy tissues from IPF patients. Finally, we present first-in-human results demonstrating non-invasive imaging of active cathepsins in fibrotic lesions of patients with IPF. Together, our findings validate small molecule cysteine cathepsin probes for clinical PET imaging and suggest that they have the potential to be used to generate mechanistically-informative molecular information regarding cellular drivers of IPF disease severity and progression.

  16. 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.

  17. 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.

  18. A new near-infrared absorption and fluorescent probe based on bombesin for molecular imaging

    NASA Astrophysics Data System (ADS)

    Kujala, Naresh; Zhai, Huifang; Smith, Charles; Prasanphanich, Adam; Sieckman, Gary; Hoffman, Timothy; Volkert, Wynn; Ma, Lixin; Yu, Ping

    2009-02-01

    We have developed a series of new dye bombesin conjugates for site-specific absorption and fluorescence imaging of human prostate and breast cancers. Bombesin (BBN), an amphibian analog to the endogenous ligand, binds to the gastrin releasing peptide (GRP) receptors with high specificity and affinity. Previously, we developed an Alexa Fluor 680-GGG-BBN peptide conjugate which demonstrated high binding affinity and specificity for breast cancer cells in the in vitro and in vivo tests (Ref: Ma et al., Molecular Imaging, vol. 6, no. 3, 2007: 171-180). This probe can not be used as an absorption probe in near-infrared imaging because its absorption peak is in the visible wavelength range. In addition, site specific longer wavelength fluorescent probe is desired for in vivo molecular imaging because long wavelength photons penetrate deeper into tissue. The new absorption and fluorescent probe we developed is based on the last eight-residues of BBN, -Q-W-A-V-G-H-L-M-(NH2), and labeled with AlexaFluor750 through a chemical linker, beta-alanine. The new probe, Alexa Fluor 750-BetaAla-BBN(7-14)NH2, exhibits optimal pharmacokinetics for specific targeting and optical imaging of the GRP receptor over-expressing cancer cells. Absorption spectrum has been measured and showed absorption peaks at 690nm, 720nm and 735nm. Fluorescent band is located at 755nm. In vitro and in vivo investigations have demonstrated the effectiveness of the new conjugates to specifically target human cancer cells overexpressing GRP receptors and tumor xenografts in severely compromised immunodeficient mouse model.

  19. Imaging of homeostatic, neoplastic, and injured tissues by HA-based probes.

    PubMed

    Veiseh, Mandana; Breadner, Daniel; Ma, Jenny; Akentieva, Natalia; Savani, Rashmin C; Harrison, Rene; Mikilus, David; Collis, Lisa; Gustafson, Stefan; Lee, Ting-Yim; Koropatnick, James; Luyt, Leonard G; Bissell, Mina J; Turley, Eva A

    2012-01-09

    An increase in hyaluronan (HA) synthesis, cellular uptake, and metabolism occurs during the remodeling of tissue microenvironments following injury and during disease processes such as cancer. We hypothesized that multimodality HA-based probes selectively target and detectably accumulate at sites of high HA metabolism, thus providing a flexible imaging strategy for monitoring disease and repair processes. Kinetic analyses confirmed favorable available serum levels of the probe following intravenous (i.v.) or subcutaneous (s.c.) injection. Nuclear (technetium-HA, (99m)Tc-HA, and iodine-HA, (125)I-HA), optical (fluorescent Texas Red-HA, TR-HA), and magnetic resonance (gadolinium-HA, Gd-HA) probes imaged liver ((99m)Tc-HA), breast cancer cells/xenografts (TR-HA, Gd-HA), and vascular injury ((125)I-HA, TR-HA). Targeting of HA probes to these sites appeared to result from selective HA receptor-dependent localization. Our results suggest that HA-based probes, which do not require polysaccharide backbone modification to achieve favorable half-life and distribution, can detect elevated HA metabolism in homeostatic, injured, and diseased tissues.

  20. 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

  1. Design optimization and performances of an intraoperative positron imaging probe for radioguided cancer surgery

    NASA Astrophysics Data System (ADS)

    Spadola, S.; Verdier, M.-A.; Pinot, L.; Esnault, C.; Dinu, N.; Charon, Y.; Duval, M.-A.; Ménard, L.

    2016-12-01

    Extent and accuracy of surgical resection is a crucial step in operable tumor therapy. Emergence of promising specific tumor-seeking agents labeled with positron emitters is giving rise to a renewed interest for radioguided surgery using beta probes. Beta detection, due to the particle short range, allows a more sensitive and accurate tumor localization compared to gamma radiotracers. In that context, we are currently developing an intraoperative positron imaging probe using SiPM photosensors to perform tumor localization and post-operative control of the surgical cavity. Because compactness is a key feature when trying to detect positron emitters with high sensitivity in small surgical cavities, we chose to study the simplest detector design based on the use of a very thin organic scintillator coupled to the photosensor. Different designs of the positron imaging probe, including scintillator material and thickness, light spreading window and optical reflector, were investigated with Monte-Carlo simulations and measurements. Their impact on the probe performances were optimized in terms of positron sensitivity, gamma rays background noise contamination, spatial resolution and bias and uniformity. The ability of the probes to detect small radiolabeled tumors was also investigated by simulating different phantom uptake configurations.

  2. Imaging of Homeostatic, Neoplastic, and Injured Tissues by HA-Based Probes

    PubMed Central

    Veiseh, Mandana; Breadner, Daniel; Ma, Jenny; Akentieva, Natalia; Savani, Rashmin C; Harrison, Rene; Mikilus, David; Collis, Lisa; Gustafson, Stefan; Lee, Ting-Yim; Koropatnick, James; Luyt, Leonard G.; Bissell, Mina J.; Turley, Eva A.

    2013-01-01

    An increase in hyaluronan (HA) synthesis, cellular uptake, and metabolism occurs during the remodeling of tissue microenvironments following injury and during disease processes such as cancer. We hypothesized that multimodality HA-based probes selectively target and detectably accumulate at sites of high HA metabolism, thus providing a flexible imaging strategy for monitoring disease and repair processes. Kinetic analyses confirmed favorable available serum levels of the probe following intravenous (i.v.) or subcutaneous (s.c.) injection. Nuclear (technetium-HA, 99mTc-HA, and iodine-HA, 125I-HA), optical (fluorescent Texas Red-HA, TR-HA), and magnetic resonance (gadolinium-HA, Gd-HA) probes imaged liver (99mTc-HA), breast cancer cells/xenografts (TR-HA, Gd-HA), and vascular injury (125I-HA, TR-HA). Targeting of HA probes to these sites appeared to result from selective HA receptor-dependent localization. Our results suggest that HA-based probes, which do not require polysaccharide backbone modification to achieve favorable half-life and distribution, can detect elevated HA metabolism in homeostatic, injured, and diseased tissues. PMID:22066590

  3. 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

  4. 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

  5. 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.

  6. High speed optical coherence microscopy with autofocus adjustment and a miniaturized endoscopic imaging probe

    PubMed Central

    Aguirre, Aaron D.; Sawinski, Juergen; Huang, Shu-Wei; Zhou, Chao; Denk, Winfried; Fujimoto, James G.

    2010-01-01

    Optical coherence microscopy (OCM) is a promising technique for high resolution cellular imaging in human tissues. An OCM system for high-speed en face cellular resolution imaging was developed at 1060 nm wavelength at frame rates up to 5 Hz with resolutions of < 4 µm axial and < 2 µm transverse. The system utilized a novel polarization compensation method to combat wavelength dependent source polarization and achieve broadband electro-optic phase modulation compatible with ultrahigh axial resolution. In addition, the system incorporated an auto-focusing feature that enables precise, near real-time alignment of the confocal and coherence gates in tissue, allowing user-friendly optimization of image quality during the imaging procedure. Ex vivo cellular images of human esophagus, colon, and cervix as well as in vivo results from human skin are presented. Finally, the system design is demonstrated with a miniaturized piezoelectric fiber-scanning probe which can be adapted for laparoscopic and endoscopic imaging applications. PMID:20389435

  7. 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.

  8. Photoacoustic pump-probe tomography of fluorophores in vivo using interleaved image acquisition for motion suppression

    NASA Astrophysics Data System (ADS)

    Märk, Julia; Wagener, Asja; Zhang, Edward; Laufer, Jan

    2017-01-01

    In fluorophores, the excited state lifetime can be modulated using pump-probe excitation. By generating photoacoustic (PA) signals using simultaneous and time-delayed pump and probe excitation pulses at fluences below the maximum permissible exposure, a modulation of the signal amplitude is observed in fluorophores but not in endogenous chromophores. This provides a highly specific contrast mechanism that can be used to recover the location of the fluorophore using difference imaging. The practical challenges in applying this method to in vivo PA tomography include the typically low concentrations of fluorescent contrast agents, and tissue motion. The former results in smaller PA signal amplitudes compared to those measured in blood, while the latter gives rise to difference image artefacts that compromise the unambiguous and potentially noise-limited detection of fluorescent contrast agents. To address this limitation, a method based on interleaved pump-probe image acquisition was developed. It relies on fast switching between simultaneous and time-delayed pump-probe excitation to acquire PA difference signals in quick succession, and to minimise the effects of tissue motion. The feasibility of this method is demonstrated in tissue phantoms and in initial experiments in vivo.

  9. Photoacoustic pump-probe tomography of fluorophores in vivo using interleaved image acquisition for motion suppression

    PubMed Central

    Märk, Julia; Wagener, Asja; Zhang, Edward; Laufer, Jan

    2017-01-01

    In fluorophores, the excited state lifetime can be modulated using pump-probe excitation. By generating photoacoustic (PA) signals using simultaneous and time-delayed pump and probe excitation pulses at fluences below the maximum permissible exposure, a modulation of the signal amplitude is observed in fluorophores but not in endogenous chromophores. This provides a highly specific contrast mechanism that can be used to recover the location of the fluorophore using difference imaging. The practical challenges in applying this method to in vivo PA tomography include the typically low concentrations of fluorescent contrast agents, and tissue motion. The former results in smaller PA signal amplitudes compared to those measured in blood, while the latter gives rise to difference image artefacts that compromise the unambiguous and potentially noise-limited detection of fluorescent contrast agents. To address this limitation, a method based on interleaved pump-probe image acquisition was developed. It relies on fast switching between simultaneous and time-delayed pump-probe excitation to acquire PA difference signals in quick succession, and to minimise the effects of tissue motion. The feasibility of this method is demonstrated in tissue phantoms and in initial experiments in vivo. PMID:28091571

  10. Dual-Modality Activity-Based Probes as Molecular Imaging Agents for Vascular Inflammation.

    PubMed

    Withana, Nimali P; Saito, Toshinobu; Ma, Xiaowei; Garland, Megan; Liu, Changhao; Kosuge, Hisanori; Amsallem, Myriam; Verdoes, Martijn; Ofori, Leslie O; Fischbein, Michael; Arakawa, Mamoru; Cheng, Zhen; McConnell, Michael V; Bogyo, Matthew

    2016-10-01

    Macrophages are cellular mediators of vascular inflammation and are involved in the formation of atherosclerotic plaques. These immune cells secrete proteases such as matrix metalloproteinases and cathepsins that contribute to disease formation and progression. Here, we demonstrate that activity-based probes (ABPs) targeting cysteine cathepsins can be used in murine models of atherosclerosis to noninvasively image activated macrophage populations using both optical and PET/CT methods. The probes can also be used to topically label human carotid plaques demonstrating similar specific labeling of activated macrophage populations.

  11. 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.

  12. Semiconducting polymer nanoparticles as photoacoustic molecular imaging probes in living mice.

    PubMed

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

    2014-03-01

    Photoacoustic 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, photoacoustic molecular imaging probes have to be developed. Here, we introduce near-infrared light absorbing semiconducting polymer nanoparticles as a new class of contrast agents for photoacoustic molecular imaging. These nanoparticles can produce a stronger signal than the commonly used single-walled carbon nanotubes and gold nanorods on a per mass basis, permitting whole-body lymph-node photoacoustic mapping in living mice at a low systemic injection mass. Furthermore, the semiconducting polymer nanoparticles possess high structural flexibility, narrow photoacoustic spectral profiles and strong resistance to photodegradation and oxidation, enabling the development of the first near-infrared ratiometric photoacoustic probe for in vivo real-time imaging of reactive oxygen species--vital chemical mediators of many diseases. These results demonstrate semiconducting polymer nanoparticles to be an ideal nanoplatform for developing photoacoustic molecular probes.

  13. Whole-body kinetic image of a redox probe in mice using Overhauser-enhanced MRI.

    PubMed

    Kosem, Nuttavut; Naganuma, Tatsuya; Ichikawa, Kazuhiro; Phumala Morales, Noppawan; Yasukawa, Keiji; Hyodo, Fuminori; Yamada, Ken-Ichi; Utsumi, Hideo

    2012-07-15

    Overhauser-enhanced MRI (OMRI) enables visualization of free radicals in animals based on dynamic nuclear polarization. Real-time data of tissue redox status gathered from kinetic images of redox-sensitive nitroxyl radical probes using OMRI provided both anatomic and physiological information. Phantom experiments demonstrated the linear correlation between the enhancement factor and the concentration of a membrane-impermeable probe, carboxy-PROXYL (3-carboxy-2,2,5,5-tetramethyl- pyrrolidine-1-oxyl). Whole-body OMRI images illustrated the in vivo kinetics of carboxy-PROXYL for 25 min. Initial distribution was observed in lung, heart, liver, and kidney, but not brain, corresponding to its minimal lipophilicity. Based on these images (pixel size, 1.33 × 1.33 mm; slice thickness, 50mm), a time-concentration curve with low coefficient of variance (<0.21) was created to assess pharmacokinetic behaviors. A biexponential curve showed a distribution phase from 1 to 10 min and an elimination phase from 15 to 25 min. The α rate constant was greater than the β rate constant in ROIs, confirming that its pharmacokinetics obeyed a two-compartment model. As a noninvasive technique, combining OMRI imaging with redox probes to monitor tissue redox status may be useful in acquiring valuable information regarding organ function for preclinical and clinical studies of oxidative diseases.

  14. Semiconducting polymer nanoparticles as photoacoustic molecular imaging probes in living mice

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    Photoacoustic 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, photoacoustic molecular imaging probes have to be developed. Here, we introduce near-infrared light absorbing semiconducting polymer nanoparticles as a new class of contrast agents for photoacoustic molecular imaging. These nanoparticles can produce a stronger signal than the commonly used single-walled carbon nanotubes and gold nanorods on a per mass basis, permitting whole-body lymph-node photoacoustic mapping in living mice at a low systemic injection mass. Furthermore, the semiconducting polymer nanoparticles possess high structural flexibility, narrow photoacoustic spectral profiles and strong resistance to photodegradation and oxidation, enabling the development of the first near-infrared ratiometric photoacoustic probe for in vivo real-time imaging of reactive oxygen species--vital chemical mediators of many diseases. These results demonstrate semiconducting polymer nanoparticles to be an ideal nanoplatform for developing photoacoustic molecular probes.

  15. A sensitive and specific Raman probe based on bisarylbutadiyne for live cell imaging of mitochondria.

    PubMed

    Yamakoshi, Hiroyuki; Palonpon, Almar; Dodo, Kosuke; Ando, Jun; Kawata, Satoshi; Fujita, Katsumasa; Sodeoka, Mikiko

    2015-02-01

    We previously showed that bisarylbutadiyne (BADY), which has a conjugated diyne structure, exhibits an intense peak in the cellular Raman-silent region. Here, we synthesized a mitochondria-selective Raman probe by linking bisphenylbutadiyne with triphenylphosphonium, a well-known mitochondrial targeting moiety. This probe, named MitoBADY, has a Raman peak 27 times more intense than that of 5-ethynyl-2'-deoxyuridine. Raman microscopy using submicromolar extracellular probe concentrations successfully visualized mitochondria in living cells. A full Raman spectrum is acquired at each pixel of the scanned sample, and we showed that simultaneous Raman imaging of MitoBADY and endogenous cellular biomolecules can be achieved in a single scan. MitoBADY should be useful for the study of mitochondrial dynamics.

  16. Multi-scale Imaging of Cellular and Sub-cellular Structures using Scanning Probe Recognition Microscopy.

    NASA Astrophysics Data System (ADS)

    Chen, Q.; Rice, A. F.

    2005-03-01

    Scanning Probe Recognition Microscopy is a new scanning probe capability under development within our group to reliably return to and directly interact with a specific nanobiological feature of interest. In previous work, we have successfully recognized and classified tubular versus globular biological objects from experimental atomic force microscope images using a method based on normalized central moments [ref. 1]. In this paper we extend this work to include recognition schemes appropriate for cellular and sub-cellular structures. Globular cells containing tubular actin filaments are under investigation. Thus there are differences in external/internal shapes and scales. Continuous Wavelet Transform with a differential Gaussian mother wavelet is employed for multi- scale analysis. [ref. 1] Q. Chen, V. Ayres and L. Udpa, ``Biological Investigation Using Scanning Probe Recognition Microscopy,'' Proceedings 3rd IEEE Conference on Nanotechnology, vol. 2, p 863-865 (2003).

  17. 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.

  18. 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.

  19. An Activatable Near Infrared Fluorescent Probe for In Vivo Imaging of Fibroblast Activation Protein-alpha

    PubMed Central

    Li, Jinbo; Chen, Kai; Liu, Hongguang; Cheng, Kai; Yang, Meng; Zhang, Jiping; Cheng, Jonathan D.; Zhang, Yan; Cheng, Zhen

    2012-01-01

    Fibroblast activation protein-alpha (FAPα) is a cell surface glycoprotein which is selectively expressed by tumor-associated fibroblasts in malignant tumors but rarely on normal tissues. FAPα has also been reported to promote tumor growth and invasion and therefore has been of increasing interest as a promising target for designing tumor-targeted drugs and imaging agents. Although medicinal study on FAPα inhibitors has led to the discovery of many FAPα-targeting inhibitors including a drug candidate in a phase II clinical trial, the development of imaging probes to monitor the expression and activity of FAPα in vivo has largely lagged behind. Herein we report an activatable near infrared (NIR) fluorescent probe (ANPFAP) for in vivo optical imaging of FAPα. The ANPFAP consists of a NIR dye (Cy5.5) and a quencher dye (QSY21) which are linked together by a short peptide sequence (KGPGPNQC) specific for FAPα cleavage. Because of the efficient fluorescence resonance energy transfer (FRET) between Cy5.5 and QSY21 in ANPFAP, high contrast on the NIR fluorescence signal can be achieved after the cleavage of the peptide sequence by FAPα both in vitro and in vivo. In vitro assay on ANPFAP indicated the specificity of the probe to FAPα. The in vivo optical imaging using ANPFAP showed fast tumor uptake as well as high tumor to background contrast on U87MG tumor models with FAPα expression, while much lower signal and tumor contrast were observed in the C6 tumor without FAPα expression, demonstrating the in vivo targeting specificity of the ANPFAP. Ex vivo imaging also demonstrated ANPFAP had high tumor uptake at 4 h post injection. Collectively, these results indicated that ANPFAP could serve as a useful NIR optical probe for early detection of FAPα expressing tumors. PMID:22812530

  20. A highly selective fluorescent probe based on coumarin for the imaging of N2H4 in living cells

    NASA Astrophysics Data System (ADS)

    Chen, Song; Hou, Peng; Wang, Jing; Liu, Lei; Zhang, Qi

    2017-02-01

    A turn-on fluorescence probe for highly sensitive and selective detection of N2H4 was developed based on hydrazine-triggered a substitution- cyclization-elimination cascade. Upon the treatment with N2H4, probe 1, 4-methyl-coumarin-7-yl bromobutanoate, displayed a remarkable fluorescence enhancement (25-fold) with a maximum at 450 nm. This probe can quantitatively detect N2H4 with a extremely low detection limit as 7 × 10- 8 M. Moreover, cell imaging experiments have indicated that probe 1 has potential ability to detect and image N2H4 in biological systems.

  1. 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.

  2. Development of an endoscopic fluorescence image-guided OCT probe for oral cancer detection

    NASA Astrophysics Data System (ADS)

    McNichols, Roger J.; Gowda, Ashok; Bell, Brent A.; Johnigan, Richard M.; Calhoun, Karen H.; Motamedi, Massoud

    2001-06-01

    Oral squamous cell carcinoma is a disease which progresses through a number of well-defined morphological and biochemical changes. Optical coherence tomography (OCT) is a rapidly-evolving, non-invasive imaging modality which allows detailed probing of subsurface tissue structures with resolution on the order of microns. While this technique offers tremendous potential as a diagnostic tool for detection and characterization of oral cancer, OCT imaging is presently associated with a field of view on the order of millimeters, and acquisition time on the order of seconds. Thus, OCT's utility as a rapid cancer screening technique is presently limited. On the other hand, imaging of tissue autofluorescence provides a very rapid, high-throughput method for cancer screening. However, while autofluorescence measures may be sensitive to cancer, they are often non- specific and lead to a large number of false positives. In the present work, we have developed a fluorescence image guided optical coherence tomographic (FIG-OCT) probe in which tissue autofluorescence images are simultaneously used to guide OCT image acquisition of suspicious regions in real time. We have begun pre-clinical pilot studies with this instrument in a DMBA-induced model of oral cancer in the hamster cheek pouch. Initial results indicate that the FIG- OCT approach shows promise as a rapid and effective tool for screening of oral cancer.

  3. 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

  4. Pixelation effect removal from fiber bundle probe based optical coherence tomography imaging.

    PubMed

    Han, Jae-Ho; Lee, Junghoon; Kang, Jin U

    2010-03-29

    A method of eliminating pixelization effect from en face optical coherence tomography (OCT) image when a fiber bundle is used as an OCT imaging probe is presented. We have demonstrated that applying a histogram equalization process before performing a weighted-averaged Gaussian smoothing filter to the original lower gray level intensity based image not only removes the structural artifact of the bundle but also enhances the image quality with minimum blurring of object's image features. The measured contrast-to-noise ratio (CNR) for an image of the US Air Force test target was 14.7dB (4.9dB), after (before) image processing. In addition, by performing the spatial frequency analysis based on two-dimensional discrete Fourier transform (2-D DFT), we were able to observe that the periodic intensity peaks induced by the regularly arrayed structure of the fiber bundle can be efficiently suppressed by 41.0dB for the first nearby side lobe as well as to obtain the precise physical spacing information of the fiber grid. The proposed combined method can also be used as a straight forward image processing tool for any imaging system utilizing fiber bundle as a high-resolution imager.

  5. Two photon fluorescence imaging of lipid membrane domains and potentials using advanced fluorescent probes

    NASA Astrophysics Data System (ADS)

    Kilin, Vasyl; Darwich, Zeinab; Richert, Ludovic; Didier, Pascal; Klymchenko, Andrey; Mély, Yves

    2013-02-01

    Biomembranes are ordered and dynamic nanoscale structures critical for cell functions. The biological functions of the membranes strongly depend on their physicochemical properties, such as electrostatics, phase state, viscosity, polarity and hydration. These properties are essential for the membrane structure and the proper folding and function of membrane proteins. To monitor these properties, fluorescence techniques and notably, two-photon microscopy appear highly suited due to their exquisite sensitivity and their capability to operate in complex biological systems, such as living cells and tissues. In this context, we have developed multiparametric environment-sensitive fluorescent probes tailored for precise location in the membrane bilayer. We notably developed probes of the 3-hydroxychromone family, characterized by an excited state intramolecular proton transfer reaction, which generates two tautomeric emissive species with well-separated emission bands. As a consequence, the response of these probes to changes in their environment could be monitored through changes in the ratios of the two bands, as well as through changes in the fluorescence lifetimes. Using two-photon ratiometric imaging and FLIM, these probes were used to monitor the surface membrane potential, and were applied to detect apoptotic cells and image membrane domains.

  6. 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.

  7. 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.

  8. Application of a Scanning Thermal Nano-Probe for Thermal Imaging of High Frequency Active devices

    NASA Astrophysics Data System (ADS)

    Joodaki, Mojtaba; Janus, Pawel; Gotszalk, Teodor; Kompa, Günter; Edinger, Klaus; Rangelow, Ivo W.

    2005-09-01

    The first application of a new thermal nano-probe based on the changes of electrical resistivity of a nanometer-sized filament with temperature has been presented for the thermal imaging of microwave power active devices. The integration of the filament the fabrication process of the novel thermal probe with a spatial resolution better than 80 nm and a thermal resolution of the order of 10-3 K have already been presented in reference [J. Microelectron. Eng. \\textbf{57--58} (2001) 737]. To demonstrate the capability of the novel thermal nano-probe the measurements have been successfully performed on a 30 fingers GaAs metal--semiconductor field-effect transistor (GaAs-MESFET) with a maximum power dissipation of 2.5 W. The bias circuit has been designed to suppress the undesired microwave oscillations in the transistor. In this case the power dissipation is equal to the dc power input. The near-field measurements using the nano-probe are compared with infrared measurement and three-dimensional finite element static thermal simulations. The good agreement between simulations and measurements confirms the high capability of the nono-probe for these applications.

  9. An analysis and optimization of elliptical RF probes used in magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Forbes, Lawrence K.; Crozier, Stuart; Doddrell, David M.

    1996-09-01

    In magnetic resonance imaging of the entire body, it is often desirable to use an elliptical RF probe, rather than a circular one. As an ellipse more closely conforms to the anatomical cross section of the human thorax and head, better filling factors and therefore improved signal-to-noise ratios may be achieved by the use of elliptical RF coils. The probe is usually of bird-cage type, but the rungs are of finite width due to the high-frequency signals involved. This paper presents a method for computing the magnetic fields produced inside elliptical probes, and the current distributions on the rungs. A slotted shield is assumed to surround the probe, and its influence on field homogeneity is studied. In particular, the currents in a 16-runged unshielded elliptical coil of practical interest were determined optimally in one case, using simulated annealing to optimize the homogeneity of the magnetic field within the probe. The effects of a segmented shield of both elliptical and circular cross section on this coil are discussed, and the results are confirmed by experiment.

  10. 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

  11. Vectorial modeling of near-field imaging with uncoated fiber probes: transfer function and resolving power.

    PubMed

    Gregersen, Niels; Tromborg, Bjarne; Bozhevolnyi, Sergey I

    2006-12-01

    Using exact 3D vectorial simulations of radiation coupling into uncoated dielectric fiber probes, we calculate amplitude transfer functions for conical single-mode fiber tips at the light wavelength of 633 nm. The coupling efficiency of glass fiber tips is determined in a wide range of spatial frequencies of the incident radiation for opening angles varying from 30 degrees to 120 degrees . The resolution in near-field imaging with these tips is considered for field distributions limited in both direct and spatial-frequency space. The characteristics of the transfer functions describing the relation between probed optical fields and near-field images are analyzed in detail. The importance of utilizing a perfectly sharp tip is also examined.

  12. New fluorescence imaging probe with high spatial resolution for in vivo applications.

    PubMed

    Bonnans, V; Gharbi, T; Pieralli, C; Wacogne, B; Humbert, Ph

    2004-01-01

    A new fiberized fluorescence imaging probe is presented. This device can potentially be used for a wide range of biological or medical applications. By exploiting the chromatic aberrations of gradient index lenses, the excitation blue or near-UV excitation light is focused on the sample surface, while the red fluorescence signal is efficiently launched back to collecting fibers. The excitation fiber is single mode at the working wavelength so that a resolution of 5 microm is obtained over a scanning area of several square millimeters. Experimental fluorescence images are presented. They concern either self-fabricated fluorescent microsamples or views of leaves that constitute an example of biological tissues analysis. The probe can also be adapted for spectroscopic investigations.

  13. Imaging individual proteins and nanodomains on intact cell membranes with a probe-based optical antenna.

    PubMed

    van Zanten, Thomas S; Lopez-Bosque, Maria J; Garcia-Parajo, Maria F

    2010-01-01

    Optical antennas that confine and enhance electromagnetic fields in a nanometric region hold great potential for nanobioimaging and biosensing. Probe-based monopole optical antennas are fabricated to enhance fields localized to <30 nm near the antenna apex in aqueous conditions. These probes are used under appropriate excitation antenna conditions to image individual antibodies with an unprecedented resolution of 26 +/- 4 nm and virtually no surrounding background. On intact cell membranes in physiological conditions, the obtained resolution is 30 +/- 6 nm. Importantly, the method allows individual proteins to be distinguished from nanodomains and the degree of clustering to be quantified by directly measuring physical size and intensity of individual fluorescent spots. Improved antenna geometries should lead to true live cell imaging below 10-nm resolution with position accuracy in the subnanometric range.

  14. First Results in the Development of a Compton Probe Prototype for Prostate Imaging

    NASA Astrophysics Data System (ADS)

    Llosá, G.

    2004-07-01

    Compton imaging offers the possibility to improve significantly prostate imaging. Current radiotracer techniques, such as PET, SPECT or planar scintigraphy, suffer from photon attenuation in the tissue, poor resolution or low efficiency. The development of a Compton probe employing silicon as scatter detector makes possible to obtain a considerable benefit over present instrumentation. Electronic collimation overcomes the resolution-efficiency tradeoff imposed by mechanical collimators, and due to its near field operation, both high resolution and high counting efficiency can be achieved. Silicon pad sensors and low noise electronics are being optimized for this application. A Compton probe prototype has been developed, proving its viability and enabling further steps towards the construction of a clinical prototype.

  15. 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.

  16. 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

  17. Multiparameter spatio-thermochemical probing of flame–wall interactions advanced with coherent Raman imaging

    DOE PAGES

    Bohlin, Gustav Alexis; Jainski, Christopher; Patterson, Brian D.; ...

    2016-08-10

    Ultrabroadband coherent anti-Stokes Ra man spectroscopy (CARS) has been developed for one -dimensional imaging of temperature and major species distributions simultaneously in the near-wall region of a methane/air flame supported on a side-wall-quenching (SWQ) burner. Automatic temporal and spatial overlap of the ~7 femtosecond pump and Stokes pulses is achieved utilizing a two-beam CARS phase-matching scheme, and the crossed ~75 picosecond probe beam provide s excellent spatial sectioning of the probed location. Concurrent detection of N2, O2, H2, CO, CO2, and CH4 is demonstrated while high-fidelity flame thermometry is assessed from the N2 pure rotational S-branch in a one-dimensional -CARSmore » imaging configuration. A methane/air premixed flame at lean, stoichiometric, and rich conditions ( Φ = 0.83, 1.0 , and 1.2) and Reynolds number = 5,000 is probed as it quenches against a cooled steel side- wall parallel to the flow providing a persistent flame-wall interaction. Here, an imaging resolution of better than 40 μm is achieved across the field -of-view, thus allowing thermochemical states (temperature and major species) of the thermal boundary layer to be resolved to within ~30 μm of the interface.« less

  18. Dark quenched matrix metalloproteinase fluorogenic probe for imaging osteoarthritis development in vivo.

    PubMed

    Lee, Seulki; Park, Kyeongsoon; Lee, Seung-Young; Ryu, Ju Hee; Park, Jong Woong; Ahn, Hyung Jun; Kwon, Ick Chan; Youn, In-Chan; Kim, Kwangmeyung; Choi, Kuiwon

    2008-09-01

    The early detection of osteoarthritis (OA) is currently a key challenge in the field of rheumatology. Biochemical studies of OA have indicated that matrix metalloproteinase-13 (MMP-13) plays a central role in cartilage degradation. In this study, we describe the potential use of a dark-quenched fluorogenic MMP-13 probe to image MMP-13 in both in vitro and rat models. The imaging technique involved using a MMP-13 peptide substrate, near-infrared (NIR) dye, and a NIR dark quencher. The results from this study demonstrate that the use of a dark-quenched fluorogenic probe allows for the visual detection of MMP-13 in vitro and in OA-induced rat models. In particular, by targeting this OA biomarker, the symptoms of the early and late stages of OA can be readily monitored, imaged, and analyzed in a rapid and efficient fashion. We anticipate that this simple and highly efficient fluorogenic probe will assist in the clinical management of patients with OA, not only for early diagnosis but also to assess individual patient responses to new drug treatments.

