Lipid nanotube or nanowire sensor

DOEpatents

Noy, Aleksandr [Belmont, CA; Bakajin, Olgica [San Leandro, CA; Letant, Sonia [Livermore, CA; Stadermann, Michael [Dublin, CA; Artyukhin, Alexander B [Menlo Park, CA

2009-06-09

A sensor apparatus comprising a nanotube or nanowire, a lipid bilayer around the nanotube or nanowire, and a sensing element connected to the lipid bilayer. Also a biosensor apparatus comprising a gate electrode; a source electrode; a drain electrode; a nanotube or nanowire operatively connected to the gate electrode, the source electrode, and the drain electrode; a lipid bilayer around the nanotube or nanowire, and a sensing element connected to the lipid bilayer.

Lipid nanotube or nanowire sensor

DOEpatents

Noy, Aleksandr [Belmont, CA; Bakajin, Olgica [San Leandro, CA; Letant, Sonia [Livermore, CA; Stadermann, Michael [Dublin, CA; Artyukhin, Alexander B [Menlo Park, CA

2010-06-29

A sensor apparatus comprising a nanotube or nanowire, a lipid bilayer around the nanotube or nanowire, and a sensing element connected to the lipid bilayer. Also a biosensor apparatus comprising a gate electrode; a source electrode; a drain electrode; a nanotube or nanowire operatively connected to the gate electrode, the source electrode, and the drain electrode; a lipid bilayer around the nanotube or nanowire, and a sensing element connected to the lipid bilayer.

Design Strategies for Aptamer-Based Biosensors

PubMed Central

Han, Kun; Liang, Zhiqiang; Zhou, Nandi

2010-01-01

Aptamers have been widely used as recognition elements for biosensor construction, especially in the detection of proteins or small molecule targets, and regarded as promising alternatives for antibodies in bioassay areas. In this review, we present an overview of reported design strategies for the fabrication of biosensors and classify them into four basic modes: target-induced structure switching mode, sandwich or sandwich-like mode, target-induced dissociation/displacement mode and competitive replacement mode. In view of the unprecedented advantages brought about by aptamers and smart design strategies, aptamer-based biosensors are expected to be one of the most promising devices in bioassay related applications. PMID:22399891

Quantum confinement effects in lithographic sub-5 nm Silicon nanowire fets and integration of si nanograting fet biosensors

NASA Astrophysics Data System (ADS)

Trivedi, Krutarth B.

In recent years, widespread accessibility to reliable nanofabrication techniques such as high resolution electron beam lithography as well as development of innovative techniques such as nanoimprint lithography and chemically grown nano-materials like carbon nanotubes and graphene have spurred a boom in many fields of research involving nanoscale features and devices. The breadth of fields in which nanoscale features represent a new paradigm is staggering. Scaling down device dimensions to nanoscale enables non-classical quantum behavior and allows for interaction with similarly sized natural materials, like proteins and DNA, as never before, affording an unprecedented level of performance and control and fostering a seemingly boundless array of unique applications. Much of the research effort has been directed toward understanding such interactions to leverage the potential of nanoscale devices to enhance electronic and medical technology. In keeping with the spirit of application based research, my graduate research career has spanned the development of nanoimprint techniques and devices for novel applications, demonstration and study of sub-5 nm Si nanowire FETs exhibiting tangible performance enhancement over conventional MOSFETs, and development of an integrated Si nanograting FET based biosensor and related framework. The following dissertation details my work in fabrication of sub-5 nm Si nanowire FETs and characterization of quantum confinement effects in charge transport of FETs with 2D and 1D channel geometry, fabrication and characterization of schottky contact Si nanograting FET sensors, integration of miniaturized Si nanograting FET biosensors into Chip-in-Strip(c) packaging, development of an automated microfluidic sensing system, and investigation of electrochemical considerations in the Si nanograting FET biosensor gate stack followed by development of a novel patent-pending strategy for a lithographically patterned on-chip gate electrode.

Bienzyme system for the biocatalyzed deposition of polyaniline templated by multiwalled carbon nanotubes: a biosensor design.

PubMed

Sheng, Qinglin; Zheng, Jianbin

2009-02-15

A novel method based on covalent attachment of two enzymes, glucose oxidase (GOD) and horseradish peroxide (HRP), onto carboxylic-derived multiwalled carbon nanotubes (MWNTs) for the deposition of electroactive polyaniline (PANI) under ambient conditions is described. Ultraviolet-visible spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and transmission electron microscopy were used to characterize the assembling of bienzyme and the morphology of PANI|MWNTs. Under the bienzyme biocatalytic condition, a head-to-tail structure of PANI templated by MWNTs was formed. The voltammetric characteristics of the resulting biosensor were investigated by cyclic voltammetry in the presence of glucose. The current response of PANI was linearly related to glucose concentration between 0.05 and 12.0mM with a correlation coefficient of 0.994. The synergistic performance of bienzyme, highly efficient polymerization, and templated deposition provide a general platform for the synthesis of nanowires and nanocircuits, the construction of bioelectronic devices, and the design of novel biosensors.

Direct electrodeposition of porous gold nanowire arrays for biosensing applications.

PubMed

Zhang, Xinyi; Li, Dan; Bourgeois, Laure; Wang, Huanting; Webley, Paul A

2009-02-02

Nanochannel alumina templates are used as templates for fabrication of porous gold nanowire arrays by a direct electrodeposition method. After modification with glucose oxidase, a porous gold nanowire-array electrode is shown to be an excellent electrochemical biosensor for the detection of glucose. The picture shows an SEM image of a nanowire array after removal of the alumina template by acid dissolution. We report the fabrication of porous gold nanowire arrays by means of a one-step electrodeposition method utilizing nanochannel alumina templates. The microstructure of gold nanowires depends strongly on the current density. The formation of porous gold nanowires is attributed to disperse crystallization under conditions of low nucleation rate. Interfacial electron transport through the porous gold nanowires is studied by electrochemical impedance spectroscopy. Cyclic voltammetric studies on the porous gold nanowire arrays reveal a low-potential electrocatalytic response towards hydrogen peroxide. The properties of the glucose oxidase modified porous gold nanowire array electrode are elucidated and compared with those of nonporous enzyme electrodes. The glucose oxidase modified porous gold nanowire-array electrode is shown to be an excellent electrochemical biosensor for the detection of glucose.

Fundamental Design Principles for Transcription-Factor-Based Metabolite Biosensors.

PubMed

Mannan, Ahmad A; Liu, Di; Zhang, Fuzhong; Oyarzún, Diego A

2017-10-20

Metabolite biosensors are central to current efforts toward precision engineering of metabolism. Although most research has focused on building new biosensors, their tunability remains poorly understood and is fundamental for their broad applicability. Here we asked how genetic modifications shape the dose-response curve of biosensors based on metabolite-responsive transcription factors. Using the lac system in Escherichia coli as a model system, we built promoter libraries with variable operator sites that reveal interdependencies between biosensor dynamic range and response threshold. We developed a phenomenological theory to quantify such design constraints in biosensors with various architectures and tunable parameters. Our theory reveals a maximal achievable dynamic range and exposes tunable parameters for orthogonal control of dynamic range and response threshold. Our work sheds light on fundamental limits of synthetic biology designs and provides quantitative guidelines for biosensor design in applications such as dynamic pathway control, strain optimization, and real-time monitoring of metabolism.

Applications of one-dimensional structured nanomaterials as biosensors and transparent electronics

NASA Astrophysics Data System (ADS)

Ishikawa, Fumiaki

This dissertation presents applications of one-dimensional structured nanomaterials, carbon nanotubes and In2O3 nanowires, for biosensors and transparent electronics. Chapter 1 gives the motivation to study applications of one-dimensional structured nanomaterials, and also brief introduction to structure, synthesis, and electronic properties of carbon nanotubes and In2O3 nanowires. In Chapter 2, introduction and motivation of biosensors using nanotubes/nanowires is given, followed by an overview on important background knowledge and concepts in biosensing. In Chapter 3, application of carbon nanotube biosensors toward brown tide algae detection is presented. Our devices successfully detected a brown tide marker selectively with real-time response. In Chapter 4, we demonstrate that In2O3 nanowire biosensors coupled with an antibody mimic protein (Fibronectin, Fn) can be used to detect nucleocapsid (N) protein, a biomarker for severe acute respiratory syndrome (SARS), at concentrations to below the sub-nanomolar range. In Chapter 5, we develop an analytical method to calibrate nanowire biosensor responses that can suppress the device-to-device variation in sensing response significantly. In Chapter 6, we investigate the effect of nanotube density on the biosensor performance, and proved that it plays an important role through systematic studies. In Chapter 7, I propose a future direction of nanobiosensors research, and show preliminary results along the proposed direction. I first present a concept of an ideal bioassay system with a list of requirements for the system, and propose the strategy of multi-integration to establish a system based on nanobiosensors that satisfies all of the requirements. In Chapter 8, we demonstrate high performance fully transparent transistors based on transfer printed aligned carbon nanotubes on both rigid and flexible substrates. We achieved device mobility as high as 1,300 cm 2V-1s-1 on glass substrates, which is the highest among

An auto-biotinylated bifunctional protein nanowire for ultra-sensitive molecular biosensing.

PubMed

Men, Dong; Zhang, Zhi-Ping; Guo, Yong-Chao; Zhu, Duan-Hao; Bi, Li-Jun; Deng, Jiao-Yu; Cui, Zong-Qiang; Wei, Hong-Ping; Zhang, Xian-En

2010-12-15

In order to obtain an ultra-sensitive molecular biosensor, we designed an auto-biotinylated bifunctional protein nanowire (bFPNw) based on the self-assembly of a yeast amyloid protein, Sup35, to which protein G and a biotin acceptor peptide (BAP) were genetically fused. These auto-biotinylated bFPNws can transfer hundreds of commercially available diagnostic enzymes to an antigen-antibody complex via the biotin-avidin system, greatly enhancing the sensitivity of immune-biosensing. Compared to our previously reported seeding-induced bFPNws (Men et al., 2009), these auto-biotinylated bFPNws gave greater signal amplification, reduced non-specific binding and improved stability. The auto-biotinylated self-assembled bFPNw molecular biosensors were applied to detect Yersinia pestis (Y. pestis) F1 antigen and showed a 2000- to 4000-fold increase in sensitivity compared to traditional immunoassays, demonstrating the potential use of these self-assembling protein nanowires in biosensing. Copyright © 2010 Elsevier B.V. All rights reserved.

Optical design of nanowire absorbers for wavelength selective photodetectors

PubMed Central

Mokkapati, S.; Saxena, D.; Tan, H. H.; Jagadish, C.

2015-01-01

We propose the optical design for the absorptive element of photodetectors to achieve wavelength selective photo response based on resonant guided modes supported in semiconductor nanowires. We show that the waveguiding properties of nanowires result in very high absorption efficiency that can be exploited to reduce the volume of active semiconductor compared to planar photodetectors, without compromising the photocurrent. We present a design based on a group of nanowires with varying diameter for multi-color photodetectors with small footprint. We discuss the effect of a dielectric shell around the nanowires on the absorption efficiency and present a simple approach to optimize the nanowire diameter-dielectric shell thickness for maximizing the absorption efficiency. PMID:26469227

Customization of Protein Single Nanowires for Optical Biosensing.

PubMed

Sun, Yun-Lu; Sun, Si-Ming; Wang, Pan; Dong, Wen-Fei; Zhang, Lei; Xu, Bin-Bin; Chen, Qi-Dai; Tong, Li-Min; Sun, Hong-Bo

2015-06-24

An all-protein single-nanowire optical biosensor is constructed by a facile and general femtosecond laser direct writing approach with nanoscale structural customization. As-formed protein single nanowires show excellent optical properties (fine waveguiding performance and bio-applicable transmission windows), and are utilized as evanescent optical nanobiosensors for label-free biotin detection. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Protein-mimicking nanowire-inspired electro-catalytic biosensor for probing acetylcholinesterase activity and its inhibitors.

PubMed

Zhang, Qingqing; Hu, Yufang; Wu, Di; Ma, Shaohua; Wang, Jiao; Rao, Jiajia; Xu, Lihua; Xu, Huan; Shao, Huili; Guo, Zhiyong; Wang, Sui

2018-06-01

A highly sensitive electrochemical biosensor based on the synthetized L-Cysteine-Ag(I) coordination polymer (L-Cys-Ag(I) CP), which looks like a protein-mimicking nanowire, was constructed to detect acetylcholinesterase (AChE) activity and screen its inhibitors. This sensing strategy involves the reaction of acetylcholine chloride (ACh) with acetylcholinesterase (AChE) to form choline that is in turn catalytically oxidized by choline oxidase (ChOx) to produce hydrogen peroxide (H 2 O 2 ), thus L-Cys-Ag(I) CP possesses the electro-catalytic property to H 2 O 2 reduction. Herein, the protein-mimicking nanowire-based platform was capable of investigating successive of H 2 O 2 effectively by amperometric i-t (current-time) response, and was further applied for the turn-on electrochemical detection of AChE activity. The proposed sensor is highly sensitive (limit of detection is 0.0006 U/L) and is feasible for screening inhibitors of AChE. The model for AChE inhibition was further established and two traditional AChE inhibitors (donepezil and tacrine) were employed to verify the feasibility of the system. The IC 5 0 of donepezil and tacrine were estimated to be 1.4 nM and 3.5 nM, respectively. The developed protocol provides a new and promising platform for probing AChE activity and screening its inhibitors with low cost, high sensitivity and selectivity. Copyright © 2018 Elsevier B.V. All rights reserved.

Vertically aligned nanowires from boron-doped diamond.

PubMed

Yang, Nianjun; Uetsuka, Hiroshi; Osawa, Eiji; Nebel, Christoph E

2008-11-01

Vertically aligned diamond nanowires with controlled geometrical properties like length and distance between wires were fabricated by use of nanodiamond particles as a hard mask and by use of reactive ion etching. The surface structure, electronic properties, and electrochemical functionalization of diamond nanowires were characterized by atomic force microscopy (AFM) and scanning tunneling microscopy (STM) as well as electrochemical techniques. AFM and STM experiments show that diamond nanowire etched for 10 s have wire-typed structures with 3-10 nm in length and with typically 11 nm spacing in between. The electrode active area of diamond nanowires is enhanced by a factor of 2. The functionalization of nanowire tips with nitrophenyl molecules is characterized by STM on clean and on nitrophenyl molecule-modified diamond nanowires. Tip-modified diamond nanowires are promising with respect to biosensor applications where controlled biomolecule bonding is required to improve chemical stability and sensing significantly.

Flexible Molybdenum Electrodes towards Designing Affinity Based Protein Biosensors

PubMed Central

Kamakoti, Vikramshankar; Panneer Selvam, Anjan; Radha Shanmugam, Nandhinee; Muthukumar, Sriram; Prasad, Shalini

2016-01-01

Molybdenum electrode based flexible biosensor on porous polyamide substrates has been fabricated and tested for its functionality as a protein affinity based biosensor. The biosensor performance was evaluated using a key cardiac biomarker; cardiac Troponin-I (cTnI). Molybdenum is a transition metal and demonstrates electrochemical behavior upon interaction with an electrolyte. We have leveraged this property of molybdenum for designing an affinity based biosensor using electrochemical impedance spectroscopy. We have evaluated the feasibility of detection of cTnI in phosphate-buffered saline (PBS) and human serum (HS) by measuring impedance changes over a frequency window from 100 mHz to 1 MHz. Increasing changes to the measured impedance was correlated to the increased dose of cTnI molecules binding to the cTnI antibody functionalized molybdenum surface. We achieved cTnI detection limit of 10 pg/mL in PBS and 1 ng/mL in HS medium. The use of flexible substrates for designing the biosensor demonstrates promise for integration with a large-scale batch manufacturing process. PMID:27438863

Flexible Molybdenum Electrodes towards Designing Affinity Based Protein Biosensors.

PubMed

Kamakoti, Vikramshankar; Panneer Selvam, Anjan; Radha Shanmugam, Nandhinee; Muthukumar, Sriram; Prasad, Shalini

2016-07-18

Molybdenum electrode based flexible biosensor on porous polyamide substrates has been fabricated and tested for its functionality as a protein affinity based biosensor. The biosensor performance was evaluated using a key cardiac biomarker; cardiac Troponin-I (cTnI). Molybdenum is a transition metal and demonstrates electrochemical behavior upon interaction with an electrolyte. We have leveraged this property of molybdenum for designing an affinity based biosensor using electrochemical impedance spectroscopy. We have evaluated the feasibility of detection of cTnI in phosphate-buffered saline (PBS) and human serum (HS) by measuring impedance changes over a frequency window from 100 mHz to 1 MHz. Increasing changes to the measured impedance was correlated to the increased dose of cTnI molecules binding to the cTnI antibody functionalized molybdenum surface. We achieved cTnI detection limit of 10 pg/mL in PBS and 1 ng/mL in HS medium. The use of flexible substrates for designing the biosensor demonstrates promise for integration with a large-scale batch manufacturing process.

A Highly Responsive Silicon Nanowire/Amplifier MOSFET Hybrid Biosensor

DTIC Science & Technology

2015-07-21

biosensor. The insets show a magnified view of the SiNW channel region (W = 55 nm). ( c ) Photograph of the biosensor chip fabricated via a top-down method...of the SiNW FET is 147 mV/decade. (b) VT and ( c ) ISINW at different pH levels; these values were extracted from Fig. 2a. VT was extracted using the...function of pH level in the hybrid biosensor. The extracted current change is 5.5 × 105 (=5.74 decade per pH). ( c ) Transient response of IMOSFET while

Design of nanostructured-based glucose biosensors

NASA Astrophysics Data System (ADS)

Komirisetty, Archana; Williams, Frances; Pradhan, Aswini; Konda, Rajini B.; Dondapati, Hareesh; Samantaray, Diptirani

2012-04-01

This paper presents the design of glucose sensors that will be integrated with advanced nano-materials, bio-coatings and electronics to create novel devices that are highly sensitive, inexpensive, accurate, and reliable. In the work presented, a glucose biosensor and its fabrication process flow have been designed. The device is based on electrochemical sensing using a working electrode with bio-functionalized zinc oxide (ZnO) nano-rods. Among all metal oxide nanostructures, ZnO nano-materials play a significant role as a sensing element in biosensors due to their properties such as high isoelectric point (IEP), fast electron transfer, non-toxicity, biocompatibility, and chemical stability which are very crucial parameters to achieve high sensitivity. Amperometric enzyme electrodes based on glucose oxidase (GOx) are used due to their stability and high selectivity to glucose. The device also consists of silicon dioxide and titanium layers as well as platinum working and counter electrodes and a silver/silver chloride reference electrode. Currently, the biosensors are being fabricated using the process flow developed. Once completed, the sensors will be bio-functionalized and tested to characterize their performance, including their sensitivity and stability.

Progress of new label-free techniques for biosensors: a review.

PubMed

Sang, Shengbo; Wang, Yajun; Feng, Qiliang; Wei, Ye; Ji, Jianlong; Zhang, Wendong

2016-01-01

The detection techniques used in biosensors can be broadly classified into label-based and label-free. Label-based detection relies on the specific properties of labels for detecting a particular target. In contrast, label-free detection is suitable for the target molecules that are not labeled or the screening of analytes which are not easy to tag. Also, more types of label-free biosensors have emerged with developments in biotechnology. The latest developed techniques in label-free biosensors, such as field-effect transistors-based biosensors including carbon nanotube field-effect transistor biosensors, graphene field-effect transistor biosensors and silicon nanowire field-effect transistor biosensors, magnetoelastic biosensors, optical-based biosensors, surface stress-based biosensors and other type of biosensors based on the nanotechnology are discussed. The sensing principles, configurations, sensing performance, applications, advantages and restriction of different label-free based biosensors are considered and discussed in this review. Most concepts included in this survey could certainly be applied to the development of this kind of biosensor in the future.

A CMOS-Compatible Poly-Si Nanowire Device with Hybrid Sensor/Memory Characteristics for System-on-Chip Applications

PubMed Central

Chen, Min-Cheng; Chen, Hao-Yu; Lin, Chia-Yi; Chien, Chao-Hsin; Hsieh, Tsung-Fan; Horng, Jim-Tong; Qiu, Jian-Tai; Huang, Chien-Chao; Ho, Chia-Hua; Yang, Fu-Liang

2012-01-01

This paper reports a versatile nano-sensor technology using “top-down” poly-silicon nanowire field-effect transistors (FETs) in the conventional Complementary Metal-Oxide Semiconductor (CMOS)-compatible semiconductor process. The nanowire manufacturing technique reduced nanowire width scaling to 50 nm without use of extra lithography equipment, and exhibited superior device uniformity. These n type polysilicon nanowire FETs have positive pH sensitivity (100 mV/pH) and sensitive deoxyribonucleic acid (DNA) detection ability (100 pM) at normal system operation voltages. Specially designed oxide-nitride-oxide buried oxide nanowire realizes an electrically Vth-adjustable sensor to compensate device variation. These nanowire FETs also enable non-volatile memory application for a large and steady Vth adjustment window (>2 V Programming/Erasing window). The CMOS-compatible manufacturing technique of polysilicon nanowire FETs offers a possible solution for commercial System-on-Chip biosensor application, which enables portable physiology monitoring and in situ recording. PMID:22666012

Computational design of auxotrophy-dependent microbial biosensors for combinatorial metabolic engineering experiments.