  19. Multiparameter spatio-thermochemical probing of flame–wall interactions advanced with coherent Raman imaging

    SciTech Connect

    Bohlin, Gustav Alexis; Jainski, Christopher; Patterson, Brian D.; Dreizler, Andreas; Kliewer, Christopher Jesse

    2016-08-10

    Ultrabroadband coherent anti-Stokes Ra man spectroscopy (CARS) has been developed for one -dimensional imaging of temperature and major species distributions simultaneously in the near-wall region of a methane/air flame supported on a side-wall-quenching (SWQ) burner. Automatic temporal and spatial overlap of the ~7 femtosecond pump and Stokes pulses is achieved utilizing a two-beam CARS phase-matching scheme, and the crossed ~75 picosecond probe beam provide s excellent spatial sectioning of the probed location. Concurrent detection of N2, O2, H2, CO, CO2, and CH4 is demonstrated while high-fidelity flame thermometry is assessed from the N2 pure rotational S-branch in a one-dimensional -CARS imaging configuration. A methane/air premixed flame at lean, stoichiometric, and rich conditions ( Φ = 0.83, 1.0 , and 1.2) and Reynolds number = 5,000 is probed as it quenches against a cooled steel side- wall parallel to the flow providing a persistent flame-wall interaction. Here, an imaging resolution of better than 40 μm is achieved across the field -of-view, thus allowing thermochemical states (temperature and major species) of the thermal boundary layer to be resolved to within ~30 μm of the interface.

  20. Scanning probe microscopy of atoms and molecules on insulating films: from imaging to molecular manipulation.

    PubMed

    Meyer, Gerhard; Gross, Leo; Mohn, Fabian; Repp, Jascha

    2012-01-01

    Scanning tunneling microscopy (STM) and atomic force microscopy (AFM) of single atoms and molecules on ultrathin insulating films have led to a wealth of novel observations and insights. Based on the reduced electronic coupling to the metallic substrate, these techniques allow the charge state of individual atoms to be controlled, orbitals of individual molecules to be imaged and metal-molecule complexes to be built up. Near-contact AFM adds the unique capabilities of imaging and probing the chemical structure of single molecules with atomic resolution. With the help of atomic/molecular manipulation techniques, chemical binding processes and molecular switches can be studied in detail.

  1. 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.

  2. Polyelectrolyte carbon quantum-dots: new player as a noninvasive imaging probe in Drosophila.

    PubMed

    Parvin, Nragish; Mandal, Tapas K; Roy, Partha

    2013-10-01

    It is since long that X-ray or magnetic resonance imaging is being used for biomedical diagnosis. But till date noninvasive soft tissue imaging is not very well established. Towards this end the dietary uptake of polyelectrolyte carbon quantum dots (PECQDs) and their uses as a fluorescent probe is a new approach for imaging live specimens. In the present study we demonstrate that polyelectrolyte carbon quantum dots, which are nontoxic and have fluorescence properties can be used for in vivo imaging of internal organs. Carbon quantum dots surface were abound in polymer of free carboxyl groups making it water soluble. Our used PECQDs are less than equal to 50 nm sized and are capable to emit multi colour fluorescence. It is synthesized from waste plant materials like shaded leaves, unused shrubs, herbs etc. An exposure of 1 ppm level of soluble carbon quantum dots for 12 hours in drosophila permitted the fluorescence microscopy imaging of the different stages of their development and their non invasive internal organs without any remarkable toxic effects. Finally the fluorescent material was found to be excreted out of the animals. The current data suggests that visualization of internal organs with a fluorescent probe in live cells could help in determining the efficacy of therapeutic treatments directly without the need of any invasive procedures.

  3. Ultrathin forward-imaging short multimode fiber probe for full-field optical coherence microscopy

    NASA Astrophysics Data System (ADS)

    Sato, Manabu; Saito, Daisuke; Shouji, Kou; Kurotani, Reiko; Abe, Hiroyuki; Nishidate, Izumi

    2016-12-01

    To extend the applications of optical coherence tomography (OCT) to the fields of physiology and clinical medicine, less invasive, robust, and reliable optical probes are required. Thus, we demonstrate an ultrathin forward-imaging short multimode fiber (SMMF) optical coherence microscopy (OCM) probe with a 50 μm core diameter, 125 μm total diameter, and 5.12 mm length. Imaging conditions and magnification were analyzed, and they correspond closely to the measured results. The dispersion of the SMMF was investigated, and the modal dispersion coefficient was found to be 2.3% of the material dispersion coefficient. The axial resolution was minimized at 2.15 μm using a 0.885-mm-thick dispersion compensator. The lateral resolution was evaluated to be 4.38 μm using a test pattern. The contrast of the OCM images was 5.7 times higher than that of the signal images owing to the coherence gate. The depth of focus and diameter of the field of view were measured to be 60 μm and 40-50 μm, respectively. OCM images of the dried fins of small fish (Medaka) were measured and internal structures could be recognized.

  4. Hyperspectral nanoscale imaging on dielectric substrates with coaxial optical antenna scan probes.

    PubMed

    Weber-Bargioni, Alexander; Schwartzberg, Adam; Cornaglia, Matteo; Ismach, Ariel; Urban, Jeffrey J; Pang, Yuanjie; Gordon, Reuven; Bokor, Jeffrey; Salmeron, Miquel B; Ogletree, D Frank; Ashby, Paul; Cabrini, Stefano; Schuck, P James

    2011-03-09

    We have demonstrated hyperspectral tip-enhanced Raman imaging on dielectric substrates using linearly polarized light and nanofabricated coaxial antenna tips. A full Raman spectrum was acquired at each pixel of a 256 by 256 pixel contact-mode atomic force microscope image of carbon nanotubes grown on a fused silica microscope coverslip, allowing D and G mode intensity and D-mode peak shifts to be measured with ∼20 nm spatial resolution. Tip enhancement was sufficient to acquire useful Raman spectra in 50-100 ms. Coaxial scan probes combine the efficiency and enhanced, ultralocalized optical fields of plasmonically coupled antennae with the superior topographical imaging properties of sharp metal tips. The yield of the coaxial tip fabrication process is close to 100%, and the tips are sufficiently durable to support hours of contact-mode force microscope imaging. Our coaxial probes avoid the limitations associated with the "gap-mode" imaging geometry used in most tip-enhanced Raman studies to date, where a sharp metal tip is held ∼1 nm above a metallic substrate with the sample located in the gap.

  5. Ultra-sound imaging for precision implantation of a multi sensor temperature probe in skeletal muscle tissue.

    PubMed

    Kenny, Glen P; Reardon, Frank D; Ducharme, Michel B; Reardon, Mark L; Zaleski, Wytek

    2002-10-01

    A technique for implanting multi sensor temperature probes in muscle tissue was developed to optimize the accuracy of the tissue temperature measurements and the internal localization of the probe. Real time ultra-sound imaging was used to (a) determine the best perpendicular insertion tract, (b) guide the insertion of the probe in order to avoid major blood vessels, and (c) verify the insertion point relative to discernable anatomic reference structures such as arteries and bone.

  6. 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

  7. 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

    2015-04-07

    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

  8. 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

  9. 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.

  10. 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.

  11. 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

  12. Clinical translation of an ultrasmall inorganic optical-PET imaging nanoparticle probe

    PubMed Central

    Phillips, Evan; Penate-Medina, Oula; Zanzonico, Pat B.; Carvajal, Richard D.; Mohan, Pauliah; Ye, Yunpeng; Humm, John; Gönen, Mithat; Kalaigian, Hovanes; Schöder, Heiko; Strauss, H. William; Larson, Steven M.; Wiesner, Ulrich; Bradbury, Michelle S.

    2015-01-01

    A first-in-human clinical trial of ultrasmall inorganic hybrid nanoparticles, “C dots” (Cornell dots), in patients with metastatic melanoma is described for the imaging of cancer. These renally excreted silica particles were labeled with 124I for positron emission tomography (PET) imaging and modified with cRGDY peptides for molecular targeting. 124I-cRGDY–PEG–C dot particles are inherently fluorescent, containing the dye, Cy5, so they may be used as hybrid PET-optical imaging agents for lesion detection, cancer staging, and treatment management in humans. However, the clinical translation of nanoparticle probes, including quantum dots, has not kept pace with the accelerated growth in minimally invasive surgical tools that rely on optical imaging agents. The safety, pharmacokinetics, clearance properties, and radiation dosimetry of 124I-cRGDY–PEG–C dots were assessed by serial PET and computerized tomography after intravenous administration in patients. Metabolic profiles and laboratory tests of blood and urine specimens, obtained before and after particle injection, were monitored over a 2-week interval. Findings are consistent with a well-tolerated inorganic particle tracer exhibiting in vivo stability and distinct, reproducible pharmacokinetic signatures defined by renal excretion. No toxic or adverse events attributable to the particles were observed. Coupled with preferential uptake and localization of the probe at sites of disease, these first-in-human results suggest safe use of these particles in human cancer diagnostics. PMID:25355699

  13. Photoacoustic Imaging with a Commercial Ultrasound System and a Custom Probe

    PubMed Central

    Wang, Xueding; Fowlkes, J. Brian; Cannata, Jonathan M.; Hu, Changhong; Carson, Paul L.

    2010-01-01

    Building photoacoustic imaging (PAI) systems by using stand-alone ultrasound (US) units makes it convenient to take advantage of the state-of-the-art ultrasonic technologies. However, the sometimes limited receiving sensitivity and the comparatively narrow bandwidth of commercial US probes may not be sufficient to acquire high quality photoacoustic images. In this work, a high-speed PAI system has been developed using a commercial US unit and a custom built 128-element piezoelectric-polymer array (PPA) probe using a P(VDF-TrFE) film and flexible circuit to define the elements. Since the US unit supports simultaneous signal acquisition from 64 parallel receive channels, PAI data for synthetic image formation from a 64 or 128 element array aperture can be acquired after a single or dual laser firing, respectively. Therefore, 2D B-scan imaging can be achieved with a maximum frame rate up to 10 Hz, limited only by the laser repetition rate. The uniquely properties of P(VDF-TrFE) facilitated a wide -6 dB receiving bandwidth of over 120 % for the array. A specially designed 128-channel preamplifier board made the connection between the array and the system cable which not only enabled element electrical impedance matching but also further elevated the signal-to-noise ratio (SNR) to further enhance the detection of weak photoacoustic signals. Through the experiments on phantoms and rabbit ears, the good performance of this PAI system was demonstrated. PMID:21276653

  14. Spectrally encoded fiber-based structured lighting probe for intraoperative 3D imaging

    PubMed Central

    Clancy, Neil T.; Stoyanov, Danail; Maier-Hein, Lena; Groch, Anja; Yang, Guang-Zhong; Elson, Daniel S.

    2011-01-01

    Three dimensional quantification of organ shape and structure during minimally invasive surgery (MIS) could enhance precision by allowing the registration of multi-modal or pre-operative image data (US/MRI/CT) with the live optical image. Structured illumination is one technique to obtain 3D information through the projection of a known pattern onto the tissue, although currently these systems tend to be used only for macroscopic imaging or open procedures rather than in endoscopy. To account for occlusions, where a projected feature may be hidden from view and/or confused with a neighboring point, a flexible multispectral structured illumination probe has been developed that labels each projected point with a specific wavelength using a supercontinuum laser. When imaged by a standard endoscope camera they can then be segmented using their RGB values, and their 3D coordinates calculated after camera calibration. The probe itself is sufficiently small (1.7 mm diameter) to allow it to be used in the biopsy channel of commonly used medical endoscopes. Surgical robots could therefore also employ this technology to solve navigation and visualization problems in MIS, and help to develop advanced surgical procedures such as natural orifice translumenal endoscopic surgery. PMID:22076272

  15. 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.

  16. Volumetric synthetic aperture imaging with a piezoelectric 2D row-column probe

    NASA Astrophysics Data System (ADS)

    Bouzari, Hamed; Engholm, Mathias; Christiansen, Thomas Lehrmann; Beers, Christopher; Lei, Anders; Stuart, Matthias Bo; Nikolov, Svetoslav Ivanov; Thomsen, Erik Vilain; Jensen, Jørgen Arendt

    2016-04-01

    The synthetic aperture (SA) technique can be used for achieving real-time volumetric ultrasound imaging using 2-D row-column addressed transducers. This paper investigates SA volumetric imaging performance of an in-house prototyped 3 MHz λ/2-pitch 62+62 element piezoelectric 2-D row-column addressed transducer array. Utilizing single element transmit events, a volume rate of 90 Hz down to 14 cm deep is achieved. Data are obtained using the experimental ultrasound scanner SARUS with a 70 MHz sampling frequency and beamformed using a delay-and-sum (DAS) approach. A signal-to-noise ratio of up to 32 dB is measured on the beamformed images of a tissue mimicking phantom with attenuation of 0.5 dB cm-1 MHz-1, from the surface of the probe to the penetration depth of 300λ. Measured lateral resolution as Full-Width-at-Half-Maximum (FWHM) is between 4λ and 10λ for 18% to 65% of the penetration depth from the surface of the probe. The averaged contrast is 13 dB for the same range. The imaging performance assessment results may represent a reference guide for possible applications of such an array in different medical fields.

  17. 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

  18. Kelvin probe force microscopy: imaging open-circuit voltage in optoelectronic devices

    NASA Astrophysics Data System (ADS)

    Tennyson, Elizabeth; Garrett, Joseph; Frantz, Jesse; Myers, Jason; Bekele, Robel; Sanghera, Jasbinder; Munday, Jeremy; Leite, Marina

    2015-03-01

    Scanning probe microscopy has been successfully implemented to probe the electrical characteristics of optoelectronic devices. Currently, a method that directly correlates measured signals to device performance is missing. We implement illuminated Kelvin probe force microscopy (KPFM) to spatially resolve the open-circuit voltage of optoelectronics with nanoscale resolution, 5 orders of magnitude better than previous methods. In illuminated-KPFM, the surface photovoltage, is the difference between the contact potential difference under illumination and in the dark, and proportional to the Fermi level splitting. We apply our imaging method to a variety of solar cells and find that the open-circuit voltage in some materials varies locally by >0.2 V, suggesting the spatial variation of non-radiative recombination strongly affects performance. A detailed examination of possible topography pick-up was excluded by measuring samples with modified surface morphology and considering the tip-sample separation dependence of the signal. This novel metrology enables new insights into the loss mechanisms that hinder solar cells and provides a new platform to image device performance with nanoscale resolution.

  19. 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.

  20. 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.

  1. 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

  2. The fine magnetic image of a high TC SQUID probe microscope

    NASA Astrophysics Data System (ADS)

    Hayashi, Tadayuki; Itozaki, Hideo

    2005-01-01

    We have developed a high TC SQUID probe microscope. A high permeability probe was used as a flux guide to improve its spatial resolution. The SQUID head with the flux guide makes it possible to measure samples with high spatial resolution in air at room temperature. The end of the flux guide and the SQUID were in vacuum with a 0.1 mm separation. The tip of the flux guide was in air. The rod diameter and length of the flux guide were 0.6 and 7 mm, respectively. The sharp tip of the flux guide required for high spatial resolution was prepared by microelectropolishing. Its tip radius was less than 1 µm. The static magnetic field pattern of magnetized toner particles was detected by this system and we obtained a high-resolution magnetic image with a spatial resolution of several microns.

  3. Highly selective "Off-On" fluorescent probe for histidine and its imaging in living cells.

    PubMed

    Chen, Tiantian; Yin, Liyan; Huang, Chusen; Qin, Yiqiao; Zhu, Weiping; Xu, Yufang; Qian, Xuhong

    2015-04-15

    A naphthalimide-based fluorescent probe CP has been synthesized with simple steps. It can selectively and sensitively recognize copper ions (Cu(2+)) in HEPES buffer (50mM, pH 7.2). The fluorescence intensity of CP is linearly proportional to the concentration of Cu(2+) ranging from 0-8.3μM (correlation coefficient R(2)=0.9808). The resulted complex CP@Cu can serve as a turn-on fluorescent probe for the detection of histidine and histidine rich proteins in broad pH application range. Upon the addition of histidine, the fluorescence intensity of CP@Cu exhibits a linear correlation with the concentration of histidine ranging from 0-200μM (correlation coefficient R(2)=0.9912). Moreover, CP@Cu has potential for imaging histidine in vitro experiments and has promise in real sample applications with great validity.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. Reconstruction of Kelvin probe force microscopy image with experimentally calibrated point spread function

    NASA Astrophysics Data System (ADS)

    Lan, Fei; Jiang, Minlin; Tao, Quan; Wei, Fanan; Li, Guangyong

    2017-03-01

    A Kelvin probe force microscopy (KPFM) image is sometimes difficult to interpret because it is a blurred representation of the true surface potential (SP) distribution of the materials under test. The reason for the blurring is that KPFM relies on the detection of electrostatic force, which is a long-range force compared to other surface forces. Usually, KPFM imaging model is described as the convolution of the true SP distribution of the sample with an intrinsic point spread function (PSF) of the measurement system. To restore the true SP signals from the blurred ones, the intrinsic PSF of the system is needed. In this work, we present a way to experimentally calibrate the PSF of the KPFM system. Taking the actual probe shape and experimental parameters into consideration, this calibration method leads to a more accurate PSF than the ones obtained from simulations. Moreover, a nonlinear reconstruction algorithm based on total variation (TV) regularization is applied to KPFM measurement to reverse the blurring caused by PSF during KPFM imaging process; as a result, noises are reduced and the fidelity of SP signals is improved.

  13. Imaging ac losses in superconducting films via scanning Hall probe microscopy

    NASA Astrophysics Data System (ADS)

    Dinner, Rafael B.; Moler, Kathryn A.; Feldmann, D. Matthew; Beasley, M. R.

    2007-04-01

    Various local probes have been applied to understanding current flow through superconducting films, which are often surprisingly inhomogeneous. Here, we show that magnetic imaging allows quantitative reconstruction of both current density J and electric field E resolved in time and space in a film carrying subcritical ac current. Current reconstruction entails inversion of the Biot-Savart law, while electric fields are reconstructed using Faraday’s law. We describe the corresponding numerical procedures, largely adapting existing work to the case of a strip carrying ac current, but including other methods of obtaining the complete electric field from the inductive portion determined by Faraday’s law. We also delineate the physical requirements behind the mathematical transformations. We then apply the procedures to images of a strip of YBa2Cu3O7-δ carrying an ac current at 400Hz . Our scanning Hall probe microscope produces a time series of magnetic images of the strip with 1μm spatial resolution and 25μs time resolution. Combining the reconstructed J and E , we obtain a complete characterization including local critical current density, E-J curves, and power losses. This analysis has a range of applications from fundamental studies of vortex dynamics to practical coated conductor development.

  14. 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

  15. [Development of near-infrared fluorescent probes for in-vivo imaging].

    PubMed

    Kojima, Hirotatsu

    2008-11-01

    The number of reports on new techniques in molecular imaging has been recently increasing because of their usefulness in biological, medical, and clinical research. Fluorescence imaging methods are generally superior in terms of sensitivity, selectivity and ease of use. Cyanine dyes have been employed as fluorescent labels in fluorescence imaging studies of biological mechanisms. In particular, tricarbocyanines have the advantage that light at their emission and absorption maxima in the near-infrared (NIR) region around 650-900 nm is relatively poorly absorbed by biomolecules, and so can penetrate deeply into tissues. There is also less autofluorescence in this region. In addition to cyanine dyes for straightforward fluorescence labeling, we successfully developed cyanine dyes whose fluorescence intensity changes upon specific reaction with nitric oxide, which is an important signaling molecule involved in the regulation of a wide range of physiological and pathophysiological mechanisms, and many disorders. Then, we synthesized dipicolylcyanine (DIPCY), consisting of tricarbocyanine as a fluorophore and dipicolylethylenediamine as a heavy metal chelator, and investigated its response to various heavy metal ions. Upon addition of zinc ion, a red shift of the absorbance maximum was observed. Namely, DIPCY can work as a ratiometric fluorescent sensor for zinc ion in the NIR region. Moreover, we have recently developed several pH probes based on the amine-substituted tricarbocyanine fluorophore. We could measure pH with these fluorescent probes by a ratiometric monitoring method.

  16. 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.

  17. 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.

  18. Fluorescence encoded super resolution imaging based on a location estimation algorithm for high-density fluorescence probes

    NASA Astrophysics Data System (ADS)

    Nishimura, Takahiro; Kimura, Hitoshi; Ogura, Yusuke; Tanida, Jun

    2016-11-01

    In this paper, we propose a fluorescence encoded super resolution technique based on an estimation algorithm to determine locations of high-density fluorescence emitters. In our method, several types of fluorescence coded probes are employed to reduce densities of target molecules labeled with individual codes. By applying an estimation algorithm to each coded image, the locations of the high density probes can be determined. Due to multiplexed fluorescence imaging, this approach will provide fast super resolution microscopy. In experiments, we evaluated the performance of the method using probes with different fluorescence wavelengths. Numerical simulation results show that the locations of probes with the density of 200 μ m^{-2} , which is a typical membrane-receptor expression level, are determined with acquisition of 16 different coded images.

  19. Introduction: feature issue on optical molecular probes, imaging, and drug delivery.

    PubMed

    Campagnola, Paul; French, Paul M W; Georgakoudi, Irene; Mycek, Mary-Ann

    2014-02-01

    The editors introduce the Biomedical Optics Express feature issue "Optical Molecular Probes, Imaging, and Drug Delivery," which is associated with a Topical Meeting of the same name held at the 2013 Optical Society of America (OSA) Optics in the Life Sciences Congress in Waikoloa Beach, Hawaii, April 14-18, 2013. The international meeting focused on the convergence of optical physics, photonics technology, nanoscience, and photochemistry with drug discovery and clinical medicine. Papers in this feature issue are representative of meeting topics, including advances in microscopy, nanotechnology, and optics in cancer research.

  20. Library Synthesis, Screening, and Discovery of Modified Zinc(II)-Bis(dipicolylamine) Probe for Enhanced Molecular Imaging of Cell Death

    PubMed Central

    2015-01-01

    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. PMID:24575875

  1. Mn-doped near-infrared quantum dots as multimodal targeted probes for pancreatic cancer imaging

    NASA Astrophysics Data System (ADS)

    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.

  2. Emerging Roles of the Endolumenal Functional Lumen Imaging Probe in Gastrointestinal Motility Disorders

    PubMed Central

    Ata-Lawenko, Rona M; Lee, Yeong Yeh

    2017-01-01

    Gastrointestinal sphincters play a vital role in gut function and motility by separating the gut into functional segments. Traditionally, function of sphincters including the esophagogastric junction is studied using endoscopy and manometry. However, due to its dynamic biomechanical properties, data on distensibility and compliance may provide a more accurate representation of the sphincter function. The endolumenal functional lumen imaging probe (EndoFLIP) system uses a multi-detector impedance planimetry system to provide data on tissue distensibility and geometric changes in the sphincter as measured through resistance to volumetric distention with real-time images. With the advent of EndoFLIP studies, esophagogastric junction dysfunction and other disorders of the stomach and bowels may be better evaluated. It may be utilized as a tool in predicting effectiveness of endoscopic and surgical treatments as well as patient outcomes. PMID:28013295

  3. 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.

  4. MRT letter: An extended scanning probe microscopy system for macroscopic topography imaging.

    PubMed

    Fu, Ji; Li, Faxin

    2014-10-01

    Enlightened by the principle of scanning probe microscopy or atomic force microscope (AFM), we proposed a novel surface topography imaging system based on the scanning of a piezoelectric unimorph cantilever. The height of sample surface can be obtained by recording the cantilever's strain using an ultra-sensitive strain gauge and the Z-axis movement is realized by electric bending of the cantilever. This system can be operated in the way similar to the contact mode in AFM, with the practical height detection resolution better than 100 nm. Imaging of the inner surface of a steel tube and on a transparent wing of a honey bee were conducted and the obtained results showed that this proposed system is a very promising solution for in situ topography mapping.

  5. 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

  6. 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

  7. [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

  8. [18F]CFA as a clinically translatable probe for PET imaging of deoxycytidine kinase activity.

    PubMed

    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

    2016-04-12

    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-[(18)F]Clofarabine; 2-chloro-2'-deoxy-2'-[(18)F]fluoro-9-β-d-arabinofuranosyl-adenine ([(18)F]CFA) and 2'-deoxy-2'-[(18)F]fluoro-9-β-d-arabinofuranosyl-guanine ([(18)F]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, [(18)F]CFA is primarily a substrate for dCK, with minimal cross-reactivity. In contrast, [(18)F]F-AraG is a better substrate for dGK than for dCK. [(18)F]CFA accumulation in leukemia cells correlated with dCK expression and was abrogated by treatment with a dCK inhibitor. Although [(18)F]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 [(18)F]CFA, leading to increased dCK-dependent probe accumulation. First-in-human, to our knowledge, [(18)F]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 [(18)F]CFA for dCK and its favorable biodistribution in humans justify further studies to validate [(18)F]CFA PET as a new cancer biomarker for treatment stratification and monitoring.

  9. Probing for Exoplanets Hiding in Dusty Debris Disks: Inner (<10 AU) Disk Imaging, Characterization, and Exploration

    NASA Astrophysics Data System (ADS)

    Schneider, Glenn; HST GO 12228 Team

    2011-01-01

    We are obtaining HST/STIS observations of a well-selected sample of eleven circumstellar (CS) debris disks, all with HST pedigree, using PSF-subtracted multi-roll coronagraphic imaging. Our observations are probing the interior CS regions of these debris systems (inner working distances < approximately 8 AU for half the sample), corresponding to the giant planet and Kuiper belt regions within our own solar system. These images will enable us to: (a) directly inter-compare the architectures of these exoplanetary debris systems in the context of our own Solar System, (b) characterize the material in these regions at high spatial resolution and, (c) look for sub-structures within the disks that are sign posts of planetary formation and evolution; in particular, asymmetries and non-uniform debris structures signaling the presence of co-orbiting perturbing planets. All of our objects were previously observed at longer wavelengths (with lower spatial resolution and imaging efficacy) with NICMOS, but with an inner working angle comparable to STIS multi-roll coronagraphy. The combination of new optical and existing near-IR imaging will strongly constrain the dust properties enabling an assessment of grain processing and planetesimal populations. These results will directly inform upon the posited planet formation mechanisms that occur after the approximately 10 My epoch of gas depletion (a time in our solar system when giant planets were migrating and the terrestrial planets were forming) and directly test theoretical models of these processes. The outer reaches (only) of most of these systems were previously observed with a much larger ( 6x on average), spatially limiting, effective inner working angle of the ACS coronagraph and do not reveal the inner structures of these CS disks. Our investigation will uniquely probe into the interior regions of these systems for the first time with spatial resolution comparable to ACS and with augmenting NICMOS near-IR disk photometry

  10. Ultrahigh relaxivity and safe probes of manganese oxide nanoparticles for in vivo imaging

    PubMed Central

    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.

    2013-01-01

    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. PMID:24305731

  11. 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

  12. 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.

  13. 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.

  14. Photophysics of Fluorescence Probes for Single Molecule Biophysics and Super-Resolution Imaging

    PubMed Central

    Ha, Taekjip; Tinnefeld, Philip

    2013-01-01

    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 certain color and brightness but instead have their own ‘personalities’ regarding spectroscopic parameters, redox properties, size and water solubility, photostability and several more. 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 which was later overcome using Trolox through reducing/oxidizing system, but a boon for super-resolution imaging due to the controllable photoswitching. Understanding photophysics is critical in design and interpreting single molecule experiments. PMID:22404588

  15. 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

  16. Optimized multimodal functional magnetic resonance imaging/near-infrared spectroscopy probe for ultrahigh-resolution mapping

    PubMed Central

    Hocke, Lia Maria; Cayetano, Kenroy; Tong, Yunjie; Frederick, Blaise

    2015-01-01

    Abstract. Functional near-infrared spectroscopy (fNIRS) is an increasingly important noninvasive method in neuroscience due to its high temporal resolution and ability to independently measure oxy- and deoxy-hemoglobin. However, the relatively low spatial resolution of fNIRS makes it difficult to relate this signal to underlying anatomy. Simultaneous functional magnetic resonance imaging (fMRI) can complement fNIRS with superior spatial resolution and the ability to image the entire brain, providing additional information to improve fNIRS localization. However, current simultaneous fMRI/fNIRS acquisition methods are not optimal, due to the poor physical compatibility of existing MR coils and fNIRS optodes. Here, we present a technique to manufacture a true multimodal fMRI/fNIRS probe in which both modalities can be used with maximal sensitivity. To achieve this, we designed custom MR coils with integral fNIRS optodes using three-dimensional printing. This multimodal probe can be used to optimize spatial (1.2×1.2×1.8  mm) and temporal resolution (2.5 Hz) of fMRI, and it provides maximal MRI sensitivity, while allowing for high flexibility in the location and density of fNIRS optodes within the area of interest. Phantom and human data are shown to confirm the improvement in sensitivity in both modalities. This probe shows promise for addressing fundamental questions of the relation of fNIRS to physiology. PMID:26668816

  17. The Scanning Mass Spectrometry Probe: A Scanning Probe Electrospray Ion Source for Imaging Mass Spectrometry of Submerged Interfaces and Transient Events in Solution

    PubMed Central

    Kottke, Peter A.; Degertekin, F. Levent; Fedorov, Andrei G.

    2009-01-01

    The scanning mass spectrometry (SMS) probe is new electrospray ion source. Motivated by the need for untargeted chemical imaging of dynamic events in solution, we have exploited an approach to electrospray ionization (ESI) that allows continuous sampling from a highly localized volume (~picoliters) in a liquid environment, softly ionizes molecules in the sample to render them amenable for mass spectrometric analysis, and sends the ions to the mass spectrometer. The key underlying concepts for our approach are1)Treating the electrospray capillary inlet as a chemical scanning probe, and2)Locating the electrospray point as close as possible to the sampling point, thus providing the shortest response time possible. This approach enables chemical monitoring or imaging of submerged interfaces, providing access to details of spatial heterogeneity and temporal changes within liquid samples. It also permits direct access to liquid/ liquid interfaces for ESI-MS analysis. In this Letter we report the first demonstrations of these capabilities of the SMS probe, and describe some of the probe's basic characteristics. PMID:19904914

  18. 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

  19. 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.

  20. Long-circulating iodinated albumin-gadolinium nanoparticles as enhanced magnetic resonance and computed tomography imaging probes for osteosarcoma visualization.

    PubMed

    Wang, Qianliang; Lv, Ling; Ling, Zhuoyan; Wang, Yangyun; Liu, Yujing; Li, Liubing; Liu, Guodong; Shen, Liqin; Yan, Jun; Wang, Yong

    2015-04-21

    Multimodal imaging probes represent an extraordinary tool for accurate diagnosis of diseases due to the complementary advantages of multiple imaging modalities. The purpose of the work was to fabricate a simple dual-modality MR/CT probe for osteosarcoma visualization in vivo. Protein-directed synthesis methods offer a suitable alternative to MR/CT probe produced by synthetic chemistry. Bovine serum albumin (BSA) bound to gadolinium nanoparticles (GdNPs) was first prepared via a biomimetic synthesis method and was subsequently iodinated by chloramine-T method. The final iodinated BSA-GdNPs (I-BSA-GdNPs) showed excellent chemical stability and biocompatibility, intense X-ray attenuation coefficient, and good MR imaging ability. However, an iodinated protein nanoparticles synthesis for MR/CT imaging, as well as its useful application, has not been reported yet. Intravenous injection of I-BSA-GdNPs into orthotopic osteosarcoma-bearing rats led to its accumulation and retention by the tumor, allowing for a noninvasive tumor dual-modality imaging through the intact thigh. The long-circulating dual-model I-BSA-GdNPs probes possess potential application for image-guided drug delivery and image-guided surgery. Our study is therefore highlighting the properties of albumin in this field combined with its useful use in dual-model MR/CT osteosarcoma visualization, underlining its potential use as a drug carrier for a future therapy on cancer.

  1. Flexible, high-resolution micro-optical coherence tomography endobronchial probe toward in vivo imaging of cilia.

    PubMed

    Cui, Dongyao; Chu, Kengyeh K; Yin, Biwei; Ford, Timothy N; Hyun, Chulho; Leung, Hui Min; Gardecki, Joseph A; Solomon, George M; Birket, Susan E; Liu, Linbo; Rowe, Steven M; Tearney, Guillermo J

    2017-02-15

    We report the design and fabrication of a flexible, longitudinally scanning high-resolution micro-optical coherence tomography (μOCT) endobronchial probe, optimized for micro-anatomical imaging in airways. The 2.4 mm diameter and flexibility of the probe allows it to be inserted into the instrument channel of a standard bronchoscope, enabling real-time video guidance of probe placement. To generate a depth-of-focus enhancing annular beam, we utilized a new fabrication method, whereby a hollow glass ferrule was angle-polished and gold-coated to produce an elongated annular reflector. We present validation data that verifies the preservation of linear scanning, despite the use of flexible materials. When utilized on excised, cultured mouse trachea, the probe acquired images of comparable quality to those obtained by a benchtop μOCT system.