PubMed

Tepper, Naama; Shlomi, Tomer

2011-01-21

Combinatorial approaches in metabolic engineering work by generating genetic diversity in a microbial population followed by screening for strains with improved phenotypes. One of the most common goals in this field is the generation of a high rate chemical producing strain. A major hurdle with this approach is that many chemicals do not have easy to recognize attributes, making their screening expensive and time consuming. To address this problem, it was previously suggested to use microbial biosensors to facilitate the detection and quantification of chemicals of interest. Here, we present novel computational methods to: (i) rationally design microbial biosensors for chemicals of interest based on substrate auxotrophy that would enable their high-throughput screening; (ii) predict engineering strategies for coupling the synthesis of a chemical of interest with the production of a proxy metabolite for which high-throughput screening is possible via a designed bio-sensor. The biosensor design method is validated based on known genetic modifications in an array of E. coli strains auxotrophic to various amino-acids. Predicted chemical production rates achievable via the biosensor-based approach are shown to potentially improve upon those predicted by current rational strain design approaches. (A Matlab implementation of the biosensor design method is available via http://www.cs.technion.ac.il/~tomersh/tools).

Development of an electrochemical biosensor for vitamin B12 using D-phenylalanine nanotubes

NASA Astrophysics Data System (ADS)

Moazeni, Maryam; Karimzadeh, Fathallah; Kermanpur, Ahmad; Allafchian, Alireza

2018-01-01

In the past decades, biosensors are one of the most interesting topics among researchers and scientist. The biosensors are used in several applications such as determining food quality, control and diagnose clinical problems and metabolic control. Therefore, many efforts have been carried out to design and develop a new generation of these systems. On the other hand nanotechnology by improving the performance of sensors has created an excellent outlook. Using nanomaterials such as nanoparticles, nanotubes, nanowires, and nanorods in diagnostic tools has been significantly increased accuracy, sensitivity and improved detection limits in sensors. In this study, the one-dimensional morphology of the D-phenylalanine was assembled on the surface of the gold electrode. In the next step electrochemical performance of the modified electrode was investigated by Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and Differential Pals Voltammograms (DPV). Finally, by measuring the different concentrations of vitamin B12, the detection limit of the biosensor was obtained 1.6 µM.

CONDUCTING-POLYMER NANOWIRE IMMUNOSENSOR ARRAYS FOR MICROBIAL PATHOGENS

EPA Science Inventory

The lack of methods for routine rapid and sensitive detection and quantification of specific pathogens has limited the amount of information available on their occurrence in drinking water and other environmental samples. The nanowire biosensor arrays developed in this study w...

Design Architecture of field-effect transistor with back gate electrode for biosensor application

NASA Astrophysics Data System (ADS)

Fathil, M. F. M.; Arshad, M. K. Md.; Hashim, U.; Ruslinda, A. R.; Gopinath, Subash C. B.; M. Nuzaihan M., N.; Ayub, R. M.; Adzhri, R.; Zaki, M.; Azman, A. H.

2016-07-01

This paper presents the preparation method of photolithography chrome mask design used in fabrication process of field-effect transistor with back gate biasing based biosensor. Initially, the chrome masks are designed by studying the process flow of the biosensor fabrication, followed by drawing of the actual chrome mask using the AutoCAD software. The overall width and length of the device is optimized at 16 mm and 16 mm, respectively. Fabrication processes of the biosensor required five chrome masks, which included source and drain formation mask, the back gate area formation mask, electrode formation mask, front gate area formation mask, and passivation area formation mask. The complete chrome masks design will be sent for chrome mask fabrication and for future use in biosensor fabrication.

Design architecture of double spiral interdigitated electrode with back gate electrode for biosensor application

NASA Astrophysics Data System (ADS)

Fathil, M. F. M.; Arshad, M. K. Md.; Hashim, U.; Ruslinda, A. R.; Gopinath, Subash C. B.; M. Nuzaihan M., N.; Ayub, R. M.; Adzhri, R.; Zaki, M.; Azman, A. H.

2016-07-01

This paper presents the preparation method of photolithography chrome mask design used in fabrication process of double spiral interdigitated electrode with back gate biasing based biosensor. By learning the fabrication process flow of the biosensor, the chrome masks are designed through drawing using the AutoCAD software. The overall width and length of the device is optimized at 7.0 mm and 10.0 mm, respectively. Fabrication processes of the biosensor required three chrome masks, which included back gate opening, spiral IDE formation, and passivation area formation. The complete chrome masks design will be sent for chrome mask fabrication and for future use in biosensor fabrication.

Biosensor properties of SOI nanowire transistors with a PEALD Al{sub 2}O{sub 3} dielectric protective layer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Popov, V. P., E-mail: popov@isp.nsc.ru; Ilnitskii, M. A.; Zhanaev, E. D.

2016-05-15

The properties of protective dielectric layers of aluminum oxide Al{sub 2}O{sub 3} applied to prefabricated silicon-nanowire transistor biochips by the plasma enhanced atomic layer deposition (PEALD) method before being housed are studied depending on the deposition and annealing modes. Coating the natural silicon oxide with a nanometer Al{sub 2}O{sub 3} layer insignificantly decreases the femtomole sensitivity of biosensors, but provides their stability in bioliquids. In deionized water, transistors with annealed aluminum oxide are closed due to the trapping of negative charges of <(1–10) × 10{sup 11} cm{sup −2} at surface states. The application of a positive potential to the substratemore » (V{sub sub} > 25 V) makes it possible to eliminate the negative charge and to perform multiple measurements in liquid at least for half a year.« less

CMOS-Compatible Silicon Nanowire Field-Effect Transistor Biosensor: Technology Development toward Commercialization

PubMed Central

Wolfrum, Bernhard; Thierry, Benjamin

2018-01-01

Owing to their two-dimensional confinements, silicon nanowires display remarkable optical, magnetic, and electronic properties. Of special interest has been the development of advanced biosensing approaches based on the field effect associated with silicon nanowires (SiNWs). Recent advancements in top-down fabrication technologies have paved the way to large scale production of high density and quality arrays of SiNW field effect transistor (FETs), a critical step towards their integration in real-life biosensing applications. A key requirement toward the fulfilment of SiNW FETs’ promises in the bioanalytical field is their efficient integration within functional devices. Aiming to provide a comprehensive roadmap for the development of SiNW FET based sensing platforms, we critically review and discuss the key design and fabrication aspects relevant to their development and integration within complementary metal-oxide-semiconductor (CMOS) technology. PMID:29751688

CMOS-Compatible Silicon Nanowire Field-Effect Transistor Biosensor: Technology Development toward Commercialization.

PubMed

Tran, Duy Phu; Pham, Thuy Thi Thanh; Wolfrum, Bernhard; Offenhäusser, Andreas; Thierry, Benjamin

2018-05-11

Owing to their two-dimensional confinements, silicon nanowires display remarkable optical, magnetic, and electronic properties. Of special interest has been the development of advanced biosensing approaches based on the field effect associated with silicon nanowires (SiNWs). Recent advancements in top-down fabrication technologies have paved the way to large scale production of high density and quality arrays of SiNW field effect transistor (FETs), a critical step towards their integration in real-life biosensing applications. A key requirement toward the fulfilment of SiNW FETs' promises in the bioanalytical field is their efficient integration within functional devices. Aiming to provide a comprehensive roadmap for the development of SiNW FET based sensing platforms, we critically review and discuss the key design and fabrication aspects relevant to their development and integration within complementary metal-oxide-semiconductor (CMOS) technology.

Electrical conductivity measurements of bacterial nanowires from Pseudomonas aeruginosa

NASA Astrophysics Data System (ADS)

Maruthupandy, Muthusamy; Anand, Muthusamy; Maduraiveeran, Govindhan; Sait Hameedha Beevi, Akbar; Jeeva Priya, Radhakrishnan

2015-12-01

The extracellular appendages of bacteria (flagella) that transfer electrons to electrodes are called bacterial nanowires. This study focuses on the isolation and separation of nanowires that are attached via Pseudomonas aeruginosa bacterial culture. The size and roughness of separated nanowires were measured using transmission electron microscopy (TEM) and atomic force microscopy (AFM), respectively. The obtained bacterial nanowires indicated a clear image of bacterial nanowires measuring 16 nm in diameter. The formation of bacterial nanowires was confirmed by microscopic studies (AFM and TEM) and the conductivity nature of bacterial nanowire was investigated by electrochemical techniques. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), which are nondestructive voltammetry techniques, suggest that bacterial nanowires could be the source of electrons—which may be used in various applications, for example, microbial fuel cells, biosensors, organic solar cells, and bioelectronic devices. Routine analysis of electron transfer between bacterial nanowires and the electrode was performed, providing insight into the extracellular electron transfer (EET) to the electrode. CV revealed the catalytic electron transferability of bacterial nanowires and electrodes and showed excellent redox activities. CV and EIS studies showed that bacterial nanowires can charge the surface by producing and storing sufficient electrons, behave as a capacitor, and have features consistent with EET. Finally, electrochemical studies confirmed the development of bacterial nanowires with EET. This study suggests that bacterial nanowires can be used to fabricate biomolecular sensors and nanoelectronic devices.

Nanowire systems: technology and design

PubMed Central

Gaillardon, Pierre-Emmanuel; Amarù, Luca Gaetano; Bobba, Shashikanth; De Marchi, Michele; Sacchetto, Davide; De Micheli, Giovanni

2014-01-01

Nanosystems are large-scale integrated systems exploiting nanoelectronic devices. In this study, we consider double independent gate, vertically stacked nanowire field effect transistors (FETs) with gate-all-around structures and typical diameter of 20 nm. These devices, which we have successfully fabricated and evaluated, control the ambipolar behaviour of the nanostructure by selectively enabling one type of carriers. These transistors work as switches with electrically programmable polarity and thus realize an exclusive or operation. The intrinsic higher expressive power of these FETs, when compared with standard complementary metal oxide semiconductor technology, enables us to realize more efficient logic gates, which we organize as tiles to realize nanowire systems by regular arrays. This article surveys both the technology for double independent gate FETs as well as physical and logic design tools to realize digital systems with this fabrication technology. PMID:24567471

Nanomaterials towards fabrication of cholesterol biosensors: Key roles and design approaches.

PubMed

Saxena, Urmila; Das, Asim Bikas

2016-01-15

Importance of cholesterol biosensors is already recognized in the clinical diagnosis of cardiac and brain vascular diseases as discernible from the enormous amount of research in this field. Nevertheless, the practical application of a majority of the fabricated cholesterol biosensors is ordinarily limited by their inadequate performance in terms of one or more analytical parameters including stability, sensitivity and detection limit. Nanoscale materials offer distinctive size tunable electronic, catalytic and optical properties which opened new opportunities for designing highly efficient biosensor devices. Incorporation of nanomaterials in biosensing devices has found to improve the electroactive surface, electronic conductivity and biocompatibility of the electrode surfaces which then improves the analytical performance of the biosensors. Here we have reviewed recent advances in nanomaterial-based cholesterol biosensors. Foremost, the diverse roles of nanomaterials in these sensor systems have been discussed. Later, we have exhaustively explored the strategies used for engineering cholesterol biosensors with nanotubes, nanoparticles and nanocomposites. Finally, this review concludes with future outlook signifying some challenges of these nanoengineered cholesterol sensors. Copyright © 2015 Elsevier B.V. All rights reserved.

Label-free SnO2 nanowire FET biosensor for protein detection

NASA Astrophysics Data System (ADS)

Jakob, Markus H.; Dong, Bo; Gutsch, Sebastian; Chatelle, Claire; Krishnaraja, Abinaya; Weber, Wilfried; Zacharias, Margit

2017-06-01

Novel tin oxide field-effect-transistors (SnO2 NW-FET) for pH and protein detection applicable in the healthcare sector are reported. With a SnO2 NW-FET the proof-of-concept of a bio-sensing device is demonstrated using the carrier transport control of the FET channel by a (bio-) liquid modulated gate. Ultra-thin Al2O3 fabricated by a low temperature atomic layer deposition (ALD) process represents a sensitive layer to H+ ions safeguarding the nanowire at the same time. Successful pH sensitivity is demonstrated for pH ranging from 3 to 10. For protein detection, the SnO2 NW-FET is functionalized with a receptor molecule which specifically interacts with the protein of interest to be detected. The feasibility of this approach is demonstrated via the detection of a biotinylated protein using a NW-FET functionalized with streptavidin. An immediate label-free electronic read-out of the signal is shown. The well-established Enzyme-Linked Immunosorbent Assay (ELISA) method is used to determine the optimal experimental procedure which would enable molecular binding events to occur while being compatible with a final label-free electronic read-out on a NW-FET. Integration of the bottom-up fabricated SnO2 NW-FET pH- and biosensor into a microfluidic system (lab-on-a-chip) allows the automated analysis of small volumes in the 400 μl range as would be desired in portable on-site point-of-care (POC) devices for medical diagnosis.

Design, Optimization and Application of Small Molecule Biosensor in Metabolic Engineering.

PubMed

Liu, Yang; Liu, Ye; Wang, Meng

2017-01-01

The development of synthetic biology and metabolic engineering has painted a great future for the bio-based economy, including fuels, chemicals, and drugs produced from renewable feedstocks. With the rapid advance of genome-scale modeling, pathway assembling and genome engineering/editing, our ability to design and generate microbial cell factories with various phenotype becomes almost limitless. However, our lack of ability to measure and exert precise control over metabolite concentration related phenotypes becomes a bottleneck in metabolic engineering. Genetically encoded small molecule biosensors, which provide the means to couple metabolite concentration to measurable or actionable outputs, are highly promising solutions to the bottleneck. Here we review recent advances in the design, optimization and application of small molecule biosensor in metabolic engineering, with particular focus on optimization strategies for transcription factor (TF) based biosensors.

Design, Optimization and Application of Small Molecule Biosensor in Metabolic Engineering

PubMed Central

Liu, Yang; Liu, Ye; Wang, Meng

2017-01-01

The development of synthetic biology and metabolic engineering has painted a great future for the bio-based economy, including fuels, chemicals, and drugs produced from renewable feedstocks. With the rapid advance of genome-scale modeling, pathway assembling and genome engineering/editing, our ability to design and generate microbial cell factories with various phenotype becomes almost limitless. However, our lack of ability to measure and exert precise control over metabolite concentration related phenotypes becomes a bottleneck in metabolic engineering. Genetically encoded small molecule biosensors, which provide the means to couple metabolite concentration to measurable or actionable outputs, are highly promising solutions to the bottleneck. Here we review recent advances in the design, optimization and application of small molecule biosensor in metabolic engineering, with particular focus on optimization strategies for transcription factor (TF) based biosensors. PMID:29089935

Fabrication and Performance Study on Individual Zno Nanowires Based Bioelectrode

NASA Astrophysics Data System (ADS)

Zhao, Yanguang; Yan, Xiaoqin; Kang, Zhuo; Lin, Pei

2012-08-01

One-dimensional zinc oxide nanowires (ZnO NWs) have unique advantages for use in biosensors as follows: oxide stable surface, excellent biosafety, high specific surface area, high isoelectric point (IEP = 9.5). In this work, we have prepared a kind of electrochemical bioelectrode based on individual ZnO NWs. Here, ZnO NWs with high quality were successfully synthesized by CVD method, which were characterized by scanning electron microscopy, X-ray diffraction and photoluminescence. Then the Raman spectra and electrical characterization demonstrated the adsorption of uricase on ZnO wires. At last, a series of electrochemical measurements were carried out by using an electrochemical workstation with a conventional three-electrode system to obtain the cyclic voltammetry characteristics of the bioelectrodes. The excellent performance of the fabricated bioelectrode implies the potential application for single ZnO nanowire to construct electrochemical biosensor for the detection of uric acid.

Top-Down Nanofabrication and Characterization of 20 nm Silicon Nanowires for Biosensing Applications

PubMed Central

M. N, M. Nuzaihan; Hashim, U.; Md Arshad, M. K.; Ruslinda, A. Rahim; Rahman, S. F. A.; Fathil, M. F. M.; Ismail, Mohd. H.

2016-01-01

A top-down nanofabrication approach is used to develop silicon nanowires from silicon-on-insulator (SOI) wafers and involves direct-write electron beam lithography (EBL), inductively coupled plasma-reactive ion etching (ICP-RIE) and a size reduction process. To achieve nanometer scale size, the crucial factors contributing to the EBL and size reduction processes are highlighted. The resulting silicon nanowires, which are 20 nm in width and 30 nm in height (with a triangular shape) and have a straight structure over the length of 400 μm, are fabricated precisely at the designed location on the device. The device is applied in biomolecule detection based on the changes in drain current (Ids), electrical resistance and conductance of the silicon nanowires upon hybridization to complementary target deoxyribonucleic acid (DNA). In this context, the scaled-down device exhibited superior performances in terms of good specificity and high sensitivity, with a limit of detection (LOD) of 10 fM, enables for efficient label-free, direct and higher-accuracy DNA molecules detection. Thus, this silicon nanowire can be used as an improved transducer and serves as novel biosensor for future biomedical diagnostic applications. PMID:27022732

Yeast-based biosensors: design and applications.

PubMed

Adeniran, Adebola; Sherer, Michael; Tyo, Keith E J

2015-02-01

Yeast-based biosensing (YBB) is an exciting research area, as many studies have demonstrated the use of yeasts to accurately detect specific molecules. Biosensors incorporating various yeasts have been reported to detect an incredibly large range of molecules including but not limited to odorants, metals, intracellular metabolites, carcinogens, lactate, alcohols, and sugars. We review the detection strategies available for different types of analytes, as well as the wide range of output methods that have been incorporated with yeast biosensors. We group biosensors into two categories: those that are dependent upon transcription of a gene to report the detection of a desired molecule and those that are independent of this reporting mechanism. Transcription-dependent biosensors frequently depend on heterologous expression of sensing elements from non-yeast organisms, a strategy that has greatly expanded the range of molecules available for detection by YBBs. Transcription-independent biosensors circumvent the problem of sensing difficult-to-detect analytes by instead relying on yeast metabolism to generate easily detected molecules when the analyte is present. The use of yeast as the sensing element in biosensors has proven to be successful and continues to hold great promise for a variety of applications. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.

Electrochemical Biosensors: A Solution to Pollution Detection with Reference to Environmental Contaminants.

PubMed

Hernandez-Vargas, Gustavo; Sosa-Hernández, Juan Eduardo; Saldarriaga-Hernandez, Sara; Villalba-Rodríguez, Angel M; Parra-Saldivar, Roberto; Iqbal, Hafiz M N

2018-03-24

The increasing environmental pollution with particular reference to emerging contaminants, toxic heavy elements, and other hazardous agents is a serious concern worldwide. Considering this global issue, there is an urgent need to design and develop strategic measuring techniques with higher efficacy and precision to detect a broader spectrum of numerous contaminants. The development of precise instruments can further help in real-time and in-process monitoring of the generation and release of environmental pollutants from different industrial sectors. Moreover, real-time monitoring can also reduce the excessive consumption of several harsh chemicals and reagents with an added advantage of on-site determination of contaminant composition prior to discharge into the environment. With key scientific advances, electrochemical biosensors have gained considerable attention to solve this problem. Electrochemical biosensors can be an excellent fit as an analytical tool for monitoring programs to implement legislation. Herein, we reviewed the current trends in the use of electrochemical biosensors as novel tools to detect various contaminant types including toxic heavy elements. A particular emphasis was given to screen-printed electrodes, nanowire sensors, and paper-based biosensors and their role in the pollution detection processes. Towards the end, the work is wrapped up with concluding remarks and future perspectives. In summary, electrochemical biosensors and related areas such as bioelectronics, and (bio)-nanotechnology seem to be growing areas that will have a marked influence on the development of new bio-sensing strategies in future studies.

Designed Strategies for Fluorescence-Based Biosensors for the Detection of Mycotoxins

PubMed Central

Sharma, Atul; Khan, Reem; Catanante, Gaelle; Sherazi, Tauqir A.; Bhand, Sunil; Hayat, Akhtar; Marty, Jean Louis

2018-01-01

Small molecule toxins such as mycotoxins with low molecular weight are the most widely studied biological toxins. These biological toxins are responsible for food poisoning and have the potential to be used as biological warfare agents at the toxic dose. Due to the poisonous nature of mycotoxins, effective analysis techniques for quantifying their toxicity are indispensable. In this context, biosensors have been emerged as a powerful tool to monitors toxins at extremely low level. Recently, biosensors based on fluorescence detection have attained special interest with the incorporation of nanomaterials. This review paper will focus on the development of fluorescence-based biosensors for mycotoxin detection, with particular emphasis on their design as well as properties such as sensitivity and specificity. A number of these fluorescent biosensors have shown promising results in food samples for the detection of mycotoxins, suggesting their future potential for food applications. PMID:29751687

Designed Strategies for Fluorescence-Based Biosensors for the Detection of Mycotoxins.

PubMed

Sharma, Atul; Khan, Reem; Catanante, Gaelle; Sherazi, Tauqir A; Bhand, Sunil; Hayat, Akhtar; Marty, Jean Louis

2018-05-11

Small molecule toxins such as mycotoxins with low molecular weight are the most widely studied biological toxins. These biological toxins are responsible for food poisoning and have the potential to be used as biological warfare agents at the toxic dose. Due to the poisonous nature of mycotoxins, effective analysis techniques for quantifying their toxicity are indispensable. In this context, biosensors have been emerged as a powerful tool to monitors toxins at extremely low level. Recently, biosensors based on fluorescence detection have attained special interest with the incorporation of nanomaterials. This review paper will focus on the development of fluorescence-based biosensors for mycotoxin detection, with particular emphasis on their design as well as properties such as sensitivity and specificity. A number of these fluorescent biosensors have shown promising results in food samples for the detection of mycotoxins, suggesting their future potential for food applications.

Design of highly sensitive multichannel bimetallic photonic crystal fiber biosensor

NASA Astrophysics Data System (ADS)

Hameed, Mohamed Farhat O.; Alrayk, Yassmin K. A.; Shaalan, Abdelhamid A.; El Deeb, Walid S.; Obayya, Salah S. A.

2016-10-01

A design of a highly sensitive multichannel biosensor based on photonic crystal fiber is proposed and analyzed. The suggested design has a silver layer as a plasmonic material coated by a gold layer to protect silver oxidation. The reported sensor is based on detection using the quasi transverse electric (TE) and quasi transverse magnetic (TM) modes, which offers the possibility of multichannel/multianalyte sensing. The numerical results are obtained using a finite element method with perfect matched layer boundary conditions. The sensor geometrical parameters are optimized to achieve high sensitivity for the two polarized modes. High-refractive index sensitivity of about 4750 nm/RIU (refractive index unit) and 4300 nm/RIU with corresponding resolutions of 2.1×10-5 RIU, and 2.33×10-5 RIU can be obtained according to the quasi TM and quasi TE modes of the proposed sensor, respectively. Further, the reported design can be used as a self-calibration biosensor within an unknown analyte refractive index ranging from 1.33 to 1.35 with high linearity and high accuracy. Moreover, the suggested biosensor has advantages in terms of compactness and better integration of microfluidics setup, waveguide, and metallic layers into a single structure.

Design of a macroalgae amperometric biosensor; application to the rapid monitoring of organophosphate insecticides in an agroecosystem.

PubMed

Nunes, G S; Lins, J A P; Silva, F G S; Araujo, L C; Silva, F E P S; Mendonça, C D; Badea, M; Hayat, A; Marty, J-L

2014-09-01

The immobilization of enzymes onto transducer support is a mature technology and has been successfully implemented to improve biocatalytic processes for diverse applications. However, there exists still need to design more sophisticated and specialized strategies to enhance the functional properties of the biosensors. In this work, a biosensor platform based on innovative fabrication strategy was designed, and employed for the detection of organophosphate (OP) in natural waters. The biosensor was prepared by incorporating acetylcholinesterase enzyme (AChE) to the graphite paste modified with tetracyanoquinodimethane (TCNQ) mediator, along with the use of a macroalgae (Cladaphropsis membranous) as a functional immobilization support. The novel immobilization design resulted in a synergic effect, and led to enhanced stability and sensitivity of the biosensor. The designed biosensor was used to analyze methyl parathion OP insecticide in water samples collected from a demonstrably contaminated lake of São Luis Island, Maranhão, Northeast of Brazil. Water analysis revealed that the aquatic ecosystem was polluted by sub-ppm concentrations of the OP insecticide, and a good correlation was found between values obtained through biosensor and GC-MS techniques. Our results demonstrated that macroalgae-biosensor could be used as a low-cost and sensitive screening method to detect target analyte. Copyright © 2014 Elsevier Ltd. All rights reserved.

Recovery Based Nanowire Field-Effect Transistor Detection of Pathogenic Avian Influenza DNA

NASA Astrophysics Data System (ADS)

Lin, Chih-Heng; Chu, Chia-Jung; Teng, Kang-Ning; Su, Yi-Jr; Chen, Chii-Dong; Tsai, Li-Chu; Yang, Yuh-Shyong

2012-02-01

Fast and accurate diagnosis is critical in infectious disease surveillance and management. We proposed a DNA recovery system that can easily be adapted to DNA chip or DNA biosensor for fast identification and confirmation of target DNA. This method was based on the re-hybridization of DNA target with a recovery DNA to free the DNA probe. Functionalized silicon nanowire field-effect transistor (SiNW FET) was demonstrated to monitor such specific DNA-DNA interaction using high pathogenic strain virus hemagglutinin 1 (H1) DNA of avian influenza (AI) as target. Specific electric changes were observed in real-time for AI virus DNA sensing and device recovery when nanowire surface of SiNW FET was modified with complementary captured DNA probe. The recovery based SiNW FET biosensor can be further developed for fast identification and further confirmation of a variety of influenza virus strains and other infectious diseases.

Effects of Nanowire Length and Surface Roughness on the Electrochemical Sensor Properties of Nafion-Free, Vertically Aligned Pt Nanowire Array Electrodes

PubMed Central

Li, Zhiyang; Leung, Calvin; Gao, Fan; Gu, Zhiyong

2015-01-01

In this paper, vertically aligned Pt nanowire arrays (PtNWA) with different lengths and surface roughnesses were fabricated and their electrochemical performance toward hydrogen peroxide (H2O2) detection was studied. The nanowire arrays were synthesized by electroplating Pt in nanopores of anodic aluminum oxide (AAO) template. Different parameters, such as current density and deposition time, were precisely controlled to synthesize nanowires with different surface roughnesses and various lengths from 3 μm to 12 μm. The PtNWA electrodes showed better performance than the conventional electrodes modified by Pt nanowires randomly dispersed on the electrode surface. The results indicate that both the length and surface roughness can affect the sensing performance of vertically aligned Pt nanowire array electrodes. Generally, longer nanowires with rougher surfaces showed better electrochemical sensing performance. The 12 μm rough surface PtNWA presented the largest sensitivity (654 μA·mM−1·cm−2) among all the nanowires studied, and showed a limit of detection of 2.4 μM. The 12 μm rough surface PtNWA electrode also showed good anti-interference property from chemicals that are typically present in the biological samples such as ascorbic, uric acid, citric acid, and glucose. The sensing performance in real samples (river water) was tested and good recovery was observed. These Nafion-free, vertically aligned Pt nanowires with surface roughness control show great promise as versatile electrochemical sensors and biosensors. PMID:26404303

Why self-catalyzed nanowires are most suitable for large-scale hierarchical integrated designs of nanowire nanoelectronics

NASA Astrophysics Data System (ADS)

Noor Mohammad, S.

2011-10-01

Nanowires are grown by a variety of mechanisms, including vapor-liquid-solid, vapor-quasiliquid-solid or vapor-quasisolid-solid, oxide-assisted growth, and self-catalytic growth (SCG) mechanisms. A critical analysis of the suitability of self-catalyzed nanowires, as compared to other nanowires, for next-generation technology development has been carried out. Basic causes of superiority of self-catalyzed (SCG) nanowires over other nanowires have been described. Polytypism in nanowires has been studied, and a model for polytypism has been proposed. The model predicts polytypism in good agreement with available experiments. This model, together with various evidences, demonstrates lower defects, dislocations, and stacking faults in SCG nanowires, as compared to those in other nanowires. Calculations of carrier mobility due to dislocation scattering, ionized impurity scattering, and acoustic phonon scattering explain the impact of defects, dislocations, and stacking faults on carrier transports in SCG and other nanowires. Analyses of growth mechanisms for nanowire growth directions indicate SCG nanowires to exhibit the most controlled growth directions. In-depth investigation uncovers the fundamental physics underlying the control of growth direction by the SCG mechanism. Self-organization of nanowires in large hierarchical arrays is crucial for ultra large-scale integration (ULSI). Unique features and advantages of self-organized SCG nanowires, unlike other nanowires, for this ULSI have been discussed. Investigations of nanowire dimension indicate self-catalyzed nanowires to have better control of dimension, higher stability, and higher probability, even for thinner structures. Theoretical calculations show that self-catalyzed nanowires, unlike catalyst-mediated nanowires, can have higher growth rate and lower growth temperature. Nanowire and nanotube characteristics have been found also to dictate the performance of nanoelectromechanical systems. Defects, such as

Handheld Chem/Biosensor Using Extreme Conformational Changes in Designed Binding Proteins to Enhance Surface Plasmon Resonance (SPR)

DTIC Science & Technology

2016-04-01

AFCEC-CX-TY-TR-2016-0007 HANDHELD CHEM/ BIOSENSOR USING EXTREME CONFORMATIONAL CHANGES IN DESIGNED BINDING PROTEINS TO ENHANCE SURFACE PLASMON...Include area code) 03/24/2016 Abstract 08/14/2015--03/31/2016 Handheld chem/ biosensor using extreme conformational changes in designed binding...Baltimore, Maryland on 17-21 April 2016. We propose the development of a highly sensitive handheld chem/ biosensor device using a novel class of engineered

Design of Contact Electrodes for Semiconductor Nanowire Solar Energy Harvesting Devices.

PubMed

Lin, Tzuging; Ramadurgam, Sarath; Yang, Chen

2017-04-12

Transparent, low-resistive contacts are critical for efficient solar energy harvesting devices. It is important to reconsider the material choices and electrode design as devices move from 2D films to 1D nanostructures. In this paper, we study the effectiveness of indium tin oxide (ITO) and metals, such as Ag and Cu, as contacts in 2D and 1D systems. Although ITO has been studied extensively and developed into an effective transparent contact for 2D devices, our results show that effectiveness does not translate to 1D systems. Particularly with consideration of resistance requirement, nanowires with metal shells as contacts enable better absorption within the semiconductor as compared to ITO. Furthermore, there is a strong dependence of contact performance on the semiconductor band gap and diameter of nanowires. We found that metal contacts outperform ITO for nanowire devices, regardless of the sheet resistance constraint, in the regime of diameters less than 100 nm and band-gaps greater than 1 eV. These metal shells optimized for best absorption are significantly thinner than ITO, which enables for the design of devices with high nanowire number density and consequently higher device efficiencies.

Tracing the pH dependent activation of autophagy in cancer cells by silicon nanowire-based impedance biosensor.

PubMed

Alikhani, Alireza; Gharooni, Milad; Abiri, Hamed; Farokhmanesh, Fatemeh; Abdolahad, Mohammad

2018-05-30

Monitoring the pH dependent behavior of normal and cancer cells by impedimetric biosensor based on Silicon Nanowires (SiNWs) was introduced to diagnose the invasive cancer cells. Autophagy as a biologically activated process in invasive cancer cells during acidosis, protect them from apoptosis in lower pH which presented in our work. As the autophagy is the only activated pathways which can maintain cellular proliferation in acidic media, responses of SiNW-ECIS in acidified cells could be correlated to the probability of autophagy activation in normal or cancer cells. In contrast, cell survival pathway wasn't activated in low-grade cancer cells which resulted in their acidosis. The measured electrical resistance of MCF10, MCF7, and MDA-MB468 cell lines, by SiNW sensor, in normal and acidic media were matched by the biological analyses of their vital functions. Invasive cancer cells exhibited increased electrical resistance in pH 6.5 meanwhile the two other types of the breast cells exhibited sharp (MCF10) and moderate (MCF7) decrease in their resistance. This procedure would be a new trend in microenvironment based cancer investigation. Copyright © 2018 Elsevier B.V. All rights reserved.

An innovative large scale integration of silicon nanowire-based field effect transistors

NASA Astrophysics Data System (ADS)

Legallais, M.; Nguyen, T. T. T.; Mouis, M.; Salem, B.; Robin, E.; Chenevier, P.; Ternon, C.

2018-05-01

Since the early 2000s, silicon nanowire field effect transistors are emerging as ultrasensitive biosensors while offering label-free, portable and rapid detection. Nevertheless, their large scale production remains an ongoing challenge due to time consuming, complex and costly technology. In order to bypass these issues, we report here on the first integration of silicon nanowire networks, called nanonet, into long channel field effect transistors using standard microelectronic process. A special attention is paid to the silicidation of the contacts which involved a large number of SiNWs. The electrical characteristics of these FETs constituted by randomly oriented silicon nanowires are also studied. Compatible integration on the back-end of CMOS readout and promising electrical performances open new opportunities for sensing applications.

Design and fabrication of Ni nanowires having periodically hollow nanostructures

NASA Astrophysics Data System (ADS)

Sada, Takao; Fujigaya, Tsuyohiko; Nakashima, Naotoshi

2014-09-01

We propose a concept for the design and fabrication of metal nanowires having periodically hollow nanostructures inside the pores of an anodic aluminum oxide (AAO) membrane using a sacrificial metal. In this study, nickel (Ni) and silver (Ag) were used as the base metal and the sacrificial metal, respectively. Alternating an applied potential between -0.4 and -1.0 V provided alternatively deposited Ni and Ag segments in a Ni-Ag `barcode' nanowire with a diameter of 18 or 35 nm. After etching away the Ag segments, we fabricated Ni nanowires with nanopores of 12 +/- 5.3 nm. Such nanostructure formation is explained by the formation of a Ni shell layer over the surface of the Ag segments due to the strong affinity of Ni2+ for the interior surfaces of AAO. The Ni shell layer allows the Ni segments to remain even after dissolution of the Ag segments. Because the electroplating conditions can be easily controlled, we could carefully adjust the size and pitch of the periodically hollow nanospaces. We also describe a method for the fabrication of Ni nanorods by forming an Ag shell instead of a Ni shell on the Ni-Ag barcode nanowire, in which the interior of the AAO surfaces was modified with a compound bearing a thiol group prior to electroplating.We propose a concept for the design and fabrication of metal nanowires having periodically hollow nanostructures inside the pores of an anodic aluminum oxide (AAO) membrane using a sacrificial metal. In this study, nickel (Ni) and silver (Ag) were used as the base metal and the sacrificial metal, respectively. Alternating an applied potential between -0.4 and -1.0 V provided alternatively deposited Ni and Ag segments in a Ni-Ag `barcode' nanowire with a diameter of 18 or 35 nm. After etching away the Ag segments, we fabricated Ni nanowires with nanopores of 12 +/- 5.3 nm. Such nanostructure formation is explained by the formation of a Ni shell layer over the surface of the Ag segments due to the strong affinity of Ni2+ for the

Knowledge-based design of a biosensor to quantify localized ERK activation in living cells

PubMed Central

Kummer, Lutz; Hsu, Chia-Wen; Dagliyan, Onur; MacNevin, Christopher; Kaufholz, Melanie; Zimmermann, Bastian; Dokholyan, Nikolay V.; Hahn, Klaus M.; Plückthun, Andreas

2014-01-01

Summary Investigation of protein activation in living cells is fundamental to understand how proteins are influenced by the full complement of upstream regulators they experience. We describe here the generation of a biosensor based on the Designed Ankyrin Repeat Protein (DARPin) binding scaffold suited for intracellular applications. Combining selection and evolution from libraries, knowledge-based design and efficient and rapid testing of conjugate candidates, we created an ERK activity biosensor by derivatizing a DARPin specific for phosphorylated ERK (pERK) with a solvatochromic merocyanine dye (mero87), whose fluorescence increases upon pERK binding. The biosensor specifically responded to pERK2, recognized by its conformation, but not to non-phosphorylated ERK2 or other closely related mitogen-activated kinases tested. Activated endogenous ERK was visualized in mouse embryo fibroblasts incubated in 2% serum, revealing greater activation in the nucleus, perinuclear regions, and especially the nucleoli. Activity was greatly reduced by the MEK1/2 inhibitor U0126. The DARPin-based biosensor will serve as useful tool for studying biological functions of ERK in vitro and in vivo. PMID:23790495

All-carbon suspended nanowire sensors as a rapid highly-sensitive label-free chemiresistive biosensing platform.

PubMed

Thiha, Aung; Ibrahim, Fatimah; Muniandy, Shalini; Dinshaw, Ignatius Julian; Teh, Swe Jyan; Thong, Kwai Lin; Leo, Bey Fen; Madou, Marc

2018-06-01

Nanowire sensors offer great potential as highly sensitive electrochemical and electronic biosensors because of their small size, high aspect ratios, and electronic properties. Nevertheless, the available methods to fabricate carbon nanowires in a controlled manner remain limited to expensive techniques. This paper presents a simple fabrication technique for sub-100 nm suspended carbon nanowire sensors by integrating electrospinning and photolithography techniques. Carbon Microelectromechanical Systems (C-MEMS) fabrication techniques allow fabrication of high aspect ratio carbon structures by patterning photoresist polymers into desired shapes and subsequent carbonization of resultant structures by pyrolysis. In our sensor platform, suspended nanowires were deposited by electrospinning while photolithography was used to fabricate support structures. We have achieved suspended carbon nanowires with sub-100 nm diameters in this study. The sensor platform was then integrated with a microfluidic chip to form a lab-on-chip device for label-free chemiresistive biosensing. We have investigated this nanoelectronics label-free biosensor's performance towards bacterial sensing by functionalization with Salmonella-specific aptamer probes. The device was tested with varying concentrations of Salmonella Typhimurium to evaluate sensitivity and various other bacteria to investigate specificity. The results showed that the sensor is highly specific and sensitive in detection of Salmonella with a detection limit of 10 CFU mL -1 . Moreover, this proposed chemiresistive assay has a reduced turnaround time of 5 min and sample volume requirement of 5 µL which are much less than reported in the literature. Copyright © 2018 Elsevier B.V. All rights reserved.

Nanostructures in biosensor--a review.

PubMed

Yeom, Se-Hyuk; Kang, Byoung-Ho; Kim, Kyu-Jin; Kang, Shin-Won

2011-01-01

In the 21(st) century, it is widely recognized that along with information technology (IT) and biotechnology (BT), nanotechnology (NT) will be a key field of science that will drive future developments. NT is expected to allow innovations in industrial fields such as electrical and electronics, biochemistry, environment, energy, as well as materials science by enabling the control and operation of materials at the atomic and molecular levels. In particular, the application of NT in the field of biochemistry is now enabling the realization of previously unachievable objectives.This review discusses the growth, synthesis, and biocompatible functionalization of each materials, with an emphasis on 1D nanomaterials such as CNTs, inorganic nanowires (made of Si, metals, etc.), and conducting polymer nanowires, along with 0D nanomaterials such as nanoparticles. This review also investigates the sensing principle and features of nanobiosensors made using the abovementioned materials and introduce various types of biosensors with nanostructure 0-D and 1-D. Finally, the review discusses future research objectives and research directions in the field of nanotechnology.

Multisegment nanowire sensors for the detection of DNA molecules.

PubMed

Wang, Xu; Ozkan, Cengiz S

2008-02-01

We describe a novel application for detecting specific single strand DNA sequences using multisegment nanowires via a straightforward surface functionalization method. Nanowires comprising CdTe-Au-CdTe segments are fabricated using electrochemical deposition, and electrical characterization indicates a p-type behavior for the multisegment nanostructures, in a back-to-back Schottky diode configuration. Such nanostructures modified with thiol-terminated probe DNA fragments could function as high fidelity sensors for biomolecules at very low concentration. The gold segment is utilized for functionalization and binding of single strand DNA (ssDNA) fragments while the CdTe segments at both ends serve to modulate the equilibrium Fermi level of the heterojunction device upon hybridization of the complementary DNA fragments (cDNA) to the ssDNA over the Au segment. Employing such multisegment nanowires could lead to the fabrication more sophisticated and high multispecificity biosensors via selective functionalization of individual segments for biowarfare sensing and medical diagnostics applications.

MOF-Based Membrane Encapsulated ZnO Nanowires for Enhanced Gas Sensor Selectivity.

PubMed

Drobek, Martin; Kim, Jae-Hun; Bechelany, Mikhael; Vallicari, Cyril; Julbe, Anne; Kim, Sang Sub

2016-04-06

Gas sensors are of a great interest for applications including toxic or explosive gases detection in both in-house and industrial environments, air quality monitoring, medical diagnostics, or control of food/cosmetic properties. In the area of semiconductor metal oxides (SMOs)-based sensors, a lot of effort has been devoted to improve the sensing characteristics. In this work, we report on a general methodology for improving the selectivity of SMOx nanowires sensors, based on the coverage of ZnO nanowires with a thin ZIF-8 molecular sieve membrane. The optimized ZnO@ZIF-8-based nanocomposite sensor shows markedly selective response to H2 in comparison with the pristine ZnO nanowires sensor, while showing the negligible sensing response to C7H8 and C6H6. This original MOF-membrane encapsulation strategy applied to nanowires sensor architecture pave the way for other complex 3D architectures and various types of applications requiring either gas or ion selectivity, such as biosensors, photo(catalysts), and electrodes.

Silicon nanowire biologically sensitive field effect transistors: electrical characteristics and applications.

PubMed

Rim, Taiuk; Baek, Chang-Ki; Kim, Kihyun; Jeong, Yoon-Ha; Lee, Jeong-Soo; Meyyappan, M

2014-01-01

The interest in biologically sensitive field effect transistors (BioFETs) is growing explosively due to their potential as biosensors in biomedical, environmental monitoring and security applications. Recently, adoption of silicon nanowires in BioFETs has enabled enhancement of sensitivity, device miniaturization, decreasing power consumption and emerging applications such as the 3D cell probe. In this review, we describe the device physics and operation of the silicon nanowire BioFETs along with recent advances in the field. The silicon nanowire BioFETs are basically the same as the conventional field-effect transistors (FETs) with the exceptions of nanowire channel instead of thin film and a liquid gate instead of the conventional gate. Therefore, the silicon device physics is important to understand the operation of the BioFETs. Herein, physical characteristics of the silicon nanowire FETs are described and the operational principles of the BioFETs are classified according to the number of gates and the analysis domain of the measured signal. Even the bottom-up process has merits on low-cost fabrication; the top-down process technique is highlighted here due to its reliability and reproducibility. Finally, recent advances in the silicon nanowire BioFETs in the literature are described and key features for commercialization are discussed.

How cutting-edge technologies impact the design of electrochemical (bio)sensors for environmental analysis. A review.

PubMed

Arduini, Fabiana; Cinti, Stefano; Scognamiglio, Viviana; Moscone, Danila; Palleschi, Giuseppe

2017-03-22

Through the years, scientists have developed cutting-edge technologies to make (bio)sensors more convenient for environmental analytical purposes. Technological advancements in the fields of material science, rational design, microfluidics, and sensor printing, have radically shaped biosensor technology, which is even more evident in the continuous development of sensing systems for the monitoring of hazardous chemicals. These efforts will be crucial in solving some of the problems constraining biosensors to reach real environmental applications, such as continuous analyses in field by means of multi-analyte portable devices. This review (with 203 refs.) covers the progress between 2010 and 2015 in the field of technologies enabling biosensor applications in environmental analysis, including i) printing technology, ii) nanomaterial technology, iii) nanomotors, iv) biomimetic design, and (v) microfluidics. Next section describes futuristic cutting-edge technologies that are gaining momentum in recent years, which furnish highly innovative aspects to biosensing devices. Copyright © 2016 Elsevier B.V. All rights reserved.