  2. Directional Histogram Ratio at Random Probes: A Local Thresholding Criterion for Capillary Images

    PubMed Central

    Lu, Na; Silva, Jharon; Gu, Yu; Gerber, Scott; Wu, Hulin; Gelbard, Harris; Dewhurst, Stephen; Miao, Hongyu

    2013-01-01

    With the development of micron-scale imaging techniques, capillaries can be conveniently visualized using methods such as two-photon and whole mount microscopy. However, the presence of background staining, leaky vessels and the diffusion of small fluorescent molecules can lead to significant complexity in image analysis and loss of information necessary to accurately quantify vascular metrics. One solution to this problem is the development of accurate thresholding algorithms that reliably distinguish blood vessels from surrounding tissue. Although various thresholding algorithms have been proposed, our results suggest that without appropriate pre- or post-processing, the existing approaches may fail to obtain satisfactory results for capillary images that include areas of contamination. In this study, we propose a novel local thresholding algorithm, called directional histogram ratio at random probes (DHR-RP). This method explicitly considers the geometric features of tube-like objects in conducting image binarization, and has a reliable performance in distinguishing small vessels from either clean or contaminated background. Experimental and simulation studies suggest that our DHR-RP algorithm is superior over existing thresholding methods. PMID:23525856

  3. 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

  4. 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.

  5. Stability limits and defect dynamics in Ag nanoparticles probed by Bragg coherent diffractive imaging

    DOE PAGES

    Liu, Y.; Lopes, P. P.; Cha, W.; ...

    2017-02-10

    Dissolution is critical to nanomaterial stability, especially for partially dealloyed nanoparticle catalysts. Unfortunately, highly active catalysts are often not stable in their reactive environments, preventing widespread application. Thus, focusing on the structure–stability relationship at the nanoscale is crucial and will likely play an important role in meeting grand challenges. Recent advances in imaging capability have come from electron, X-ray, and other techniques but tend to be limited to specific sample environments and/or two-dimensional images. Here, we report investigations into the defect-stability relationship of silver nanoparticles to voltage-induced electrochemical dissolution imaged in situ in three dimensional detail by Bragg coherent diffractivemore » imaging. We first determine the average dissolution kinetics by stationary probe rotating disk electrode in combination with inductively coupled plasma mass spectrometry, which allows in situ measurement of Ag+ ion formation. We then observe the dissolution and redeposition processes in single nanocrystals, providing unique insight about the role of surface strain, defects, and their coupling to the dissolution chemistry. Finally, the methods developed and the knowledge gained go well beyond a “simple” silver electrochemistry and are applicable to all electrocatalytic reactions where functional links between activity and stability are controlled by structure and defect dynamics.« less

  6. First Results from the Descent Imager/Spectral Radiometer (DISR) Experiment on the Huygens Entry Probe of Titan

    NASA Technical Reports Server (NTRS)

    Tomasko, M. G.; Doose, L. R.; Rizk, B.; Smith, P.; See, C.; Bushroe, M.; McFarlane, L.; Engel, S.; Eibl, A.; Karkoschka, E.

    2005-01-01

    The Cassini-Huygens mission was launched on October 15, 1997, and arrived in Orbit around Saturn in July, 2004. The Huygens Probe was released from the Cassini Orbiter on December 24, 2004 and entered Titan s atmosphere on January 14, 2005. Here we give the first results from the Descent Imager/Spectral Radiometer (DISR) instrument aboard the Huygens Probe during its descent into the atmosphere of Titan. Measurements were made by several different optical systems and sensors.

  7. Probing for Exoplanets Hiding in Dusty Debris Disks: Inner {<10 AU} Disk Imaging, Characterization, and Exploration

    NASA Astrophysics Data System (ADS)

    Schneider, Glenn

    2010-09-01

    We propose new visible-light observations of a well-selected sample of circumstellar {CS} debris disks, all with HST pedigree, using STIS PSF-subtracted multi-roll coronagraphic imaging. Our new observations will probe the interior CS regions of these debris systems {with inner working distances of < approximately 8 AU for half the stars in this sample}, corresponding to the giant planet and Kuiper belt regions within our own solar system. These new images will enable us to directly inter-compare the architectures of these exoplanetary debris systems in the context of our own Solar System. These observations will also permit us, for the first time, to characterize the material in these regions at high spatial resolution and to look for sub-structures within the disks that are the sign posts of planetary formation and evolution; in particular, asymmetries and non-uniform debris structures signal the presence of co-orbiting perturbing planets. Additionally, all of our objects have been observed previously at longer wavelengths {but much lower spatial resolution and imaging efficacy} with NICMOS, but with an inner working angle comparable to STIS multi-roll coronagraphy. The combination of new optical and existing near-IR imaging will strongly constrain the dust properties, thus enabling an assessment of grain processing and planetesimal populations. These results will directly inform upon the posited planet formation mechanisms that occur after the 10 My epoch of gas depletion, at a time in our solar system when giant planets were migrating and the terrestrial planets were forming, and directly test theoretical models of these processes. The outer reaches {only} of most of these systems were previously observed with a much larger { 6x on average}, spatially limiting, effective inner working angle of the ACS coronagraph. The previous ACS images are therefore completely inadequate to address our science goals of imaging the inner structures of these CS disks. Our

  8. Superior sensitivity of novel molecular imaging probe: simultaneously targeting two types of endothelial injury markers

    PubMed Central

    Sun, Dawei; Nakao, Shintaro; Xie, Fang; Zandi, Souska; Schering, Alexander; Hafezi-Moghadam, Ali

    2010-01-01

    The need remains great for early diagnosis of diseases. The special structure of the eye provides a unique opportunity for noninvasive light-based imaging of fundus vasculature. To detect endothelial injury at the early and reversible stage of adhesion molecule up-regulation, we generated novel imaging agents that target two distinct types of endothelial molecules, a mediator of rolling, P-selectin, and one that mediates firm adhesion, ICAM-1. Interactions of these double-conjugated fluorescent microspheres (MSs) in retinal or choroidal microvasculature were visualized in live animals by scanning laser ophthalmoscopy. The new imaging agents showed significantly higher sensitivity for detection of endothelial injury than singly conjugated MSs (rPSGL-1- or α-ICAM-1-conjugated), both in terms of rolling (P<0.01) and firm adhesion (P<0.01). The rolling flux of α-ICAM-1-conjugated MSs did not differ in EIU animals, whereas double-conjugated MSs showed significantly higher rolling flux (P<0.01), revealing that ICAM-1 in vivo supports rolling, once MS interaction with the endothelium is initiated. Double-conjugated MSs specifically detected firmly adhering leukocytes (P<0.01), allowing in vivo quantification of immune response. Antiinflammatory treatment with dexamethasone led to reduced leukocyte accumulation (P<0.01) as well as MS interaction (P<0.01), which suggests that treatment success and resolution of inflammation is quantitatively reflected with this molecular imaging approach. This work introduces novel imaging agents for noninvasive detection of endothelial injury in vivo. Our approach may be developed further to diagnose human disease at a much earlier stage than currently possible.—Sun, D., Nakao, S., Xie, F., Zandi, S., Schering, A., Hafezi-Moghadam, A. Superior sensitivity of novel molecular imaging probe: simultaneously targeting two types of endothelial injury markers. PMID:20103715

  9. Transoral carotid ultrasonography using a micro convex probe with B-flow imaging for extracranial internal carotid artery dissection.

    PubMed

    Sakima, Hirokuni; Isa, Katsunori; Anegawa, Takahiro; Kokuba, Kazuhito; Nakachi, Koh; Goya, Yoshino; Tokashiki, Takashi; Ishiuchi, Shogo; Ohya, Yusuke

    2012-11-01

    We report on transoral carotid ultrasonography using a micro convex probe with B-flow imaging for determining spontaneous extracranial internal carotid artery dissection just below the petrous portion. A 49-year-old man suffered cortical and subcortical infarction in the region of the right middle cerebral artery. Magnetic resonance angiography on the third day of admission revealed spontaneous recanalization of the right internal carotid artery associated with an intimal flap-like structure at the petrous portion. Transoral carotid ultrasonography using a micro convex probe revealed right extracranial internal carotid artery dissection, showing an increased diameter of the right extracranial internal carotid artery with double lumen formation, stenosis of the true lumen, and a mobile intimal flap in B-flow imaging. Transoral carotid ultrasonography using a micro convex probe was helpful to attempt a self-expanding stent for recanalizing right extracranial internal carotid artery dissection. The patient recovered and was discharged ambulatory. The size of the micro convex probe was optimum for transoral carotid ultrasonography in our patient. Micro convex probe is more commonly used than the standard transoral carotid ultrasonography probe, which lacks versatility. We consider that transoral carotid ultrasonography using a micro convex probe could be routinely used for ultrasonographic evaluation of extracranial internal carotid artery dissection.

  10. 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.

  11. Piezoelectric tuning fork probe for atomic force microscopy imaging and specific recognition force spectroscopy of an enzyme and its ligand.

    PubMed

    Makky, Ali; Viel, Pascal; Chen, Shu-wen Wendy; Berthelot, Thomas; Pellequer, Jean-Luc; Polesel-Maris, Jérôme

    2013-11-01

    Piezoelectric quartz tuning fork has drawn the attention of many researchers for the development of new atomic force microscopy (AFM) self-sensing probes. However, only few works have been done for soft biological materials imaging in air or aqueous conditions. The aim of this work was to demonstrate the efficiency of the AFM tuning fork probe to perform high-resolution imaging of proteins and to study the specific interaction between a ligand and its receptor in aqueous media. Thus, a new kind of self-sensing AFM sensor was introduced to realize imaging and biochemical specific recognition spectroscopy of glucose oxidase enzyme using a new chemical functionalization procedure of the metallic tips based on the electrochemical reduction of diazonium salt. This scanning probe as well as the functionalization strategy proved to be efficient respectively for the topography and force spectroscopy of soft biological materials in buffer conditions.

  12. A mouse-human phase 1 co-clinical trial of a protease-activated fluorescent probe for imaging cancer

    PubMed Central

    Whitley, Melodi Javid; Cardona, Diana M.; Lazarides, Alexander L.; Spasojevic, Ivan; Ferrer, Jorge M.; Cahill, Joan; Lee, Chang-Lung; Snuderl, Matija; Blazer, Dan G.; Hwang, E. Shelley; Greenup, Rachel A.; Mosca, Paul J.; Mito, Jeffrey K.; Cuneo, Kyle C.; Larrier, Nicole A.; O’Reilly, Erin K.; Riedel, Richard F.; Eward, William C.; Strasfeld, David B.; Fukumura, Dai; Jain, Rakesh K.; Lee, W. David; Griffith, Linda G.; Bawendi, Moungi G.; Kirsch, David G.; Brigman, Brian E.

    2016-01-01

    Local recurrence is a common cause of treatment failure for patients with solid tumors. Intraoperative detection of microscopic residual cancer in the tumor bed could be used to decrease the risk of a positive surgical margin, reduce rates of reexcision, and tailor adjuvant therapy. We used a protease-activated fluorescent imaging probe, LUM015, to detect cancer in vivo in a mouse model of soft tissue sarcoma (STS) and ex vivo in a first-in-human phase 1 clinical trial. In mice, intravenous injection of LUM015 labeled tumor cells, and residual fluorescence within the tumor bed predicted local recurrence. In 15 patients with STS or breast cancer, intravenous injection of LUM015 before surgery was well tolerated. Imaging of resected human tissues showed that fluorescence from tumor was significantly higher than fluorescence from normal tissues. LUM015 biodistribution, pharmacokinetic profiles, and metabolism were similar in mouse and human subjects. Tissue concentrations of LUM015 and its metabolites, including fluorescently labeled lysine, demonstrated that LUM015 is selectively distributed to tumors where it is activated by proteases. Experiments in mice with a constitutively active PEGylated fluorescent imaging probe support a model where tumor-selective probe distribution is a determinant of increased fluorescence in cancer. These co-clinical studies suggest that the tumor specificity of protease-activated imaging probes, such as LUM015, is dependent on both biodistribution and enzyme activity. Our first-in-human data support future clinical trials of LUM015 and other protease-sensitive probes. PMID:26738797

  13. A mouse-human phase 1 co-clinical trial of a protease-activated fluorescent probe for imaging cancer.

    PubMed

    Whitley, Melodi Javid; Cardona, Diana M; Lazarides, Alexander L; Spasojevic, Ivan; Ferrer, Jorge M; Cahill, Joan; Lee, Chang-Lung; Snuderl, Matija; Blazer, Dan G; Hwang, E Shelley; Greenup, Rachel A; Mosca, Paul J; Mito, Jeffrey K; Cuneo, Kyle C; Larrier, Nicole A; O'Reilly, Erin K; Riedel, Richard F; Eward, William C; Strasfeld, David B; Fukumura, Dai; Jain, Rakesh K; Lee, W David; Griffith, Linda G; Bawendi, Moungi G; Kirsch, David G; Brigman, Brian E

    2016-01-06

    Local recurrence is a common cause of treatment failure for patients with solid tumors. Intraoperative detection of microscopic residual cancer in the tumor bed could be used to decrease the risk of a positive surgical margin, reduce rates of reexcision, and tailor adjuvant therapy. We used a protease-activated fluorescent imaging probe, LUM015, to detect cancer in vivo in a mouse model of soft tissue sarcoma (STS) and ex vivo in a first-in-human phase 1 clinical trial. In mice, intravenous injection of LUM015 labeled tumor cells, and residual fluorescence within the tumor bed predicted local recurrence. In 15 patients with STS or breast cancer, intravenous injection of LUM015 before surgery was well tolerated. Imaging of resected human tissues showed that fluorescence from tumor was significantly higher than fluorescence from normal tissues. LUM015 biodistribution, pharmacokinetic profiles, and metabolism were similar in mouse and human subjects. Tissue concentrations of LUM015 and its metabolites, including fluorescently labeled lysine, demonstrated that LUM015 is selectively distributed to tumors where it is activated by proteases. Experiments in mice with a constitutively active PEGylated fluorescent imaging probe support a model where tumor-selective probe distribution is a determinant of increased fluorescence in cancer. These co-clinical studies suggest that the tumor specificity of protease-activated imaging probes, such as LUM015, is dependent on both biodistribution and enzyme activity. Our first-in-human data support future clinical trials of LUM015 and other protease-sensitive probes.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. Thermal ion imagers and Langmuir probes in the Swarm electric field instruments

    NASA Astrophysics Data System (ADS)

    Knudsen, D. J.; Burchill, J. K.; Buchert, S. C.; Eriksson, A. I.; Gill, R.; Wahlund, J.-E.; Åhlen, L.; Smith, M.; Moffat, B.

    2017-02-01

    The European Space Agency's three Swarm satellites were launched on 22 November 2013 into nearly polar, circular orbits, eventually reaching altitudes of 460 km (Swarm A and C) and 510 km (Swarm B). Swarm's multiyear mission is to make precision, multipoint measurements of low-frequency magnetic and electric fields in Earth's ionosphere for the purpose of characterizing magnetic fields generated both inside and external to the Earth, along with the electric fields and other plasma parameters associated with electric current systems in the ionosphere and magnetosphere. Electric fields perpendicular to the magnetic field B→ are determined through ion drift velocity v→i and magnetic field measurements via the relation E→⊥=-v→i×B→. Ion drift is derived from two-dimensional images of low-energy ion distribution functions provided by two Thermal Ion Imager (TII) sensors viewing in the horizontal and vertical planes; v→i is corrected for spacecraft potential as determined by two Langmuir probes (LPs) which also measure plasma density ne and electron temperature Te. The TII sensors use a microchannel-plate-intensified phosphor screen imaged by a charge-coupled device to generate high-resolution distribution images (66 × 40 pixels) at a rate of 16 s-1. Images are partially processed on board and further on the ground to generate calibrated data products at a rate of 2 s-1; these include v→i, E→⊥, and ion temperature Ti in addition to electron temperature Te and plasma density ne from the LPs.

  19. Multimodal imaging probes based on Gd-DOTA conjugated quantum dot nanomicelles.

    PubMed

    Liu, Liwei; Law, Wing-Cheung; Yong, Ken-Tye; Roy, Indrajit; Ding, Hong; Erogbogbo, Folarin; Zhang, Xihe; Prasad, Paras N

    2011-05-07

    Recently, multimodal nanoparticles integrating dual- or tri-imaging modalities into a single hybrid nanosystem have attracted plenty of attention in biomedical research. Here, we report the fabrication of two types of multimodal micelle-encapsulated nanoparticles, which were systematically characterized and thoroughly evaluated in terms of their imaging potential and biocompatibility. Optical and magnetic resonance (MR) imaging probes were integrated by conjugating DOTA-gadolinium (Gd) derivative to quantum dot based nanomicelles. Two amphiphilic block copolymer micelles, amine-terminated mPEG-phospholipid and amine-modified Pluronic F127, were chosen as the capping agents because of their excellent biocompatibility and ability to prevent opsonization and prolong circulation time in vivo. Owing to their different hydrophobic-hydrophilic structure, the micellar aggregates exhibited different sizes and protection of core QDs. This work revealed the differences between these nanomicelles in terms of the stability over a wide range of pH, along with their cytotoxicity and the capacity for chelating gadolinium, thus providing a useful guideline for tailor-making multimodal nanoparticles for specific biomedical applications.

  20. 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

  1. Near-field terahertz probes with room-temperature nanodetectors for subwavelength resolution imaging

    PubMed Central

    Mitrofanov, Oleg; Viti, Leonardo; Dardanis, Enrico; Giordano, Maria Caterina; Ercolani, Daniele; Politano, Antonio; Sorba, Lucia; Vitiello, Miriam S.

    2017-01-01

    Near-field imaging with terahertz (THz) waves is emerging as a powerful technique for fundamental research in photonics and across physical and life sciences. Spatial resolution beyond the diffraction limit can be achieved by collecting THz waves from an object through a small aperture placed in the near-field. However, light transmission through a sub-wavelength size aperture is fundamentally limited by the wave nature of light. Here, we conceive a novel architecture that exploits inherently strong evanescent THz field arising within the aperture to mitigate the problem of vanishing transmission. The sub-wavelength aperture is originally coupled to asymmetric electrodes, which activate the thermo-electric THz detection mechanism in a transistor channel made of flakes of black-phosphorus or InAs nanowires. The proposed novel THz near-field probes enable room-temperature sub-wavelength resolution coherent imaging with a 3.4 THz quantum cascade laser, paving the way to compact and versatile THz imaging systems and promising to bridge the gap in spatial resolution from the nanoscale to the diffraction limit. PMID:28287123

  2. 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

  3. Near-field terahertz probes with room-temperature nanodetectors for subwavelength resolution imaging

    NASA Astrophysics Data System (ADS)

    Mitrofanov, Oleg; Viti, Leonardo; Dardanis, Enrico; Giordano, Maria Caterina; Ercolani, Daniele; Politano, Antonio; Sorba, Lucia; Vitiello, Miriam S.

    2017-03-01

    Near-field imaging with terahertz (THz) waves is emerging as a powerful technique for fundamental research in photonics and across physical and life sciences. Spatial resolution beyond the diffraction limit can be achieved by collecting THz waves from an object through a small aperture placed in the near-field. However, light transmission through a sub-wavelength size aperture is fundamentally limited by the wave nature of light. Here, we conceive a novel architecture that exploits inherently strong evanescent THz field arising within the aperture to mitigate the problem of vanishing transmission. The sub-wavelength aperture is originally coupled to asymmetric electrodes, which activate the thermo-electric THz detection mechanism in a transistor channel made of flakes of black-phosphorus or InAs nanowires. The proposed novel THz near-field probes enable room-temperature sub-wavelength resolution coherent imaging with a 3.4 THz quantum cascade laser, paving the way to compact and versatile THz imaging systems and promising to bridge the gap in spatial resolution from the nanoscale to the diffraction limit.

  4. 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.

  5. 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.

  6. Molecular Platform for Design and Synthesis of Targeted Dual-Modality Imaging Probes

    PubMed Central

    2015-01-01

    We report a versatile dendritic structure based platform for construction of targeted dual-modality imaging probes. The platform contains multiple copies of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) branching out from a 1,4,7-triazacyclononane-N,N′,N″-triacetic acid (NOTA) core. The specific coordination chemistries of the NOTA and DOTA moieties offer specific loading of 68/67Ga3+ and Gd3+, respectively, into a common molecular scaffold. The platform also contains three amino groups which can potentiate targeted dual-modality imaging of PET/MRI or SPECT/MRI (PET: positron emission tomography; SPECT: single photon emission computed tomography; MRI: magnetic resonance imaging) when further functionalized by targeting vectors of interest. To validate this design concept, a bimetallic complex was synthesized with six peripheral Gd-DOTA units and one Ga-NOTA core at the center, whose ion T1 relaxivity per gadolinium atom was measured to be 15.99 mM–1 s–1 at 20 MHz. Further, the bimetallic agent demonstrated its anticipated in vivo stability, tissue distribution, and pharmacokinetic profile when labeled with 67Ga. When conjugated with a model targeting peptide sequence, the trivalent construct was able to visualize tumors in a mouse xenograft model by both PET and MRI via a single dose injection. PMID:25615011

  7. 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

  8. 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

    2016-03-02

    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.

  9. 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.

  10. 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.

  11. Quantum dots-based probes conjugated to Annexin V for photostable apoptosis detection and imaging

    NASA Astrophysics Data System (ADS)

    Le Gac, Séverine; Vermes, Istvan; van den Berg, Albert

    2008-02-01

    Quantum dots (Qdots) are nanoparticles exhibiting fluorescent properties that are widely applied for cell staining. We present here the development of quantum dots for specific targeting of apoptotic cells, for both apoptosis detection and staining of apoptotic "living" cells. These Qdots are functionalized with Annexin V, a 35-kDa protein that specifically interacts with the membrane of apoptotic cells: Annexin V recognizes and binds to phosphatidylserine (PS) moieties which are present on the outer membrane of apoptotic cells and not on this of healthy or necrotic cells. By using Annexin V, our Qdots probes are made specific for apoptotic cells. For that purpose, Qdots Streptavidin Conjugates are coupled to biotinylated Annexin V. Staining of apoptotic cells was checked using fluorescence and confocal microscopy techniques on nonfixed cells. It is shown here that Qdots are insensitive to bleaching after prolonged and frequent exposure as opposed to organic dyes and this makes them excellent candidates for time-lapse imaging purposes. We illustrate the application of our Qdots-based probes to continuously follow fast changes occurring on the membrane of apoptotic cells.

  12. 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.

  13. Reduced Sampling Size with Nanopipette for Tapping-Mode Scanning Probe Electrospray Ionization Mass Spectrometry Imaging

    PubMed Central

    Kohigashi, Tsuyoshi; Otsuka, Yoichi; Shimazu, Ryo; Matsumoto, Takuya; Iwata, Futoshi; Kawasaki, Hideya; Arakawa, Ryuichi

    2016-01-01

    Mass spectrometry imaging (MSI) with ambient sampling and ionization can rapidly and easily capture the distribution of chemical components in a solid sample. Because the spatial resolution of MSI is limited by the size of the sampling area, reducing sampling size is an important goal for high resolution MSI. Here, we report the first use of a nanopipette for sampling and ionization by tapping-mode scanning probe electrospray ionization (t-SPESI). The spot size of the sampling area of a dye molecular film on a glass substrate was decreased to 6 μm on average by using a nanopipette. On the other hand, ionization efficiency increased with decreasing solvent flow rate. Our results indicate the compatibility between a reduced sampling area and the ionization efficiency using a nanopipette. MSI of micropatterns of ink on a glass and a polymer substrate were also demonstrated. PMID:28101441

  14. 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.

  15. Noncompetitive affinity assays of glucagon and amylin using mirror-image aptamers as affinity probes.

    PubMed

    Yi, Lian; Wang, Xue; Bethge, Lucas; Klussmann, Sven; Roper, Michael G

    2016-03-21

    The ability to detect picomolar concentrations of glucagon and amylin using fluorescently labeled mirror-image aptamers, so-called Spiegelmers, is demonstrated. Spiegelmers rival the specificity of antibodies and overcome the problem of biostability of natural aptamers in a biological matrix. Using Spiegelmers as affinity probes, noncompetitive capillary electrophoresis affinity assays of glucagon and murine amylin were developed and optimized. The detection limit for glucagon was 6 pM and for amylin was 40 pM. Glucagon-like peptide-1 and -2 did not interfere with the glucagon assay, while the amylin assay showed cross-reactivity to calcitonin gene related peptide. The developed assays were combined with a competitive immunoassay for insulin to measure glucagon, amylin, and insulin secretion from batches of islets after incubation with different glucose concentrations. The development of these assays is an important step towards incorporation into an online measurement system for monitoring dynamic secretion from single islets.

  16. 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

  17. 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

  18. 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.

  19. Sapphire ball lensed fiber probe for common-path optical coherence tomography in ocular imaging and sensing.

    PubMed

    Zhao, Mingtao; Huang, Yong; Kang, Jin U

    2013-03-26

    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 (TEM(00)) 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.

  20. 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.

  1. 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.

  2. 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

  3. 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

    2016-07-07

    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.

  4. 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).

  5. 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

  6. 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

  7. 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.

  8. 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.

  9. Atomic force microscopy deep trench and sidewall imaging with an optical fiber probe.

    PubMed

    Xie, Hui; Hussain, Danish; Yang, Feng; Sun, Lining

    2014-12-01

    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.

  10. 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.

  11. Application of RGD-containing peptides as imaging probes for alphavbeta3 expression.

    PubMed

    Dijkgraaf, Ingrid; Beer, Ambros J; Wester, Hans-Jurgen

    2009-01-01

    Integrin alphavbeta3 plays a pivotale role in tumor angiogenesis and is a receptor for the extracellular matrix proteins with the exposed arginine-glysine-aspartic acid (RGD) tripeptide sequence (e.g. vitronectin, fibronectin). Alphavbeta3 is overexpressed on activated endothelial cells during tumor-induced angiogenesis, whereas it is absent on quiescent endothelial cells and normal tissues. Furthermore, alphavbeta3 is expressed on various tumor cell lines. Due to this restricted expression of alphavbeta3 in tumors, alphavbeta3 is considered a suitable receptor for tumor targeting. In the past decade, several RGD-containing peptide antagonists have been evaluated for monitoring alphavbeta3 expression using SPECT, PET, MRI, OI and US. Molecular imaging tracers for this integrin receptor could be used to noninvasively visualize alphavbeta3 expression in tumors. Noninvasive determination of alphavbeta3 expression potentially can be used to monitor treatment response to antiangiogenic drugs or even to select patients likely to respond to treatment with antiangiogenic drugs. In this review a brief overview on the currently used RGD-containing peptides as imaging probes for noninvasive visualization of alphavbeta3 expression using PET, SPECT, MRI, OI and US is given.

  12. Probing the limits of paper and parchment laser cleaning by multispectral imaging

    NASA Astrophysics Data System (ADS)

    Kautek, Wolfgang; Pentzien, Simone; Mueller-Hess, Doris; Troschke, Karin; Teule, Rianne

    2001-10-01

    Paper and parchment cleaning with lasers provides the advantage to be a contact-less and dry process. The absence of chemical agents, its spectroscopic selectivity, micro-precision, computer-aided handling, and the combination with on-line diagnostic techniques makes it attractive for restoration applications. This technique, however, is not only limited by the evaporation of such delicate protein or cellulose fibre structures (i.e. the ablation threshold) or by discolorations, which can be easily detected by the naked eye or by microscopic inspection. Even when the aesthetic appearance is not altered, invisible irreversible chemical modifications may affect the long-term aging behavior negatively. In such cases, only diagnostic tools sensitive for chemical changes can probe the limits of laser cleaning. Deviations of chemical conversion threshold fluences from the well-established ablation threshold fluence values were investigated by multi-spectral imaging techniques at parchment or paper model systems and historical originals. Ultraviolet, visible and infrared reflection, but also visible fluorescence were employed using an imaging system, which operates in a spectral range from 320 nm to 1550 nm. Visible imaging allowed an accurate documentation of the color appearance of the artwork before and after the laser treatment. In-depth information of chemical modifications could be gained by the infrared imaging mode. Surface chemical identification was performed by both diffuse-reflection imaging in the ultraviolet range between 320 and 400 nm, and by visible fluorescence imaging using a 365 nm light source. The results for excimer laser treatment at 308 nm show that not only the laser fluence but also the age of the artefact strongly affects the chemical conversion threshold. Most substrates older than at least several decades exhibited much higher chemical stability than new model systems. This is a strong indication that the aging status of both parchment and

  13. 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

  14. Single-Cell Resolution Imaging of Retinal Ganglion Cell Apoptosis In Vivo Using a Cell-Penetrating Caspase-Activatable Peptide Probe

    PubMed Central

    Qiu, Xudong; Johnson, James R.; Wilson, Bradley S.; Gammon, Seth T.; Piwnica-Worms, David; Barnett, Edward M.

    2014-01-01

    Peptide probes for imaging retinal ganglion cell (RGC) apoptosis consist of a cell-penetrating peptide targeting moiety and a fluorophore-quencher pair flanking an effector caspase consensus sequence. Using ex vivo fluorescence imaging, we previously validated the capacity of these probes to identify apoptotic RGCs in cell culture and in an in vivo rat model of N-methyl- D-aspartate (NMDA)-induced neurotoxicity. Herein, using TcapQ488, a new probe designed and synthesized for compatibility with clinically-relevant imaging instruments, and real time imaging of a live rat RGC degeneration model, we fully characterized time- and dose-dependent probe activation, signal-to-noise ratios, and probe safety profiles in vivo. Adult rats received intravitreal injections of four NMDA concentrations followed by varying TcapQ488 doses. Fluorescence fundus imaging was performed sequentially in vivo using a confocal scanning laser ophthalmoscope and individual RGCs displaying activated probe were counted and analyzed. Rats also underwent electroretinography following intravitreal injection of probe. In vivo fluorescence fundus imaging revealed distinct single-cell probe activation as an indicator of RGC apoptosis induced by intravitreal NMDA injection that corresponded to the identical cells observed in retinal flat mounts of the same eye. Peak activation of probe in vivo was detected 12 hours post probe injection. Detectable fluorescent RGCs increased with increasing NMDA concentration; sensitivity of detection generally increased with increasing TcapQ488 dose until saturating at 0.387 nmol. Electroretinography following intravitreal injections of TcapQ488 showed no significant difference compared with control injections. We optimized the signal-to-noise ratio of a caspase-activatable cell penetrating peptide probe for quantitative non-invasive detection of RGC apoptosis in vivo. Full characterization of probe performance in this setting creates an important in vivo imaging

  15. 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

  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.

  17. 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

  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. Characterisation of photoaffinity-based chemical probes using fluorescence imaging and native state mass spectrometry.

    PubMed

    Teruya, Kanae; Rankin, Gregory; Chrysanthopoulos, Panagiotis; Tonissen, Kathryn; Poulsen, Sally-Ann

    2017-02-08

    Chemical probes are small molecule reagents used by researchers for labeling and detection of biomolecules. We present the design, synthesis and characterisation of a panel of eleven structurally diverse photoaffinity labeling (PAL) probes as research tools for labeling the model enzyme carbonic anhydrase (CA) in challenging environments, including protein mixtures and cell lysates. We target ubiquitous CA II as well as the two cancer associated CAs (CA IX and CA XII), which are high priority as potential biomarkers of aggressive and/or multidrug resistant cancer. We utilize an atypical biophysical approach, native state mass spectrometry, to monitor the initial protein:probe binding and subsequent UV crosslinking efficiency of the protein:probe complex. This mass spectrometry methodology represents a novel approach for chemical probe optimization and development that may have broader applications to chemical probe characterization beyond this study. This also represents one of the first studies, to our knowledge, where a comprehensive set of PAL probes was used to establish the relationship between probe structure, noncovalent protein:probe binding and covalent protein:probe crosslinking efficiency. Our results demonstrate the benefits of a comprehensive analysis of chemical probe structure-activity relationships to support the development of optimum chemical probes.

  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. 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

  3. 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.

  4. 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.

  5. Development of a terbium complex-based luminescent probe for imaging endogenous hydrogen peroxide generation in plant tissues.

    PubMed

    Ye, Zhiqiang; Chen, Jinxue; Wang, Guilan; Yuan, Jingli

    2011-06-01

    A highly sensitive Tb(3+) complex-based luminescent probe, N,N,N(1),N(1)-[2,6-(3'-aminomethyl-1'-pyrazolyl)-4-(3'',4''-diaminophenoxy)methylene-pyridine] tetrakis(acetate)-Tb(3+) (BMTA-Tb(3+)), has been designed and synthesized for the recognition and detection of hydrogen peroxide (H(2)O(2)) in aqueous solutions. This probe is almost nonluminescent because the Tb(3+) luminescence is effectively quenched by the electron-rich moiety, diaminophenyl, on the basis of the photoinduced electron transfer (PET) mechanism. In the presence of peroxidase, the probe can react with H(2)O(2) to cause the cleavage of the diaminophenyl ether, which affords a highly luminescent Tb(3+) complex, N,N,N(1),N(1)-[2,6-bis(3'-aminomethyl-1'-pyrazolyl)-4-hydroxymethyl-pyridine] tetrakis(acetate)-Tb(3+) (BHTA-Tb(3+)), accompanied by a 39-fold increase in luminescence quantum yield with the increase of luminescence lifetime from 1.95 to 2.76 ms. The dose-dependent luminescence enhancement of the probe shows a good linearity with a detection limit of 3.7 nM for H(2)O(2), which is approximately 14-fold lower than those of the commonly used fluorescent probes. The probe was used for the time-resolved luminescence imaging detection of the oligosaccharide-induced H(2)O(2) generation in tobacco leaf epidermal tissues. On the basis of the probe, a background-free time-resolved luminescence imaging method for detecting H(2)O(2) in complicated biological systems was successfully established.

  6. Terahertz near-field probe incorporating a λ/100 aperture for time-domain spectroscopy and imaging

    NASA Astrophysics Data System (ADS)

    Macfaden, Alexander J.; Reno, John L.; Brener, Igal; Mitrofanov, Oleg

    2013-12-01

    Achieving high spatial resolutions for imaging with terahertz (THz) waves requires near-field probes, such as a sub-wavelength aperture probe. Bethe's theory of transmission through a sub-wavelength aperture of size a predicts that the transmitted electric field scales as Eαa3. This strong dependence limits the size of apertures that can be employed and hence the spatial resolution. This dependence however changes for the evanescent field components in very close proximity (~1μm for THz waves) to the aperture, as shown by electromagnetic simulations. To exploit this effect in a THz near-field probe, we developed a photoconductive THz near-field detector structure, which incorporates a thinned photo-conductive detector region and a distributed Bragg reflector between the detector and the aperture plane. Near-field probes are manufactured with different aperture sizes to investigate transmission of THz pulses through apertures as small as 3μm. The experimental results confirm that the transmitted field amplitude, and therefore the sensitivity, increases by about one order of magnitude for the new probes. A 3μm aperture probe with a spatial resolution of λ/100 at 1THz is demonstrated.

  7. 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.

  8. In vivo near-infrared fluorescence imaging of amyloid-β plaques with a dicyanoisophorone-based probe.

    PubMed

    Zhu, Jia-Ying; Zhou, Lin-Fu; Li, Yu-Kun; Chen, Shuo-Bin; Yan, Jin-Wu; Zhang, Lei

    2017-04-08

    A dicyanoisophorone-based probe with two-photon absorption and NIR emission was developed for the in vivo fluorescence imaging of amyloid-β plaques, which exhibited high selectivity toward Aβ aggregates over other intracellular proteins. The detection limit was calculated to be as low as 109 nM. In vivo imaging studies indicated that the probe could penetrate the blood-brain barrier and label Aβ plaques in the living transgenic mice, and its specific binding to cerebral Aβ plaques was further confirmed by one- and two-photon ex vivo fluorescence imaging. All these results featured its promising application prospects for amyloid-β sensing in basic research and biomedical research.

  9. 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

  10. 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.

  11. Non-invasive Detection of Breast Cancer Lymph Node Metastasis using Carbonic Anhydrases IX and XII Targeted Imaging Probes

    PubMed Central

    Tafreshi, Narges K.; Bui, Marilyn M.; Bishop, Kellsey; Lloyd, Mark C.; Enkemann, Steven A.; Lopez, Alexis S.; Abrahams, Dominique; Carter, Bradford W.; Vagner, Josef; Grobmyer, Stephen R.; Gillies, Robert J.; Morse, David L.

    2014-01-01

    Purpose To develop targeted molecular imaging probes for the non-invasive detection of breast cancer lymph node metastasis. Methods Six cell surface or secreted markers were identified by expression profiling and from the literature as being highly expressed in breast cancer lymph node metastases. Two of these markers were cell surface carbonic anhydrase isozymes (CAIX and/or CAXII) and were validated for protein expression by immunohistochemistry (IHC) of patient tissue samples on a breast cancer tissue microarray containing 47 normal breast tissue samples, 42 ductal carcinoma in situ, 43 invasive ductal carcinomas without metastasis, 46 invasive ductal carcinomas with metastasis and 49 lymph node macrometastases of breast carcinoma. Targeted probes were developed by conjugation of CAIX and CAXII specific monoclonal antibodies (mAbs) to a near-infrared fluorescent dye. Results Together, these two markers were expressed in 100% of the lymph node metastases surveyed. Selectivity of the imaging probes were confirmed by intravenous injection into nude mice bearing mammary fat pad tumors of marker expressing cells, and non-expressing cells or by pre-injection of unlabeled antibody. Imaging of LN metastases showed that peritumorally-injected probes detected nodes harboring metastatic tumor cells. As few as 1,000 cells were detected, as determined by implanting, under ultrasound guidance, a range in number of CAIX and CAXII expressing cells into the axillary LNs. Conclusion These imaging probes have potential for non-invasive staging of breast cancer in the clinic and elimination of unneeded surgery, which is costly and associated with morbidities. PMID:22016510

  12. 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.

  13. Imaging thermal conductivity with nanoscale resolution using a scanning spin probe

    DOE PAGES

    Laraoui, Abdelghani; Aycock-Rizzo, Halley; Gao, Yang; ...

    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

  14. Probing articular cartilage damage and disease by quantitative magnetic resonance imaging.

    PubMed

    Chan, Deva D; Neu, Corey P

    2013-01-06

    Osteoarthritis (OA) is a debilitating disease that reflects a complex interplay of biochemical, biomechanical, metabolic and genetic factors, which are often triggered by injury, and mediated by inflammation, catabolic cytokines and enzymes. An unmet clinical need is the lack of reliable methods that are able to probe the pathogenesis of early OA when disease-rectifying therapies may be most effective. Non-invasive quantitative magnetic resonance imaging (qMRI) techniques have shown potential for characterizing the structural, biochemical and mechanical changes that occur with cartilage degeneration. In this paper, we review the background in articular cartilage and OA as it pertains to conventional MRI and qMRI techniques. We then discuss how conventional MRI and qMRI techniques are used in clinical and research environments to evaluate biochemical and mechanical changes associated with degeneration. Some qMRI techniques allow for the use of relaxometry values as indirect biomarkers for cartilage components. Direct characterization of mechanical behaviour of cartilage is possible via other specialized qMRI techniques. The combination of these qMRI techniques has the potential to fully characterize the biochemical and biomechanical states that represent the initial changes associated with cartilage degeneration. Additionally, knowledge of in vivo cartilage biochemistry and mechanical behaviour in healthy subjects and across a spectrum of osteoarthritic patients could lead to improvements in the detection, management and treatment of OA.

  15. 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 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. PMID:26584676

  16. 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.

  17. Quantitation of polymyxin-lipopolysaccharide interactions using an image-based fluorescent probe

    PubMed Central

    McInerney, MP; Roberts, KD; Thompson, PE; Li, J; Nation, RL; Velkov, T; Nicolazzo, JA

    2016-01-01

    The frequency of polymyxin-resistant pathogenic Gram-negative bacteria appearing in the clinic is increasing, and the consequences are largely mediated by modification of lipopolysaccharide (LPS) in the outer membrane. As polymyxins exert their antibacterial effect by binding to LPS, understanding their mode of binding will prove highly valuable for new antibiotic discovery. In this study, we assess the potential of MIPS-9451, a fluorescent polymyxin analogue designed for imaging studies, as a fluorescent reporter molecule, titrating it against 17 different Gram-negative species and/or strains of LPS. MIPS-9451 bound to the various species and/or strains of LPS with a dissociation constant ranging between 0.14 ± 0.01 µM (Escherichia coli) and 0.90 ± 0.42 µM (Porphyromonas gingivalis) (mean ± SE). Furthermore, we assessed the applicability of MIPS-9451 to assess affinities of polymyxin B to different LPS species in a displacement assay which yielded inhibition constants of 6.2 µM ± 33%, 7.2 µM ± 30% and 0.95 µM ± 13% for Klebsiella pneumoniae, Pseudomonas aeruginosa and Salmonella enterica, respectively (mean ± CV). The results from this study are concordant with those observed with similarly structured polymyxin probes, confirming the potential for MIPS-9451 for quantitation of polymyxin-LPS affinities in discovery programs of novel polymyxin antibiotics. PMID:26869441

  18. Ultrasensitive fluorescent ratio imaging probe for the detection of glutathione ultratrace change in mitochondria of cancer cells.

    PubMed

    Zhang, Hua; Wang, Caixia; Wang, Kui; Xuan, Xiaopeng; Lv, Qingzhang; Jiang, Kai

    2016-11-15

    Glutathione (GSH) ultratrace change in mitochondria of cancer cells can mildly and effectively induce cancer cells apoptosis in early stage. Thus, if GSH ultratrace change in mitochondria of cancer cells could be recognized and imaged, it will be beneficial for fundamental research of cancer therapy. There have reported a lot of fluorescent probes for GSH, but the fluorescent probe with ultrasensitivity and high selectivity for the ratio imaging of GSH ultratrace changes in mitochondria of cancer cells is scarce. Herein, based on different reaction mechanism of sulfonamide under different pH, a sulfonamide-based reactive ratiometric fluorescent probe (IQDC-M) was reported for the recognizing and imaging of GSH ultratrace change in mitochondria of cancer cells. The detection limit of IQDC-M for GSH ultratrace change is low to 2.02nM, which is far less than 1.0‰ of endogenic GSH in living cells. And during the recognition process, IQDC-M can emit different fluorescent signals at 520nm and 592nm, which results in it recognizing GSH ultratrace change on ratio mode. More importantly, IQDC-M recognizing GSH ultratrace change specifically occurs in mitochondria of cancer cells because of appropriate water/oil amphipathy (log P) of IQDC-M. So, these make IQDC-M possible to image and monitor GSH ultratrace change in mitochondria during cancer cells apoptosis for the first time.

  19. RGD-conjugated two-photon absorbing near-IR emitting fluorescent probes for tumor vascular imaging (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Belfield, Kevin D.; Yue, Xiling; Morales, Alma R.; Githaiga, Grace W.; Woodward, Adam W.; Tang, Simon; Sawada, Junko; Komatsu, Masanobu; Liu, Xuan

    2016-03-01

    Observation of the activation and inhibition of angiogenesis processes is important in the progression of cancer. Application of targeting peptides, such as a small peptide that contains adjacent L-arginine (R), glycine (G) and L-aspartic acid (D) residues can afford high selectivity and deep penetration in vessel imaging. To facilitate deep tissue vasculature imaging, probes that can be excited via two-photon absorption (2PA) in the near-infrared (NIR) and subsequently emit in the NIR are essential. In this study, the enhancement of tissue image quality with RGD conjugates was investigated with new NIR-emitting pyranyl fluorophore derivatives in two-photon fluorescence microscopy. Linear and nonlinear photophysical properties of the new probes were comprehensively characterized; significantly the probes exhibited good 2PA over a broad spectral range from 700-1100 nm. Cell and tissue images were then acquired and examined, revealing deep penetration and high contrast with the new pyranyl RGD-conjugates up to 350 μm in tumor tissue.

  20. RGD-conjugated Two-photon Absorbing Near-IR Emitting Fluorescent Probes for Tumor Vasculature Imaging

    PubMed Central

    Yue, Xiling; Morales, Alma R.; Githaiga, Grace W.; Woodward, Adam W.; Tang, Simon; Sawada, Junko; Komatsu, Masanobu; Liu, Xuan; Belfield, Kevin D.

    2015-01-01

    Observation of the activation and inhibition of angiogenesis processes is important in the progression of cancer. Application of targeting peptides, such as a small peptide that contains adjacent L-arginine (R), glycine (G) and L-aspartic acid (D) residues can afford high selectivity and deep penetration in vessel imaging. To facilitate deep tissue vasculature imaging, probes that can be excited via two-photon absorption (2PA) in the near-infrared (NIR) and subsequently emit in the NIR are essential. In this study, the enhancement of tissue image quality with RGD conjugates was investigated with new NIR-emitting pyranyl fluorophore derivatives in two-photon fluorescence microscopy. Linear and nonlinear photophysical properties of the new probes were comprehensively characterized; significantly the probes exhibited good 2PA over a broad spectral range from 700–1100 nm. Cell and tissue images were then acquired and examined, revealing deep penetration and high contrast with the new pyranyl RGD-conjugates up to 350 μm in tumor tissue. PMID:26351137

  1. Real-space imaging of molecular structure and chemical bonding by single-molecule inelastic tunneling probe.

    PubMed

    Chiang, Chi-lun; Xu, Chen; Han, Zhumin; Ho, W

    2014-05-23

    The arrangement of atoms and bonds in a molecule influences its physical and chemical properties. The scanning tunneling microscope can provide electronic and vibrational signatures of single molecules. However, these signatures do not relate simply to the molecular structure and bonding. We constructed an inelastic tunneling probe based on the scanning tunneling microscope to sense the local potential energy landscape of an adsorbed molecule with a carbon monoxide (CO)-terminated tip. The skeletal structure and bonding of the molecule are revealed from imaging the spatial variations of a CO vibration as the CO-terminated tip probes the core of the interactions between adjacent atoms. An application of the inelastic tunneling probe reveals the sharing of hydrogen atoms among multiple centers in intramolecular and extramolecular bonding.

  2. ADAPT, a Novel Scaffold Protein-Based Probe for Radionuclide Imaging of Molecular Targets That Are Expressed in Disseminated Cancers.

    PubMed

    Garousi, Javad; Lindbo, Sarah; Nilvebrant, Johan; Åstrand, Mikael; Buijs, Jos; Sandström, Mattias; Honarvar, Hadis; Orlova, Anna; Tolmachev, Vladimir; Hober, Sophia

    2015-10-15

    Small engineered scaffold proteins have attracted attention as probes for radionuclide-based molecular imaging. One class of these imaging probes, termed ABD-Derived Affinity Proteins (ADAPT), has been created using the albumin-binding domain (ABD) of streptococcal protein G as a stable protein scaffold. In this study, we report the development of a clinical lead probe termed ADAPT6 that binds HER2, an oncoprotein overexpressed in many breast cancers that serves as a theranostic biomarker for several approved targeting therapies. Surface-exposed amino acids of ABD were randomized to create a combinatorial library enabling selection of high-affinity binders to various proteins. Furthermore, ABD was engineered to enable rapid purification, to eradicate its binding to albumin, and to enable rapid blood clearance. Incorporation of a unique cysteine allowed site-specific conjugation to a maleimido derivative of a DOTA chelator, enabling radionuclide labeling, ¹¹¹In for SPECT imaging and ⁶⁸Ga for PET imaging. Pharmacologic studies in mice demonstrated that the fully engineered molecule (111)In/⁶⁸Ga-DOTA-(HE)3-ADAPT6 was specifically bound and taken up by HER2-expressing tumors, with a high tumor-to-normal tissue ratio in xenograft models of human cancer. Unbound tracer underwent rapid renal clearance followed by high renal reabsorption. HER2-expressing xenografts were visualized by gamma-camera or PET at 1 hour after infusion. PET experiments demonstrated feasibility for discrimination of xenografts with high or low HER2 expression. Our results offer a preclinical proof of concept for the use of ADAPT probes for noninvasive in vivo imaging.

  3. A flexible image fiber probe based speckle imaging for extraction of surface features with possible application in intra-cavity inspection

    NASA Astrophysics Data System (ADS)

    Guru, P. A. S.; Matham, Murukeshan V.; Chan, Kelvin H. K.

    2015-07-01

    Non-destructive inspection and non-invasive interrogation of surface features has always been a subject of discussion owing to the rapid advances in engineering and medical fields. Measurement of surface features which are miniature in size, inaccessible and of complex shape, has always posed challenges to conventional types of imaging and metrological systems. This paper, presents a methodology and a miniature image fiber probe configuration based on speckle technology for imaging such surface features, with possible application in intra cavity inspection. In the present work, a metal pipe is used as a test sample representing an engineering cavity. The acquired images of the intra cavity were subjected to image processing for contouring and size estimation. An analysis on the variation in the average speckle intensity, when the speckle image passes through an image fiber, is also carried out in this work. The obtained results indicate that the proposed probe configuration and related methodology can be used for inspection of cavity features and profiles of diffusive surfaces.

  4. In vivo imaging of prostate cancer using an anti-PSMA scFv fragment as a probe

    PubMed Central

    Mazzocco, Claire; Fracasso, Giulio; Germain-Genevois, Coralie; Dugot-Senant, Nathalie; Figini, Mariangela; Colombatti, Marco; Grenier, Nicolas; Couillaud, Franck

    2016-01-01

    We aimed to evaluate a fluorescent-labeled single chain variable fragment (scFv) of the anti-PSMA antibody as a specific probe for the detection of prostate cancer by in vivo fluorescence imaging. An orthotopic model of prostate cancer was generated by injecting LNCaP cells into the prostate lobe. ScFvD2B, a high affinity anti-PSMA antibody fragment, was labeled using a near-infrared fluorophore to generate a specific imaging probe (X770-scFvD2B). PSMA-unrelated scFv-X770 was used as a control. Probes were injected intravenously into mice with prostate tumors and fluorescence was monitored in vivo by fluorescence molecular tomography (FMT). In vitro assays showed that X770-scFvD2B specifically bound to PSMA and was internalized in PSMA-expressing LNCaP cells. After intravenous injection, X770-scFvD2B was detected in vivo by FMT in the prostate region. On excised prostates the scFv probe co-localized with the cancer cells and was found in PSMA-expressing cells. The PSMA-unrelated scFv used as a control did not label the prostate cancer cells. Our data demonstrate that scFvD2B is a high affinity contrast agent for in vivo detection of PSMA-expressing cells in the prostate. NIR-labeled scFvD2B could thus be further developed as a clinical probe for imaging-guided targeted biopsies. PMID:26996325

  5. Intraoperative handheld probe for 3D imaging of pediatric benign vocal fold lesions using optical coherence tomography (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Benboujja, Fouzi; Garcia, Jordan; Beaudette, Kathy; Strupler, Mathias; Hartnick, Christopher J.; Boudoux, Caroline

    2016-02-01

    Excessive and repetitive force applied on vocal fold tissue can induce benign vocal fold lesions. Children affected suffer from chronic hoarseness. In this instance, the vibratory ability of the folds, a complex layered microanatomy, becomes impaired. Histological findings have shown that lesions produce a remodeling of sup-epithelial vocal fold layers. However, our understanding of lesion features and development is still limited. Indeed, conventional imaging techniques do not allow a non-invasive assessment of sub-epithelial integrity of the vocal fold. Furthermore, it remains challenging to differentiate these sub-epithelial lesions (such as bilateral nodules, polyps and cysts) from a clinical perspective, as their outer surfaces are relatively similar. As treatment strategy differs for each lesion type, it is critical to efficiently differentiate sub-epithelial alterations involved in benign lesions. In this study, we developed an optical coherence tomography (OCT) based handheld probe suitable for pediatric laryngological imaging. The probe allows for rapid three-dimensional imaging of vocal fold lesions. The system is adapted to allow for high-resolution intra-operative imaging. We imaged 20 patients undergoing direct laryngoscopy during which we looked at different benign pediatric pathologies such as bilateral nodules, cysts and laryngeal papillomatosis and compared them to healthy tissue. We qualitatively and quantitatively characterized laryngeal pathologies and demonstrated the added advantage of using 3D OCT imaging for lesion discrimination and margin assessment. OCT evaluation of the integrity of the vocal cord could yield to a better pediatric management of laryngeal diseases.

  6. Improved accuracy and speed in scanning probe microscopy by image reconstruction from non-gridded position sensor data

    NASA Astrophysics Data System (ADS)

    Ziegler, Dominik; Meyer, Travis R.; Farnham, Rodrigo; Brune, Christoph; Bertozzi, Andrea L.; Ashby, Paul D.

    2013-08-01

    Scanning probe microscopy (SPM) has facilitated many scientific discoveries utilizing its strengths of spatial resolution, non-destructive characterization and realistic in situ environments. However, accurate spatial data are required for quantitative applications but this is challenging for SPM especially when imaging at higher frame rates. We present a new operation mode for scanning probe microscopy that uses advanced image processing techniques to render accurate images based on position sensor data. This technique, which we call sensor inpainting, frees the scanner to no longer be at a specific location at a given time. This drastically reduces the engineering effort of position control and enables the use of scan waveforms that are better suited for the high inertia nanopositioners of SPM. While in raster scanning, typically only trace or retrace images are used for display, in Archimedean spiral scans 100% of the data can be displayed and at least a two-fold increase in temporal or spatial resolution is achieved. In the new mode, the grid size of the final generated image is an independent variable. Inpainting to a few times more pixels than the samples creates images that more accurately represent the ground truth.

  7. Bipolar and fixable probe targeting mitochondria to trace local depolarization via two-photon fluorescence lifetime imaging.

    PubMed

    Wang, Benlei; Zhang, Xinfu; Wang, Chao; Chen, Lingcheng; Xiao, Yi; Pang, Yi

    2015-08-21

    Polarization/depolarization levels of different single mitochondria in a cell are inhomogeneous, and always varying. Because depolarization is an indicator of mitochondrial dysfunction, tracing local depolarization is highly desirable. The existing fluorescent probes, however, are not well suited for this task, although they are applicable to assess the average polarization extents of whole cells. A multifunctional and bipolar probe MITFPS is thus developed, which includes a positively charged hydrophilic group and an environment sensitive fluorophore. In the probe design, the hydrophilic anchoring unit is chemically immobilized on a membrane protein, while the lipophilic fluorophore can be inserted deep into the phospholipid layer. The probe exhibits a sensitive response to the local variation in polarization by changing its fluorescence lifetime. MITFPS's applicability is confirmed by real-time in situ imaging of the complete process of an uncoupler-induced depolarization under a two-photon fluorescence lifetime microscope. The imaging result reveals that one mitochondrion could have quite different polarization than the other, even though they are in the same cell.

  8. WE-G-BRF-09: Force- and Image-Adaptive Strategies for Robotised Placement of 4D Ultrasound Probes

    SciTech Connect

    Kuhlemann, I; Bruder, R; Ernst, F; Schweikard, A

    2014-06-15

    Purpose: To allow continuous acquisition of high quality 4D ultrasound images for non-invasive live tracking of tumours for IGRT, image- and force-adaptive strategies for robotised placement of 4D ultrasound probes are developed and evaluated. Methods: The developed robotised ultrasound system is based on a 6-axes industrial robot (adept Viper s850) carrying a 4D ultrasound transducer with a mounted force-torque sensor. The force-adaptive placement strategies include probe position control using artificial potential fields and contact pressure regulation by a PD controller strategy. The basis for live target tracking is a continuous minimum contact pressure to ensure good image quality and high patient comfort. This contact pressure can be significantly disturbed by respiratory movements and has to be compensated. All measurements were performed on human subjects under realistic conditions. When performing cardiac ultrasound, rib- and lung shadows are a common source of interference and can disrupt the tracking. To ensure continuous tracking, these artefacts had to be detected to automatically realign the probe. The detection is realised by multiple algorithms based on entropy calculations as well as a determination of the image quality. Results: Through active contact pressure regulation it was possible to reduce the variance of the contact pressure by 89.79% despite respiratory motion of the chest. The results regarding the image processing clearly demonstrate the feasibility to detect image artefacts like rib shadows in real-time. Conclusion: In all cases, it was possible to stabilise the image quality by active contact pressure control and automatically detected image artefacts. This fact enables the possibility to compensate for such interferences by realigning the probe and thus continuously optimising the ultrasound images. This is a huge step towards fully automated transducer positioning and opens the possibility for stable target tracking in

  9. Photoacoustic imaging of small organic molecule-based photoacoustic probe in subcutaneous tumor using P(VDF-TrFE) acoustic sensor

    NASA Astrophysics Data System (ADS)

    Hirasawa, Takeshi; Okawa, Shinpei; Kamiya, Mako; Urano, Yasuteru; Ishihara, Miya

    2015-03-01

    The P(VDF-TrFE) sensor which had uniform sensitivity in a frequency range of 2.9 - 19.6 MHz was developed for multispectral photoacoustic imaging (MS-PAI). A small organic molecule-based PA probe synthesized by our group had the absorption maximum at 530 nm and was used as a contrast agent. The PA probe was designed to have low quantum yield. Therefore, the PA probe efficiently converted absorbed optical energies to PA signals. The probe was injected in subcutaneous tumor of mice. Then, the subcutaneous tumor was imaged in vivo by using P(VDF-TrFE) sensor. MS-PAI successfully discriminated the probe signals from background signals produced from endogenous optical absorbers such as hemoglobin. The probe detectability of the P(VDF-TrFE) sensor was evaluated and then compared with that of lead zirconium titanate (PZT) sensors. The P(VDF-TrFE) sensor imaged the tumor more clearly than the PZT sensor with central frequency of 20 MHz, especially when the probe was accumulated in the tumor with low concentration. That was because the low-concentrated probe generated PA signals with low frequency. MS-PAI using P(VDF-TrFE) sensor which can detect PA signals with wide range of frequency is able to image various distribution of the probe and is superior to that using PZT sensor which detects PA signals with narrow frequency range.

  10. Submolecular Imaging by Noncontact Atomic Force Microscopy with an Oxygen Atom Rigidly Connected to a Metallic Probe.

    PubMed

    Mönig, Harry; Hermoso, Diego R; Díaz Arado, Oscar; Todorović, Milica; Timmer, Alexander; Schüer, Simon; Langewisch, Gernot; Pérez, Rubén; Fuchs, Harald

    2016-01-26

    In scanning probe microscopy, the imaging characteristics in the various interaction channels crucially depend on the chemical termination of the probe tip. Here we analyze the contrast signatures of an oxygen-terminated copper tip with a tetrahedral configuration of the covalently bound terminal O atom. Supported by first-principles calculations we show how this tip termination can be identified by contrast analysis in noncontact atomic force and scanning tunneling microscopy (NC-AFM, STM) on a partially oxidized Cu(110) surface. After controlled tip functionalization by soft indentations of only a few angstroms in an oxide nanodomain, we demonstrate that this tip allows imaging an organic molecule adsorbed on Cu(110) by constant-height NC-AFM in the repulsive force regime, revealing its internal bond structure. In established tip functionalization approaches where, for example, CO or Xe is deliberately picked up from a surface, these probe particles are only weakly bound to the metallic tip, leading to lateral deflections during scanning. Therefore, the contrast mechanism is subject to image distortions, artifacts, and related controversies. In contrast, our simulations for the O-terminated Cu tip show that lateral deflections of the terminating O atom are negligible. This allows a detailed discussion of the fundamental imaging mechanisms in high-resolution NC-AFM experiments. With its structural rigidity, its chemically passivated state, and a high electron density at the apex, we identify the main characteristics of the O-terminated Cu tip, making it a highly attractive complementary probe for the characterization of organic nanostructures on surfaces.

  11. Developing Activity Localization Fluorescence Peptide Probe Using Thiol-Ene Click Reaction for Spatially Resolved Imaging of Caspase-8 in Live Cells.

    PubMed

    Liu, Wei; Liu, Si-Jia; Kuang, Yong-Qing; Luo, Feng-Yan; Jiang, Jian-Hui

    2016-08-02

    Small molecule probes suitable for high-resolution fluorescence imaging of enzyme activity pose a challenge in chemical biology. We developed a novel design of activity localization fluorescence (ALF) peptide probe, which enables spatially resolved, highly sensitive imaging of peptidase in live cells. The ALF probe was synthesized by a facile thiol-ene click reaction of a cysteine-appended peptide with an acryloylated fluorophore. Upon cleavage by peptidase, the probe undergoes a seven-membered intramolecular cyclization and releases the fluorophore with the excited-state intramolecular photon transfer (ESIPT) effect. A highly fluorescent, insoluble aggregate was formed around the enzyme, which facilitates high-sensitivity and high-resolution imaging. This design is demonstrated for detection of caspase-8 activation. The results show that our design allows easy, high-yield synthesis of the probe, and the probe affords high sensitivity for caspase-8 detection. Live cell imaging reveals that the probe is able to render highly localized and high-contrast fluorescence signal for caspase-8. Our design holds the potential as a generally applicable strategy for developing high-sensitivity and high-resolution imaging peptide probes in cell biology and diagnostics.

  12. Can we accurately quantify nanoparticle associated proteins when constructing high-affinity MRI molecular imaging probes?

    PubMed

    Rimkus, Gabriella; Bremer-Streck, Sibylle; Grüttner, Cordula; Kaiser, Werner Alois; Hilger, Ingrid

    2011-01-01

    Targeted magnetic resonance contrast agents (e.g. iron oxide nanoparticles) have the potential to become highly selective imaging tools. In this context, quantification of the coupled amount of protein is essential for the design of antibody- or antibody fragment-conjugated nanoparticles. Nevertheless, the presence of magnetic iron oxide nanoparticles is still an unsolved problem for this task. The aim of the present work was to clarify whether proteins can be reliably quantified directly in the presence of magnetic iron oxide nanoparticles without the use of fluorescence or radioactivity. Protein quantification via Bradford was not influenced by the presence of magnetic iron oxide nanoparticles (0-17.2 mmol Fe l(-1) ). Instead, bicinchoninic acid based assay was, indeed, distinctly affected by the presence of nanoparticle-iron in suspension (0.1-17.2 mmol Fe l(-1) ), although the influence was linear. This observation allowed for adequate mathematical corrections with known iron content of a given nanoparticle. The applicability of our approach was demonstrated by the determination of bovine serum albumin (BSA) content coupled to dextrane-coated magnetic nanoparticles, which was found with the QuantiPro Bicinchoninic acid assay to be of 1.5 ± 0.2 µg BSA per 1 mg nanoparticle. Both Bradford and bicinchoninic acid assay protein assays allow for direct quantification of proteins in the presence of iron oxide containing magnetic nanoparticles, without the need for the introduction of radioactivity or fluorescence modules. Thus in future it should be possible to make more precise estimations about the coupled protein amount in high-affinity targeted MRI probes for the identification of specific molecules in living organisms, an aspect which is lacking in corresponding works published so far. Additionally, the present protein coupling procedures can be drastically improved by our proposed protein quantification method.

  13. The Functional Lumen Imaging Probe Detects Esophageal Contractility not Observed with Manometry in Patients with Achalasia

    PubMed Central

    Carlson, Dustin A.; Lin, Zhiyue; Kahrilas, Peter J.; Sternbach, Joel; Donnan, Erica N.; Friesen, Laurel; Listernick, Zoe; Mogni, Benjamin; Pandolfino, John E.