Current Trends in Nanomaterial-Based Amperometric Biosensors

PubMed Central

Hayat, Akhtar; Catanante, Gaëlle; Marty, Jean Louis

2014-01-01

The last decade has witnessed an intensive research effort in the field of electrochemical sensors, with a particular focus on the design of amperometric biosensors for diverse analytical applications. In this context, nanomaterial integration in the construction of amperometric biosensors may constitute one of the most exciting approaches. The attractive properties of nanomaterials have paved the way for the design of a wide variety of biosensors based on various electrochemical detection methods to enhance the analytical characteristics. However, most of these nanostructured materials are not explored in the design of amperometric biosensors. This review aims to provide insight into the diverse properties of nanomaterials that can be possibly explored in the construction of amperometric biosensors. PMID:25494347

Design and simulation of MEMS microvalves for silicon photonic biosensor chip

NASA Astrophysics Data System (ADS)

Amemiya, Yoshiteru; Nakashima, Yuuto; Maeda, Jun; Yokoyama, Shin

2018-04-01

For the early and easy diagnosis of diseases, we have proposed a silicon photonic biosensor chip with two kinds of MEMS microvalves for a multiple-item detection system. The driving voltage of the vertical type with the circular-plate capacitor structure and that of the lateral type with the comb-shaped electrode are investigated. From mechanical calculations, the driving voltage of the vertical type is estimated to be 30 V and that of the lateral type to be 15 V. The propagation loss at the intersecting waveguides of arrayed ring-resonator biosensors is also estimated. In the case of optimized intersecting waveguides, more than 67% transmittance of TE-mode light is simulated for the series connection of 20 intersecting waveguides. It is confirmed that it is possible to fabricate an 8 × 12 arrayed biosensor chip in an area of 1 × 1.5 mm2 taking the device size of the microvalves into consideration. We have, for the first time, designed a whole system, including sensors and a fluid channel with MEMS microvalves.

Facile fabrication of a silicon nanowire sensor by two size reduction steps for detection of alpha-fetoprotein biomarker of liver cancer

NASA Astrophysics Data System (ADS)

Binh Pham, Van; ThanhTung Pham, Xuan; Nhat Khoa Phan, Thanh; Thanh Tuyen Le, Thi; Chien Dang, Mau

2015-12-01

We present a facile technique that only uses conventional micro-techniques and two size-reduction steps to fabricate wafer-scale silicon nanowire (SiNW) with widths of 200 nm. Initially, conventional lithography was used to pattern SiNW with 2 μm width. Then the nanowire width was decreased to 200 nm by two size-reduction steps with isotropic wet etching. The fabricated SiNW was further investigated when used with nanowire field-effect sensors. The electrical characteristics of the fabricated SiNW devices were characterized and pH sensitivity was investigated. Then a simple and effective surface modification process was carried out to modify SiNW for subsequent binding of a desired receptor. The complete SiNW-based biosensor was then used to detect alpha-fetoprotein (AFP), one of the medically approved biomarkers for liver cancer diagnosis. Electrical measurements showed that the developed SiNW biosensor could detect AFP with concentrations of about 100 ng mL-1. This concentration is lower than the necessary AFP concentration for liver cancer diagnosis.

Ab initio design of nanostructures for solar energy conversion: a case study on silicon nitride nanowire.

PubMed

Pan, Hui

2014-01-01

Design of novel materials for efficient solar energy conversion is critical to the development of green energy technology. In this work, we present a first-principles study on the design of nanostructures for solar energy harvesting on the basis of the density functional theory. We show that the indirect band structure of bulk silicon nitride is transferred to direct bandgap in nanowire. We find that intermediate bands can be created by doping, leading to enhancement of sunlight absorption. We further show that codoping not only reduces the bandgap and introduces intermediate bands but also enhances the solubility of dopants in silicon nitride nanowires due to reduced formation energy of substitution. Importantly, the codoped nanowire is ferromagnetic, leading to the improvement of carrier mobility. The silicon nitride nanowires with direct bandgap, intermediate bands, and ferromagnetism may be applicable to solar energy harvesting.

A High-Content Assay for Biosensor Validation and for Examining Stimuli that Affect Biosensor Activity.

PubMed

Slattery, Scott D; Hahn, Klaus M

2014-12-01

Biosensors are valuable tools used to monitor many different protein behaviors in vivo. Demand for new biosensors is high, but their development and characterization can be difficult. During biosensor design, it is necessary to evaluate the effects of different biosensor structures on specificity, brightness, and fluorescence responses. By co-expressing the biosensor with upstream proteins that either stimulate or inhibit the activity reported by the biosensor, one can determine the difference between the biosensor's maximally activated and inactivated state, and examine response to specific proteins. We describe here a method for biosensor validation in a 96-well plate format using an automated microscope. This protocol produces dose-response curves, enables efficient examination of many parameters, and unlike cell suspension assays, allows visual inspection (e.g., for cell health and biosensor or regulator localization). Optimization of single-chain and dual-chain Rho GTPase biosensors is addressed, but the assay is applicable to any biosensor that can be expressed or otherwise loaded in adherent cells. The assay can also be used for purposes other than biosensor validation, using a well-characterized biosensor as a readout for effects of upstream molecules. Copyright © 2014 John Wiley & Sons, Inc.

Computational design of co-assembling protein-DNA nanowires

NASA Astrophysics Data System (ADS)

Mou, Yun; Yu, Jiun-Yann; Wannier, Timothy M.; Guo, Chin-Lin; Mayo, Stephen L.

2015-09-01

Biomolecular self-assemblies are of great interest to nanotechnologists because of their functional versatility and their biocompatibility. Over the past decade, sophisticated single-component nanostructures composed exclusively of nucleic acids, peptides and proteins have been reported, and these nanostructures have been used in a wide range of applications, from drug delivery to molecular computing. Despite these successes, the development of hybrid co-assemblies of nucleic acids and proteins has remained elusive. Here we use computational protein design to create a protein-DNA co-assembling nanomaterial whose assembly is driven via non-covalent interactions. To achieve this, a homodimerization interface is engineered onto the Drosophila Engrailed homeodomain (ENH), allowing the dimerized protein complex to bind to two double-stranded DNA (dsDNA) molecules. By varying the arrangement of protein-binding sites on the dsDNA, an irregular bulk nanoparticle or a nanowire with single-molecule width can be spontaneously formed by mixing the protein and dsDNA building blocks. We characterize the protein-DNA nanowire using fluorescence microscopy, atomic force microscopy and X-ray crystallography, confirming that the nanowire is formed via the proposed mechanism. This work lays the foundation for the development of new classes of protein-DNA hybrid materials. Further applications can be explored by incorporating DNA origami, DNA aptamers and/or peptide epitopes into the protein-DNA framework presented here.

Design and fabrication of Ni nanowires having periodically hollow nanostructures.

PubMed

Sada, Takao; Fujigaya, Tsuyohiko; Nakashima, Naotoshi

2014-10-07

We propose a concept for the design and fabrication of metal nanowires having periodically hollow nanostructures inside the pores of an anodic aluminum oxide (AAO) membrane using a sacrificial metal. In this study, nickel (Ni) and silver (Ag) were used as the base metal and the sacrificial metal, respectively. Alternating an applied potential between -0.4 and -1.0 V provided alternatively deposited Ni and Ag segments in a Ni-Ag 'barcode' nanowire with a diameter of 18 or 35 nm. After etching away the Ag segments, we fabricated Ni nanowires with nanopores of 12 ± 5.3 nm. Such nanostructure formation is explained by the formation of a Ni shell layer over the surface of the Ag segments due to the strong affinity of Ni(2+) for the interior surfaces of AAO. The Ni shell layer allows the Ni segments to remain even after dissolution of the Ag segments. Because the electroplating conditions can be easily controlled, we could carefully adjust the size and pitch of the periodically hollow nanospaces. We also describe a method for the fabrication of Ni nanorods by forming an Ag shell instead of a Ni shell on the Ni-Ag barcode nanowire, in which the interior of the AAO surfaces was modified with a compound bearing a thiol group prior to electroplating.

Silicon nanowires reliability and robustness investigation using AFM-based techniques

NASA Astrophysics Data System (ADS)

Bieniek, Tomasz; Janczyk, Grzegorz; Janus, Paweł; Grabiec, Piotr; Nieprzecki, Marek; Wielgoszewski, Grzegorz; Moczała, Magdalena; Gotszalk, Teodor; Buitrago, Elizabeth; Badia, Montserrat F.; Ionescu, Adrian M.

2013-07-01

Silicon nanowires (SiNWs) have undergone intensive research for their application in novel integrated systems such as field effect transistor (FET) biosensors and mass sensing resonators profiting from large surface-to-volume ratios (nano dimensions). Such devices have been shown to have the potential for outstanding performances in terms of high sensitivity, selectivity through surface modification and unprecedented structural characteristics. This paper presents the results of mechanical characterization done for various types of suspended SiNWs arranged in a 3D array. The characterization has been performed using techniques based on atomic force microscopy (AFM). This investigation is a necessary prerequisite for the reliable and robust design of any biosensing system. This paper also describes the applied investigation methodology and reports measurement results aggregated during series of AFM-based tests.

Design and application of a lactulose biosensor.

PubMed

Wu, Jieyuan; Jiang, Peixia; Chen, Wei; Xiong, Dandan; Huang, Linglan; Jia, Junying; Chen, Yuanyuan; Jin, Jian-Ming; Tang, Shuang-Yan

2017-04-07

In this study the repressor of Escherichia coli lac operon, LacI, has been engineered for altered effector specificity. A LacI saturation mutagenesis library was subjected to Fluorescence Activated Cell Sorting (FACS) dual screening. Mutant LacI-L5 was selected and it is specifically induced by lactulose but not by other disaccharides tested (lactose, epilactose, maltose, sucrose, cellobiose and melibiose). LacI-L5 has been successfully used to construct a whole-cell lactulose biosensor which was then applied in directed evolution of cellobiose 2-epimerase (C2E) for elevated lactulose production. The mutant C2E enzyme with ~32-fold enhanced expression level was selected, demonstrating the high efficiency of the lactulose biosensor. LacI-L5 can also be used as a novel regulatory tool. This work explores the potential of engineering LacI for customized molecular biosensors which can be applied in practice.

Single Zno Nanowire-Based Biofet Sensors for Ultrasensitive, Label-Free and Real-Time Detection of Uric Acid

NASA Astrophysics Data System (ADS)

Lin, Pei; Liu, Xi; Yan, Xiaoqin; Kang, Zhuo; Lei, Yang; Zhao, Yanguang

2012-08-01

Qualitative and quantitative detection of biological and chemical species is crucial in many areas, ranging from clinical diagnosis to homeland security. Due to the advantages of ultrahigh sensitivity, label-free, fast readout and easy fabrication over the traditional detection systems, semiconductor nanowire based electronic devices have emerged as a potential platform. In this paper, we fabricated a single ZnO nanowire-based bioFET sensor for the detection of low and high concentration uric acid solution at the same time. The addition of uric acid with the concentrations from 1 pM to 0.5 mM resulted in the electrical conductance changes of up to 227 nS, and the response time turns out to be in the order of millisecond. The ZnO NW biosensor could easily detect as low as 1 pM of the uric acid with 14.7 nS of conductance increase, which implied that the sensitivity of the biosensor can be below the 1pM concentration.

DNA nanotechnology-enabled biosensors.

PubMed

Chao, Jie; Zhu, Dan; Zhang, Yinan; Wang, Lianhui; Fan, Chunhai

2016-02-15

Biosensors employ biological molecules to recognize the target and utilize output elements which can translate the biorecognition event into electrical, optical or mass-sensitive signals to determine the quantities of the target. DNA-based biosensors, as a sub-field to biosensor, utilize DNA strands with short oligonucleotides as probes for target recognition. Although DNA-based biosensors have offered a promising alternative for fast, simple and cheap detection of target molecules, there still exist key challenges including poor stability and reproducibility that hinder their competition with the current gold standard for DNA assays. By exploiting the self-recognition properties of DNA molecules, researchers have dedicated to make versatile DNA nanostructures in a highly rigid, controllable and functionalized manner, which offers unprecedented opportunities for developing DNA-based biosensors. In this review, we will briefly introduce the recent advances on design and fabrication of static and dynamic DNA nanostructures, and summarize their applications for fabrication and functionalization of DNA-based biosensors. Copyright © 2015 Elsevier B.V. All rights reserved.

The effect of nanowire length and diameter on the properties of transparent, conducting nanowire films

NASA Astrophysics Data System (ADS)

Bergin, Stephen M.; Chen, Yu-Hui; Rathmell, Aaron R.; Charbonneau, Patrick; Li, Zhi-Yuan; Wiley, Benjamin J.

2012-03-01

This article describes how the dimensions of nanowires affect the transmittance and sheet resistance of a random nanowire network. Silver nanowires with independently controlled lengths and diameters were synthesized with a gram-scale polyol synthesis by controlling the reaction temperature and time. Characterization of films composed of nanowires of different lengths but the same diameter enabled the quantification of the effect of length on the conductance and transmittance of silver nanowire films. Finite-difference time-domain calculations were used to determine the effect of nanowire diameter, overlap, and hole size on the transmittance of a nanowire network. For individual nanowires with diameters greater than 50 nm, increasing diameter increases the electrical conductance to optical extinction ratio, but the opposite is true for nanowires with diameters less than this size. Calculations and experimental data show that for a random network of nanowires, decreasing nanowire diameter increases the number density of nanowires at a given transmittance, leading to improved connectivity and conductivity at high transmittance (>90%). This information will facilitate the design of transparent, conducting nanowire films for flexible displays, organic light emitting diodes and thin-film solar cells.This article describes how the dimensions of nanowires affect the transmittance and sheet resistance of a random nanowire network. Silver nanowires with independently controlled lengths and diameters were synthesized with a gram-scale polyol synthesis by controlling the reaction temperature and time. Characterization of films composed of nanowires of different lengths but the same diameter enabled the quantification of the effect of length on the conductance and transmittance of silver nanowire films. Finite-difference time-domain calculations were used to determine the effect of nanowire diameter, overlap, and hole size on the transmittance of a nanowire network. For

Zinc oxide inverse opal enzymatic biosensor

NASA Astrophysics Data System (ADS)

You, Xueqiu; Pikul, James H.; King, William P.; Pak, James J.

2013-06-01

We report ZnO inverse opal- and nanowire (NW)-based enzymatic glucose biosensors with extended linear detection ranges. The ZnO inverse opal sensors have 0.01-18 mM linear detection range, which is 2.5 times greater than that of ZnO NW sensors and 1.5 times greater than that of other reported ZnO sensors. This larger range is because of reduced glucose diffusivity through the inverse opal geometry. The ZnO inverse opal sensors have an average sensitivity of 22.5 μA/(mM cm2), which diminished by 10% after 35 days, are more stable than ZnO NW sensors whose sensitivity decreased by 10% after 7 days.

Size-dependent Young’s modulus in ZnO nanowires with strong surface atomic bonds

NASA Astrophysics Data System (ADS)

Fan, Shiwen; Bi, Sheng; Li, Qikun; Guo, Qinglei; Liu, Junshan; Ouyang, Zhongliang; Jiang, Chengming; Song, Jinhui

2018-03-01

The mechanical properties of size-dependent nanowires are important in nano-electro-mechanical systems (NEMSs), and have attracted much research interest. Characterization of the size effect of nanowires in atmosphere directly to broaden their practical application instead of just in high vacuum situations, as reported previously, is desperately needed. In this study, we systematically studied the Young’s modulus of vertical ZnO nanowires in atmosphere. The diameters ranged from 48 nm to 239 nm with a resonance method using non-contact atomic force microscopy. The values of Young’s modulus in atmosphere present extremely strong increasing tendency with decreasing diameter of nanowire due to stronger surface atomic bonds compared with that in vacuum. A core-shell model for nanowires is proposed to explore the Young’s modulus enhancement in atmosphere, which is correlated with atoms of oxygen occurring near the nanowire surface. The modified model is more accurate for analyzing the mechanical behavior of nanowires in atmosphere compared with the model in vacuum. Furthermore, it is possible to use this characterization method to measure the size-related elastic properties of similar wire-sharp nanomaterials in atmosphere and estimate the corresponding mechanical behavior. The study of the size-dependent Young’s modulus in ZnO nanowires in atmosphere will improve the understanding of the mechanical properties of nanomaterials as well as providing guidance for applications in NEMSs, nanogenerators, biosensors and other related areas.

Nanochannels Photoelectrochemical Biosensor.

PubMed

Zhang, Nan; Ruan, Yi-Fan; Zhang, Li-Bin; Zhao, Wei-Wei; Xu, Jing-Juan; Chen, Hong-Yuan

2018-02-06

Nanochannels have brought new opportunities for biosensor development. Herein, we present the novel concept of a nanochannels photoelectrochemical (PEC) biosensor based on the integration of a unique Cu x O-nanopyramid-islands (NPIs) photocathode, an anodic aluminum oxide (AAO) membrane, and alkaline phosphatase (ALP) catalytic chemistry. The Cu x O-NPIs photocathode possesses good performance, and further assembly with AAO yields a designed architecture composed of vertically aligned, highly ordered nanoarrays on top of the Cu x O-NPIs film. After biocatalytic precipitation (BCP) was stimulated within the channels, the biosensor was used for the successful detection of ALP activity. This study has not only provided a novel paradigm for an unconventional nanochannels PEC biosensor, which can be used for general bioanalytical purposes, but also indicated that the new concept of nanochannel-semiconductor heterostructures is a step toward innovative biomedical applications.

Plasmonic Biosensor Based on Vertical Arrays of Gold Nanoantennas.

PubMed

Klinghammer, Stephanie; Uhlig, Tino; Patrovsky, Fabian; Böhm, Matthias; Schütt, Julian; Pütz, Nils; Baraban, Larysa; Eng, Lukas M; Cuniberti, Gianaurelio

2018-06-25

Implementing large arrays of gold nanowires as functional elements of a plasmonic biosensor is an important task for future medical diagnostic applications. Here we present a microfluidic-channel-integrated sensor for the label-free detection of biomolecules, relying on localized surface plasmon resonances. Large arrays (∼1 cm 2 ) of vertically aligned and densely packed gold nanorods to receive, locally confine, and amplify the external optical signal are used to allow for reliable biosensing. We accomplish this by monitoring the change of the optical nanostructure resonance in the presence of biomolecules within the tight focus area above the nanoantennas, combined with a surface treatment of the nanowires for a specific binding of the target molecules. As a first application, we detect the binding kinetics of two distinct DNA strands as well as the following hybridization of two complementary strands (cDNA) with different lengths (25 and 100 bp). Upon immobilization, a redshift of 1 nm was detected; further backfilling and hybridization led to a peak shift of additional 2 and 5 nm for 25 and 100 bp, respectively. We believe that this work gives deeper insight into the functional understanding and technical implementation of a large array of gold nanowires for future medical applications.

A bio-inspired design of live cell biosensors

NASA Astrophysics Data System (ADS)

Marcek Chorvatova, A.; Teplicky, T.; Pavlinska, Z.; Kronekova, Z.; Trelova, D.; Razga, F.; Nemethova, V.; Uhelska, L.; Lacik, I.; Chorvat, D.

2018-02-01

The last decade has witnessed a rapid growth of nanoscale-oriented biosensors that becomes one of the most promising and rapidly growing areas of modern research. Despite significant advancements in conception of such biosensors, most are based at evaluation of molecular, or protein interactions. It is however becoming increasingly evident that functionality of a living system does not reside in genome or in individual proteins, as no real biological functionality is expressed at these levels. Instead, to comprehend the true functioning of a biological system, it is essential to understand the integrative physiological behavior of the complex molecular interactions in their natural environment and precise spatio-temporal topology. In this contribution we therefore present a new concept for creation of biosensors, bio-inspired from true functioning of living cells, while monitoring their endogenous fluorescence, or autofluorescence.

Copper nanowire coated carbon fibers as efficient substrates for detecting designer drugs using SERS.

PubMed

Halouzka, Vladimir; Halouzkova, Barbora; Jirovsky, David; Hemzal, Dusan; Ondra, Peter; Siranidi, Eirini; Kontos, Athanassios G; Falaras, Polycarpos; Hrbac, Jan

2017-04-01

Miniature Surface Enhanced Raman Scattering (SERS) sensors were fabricated by coating the carbon fiber microelectrodes with copper nanowires. The coating procedure, based on anodizing the copper wire in ultrapure water followed by cathodic deposition of the anode-derived material onto carbon fiber electrodes, provides a "clean" copper nanowire network. The developed miniature (10µm in diameter and 2mm in length) and nanoscopically rough SERS substrates are applicable in drug sensing, as shown by the detection and resolving of a range of seized designer drugs in trace amounts (microliter volumes of 10 -10 -10 -12 M solutions). The copper nanowire modified carbon microfiber substrates could also find further applications in biomedical and environmental sensing. Copyright © 2016 Elsevier B.V. All rights reserved.

Semi-autonomous inline water analyzer: design of a common light detector for bacterial, phage, and immunological biosensors.

PubMed

Descamps, Elodie C T; Meunier, Damien; Brutesco, Catherine; Prévéral, Sandra; Franche, Nathalie; Bazin, Ingrid; Miclot, Bertrand; Larosa, Philippe; Escoffier, Camille; Fantino, Jean-Raphael; Garcia, Daniel; Ansaldi, Mireille; Rodrigue, Agnès; Pignol, David; Cholat, Pierre; Ginet, Nicolas

2017-01-01

The use of biosensors as sensitive and rapid alert systems is a promising perspective to monitor accidental or intentional environmental pollution, but their implementation in the field is limited by the lack of adapted inline water monitoring devices. We describe here the design and initial qualification of an analyzer prototype able to accommodate three types of biosensors based on entirely different methodologies (immunological, whole-cell, and bacteriophage biosensors), but whose responses rely on the emission of light. We developed a custom light detector and a reaction chamber compatible with the specificities of the three systems and resulting in statutory detection limits. The water analyzer prototype resulting from the COMBITOX project can be situated at level 4 on the Technology Readiness Level (TRL) scale and this technical advance paves the way to the use of biosensors on-site.