    2015-01-01

    Background & Aims The functional lumen imaging probe (FLIP) could improve characterization of achalasia subtypes by detecting non-occlusive esophageal contractions not observed with standard manometry. We aimed to evaluate for esophageal contractions during volumetric distention in patients with achalasia using FLIP topography. Methods Fifty one treatment-naïve patients with achalasia, defined and sub-classified by high-resolution esophageal pressure topography, and 10 asymptomatic individuals (controls) were evaluated with the FLIP during endoscopy. During stepwise distension, simultaneous intra-bag pressures and 16 channels of cross-sectional areas were measured; data were exported to software that generated FLIP topography plots. Esophageal contractility was identified by noting periods of reduced luminal diameter. Esophageal contractions were further characterized by propagation direction, repetitiveness, and based on whether they were occluding or non-occluding. Results Esophageal contractility was detected in all 10 controls: 8/10 had repetitive, antegrade, contractions and 9/10 had occluding contractions. Contractility was detected in 27% (4/15) of patients with type I achalasia and 65% (18/26, including 9 with occluding contractions) of patients with type II achalasia. Contractility was detected in all 10 patients with type III achalasia; 8 of these patients had a pattern of contractility not observed in controls (repetitive, retrograde contractions). Conclusions Esophageal contractility not observed with manometry can be detected in patients with achalasia using FLIP topography. The presence and patterns of contractility detected with FLIP topography may represent variations in pathophysiology, such as mechanisms of pan-esophageal pressurization in patients with type II achalasia. These findings could have implications for additional sub-classification to supplement prediction of the achalasia disease course. PMID:26278501

  14. Largely defocused probe scanning transmission electron microscopy for imaging local modulation of strain field in a hetero interface

    SciTech Connect

    Kim, Suhyun Jung, Younheum; Kim, Joong Jung; Lee, Sunyoung; Lee, Haebum; Oshima, Yoshifumi

    2014-10-13

    We present an innovative method for characterizing the strain field in three dimensions in a hetero interface. Largely defocused probe scanning transmission electron microscopy (LDP-STEM) was employed for imaging the inhomogeneous strain field in a germanium (Ge) layer deposited on a silicon (Si) substrate. In the LDP-STEM image, Ge-atomic columns that are relaxed or strained to the Si substrate in the Si/Ge hetero interface were observed to be distinguishable, allowing for the qualitative characterization of the coherency of the crystal growth. Our results revealed that the strain field is locally modulated along the in-plane direction in the Si/Ge hetero interface.

  15. Theranostic nanoshells: from probe design to imaging and treatment of cancer.

    PubMed

    Bardhan, Rizia; Lal, Surbhi; Joshi, Amit; Halas, Naomi J

    2011-10-18

    Recent advances in nanoscience and biomedicine have expanded our ability to design and construct multifunctional nanoparticles that combine targeting, therapeutic, and diagnostic functions within a single nanoscale complex. The theranostic capabilities of gold nanoshells, spherical nanoparticles with silica cores and gold shells, have attracted tremendous attention over the past decade as nanoshells have emerged as a promising tool for cancer therapy and bioimaging enhancement. This Account examines the design and synthesis of nanoshell-based theranostic agents, their plasmon-derived optical properties, and their corresponding applications. We discuss the design and preparation of nanoshell complexes and their ability to enhance the photoluminescence of fluorophores while maintaining their properties as MR contrast agents. In this Account, we discuss the underlying physical principles that contribute to the photothermal response of nanoshells. We then elucidate the photophysical processes that induce nanoshells to enhance the fluorescence of weak near-infrared fluorophores. Nanoshells illuminated with resonant light are either strong optical absorbers or scatterers, properties that give rise to their unique capabilities. These physical processes have been harnessed to visualize and eliminate cancer cells. We describe the application of nanoshells as a contrast agent for optical coherence tomography of breast carcinoma cells in vivo. Our recent studies examine nanoshells as a multimodal theranostic probe, using these nanoparticles for near-infrared fluorescence and magnetic resonance imaging (MRI) and for the photothermal ablation of cancer cells. Multimodal nanoshells show theranostic potential for imaging subcutaneous breast cancer tumors in animal models and the distribution of tumors in various tissues. Nanoshells also show promise as light-triggered gene therapy vectors, adding temporal control to the spatial control characteristic of nanoparticle-based gene

  16. Combining high-dispersion spectroscopy with high contrast imaging: Probing rocky planets around our nearest neighbors

    NASA Astrophysics Data System (ADS)

    Snellen, I.; de Kok, R.; Birkby, J. L.; Brandl, B.; Brogi, M.; Keller, C.; Kenworthy, M.; Schwarz, H.; Stuik, R.

    2015-04-01

    Context. Ground-based high-dispersion (R ~ 100 000) spectroscopy (HDS) is proving to be a powerful technique with which to characterize extrasolar planets. The planet signal is distilled from the bright starlight, combining ral and time-differential filtering techniques. In parallel, high-contrast imaging (HCI) is developing rapidly, aimed at spatially separating the planet from the star. While HDS is limited by the overwhelming noise from the host star, HCI is limited by residual quasi-static speckles. Both techniques currently reach planet-star contrast limits down to ~10-5, albeit for very different types of planetary systems. Aims: In this work, we discuss a way to combine HDS and HCI (HDS+HCI). For a planet located at a resolvable angular distance from its host star, the starlight can be reduced up to several orders of magnitude using adaptive optics and/or coronography. In addition, the remaining starlight can be filtered out using high-dispersion spectroscopy, utilizing the significantly different (or Doppler shifted) high-dispersion spectra of the planet and star. In this way, HDS+HCI can in principle reach contrast limits of ~10-5 × 10-5, although in practice this will be limited by photon noise and/or sky-background. In contrast to current direct imaging techniques, such as Angular Differential Imaging and Spectral Differential Imaging, it will work well at small working angles and is much less sensitive to speckle noise. For the discovery of previously unknown planets HDS+HCI requires a high-contrast adaptive optics system combined with a high-dispersion R ~ 100 000 integral field spectrograph (IFS). This combination currently does not exist, but is planned for the European Extremely Large Telescope. Methods: We present simulations of HDS+HCI observations with the E-ELT, both probing thermal emission from a planet at infrared wavelengths, and starlight reflected off a planet atmosphere at optical wavelengths. For the infrared simulations we use the

  17. Chemically-activatable alkyne-tagged probe for imaging microdomains in lipid bilayer membranes

    PubMed Central

    Yamaguchi, Satoshi; Matsushita, Taku; Izuta, Shin; Katada, Sumika; Ura, Manami; Ikeda, Taro; Hayashi, Gosuke; Suzuki, Yuta; Kobayashi, Koya; Tokunaga, Kyoya; Ozeki, Yasuyuki; Okamoto, Akimitsu

    2017-01-01

    A chemically-activatable alkynyl steroid analogue probe has been synthesized for visualizing the lipid raft membrane domains by Raman microscopy. The Raman probe, in which ring A of its steroid backbone is replaced with an alkynyl group, was designed to enable activation of the alkyne signal through the Eschenmoser-Tanabe fragmentation reaction of the oxidized cholesterol precursor in lipid bilayer membranes. The alkynyl steroid analogue was observed to form liquid-ordered raft-like domains on a model giant-liposome system in a similar manner as cholesterol, and the large alkyne signal of the accumulated probe at 2120 cm−1 was mapped on the microdomains with a Raman microscope. The alkyne moiety of the probe was confirmed to be converted from the α,β-epoxy ketone group of its precursor by reaction with p-toluensulfonyl hydrazine under a mild condition. Through the reaction, the alkyne signal of the probe was activated on the lipid bilayer membrane of liposomes. Furthermore, the signal activation of the probe was also detected on living cells by stimulated Raman scattering microscopy. The ring-A-opened alkyne steroid analogue, thus, provides a first chemically-activatable Raman probe as a promising tool for potentially unravelling the intracellular formation and trafficking of cholesterol-rich microdomains. PMID:28117375

  18. Use of endoscopic distal attachment cap to enhance image stabilization in probe-based confocal laser endomicroscopy in colorectal lesions*

    PubMed Central

    Ussui, Vivian; Xu, Can; Crook, Julia E.; Diehl, Nancy N.; Hardee, Joy; Staggs, Estela G.; Shahid, Muhammad W.; Wallace, Michael B.

    2015-01-01

    Background and study aims: Colorectal cancer can be prevented through the use of colonoscopy with polypectomy. Most colon polyps are benign or low grade adenomas. However, currently all lesions need histopathologic analysis, which increases diagnostic costs and delays the final diagnosis. Confocal laser endomicroscopy (CLE) is a new technology that enables real-time endomicroscopy. However, there are challenges to maintaining a stable image with currently available systems. We conducted a small study to obtain a preliminary assessment of whether the use of an endoscopic distal attachment cap may enhance image quality of CLE in comparison with images obtained with free-hand acquisition. Patients and methods: Forty outpatients underwent colonoscopy for evaluation of colon polyps in a single academic medical center. Patients were assigned randomly to 1 of 2 study arms on the basis of whether an endoscopic distal attachment cap was used (n = 21, Cap Used) or not used (n = 19, No Cap) in the procedure. The quality of confocal images and probe stabilization was summarized. Results: A total of 81 polyps were identified. The proportion of polyps with images of high quality was 74 % (28/38) in the Cap Used group and 79 % (30/38) in the No Cap arm. Image stability was also similar with and without a cap. Diagnostic accuracy was estimated to be slightly higher in the Cap Used group for probe-based confocal laser endomicroscopy (pCLE; 78 % vs 70 %). This was also true for white-light and narrow-band imaging. Conclusions: This preliminary study did not yield any evidence to support that the use of an endoscopic distal attachment cap improves the quality of images obtained during CLE. PMID:26528511

  19. In vivo proton-electron double-resonance imaging of extracellular tumor pH using an advanced nitroxide probe.

    PubMed

    Samouilov, Alexandre; Efimova, Olga V; Bobko, Andrey A; Sun, Ziqi; Petryakov, Sergey; Eubank, Timothy D; Trofimov, Dmitrii G; Kirilyuk, Igor A; Grigor'ev, Igor A; Takahashi, Wataru; Zweier, Jay L; Khramtsov, Valery V

    2014-01-21

    A variable radio frequency proton-electron double-resonance imaging (VRF PEDRI) approach for pH mapping of aqueous samples has been recently developed (Efimova et al. J. Magn. Reson. 2011, 209, 227-232). A pH map is extracted from two PEDRI acquisitions performed at electron paramagnetic resonance (EPR) frequencies of protonated and unprotonated forms of a pH-sensitive probe. To translate VRF PEDRI to an in vivo setting, an advanced pH probe was synthesized. Probe deuteration resulted in a narrow spectral line of 1.2 G compared to a nondeuterated analogue line width of 2.1 G allowing for an increase of Overhauser enhancements and reduction in rf power deposition. Binding of the probe to the cell-impermeable tripeptide, glutathione (GSH), allows for targeting to extracellular tissue space for monitoring extracellular tumor acidosis, a prognostic factor in tumor pathophysiology. The probe demonstrated pH sensitivity in the 5.8-7.8 range, optimum for measurement of acidic extracellular tumor pH (pH(e)). In vivo VRF PEDRI was performed on Met-1 tumor-bearing mice. Compared to normal mammary glands with a neutral mean pH(e) (7.1 ± 0.1), we observed broader pH distribution with acidic mean pH(e) (6.8 ± 0.1) in tumor tissue. In summary, VRF PEDRI in combination with a newly developed pH probe provides an analytical approach for spatially resolved noninvasive pHe monitoring, in vivo.

  20. Efficient two-photon fluorescent probe with red emission for imaging of thiophenols in living cells and tissues.

    PubMed

    Liu, Hong-Wen; Zhang, Xiao-Bing; Zhang, Jing; Wang, Qian-Qian; Hu, Xiao-Xiao; Wang, Peng; Tan, Weihong

    2015-09-01

    Thiophenols, a class of highly toxic and pollutant compounds, are widely used in industrial production. Some aliphatic thiols play important roles in living organisms. Therefore, the development of efficient methods to discriminate thiophenols from aliphatic thiols is of great importance. Although several one-photon fluorescent probes have been reported for thiophenols, two-photon fluorescent probes are more favorable for biological imaging due to its low background fluorescence, deep penetration depth, and so on. In this work, a two-photon fluorescent probe for thiophenols, termed NpRb1, has been developed for the first time by employing 2,4-dinitrobenzene-sulfonate (DNBS) as a recognition unit (also a fluorescence quencher) and a naphthalene-BODIPY-based through-bond energy transfer (TBET) cassette as a fluorescent reporter. The TBET system consists of a D-π-A structured two-photon naphthalene fluorophore and a red-emitting BODIPY. It displayed highly energy transfer efficiency (93.5%), large pseudo-Stokes shifts upon one-photon excitation, and red fluorescence emission (λem = 586 nm), which is highly desirable for bioimaging applications. The probe exhibited a 163-fold thiophenol-triggered two-photon excited fluorescence enhancement at 586 nm. It showed a high selectivity and excellent sensitivity to thiophenols, with a detection limit of 4.9 nM. Moreover, it was successfully applied for practical detection of thiophenol in water samples with a good recovery, two-photon imaging of thiophenol in living cells, and tissues with tissue-imaging depths of 90-220 μm, demonstrating its practical application in environmental samples and biological systems.

  1. Self-Assembly of Peptide Amphiphiles Designed as Imaging Probes for 19F and Relaxation-Enhanced 1H imaging

    NASA Astrophysics Data System (ADS)

    Preslar, Adam Truett

    This work incorporates whole-body imaging functionality into peptide amphiphile (PA) nanostructures used for regenerative medicine to facilitate magnetic resonance imaging (MRI). Two strategies were employed: 1. Conjugation of gadolinium chelates to peptide nanostructures to monitor biomaterial degradation in vivo with MRI and inductively-coupled plasma-mass spectroscopy (ICP-MS) 2. Synthesis of perfluorinated moiety-bearing peptide amphiphiles for 19F-MRI. The Gd(III) chelate gadoteridol was conjugated by copper-catalyzed "click" chemistry to a series of PAs known to form cylindrical nanostructures. By fitting nuclear magnetic resonance dispersion (NMRD) profiles to the Solomon-Bloembergen-Morgan (SBM) equations, it was observed that the water exchange parameter (tauM) depended on thermal annealing or calcium ion cross-linking. The sequence C16V 3A3E3G(Gd) exhibited an acceleration of nearly 100 ns after thermal annealing and calcium addition. These gadolinium-labeled PAs were used to track in vivo degradation of gels within the tibialis anterior muscle in a murine model. The half-life of biomaterial degradation was determined to be 13.5 days by inductively coupled plasma mass spectrometry (ICP-MS) of Gd(III). Gel implants could be monitored by MRI for eight days before the signal dispersed due to implant degradation and dilution. Additionally, nanostructures incorporating highly fluorinated domains were investigated for use as MRI contrast agents. Short, perfluoroalkyane tails of seven or eight carbon atoms in length were grafted to PA sequences containing a V2A2 beta-sheet forming sequence. The V2A2 sequence is known to drive 1D nanostructure assembly. It was found that the sequences C7F13V2A 2E2 and C7F13V2A 2K3 formed 1D assemblies in water which transition from ribbon-like to cylindrical shape as pH increases from 4.5 to 8.0. Ribbon-like nanostructures had reduced magnetic resonance signal by T 2 relaxation quenching, whereas their cylindrical counterparts

  2. Effect of using different U/S probe Standoff materials in image geometry for interventional procedures: the example of prostate

    PubMed Central

    Diamantopoulos, Stefanos; Butt, Saeed; Katsilieri, Zaira; Kefala, Vasiliki; Zogal, Pawel; Sakas, George; Baltas, Dimos

    2011-01-01

    Purpose This study investigates the distortion of geometry of catheters and anatomy in acquired U/S images, caused by utilizing various stand-off materials for covering a transrectal bi-planar ultrasound probe in HDR and LDR prostate brachytherapy, biopsy and other interventional procedures. Furthermore, an evaluation of currently established water-bath based quality assurance (QA) procedures is presented. Material and methods Image acquisitions of an ultrasound QA setup were carried out at 5 MHz and 7 MHz. The U/S probe was covered by EA 4015 Silicone Standoff kit, or UA0059 Endocavity balloon filled either with water or one of the following: 40 ml of Endosgel®, Instillagel®, Ultraschall gel or Space OAR™ gel. The differences between images were recorded. Consequently, the dosimetric impact of the observed image distortion was investigated, using a tissue equivalent ultrasound prostate phantom – Model number 053 (CIRS Inc., Norfolk, VA, USA). Results By using the EA 4015 Silicone Standoff kit in normal water with sound speed of 1525 m/s, a 3 mm needle shift was observed. The expansion of objects appeared in radial direction. The shift deforms also the PTV (prostate in our case) and other organs at risk (OARs) in the same way leading to overestimation of volume and underestimation of the dose. On the other hand, Instillagel® and Space OAR™ “shrinks” objects in an ultrasound image for 0.65 mm and 0.40 mm, respectively. Conclusions The use of EA 4015 Silicone Standoff kit for image acquisition, leads to erroneous contouring of PTV and OARs and reconstruction and placement of catheters, which results to incorrect dose calculation during prostate brachytherapy. Moreover, the reliability of QA procedures lies mostly in the right temperature of the water used for accurate simulation of real conditions of transrectal ultrasound imaging. PMID:23346130

  3. Molecular imaging probes spy on the body's inner workings: miniaturized microscopes, microbubbles, 7- and 15-T scanners, diffusion-tensor MRI, and other molecular-imaging technologies are pushing molecular imaging into the future.

    PubMed

    Mertz, Leslie

    2013-01-01

    Molecular imaging is one of the hot-button areas within medical imaging. This technology employs imaging techniques in concert with molecular probes, or biomarkers, that together noninvasively spy on cellular function and molecular processes. In some cases, this technology may be able to detect the very earliest stages of diseases and eliminate them on the spot. This paper discusses how miniaturized microscopes, microbubbles, 7T and 15T scanners, diffusion-tensor MRI and other molecular imaging technologies are pushing molecular imaging into the future.

  4. Label-Free Imaging of Female Genital Tract Melanocytic Lesions With Pump-Probe Microscopy: A Promising Diagnostic Tool

    PubMed Central

    Robles, Francisco E.; Deb, Sanghamitra; Fischer, Martin C.; Warren, Warren S.; Selim, Maria Angelica

    2017-01-01

    Objectives Melanomas of the female genital tract present a unique clinical challenge. Not only are these lesions in an anatomically sensitive area, but also they tend to be multifocal and have high recurrence rates. Furthermore, several benign melanocytic proliferations resemble early-stage melanoma clinically and/or histopathologically. Thus, there is a significant need for additional tools that can help correctly diagnose and stage these lesions. Here, we quantitatively and nondestructively analyze the chemical composition of melanin in excised pigmented lesions of the female genital tract using pump-probe microscopy, a high-resolution optical imaging technique that is sensitive to many biochemical properties of melanin. Materials and Methods Thirty-one thin (~5 μm) tissue sections previously excised from female genital tract melanocytic lesions were imaged with pump-probe microscopy and analyzed. Results We find significant quantitative differences in melanin type and structure between melanoma and nonmalignant melanocytic proliferations. Our analysis also suggests a link between the molecular signatures of melanins and lesion-specific genetic mutations. Finally, significant differences are found between metastatic and nonmetastatic melanomas. The limitations of this work include the fact that molecular information is restricted to melanin pigment and the sample size is relatively small. Conclusions Pump-probe microscopy provides unique information regarding the biochemical composition of genital tract melanocytic lesions, which can be used to improve the diagnosis and staging of vulvar melanomas. PMID:28157824

  5. A two-photon NIR-to-NIR fluorescent probe for imaging hydrogen peroxide in living cells.

    PubMed

    Li, Haidong; Yao, Qichao; Fan, Jiangli; Du, Jianjun; Wang, Jingyun; Peng, Xiaojun

    2017-03-19

    Hydrogen peroxide (H2O2), one of the reactive oxygen species (ROS), plays vital roles in diverse physiological processes. Imbalance of the H2O2 is concerned with serious diseases such as cardiovascular disorders, neurodegenerative diseases, Alzheimer's disease and cancer. Therefore, it is critical to develop efficient methods for monitoring H2O2 in vivo. In this work, a two-photon excitation (860nm) NIR fluorescent turn-on probe TPNR-H2O2 for H2O2 based on Dicyanomethylene-4H-pyran fluorophore is reported, which can be used in solution detection with 13.2-fold NIR fluorescence enhancement, fast response (completed within 40min), excellent sensitivity (DL 72.48nM), and lower cellular auto-fluorescence interference. Importantly, the perfect photostability of TPNR-H2O2 clearly demonstrated that the probe could be applied to imaging intracellular H2O2 for a long time without photobleaching. In addition, through two-photon imaging, this probe was cell permeable and used to monitor the level of endogenous and exogenous H2O2 with promising biological application.

  6. Rational design of reversible fluorescent probes for live-cell imaging and quantification of fast glutathione dynamics

    NASA Astrophysics Data System (ADS)

    Umezawa, Keitaro; Yoshida, Masafumi; Kamiya, Mako; Yamasoba, Tatsuya; Urano, Yasuteru

    2016-11-01

    Alterations in glutathione (GSH) homeostasis are associated with a variety of diseases and cellular functions, and therefore, real-time live-cell imaging and quantification of GSH dynamics are important for understanding pathophysiological processes. However, existing fluorescent probes are unsuitable for these purposes due to their irreversible fluorogenic mechanisms or slow reaction rates. In this work, we have successfully overcome these problems by establishing a design strategy inspired by Mayr's work on nucleophilic reaction kinetics. The synthesized probes exhibit concentration-dependent, reversible and rapid absorption/fluorescence changes (t1/2 = 620 ms at [GSH] = 1 mM), as well as appropriate Kd values (1-10 mM: within the range of intracellular GSH concentrations). We also developed FRET-based ratiometric probes, and demonstrated that they are useful for quantifying GSH concentration in various cell types and also for real-time live-cell imaging of GSH dynamics with temporal resolution of seconds.

  7. 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.

  8. Azobenzene-caged sulforhodamine dyes: a novel class of ‘turn-on’ reactive probes for hypoxic tumor cell imaging

    NASA Astrophysics Data System (ADS)

    Chevalier, Arnaud; Piao, Wen; Hanaoka, Kenjiro; Nagano, Tetsuo; Renard, Pierre-Yves; Romieu, Anthony

    2015-12-01

    New sulforhodamine-based fluorescent ‘turn-on’ probes have been developed for the direct imaging of cellular hypoxia. Rapid access to this novel class of water-soluble ‘azobenzene-caged’ fluorophores was made possible through an easily-implementable azo-coupling reaction between a fluorescent primary arylamine derived from a sulforhodamine 101 scaffold (named SR101-NaphtNH 2 ) and a tertiary aniline whose N-substituents are neutral, cationic, or zwitterionic. The detection mechanism is based on the bioreductive cleavage of the azo bond that restores strong far-red fluorescence (emission maximum at 625 nm) by regenerating the original sulforhodamine SR101-NaphtNH 2 . This valuable fluorogenic response was obtained for the three ‘smart’ probes studied in this work, as shown by an in vitro assay using rat liver microsomes placed under aerobic and then under hypoxic conditions. Most importantly, the probe namely SR101-NaphtNH 2 -Hyp-diMe was successfully applied for imaging the hypoxic status of tumor cells (A549 cells).

  9. Probing the Brain in Autism Using fMRI and Diffusion Tensor Imaging

    PubMed Central

    Kana, Rajesh K.; Murdaugh, Donna L.; Libero, Lauren E.; Pennick, Mark R.; Wadsworth, Heather M.; Deshpande, Rishi; Hu, Christi P.

    2011-01-01

    well established, we can begin to further understand brain connectivity as a critical component of autism symptomatology. A logical next step in this direction is to examine the anatomical connections that may mediate the functional connections mentioned above. Diffusion Tensor Imaging (DTI) is a relatively novel neuroimaging technique that helps probe the diffusion of water in the brain to infer the integrity of white matter fibers. In this technique, water diffusion in the brain is examined in several directions using diffusion gradients. While functional connectivity provides information about the synchronization of brain activation across different brain areas during a task or during rest, DTI helps in understanding the underlying axonal organization which may facilitate the cross-talk among brain areas. This paper will describe these techniques as valuable tools in understanding the brain in autism and the challenges involved in this line of research. PMID:21931296

  10. A new endoplasmic reticulum-targeted two-photon fluorescent probe for imaging of superoxide anion in diabetic mice.

    PubMed

    Xiao, Haibin; Liu, Xiao; Wu, Chuanchen; Wu, Yaohuan; Li, Ping; Guo, Xiaomeng; Tang, Bo

    2017-05-15

    Excessive or unfolded proteins accumulation in endoplasmic reticulum (ER) will cause ER stress, which has evolved to involve in various metabolic diseases. In particular, ER stress plays an important role in the pathogenesis of diabetes. Both ER stress and course of diabetes accompany oxidative stress and production of reactive oxygen species (ROS), among which superoxide anion (O2(•-)) is the first produced ROS and has been recognized as cell signaling mediator involved in the physiological and pathological process of diabetes. Hence, the development of effective monitoring methods of O2(•-) in live cells and in vivo is of great importance for ascertaining the onset and progress of related diseases. Herein, a new endoplasmic reticulum-targeted two-photon fluorescent probe termed ER-BZT is designed and synthesized for imaging of O2(•-). The probe ER-BZT shows high sensitivity, selectivity, stability, and low cytotoxicity. Based on these superior properties, the rise of O2(•-) levels in endoplasmic reticulum induced with different stimuli is visualized by one- and two-photon fluorescence imaging. Most importantly, by utilizing ER-BZT, the two-photon fluorescence imaging results demonstrate that the endogenous O2(•-) concentration in abdominal or hepatic tissue of diabetic mice is higher than that in normal mice. Meanwhile, after treated with metformin, a broad-spectrum antidiabetic drug, the diabetic mice exhibit depressed O2(•-) level. The proposed two-photon probe, ER-BZT might serve as perfect tool to image the O2(•-) fluctuations and study the relevance between O2(•-) and various diseases in live cells and in vivo.

  11. Non-contact high resolution Bessel beam probe for diagnostic imaging of cornea and trabecular meshwork region in eye

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

    Primary angle closure glaucoma is a major form of disease that causes blindness in Asia and worldwide. In glaucoma, irregularities in the ocular aqueous outflow system cause an elevation in intraocular pressure (IOP) with subsequent death of retinal ganglion cells, resulting in loss of vision. High resolution visualization of the iridocorneal angle region has great diagnostic value in understanding the disease condition which enables monitoring of surgical interventions that decrease IOP. None of the current diagnostic techniques such as goniophotography, ultrasound biomicroscopy (UBM), anterior segment optical coherence tomography (AS-OCT) and RetCam™ can image with molecular specificity and required spatial resolution that can delineate the trabecular meshwork structures. This paper in this context proposes new concepts and methodology using Bessel beams based illumination and imaging for such diagnostic ocular imaging applications. The salient features using Bessel beams instead of the conventional Gaussian beam, and the optimization challenges in configuring the probe system will be illustrated with porcine eye samples.

  12. A scanning Hall probe microscope for high resolution, large area, variable height magnetic field imaging

    NASA Astrophysics Data System (ADS)

    Shaw, Gorky; Kramer, R. B. G.; Dempsey, N. M.; Hasselbach, K.

    2016-11-01

    We present a scanning Hall probe microscope operating in ambient conditions. One of the unique features of this microscope is the use of the same stepper motors for both sample positioning as well as scanning, which makes it possible to have a large scan range (few mm) in the x and y directions, with a scan resolution of 0.1 μm. Protocols have been implemented to enable scanning at different heights from the sample surface. The z range is 35 mm. Microstructured Hall probes of size 1-5 μm have been developed. A minimum probe-sample distance <2 μm has been obtained by the combination of new Hall probes and probe-sample distance regulation using a tuning fork based force detection technique. The system is also capable of recording local B(z) profiles. We discuss the application of the microscope for the study of micro-magnet arrays being developed for applications in micro-systems.

  13. Imaging of caspase-3 activation by a novel FRET probe composed of CFP and DsRed

    NASA Astrophysics Data System (ADS)

    Lin, Juquiang; Zhang, Zhihong; Liu, Bifeng; Luo, Qingming

    2006-01-01

    Caspases-3 is a kind of cysteine proteases and plays an important role in cell apoptosis. It has been reported that caspase-3 activation can be real-time detected in living cells by fluorescence resonance energy transfer (FRET) between an enhanced cyan fluorescent protein and enhanced yellow fluorescent protein. However, the large spectral overlap between cyan fluorescent protein (CFP) and yellow fluorescent protein (YFP) emission and the highly sensitivity to pH of YFP restricted their detecting sensitivity and reliability. CFP and red fluorescent protein (DsRed) possess superb wavelength separation of donor and acceptor emission spectra and DsRed was insensitive to pH, so the FRET probe composed of CFP and DsRed would be more suitable for imaging caspase-3 activation than the FRET probe composed of CFP and YFP. We constructed a vector that encoded CRS (caspase-3 recognition site) fused with CFP and DsRed (CFP-CRS-DsRed). In CFP-CRS-DsRed expressing tumor cells, FRET from CFP to DsRed could be detected. In the Clinical applications of cancer chemotherapy, cisplatin is one of the most broadly used drugs. It was already confirmed that caspase-3 was activated in HeLa cell treated by cisplatin. When the cells were stimulated with cisplatin, we found that the FRET efficient was remarkably decreased and then disappeared. It indicated that actived caspase-3 cleaved the CFP-CRS-DsRed fusion protein at CRS site. Thus, the FRET probe of CFP-CRS-DsRed could sensitively and reliably monitor caspase-3 activation in living cell. This probe will be highly useful for rapid-screening potential drugs that may target the apoptotic process and for imaging tumors in vivo.

  14. Single action potentials and subthreshold electrical events imaged in neurons with a fluorescent protein voltage probe.

    PubMed

    Jin, Lei; Han, Zhou; Platisa, Jelena; Wooltorton, Julian R A; Cohen, Lawrence B; Pieribone, Vincent A

    2012-09-06

    Monitoring neuronal electrical activity using fluorescent protein-based voltage sensors has been limited by small response magnitudes and slow kinetics of existing probes. Here we report the development of a fluorescent protein voltage sensor, named ArcLight, and derivative probes that exhibit large changes in fluorescence intensity in response to voltage changes. ArcLight consists of the voltage-sensing domain of Ciona intestinalis voltage-sensitive phosphatase and super ecliptic pHluorin that carries the point mutation A227D. The fluorescence intensity of ArcLight A242 decreases by 35% in response to a 100 mV depolarization when measured in HEK293 cells, which is more than five times larger than the signals from previously reported fluorescent protein voltage sensors. We show that the combination of signal size and response speed of these new probes allows the reliable detection of single action potentials and excitatory potentials in individual neurons and dendrites.

  15. Development of novel FP-based probes for live-cell imaging of nitric oxide dynamics

    PubMed Central

    Eroglu, Emrah; Gottschalk, Benjamin; Charoensin, Suphachai; Blass, Sandra; Bischof, Helmut; Rost, Rene; Madreiter-Sokolowski, Corina T.; Pelzmann, Brigitte; Bernhart, Eva; Sattler, Wolfgang; Hallström, Seth; Malinski, Tadeusz; Waldeck-Weiermair, Markus; Graier, Wolfgang F.; Malli, Roland

    2016-01-01

    Nitric oxide () is a free radical with a wide range of biological effects, but practically impossible to visualize in single cells. Here we report the development of novel multicoloured fluorescent quenching-based probes by fusing a bacteria-derived -binding domain close to distinct fluorescent protein variants. These genetically encoded probes, referred to as geNOps, provide a selective, specific and real-time read-out of cellular dynamics and, hence, open a new era of bioimaging. The combination of geNOps with a Ca2+ sensor allowed us to visualize and Ca2+ signals simultaneously in single endothelial cells. Moreover, targeting of the probes was used to detect signals within mitochondria. The geNOps are useful new tools to further investigate and understand the complex patterns of signalling on the single (sub)cellular level. PMID:26842907

  16. Activity-Based Probes linked with Laser-Cleavable Mass Tags for Signal Amplification in Imaging Mass Spectrometry: Analysis of Serine Hydrolase Enzymes in Mammalian Tissue

    PubMed Central

    Yang, Junhai; Chaurand, Pierre; Norris, Jeremy L.; Porter, Ned A.; Caprioli, Richard M.

    2012-01-01

    A novel functional Imaging Mass Spectrometry technology is described that utilizes activity-based probes for imaging enzyme active sites in tissue sections. We demonstrate this technology using an activity-based probe (fluorophosphate) that is specific for serine hydrolases. A dendrimer containing multiple mass tags that is attached to the activity-based probe is used to analyze the binding sites of the probe through release and measurement of the mass tags on laser irradiation. A generation 8 Poly(amido amine) dendrimer with 1024 amino groups was labeled with an azide group and then more than 900 mass tags were attached in order to achieve signal amplification of nearly three orders of magnitude. The experimental protocol first involves binding of the activity-based probe containing an alkyne group to serine hydrolases in the tissue section followed by attachment of the dendrimer labeled with mass tags to the bound probe by Click chemistry. On irradiation of the labeled tissue by the laser beam in a raster pattern, the mass tags are liberated and recorded by the mass analyzer, consequently, the ion image of the mass tag reveals the distribution of serine hydrolases in the tissue. This process was shown using rat brain and mouse embryo sections. Targeted imaging has the advantage of providing high spatial resolution and high sensitivity through the use of signal amplification chemistry with high target specificity through the use of an enzyme activity probe. PMID:22424244

  17. Turn-on persistent luminescence probe based on graphitic carbon nitride for imaging detection of biothiols in biological fluids.

    PubMed

    Tang, Yurong; Song, Hongjie; Su, Yingying; Lv, Yi

    2013-12-17

    Herein, we present a novel strategy based on a "turn-on" persistent luminescence imaging chemical system of graphitic carbon nitride for detecting biothiols in biological fluids. Graphitic carbon nitride (g-C3N4) as persistent luminescence probe is fabricated via a new procedure based on pyrolysis of guanidine hydrochloride under ambient atmospheric conditions. The prepared g-C3N4 nanosheets give intensively long-persistent luminescence that can avoid interference from biological media such as tissue autofluorescence and scattering light. The original persistent luminescence of g-C3N4 turns off due to the adsorption of silver ion (Ag(+)) onto g-C3N4 materials with an electron transfer process. The presence of biothiols induces the onset of persistent luminescence emission by interrupting the quenching interaction, thereby turning on the imaging probe. The approach exhibits high specificity and high sensitivity to biothiols with low detection limit for cysteine (Cys), homocysteine (Hcy), and glutathione (GSH) with 6.4, 8.1, and 9.6 nM, respectively. It is also successfully applied for imaging detection of biothiols in human urine, plasma, and cell lysates, demonstrating its great value of practical application in biological systems.

  18. An Evanescent Microwave Probe for Super-Resolution Nondestructive Imaging of Metals, Semiconductors, Dielectrics, Composites and Biological Specimens

    NASA Technical Reports Server (NTRS)

    Pathak, P. S.; Tabib-Azar, M.; Ponchak, G.

    1998-01-01

    Using evanescent microwaves with decay lengths determined by a combination of microwave wavelength (lambda) and waveguide termination geometry, we have imaged and mapped material non-uniformities and defects with a resolving capability of lambda/3800=79 microns at 1 GHz. In our method a microstrip quarter wavelength resonator was used to generate evanescent microwaves. We imaged materials with a wide range of conductivities. Carbon composites, dielectrics (Duroid, polymers), semiconductors (3C-SiC, polysilicon, natural diamond), metals (tungsten alloys, copper, zinc, steel), high-temperature superconductors, and botanical samples were scanned for defects, residual stresses, integrity of brazed junctions, subsurface features, areas of different film thickness and moisture content. The evanescent microwave probe is a versatile tool and it can be used to perform very fast, large scale mapping of a wide range of materials. This method of characterization compares favorably with ultrasound testing, which has a resolution of about 0.1 mm and suffers from high absorption in composite materials and poor transmission across boundaries. Eddy current methods which can have a resolution on the order of 50 microns are restricted to evaluating conducting materials. Evanescent microwave imaging, with careful choice of operating frequency and probe geometry, can have a resolution of up to 1 micron. In this method we can scan hot and moving objects, sample preparation is not required, testing is non-destructive, non-invasive and non-contact, and can be done in air, in liquid or in vacuum.

  19. pHLIP-FIRE, a cell insertion-triggered fluorescent probe for imaging tumors demonstrates targeted cargo delivery in vivo.

    PubMed

    Karabadzhak, Alexander G; An, Ming; Yao, Lan; Langenbacher, Rachel; Moshnikova, Anna; Adochite, Ramona-Cosmina; Andreev, Oleg A; Reshetnyak, Yana K; Engelman, Donald M

    2014-11-21

    We have developed an improved tool for imaging acidic tumors by reporting the insertion of a transmembrane helix: the pHLIP-Fluorescence Insertion REporter (pHLIP-FIRE). In acidic tissues, such as tumors, peptides in the pHLIP family insert as α-helices across cell membranes. The cell-inserting end of the pHLIP-FIRE peptide has a fluorophore-fluorophore or fluorophore-quencher pair. A pair member is released by disulfide cleavage after insertion into the reducing environment inside a cell, resulting in dequenching of the probe. Thus, the fluorescence of the pHLIP-FIRE probe is enhanced upon cell-insertion in the targeted tissues but is suppressed elsewhere due to quenching. Targeting studies in mice bearing breast tumors show strong signaling by pHLIP-FIRE, with a contrast index of ∼17, demonstrating (i) direct imaging of pHLIP insertion and (ii) cargo translocation in vivo. Imaging and targeted cargo delivery should each have clinical applications.

  20. Mono-dispersed high magnetic resonance sensitive magnetite nanocluster probe for detection of nascent tumors by magnetic resonance molecular imaging.

    PubMed

    Zhang, Chunfu; Xie, Xuan; Liang, Sheng; Li, Mingli; Liu, Yajie; Gu, Hongchen

    2012-08-01

    Sensitive molecular imaging and detection of tumors or their supporting neovascularity require high-avidity, target-specific probes, which produce robust signal amplification compatible with a sensitive high-resolution imaging modality. In this context, we fabricated a high magnetic resonance (MR)-sensitive magnetite nanocluster (MNC) probe specific for tumor angiogenesis by assembly of hydrophobic superparamagnetic iron oxide nanoparticles (SPIONs) with (Mal)mPEG-PLA copolymer into cluster and subsequent encoding c(RGDyC) peptide on the cluster (RGD-MNC) for detection of nascent tumors. We found that RGD-MNC is highly sensitive (r(2) = 464.94 s(-1)mM(-1)) and specific for αvβ3-positive cells. Both nascent (35 ± 6.6 mm(3)) and large tumors (256 ± 22.3 mm(3)) can be registered by RGD-MNC and detected by MR imaging (MRI), with the nascent tumors demonstrating more pronounced MR contrast. Immunohistochemical studies revealed that MR signal decrease was closely correlated with histological characteristics of tumors (microvessel density and αvβ3 expression levels) at different growth stages.

  1. Novel B,O-chelated fluorescent probe for nitric oxide imaging in Raw 264.7 macrophages and onion tissues.

    PubMed

    Chen, Jian-Bo; Zhang, Hui-Xian; Guo, Xiao-Feng; Wang, Hong; Zhang, Hua-Shan

    2013-10-24

    A novel fluorescent probe based on B,O-chelated dipyrromethene chromophore in far-visible and near-infrared spectral region (600-900 nm), boron chelated 8-(3,4-diaminophenyl)-3,5-bis(2-hydroxyphenyl)-4-bora-3a,4a-diaza-s-indancene (BOPB), has been first developed for nitric oxide (NO) imaging. BOPB, a turn-on fluorescent probe, can react with NO rapidly under physiological condition. The reaction product of BOPB with NO, BOPB-T, emits bright red fluorescence at 643 nm when excited at 622 nm. Meanwhile, BOPB-T displays high fluorescent quantum yield of 0.21 and good photostability. The selectivity for NO over other reactive oxygen/nitrogen species and ascorbic acid has been investigated and BOPB has good specificity for the detection of NO. MTT assay shows that the toxicity of BOPB (below 10 μM) to living cells can be neglected. Based on these investigations, BOPB has been used for NO imaging in Raw 264.7 cells and onion tissues. Meanwhile, mechanical injury to onion tissues results in a brighter fluorescence around the wound, which indicates that more NO has been produced in plant tissues in response to external stimuli. Our studies illustrate that BOPB has advantages of high sensitivity, low background interference and little photo damage on fluorescence imaging of NO.

  2. Tunable and noncytotoxic PET/SPECT-MRI multimodality imaging probes using colloidally stable ligand-free superparamagnetic iron oxide nanoparticles

    PubMed Central

    Pham, TH Nguyen; Lengkeek, Nigel A; Greguric, Ivan; Kim, Byung J; Pellegrini, Paul A; Bickley, Stephanie A; Tanudji, Marcel R; Jones, Stephen K; Hawkett, Brian S; Pham, Binh TT

    2017-01-01

    Physiologically stable multimodality imaging probes for positron emission tomography/single-photon emission computed tomography (PET/SPECT)-magnetic resonance imaging (MRI) were synthesized using the superparamagnetic maghemite iron oxide (γ-Fe2O3) nanoparticles (SPIONs). The SPIONs were sterically stabilized with a finely tuned mixture of diblock copolymers with either methoxypolyethylene glycol (MPEG) or primary amine NH2 end groups. The radioisotope for PET or SPECT imaging was incorporated with the SPIONs at high temperature. 57Co2+ ions with a long half-life of 270.9 days were used as a model for the radiotracer to study the kinetics of radiolabeling, characterization, and the stability of the radiolabeled SPIONs. Radioactive 67Ga3+ and Cu2+-labeled SPIONs were also produced successfully using the optimized conditions from the 57Co2+-labeling process. No free radioisotopes were detected in the aqueous phase for the radiolabeled SPIONs 1 week after dispersion in phosphate-buffered saline (PBS). All labeled SPIONs were not only well dispersed and stable under physiological conditions but also noncytotoxic in vitro. The ability to design and produce physiologically stable radiolabeled magnetic nanoparticles with a finely controlled number of functionalizable end groups on the SPIONs enables the generation of a desirable and biologically compatible multimodality PET/SPECT-MRI agent on a single T2 contrast MRI probe. PMID:28184160

  3. Live-Cell imaging and measurement of intracellular pH in filamentous fungi using a genetically encoded ratiometric probe.

    PubMed

    Bagar, Tanja; Altenbach, Kirsten; Read, Nick D; Bencina, Mojca

    2009-05-01

    A novel, genetically encoded, ratiometric pH probe (RaVC) was constructed to image and measure intracellular pH in living hyphae of Aspergillus niger. RaVC is a chimeric protein based on the pH-sensitive probe pHluorin, which was partially codon optimized for expression in Aspergillus. Intracellular pH imaging and measurement was performed by simultaneous, dual-excitation confocal ratio imaging. The mean cytoplasmic pH measured was 7.4 to 7.7 based on calibrating RaVC in situ within nigericin-treated hyphae. Pronounced, longitudinal cytoplasmic pH gradients were not observed in the apical 20 microm of actively growing hyphae at the periphery of 18-h-old colonies. The cytoplasmic pH remained unchanged after prolonged growth in buffered medium with pH values between 2.5 or 9.5. Sudden changes in external pH significantly changed cytoplasmic pH by <1.3 pH units, but it returned to its original value within 20 min following treatment. The weak acid and antifungal food preservative sorbic acid caused prolonged, concentration-dependent intracellular acidification. The inhibition of ATPases with N-ethylmaleimide, dicychlohexylcarbodimide, or sodium azide caused the cytoplasmic pH to decrease by <1 pH unit. Treatment with the protonophore carbonyl cyanide m-chlorophenylhydrazone or cyanide p-(trifluoromethoxy) phenylhydrazone reduced the cytoplasmic pH by <1 pH unit. In older hyphae from 32-h-old cultures, RaVC became sequestered within large vacuoles, which were shown to have pH values between 6.2 and 6.5. Overall, our study demonstrates that RaVC is an excellent probe for visualizing and quantifying intracellular pH in living fungal hyphae.

  4. Use of a Novel Rover-mounted Fluorescence Imager and Fluorescent Probes to Detect Biological Material in the Atacama Desert in Daylight

    NASA Technical Reports Server (NTRS)

    Weinstein, S.; Pane, D.; Warren-Rhodes, K.; Cockell, C.; Ernst, L. A.; Minkley, E.; Fisher, G.; Emani, S.; Wettergreen, D. S.; Wagner, M.

    2005-01-01

    We have developed an imaging system, the Fluorescence Imager (FI), for detecting fluorescence signals from sparse microorganisms and biofilms during autonomous rover exploration. The fluorescence signals arise both from naturally occurring chromophores, such as chlorophyll of cyanobacteria and lichens, and from fluorescent probes applied to soil and rocks. Daylight imaging has been accomplished by a novel use of a high-powered flashlamp synchronized to a CCD camera. The fluorescent probes are cell permanent stains that have extremely low intrinsic fluorescence (quantum yields less than 0.01) and a large fluorescence enhancement (quantum yields greater than 0.4) when bound to the target. Each probe specifically targets either carbohydrates, proteins, nucleic acids or membrane lipids, the four classes of macromolecules found in terrestrial life. The intent of the probes is to interrogate the environment for surface and endolithic life forms.

  5. In vivo bacterial imaging without engineering; A novel probe-based strategy facilitated by endogenous nitroreductase enzymes.

    PubMed

    Stanton, Michael; Cronin, Michelle; Lehouritis, Panos; Tangney, Mark

    2015-01-01

    The feasibility of utilising bacteria as vectors for gene therapy is becoming increasingly recognised. This is primarily due to a number of intrinsic properties of bacteria such as their tumour targeting capabilities, their ability to carry large genetic or protein loads and the availability of well-established genetic engineering tools for a range of common lab strains. However, a number of issues relating to the use of bacteria as vectors for gene therapy need to be addressed in order for the field to progress. Amongst these is the need for the development of non-invasive detection/imaging systems for bacteria within a living host. In vivo optical imaging has advanced preclinical research greatly, and typically involves engineering of bacteria with genetic expression constructs for luminescence (e.g. the lux operon) or fluorescent proteins (GFP etc.). This requirement for genetic modification can be restrictive, where engineering is not experimentally appropriate or technologically feasible (e.g. due to lack of suitable engineering tools). We describe a novel strategy exploiting endogenous bacterial enzymatic activity to specifically activate an exogenously administered fluorescent imaging probe. The red shifted, quenched fluorophore CytoCy5S is reduced to a fluorescent form by bacterial-specific nitroreductase (NTR) enzymes. NTR enzymes are present in a wide range of bacterial genera and absent in mammalian systems, permitting highly specific detection of Gram-negative and Gram-positive bacteria in vivo. In this study, dose-responsive bacterial-specific signals were observed in vitro from all genera examined - E. coli, Salmonella, Listeria, Bifidobacterium and Clostridium difficile. Examination of an NTR-knockout strain validated the enzyme specificity of the probe. In vivo whole-body imaging permitted specific, dose-responsive monitoring of bacteria over time in various infection models, and no toxicity to bacteria or host was observed. This study demonstrates

  6. A two-photon fluorescent probe for nitroreductase imaging in living cells, tissues and zebrafish under hypoxia conditions.

    PubMed

    Zhai, Baoping; Hu, Wei; Sun, Jinyu; Chi, Siyu; Lei, Yidi; Zhang, Fang; Zhong, Cheng; Liu, Zhihong

    2017-04-04

    A two-photon fluorescent probe FNTR for nitroreductase was synthesized by using 9,9-dimethyl-2-acetyl-fluoren-7-methylamino (1) as a two-photon fluorophore and a p-nitrobenzyl carbamate group as a recognition domain for nitroreductase (NTR). The probe and the fluorophore were tested under one- and two-photon modes respectively. After reacting with nitroreductase, FNTR had a 130-fold fluorescence enhancement at 563 nm in 10 min and the maximal two-photon action cross-section value was detected as 66 GM at 750 nm. The probe showed a high sensitivity with a detection limit as low as 23.67 ng ml(-1), high selectivity, low cytotoxicity and good photostability. In the presence of reduced nicotinamide adenine dinucleotide (NADH), endogenous NTR was detected in living cells, tissues and zebrafish. Cobalt chloride was used to induce chemical hypoxia to produce NTR, which generated enhanced fluorescence in cells and tumor tissues. Finally, two-photon fluorescence imaging of NTR was achieved in zebrafish at a penetration depth of up to 200 μm.

  7. Low-light imaging system for luminescence probes in living animals

    NASA Astrophysics Data System (ADS)

    Oshiro, Masafumi

    1999-07-01

    The combination of a very high gain image intensifier, a CCD camera and an image processor which eliminates read out noise of the CCD camera, enables one to detect single photon events by photon counting imaging. The detected photons are then counted in the image processor to generate an image. The image intensifier is also designed to minimize dark noise that determines the sensitivity limit. The photon counting imaging system can be used as a standard intensified CCD camera by lowering the gain of the intensifier. This is useful for focusing and getting an image of the entire object in brightfield, which is used as the reference for the luminescent image. This is a very flexible imagin system used to monitor luminescence; such as gene expression, genetically modified luminescent microorganisms, ATP from microorganisms and luminescence from aequorin stimulated by calcium ions. This system also makes it possible to see luminescence generated inside of small animals through their skin without harming them and it is becoming an important tool for In-Vivo monitoring of small animals. In this paper, we discuss recent technique of photon counting imaging.

  8. Development of a high-speed VCSEL OCT system for real-time imaging of conscious patients larynx using a hand-held probe (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Rangarajan, Swathi; Chou, Li-Dek; Coughlan, Carolyn; Sharma, Giriraj; Wong, Brian J. F.; Ramalingam, Tirunelveli S.

    2016-02-01

    Fourier domain optical coherence tomography (FD-OCT) is a noninvasive imaging modality that has previously been used to image the human larynx. However, differences in anatomical geometry and short imaging range of conventional OCT limits its application in a clinical setting. In order to address this issue, we have developed a gradient-index (GRIN) lens rod-based hand-held probe in conjunction with a long imaging range 200 kHz Vertical-Cavity Surface Emitting Lasers (VCSEL) swept-source optical coherence tomography (SS-OCT) system for high speed real-time imaging of the human larynx in an office setting. This hand-held probe is designed to have a long and dynamically tunable working distance to accommodate the differences in anatomical geometry of human test subjects. A nominal working distance (~6 cm) of the probe is selected to have a lateral resolution <100 um within a depth of focus of 6.4 mm, which covers more than half of the 12 mm imaging range of the VCSEL laser. The maximum lateral scanning range of the probe at 6 cm working distance is approximately 8.4 mm, and imaging an area of 8.5 mm by 8.5 mm is accomplished within a second. Using the above system, we will demonstrate real-time cross-sectional OCT imaging of larynx during phonation in vivo in human and ex-vivo in pig vocal folds.

  9. Organic nanostructure-based probes for two-photon imaging of mitochondria and microbes with emission between 430 nm and 640 nm.

    PubMed

    Yang, Xinglong; Wang, Nuoxin; Zhang, Lingmin; Dai, Luru; Shao, Huawu; Jiang, Xingyu

    2017-03-24

    Multi-photon excitation and versatile fluorescent probes are in high need for biological imaging, since one probe can satisfy many needs as a biosensor. Herein we synthesize a series of two-photon excited probes based on tetraphenylethene (TPE) structures (TPE-Acr, TPE-Py, and TPE-Quino), which can image both mammalian cells and bacteria based on aggregation-induced emission (AIE) without washing them. Because of cationic moieties, the fluorescent molecules can aggregate into nanoscale fluorescent organic nanoscale dots to image mitochondria and bacteria with tunable emissions using both one-photon and two-photon excitation. Our research demonstrates that these AIE-dots expand the functions of luminescent organic dots to construct efficient fluorescent sensors applicable to both one-photon and two-photon excitation for bio-imaging of bacteria and mammalian cells.

  10. Back-to-back optical coherence tomography-ultrasound probe for co-registered three-dimensional intravascular imaging with real-time display

    NASA Astrophysics Data System (ADS)

    Li, Jiawen; Ma, Teng; Jing, Joseph; Zhang, Jun; Patel, Pranav M.; Shung, K. Kirk; Zhou, Qifa; Chen, Zhongping

    2014-03-01

    We have developed a novel integrated optical coherence tomography (OCT)-intravascular ultrasound (IVUS) probe, with a 1.5 mm-long rigid-part and 0.9 mm outer diameter, for real-time intracoronary imaging of atherosclerotic plaques and guiding interventional procedures. By placing the OCT ball lens and IVUS 45MHz single element transducer back-to-back at the same axial position, this probe can provide automatically co-registered, co-axial OCT-IVUS imaging. To demonstrate its capability, 3D OCT-IVUS imaging of a pig's coronary artery in real-time displayed in polar coordinates, as well as images of two major types of advanced plaques in human cadaver coronary segments, was obtained using this probe and our upgraded system. Histology validation is also presented.

  11. Parafoveal retinal cone mosaic imaging in children with ultra-compact switchable SLO/OCT handheld probe (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    LaRocca, Francesco; Nankivil, Derek; DuBose, Theodore B.; Toth, Cynthia A.; Farsiu, Sina; Izatt, Joseph A.

    2016-03-01

    In vivo photoreceptor imaging has enhanced the way vision scientists and ophthalmologists understand the retinal structure, function, and etiology of numerous retinal pathologies. However, the complexity and large footprint of current systems capable of resolving photoreceptors has limited imaging to patients who are able to sit in an upright position and fixate for several minutes. Unfortunately, this excludes an important fraction of patients including bedridden patients, small children, and infants. Here, we show that our dual-modality, high-resolution handheld probe with a weight of only 94 g is capable of visualizing photoreceptors in supine children. Our device utilizes a microelectromechanical systems (MEMS) scanner and a novel telescope design to achieve over an order of magnitude reduction in size compared to similar systems. The probe has a 7° field of view and a lateral resolution of 8 µm. The optical coherence tomography (OCT) system has an axial resolution of 7 µm and a sensitivity of 101 dB. High definition scanning laser ophthalmoscopy (SLO) and OCT images were acquired from children ranging from 14 months to 12 years of age with and without pathology during examination under anesthesia in the operating room. Parafoveal cone imaging was shown using the SLO arm of this device without adaptive optics using a 3° FOV for the first time in children under 4 years old. This work lays the foundation for pediatric research, which will improve understanding of retinal development, maldevelopment and early onset of diseases at the cellular level during the beginning stages of human growth.

  12. Optimized Design and Synthesis of Cell Permeable Biarsenical Cyanine Probe for Imaging Tagged Cytosolic Bacterial Proteins

    SciTech Connect

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

    2013-01-21

    To optimize cellular delivery and specific labeling of tagged cytosolic proteins by biarsenical fluorescent probes build around a cyanine dye scaffold, we have systematically varied the polarity of the hydrophobic tails (i.e., 4-5 methylene groups appended by a sulfonate or methoxy ester moiety) and arsenic capping reagent (ethanedithiol versus benzenedithiol). Targeted labeling of the cytosolic proteins SlyD and the alpha subunit of RNA polymerase engineered with a tetracysteine tagging sequences demonstrate the utility of the newly synthesized probes for live-cell visualization, albeit with varying efficiencies and background intensities. Optimal routine labeling and visualization is apparent using the ethanedithiol capping reagent with the uncharged methoxy ester functionalized acyl chains. These measurements demonstrate the general utility of this class of photostable and highly fluorescent biarsenical reagents based on the cyanine scaffold for in vivo targeting of tagged cellular proteins for live cell measurements of protein dynamics.

  13. Complex structural dynamics of nanocatalysts revealed in Operando conditions by correlated imaging and spectroscopy probes

    PubMed Central

    Li, Y.; Zakharov, D.; Zhao, S.; Tappero, R.; Jung, U.; Elsen, A.; Baumann, Ph.; Nuzzo, R.G.; Stach, E.A.; Frenkel, A.I.

    2015-01-01

    Understanding how heterogeneous catalysts change size, shape and structure during chemical reactions is limited by the paucity of methods for studying catalytic ensembles in working state, that is, in operando conditions. Here by a correlated use of synchrotron X-ray absorption spectroscopy and scanning transmission electron microscopy in operando conditions, we quantitatively describe the complex structural dynamics of supported Pt catalysts exhibited during an exemplary catalytic reaction—ethylene hydrogenation. This work exploits a microfabricated catalytic reactor compatible with both probes. The results demonstrate dynamic transformations of the ensemble of Pt clusters that spans a broad size range throughout changing reaction conditions. This method is generalizable to quantitative operando studies of complex systems using a wide variety of X-ray and electron-based experimental probes. PMID:26119246

  14. Complex structural dynamics of nanocatalysts revealed in Operando conditions by correlated imaging and spectroscopy probes

    SciTech Connect

    Li, Y.; Zakharov, D.; Zhao, S.; Tappero, R.; Jung, U.; Elsen, A.; Baumann, Ph.; Nuzzo, R. G.; Stach, E. A.; Frenkel, A. I.

    2015-06-29

    Understanding how heterogeneous catalysts change size, shape and structure during chemical reactions is limited by the paucity of methods for studying catalytic ensembles in working state, that is, in operando conditions. Here by a correlated use of synchrotron X-ray absorption spectroscopy and scanning transmission electron microscopy in operando conditions, we quantitatively describe the complex structural dynamics of supported Pt catalysts exhibited during an exemplary catalytic reaction—ethylene hydrogenation. This work exploits a microfabricated catalytic reactor compatible with both probes. The results demonstrate dynamic transformations of the ensemble of Pt clusters that spans a broad size range throughout changing reaction conditions. Lastly, this method is generalizable to quantitative operando studies of complex systems using a wide variety of X-ray and electron-based experimental probes.

  15. Complex structural dynamics of nanocatalysts revealed in Operando conditions by correlated imaging and spectroscopy probes

    DOE PAGES

    Li, Y.; Zakharov, D.; Zhao, S.; ...

    2015-06-29

    Understanding how heterogeneous catalysts change size, shape and structure during chemical reactions is limited by the paucity of methods for studying catalytic ensembles in working state, that is, in operando conditions. Here by a correlated use of synchrotron X-ray absorption spectroscopy and scanning transmission electron microscopy in operando conditions, we quantitatively describe the complex structural dynamics of supported Pt catalysts exhibited during an exemplary catalytic reaction—ethylene hydrogenation. This work exploits a microfabricated catalytic reactor compatible with both probes. The results demonstrate dynamic transformations of the ensemble of Pt clusters that spans a broad size range throughout changing reaction conditions. Lastly,more » this method is generalizable to quantitative operando studies of complex systems using a wide variety of X-ray and electron-based experimental probes.« less

  16. Complex structural dynamics of nanocatalysts revealed in Operando conditions by correlated imaging and spectroscopy probes

    NASA Astrophysics Data System (ADS)

    Li, Y.; Zakharov, D.; Zhao, S.; Tappero, R.; Jung, U.; Elsen, A.; Baumann, Ph.; Nuzzo, R. G.; Stach, E. A.; Frenkel, A. I.

    2015-06-01

    Understanding how heterogeneous catalysts change size, shape and structure during chemical reactions is limited by the paucity of methods for studying catalytic ensembles in working state, that is, in operando conditions. Here by a correlated use of synchrotron X-ray absorption spectroscopy and scanning transmission electron microscopy in operando conditions, we quantitatively describe the complex structural dynamics of supported Pt catalysts exhibited during an exemplary catalytic reaction--ethylene hydrogenation. This work exploits a microfabricated catalytic reactor compatible with both probes. The results demonstrate dynamic transformations of the ensemble of Pt clusters that spans a broad size range throughout changing reaction conditions. This method is generalizable to quantitative operando studies of complex systems using a wide variety of X-ray and electron-based experimental probes.

  17. Probe classification of on-off type DNA microarray images with a nonlinear matching measure

    NASA Astrophysics Data System (ADS)

    Ryu, Munho; Kim, Jong Dae; Min, Byoung Goo; Kim, Jongwon; Kim, Y. Y.

    2006-01-01

    We propose a nonlinear matching measure, called counting measure, as a signal detection measure that is defined as the number of on pixels in the spot area. It is applied to classify probes for an on-off type DNA microarray, where each probe spot is classified as hybridized or not. The counting measure also incorporates the maximum response search method, where the expected signal is obtained by taking the maximum among the measured responses of the various positions and sizes of the spot template. The counting measure was compared to existing signal detection measures such as the normalized covariance and the median for 2390 patient samples tested on the human papillomavirus (HPV) DNA chip. The counting measure performed the best regardless of whether or not the maximum response search method was used. The experimental results showed that the counting measure combined with the positional search was the most preferable.

  18. Fiber-optic Raman sensing of cell proliferation probes and molecular vibrations: Brain-imaging perspective

    NASA Astrophysics Data System (ADS)

    Doronina-Amitonova, Lyubov V.; Fedotov, Il'ya V.; Ivashkina, Olga I.; Zots, Marina A.; Fedotov, Andrei B.; Anokhin, Konstantin V.; Zheltikov, Aleksei M.

    2012-09-01

    Optical fibers are employed to sense fingerprint molecular vibrations in ex vivo experiments on the whole brain and detect cell proliferation probes in a model study on a quantitatively controlled solution. A specifically adapted spectral filtering procedure is shown to allow the Raman signal from molecular vibrations of interest to be discriminated against the background from the fiber, allowing a highly sensitive Raman detection of the recently demonstrated EdU (5-ethynyl-2'-deoxyuridine) labels of DNA synthesis in cells.

  19. Intravital imaging of mouse colonic adenoma using MMP-based molecular probes with multi-channel fluorescence endoscopy

    PubMed Central

    Oh, Gyungseok; Yoo, Su Woong; Jung, Yebin; Ryu, Yeon-Mi; Park, Youngrong; Kim, Sang-Yeob; Kim, Ki Hean; Kim, Sungjee; Myung, Seung-Jae; Chung, Euiheon

    2014-01-01

    Intravital imaging has provided molecular, cellular and anatomical insight into the study of tumor. Early detection and treatment of gastrointestinal (GI) diseases can be enhanced with specific molecular markers and endoscopic imaging modalities. We present a wide-field multi-channel fluorescence endoscope to screen GI tract for colon cancer using multiple molecular probes targeting matrix metalloproteinases (MMP) conjugated with quantum dots (QD) in AOM/DSS mouse model. MMP9 and MMP14 antibody (Ab)-QD conjugates demonstrate specific binding to colonic adenoma. The average target-to-background (T/B) ratios are 2.10 ± 0.28 and 1.78 ± 0.18 for MMP14 Ab-QD and MMP9 Ab-QD, respectively. The overlap between the two molecular probes is 67.7 ± 8.4%. The presence of false negative indicates that even more number of targeting could increase the sensitivity of overall detection given heterogeneous molecular expression in tumors. Our approach indicates potential for the screening of small or flat lesions that are precancerous. PMID:24877024

  20. A curcumin-based molecular probe for near-infrared fluorescence imaging of tau fibrils in Alzheimer's disease.

    PubMed

    Park, Kwang-Su; Seo, Yujin; Kim, Mi Kyoung; Kim, Kyungdo; Kim, Yun Kyung; Choo, Hyunah; Chong, Youhoon

    2015-12-14

    In recent years, there has been growing interest in the near-infrared (NIR) fluorescence imaging of tau fibrils for the early diagnosis of Alzheimer's disease (AD). In order to develop a curcumin-based NIR fluorescent probe for tau fibrils, structural modification of the curcumin scaffold was attempted by combining the following rationales: the curcumin derivative should preserve its binding affinity to tau fibrils, and, upon binding to tau fibrils, the probe should show favorable fluorescence properties. To meet these requirements, we designed a novel curcumin scaffold with various aromatic substituents. Among the series, the curcumin derivative with a (4-dimethylamino-2,6-dimethoxy)phenyl moiety showed a significant change in its fluorescence properties (22.9-fold increase in quantum yield; Kd, 0.77 μM; λem, 620 nm; Φ, 0.32) after binding to tau fibrils. In addition, fluorescence imaging of tau-green fluorescent protein-transfected SHSY-5Y cells with confirmed that detected tau fibrils in live cells.

  1. Intravital imaging of mouse colonic adenoma using MMP-based molecular probes with multi-channel fluorescence endoscopy.

    PubMed

    Oh, Gyungseok; Yoo, Su Woong; Jung, Yebin; Ryu, Yeon-Mi; Park, Youngrong; Kim, Sang-Yeob; Kim, Ki Hean; Kim, Sungjee; Myung, Seung-Jae; Chung, Euiheon

    2014-05-01

    Intravital imaging has provided molecular, cellular and anatomical insight into the study of tumor. Early detection and treatment of gastrointestinal (GI) diseases can be enhanced with specific molecular markers and endoscopic imaging modalities. We present a wide-field multi-channel fluorescence endoscope to screen GI tract for colon cancer using multiple molecular probes targeting matrix metalloproteinases (MMP) conjugated with quantum dots (QD) in AOM/DSS mouse model. MMP9 and MMP14 antibody (Ab)-QD conjugates demonstrate specific binding to colonic adenoma. The average target-to-background (T/B) ratios are 2.10 ± 0.28 and 1.78 ± 0.18 for MMP14 Ab-QD and MMP9 Ab-QD, respectively. The overlap between the two molecular probes is 67.7 ± 8.4%. The presence of false negative indicates that even more number of targeting could increase the sensitivity of overall detection given heterogeneous molecular expression in tumors. Our approach indicates potential for the screening of small or flat lesions that are precancerous.