Simplifying Nanowire Hall Effect Characterization by Using a Three-Probe Device Design.

PubMed

Hultin, Olof; Otnes, Gaute; Samuelson, Lars; Storm, Kristian

2017-02-08

Electrical characterization of nanowires is a time-consuming and challenging task due to the complexity of single nanowire device fabrication and the difficulty in interpreting the measurements. We present a method to measure Hall effect in nanowires using a three-probe device that is simpler to fabricate than previous four-probe nanowire Hall devices and allows characterization of nanowires with smaller diameter. Extraction of charge carrier concentration from the three-probe measurements using an analytical model is discussed and compared to simulations. The validity of the method is experimentally verified by a comparison between results obtained with the three-probe method and results obtained using four-probe nanowire Hall measurements. In addition, a nanowire with a diameter of only 65 nm is characterized to demonstrate the capabilities of the method. The three-probe Hall effect method offers a relatively fast and simple, yet accurate way to quantify the charge carrier concentration in nanowires and has the potential to become a standard characterization technique for nanowires.

How to Design a Biosensor

PubMed Central

Ward, W. Kenneth

2007-01-01

Amperometric sensors for continuous glucose monitoring could prevent acute and chronic complications of diabetes, but research is needed to improve accuracy and stability. In designing sensors, interference from non-glucose analytes can be minimized by use of filtration membranes or electron transfer mediators that allow polarization at low potentials. If oxygen is required for the enzymatic reaction with glucose, then the outer permselective membrane must have substantial oxygen permeability. For this reason, during development of permselective membranes, permeability studies (such as performed by Tipnis and colleagues in this issue) can be used to measure transport of glucose and oxygen and optimize membrane structure. Tipnis and colleagues present a novel biosensor based with separate layers for glucose-oxygen permselectivity, enzymatic conversion, and avoidance of interference. They also address sensor stability, in part by comparing sensor function during ascending vs descending glucose levels. By measuring the difference, they were able to minimize this aspect of instability (hysterisis), which assisted them in selecting a promising permselective membrane based on iron and humic acid. PMID:19888407

How to design a biosensor.

PubMed

Ward, W Kenneth

2007-03-01

Amperometric sensors for continuous glucose monitoring could prevent acute and chronic complications of diabetes, but research is needed to improve accuracy and stability. In designing sensors, interference from non-glucose analytes can be minimized by use of filtration membranes or electron transfer mediators that allow polarization at low potentials. If oxygen is required for the enzymatic reaction with glucose, then the outer permselective membrane must have substantial oxygen permeability. For this reason, during development of permselective membranes, permeability studies (such as performed by Tipnis and colleagues in this issue) can be used to measure transport of glucose and oxygen and optimize membrane structure. Tipnis and colleagues present a novel biosensor based with separate layers for glucose-oxygen permselectivity, enzymatic conversion, and avoidance of interference. They also address sensor stability, in part by comparing sensor function during ascending vs descending glucose levels. By measuring the difference, they were able to minimize this aspect of instability (hysterisis), which assisted them in selecting a promising permselective membrane based on iron and humic acid.

Design and Fabrication of nanowire-grid polarizer in near-infrared broadband

NASA Astrophysics Data System (ADS)

Jin, Qiufeng; Liu, Quan; Wu, Jianhong; Cheng, Yu

2012-11-01

The infrared polarizers are widely used in the infrared imaging systems as the core components, such as infrared stealth, target acquisition and mine detection, automobile night-vision instrument and other systems. For the requirements of near-infrared imaging systems, a nanowire-grid is designed by Finite Difference Time Domain (FDTD) method. Herein, considering the high reflection of metal aluminum in the manufacturing process, we propose a structure with aluminum-copper nanowire-grid. FDTD method is adapted to analyze the effects of the thickness of aluminumcopper in different combinations on the TM and TE polarization transmission efficiency as well as the extinction ratio when the grating's period is 300nm. Numerical results and theoretical analysis show that: the reflection on the substrate is suppressed with the optimal thickness of the Cu layer. Considering the resist-substrate reflectivity and the final performance of the polarizer, the structure with an 120nm Al layer, and a 50nm anti-reflection Cu layer is chosen; and the TM transmission efficiency is more than 71%, and the extinction ratio is more than 25dB. At last we used Holographic lithography and IBE to fabricate a prototype of the nanowire-grid.

Biosensor-based engineering of biosynthetic pathways

DOE PAGES

Rogers, Jameson K.; Taylor, Noah D.; Church, George M.

2016-03-18

Biosynthetic pathways provide an enzymatic route from inexpensive renewable resources to valuable metabolic products such as pharmaceuticals and plastics. However, designing these pathways is challenging due to the complexities of biology. Advances in the design and construction of genetic variants has enabled billions of cells, each possessing a slightly different metabolic design, to be rapidly generated. However, our ability to measure the quality of these designs lags by several orders of magnitude. Recent research has enabled cells to report their own success in chemical production through the use of genetically encoded biosensors. A new engineering discipline is emerging around themore » creation and application of biosensors. Biosensors, implemented in selections and screens to identify productive cells, are paving the way for a new era of biotechnological progress.« less

Design and application of fiber optic evanescent wave biosensor

NASA Astrophysics Data System (ADS)

Huang, Huijie; Zhai, Junhui; Zhao, Yongkai; Yang, Ruifu; Ren, Bingqiang; Cheng, Zhaogu; Du, Longlong; Lu, Dunwu

2003-12-01

A fiber-optic biosensor is developed based on the principle of evanescent wave while light propagates in optical fiber. The biosensor uses a red laser diode at 636.85 nm for exciting Cy5 fluorescent dye. Sensitivity limit of 0.01 nnmol/l is obtained from the detection of serial Cy5 solutions with various concentrations. In log-to-log plot, excellent linear response characteristic is seen in the Cy5 concentrations ranging from 0.01 nmlo/l to 100 nmol/l. And a good result of signal-to-noise ratio of 4.61 is obtained when the biosensor is used to measure Legionella pneumophila solution of 0.01 μmol/l. All the results are comparable with those that are obtained by a commercial biochip scanner GeneTAC 1000.

TiO2 nanowire-templated hierarchical nanowire network as water-repelling coating

NASA Astrophysics Data System (ADS)

Hang, Tian; Chen, Hui-Jiuan; Xiao, Shuai; Yang, Chengduan; Chen, Meiwan; Tao, Jun; Shieh, Han-ping; Yang, Bo-ru; Liu, Chuan; Xie, Xi

2017-12-01

Extraordinary water-repelling properties of superhydrophobic surfaces make them novel candidates for a great variety of potential applications. A general approach to achieve superhydrophobicity requires low-energy coating on the surface and roughness on nano- and micrometre scale. However, typical construction of superhydrophobic surfaces with micro-nano structure through top-down fabrication is restricted by sophisticated fabrication techniques and limited choices of substrate materials. Micro-nanoscale topographies templated by conventional microparticles through surface coating may produce large variations in roughness and uncontrollable defects, resulting in poorly controlled surface morphology and wettability. In this work, micro-nanoscale hierarchical nanowire network was fabricated to construct self-cleaning coating using one-dimensional TiO2 nanowires as microscale templates. Hierarchical structure with homogeneous morphology was achieved by branching ZnO nanowires on the TiO2 nanowire backbones through hydrothermal reaction. The hierarchical nanowire network displayed homogeneous micro/nano-topography, in contrast to hierarchical structure templated by traditional microparticles. This hierarchical nanowire network film exhibited high repellency to both water and cell culture medium after functionalization with fluorinated organic molecules. The hierarchical structure templated by TiO2 nanowire coating significantly increased the surface superhydrophobicity compared to vertical ZnO nanowires with nanotopography alone. Our results demonstrated a promising strategy of using nanowires as microscale templates for the rational design of hierarchical coatings with desired superhydrophobicity that can also be applied to various substrate materials.

TiO2 nanowire-templated hierarchical nanowire network as water-repelling coating

PubMed Central

Hang, Tian; Chen, Hui-Jiuan; Xiao, Shuai; Yang, Chengduan; Chen, Meiwan; Tao, Jun; Shieh, Han-ping; Yang, Bo-ru; Liu, Chuan

2017-01-01

Extraordinary water-repelling properties of superhydrophobic surfaces make them novel candidates for a great variety of potential applications. A general approach to achieve superhydrophobicity requires low-energy coating on the surface and roughness on nano- and micrometre scale. However, typical construction of superhydrophobic surfaces with micro-nano structure through top-down fabrication is restricted by sophisticated fabrication techniques and limited choices of substrate materials. Micro-nanoscale topographies templated by conventional microparticles through surface coating may produce large variations in roughness and uncontrollable defects, resulting in poorly controlled surface morphology and wettability. In this work, micro-nanoscale hierarchical nanowire network was fabricated to construct self-cleaning coating using one-dimensional TiO2 nanowires as microscale templates. Hierarchical structure with homogeneous morphology was achieved by branching ZnO nanowires on the TiO2 nanowire backbones through hydrothermal reaction. The hierarchical nanowire network displayed homogeneous micro/nano-topography, in contrast to hierarchical structure templated by traditional microparticles. This hierarchical nanowire network film exhibited high repellency to both water and cell culture medium after functionalization with fluorinated organic molecules. The hierarchical structure templated by TiO2 nanowire coating significantly increased the surface superhydrophobicity compared to vertical ZnO nanowires with nanotopography alone. Our results demonstrated a promising strategy of using nanowires as microscale templates for the rational design of hierarchical coatings with desired superhydrophobicity that can also be applied to various substrate materials. PMID:29308265

Biosensors in Clinical Practice: Focus on Oncohematology

PubMed Central

Fracchiolla, Nicola S.; Artuso, Silvia; Cortelezzi, Agostino

2013-01-01

Biosensors are devices that are capable of detecting specific biological analytes and converting their presence or concentration into some electrical, thermal, optical or other signal that can be easily analysed. The first biosensor was designed by Clark and Lyons in 1962 as a means of measuring glucose. Since then, much progress has been made and the applications of biosensors are today potentially boundless. This review is limited to their clinical applications, particularly in the field of oncohematology. Biosensors have recently been developed in order to improve the diagnosis and treatment of patients affected by hematological malignancies, such as the biosensor for assessing the in vitro pre-treatment efficacy of cytarabine in acute myeloid leukemia, and the fluorescence resonance energy transfer-based biosensor for assessing the efficacy of imatinib in chronic myeloid leukemia. The review also considers the challenges and future perspectives of biosensors in clinical practice. PMID:23673681

Gold nanowire assembling architecture for H2O2 electrochemical sensor.

PubMed

Guo, Shaojun; Wen, Dan; Dong, Shaojun; Wang, Erkang

2009-02-15

Morphological control of nanomaterials is of great interest due to their size and shape-dependent chemical and physical properties and very important applications in many fields such as biomedicine, sensors, electronics and others. In this paper, we reported a simple strategy for synthesizing gold nanowire assembling architecture at room temperature. It is found that two important factors, the proper volume ratio of ethanol to water and poly(vinyl pyrrolidone) (PVP), will play important roles in synthesizing flower-like short gold nanowire assembling spheres. Furthermore, the obtained flower-like gold assembling spheres with high surface-to-volume ratio have been employed as enhancing materials for electrochemical sensing H(2)O(2). The present electrochemical sensing platform exhibited good electrocatalytic activity towards the reduction of H(2)O(2). The detection limit for H(2)O(2) was found to be 1.2 microM, which was lower than certain enzyme-based biosensors.

Simulation study on discrete charge effects of SiNW biosensors according to bound target position using a 3D TCAD simulator.

PubMed

Chung, In-Young; Jang, Hyeri; Lee, Jieun; Moon, Hyunggeun; Seo, Sung Min; Kim, Dae Hwan

2012-02-17

We introduce a simulation method for the biosensor environment which treats the semiconductor and the electrolyte region together, using the well-established semiconductor 3D TCAD simulator tool. Using this simulation method, we conduct electrostatic simulations of SiNW biosensors with a more realistic target charge model where the target is described as a charged cube, randomly located across the nanowire surface, and analyze the Coulomb effect on the SiNW FET according to the position and distribution of the target charges. The simulation results show the considerable variation in the SiNW current according to the bound target positions, and also the dependence of conductance modulation on the polarity of target charges. This simulation method and the results can be utilized for analysis of the properties and behavior of the biosensor device, such as the sensing limit or the sensing resolution.

Optical biosensors.

PubMed

Damborský, Pavel; Švitel, Juraj; Katrlík, Jaroslav

2016-06-30

Optical biosensors represent the most common type of biosensor. Here we provide a brief classification, a description of underlying principles of operation and their bioanalytical applications. The main focus is placed on the most widely used optical biosensors which are surface plasmon resonance (SPR)-based biosensors including SPR imaging and localized SPR. In addition, other optical biosensor systems are described, such as evanescent wave fluorescence and bioluminescent optical fibre biosensors, as well as interferometric, ellipsometric and reflectometric interference spectroscopy and surface-enhanced Raman scattering biosensors. The optical biosensors discussed here allow the sensitive and selective detection of a wide range of analytes including viruses, toxins, drugs, antibodies, tumour biomarkers and tumour cells. © 2016 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Fiber optic choline biosensor

NASA Astrophysics Data System (ADS)

Wang, Hong; Cao, Xiaojian; Jia, Ke; Chai, Xueting; Lu, Hua; Lu, Zuhong

2001-10-01

A fiber optic fluorescence biosensor for choline is introduced in this paper. Choline is an important neurotransmitter in mammals. Due to the growing needs for on-site clinical monitoring of the choline, much effect has been devoted to develop choline biosensors. Fiber-optic fluorescence biosensors have many advantages, including miniaturization, flexibility, and lack of electrical contact and interference. The choline fiber-optic biosensor we designed implemented a bifurcated fiber to perform fluorescence measurements. The light of the blue LED is coupled into one end of the fiber as excitation and the emission spectrum from sensing film is monitored by fiber-spectrometer (S2000, Ocean Optics) through the other end of the fiber. The sensing end of the fiber is coated with Nafion film dispersed with choline oxidase and oxygen sensitive luminescent Ru(II) complex (Tris(2,2'-bipyridyl)dichlororuthenium(II), hexahydrate). Choline oxidase catalyzes the oxidation of choline to betaine and hydrogen peroxide while consuming oxygen. The fluorescence intensity of oxygen- sensitive Ru(II) are related to the choline concentration. The response of the fiber-optic sensor in choline solution is represented and discussed. The result indicates a low-cost, high-performance, portable choline biosensor.

Device considerations for development of conductance-based biosensors

PubMed Central

Lee, Kangho; Nair, Pradeep R.; Scott, Adina; Alam, Muhammad A.; Janes, David B.

2009-01-01

Design and fabrication of electronic biosensors based on field-effect-transistor (FET) devices require understanding of interactions between semiconductor surfaces and organic biomolecules. From this perspective, we review practical considerations for electronic biosensors with emphasis on molecular passivation effects on FET device characteristics upon immobilization of organic molecules and an electrostatic model for FET-based biosensors. PMID:24753627

Optimal design of aperiodic, vertical silicon nanowire structures for photovoltaics.

PubMed

Lin, Chenxi; Povinelli, Michelle L

2011-09-12

We design a partially aperiodic, vertically-aligned silicon nanowire array that maximizes photovoltaic absorption. The optimal structure is obtained using a random walk algorithm with transfer matrix method based electromagnetic forward solver. The optimal, aperiodic structure exhibits a 2.35 times enhancement in ultimate efficiency compared to its periodic counterpart. The spectral behavior mimics that of a periodic array with larger lattice constant. For our system, we find that randomly-selected, aperiodic structures invariably outperform the periodic array.

Step-gate polysilicon nanowires field effect transistor compatible with CMOS technology for label-free DNA biosensor.

PubMed

Wenga, G; Jacques, E; Salaün, A-C; Rogel, R; Pichon, L; Geneste, F

2013-02-15

Currently, detection of DNA hybridization using fluorescence-based detection technique requires expensive optical systems and complex bioinformatics tools. Hence, the development of new low cost devices that enable direct and highly sensitive detection stimulates a lot of research efforts. Particularly, devices based on silicon nanowires are emerging as ultrasensitive electrical sensors for the direct detection of biological species thanks to their high surface to volume ratio. In this study, we propose innovative devices using step-gate polycrystalline silicon nanowire FET (poly-Si NW FETs), achieved with simple and low cost fabrication process, and used as ultrasensitive electronic sensor for DNA hybridization. The poly-SiNWs are synthesized using the sidewall spacer formation technique. The detailed fabrication procedure for a step-gate NWFET sensor is described in this paper. No-complementary and complementary DNA sequences were clearly discriminated and detection limit to 1 fM range is observed. This first result using this nano-device is promising for the development of low cost and ultrasensitive polysilicon nanowires based DNA sensors compatible with the CMOS technology. Copyright © 2012 Elsevier B.V. All rights reserved.

Understanding InP Nanowire Array Solar Cell Performance by Nanoprobe-Enabled Single Nanowire Measurements.

PubMed

Otnes, Gaute; Barrigón, Enrique; Sundvall, Christian; Svensson, K Erik; Heurlin, Magnus; Siefer, Gerald; Samuelson, Lars; Åberg, Ingvar; Borgström, Magnus T

2018-05-09

III-V solar cells in the nanowire geometry might hold significant synthesis-cost and device-design advantages as compared to thin films and have shown impressive performance improvements in recent years. To continue this development there is a need for characterization techniques giving quick and reliable feedback for growth development. Further, characterization techniques which can improve understanding of the link between nanowire growth conditions, subsequent processing, and solar cell performance are desired. Here, we present the use of a nanoprobe system inside a scanning electron microscope to efficiently contact single nanowires and characterize them in terms of key parameters for solar cell performance. Specifically, we study single as-grown InP nanowires and use electron beam induced current characterization to understand the charge carrier collection properties, and dark current-voltage characteristics to understand the diode recombination characteristics. By correlating the single nanowire measurements to performance of fully processed nanowire array solar cells, we identify how the performance limiting parameters are related to growth and/or processing conditions. We use this understanding to achieve a more than 7-fold improvement in efficiency of our InP nanowire solar cells, grown from a different seed particle pattern than previously reported from our group. The best cell shows a certified efficiency of 15.0%; the highest reported value for a bottom-up synthesized InP nanowire solar cell. We believe the presented approach have significant potential to speed-up the development of nanowire solar cells, as well as other nanowire-based electronic/optoelectronic devices.

Recent Trends in Biosensors

NASA Astrophysics Data System (ADS)

Karube, Isao

The determination of organic compounds in foods is very important in food industries. A various compounds are contained in foods, selective determination methods are required for food processing and analysis. Electrochemical monitoring devices (biosensors) employing immobilized biocatalysts such as immobilized enzymes, organelles, microorganisms, and tissue have definite advantages. The enzyme Sensors consisted of immobilized enzymes and electrochemical devices. Enzyme sensors could be used for the determination of sugars, amino acids, organic acids, alcohols, lipids, nucleic acid derivatives, etc.. Furthermore, a multifunctional biosensor for the determination of several compounds has been developed for food processing. On the other hand, microbial sensors consisted of immobilized microorganisms and electrodes have been used for industrial and environmental analysis. Microbial sensors were applied for the determination of sugars, organic acids, alcohols, amino acids, mutagens, me thane, ammonia, and BOD. Furthermore, micro-biosensors using immobilized biocatalysts and ion sensitive field effect transistor or microelectrodes prepared by silicon fabrication technologies have been developed for medical ap. plication and food processing. This review summarizes the design and application of biosensors.

Bioelectrochemical interface engineering: toward the fabrication of electrochemical biosensors, biofuel cells, and self-powered logic biosensors.

PubMed

Zhou, Ming; Dong, Shaojun

2011-11-15

Over the past decade, researchers have devoted considerable attention to the integration of living organisms with electronic elements to yield bioelectronic devices. Not only is the integration of DNA, enzymes, or whole cells with electronics of scientific interest, but it has many versatile potential applications. Researchers are using these ideas to fabricate biosensors for analytical applications and to assemble biofuel cells (BFCs) and biomolecule-based devices. Other research efforts include the development of biocomputing systems for information processing. In this Account, we focus on our recent progress in engineering at the bioelectrochemical interface (BECI) for the rational design and construction of important bioelectronic devices, ranging from electrochemical (EC-) biosensors to BFCs, and self-powered logic biosensors. Hydrogels and sol-gels provide attractive materials for the immobilization of enzymes because they make EC-enzyme biosensors stable and even functional in extreme environments. We use a layer-by-layer (LBL) self-assembly technique to fabricate multicomponent thin films on the BECI at the nanometer scale. Additionally, we demonstrate how carbon nanomaterials have paved the way for new and improved EC-enzyme biosensors. In addition to the widely reported BECI-based electrochemical impedance spectroscopy (EIS)-type aptasensors, we integrate the LBL technique with our previously developed "solid-state probe" technique for redox probes immobilization on electrode surfaces to design and fabricate BECI-based differential pulse voltammetry (DPV)-type aptasensors. BFCs can directly harvest energy from ambient biofuels as green energy sources, which could lead to their application as simple, flexible, and portable power sources. Porous materials provide favorable microenvironments for enzyme immobilization, which can enhance BFC power output. Furthermore, by introducing aptamer-based logic systems to BFCs, such systems could be applied as self

Nanowire Aptasensors for Electrochemical Detection of Cell-Secreted Cytokines.