  2. In vivo quantifying molecular specificity of Cy5.5-labeled cyclic 9-mer peptide probe with dynamic fluorescence imaging

    PubMed Central

    Dai, Yunpeng; Yin, Jipeng; Huang, Yu; Chen, Xueli; Wang, Guodong; Liu, Yajun; Zhang, Xianghan; Nie, Yongzhan; Wu, Kaichun; Liang, Jimin

    2016-01-01

    We quantified molecular specificity of Cy5.5-GX1 in vivo with dynamic fluorescence imaging to better understand its kinetic properties. According to whether or not free GX1 was injected and when it was injected, twelve of BGC-823 xenografted mice were randomly divided into three groups and underwent a 60 minute dynamic fluorescence scanning. Combined with a principal-component analysis, the binding potential (Bp) of the probe was determined by both Logan graphical analysis with reference tissue model (GARTM) and Lammertsma simplified reference tissue model (SRTM). The sum of the pharmacokinetic rate constants (SKRC) was quantified by the Gurfinkel exponential model (GEXPM). Cy5.5-GX1 specifically targeted tumor both in vitro and in vivo. We obtained similar quantification results of Bp (GARTM Bp = 0.582 ± 0.2655, SRTM Bp = 0.618 ± 0.2923), and obtained a good linear relation between the Bp value and the SKRC value. Our results indicate that the SKRC value is more suitable for an early-stage kinetic data analysis, and the Bp value depicts kinetic characteristics under the equilibrium state. Dynamic fluorescence imaging in conjunction with various kinetic models are optimal tools to quantify molecular specificity of the Cy5.5-GX1 probe in vivo. PMID:27446643

  3. [RovoIving ultrasonic probe for medical endoscope imaging system based on USB2.0].

    PubMed

    Chen, Xiaodong; Wen, Shijie; Yu, Daoyin

    2008-10-01

    This paper mainly introduces the design and implementation of rotary scanning imaging for Endoscopic Ultrasonography System based on USB2.0. The ultrasonic pulse-echo imaging technique has been used. In the paper, we simply introduce the emission circuit, receiving circuit and isolation circuit. According to the character of rotary scanning, we design the synchronous control circuit based on FPGA and data transmission circuit based on USB2.0. Finally the original polar coordinate image is transformed to rectangular coordinate grey image through coordinate transformation. The system performances have been validated by the experimental result gotten by scanning a specific object with continuous rotary motor.

  4. Fiber-Optic Imaging Probe Developed for Space Used to Detect Diabetes Through the Eye

    NASA Technical Reports Server (NTRS)

    Ansari, Rafat R.; Chenault, Michelle V.; Datiles, Manuel B., III; Sebag, J.; Suh, Kwang I.

    2000-01-01

    Approximately 16 million Americans have diabetes mellitus, which can severely impair eyesight by causing cataracts, diabetic retinopathy, and glaucoma. Cataracts are 1.6 times more common in people with diabetes than in those without diabetes, and cataract extraction is the only surgical treatment. In many cases, diabetes-related ocular pathologies go undiagnosed until visual function is compromised. This ongoing pilot project seeks to study the progression of diabetes in a unique animal model by monitoring changes in the lens with a safe, sensitive, dynamic light-scattering probe. Dynamic light scattering (DLS), has the potential to diagnose cataracts at the molecular level. Recently, a new DLS fiber-optic probe was developed at the NASA Glenn Research Center at Lewis Field for noncontact, accurate, and extremely sensitive particle-sizing measurements in fluid dispersions and suspensions (ref. 1). This compact, portable, and rugged probe is free of optical alignment, offers point-and-shoot operation for various online field applications and challenging environments, and yet is extremely flexible in regards to sample container sizes, materials, and shapes. No external vibration isolation and no index matching are required. It can measure particles as small as 1 nm and as large as few micrometers in a wide concentration range from very dilute (waterlike) dispersions to very turbid (milklike) suspensions. It is safe and fast to use, since it only requires very low laser power (10 nW to 3 mW) with very short data acquisition times (2 to 10 sec).

  5. Multicolor probe-based confocal laser endomicroscopy: a new world for in vivo and real-time cellular imaging

    NASA Astrophysics Data System (ADS)

    Vercauteren, Tom; Doussoux, François; Cazaux, Matthieu; Schmid, Guillaume; Linard, Nicolas; Durin, Marie-Amélie; Gharbi, Hédi; Lacombe, François

    2013-03-01

    Since its inception in the field of in vivo imaging, endomicroscopy through optical fiber bundles, or probe-based Confocal Laser Endomicroscopy (pCLE), has extensively proven the benefit of in situ and real-time examination of living tissues at the microscopic scale. By continuously increasing image quality, reducing invasiveness and improving system ergonomics, Mauna Kea Technologies has turned pCLE not only into an irreplaceable research instrument for small animal imaging, but also into an accurate clinical decision making tool with applications as diverse as gastrointestinal endoscopy, pulmonology and urology. The current implementation of pCLE relies on a single fluorescence spectral band making different sources of in vivo information challenging to distinguish. Extending the pCLE approach to multi-color endomicroscopy therefore appears as a natural plan. Coupling simultaneous multi-laser excitation with minimally invasive, microscopic resolution, thin and flexible optics, allows the fusion of complementary and valuable biological information, thus paving the way to a combination of morphological and functional imaging. This paper will detail the architecture of a new system, Cellvizio Dual Band, capable of video rate in vivo and in situ multi-spectral fluorescence imaging with a microscopic resolution. In its standard configuration, the system simultaneously operates at 488 and 660 nm, where it automatically performs the necessary spectral, photometric and geometric calibrations to provide unambiguously co-registered images in real-time. The main hardware and software features, including calibration procedures and sub-micron registration algorithms, will be presented as well as a panorama of its current applications, illustrated with recent results in the field of pre-clinical imaging.

  6. Microfluidic technology platforms for synthesizing, labeling and measuring the kinetics of transport and biochemical reactions for developing molecular imaging probes

    SciTech Connect

    Phelps, Michael E.

    2009-09-01

    Radiotracer techniques are used in environmental sciences, geology, biology and medicine. Radiotracers with Positron Emission Tomography (PET) provided biological examinations of ~3 million patients 2008. Despite the success of positron labeled tracers in many sciences, there is limited access in an affordable and convenient manner to develop and use new tracers. Integrated microfluidic chips are a new technology well matched to the concentrations of tracers. Our goal is to develop microfluidic chips and new synthesis approaches to enable wide dissemination of diverse types of tracers at low cost, and to produce new generations of radiochemists for which there are many unfilled jobs. The program objectives are to: 1. Develop an integrated microfluidic platform technology for synthesizing and 18F-labeling diverse arrays of different classes of molecules. 2. Incorporate microfluidic chips into small PC controlled devices (“Synthesizer”) with a platform interfaced to PC for electronic and fluid input/out control. 3. Establish a de-centralized model with Synthesizers for discovering and producing molecular imaging probes, only requiring delivery of inexpensive [18F]fluoride ion from commercial PET radiopharmacies vs the centralized approach of cyclotron facilities synthesizing and shipping a few different types of 18F-probes. 4. Develop a position sensitive avalanche photo diode (PSAPD) camera for beta particles embedded in a microfluidic chip for imaging and measuring transport and biochemical reaction rates to valid new 18F-labeled probes in an array of cell cultures. These objectives are met within a research and educational program integrating radio-chemistry, synthetic chemistry, biochemistry, engineering and biology in the Crump Institute for Molecular Imaging. The Radiochemistry Training Program exposes PhD and post doctoral students to molecular imaging in vitro in cells and microorganisms in microfluidic chips and in vivo with PET, from new technologies

  7. In Vivo Tracking of Phagocytic Immune Cells Using a Dual Imaging Probe with Gadolinium-Enhanced MRI and Near-Infrared Fluorescence.

    PubMed

    Kim, Eun-Joong; Bhuniya, Sankarprasad; Lee, Hyunseung; Kim, Hyun Min; Shin, Weon Sup; Kim, Jong Seung; Hong, Kwan Soo

    2016-04-27

    A novel dual imaging probe for in vivo magnetic resonance imaging (MRI) and optical imaging was developed by combining gadolinium (Gd)-chelating MR probe and a near-infrared (NIR) fluorophore, aza-BODIPY (AB; BODIPY = boron-dipyrromethene). This aza-BODIPY-based bimodal contrast agent (AB-BCA) showed a significant fluorescence emission around the NIR range and an enhanced longitudinal relaxivity in MR modality. The probe was easily delivered to phagocytic cells of the innate immune system, together with macrophages and dendritic cells (DCs), and presented high-performance fluorescence and MR imaging without obvious cytotoxicity. For in vivo visualization of AB-BCA using MRI and optical imaging, bone marrow-derived DCs were labeled and injected into the footpad of mice, and labeled DCs were tracked in vivo. We observed the migration of AB-BCA-labeled DCs into the lymph nodes via lymphatic vessels using NIR fluorescence and T1-weighted MR images. This dual-modality imaging probe was used for noninvasive monitoring of DC migration into lymph nodes and could be useful for investigating advanced cellular immunotherapy.

  8. Mineral element analysis of carious and sound rat dentin by electron probe microanalyzer combined with back-scattered electron image.

    PubMed

    Tjäderhane, L; Hietala, E L; Larmas, M

    1995-11-01

    We recently demonstrated the advantages of back-scattered electron images (COMPO) in the visualization of dentinal caries, and the relationship of the change in the dentin fluorescence pattern in caries lesions. However, the exact nature of these changes is not known. In this paper, the nature of the changes in the areas with reduced mineral content in COMPO images was investigated. We examined the relation of changes in mineral elements and the appearance of soft carious and sound dentin in COMPO images using a scanning electron microscope (SEM) equipped with an electron probe microanalyzer (EPMA). Rat molars with small dentinal caries lesions just under the DEJ were chosen for the study. The Ca, P, Na, Mg, Zn, F, and total contents were determined by EPMA from five different dentin sites, and the Ca/P and Mg/Ca ratios were calculated. Generally, the lowest contents were found in caries lesions and highest in mantle dentin, with the exceptions of Mg and Zn. The Ca/P ratio was lowest in mantle dentin and highest in carious dentin. The results confirm that the change in fluorescence in the dentinal caries lesion is correlated with the very initial changes in mineral content, and that EPMA used in combination with COMPO images is a useful tool for determining small changes in mineral elements in the carious and adjacent areas of dentin.

  9. Deep tissue volume imaging of birefringence through fibre-optic needle probes for the delineation of breast tumour

    PubMed Central

    Villiger, Martin; Lorenser, Dirk; McLaughlin, Robert A.; Quirk, Bryden C.; Kirk, Rodney W.; Bouma, Brett E.; Sampson, David D.

    2016-01-01

    Identifying tumour margins during breast-conserving surgeries is a persistent challenge. We have previously developed miniature needle probes that could enable intraoperative volume imaging with optical coherence tomography. In many situations, however, scattering contrast alone is insufficient to clearly identify and delineate malignant regions. Additional polarization-sensitive measurements provide the means to assess birefringence, which is elevated in oriented collagen fibres and may offer an intrinsic biomarker to differentiate tumour from benign tissue. Here, we performed polarization-sensitive optical coherence tomography through miniature imaging needles and developed an algorithm to efficiently reconstruct images of the depth-resolved tissue birefringence free of artefacts. First ex vivo imaging of breast tumour samples revealed excellent contrast between lowly birefringent malignant regions, and stromal tissue, which is rich in oriented collagen and exhibits higher birefringence, as confirmed with co-located histology. The ability to clearly differentiate between tumour and uninvolved stroma based on intrinsic contrast could prove decisive for the intraoperative assessment of tumour margins. PMID:27364229

  10. Deep tissue volume imaging of birefringence through fibre-optic needle probes for the delineation of breast tumour

    NASA Astrophysics Data System (ADS)

    Villiger, Martin; Lorenser, Dirk; McLaughlin, Robert A.; Quirk, Bryden C.; Kirk, Rodney W.; Bouma, Brett E.; Sampson, David D.

    2016-07-01

    Identifying tumour margins during breast-conserving surgeries is a persistent challenge. We have previously developed miniature needle probes that could enable intraoperative volume imaging with optical coherence tomography. In many situations, however, scattering contrast alone is insufficient to clearly identify and delineate malignant regions. Additional polarization-sensitive measurements provide the means to assess birefringence, which is elevated in oriented collagen fibres and may offer an intrinsic biomarker to differentiate tumour from benign tissue. Here, we performed polarization-sensitive optical coherence tomography through miniature imaging needles and developed an algorithm to efficiently reconstruct images of the depth-resolved tissue birefringence free of artefacts. First ex vivo imaging of breast tumour samples revealed excellent contrast between lowly birefringent malignant regions, and stromal tissue, which is rich in oriented collagen and exhibits higher birefringence, as confirmed with co-located histology. The ability to clearly differentiate between tumour and uninvolved stroma based on intrinsic contrast could prove decisive for the intraoperative assessment of tumour margins.

  11. Multimodal magnetic resonance imaging: The coordinated use of multiple, mutually informative probes to understand brain structure and function.

    PubMed

    Hao, Xuejun; Xu, Dongrong; Bansal, Ravi; Dong, Zhengchao; Liu, Jun; Wang, Zhishun; Kangarlu, Alayar; Liu, Feng; Duan, Yunsuo; Shova, Satie; Gerber, Andrew J; Peterson, Bradley S

    2013-02-01

    Differing imaging modalities provide unique channels of information to probe differing aspects of the brain's structural or functional organization. In combination, differing modalities provide complementary and mutually informative data about tissue organization that is more than their sum. We acquired and spatially coregistered data in four MRI modalities--anatomical MRI, functional MRI, diffusion tensor imaging (DTI), and magnetic resonance spectroscopy (MRS)--from 20 healthy adults to understand how interindividual variability in measures from one modality account for variability in measures from other modalities at each voxel of the brain. We detected significant correlations of local volumes with the magnitude of functional activation, suggesting that underlying variation in local volumes contributes to individual variability in functional activation. We also detected significant inverse correlations of NAA (a putative measure of neuronal density and viability) with volumes of white matter in the frontal cortex, with DTI-based measures of tissue organization within the superior longitudinal fasciculus, and with the magnitude of functional activation and default-mode activity during simple visual and motor tasks, indicating that substantial variance in local volumes, white matter organization, and functional activation derives from an underlying variability in the number or density of neurons in those regions. Many of these imaging measures correlated with measures of intellectual ability within differing brain tissues and differing neural systems, demonstrating that the neural determinants of intellectual capacity involve numerous and disparate features of brain tissue organization, a conclusion that could be made with confidence only when imaging the same individuals with multiple MRI modalities.

  12. Genetic engineered molecular imaging probes for applications in cell therapy: emphasis on MRI approach

    PubMed Central

    Cho, In K; Wang, Silun; Mao, Hui; Chan, Anthony WS

    2016-01-01

    Recent advances in stem cell-based regenerative medicine, cell replacement therapy, and genome editing technologies (i.e. CRISPR-Cas 9) have sparked great interest in in vivo cell monitoring. Molecular imaging promises a unique approach to noninvasively monitor cellular and molecular phenomena, including cell survival, migration, proliferation, and even differentiation at the whole organismal level. Several imaging modalities and strategies have been explored for monitoring cell grafts in vivo. We begin this review with an introduction describing the progress in stem cell technology, with a perspective toward cell replacement therapy. The importance of molecular imaging in reporting and assessing the status of cell grafts and their relation to the local microenvironment is highlighted since the current knowledge gap is one of the major obstacles in clinical translation of stem cell therapy. Based on currently available imaging techniques, we provide a brief discussion on the pros and cons of each imaging modality used for monitoring cell grafts with particular emphasis on magnetic resonance imaging (MRI) and the reporter gene approach. Finally, we conclude with a comprehensive discussion of future directions of applying molecular imaging in regenerative medicine to emphasize further the importance of correlating cell graft conditions and clinical outcomes to advance regenerative medicine. PMID:27766183

  13. Probing of marker proteins in cancer tissue using quantum dots with Hadamard transform fluorescence imaging microscopy

    NASA Astrophysics Data System (ADS)

    Xu, Hao; Chen, Chuang; Li, Yan; Tang, Hong-Wu

    2009-08-01

    A domestic-made Hadamard transform spectral imaging microscope was employed to provide high-resolutional fluorescence spectrum and image of tiny samples such as single cells and tissues. By using agron laser line at 454 nm to excite fluorescence and based on immunostaining with quantum dots (QDs) at different wavelengths to tag and trace breast cancer biomarkers in human breast cancer tissues, in situ single-color and dual-color fluorescence imaging for human epidermal growth factor receptor 2 (HER2), estrogen receptor (ER) and proliferating cell nuclear antigen (PCNA) in tissues were realized, by using the Hadamard imaging microscope to capture the high S/N ratio fluorescence images. Moreover, through the comparative study of the differences between fluorescence spectra and images of positive samples and negative control, a method was proposed to evaluate tumor malignancy of the specimens based on the analysis of distribution of HER2, ER and PCNA in the tissues. The results show that the Hadamard transform spectral imaging technique can be applied to visualize and quantitatively measure the subcellular molecules inside the tumor tissues and has great potential in biology and medical diagnosis.

  14. Evaluation of 68Ga-Labeled MG7 Antibody: A Targeted Probe for PET/CT Imaging of Gastric Cancer

    PubMed Central

    Xu, Bing; Li, Xiaowei; Yin, Jipeng; Liang, Cong; Liu, Lijuan; Qiu, Zhaoyan; Yao, Liping; Nie, Yongzhan; Wang, Jing; Wu, Kaichun

    2015-01-01

    MG7-Ag, a specific gastric cancer-associated antigen, can be used to non-invasively monitor gastric cancer by molecular imaging with positron emission tomography/computed tomography (PET/CT). In this study, we prepared and evaluated a 68Ga-labeled MG7 antibody as a molecular probe for nanoPET/CT imaging of gastric cancer in a BGC-823 tumor xenografted mouse model. Macrocyclic chelator 1,4,7-triazacyclononane-N,N0,N00-triacetic acid (NOTA)-conjugated MG7 antibody was synthesized and radiolabeled with 68Ga (t1/2 = 67.71 min). Then, 68Ga-NOTA-MG7 was tested using in vitro cytological studies, in vivo nanoPET/CT and Cerenkov imaging studies as well as ex vivo biodistribution and histology studies. The in vitro experiments demonstrated that 68Ga-NOTA-MG7 has an excellent radiolabeling efficiency of approximately 99% without purification, and it is stable in serum after 120 min of incubation. Cell uptake and retention studies confirmed that 68Ga-NOTA-MG7 has good binding affinity and tumor cell retention. For the nanoPET imaging study, the predominant uptake of 68Ga-NOTA-MG7 was visualized in tumor, liver and kidneys. The tumor uptake reached at its peak (2.53 ± 0.28%ID/g) at 60 min pi. Cherenkov imaging also confirmed the specificity of tumor uptake. Moreover, the biodistribution results were consistent with the quantification data of nanoPET/CT imaging. Histologic analysis also demonstrated specific staining of BGC-823 tumor cell lines. PMID:25733152

  15. Probing the potential of neutron imaging for biomedical and biological applications

    SciTech Connect

    Watkin, Kenneth L; Bilheux, Hassina Z; Ankner, John Francis

    2009-01-01

    Neutron imaging of biological specimens began soon after the discovery of the neutron by Chadwick in 1932. The first samples included tumors in tissues, internal organs in rats, and bones. These studies mainly employed thermal neutrons and were often compared with X-ray images of the same or equivalent samples. Although neutron scattering is widely used in biological studies, neutron imaging has yet to be exploited to its full capability in this area. This chapter summarizes past and current research efforts to apply neutron radiography to the study of biological specimens, in the expectation that clinical and medical research, as well as forensic science, may benefit from it.

  16. Probing the Potential of Neutron Imaging for Biomedical and Biological Applications

    NASA Astrophysics Data System (ADS)

    Watkin, K. L.; Bilheux, H. Z.; Ankner, J. F.

    Neutron imaging of biological specimens began soon after the discovery of the neutron by Chadwick in 1932. The first samples included tumors in tissues, internal organs in rats, and bones. These studies mainly employed thermal neutrons and were often compared with X-ray images of the same or equivalent samples. Although neutron scattering is widely used in biological studies, neutron imaging has yet to be exploited to its full capability in this area. This chapter summarizes past and current research efforts to apply neutron radiography to the study of biological specimens, in the expectation that clinical and medical research, as well as forensic science, may benefit from it.

  17. Overcoming the concentration-dependence of responsive probes for magnetic resonance imaging

    PubMed Central

    Ekanger, Levi A.

    2015-01-01

    In magnetic resonance imaging, contrast agents are molecules that increase the contrast-to-noise ratio of non-invasively acquired images. The information gained from magnetic resonance imaging can be increased using responsive contrast agents that undergo chemical changes, and consequently changes to contrast enhancement, for example in response to specific biomarkers that are indicative of diseases. A major limitation with modern responsive contrast agents is concentration-dependence that requires the concentration of contrast agent to be known: an extremely challenging task in vivo. Here, we review advances in several strategies aimed at overcoming the concentration-dependent nature of responsive contrast agents. PMID:25579206

  18. Bioelectromechanical Imaging by Scanning Probe Microscopy: Galvani's Experiment at the Nanoscale

    SciTech Connect

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

    2006-01-01

    Since the discovery in the late 18th century of electrically induced mechanical response in muscle tissue, coupling between electrical and mechanical phenomena has been shown to be a near-universal feature of biological systems. Here, we employ scanning probe microscopy (SPM) to measure the sub-Angstrom mechanical response of a biological system induced by an electric bias applied to a conductive SPM tip. Visualization of the spiral shape and orientation of protein fibrils with 5 nm spatial resolution in a human tooth and chitin molecular bundle orientation in a butterfly wing is demonstrated. In particular, the applicability of SPM-based techniques for the determination of molecular orientation is discussed.

  19. Near-Field Infrared Pump-Probe Imaging of Surface Phonon Coupling in Boron Nitride Nanotubes.

    PubMed

    Gilburd, Leonid; Xu, Xiaoji G; Bando, Yoshio; Golberg, Dmitri; Walker, Gilbert C

    2016-01-21

    Surface phonon modes are lattice vibrational modes of a solid surface. Two common surface modes, called longitudinal and transverse optical modes, exhibit lattice vibration along or perpendicular to the direction of the wave. We report a two-color, infrared pump-infrared probe technique based on scattering type near-field optical microscopy (s-SNOM) to spatially resolve coupling between surface phonon modes. Spatially varying couplings between the longitudinal optical and surface phonon polariton modes of boron nitride nanotubes are observed, and a simple model is proposed.

  20. High Resolution PET Imaging Probe for the Detection, Molecular Characterization, and Treatment Monitoring of Prostate cancer

    DTIC Science & Technology

    2011-07-01

    Nuclear Instruments and Methods in Physics Research A 0168-9002/$ - see front matter & 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.nima...direction along the ring axis is called down-to-up, and the ring plane is spanned by a back-to- front and a left-to-right axes. The probe was placed in the...ring, displaced for 12 cm in back-to- front direction and centrally in all other directions. To estimate sensi- tivity, a barrel ofwaterwith elliptical

  1. Two-Photon Ratiometric Fluorescence Probe with Enhanced Absorption Cross Section for Imaging and Biosensing of Zinc Ions in Hippocampal Tissue and Zebrafish.

    PubMed

    Li, Wanying; Fang, Bingqing; Jin, Ming; Tian, Yang

    2017-02-21

    Zinc ion (Zn(2+)) not only plays an important function in the structural, catalytic, transcription, and regulatory of proteins, but is also an essential ionic signal to regulate brain neurotransmitters pass process. In this work, we designed and synthesized an intramolecular charge transfer-based ratiometric two-photon fluorescence probe, P-Zn, for imaging and biosensing of Zn(2+) in live cell, hippocampal tissue, and zebrafish. The developed probe demonstrated high two-photon absorption cross section (δ) of 516 ± 77 GM, which increased to 958 ± 144 GM after the probe was coordinated with Zn(2+). Furthermore, this P-Zn probe quickly recognized Zn(2+) with high selectivity, over other metal ions, amino acids, and reactive oxygen species. More interestingly, the initial emission peak of the present probe at 465 nm decreased with a new peak increased at 550 nm, leading to the ratiometric determination of Zn(2+) with high accuracy. Finally, this two-photon fluorescence probe with high temporal resolution and remarkable analytical performance, as well as low-cytotoxicity, was successfully applied in imaging of live cells, hippocampal tissues, and zebrafishes. The present P-Zn probe combined with FLIM provided accurate mapping of Zn(2+) distribution at single-cell level. More interestingly, the two-photon spectroscopic results demonstrated that the level of Zn(2+) in hippocampal tissue of mouse with AD was higher than that in normal mouse brain.

  2. Sapphire ball lens-based fiber probe for common-path optical coherence tomography and its applications in corneal and retinal imaging.

    PubMed

    Zhao, Mingtao; Huang, Yong; Kang, Jin U

    2012-12-01

    We describe a common-path swept source optical coherence tomography fiber probe design using a sapphire ball lens for cross-sectional imaging and sensing for retina vitrectomy surgery. The high refractive index (n=1.75) of the sapphire ball lens improves the focusing power and enables the probe to operate in the intraocular space. The highly precise spherical shape of the sapphire lens also reduces astigmatism and coma compared to fused nonspherical ball lenses. A theoretical sensitivity model for common-path optical coherence tomography (CP-OCT) was developed to assess its optimal performance based on an unbalanced photodetector configuration. Two probe designs-with working distances 415 and 1221 μm and lateral resolution 11 and 18 μm-were implemented with sensitivity up to 88 dB, which is significantly higher than previously reported CP-OCT probes. We assessed the performances of the fiber probes by cross-sectional imaging a bovine cornea and retina in air and in vitreous gel with a 1310 nm swept source OCT system. To the best of our knowledge, this is the first demonstration of sapphire ball lens-based CP-OCT probes directly inserted into the vitreous gel of a bovine eyeball for ocular imaging with a sensitivity approaching the theoretical limitation of CP-OCT.

  3. A general strategy for developing cell-permeable photo-modulatable organic fluorescent probes for live-cell super-resolution imaging

    PubMed Central

    Pan, Deng; Hu, Zhe; Qiu, Fengwu; Huang, Zhen-Li; Ma, Yilong; Wang, Yina; Qin, Lingsong; Zhang, Zhihong; Zeng, Shaoqun; Zhang, Yu-Hui

    2014-01-01

    Single-molecule localization microscopy (SMLM) achieves super-resolution imaging beyond the diffraction limit but critically relies on the use of photo-modulatable fluorescent probes. Here we report a general strategy for constructing cell-permeable photo-modulatable organic fluorescent probes for live-cell SMLM by exploiting the remarkable cytosolic delivery ability of a cell-penetrating peptide (rR)3R2. We develop photo-modulatable organic fluorescent probes consisting of a (rR)3R2 peptide coupled to a cell-impermeable organic fluorophore and a recognition unit. Our results indicate that these organic probes are not only cell permeable but can also specifically and directly label endogenous targeted proteins. Using the probes, we obtain super-resolution images of lysosomes and endogenous F-actin under physiological conditions. We resolve the dynamics of F-actin with 10 s temporal resolution in live cells and discern fine F-actin structures with diameters of ~80 nm. These results open up new avenues in the design of fluorescent probes for live-cell super-resolution imaging. PMID:25410769

  4. D38-cholesterol as a Raman active probe for imaging intracellular cholesterol storage

    NASA Astrophysics Data System (ADS)

    Alfonso-García, Alba; Pfisterer, Simon G.; Riezman, Howard; Ikonen, Elina; Potma, Eric O.

    2016-06-01

    We generated a highly deuterated cholesterol analog (D38-cholesterol) and demonstrated its use for selective vibrational imaging of cholesterol storage in mammalian cells. D38-cholesterol produces detectable signals in stimulated Raman scattering (SRS) imaging, is rapidly taken up by cells, and is efficiently metabolized by acyl-CoA cholesterol acyltransferase to form cholesteryl esters. Using hyperspectral SRS imaging of D38-cholesterol, we visualized cholesterol storage in lipid droplets. We found that some lipid droplets accumulated preferentially unesterified D38-cholesterol, whereas others stored D38-cholesteryl esters. In steroidogenic cells, D38-cholesteryl esters and triacylglycerols were partitioned into distinct sets of lipid droplets. Thus, hyperspectral SRS imaging of D38-cholesterol demonstrates a heterogeneous incorporation of neutral lipid species, i.e., free cholesterol, cholesteryl esters, and triacylglycerols, between individual lipid droplets in a cell.

  5. D38-cholesterol as a Raman active probe for imaging intracellular cholesterol storage

    PubMed Central

    Alfonso-García, Alba; Pfisterer, Simon G.; Riezman, Howard; Ikonen, Elina; Potma, Eric O.

    2015-01-01

    Abstract. We generated a highly deuterated cholesterol analog (D38-cholesterol) and demonstrated its use for selective vibrational imaging of cholesterol storage in mammalian cells. D38-cholesterol produces detectable signals in stimulated Raman scattering (SRS) imaging, is rapidly taken up by cells, and is efficiently metabolized by acyl-CoA cholesterol acyltransferase to form cholesteryl esters. Using hyperspectral SRS imaging of D38-cholesterol, we visualized cholesterol storage in lipid droplets. We found that some lipid droplets accumulated preferentially unesterified D38-cholesterol, whereas others stored D38-cholesteryl esters. In steroidogenic cells, D38-cholesteryl esters and triacylglycerols were partitioned into distinct sets of lipid droplets. Thus, hyperspectral SRS imaging of D38-cholesterol demonstrates a heterogeneous incorporation of neutral lipid species, i.e., free cholesterol, cholesteryl esters, and triacylglycerols, between individual lipid droplets in a cell. PMID:26719944

  6. In Vivo Tumor Angiogenesis Imaging Using Peptide-Based Near-Infrared Fluorescent Probes.

    PubMed

    Huang, Rui; Conti, Peter S; Chen, Kai

    2016-01-01

    Near-infrared fluorescence (NIRF) imaging is an emerging imaging technique for studying diseases at the molecular level. Optical imaging with a near-infrared emitting fluorophore for targeting tumor angiogenesis offers a noninvasive method for early tumor detection and efficient monitoring of tumor response to anti-angiogenesis therapy. CD13 receptor, a zinc-dependent membrane-bound ectopeptidase, plays important roles in regulating tumor angiogenesis and the growth of new blood vessels. In this chapter, we use CD13 receptor as an example to demonstrate how to construct CD13-specific NGR-containing peptides via bioorthogonal click chemistry for visualizing and quantifying the CD13 receptor expression in vivo by means of NIRF optical imaging.

  7. Frequency-domain photoacoustic phased array probe for biomedical imaging applications.

    PubMed

    Telenkov, Sergey; Alwi, Rudolf; Mandelis, Andreas; Worthington, Arthur

    2011-12-01

    We report the development of a frequency-domain biomedical photoacoustic imaging system that utilizes a continuous-wave laser source with a custom intensity modulation pattern, ultrasonic phased array for signal detection, and processing coupled with a beam-forming algorithm for reconstruction of photoacoustic correlation images. Sensitivity to optical contrast was demonstrated using tissue-mimicking phantoms and in-vivo tissue samples.

  8. Controlled-Resonant Surface Tapping-Mode Scanning Probe Electrospray Ionization Mass Spectrometry Imaging

    SciTech Connect

    Lorenz, Matthias; Ovchinnikova, Olga S; Kertesz, Vilmos; Van Berkel, Gary J

    2014-01-01

    This paper reports on the advancement of a controlled-resonance surface tapping-mode single capillary liquid junction extraction/ESI emitter for mass spectrometry imaging. The basic instrumental setup and the general operation of the system were discussed and optimized performance metrics were presented. The ability to spot sample, lane scan and chemically image in an automated and controlled fashion were demonstrated. Rapid, automated spot sampling was demonstrated for a variety of compound types including the cationic dye basic blue 7, the oligosaccharide cellopentaose, and the protein equine heart cytochrome c. The system was used for lane scanning and chemical imaging of the cationic dye crystal violet in inked lines on glass and for lipid distributions in mouse brain thin tissue sections. Imaging of the lipids in mouse brain tissue under optimized conditions provided a spatial resolution of approximately 35 m based on the ability to distinguish between features observed both in the optical and mass spectral chemical images. The sampling spatial resolution of this system was comparable to the best resolution that has been reported for other types of atmospheric pressure liquid extraction-based surface sampling/ionization techniques used for mass spectrometry imaging.