PubMed

Liu, Ying; Rahimian, Ali; Krylyuk, Sergiy; Vu, Tam; Crulhas, Bruno; Stybayeva, Gulnaz; Imanbekova, Meruyert; Shin, Dong-Sik; Davydov, Albert; Revzin, Alexander

2017-11-22

Cytokines are small proteins secreted by immune cells in response to pathogens/infections; therefore, these proteins can be used in diagnosing infectious diseases. For example, release of a cytokine interferon (IFN)-γ from T-cells is used for blood-based diagnosis of tuberculosis (TB). Our lab has previously developed an atpamer-based electrochemical biosensor for rapid and sensitive detection of IFN-γ. In this study, we explored the use of silicon nanowires (NWs) as a way to create nanostructured electrodes with enhanced sensitivity for IFN-γ. Si NWs were covered with gold and were further functionalized with thiolated aptamers specific for IFN-γ. Aptamer molecules were designed to form a hairpin and in addition to terminal thiol groups contained redox reporter molecules methylene blue. Binding of analyte to aptamer-modified NWs (termed here nanowire aptasensors) inhibited electron transfer from redox reporters to the electrode and caused electrochemical redox signal to decrease. In a series of experiments we demonstrate that NW aptasensors responded 3× faster and were 2× more sensitive to IFN-γ compared to standard flat electrodes. Most significantly, NW aptasensors allowed detection of IFN-γ from as few as 150 T-cells/mL while ELISA did not pick up signal from the same number of cells. One of the challenges faced by ELISA-based TB diagnostics is poor performance in patients whose T-cell numbers are low, typically HIV patients. Therefore, NW aptasensors developed here may be used in the future for more sensitive monitoring of IFN-γ responses in patients coinfected with HIV/TB.

Design and synthesis of diverse functional kinked nanowire structures for nanoelectronic bioprobes.

PubMed

Xu, Lin; Jiang, Zhe; Qing, Quan; Mai, Liqiang; Zhang, Qingjie; Lieber, Charles M

2013-02-13

Functional kinked nanowires (KNWs) represent a new class of nanowire building blocks, in which functional devices, for example, nanoscale field-effect transistors (nanoFETs), are encoded in geometrically controlled nanowire superstructures during synthesis. The bottom-up control of both structure and function of KNWs enables construction of spatially isolated point-like nanoelectronic probes that are especially useful for monitoring biological systems where finely tuned feature size and structure are highly desired. Here we present three new types of functional KNWs including (1) the zero-degree KNW structures with two parallel heavily doped arms of U-shaped structures with a nanoFET at the tip of the "U", (2) series multiplexed functional KNW integrating multi-nanoFETs along the arm and at the tips of V-shaped structures, and (3) parallel multiplexed KNWs integrating nanoFETs at the two tips of W-shaped structures. First, U-shaped KNWs were synthesized with separations as small as 650 nm between the parallel arms and used to fabricate three-dimensional nanoFET probes at least 3 times smaller than previous V-shaped designs. In addition, multiple nanoFETs were encoded during synthesis in one of the arms/tip of V-shaped and distinct arms/tips of W-shaped KNWs. These new multiplexed KNW structures were structurally verified by optical and electron microscopy of dopant-selective etched samples and electrically characterized using scanning gate microscopy and transport measurements. The facile design and bottom-up synthesis of these diverse functional KNWs provides a growing toolbox of building blocks for fabricating highly compact and multiplexed three-dimensional nanoprobes for applications in life sciences, including intracellular and deep tissue/cell recordings.

Ultrasensitive electrochemical detection of avian influenza A (H7N9) virus DNA based on isothermal exponential amplification coupled with hybridization chain reaction of DNAzyme nanowires.

PubMed

Yu, Yanyan; Chen, Zuanguang; Jian, Wensi; Sun, Duanping; Zhang, Beibei; Li, Xinchun; Yao, Meicun

2015-02-15

In this work, a simple and label-free electrochemical biosensor with duel amplification strategy was developed for DNA detection based on isothermal exponential amplification (EXPAR) coupled with hybridization chain reaction (HCR) of DNAzymes nanowires. Through rational design, neither the primer nor the DNAzymes containing molecular beacons (MBs) could react with the duplex probe which were fixed on the electrode surface. Once challenged with target, the duplex probe cleaved and triggered the EXPAR mediated target recycle and regeneration circles as well as the HCR process. As a result, a greater amount of targets were generated to cleave the duplex probes. Subsequently, the nanowires consisting of the G-quadruplex units were self-assembled through hybridization with the strand fixed on the electrode surface. In the presence of hemin, the resulting catalytic G-quadruplex-hemin HRP-mimicking DNAzymes were formed. Electrochemical signals can be obtained by measuring the increase in reduction current of oxidized 3.3',5.5'-tetramethylbenzidine sulfate (TMB), which was generated by DNAzyme in the presence of H2O2. This method exhibited ultrahigh sensitivity towards avian influenza A (H7N9) virus DNA sequence with detection limits of 9.4 fM and a detection range of 4 orders of magnitude. The biosensor was also capable of discriminating single-nucleotide difference among concomitant DNA sequences and performed well in spiked cell lysates. Copyright © 2014 Elsevier B.V. All rights reserved.

Design, implementation, and application of a microresonator platform for measuring energy dissipation by internal friction in nanowires.

PubMed

Das, Kaushik; Sosale, Guruprasad; Vengallatore, Srikar

2012-12-21

Accurate measurements of internal friction in nanowires are required for the rational design of high-Q resonators used in nanoelectromechanical systems and for fundamental studies of nanomechanical behavior. However, measuring internal friction is challenging because of the difficulties associated with identifying the contributions of material dissipation to structural damping. Here, we present an approach for overcoming these difficulties by using a composite microresonator platform that is calibrated against the ultimate limits of thermoelastic damping. The platform consists of an array of nanowires patterned at the root of a low-loss single-crystal silicon microcantilever. The structure is processed using a lift-off technique, implemented using electron-beam lithography, to achieve excellent control over the size, alignment, dispersion and location of the nanowire array. As the first application of this platform, we measured internal friction at room temperature in aluminum nanowires that ranged from 50 to 100 nm in thickness and 100 to 400 nm in width. Internal friction is ~0.03 at frequencies of 6.5-21 kHz. Transmission electron microscopy of the nanocrystalline grain structure, and comparison with previously measured values of internal friction in continuous thin films of aluminum, suggest that grain-boundary sliding is a major source of internal friction in these nanowires.

Controlling Kink Geometry in Nanowires Fabricated by Alternating Metal-Assisted Chemical Etching.

PubMed

Chen, Yun; Li, Liyi; Zhang, Cheng; Tuan, Chia-Chi; Chen, Xin; Gao, Jian; Wong, Ching-Ping

2017-02-08

Kinked silicon (Si) nanowires (NWs) have many special properties that make them attractive for a number of applications, such as microfluidics devices, microelectronic devices, and biosensors. However, fabricating NWs with controlled three-dimensional (3D) geometry has been challenging. In this work, a novel method called alternating metal-assisted chemical etching is reported for the fabrication of kinked Si NWs with controlled 3D geometry. By the use of multiple etchants with carefully selected composition, one can control the number of kinks, their locations, and their angles by controlling the number of etchant alternations and the time in each etchant. The resulting number of kinks equals the number times the etchant is alternated, the length of each segment separated by kinks has a linear relationship with the etching time, and the kinking angle is related to the surface tension and viscosity of the etchants. This facile method may provide a feasible and economical way to fabricate novel silicon nanowires, nanostructures, and devices for broad applications.

Nanowire failure: long = brittle and short = ductile.

PubMed

Wu, Zhaoxuan; Zhang, Yong-Wei; Jhon, Mark H; Gao, Huajian; Srolovitz, David J

2012-02-08

Experimental studies of the tensile behavior of metallic nanowires show a wide range of failure modes, ranging from ductile necking to brittle/localized shear failure-often in the same diameter wires. We performed large-scale molecular dynamics simulations of copper nanowires with a range of nanowire lengths and provide unequivocal evidence for a transition in nanowire failure mode with change in nanowire length. Short nanowires fail via a ductile mode with serrated stress-strain curves, while long wires exhibit extreme shear localization and abrupt failure. We developed a simple model for predicting the critical nanowire length for this failure mode transition and showed that it is in excellent agreement with both the simulation results and the extant experimental data. The present results provide a new paradigm for the design of nanoscale mechanical systems that demarcates graceful and catastrophic failure. © 2012 American Chemical Society

CMOS Electrochemical Instrumentation for Biosensor Microsystems: A Review.

PubMed

Li, Haitao; Liu, Xiaowen; Li, Lin; Mu, Xiaoyi; Genov, Roman; Mason, Andrew J

2016-12-31

Modern biosensors play a critical role in healthcare and have a quickly growing commercial market. Compared to traditional optical-based sensing, electrochemical biosensors are attractive due to superior performance in response time, cost, complexity and potential for miniaturization. To address the shortcomings of traditional benchtop electrochemical instruments, in recent years, many complementary metal oxide semiconductor (CMOS) instrumentation circuits have been reported for electrochemical biosensors. This paper provides a review and analysis of CMOS electrochemical instrumentation circuits. First, important concepts in electrochemical sensing are presented from an instrumentation point of view. Then, electrochemical instrumentation circuits are organized into functional classes, and reported CMOS circuits are reviewed and analyzed to illuminate design options and performance tradeoffs. Finally, recent trends and challenges toward on-CMOS sensor integration that could enable highly miniaturized electrochemical biosensor microsystems are discussed. The information in the paper can guide next generation electrochemical sensor design.

CMOS Electrochemical Instrumentation for Biosensor Microsystems: A Review

PubMed Central

Li, Haitao; Liu, Xiaowen; Li, Lin; Mu, Xiaoyi; Genov, Roman; Mason, Andrew J.

2016-01-01

Modern biosensors play a critical role in healthcare and have a quickly growing commercial market. Compared to traditional optical-based sensing, electrochemical biosensors are attractive due to superior performance in response time, cost, complexity and potential for miniaturization. To address the shortcomings of traditional benchtop electrochemical instruments, in recent years, many complementary metal oxide semiconductor (CMOS) instrumentation circuits have been reported for electrochemical biosensors. This paper provides a review and analysis of CMOS electrochemical instrumentation circuits. First, important concepts in electrochemical sensing are presented from an instrumentation point of view. Then, electrochemical instrumentation circuits are organized into functional classes, and reported CMOS circuits are reviewed and analyzed to illuminate design options and performance tradeoffs. Finally, recent trends and challenges toward on-CMOS sensor integration that could enable highly miniaturized electrochemical biosensor microsystems are discussed. The information in the paper can guide next generation electrochemical sensor design. PMID:28042860

Engineering prokaryotic transcriptional activators as metabolite biosensors in yeast.

PubMed

Skjoedt, Mette L; Snoek, Tim; Kildegaard, Kanchana R; Arsovska, Dushica; Eichenberger, Michael; Goedecke, Tobias J; Rajkumar, Arun S; Zhang, Jie; Kristensen, Mette; Lehka, Beata J; Siedler, Solvej; Borodina, Irina; Jensen, Michael K; Keasling, Jay D

2016-11-01

Whole-cell biocatalysts have proven a tractable path toward sustainable production of bulk and fine chemicals. Yet the screening of libraries of cellular designs to identify best-performing biocatalysts is most often a low-throughput endeavor. For this reason, the development of biosensors enabling real-time monitoring of production has attracted attention. Here we applied systematic engineering of multiple parameters to search for a general biosensor design in the budding yeast Saccharomyces cerevisiae based on small-molecule binding transcriptional activators from the prokaryote superfamily of LysR-type transcriptional regulators (LTTRs). We identified a design supporting LTTR-dependent activation of reporter gene expression in the presence of cognate small-molecule inducers. As proof of principle, we applied the biosensors for in vivo screening of cells producing naringenin or cis,cis-muconic acid at different levels, and found that reporter gene output correlated with production. The transplantation of prokaryotic transcriptional activators into the eukaryotic chassis illustrates the potential of a hitherto untapped biosensor resource useful for biotechnological applications.

Biosensor-based microRNA detection: techniques, design, performance, and challenges.

PubMed

Johnson, Blake N; Mutharasan, Raj

2014-04-07

The current state of biosensor-based techniques for amplification-free microRNA (miRNA) detection is critically reviewed. Comparison with non-sensor and amplification-based molecular techniques (MTs), such as polymerase-based methods, is made in terms of transduction mechanism, associated protocol, and sensitivity. Challenges associated with miRNA hybridization thermodynamics which affect assay selectivity and amplification bias are briefly discussed. Electrochemical, electromechanical, and optical classes of miRNA biosensors are reviewed in terms of transduction mechanism, limit of detection (LOD), time-to-results (TTR), multiplexing potential, and measurement robustness. Current trends suggest that biosensor-based techniques (BTs) for miRNA assay will complement MTs due to the advantages of amplification-free detection, LOD being femtomolar (fM)-attomolar (aM), short TTR, multiplexing capability, and minimal sample preparation requirement. Areas of future importance in miRNA BT development are presented which include focus on achieving high measurement confidence and multiplexing capabilities.

Fluidics cube for biosensor miniaturization

NASA Technical Reports Server (NTRS)

Dodson, J. M.; Feldstein, M. J.; Leatzow, D. M.; Flack, L. K.; Golden, J. P.; Ligler, F. S.

2001-01-01

To create a small, portable, fully automated biosensor, a compact means of fluid handling is required. We designed, manufactured, and tested a "fluidics cube" for such a purpose. This cube, made of thermoplastic, contains reservoirs and channels for liquid samples and reagents and operates without the use of any internal valves or meters; it is a passive fluid circuit that relies on pressure relief vents to control fluid movement. We demonstrate the ability of pressure relief vents to control fluid movement and show how to simply manufacture or modify the cube. Combined with the planar array biosensor developed at the Naval Research Laboratory, it brings us one step closer to realizing our goal of a handheld biosensor capable of analyzing multiple samples for multiple analytes.

III-Nitride Nanowire Lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wright, Jeremy Benjamin

2014-07-01

In recent years there has been a tremendous interest in nanoscale optoelectronic devices. Among these devices are semiconductor nanowires whose diameters range from 10-100 nm. To date, nanowires have been grown using many semiconducting material systems and have been utilized as light emitting diodes, photodetectors, and solar cells. Nanowires possess a relatively large index contrast relative to their dielectric environment and can be used as lasers. A key gure of merit that allows for nanowire lasing is the relatively high optical con nement factor. In this work, I discuss the optical characterization of 3 types of III-nitride nanowire laser devices.more » Two devices were designed to reduce the number of lasing modes to achieve singlemode operation. The third device implements low-group velocity mode lasing with a photonic crystal constructed of an array of nanowires. Single-mode operation is necessary in any application where high beam quality and single frequency operation is required. III-Nitride nanowire lasers typically operate in a combined multi-longitudinal and multi-transverse mode state. Two schemes are introduced here for controlling the optical modes and achieving single-mode op eration. The rst method involves reducing the diameter of individual nanowires to the cut-o condition, where only one optical mode propagates in the wire. The second method employs distributed feedback (DFB) to achieve single-mode lasing by placing individual GaN nanowires onto substrates with etched gratings. The nanowire-grating substrate acted as a distributed feedback mirror producing single mode operation at 370 nm with a mode suppression ratio (MSR) of 17 dB. The usage of lasers for solid state lighting has the potential to further reduce U.S. lighting energy usage through an increase in emitter e ciency. Advances in nanowire fabrication, speci cally a two-step top-down approach, have allowed for the demonstration of a multi-color array of lasers on a single chip that

Large Scale Bacterial Colony Screening of Diversified FRET Biosensors

PubMed Central

Litzlbauer, Julia; Schifferer, Martina; Ng, David; Fabritius, Arne; Thestrup, Thomas; Griesbeck, Oliver

2015-01-01

Biosensors based on Förster Resonance Energy Transfer (FRET) between fluorescent protein mutants have started to revolutionize physiology and biochemistry. However, many types of FRET biosensors show relatively small FRET changes, making measurements with these probes challenging when used under sub-optimal experimental conditions. Thus, a major effort in the field currently lies in designing new optimization strategies for these types of sensors. Here we describe procedures for optimizing FRET changes by large scale screening of mutant biosensor libraries in bacterial colonies. We describe optimization of biosensor expression, permeabilization of bacteria, software tools for analysis, and screening conditions. The procedures reported here may help in improving FRET changes in multiple suitable classes of biosensors. PMID:26061878

Enhanced photovoltaic performance of an inclined nanowire array solar cell.

PubMed

Wu, Yao; Yan, Xin; Zhang, Xia; Ren, Xiaomin

2015-11-30

An innovative solar cell based on inclined p-i-n nanowire array is designed and analyzed. The results show that the inclined geometry can sufficiently increase the conversion efficiency of solar cells by enhancing the absorption of light in the active region. By tuning the nanowire array density, nanowire diameter, nanowire length, as well as the proportion of intrinsic region of the inclined nanowire solar cell, a remarkable efficiency in excess of 16% can be obtained in GaAs. Similar results have been obtained in InP and Si nanowire solar cells, demonstrating the universality of the performance enhancement of inclined nanowire arrays.

Superenhancers: novel opportunities for nanowire optoelectronics.

PubMed

Khudiyev, Tural; Bayindir, Mehmet

2014-12-16

Nanowires play a crucial role in the development of new generation optoelectronic devices ranging from photovoltaics to photodetectors, as these designs capitalize on the low material usage, utilize leaky-mode optical resonances and possess high conversion efficiencies associated with nanowire geometry. However, their current schemes lack sufficient absorption capacity demanded for their practical applicability, and more efficient materials cannot find widespread usage in these designs due to their rarity and cost. Here we suggest a novel and versatile nanoconcentrator scheme utilizing unique optical features of non-resonant Mie (NRM) scattering regime associated with low-index structures. The scattering regime is highly compatible with resonant Mie absorption effect taking place in nanowire absorbers. This technique in its optimized forms can provide up to 1500% total absorption enhancement, 400-fold material save and is suitable for large-area applications with significant area preservation compared to thin-film of same materials. Proposed superenhancer concept with its exceptional features such as broadband absorption enhancement, polarization immunity and material-independent manner paves the way for development of efficient nanowire photosensors or solar thermophotovoltaic devices and presents novel design opportunities for self-powered nanosystems.

Bandgap engineering of GaN nanowires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ming, Bang-Ming; Yan, Hui; Wang, Ru-Zhi, E-mail: wrz@bjut.edu.cn, E-mail: yamcy@csrc.ac.cn

2016-05-15

Bandgap engineering has been a powerful technique for manipulating the electronic and optical properties of semiconductors. In this work, a systematic investigation of the electronic properties of [0001] GaN nanowires was carried out using the density functional based tight-binding method (DFTB). We studied the effects of geometric structure and uniaxial strain on the electronic properties of GaN nanowires with diameters ranging from 0.8 to 10 nm. Our results show that the band gap of GaN nanowires depends linearly on both the surface to volume ratio (S/V) and tensile strain. The band gap of GaN nanowires increases linearly with S/V, whilemore » it decreases linearly with increasing tensile strain. These linear relationships provide an effect way in designing GaN nanowires for their applications in novel nano-devices.« less

Ni-DNA-based nanowires and nanodevices

NASA Astrophysics Data System (ADS)

Chang, Chia-Ching; Yuan, Chiun-Jye; Jian, Wen-Bin; Chen, Yu-Chang; di Ventra, Massimiliano

DNA is a highly versatile biopolymer that has been a recent focus in the field of nanomachines and nanoelectronics. DNA exhibits high stability, adjustable conductance, self-organizing capability, programmability and vast information storage. It is an ideal material in the applications of nanodevices, nanoelectronics, and molecular computing. Low conductance of native DNA renders applications difficult. However, doping with nickel ions tunes the DNA into a conducting polymer. Further studies showed that nickel ions containing DNA (Ni-DNA) nanowires exhibit characteristics of memristor and memcapacitor making them a potential mass information storage system. In summary, Ni-DNA has promising applications in a variety of fields, including nanoelectronics, biosensors and memcomputing. This study was supported in part by the Ministry of Science and Technology (MOST), Taiwan (ROC) MOST 103-2112-M-009-011 -MY3, and MOST 105-2627-M-009-006.

Ultra-thin bimetallic alloy nanowires with porous architecture/monolayer MoS2 nanosheet as a highly sensitive platform for the electrochemical assay of hazardous omethoate pollutant.

PubMed

Song, Dandan; Li, Qian; Lu, Xiong; Li, Yanshan; Li, Yan; Wang, Yuanzhe; Gao, Faming

2018-06-18

A novel electrochemical biosensor was designed for sensitive detection of organophosphate pesticides based on three-dimensional porous bimetallic alloy architecture with ultrathin nanowires (PdCo NWs, PdCu NWs, PdNi NWs) and monolayer MoS 2 nanosheet (m-MoS 2 ). The bimetallic alloy NWs/m-MoS 2 nanomaterials were used as a sensing platform for electrochemical analysis of omethoate, a representative organophosphate pesticide, via acetylcholinesterase inhibition pathway. We demonstrated that all three bimetallic alloy NWs enhanced electrochemical responses of enzymatic biosensor, benefited from bimetallic synergistic action and porous structure. In particular, PdNi NWs outperformed other two bimetallic alloy. Moreover, PdNi NWs/m-MoS 2 as an electronic transducer is superior to the corresponding biosensor in the absence of monolayer MoS 2 nanosheet, which arise from synergistic signal amplification effect between different components. Under optimized conditions, the developed biosensor on the basis of PdNi NWs/m-MoS 2 shows outstanding performance for the electrochemical assay of omethoate, such as a wide linear range (10 -13 M∼10 -7 M), a low detection limit of 0.05 pM at a signal-to-noise ratio of 3, high sensitivity and long-time stability. The results demonstrate that bimetallic alloy NWs/m-MoS 2 nanocomposites could be excellent transducers to promote electron transfer for the electrochemical reactions, holding great potentials in the construction of current and future biosensing devices. Copyright © 2018 Elsevier B.V. All rights reserved.

Biosensors and bioelectronics on smartphone for portable biochemical detection.

PubMed

Zhang, Diming; Liu, Qingjun

2016-01-15

Smartphone has been widely integrated with sensors, such as test strips, sensor chips, and hand-held detectors, for biochemical detections due to its portability and ubiquitous availability. Utilizing built-in function modules, smartphone is often employed as controller, analyzer, and displayer for rapid, real-time, and point-of-care monitoring, which can significantly simplify design and reduce cost of the detecting systems. This paper presents a review of biosensors and bioelectronics on smartphone for portable biochemical detections. The biosensors and bioelectronics based on smartphone can mainly be classified into biosensors using optics, surface plasmon resonance, electrochemistry, and near-field communication. The developments of these biosensors and bioelectronics on smartphone are reviewed along with typical biochemical detecting cases. Sensor strategies, detector attachments, and coupling methods are highlighted to show designs of the compact, lightweight, and low-cost sensor systems. The performances and advantages of these designs are introduced with their applications in healthcare diagnosis, environment monitoring, and food evaluation. With advances in micro-manufacture, sensor technology, and miniaturized electronics, biosensor and bioelectronic devices on smartphone can be used to perform biochemical detections as common and convenient as electronic tag readout in foreseeable future. Copyright © 2015 Elsevier B.V. All rights reserved.

Photonic crystal-based optical biosensor: a brief investigation

NASA Astrophysics Data System (ADS)

Divya, J.; Selvendran, S.; Sivanantha Raja, A.

2018-06-01

In this paper, a two-dimensional photonic crystal biosensor for medical applications based on two waveguides and a nanocavity was explored with different shoulder-coupled nanocavity structures. The most important biosensor parameters, like the sensitivity and quality factor, can be significantly improved. By injecting an analyte into a sensing hole, the refractive index of the hole was changed. This refractive index biosensor senses the changes and shifts its operating wavelength accordingly. The transmission characteristics of light in the biosensor under different refractive indices that correspond to the change in the analyte concentration are analyzed by the finite-difference time-domain method. The band gap for each structure is designed and observed by the plane wave expansion method. These proposed structures are designed to obtain an analyte refractive index variation of about 1–1.5 in an optical wavelength range of 1.250–1.640 µm. Accordingly, an improved sensitivity of 136.6 nm RIU‑1 and a quality factor as high as 3915 is achieved. An important feature of this structure is its very small dimensions. Such a combination of attributes makes the designed structure a promising element for label-free biosensing applications.

Nanowires Bending over Backward from Strain Partitioning in Asymmetric Core-Shell Heterostructures.

PubMed

Lewis, Ryan B; Corfdir, Pierre; Küpers, Hanno; Flissikowski, Timur; Brandt, Oliver; Geelhaar, Lutz

2018-04-11

The flexibility and quasi-one-dimensional nature of nanowires offer wide-ranging possibilities for novel heterostructure design and strain engineering. In this work, we realize arrays of extremely and controllably bent nanowires comprising lattice-mismatched and highly asymmetric core-shell heterostructures. Strain sharing across the nanowire heterostructures is sufficient to bend vertical nanowires over backward to contact either neighboring nanowires or the substrate itself, presenting new possibilities for designing nanowire networks and interconnects. Photoluminescence spectroscopy on bent-nanowire heterostructures reveals that spatially varying strain fields induce charge carrier drift toward the tensile-strained outside of the nanowires, and that the polarization response of absorbed and emitted light is controlled by the bending direction. This unconventional strain field is employed for light emission by placing an active region of quantum dots at the outer side of a bent nanowire to exploit the carrier drift and tensile strain. These results demonstrate how bending in nanoheterostructures opens up new degrees of freedom for strain and device engineering.

Recent advances in polyaniline based biosensors.

PubMed

Dhand, Chetna; Das, Maumita; Datta, Monika; Malhotra, B D

2011-02-15

The present paper contains a detailed overview of recent advances relating to polyaniline (PANI) as a transducer material for biosensor applications. This conducting polymer provides enormous opportunities for binding biomolecules, tuning their bio-catalytic properties, rapid electron transfer and direct communication to produce a range of analytical signals and new analytical applications. Merging the specific nature of different biomolecules (enzymes, nucleic acids, antibodies, etc.) and the key properties of this modern conducting matrix, possible biosensor designs and their biosensing characteristics have been discussed. Efforts have been made to discuss and explore various characteristics of PANI responsible for direct electron transfer leading towards fabrication of mediator-less biosensors. Copyright © 2010 Elsevier B.V. All rights reserved.

Graphene-Based Optical Biosensors and Imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, Zhiwen; He, Shijiang; Pei, Hao

2014-01-13

This chapter focuses on the design, fabrication and application of graphene based optical nanobiosensors. The emerging graphene based optical nanobiosensors demonstrated the promising bioassay and biomedical applications thanking to the unique optical features of graphene. According to the different applications, the graphene can be tailored to form either fluorescent emitter or efficient fluorescence quencher. The exceptional electronic feature of graphene makes it a powerful platform for fabricating the SPR and SERS biosensors. Today the graphene based optical biosensors have been constructed to detect various targets including ions, small biomolecules, DNA/RNA and proteins. This chapter reviews the recent progress in graphene-basedmore » optical biosensors and discusses the opportunities and challenges in this field.« less

Pulsed excitation system to measure the resonant frequency of magnetoelastic biosensors

NASA Astrophysics Data System (ADS)

Xie, Hong; Chai, Yating; Horikawa, Shin; Wikle, Howard C.; Chin, Bryan A.

2014-05-01

An electrical circuit was designed and tested to measure the resonant frequency of micron-scale magnetoelastic (ME) biosensors using a pulsed wave excitation technique. In this circuit, a square pulse current is applied to an excitation coil to excite the vibration of ME biosensors and a pick-up coil is used to sense the ME biosensor's mechanical vibration and convert it to an electrical output signal. The output signal is filtered and amplified by a custom designed circuit to allow the measurement of the resonant frequency of the ME biosensor from which the detection of specific pathogens can be made. As a proof-in-concept experiment, JRB7 phage-coated ME biosensors were used to detect different concentrations of Bacillus anthracis Sterne strain spores. A statistically significant difference was observed for concentrations of 5 × 102 spore/ml and above.

Biosensors.

ERIC Educational Resources Information Center

Rechnitz, Garry A.

1988-01-01

Describes theory and principles behind biosensors that incorporate biological components as part of a sensor or probe. Projects major applications in medicine and veterinary medicine, biotechnology, food and agriculture, environmental studies, and the military. Surveys current use of biosensors. (ML)

Biosensor Architectures for High-Fidelity Reporting of Cellular Signaling

PubMed Central

Dushek, Omer; Lellouch, Annemarie C.; Vaux, David J.; Shahrezaei, Vahid

2014-01-01

Understanding mechanisms of information processing in cellular signaling networks requires quantitative measurements of protein activities in living cells. Biosensors are molecular probes that have been developed to directly track the activity of specific signaling proteins and their use is revolutionizing our understanding of signal transduction. The use of biosensors relies on the assumption that their activity is linearly proportional to the activity of the signaling protein they have been engineered to track. We use mechanistic mathematical models of common biosensor architectures (single-chain FRET-based biosensors), which include both intramolecular and intermolecular reactions, to study the validity of the linearity assumption. As a result of the classic mechanism of zero-order ultrasensitivity, we find that biosensor activity can be highly nonlinear so that small changes in signaling protein activity can give rise to large changes in biosensor activity and vice versa. This nonlinearity is abolished in architectures that favor the formation of biosensor oligomers, but oligomeric biosensors produce complicated FRET states. Based on this finding, we show that high-fidelity reporting is possible when a single-chain intermolecular biosensor is used that cannot undergo intramolecular reactions and is restricted to forming dimers. We provide phase diagrams that compare various trade-offs, including observer effects, which further highlight the utility of biosensor architectures that favor intermolecular over intramolecular binding. We discuss challenges in calibrating and constructing biosensors and highlight the utility of mathematical models in designing novel probes for cellular signaling. PMID:25099816

Silicon nanowire field-effect transistors for the detection of proteins

NASA Astrophysics Data System (ADS)

Madler, Carsten

to implantable biosensors wirelessly, eliminating the need for batteries. A metamaterial split ring resonator is integrated with a rectifying circuit for efficient conversion of microwave radiation to direct electrical power. We studied the near-field behavior of this rectenna with respect to distance, polarization, power, and frequency. Using a 100 mW microwave power source, we demonstrated operating a simple silicon nanowire pH sensor with light indicator.

Cleaved-coupled nanowire lasers

PubMed Central

Gao, Hanwei; Fu, Anthony; Andrews, Sean C.; Yang, Peidong

2013-01-01

The miniaturization of optoelectronic devices is essential for the continued success of photonic technologies. Nanowires have been identified as potential building blocks that mimic conventional photonic components such as interconnects, waveguides, and optical cavities at the nanoscale. Semiconductor nanowires with high optical gain offer promising solutions for lasers with small footprints and low power consumption. Although much effort has been directed toward controlling their size, shape, and composition, most nanowire lasers currently suffer from emitting at multiple frequencies simultaneously, arising from the longitudinal modes native to simple Fabry–Pérot cavities. Cleaved-coupled cavities, two Fabry–Pérot cavities that are axially coupled through an air gap, are a promising architecture to produce single-frequency emission. The miniaturization of this concept, however, imposes a restriction on the dimensions of the intercavity gaps because severe optical losses are incurred when the cross-sectional dimensions of cavities become comparable to the lasing wavelength. Here we theoretically investigate and experimentally demonstrate spectral manipulation of lasing modes by creating cleaved-coupled cavities in gallium nitride (GaN) nanowires. Lasing operation at a single UV wavelength at room temperature was achieved using nanoscale gaps to create the smallest cleaved-coupled cavities to date. Besides the reduced number of lasing modes, the cleaved-coupled nanowires also operate with a lower threshold gain than that of the individual component nanowires. Good agreement was found between the measured lasing spectra and the predicted spectral modes obtained by simulating optical coupling properties. This agreement between theory and experiment presents design principles to rationally control the lasing modes in cleaved-coupled nanowire lasers. PMID:23284173

Protease biosensors based on peptide-nanocellulose conjugates: from molecular design to dressing interface

USDA-ARS?s Scientific Manuscript database

The development of point of care diagnostic protease sensors applied to wound healing has received increased interest for chronic wound treatment and as an interface with chronic wound dressings. Biosensor technology has grown exponentially in recent years. Here we focus on nanocelluosic biosensor t...

A CMOS wireless biomolecular sensing system-on-chip based on polysilicon nanowire technology.

PubMed

Huang, C-W; Huang, Y-J; Yen, P-W; Tsai, H-H; Liao, H-H; Juang, Y-Z; Lu, S-S; Lin, C-T

2013-11-21

As developments of modern societies, an on-field and personalized diagnosis has become important for disease prevention and proper treatment. To address this need, in this work, a polysilicon nanowire (poly-Si NW) based biosensor system-on-chip (bio-SSoC) is designed and fabricated by a 0.35 μm 2-Poly-4-Metal (2P4M) complementary metal-oxide-semiconductor (CMOS) process provided by a commercialized semiconductor foundry. Because of the advantages of CMOS system-on-chip (SoC) technologies, the poly-Si NW biosensor is integrated with a chopper differential-difference amplifier (DDA) based analog-front-end (AFE), a successive approximation analog-to-digital converter (SAR ADC), and a microcontroller to have better sensing capabilities than a traditional Si NW discrete measuring system. In addition, an on-off key (OOK) wireless transceiver is also integrated to form a wireless bio-SSoC technology. This is pioneering work to harness the momentum of CMOS integrated technology into emerging bio-diagnosis technologies. This integrated technology is experimentally examined to have a label-free and low-concentration biomolecular detection for both Hepatitis B Virus DNA (10 fM) and cardiac troponin I protein (3.2 pM). Based on this work, the implemented wireless bio-SSoC has demonstrated a good biomolecular sensing characteristic and a potential for low-cost and mobile applications. As a consequence, this developed technology can be a promising candidate for on-field and personalized applications in biomedical diagnosis.

Biosensor technology: technology push versus market pull.

PubMed

Luong, John H T; Male, Keith B; Glennon, Jeremy D

2008-01-01

Biosensor technology is based on a specific biological recognition element in combination with a transducer for signal processing. Since its inception, biosensors have been expected to play a significant analytical role in medicine, agriculture, food safety, homeland security, environmental and industrial monitoring. However, the commercialization of biosensor technology has significantly lagged behind the research output as reflected by a plethora of publications and patenting activities. The rationale behind the slow and limited technology transfer could be attributed to cost considerations and some key technical barriers. Analytical chemistry has changed considerably, driven by automation, miniaturization, and system integration with high throughput for multiple tasks. Such requirements pose a great challenge in biosensor technology which is often designed to detect one single or a few target analytes. Successful biosensors must be versatile to support interchangeable biorecognition elements, and in addition miniaturization must be feasible to allow automation for parallel sensing with ease of operation at a competitive cost. A significant upfront investment in research and development is a prerequisite in the commercialization of biosensors. The progress in such endeavors is incremental with limited success, thus, the market entry for a new venture is very difficult unless a niche product can be developed with a considerable market volume.

Detection beyond the Debye screening length in a high-frequency nanoelectronic biosensor.

PubMed

Kulkarni, Girish S; Zhong, Zhaohui

2012-02-08

Nanosensors based on the unique electronic properties of nanotubes and nanowires offer high sensitivity and have the potential to revolutionize the field of Point-of-Care (POC) medical diagnosis. The direct current (dc) detection of a wide array of organic and inorganic molecules has been demonstrated on these devices. However, sensing mechanism based on measuring changes in dc conductance fails at high background salt concentrations, where the sensitivity of the devices suffers from the ionic screening due to mobile ions present in the solution. Here, we successfully demonstrate that the fundamental ionic screening effect can be mitigated by operating single-walled carbon nanotube field effect transistor as a high-frequency biosensor. The nonlinear mixing between the alternating current excitation field and the molecular dipole field can generate mixing current sensitive to the surface-bound biomolecules. Electrical detection of monolayer streptavidin binding to biotin in 100 mM buffer solution is achieved at a frequency beyond 1 MHz. Theoretical modeling confirms improved sensitivity at high frequency through mitigation of the ionic screening effect. The results should promise a new biosensing platform for POC detection, where biosensors functioning directly in physiologically relevant condition are desired. © 2012 American Chemical Society

Biosensors for Cell Analysis.

PubMed

Zhou, Qing; Son, Kyungjin; Liu, Ying; Revzin, Alexander

2015-01-01

Biosensors first appeared several decades ago to address the need for monitoring physiological parameters such as oxygen or glucose in biological fluids such as blood. More recently, a new wave of biosensors has emerged in order to provide more nuanced and granular information about the composition and function of living cells. Such biosensors exist at the confluence of technology and medicine and often strive to connect cell phenotype or function to physiological or pathophysiological processes. Our review aims to describe some of the key technological aspects of biosensors being developed for cell analysis. The technological aspects covered in our review include biorecognition elements used for biosensor construction, methods for integrating cells with biosensors, approaches to single-cell analysis, and the use of nanostructured biosensors for cell analysis. Our hope is that the spectrum of possibilities for cell analysis described in this review may pique the interest of biomedical scientists and engineers and may spur new collaborations in the area of using biosensors for cell analysis.

Size-dependent fracture behavior of silver nanowires.

PubMed

Cao, Ke; Han, Ying; Zhang, Hongti; Gao, Libo; Yang, Hongwei; Chen, Jialin; Li, Yuxiu; Lu, Yang

2018-07-20

Silver (Ag) nanowires have great potential to be used in the flexible electronics industry for their applications in flexible, transparent conductors due to high conductivity and light reflectivity. Those applications always involve mechanical loading and deformations, which requires an in-depth understanding of their mechanical behavior and performance under loadings. However, current understanding on the mechanical properties of Ag nanowires is limited, especially on their size-dependent fracture behavior. In this work, mechanical properties of Ag nanowires with diameters ranging from 50 to 300 nm were systematically studied by in situ TEM tensile testing for the first time. The size effect was clearly found, with the increasing of the diameter of Ag nanowires, the ultimate tensile stress decreased. More importantly, the fracture behavior of Ag nanowire was studied and a brittle-to-ductile transition in fracture behavior was observed at the diameters around 100 nm which could be attributed to the dislocation activities within the geometry confinement. This work could give insights for understanding nanosized Ag wires and the design of Ag nanowire-based flexible devices and touchable panels.

Size-dependent fracture behavior of silver nanowires

NASA Astrophysics Data System (ADS)

Cao, Ke; Han, Ying; Zhang, Hongti; Gao, Libo; Yang, Hongwei; Chen, Jialin; Li, Yuxiu; Lu, Yang

2018-07-01

Silver (Ag) nanowires have great potential to be used in the flexible electronics industry for their applications in flexible, transparent conductors due to high conductivity and light reflectivity. Those applications always involve mechanical loading and deformations, which requires an in-depth understanding of their mechanical behavior and performance under loadings. However, current understanding on the mechanical properties of Ag nanowires is limited, especially on their size-dependent fracture behavior. In this work, mechanical properties of Ag nanowires with diameters ranging from 50 to 300 nm were systematically studied by in situ TEM tensile testing for the first time. The size effect was clearly found, with the increasing of the diameter of Ag nanowires, the ultimate tensile stress decreased. More importantly, the fracture behavior of Ag nanowire was studied and a brittle-to-ductile transition in fracture behavior was observed at the diameters around 100 nm which could be attributed to the dislocation activities within the geometry confinement. This work could give insights for understanding nanosized Ag wires and the design of Ag nanowire-based flexible devices and touchable panels.

Nanowire-based detector

DOEpatents

Berggren, Karl K; Hu, Xiaolong; Masciarelli, Daniele

2014-06-24

Systems, articles, and methods are provided related to nanowire-based detectors, which can be used for light detection in, for example, single-photon detectors. In one aspect, a variety of detectors are provided, for example one including an electrically superconductive nanowire or nanowires constructed and arranged to interact with photons to produce a detectable signal. In another aspect, fabrication methods are provided, including techniques to precisely reproduce patterns in subsequently formed layers of material using a relatively small number of fabrication steps. By precisely reproducing patterns in multiple material layers, one can form electrically insulating materials and electrically conductive materials in shapes such that incoming photons are redirected toward a nearby electrically superconductive materials (e.g., electrically superconductive nanowire(s)). For example, one or more resonance structures (e.g., comprising an electrically insulating material), which can trap electromagnetic radiation within its boundaries, can be positioned proximate the nanowire(s). The resonance structure can include, at its boundaries, electrically conductive material positioned proximate the electrically superconductive nanowire such that light that would otherwise be transmitted through the sensor is redirected toward the nanowire(s) and detected. In addition, electrically conductive material can be positioned proximate the electrically superconductive nanowire (e.g. at the aperture of the resonant structure), such that light is directed by scattering from this structure into the nanowire.

Automated characterization and assembly of individual nanowires for device fabrication.

PubMed

Yu, Kaiyan; Yi, Jingang; Shan, Jerry W

2018-05-15

The automated sorting and positioning of nanowires and nanotubes is essential to enabling the scalable manufacturing of nanodevices for a variety of applications. However, two fundamental challenges still remain: (i) automated placement of individual nanostructures in precise locations, and (ii) the characterization and sorting of highly variable nanomaterials to construct well-controlled nanodevices. Here, we propose and demonstrate an integrated, electric-field based method for the simultaneous automated characterization, manipulation, and assembly of nanowires (ACMAN) with selectable electrical conductivities into nanodevices. We combine contactless and solution-based electro-orientation spectroscopy and electrophoresis-based motion-control, planning and manipulation strategies to simultaneously characterize and manipulate multiple individual nanowires. These nanowires can be selected according to their electrical characteristics and precisely positioned at different locations in a low-conductivity liquid to form functional nanodevices with desired electrical properties. We validate the ACMAN design by assembling field-effect transistors (FETs) with silicon nanowires of selected electrical conductivities. The design scheme provides a key enabling technology for the scalable, automated sorting and assembly of nanowires and nanotubes to build functional nanodevices.

Dielectrophoretic investigation of Bi₂Te₃ nanowires-a microfabricated thermoelectric characterization platform for measuring the thermoelectric and structural properties of single nanowires.

PubMed

Wang, Zhi; Kojda, Danny; Peranio, Nicola; Kroener, Michael; Mitdank, Rüdiger; Toellner, William; Nielsch, Kornelius; Fischer, Saskia F; Gutsch, Sebastian; Zacharias, Margit; Eibl, Oliver; Woias, Peter

2015-03-27

In this article a microfabricated thermoelectric nanowire characterization platform to investigate the thermoelectric and structural properties of single nanowires is presented. By means of dielectrophoresis (DEP), a method to manipulate and orient nanowires in a controlled way to assemble them onto our measurement platform is introduced. The thermoelectric platform fabricated with optimally designed DEP electrodes results in a yield of nanowire assembly of approximately 90% under an applied peak-to-peak ac signal Vpp = 10 V and frequency f = 20 MHz within a series of 200 experiments. Ohmic contacts between the aligned single nanowire and the electrodes on the platform are established by electron beam-induced deposition. The Seebeck coefficient and electrical conductivity of electrochemically synthesized Bi2Te3 nanowires are measured to be -51 μV K(-1) and (943 ± 160)/(Ω(-1) cm(-1)), respectively. Chemical composition and crystallographic structure are obtained using transmission electron microscopy. The selected nanowire is observed to be single crystalline over its entire length and no grain boundaries are detected. At the surface of the nanowire, 66.1 ± 1.1 at.% Te and 34.9 ± 1.1 at.% Bi are observed. In contrast, chemical composition of 64.2 at.% Te and 35.8 at.% Bi is detected in the thick center of the nanowire.