  9. In vivo imaging of small animals with optical tomography and near-infrared fluorescent probes

    NASA Astrophysics Data System (ADS)

    Palmer, Matthew R.; Shibata, Yasushi; Kruskal, Jonathan B.; Lenkinski, Robert E.

    2002-06-01

    A developmental optical tomography has been designed for imaging small animals in vivo using near IR fluorophores. The system employs epi-illumination via a 450 W Xe arc lamp, filtered and collimated to illuminate a 10 cm square movable stage. Emission light is filtered then collected by a high- resolution, high quantum efficiency, cooled CCD camera. Stage movement and image acquisition are under the control of a personal computer running system integration and automation software. During an experiment, the anesthetized animal is secured to the stage and up to 200 projections can be acquired over 180 degrees rotation. Angular sampling of the light distribution at a point on the surface is used to determine relative contributions form ballistic and diffuse photons. We have employed the system to investigate a number of applications of in-vivo fluorescent imaging. In dynamic studies, hepatic function has been visualized in nude mice following intravenous injection of indocyanine green (ICG) and cerebrospinal fluid flow as been measured by injection of ICG-lipoprotein conjugate in the subarachnoid space of the lumbar spine followed by dynamic imaging of the brain. Further applications in physiological imaging, cancer detection, and molecular imaging are under investigation in our laboratory.

  10. Multicolor imaging of hydrogen peroxide level in living and apoptotic cells by a single fluorescent probe.

    PubMed

    Wen, Ying; Xue, Fengfeng; Lan, Haichuang; Li, Zhenhua; Xiao, Shuzhang; Yi, Tao

    2017-05-15

    To understand the entangled relationship between reactive oxygen species (ROS) and apoptosis, there is urgent need for simultaneous dynamic monitoring of these two important biological events. In this study, we have developed a fluorescent probe, pep4-NP1, which can simultaneously detect H2O2 and caspase 3, the respective markers of ROS and apoptosis. The probe contains a H2O2 fluorescence reporter (NP1) and Cy5 fluorescent chromophore connected by a caspase 3 specific recognition peptide. The detecting strategy was realized through a controllable fluorescence resonance energy transfer (FRET) process between NP1 and Cy5 of pep4-NP1, after reaction with H2O2, which was verified by molecular calculation and in vitro spectral studies. In the absent of caspase 3, the accumulation of H2O2 induces red fluorescence of pep4-NP1 centered at 663nm in living cells due to the existence of FRET. In contrast, FRET is inhibited in apoptotic cells due to cleavage of the peptide spacer of pep4-NP1 by over-expressed caspase 3. Consequently, green fluorescence (555nm) predominated when labelling production of H2O2 in apoptotic cells. Moreover, Pep4-NP1 shows excellent selectivity towards H2O2 and caspase 3 on their respective reaction sites. Therefore, pep4-NP1 can distinguish endogenously generated H2O2 between living cells and apoptotic cells with different fluorescence wavelengths, providing additional information on the ROS production pathways.

  11. Concise synthesis of a probe molecule enabling analysis and imaging of vizantin.

    PubMed

    Yamamoto, Hirofumi; Oda, Masataka; Nakano, Mayo; Yabiku, Kenta; Shibutani, Masahiro; Nakanishi, Toshiyuki; Suenaga, Midori; Inoue, Masahisa; Imagawa, Hiroshi; Nagahama, Masahiro; Matsunaga, Yoichi; Himeno, Seiichiro; Setsu, Kojun; Sakurai, Jun; Nishizawa, Mugio

    2013-01-01

    Trehalose 6,6'-dicorynomycolate (TDCM) was first characterized in 1963 as a cell surface glycolipid of Corynebacterium spp. by Ioneda and co-workers. TDCM shows potent anti-tumor activity due to its immunoadjuvant properties. Furthermore, the toxicity of TDCM in mice is much weaker than the related trehalose diester of mycolic acid; trehalose 6,6'-dimycolate (TDM, formerly known as cord factor). We have investigated the chemical modification of this class of compound to generate novel agents that display increased immunoadjuvant activity with minimal associated toxicity. During the course of this work we recently developed 6,6'-bis-O-(3-nonyldodecanoyl)-α,α'-trehalose (designated as vizantin). Our results show that vizantin exhibited a potent prophylactic effect on experimental lung metastasis of B16-F0 melanoma cells without a loss of body weight and death in mice. Furthermore, vizantin effectively stimulated human macrophages in an in vitro model, making it a promising candidate for a safe adjuvant in clinical applications. In order to elucidate the pharmacokinetics of vizantin, a probe molecule with similar activity was developed on the basis of a structure-activity relationship (SAR) study with vizantin. The distribution of the probe molecule after intravenous administration into a mouse was assessed by macro confocal microscopy, where it was found to accumulate in the lungs and liver.

  12. Biocompatible photoresistant far-red emitting, fluorescent polymer probes, with near-infrared two-photon absorption, for living cell and zebrafish embryo imaging.

    PubMed

    Adjili, Salim; Favier, Arnaud; Fargier, Guillaume; Thomas, Audrey; Massin, Julien; Monier, Karine; Favard, Cyril; Vanbelle, Christophe; Bruneau, Sylvia; Peyriéras, Nadine; Andraud, Chantal; Muriaux, Delphine; Charreyre, Marie-Thérèse

    2015-04-01

    Exogenous probes with far-red or near-infrared (NIR) two-photon absorption and fluorescence emission are highly desirable for deep tissue imaging while limiting autofluorescence. However, molecular probes exhibiting such properties are often hydrophobic. As an attractive alternative, we synthesized water-soluble polymer probes carrying multiple far-red fluorophores and demonstrated here their potential for live cell and zebrafish embryo imaging. First, at concentrations up to 10 μm, these polymer probes were not cytotoxic. They could efficiently label living HeLa cells, T lymphocytes and neurons at an optimal concentration of 0.5 μm. Moreover, they exhibited a high resistance to photobleaching in usual microscopy conditions. In addition, these polymer probes could be successfully used for in toto labeling and in vivo two-photon microscopy imaging of developing zebrafish embryos, with remarkable properties in terms of biocompatibility, internalization, diffusion, stability and wavelength emission range. The near-infrared two-photon absorption peak at 910 nm is particularly interesting since it does not excite the zebrafish endogenous fluorescence and is likely to enable long-term time-lapse imaging with limited photodamage.

  13. Development of Molecular Probes Based on Iron Oxide Nanoparticles for in Vivo Magnetic Resonance/Photoacoustic Dual Imaging of Target Molecules in Tumors.

    PubMed

    Sano, Kohei

    2017-01-01

     Molecular imaging probes that enable seamless diagnoses of tumors in the preoperative and intraoperative stages could lead to surgical resection of tumors based on highly accurate diagnoses. Because iron oxide nanoparticles (IONPs) have high proton relaxivity and high molar extinction coefficients suitable for magnetic resonance imaging (MRI) and photoacoustic imaging, respectively, we planned to develop molecular imaging probes applicable to the pre- (MRI) and intraoperative (photoacoustic imaging) stages. Human epidermal growth factor receptor 2 (EGFR2; HER2) was selected as a target molecule, and we designed IONPs (20, 50, and 100 nm) conjugated with anti-HER2 moieties [whole IgG (trastuzumab), single-chain fragment variable (scFv), and peptide] for HER2-targeted tumor imaging. Among the probes tested, scFv-conjugated IONPs (scFv-IONPs) (20 nm) exhibited the highest binding affinity to HER2 (Kd=0.01 nM). An in vivo biodistribution study using (111)In-labeled probes demonstrated that more scFv-IONPs (20 nm) accumulated in HER2-positive than in HER2-negative tumors, suggesting that the uptake of scFv-IONPs is HER2 specific. The scFv-IONPs (20 nm) showed high proton relaxivity and a probe concentration-dependent photoacoustic signal. In vivo MR/photoacoustic imaging studies using scFv-IONPs (20 nm) facilitated HER2-specific visualization of tumors. Furthermore, an iron-staining study demonstrated that the uptake of scFv-IONPs was notable only in HER2-positive tumors. These results suggest that scFv-IONPs (20 nm) may be useful for MR/photoacoustic dual imaging, which could achieve seamless diagnoses in the preoperative and intraoperative stages.

  14. Brain redox imaging in the pentylenetetrazole (PTZ)-induced kindling model of epilepsy by using in vivo electron paramagnetic resonance and a nitroxide imaging probe.

    PubMed

    Emoto, Miho C; Yamato, Mayumi; Sato-Akaba, Hideo; Yamada, Ken-ichi; Fujii, Hirotada G

    2015-11-03

    Much evidence supports the idea that oxidative stress is involved in the pathogenesis of epilepsy, and therapeutic interventions with antioxidants are expected as adjunct antiepileptic therapy. The aims of this study were to non-invasively obtain spatially resolved redox data from control and pentylenetetrazole (PTZ)-induced kindled mouse brains by electron paramagnetic resonance (EPR) imaging and to visualize the brain regions that are sensitive to oxidative damage. After infusion of the redox-sensitive imaging probe 3-methoxycarbonyl-2,2,5,5-tetramethyl-piperidine-1-oxyl (MCP), a series of EPR images of PTZ-induced mouse heads were measured. Based on the pharmacokinetics of the reduction reaction of MCP in the mouse heads, the pixel-based rate constant of its reduction reaction was calculated as an index of redox status in vivo and mapped as a redox map. The obtained redox map showed heterogeneity in the redox status in PTZ-induced mouse brains compared with control. The co-registered image of the redox map and magnetic resonance imaging (MRI) for both control and PTZ-induced mice showed a clear change in the redox status around the hippocampus after PTZ. To examine the role of antioxidants on the brain redox status, the levels of antioxidants were measured in brain tissues of control and PTZ-induced mice. Significantly lower concentrations of glutathione in the hippocampus of PTZ-kindled mice were detected compared with control. From the results of both EPR imaging and the biochemical assay, the hippocampus was found to be susceptible to oxidative damage in the PTZ-induced animal model of epilepsy.

  15. Metal nanoparticle fluorophore: a powerful fluorescence probe in single cell imaging

    NASA Astrophysics Data System (ADS)

    Zhang, Jian; Fu, Yi; Zhao, Richard Y.; Lakowicz, Joseph R.

    2010-02-01

    Metal nanoparticle fluorophores have been developed using metal-enhanced fluorescence (MEF) principle. Compared with the conventional organic fluorophores, the metal fluorophores display the increasing brightness and shortening lifetime as well as the lengthening photostability and reducing photoblinking. Conjugated the metal fluorophores on the surfaces of cell lines, the cell images were recorded on a scanning confocal microscopy in the either emission intensity or lifetime. The emission spots by the conjugated metal fluorophores were isolated distinctly from the cell images because of their brighter signals and shorter lifetimes. Collected in the three-dimension, the total number of emission signals could be counted quantitatively and the distribution could be described on the cell surfaces. It was noticed that the emission intensity over the cell image was increased with an increase of the number of metal fluorophore on the cell surface and simultaneously the lifetime was altered. A quantitative regression curve was achieved between the amount of metal fluorophore on the cell surface and the emission intensity or lifetime over the entire cell image. Based on this regression curve, the target molecules on the cell surfaces could be quantified readily through the cell intensity and/or lifetime at the single cell level instead of the direct count to the emission spots. As novel molecule imaging agents, these metal fluorophores are being applied in the quantification and distribution of target molecule on the cell surface for the clinical diagnostic research.

  16. MEMS-based handheld scanning probe with pre-shaped input signals for distortion-free images in Gabor-domain optical coherence microscopy.

    PubMed

    Cogliati, Andrea; Canavesi, Cristina; Hayes, Adam; Tankam, Patrice; Duma, Virgil-Florin; Santhanam, Anand; Thompson, Kevin P; Rolland, Jannick P

    2016-06-13

    High-speed scanning in optical coherence tomography (OCT) often comes with either compromises in image quality, the requirement for post-processing of the acquired images, or both. We report on distortion-free OCT volumetric imaging with a dual-axis micro-electro-mechanical system (MEMS)-based handheld imaging probe. In the context of an imaging probe with optics located between the 2D MEMS and the sample, we report in this paper on how pre-shaped open-loop input signals with tailored non-linear parts were implemented in a custom control board and, unlike the sinusoidal signals typically used for MEMS, achieved real-time distortion-free imaging without post-processing. The MEMS mirror was integrated into a compact, lightweight handheld probe. The MEMS scanner achieved a 12-fold reduction in volume and 17-fold reduction in weight over a previous dual-mirror galvanometer-based scanner. Distortion-free imaging with no post-processing with a Gabor-domain optical coherence microscope (GD-OCM) with 2 μm axial and lateral resolutions over a field of view of 1 × 1 mm2 is demonstrated experimentally through volumetric images of a regular microscopic structure, an excised human cornea, and in vivo human skin.

  17. Clinically-translated silica nanoparticles as dual-modality cancer-targeted probes for image-guided surgery and interventions

    PubMed Central

    Phillips, Evan; Montero, Pablo H.; Cheal, Sarah M.; Stambuk, Hilda; Durack, Jeremy C.; Sofocleous, Constantinos T.; Meester, Richard J. C.; Wiesner, Ulrich; Patel, Snehal

    2015-01-01

    Early diagnosis and treatment of melanoma are essential to minimizing morbidity and mortality. The presence of lymph node metastases is a vital prognostic predictor, and accurate identification by imaging has important implications for disease staging, prognosis, and clinical outcome. Sentinel lymph node (SLN) mapping procedures are limited by a lack of intraoperative visualization tools that can aid accurate determination of disease spread and delineate nodes from adjacent critical neural and vascular structures. Newer methods for circumventing these issues can exploit a variety of imaging tools, including biocompatible particle-based platforms coupled with portable device technologies for use with image-guided surgical and interventional procedures. We describe herein a clinically-translated, integrin-targeting platform for use with both PET and optical imaging that meets a number of key design criteria for improving SLN tissue localization and retention, target-to-background ratios, and clearance from the site of injection and the body. The use of such agents for selectively probing critical cancer targets may elucidate important insights into cellular and molecular processes that govern metastatic disease spread. Coupled with portable, real-time optical camera systems, we show that pre-operative PET imaging findings for mapping metastatic disease in clinically-relevant larger-animal models can be readily translated into the intraoperative setting for direct visualization of the draining tumor lymphatics and fluorescent SLN/s with histologic correlation. The specificity of this platform, relative to the standard-of-care radiotracer, 18F-FDG, for potentially discriminating metastatic disease from inflammatory processes is also discussed in the setting of surgically-based or interventionally-driven therapies. PMID:23138852

  18. Fluorescence-Guided Probes of Aptamer-Targeted Gold Nanoparticles with Computed Tomography Imaging Accesses for in Vivo Tumor Resection

    PubMed Central

    Li, Cheng-Hung; Kuo, Tsung-Rong; Su, Hsin-Jan; Lai, Wei-Yun; Yang, Pan-Chyr; Chen, Jinn-Shiun; Wang, Di-Yan; Wu, Yi-Chun; Chen, Chia-Chun

    2015-01-01

    Recent development of molecular imaging probes for fluorescence-guided surgery has shown great progresses for determining tumor margin to execute the tissue resection. Here we synthesize the fluorescent gold nanoparticles conjugated with diatrizoic acid and nucleolin-targeted AS1411 aptamer. The nanoparticle conjugates exhibit high water-solubility, good biocompatibility, visible fluorescence and strong X-ray attenuation for computed tomography (CT) contrast enhancement. The fluorescent nanoparticle conjugates are applied as a molecular contrast agent to reveal the tumor location in CL1-5 tumor-bearing mice by CT imaging. Furthermore, the orange-red fluorescence emitting from the conjugates in the CL1-5 tumor can be easily visualized by the naked eyes. After the resection, the IVIS measurements show that the fluorescence signal of the nanoparticle conjugates in the tumor is greatly enhanced in comparison to that in the controlled experiment. Our work has shown potential application of functionalized nanoparticles as a dual-function imaging agent in clinical fluorescence-guided surgery. PMID:26507179

  19. A Novel Water-Soluble Fluorescence Probe with Wash-Free Cellular Imaging Capacity Based on AIE Characteristics.

    PubMed

    Qian, Yunxia; Liu, Hongmei; Tan, Haijian; Yang, Qingmin; Zhang, Shuchen; Han, Lingui; Yi, Xuegang; Huo, Li; Zhao, Hongchi; Wu, Yonggang; Bai, Libin; Ba, Xinwu

    2017-03-21

    A potential real-time imaging water-soluble fluorescent polymer (P3) is facilely prepared via one-pot method. For P3, tetraphenylethene unit serves as the fluorescent unit, poly(acryloyl ethylene diamine) (a kind of polyelectrolyte) with specific degree of polymerization acts as water-soluble part. (1) H-NMR, gel permeation chromatography (GPC), UV-vis spectroscopy, photoluminescence (PL), and confocal laser scanning microscopy are undertaken to characterize the structure and property of P3. The results of wash-free cellular imaging show that the signal-to-noise ratio is high as the concentration of P3 is 50 μg mL(-1) . In addition, the pH-responsive and Cd(2+) -responsive are also investigated in this paper. The results coming from pH-responsive show that P3 solution displays significant fluorescence under near neutral. And the result from the cellular imaging shows that intracellular fluorescence intensity enhances with the augment of concentration of Cd(2+) , which reveals that P3 can give a hint to resolve the dilemma of traditional fluorescent dyes used as living cellular fluorescent probe.

  20. In vivo imaging of neuronal activity by targeted expression of a genetically encoded probe in the mouse.

    PubMed

    Bozza, Thomas; McGann, John P; Mombaerts, Peter; Wachowiak, Matt

    2004-04-08

    Genetically encoded probes show great promise in permitting functional imaging of specified neuronal populations in the intact nervous system, yet their in vivo application has been limited. Here, we have targeted expression of synapto-pHluorin, a pH-sensitive protein that reports synaptic vesicle fusion, to olfactory sensory neurons in mouse. Synapto-pHluorin selectively labeled presynaptic terminals of sensory neurons in glomeruli of the olfactory bulb. Odorant stimulation evoked large-amplitude fluorescence increases that were localized to individual glomeruli in vivo, correlated with presynaptic calcium influx, graded with stimulus intensity, and stable over a period of days. Spatial patterns of odorant-activated glomeruli were distributed and did not change systematically with increasing carbon chain length, in contrast to the finely organized chemotopy that has been reported using other imaging methods. Targeted expression of synapto-pHluorin in mouse will permit the analysis of previously inaccessible neuronal populations and chronic imaging from genetically identified neurons in vivo.

  1. In vivo optical imaging of human vaginal gel thickness distributions with a probe-based, dual-modality instrument

    NASA Astrophysics Data System (ADS)

    Drake, Tyler K.; DeSoto, Michael G.; Peters, Jennifer J.; Henderson, Marcus H.; Thiele, Bonnie; Bishop, Tammy Sinclair; Murtha, Amy P.; Katz, David F.; Wax, Adam

    2012-11-01

    We used a probe-based dual-modality optical imaging instrument to measure in vivo coating thickness distributions of a gel distributed along the vaginal lumen, in a clinical study. The gel was a surrogate for one delivering an anti-HIV topical microbicide. Imaging data from Fourier-domain multiplexed low-coherence interferometry (mLCI) and fluorimetric measurements were compared to assess the feasibility and accuracy of mLCI in measuring in vivo gel coating thickness distributions. In each study session, 3.5 mL of Replens gel was inserted to the vaginal fornix while the participant was supine. The participant either: 1. remained supine (10 or 60 min) or 2. sat up (1 min), stood up (1 min), sat down (1 min) and returned to the supine position; net elapsed time was 10 or 60 min after which the gel distribution was imaged. Local coating thickness distributions were qualitatively and quantitatively similar. Here mLCI did not accurately measure thicker gel coatings (>0.8 mm), a limitation not seen with fluorimetry. However, mLCI is capable of measuring in vivo microbicide gel distributions with resolution on the order of 10 μm, without the need for exogenous contrast agents, and can accurately capture relevant summary coating measures in good agreement with fluorimetry.

  2. Two-dimensional nanoscale imaging of gadolinium spins via scanning probe relaxometry with a single spin in diamond

    NASA Astrophysics Data System (ADS)

    Pelliccione, Matthew; Myers, Bryan; Pascal, Laetitia; Das, Anand; Jayich, Ania

    2015-03-01

    Spin-labeling of molecules with paramagnetic ions is an important approach for determining molecular structure, however current ensemble techniques lack the sensitivity to detect few isolated spins. In this talk, we demonstrate two-dimensional nanoscale imaging of paramagnetic gadolinium compounds using scanning relaxometry of a single nitrogen vacancy (NV) center in diamond. Gadopentetate dimeglumine attached to an atomic force microscope tip is controllably interacted with and detected by the NV center, by virtue of the fact that the NV exhibits fast relaxation in the fluctuating magnetic field generated by electron spin flips in the gadolinium. We demonstrate a reduction in the T1 relaxation time of the NV center by over two orders of magnitude, probed with a spatial resolution of 20 nm, limited by thermal drift in ambient conditions. We discuss the importance of mitigating drift to reach truly nanoscale imaging and present progress towards cryogenic scanning magnetometry, along with utilizing chemically functionalized tips to gain greater control over the Gd distribution on the tip. Our result exhibits the viability of the technique for imaging individual spins attached to complex nanostructures or biomolecules, along with studying the magnetic dynamics of isolated spins.

  3. Simultaneous hydrogen and heavier element isotopic ratio images with a scanning submicron ion probe and mass resolved polyatomic ions.

    PubMed

    Slodzian, Georges; Wu, Ting-Di; Bardin, Noémie; Duprat, Jean; Engrand, Cécile; Guerquin-Kern, Jean-Luc

    2014-04-01

    In situ microanalysis of solid samples is often performed using secondary ion mass spectrometry (SIMS) with a submicron ion probe. The destructive nature of the method makes it mandatory to prevent information loss by using instruments combining efficient collection of secondary ions and a mass spectrometer with parallel detection capabilities. The NanoSIMS meets those requirements with a magnetic spectrometer but its mass selectivity has to be improved for accessing opportunities expected from polyatomic secondary ions. We show here that it is possible to perform D/H ratio measurement images using 12CD-/12CH-, 16OD-/16OH-, or 12C2D-/12C2H- ratios. These polyatomic species allow simultaneous recording of D/H ratios and isotopic compositions of heavier elements like 15N/14N (via 12C15N-/12C14N-) and they provide a powerful tool to select the phase of interest (e.g., mineral versus organics). We present high mass resolution spectra and an example of isotopic imaging where D/H ratios were obtained via the 12C2D-/12C2H- ratio with 12C2D- free from neighboring mass interferences. Using an advanced mass resolution protocol, a "conventional" mass resolving power of 25,000 can be achieved. Those results open many perspectives for isotopic imaging at a fine scale in biology, material science, geochemistry, and cosmochemistry.

  4. Development of novel fluorescent probe 3-perylene diphenylphosphine for determination of lipid hydroperoxide with fluorescent image analysis

    SciTech Connect

    Chotimarkorn, Chatchawan; Nagasaka, Reiko; Ushio, Hideki . E-mail: hushio@s.kaiyodai.ac.jp; Ohshima, Toshiaki; Matsunaga, Shigeki

    2005-12-16

    A novel fluorescent probe 3-perylene diphenylphosphine (3-PeDPP) was synthesized for the direct analysis of lipid hydroperoxides. The structure of 3-PeDPP was identified by the spectroscopic data, FAB-MS, {sup 1}H NMR, and {sup 13}C NMR. The reactivities of 3-PeDPP with lipid hydroperoxides were investigated in chloroform/MeOH homogeneous solutions and PC liposome model systems oxidized by either 2,2'-azobis(2-amidinopropane)dihydrochloride and photosensitized oxidation. The fluorescence intensity derived from 3-perylene diphenylphosphineoxide (3-PeDPPO) increased proportionally with amount of hydroperoxides produced in homogeneous solutions and liposome model systems. 3-PeDPP was easily incorporated into mouse myeloma SP2 cells and thin tissue section for dynamic membrane lipid peroxidation studies. Linear correlations between fluorescence intensity and amount of hydroperoxides in the cell membrane and tissue sections were obtained. The fluorescence intensity from 2-dimensional image analysis was also well correlated with lipid hydroperoxide level in these models. Thus, the novel probe 3-PeDPP is useful for the direct determination of lipid hydroperoxides in biological materials.

  5. Fluorescent amino acid undergoing excited state intramolecular proton transfer for site-specific probing and imaging of peptide interactions.

    PubMed

    Sholokh, Marianna; Zamotaiev, Oleksandr M; Das, Ranjan; Postupalenko, Viktoriia Y; Richert, Ludovic; Dujardin, Denis; Zaporozhets, Olga A; Pivovarenko, Vasyl G; Klymchenko, Andrey S; Mély, Yves

    2015-02-12

    Fluorescent amino acids bearing environment-sensitive fluorophores are highly valuable tools for site-selective probing of peptide/ligand interactions. Herein, we synthesized a fluorescent l-amino acid bearing the 4'-methoxy-3-hydroxyflavone fluorophore (M3HFaa) that shows dual emission, as a result of an excited state intramolecular proton transfer (ESIPT). The dual emission of M3HFaa was found to be substantially more sensitive to hydration as compared to previous analogues. By replacing the Ala30 and Trp37 residues of a HIV-1 nucleocapsid peptide, M3HFaa was observed to preserve the peptide structure and functions. Interaction of the labeled peptides with nucleic acids and lipid vesicles produced a strong switch in their dual emission, favoring the emission of the ESIPT product. This switch was associated with the appearance of long-lived fluorescence lifetimes for the ESIPT product, as a consequence of the rigid environment in the complexes that restricted the relative motions of the M3HFaa aromatic moieties. The strongest restriction and thus the longest fluorescence lifetimes were observed at position 37 in complexes with nucleic acids, where the probe likely stacks with the nucleobases. Based on the dependence of the lifetime values on the nature of the ligand and the labeled position, two-photon fluorescence lifetime imaging was used to identify the binding partners of the labeled peptides microinjected into living cells. Thus, M3HFaa appears as a sensitive tool for monitoring site selectively peptide interactions in solution and living cells.

  6. Indole-based cyanine as a nuclear RNA-selective two-photon fluorescent probe for live cell imaging.

    PubMed

    Guo, Lei; Chan, Miu Shan; Xu, Di; Tam, Dick Yan; Bolze, Frédéric; Lo, Pik Kwan; Wong, Man Shing

    2015-05-15

    We have demonstrated that the subcellular targeting properties of the indole-based cyanines can be tuned by the functional substituent attached onto the indole moiety in which the first example of a highly RNA-selective and two-photon active fluorescent light-up probe for high contrast and brightness TPEF images of rRNA in the nucleolus of live cells has been developed. It is important to find that this cyanine binds much stronger toward RNA than DNA in a buffer solution as well as selectively stains and targets to rRNA in the nucleolus. Remarkably, the TPEF brightness (Φσmax) is dramatically increased with 11-fold enhancement in the presence of rRNA, leading to the record high Φσmax of 228 GM for RNA. This probe not only shows good biocompatibility and superior photostability but also offers general applicability to various live cell lines including HeLa, HepG2, MCF-7, and KB cells and excellent counterstaining compatibility with commercially available DNA or protein trackers.

  7. Phenylboronic acid-based (19)F MRI probe for the detection and imaging of hydrogen peroxide utilizing its large chemical-shift change.

    PubMed

    Nonaka, Hiroshi; An, Qi; Sugihara, Fuminori; Doura, Tomohiro; Tsuchiya, Akira; Yoshioka, Yoshichika; Sando, Shinsuke

    2015-01-01

    Herein, we report on a new (19)F MRI probe for the detection and imaging of H2O2. Our designed 2-fluorophenylboronic acid-based (19)F probe promptly reacted with H2O2 to produce 2-fluorophenol via boronic acid oxidation. The accompanying (19)F chemical-shift change reached 31 ppm under our experimental conditions. Such a large chemical-shift change allowed for the imaging of H2O2 by (19)F chemical-shift-selective MRI.

  8. Three-dimensional chemical imaging of embedded nanoparticles using atom probe tomography.

    PubMed

    Kuchibhatla, Satyanarayana V N T; Shutthanandan, V; Prosa, T J; Adusumilli, P; Arey, B; Buxbaum, A; Wang, Y C; Tessner, T; Ulfig, R; Wang, C M; Thevuthasan, S

    2012-06-01

    Analysis of nanoparticles is often challenging especially when they are embedded in a matrix. Hence, we have used laser-assisted atom probe tomography (APT) to analyze the Au nanoclusters synthesized in situ using ion-beam implantation in a single crystal MgO matrix. APT analysis along with scanning transmission electron microscopy and energy dispersive spectroscopy (STEM-EDX) indicated that the nanoparticles have an average size ~8-12 nm. While it is difficult to analyze the composition of individual nanoparticles using STEM, APT analysis can give three-dimensional compositions of the same. It was shown that the maximum Au concentration in the nanoparticles increases with increasing particle size, with a maximum Au concentration of up to 50%.

  9. Imaging of arsenic Cottrell atmospheres around silicon defects by three-dimensional atom probe tomography.

    PubMed

    Thompson, Keith; Flaitz, Philip L; Ronsheim, Paul; Larson, David J; Kelly, Thomas F

    2007-09-07

    Discrete control of individual dopant or impurity atoms is critical to the electrical characteristics and fabrication of silicon nanodevices. The unavoidable introduction of defects into silicon during the implantation process may prevent the uniform distribution of dopant atoms. Cottrell atmospheres are one such nonuniformity and occur when interstitial atoms interact with dislocations, pinning the dislocation and trapping the interstitial. Atom probe tomography has been used to quantify the location and elemental identity of the atoms proximate to defects in silicon. We found that Cottrell atmospheres of arsenic atoms form around defects after ion implantation and annealing. Furthermore, these atmospheres persist in surrounding dislocation loops even after considerable thermal treatment. If not properly accommodated, these atmospheres create dopant fluctuations that ultimately limit the scalability of silicon devices.

  10. A "distorted-BODIPY"-based fluorescent probe for imaging of cellular viscosity in live cells.

    PubMed

    Zhu, Hao; Fan, Jiangli; Li, Miao; Cao, Jianfang; Wang, Jingyun; Peng, Xiaojun

    2014-04-14

    Cellular viscosity is a critical factor in governing diffusion-mediated cellular processes and is linked to a number of diseases and pathologies. Fluorescent molecular rotors (FMRs) have recently been developed to determine viscosity in solutions or biological fluid. Herein, we report a "distorted-BODIPY"-based probe BV-1 for cellular viscosity, which is different from the conventional "pure rotors". In BV-1, the internal steric hindrance between the meso-CHO group and the 1,7-dimethyl group forced the boron-dipyrrin framework to be distorted, which mainly caused nonradiative deactivation in low-viscosity environment. BV-1 gave high sensitivity (x=0.62) together with stringent selectivity to viscosity, thus enabling viscosity mapping in live cells. Significantly, the increase of cytoplasmic viscosity during apoptosis was observed by BV-1 in real time.

  11. An optimized algorithm of image stitching in the case of a multi-modal probe for monitoring the evolution of scars

    NASA Astrophysics Data System (ADS)

    Kassab, R.; Treuillet, S.; Marzani, F.; Pieralli, C.; Lapayre, J. C.

    2013-03-01

    We propose a new system that makes possible to monitor the evolution of scars after the excision of a tumorous dermatosis. The hardware part of this system is composed of a new optical innovative probe with which two types of images can be acquired simultaneously: an anatomic image acquired under a white light and a functional one based on autofluorescence from the protoporphyrin within the cancer cells. For technical reasons related to the maximum size of the area covered by the probe, acquired images are too small to cover the whole scar. That is why a sequence of overlapping images is taken in order to cover the required area. The main goal of this paper is to describe the creation of two panoramic images (anatomic and functional). Fluorescence images do not have enough salient information for matching the images; stitching algorithms are applied over each couple of successive white light images to produce an anatomic panorama of the entire scar. The same transformations obtained from this step are used to register and stitch the functional images. Several experiments have been implemented using different stitching algorithms (SIFT, ASIFT and SURF), with various transformation parameters (angles of rotation,