Composite nanowire networks for biological sensor platforms

NASA Astrophysics Data System (ADS)

Jabal, Jamie Marie Francisco

The main goal of this research is to design, fabricate, and test a nanomaterial-based platform adequate for the measurement of physiological changes in living cells. The two primary objectives toward this end are (1) the synthesis and selection of a suitable nanomaterial and (2) the demonstration of cellular response to a direct stimulus. Determining a useful nanomaterial morphology and behavior within a sensor configuration presented challenges based on cellular integration and access to electrochemical characterization. The prospect for feasible optimization and eventual scale-up in technology were also significant. Constraining criteria are that the nanomaterial detector must (a) be cheap and relatively easy to fabricate controllably, (b) encourage cell attachment, (c) exhibit consistent wettability over time, and (d) facilitate electrochemical processes. The ultimate goal would be to transfer a proof-of-principle and proof-of-design for a whole-cell sensor technology that is cost effective and has a potential for hand-held packaging. Initial tasks were to determine an effective and highly-functional nanomaterial for biosensors by assessing wettability, morphology and conductivity behavior of several candidate materials: gallium nitride nanowires, silicon dioxide nanosprings and nanowires, and titania nanofibers. Electrospinning poly(vinyl pyrrolidone)-coated titania nano- and microfibers (O20 nm--2 microm) into a pseudo-random network is controllable to a uniformity of 1--2° in contact angle. The final electrode can be prepared with a precise wettability ranging from partial wetting to ultrahydrophobic (170°) on a variety of substrates: glass, indium tin oxide, silicon, and aluminum. Fiber mats exhibit excellent mechanical stability against rinsing, and support the incubation of epithelial (skin) and pancreatic cells. Impedance spectroscopy on the whole-cell sensor shows resistive changes attributed to cell growth as well as complex frequency

A global benchmark study using affinity-based biosensors

PubMed Central

Rich, Rebecca L.; Papalia, Giuseppe A.; Flynn, Peter J.; Furneisen, Jamie; Quinn, John; Klein, Joshua S.; Katsamba, Phini S.; Waddell, M. Brent; Scott, Michael; Thompson, Joshua; Berlier, Judie; Corry, Schuyler; Baltzinger, Mireille; Zeder-Lutz, Gabrielle; Schoenemann, Andreas; Clabbers, Anca; Wieckowski, Sebastien; Murphy, Mary M.; Page, Phillip; Ryan, Thomas E.; Duffner, Jay; Ganguly, Tanmoy; Corbin, John; Gautam, Satyen; Anderluh, Gregor; Bavdek, Andrej; Reichmann, Dana; Yadav, Satya P.; Hommema, Eric; Pol, Ewa; Drake, Andrew; Klakamp, Scott; Chapman, Trevor; Kernaghan, Dawn; Miller, Ken; Schuman, Jason; Lindquist, Kevin; Herlihy, Kara; Murphy, Michael B.; Bohnsack, Richard; Andrien, Bruce; Brandani, Pietro; Terwey, Danny; Millican, Rohn; Darling, Ryan J.; Wang, Liann; Carter, Quincy; Dotzlaf, Joe; Lopez-Sagaseta, Jacinto; Campbell, Islay; Torreri, Paola; Hoos, Sylviane; England, Patrick; Liu, Yang; Abdiche, Yasmina; Malashock, Daniel; Pinkerton, Alanna; Wong, Melanie; Lafer, Eileen; Hinck, Cynthia; Thompson, Kevin; Primo, Carmelo Di; Joyce, Alison; Brooks, Jonathan; Torta, Federico; Bagge Hagel, Anne Birgitte; Krarup, Janus; Pass, Jesper; Ferreira, Monica; Shikov, Sergei; Mikolajczyk, Malgorzata; Abe, Yuki; Barbato, Gaetano; Giannetti, Anthony M.; Krishnamoorthy, Ganeshram; Beusink, Bianca; Satpaev, Daulet; Tsang, Tiffany; Fang, Eric; Partridge, James; Brohawn, Stephen; Horn, James; Pritsch, Otto; Obal, Gonzalo; Nilapwar, Sanjay; Busby, Ben; Gutierrez-Sanchez, Gerardo; Gupta, Ruchira Das; Canepa, Sylvie; Witte, Krista; Nikolovska-Coleska, Zaneta; Cho, Yun Hee; D’Agata, Roberta; Schlick, Kristian; Calvert, Rosy; Munoz, Eva M.; Hernaiz, Maria Jose; Bravman, Tsafir; Dines, Monica; Yang, Min-Hsiang; Puskas, Agnes; Boni, Erica; Li, Jiejin; Wear, Martin; Grinberg, Asya; Baardsnes, Jason; Dolezal, Olan; Gainey, Melicia; Anderson, Henrik; Peng, Jinlin; Lewis, Mark; Spies, Peter; Trinh, Quyhn; Bibikov, Sergei; Raymond, Jill; Yousef, Mohammed; Chandrasekaran, Vidya; Feng, Yuguo; Emerick, Anne; Mundodo, Suparna; Guimaraes, Rejane; McGirr, Katy; Li, Yue-Ji; Hughes, Heather; Mantz, Hubert; Skrabana, Rostislav; Witmer, Mark; Ballard, Joshua; Martin, Loic; Skladal, Petr; Korza, George; Laird-Offringa, Ite; Lee, Charlene S.; Khadir, Abdelkrim; Podlaski, Frank; Neuner, Phillippe; Rothacker, Julie; Rafique, Ashique; Dankbar, Nico; Kainz, Peter; Gedig, Erk; Vuyisich, Momchilo; Boozer, Christina; Ly, Nguyen; Toews, Mark; Uren, Aykut; Kalyuzhniy, Oleksandr; Lewis, Kenneth; Chomey, Eugene; Pak, Brian J.; Myszka, David G.

2013-01-01

To explore the variability in biosensor studies, 150 participants from 20 countries were given the same protein samples and asked to determine kinetic rate constants for the interaction. We chose a protein system that was amenable to analysis using different biosensor platforms as well as by users of different expertise levels. The two proteins (a 50-kDa Fab and a 60-kDa glutathione S-transferase [GST] antigen) form a relatively high-affinity complex, so participants needed to optimize several experimental parameters, including ligand immobilization and regeneration conditions as well as analyte concentrations and injection/dissociation times. Although most participants collected binding responses that could be fit to yield kinetic parameters, the quality of a few data sets could have been improved by optimizing the assay design. Once these outliers were removed, the average reported affinity across the remaining panel of participants was 620 pM with a standard deviation of 980 pM. These results demonstrate that when this biosensor assay was designed and executed appropriately, the reported rate constants were consistent, and independent of which protein was immobilized and which biosensor was used. PMID:19133223

Surface stress-based biosensors.

PubMed

Sang, Shengbo; Zhao, Yuan; Zhang, Wendong; Li, Pengwei; Hu, Jie; Li, Gang

2014-01-15

Surface stress-based biosensors, as one kind of label-free biosensors, have attracted lots of attention in the process of information gathering and measurement for the biological, chemical and medical application with the development of technology and society. This kind of biosensors offers many advantages such as short response time (less than milliseconds) and a typical sensitivity at nanogram, picoliter, femtojoule and attomolar level. Furthermore, it simplifies sample preparation and testing procedures. In this work, progress made towards the use of surface stress-based biosensors for achieving better performance is critically reviewed, including our recent achievement, the optimally circular membrane-based biosensors and biosensor array. The further scientific and technological challenges in this field are also summarized. Critical remark and future steps towards the ultimate surface stress-based biosensors are addressed. Copyright © 2013 Elsevier B.V. All rights reserved.

Mechanical behavior enhancement of ZnO nanowire by embedding different nanowires

NASA Astrophysics Data System (ADS)

Vazinishayan, Ali; Yang, Shuming; Lambada, Dasaradha Rao; Wang, Yiming

2018-06-01

In this work, we employed commercial finite element modeling (FEM) software package ABAQUS to analyze mechanical properties of ZnO nanowire before and after embedding with different kinds of nanowires, having different materials and cross-section models such as Au (circular), Ag (pentagonal) and Si (rectangular) using three point bending technique. The length and diameter of the ZnO nanowire were measured to be 12,280 nm and 103.2 nm, respectively. In addition, Au, Ag and Si nanowires were considered to have the length of 12,280 nm and the diameter of 27 nm. It was found that after embedding Si nanowire with rectangular cross-section into the ZnO nanowire, the distribution of Von Misses stresses criterion, displacement and strain were decreased than the other nanowires embedded. The highest stiffness, the elastic deformation and the high strength against brittle failure have been made by Si nanowire comparison to the Au and Ag nanowires, respectively.

High S/N ratio slotted step piezoresistive microcantilever designs for biosensors.

PubMed

Ansari, Mohd Zahid; Cho, Chongdu

2013-03-26

This study proposes new microcantilever designs in slotted step configuration to improve the S/N ratio of surface stress-based sensors used in physical, chemical, biochemical and biosensor applications. The cantilevers are made of silicon dioxide with a u-shaped silicon piezoresistor in p-doped. The cantilever step length and piezoresistor length is varied along with the operating voltage to characterise the surface stress sensitivity and thermal drifting sensitivity of the cantilevers when used as immunosensor. The numerical analysis is performed using ANSYS Multiphysics. Results show the surface stress sensitivity and the S/N ratio of the slotted step cantilevers is improved by more than 32% and 22%, respectively, over its monolithic counterparts.

High S/N Ratio Slotted Step Piezoresistive Microcantilever Designs for Biosensors

PubMed Central

Ansari, Mohd Zahid; Cho, Chongdu

2013-01-01

This study proposes new microcantilever designs in slotted step configuration to improve the S/N ratio of surface stress-based sensors used in physical, chemical, biochemical and biosensor applications. The cantilevers are made of silicon dioxide with a u-shaped silicon piezoresistor in p-doped. The cantilever step length and piezoresistor length is varied along with the operating voltage to characterise the surface stress sensitivity and thermal drifting sensitivity of the cantilevers when used as immunosensor. The numerical analysis is performed using ANSYS Multiphysics. Results show the surface stress sensitivity and the S/N ratio of the slotted step cantilevers is improved by more than 32% and 22%, respectively, over its monolithic counterparts. PMID:23535637

Designing a highly active soluble PQQ-glucose dehydrogenase for efficient glucose biosensors and biofuel cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Durand, Fabien; Stines-Chaumeil, Claire; Flexer, Victoria

2010-11-26

Research highlights: {yields} A new mutant of PQQ-GDH designed for glucose biosensors application. {yields} First mutant of PQQ-GDH with higher activity for D-glucose than the Wild type. {yields} Position N428 is a key point to increase the enzyme activity. {yields} Molecular modeling shows that the N428 C mutant displays a better interaction for PQQ than the WT. -- Abstract: We report for the first time a soluble PQQ-glucose dehydrogenase that is twice more active than the wild type for glucose oxidation and was obtained by combining site directed mutagenesis, modelling and steady-state kinetics. The observed enhancement is attributed to amore » better interaction between the cofactor and the enzyme leading to a better electron transfer. Electrochemical experiments also demonstrate the superiority of the new mutant for glucose oxidation and make it a promising enzyme for the development of high-performance glucose biosensors and biofuel cells.« less

Analyzing the biosensor signal in flows: studies with glucose optrodes.

PubMed

Kivirand, K; Floren, A; Kagan, M; Avarmaa, T; Rinken, T; Jaaniso, R

2015-01-01

Responses of enzymatic bio-optrodes in flow regime were studied and an original model was proposed with the aim of establishing a reliable method for a quick determination of biosensor signal parameters, applicable for biosensor calibration. A dual-optrode glucose biosensor, comprising of a glucose bio-optrode and a reference oxygen optrode, both placed into identical flow channels, was developed and used as a model system. The signal parameters of this biosensor at different substrate concentrations were not dependent on the speed of the probe flow and could be determined from the initial part of the biosensor transient phase signal, providing a valuable tool for rapid analysis. In addition, the model helped to design the biosensor system with reduced impact of enzyme inactivation to the system stability (20% decrease of the enzyme activity lead to only a 1% decrease of the slope of the calibration curve) and hence significantly prolong the effective lifetime of bio-optrodes. Copyright © 2014 Elsevier B.V. All rights reserved.

Simulations and design of microfabricated interdigitated electrodes for use in a gold nanoparticle enhanced biosensor.

PubMed

Hermansen, Peter; MacKay, Scott; Wishart, David; Jie Chen

2016-08-01

Microfabricated interdigitated electrode chips have been designed for use in a unique gold-nanoparticle based biosensor system. The use of these electrodes will allow for simple, accurate, inexpensive, and portable biosensing, with potential applications in diagnostics, medical research, and environmental testing. To determine the optimal design for these electrodes, finite element analysis simulations were carried out using COMSOL Multiphysics software. The results of these simulations determined some of the optimal design parameters for microfabricating interdigitated electrodes as well as predicting the effects of different electrode materials. Finally, based on the results of these simulations two different kinds of interdigitated electrode chips were made using photolithography.

Investigating the effect of design parameters on the response time of a highly sensitive microbial hydrogen sulfide biosensor based on oxygen consumption.

PubMed

Vosoughi, Amin; Yazdian, Fatemeh; Amoabediny, Ghassem; Hakim, Maziar

2015-08-15

A novel hydrogen sulfide microbial biosensor was developed based on investigating the influence of four design parameters: cell concentration, immobilization bed type, hydrogen sulfide concentration, and geometrical shape of the biosensor. Thiobacillus thioparus was used as the recognition element and it was immobilized on sodium alginate as well as agarose bed. The results were optimized by the application of statistical optimization software based on response time of the system. Oxygen reduction was considered as the detection sign. Sodium alginate solution with a concentration of 2.3% (w/v) and optical density of 10 at 605 nm was found as the optimum conditions for immobilization with response time of 72s . Optimum response time of immobilized T. thioparus on agarose was also found equal to 120 s at agarose concentration of 1.2% (w/v) and optical density of 10.83. Performance of the biosensor in different temperatures, pH and agitation speeds was also analyzed. The designed biosensor could detect concentrations of hydrogen sulfide as low as 0.5 ppm. T. thioparus could retain 99% of the original activity in both systems, after ten days passing the fabrication. A fractal analysis was also done theoretically to investigate the diffusion of oxygen in immobilized cells which showed a satisfactory value of oxygen take up by the immobilized cells. Copyright © 2015 Elsevier B.V. All rights reserved.

Biosensors of bacterial cells.

PubMed

Burlage, Robert S; Tillmann, Joshua

2017-07-01

Biosensors are devices which utilize both an electrical component (transducer) and a biological component to study an environment. They are typically used to examine biological structures, organisms and processes. The field of biosensors has now become so large and varied that the technology can often seem impenetrable. Yet the principles which underlie the technology are uncomplicated, even if the details of the mechanisms are elusive. In this review we confine our analysis to relatively current advancements in biosensors for the detection of whole bacterial cells. This includes biosensors which rely on an added labeled component and biosensors which do not have a labeled component and instead detect the binding event or bound structure on the transducer. Methods to concentrate the bacteria prior to biosensor analysis are also described. The variety of biosensor types and their actual and potential uses are described. Copyright © 2016 Elsevier B.V. All rights reserved.

Fiber Optic Surface Plasmon Resonance-Based Biosensor Technique: Fabrication, Advancement, and Application.

PubMed

Liang, Gaoling; Luo, Zewei; Liu, Kunping; Wang, Yimin; Dai, Jianxiong; Duan, Yixiang

2016-05-03

Fiber optic-based biosensors with surface plasmon resonance (SPR) technology are advanced label-free optical biosensing methods. They have brought tremendous progress in the sensing of various chemical and biological species. This review summarizes four sensing configurations (prism, grating, waveguide, and fiber optic) with two ways, attenuated total reflection (ATR) and diffraction, to excite the surface plasmons. Meanwhile, the designs of different probes (U-bent, tapered, and other probes) are also described. Finally, four major types of biosensors, immunosensor, DNA biosensor, enzyme biosensor, and living cell biosensor, are discussed in detail for their sensing principles and applications. Future prospects of fiber optic-based SPR sensor technology are discussed.

Electrochemical Aptamer Scaffold Biosensors for Detection of Botulism and Ricin Proteins.

PubMed

Daniel, Jessica; Fetter, Lisa; Jett, Susan; Rowland, Teisha J; Bonham, Andrew J

2017-01-01

Electrochemical DNA (E-DNA) biosensors enable the detection and quantification of a variety of molecular targets, including oligonucleotides, small molecules, heavy metals, antibodies, and proteins. Here we describe the design, electrode preparation and sensor attachment, and voltammetry conditions needed to generate and perform measurements using E-DNA biosensors against two protein targets, the biological toxins ricin and botulinum neurotoxin. This method can be applied to generate E-DNA biosensors for the detection of many other protein targets, with potential advantages over other systems including sensitive detection limits typically in the nanomolar range, real-time monitoring, and reusable biosensors.

Cholinesterase-based biosensors.

PubMed

Štěpánková, Šárka; Vorčáková, Katarína

2016-01-01

Recently, cholinesterase-based biosensors are widely used for assaying anticholinergic compounds. Primarily biosensors based on enzyme inhibition are useful analytical tools for fast screening of inhibitors, such as organophosphates and carbamates. The present review is aimed at compilation of the most important facts about cholinesterase based biosensors, types of physico-chemical transduction, immobilization strategies and practical applications.

Optical properties of nanowire metamaterials with gain

NASA Astrophysics Data System (ADS)

Lima, Joaquim; Adam, Jost; Rego, Davi; Esquerre, Vitaly; Bordo, Vladimir

2016-11-01

The transmittance, reflectance and absorption of a nanowire metamaterial with optical gain are numerically simulated and investigated. It is assumed that the metamaterial is represented by aligned silver nanowires embedded into a semiconductor matrix, made of either silicon or gallium phosphide. The gain in the matrix is modeled by adding a negative imaginary part to the dielectric function of the semiconductor. It is found that the optical coefficients of the metamaterial depend on the gain magnitude in a non-trivial way: they can both increase and decrease with gain depending on the lattice constant of the metamaterial. This peculiar behavior is explained by the field redistribution between the lossy metal nanowires and the amplifying matrix material. These findings are significant for a proper design of nanowire metamaterials with low optical losses for diverse applications.

Nanowire nanocomputer as a finite-state machine.

PubMed

Yao, Jun; Yan, Hao; Das, Shamik; Klemic, James F; Ellenbogen, James C; Lieber, Charles M

2014-02-18

Implementation of complex computer circuits assembled from the bottom up and integrated on the nanometer scale has long been a goal of electronics research. It requires a design and fabrication strategy that can address individual nanometer-scale electronic devices, while enabling large-scale assembly of those devices into highly organized, integrated computational circuits. We describe how such a strategy has led to the design, construction, and demonstration of a nanoelectronic finite-state machine. The system was fabricated using a design-oriented approach enabled by a deterministic, bottom-up assembly process that does not require individual nanowire registration. This methodology allowed construction of the nanoelectronic finite-state machine through modular design using a multitile architecture. Each tile/module consists of two interconnected crossbar nanowire arrays, with each cross-point consisting of a programmable nanowire transistor node. The nanoelectronic finite-state machine integrates 180 programmable nanowire transistor nodes in three tiles or six total crossbar arrays, and incorporates both sequential and arithmetic logic, with extensive intertile and intratile communication that exhibits rigorous input/output matching. Our system realizes the complete 2-bit logic flow and clocked control over state registration that are required for a finite-state machine or computer. The programmable multitile circuit was also reprogrammed to a functionally distinct 2-bit full adder with 32-set matched and complete logic output. These steps forward and the ability of our unique design-oriented deterministic methodology to yield more extensive multitile systems suggest that proposed general-purpose nanocomputers can be realized in the near future.

Nanowire nanocomputer as a finite-state machine

PubMed Central

Yao, Jun; Yan, Hao; Das, Shamik; Klemic, James F.; Ellenbogen, James C.; Lieber, Charles M.

2014-01-01

Implementation of complex computer circuits assembled from the bottom up and integrated on the nanometer scale has long been a goal of electronics research. It requires a design and fabrication strategy that can address individual nanometer-scale electronic devices, while enabling large-scale assembly of those devices into highly organized, integrated computational circuits. We describe how such a strategy has led to the design, construction, and demonstration of a nanoelectronic finite-state machine. The system was fabricated using a design-oriented approach enabled by a deterministic, bottom–up assembly process that does not require individual nanowire registration. This methodology allowed construction of the nanoelectronic finite-state machine through modular design using a multitile architecture. Each tile/module consists of two interconnected crossbar nanowire arrays, with each cross-point consisting of a programmable nanowire transistor node. The nanoelectronic finite-state machine integrates 180 programmable nanowire transistor nodes in three tiles or six total crossbar arrays, and incorporates both sequential and arithmetic logic, with extensive intertile and intratile communication that exhibits rigorous input/output matching. Our system realizes the complete 2-bit logic flow and clocked control over state registration that are required for a finite-state machine or computer. The programmable multitile circuit was also reprogrammed to a functionally distinct 2-bit full adder with 32-set matched and complete logic output. These steps forward and the ability of our unique design-oriented deterministic methodology to yield more extensive multitile systems suggest that proposed general-purpose nanocomputers can be realized in the near future. PMID:24469812

Recent research trends of radio-frequency biosensors for biomolecular detection.

PubMed

Lee, Hee-Jo; Yook, Jong-Gwan

2014-11-15

This article reviews radio-frequency (RF) biosensors based on passive and/or active devices and circuits. In particular, we focus on RF biosensors designed for detection of various biomolecules such as biotin-streptavidin, DNA hybridization, IgG, and glucose. The performance of these biosensors has been enhanced by the introduction of various sensing schemes with diverse nanomaterials (e.g., carbon nanotubes, graphene oxide, magnetic and gold nanoparticles, etc.). In addition, the RF biosensing platforms that can be associated with an RF active system are discussed. Finally, the challenges of RF biosensors are presented and suggestions are made for their future direction and prospects. Copyright © 2014 Elsevier B.V. All rights reserved.

Resonant efficiency improvement design of piezoelectric biosensor for bacteria gravimetric sensing.

PubMed

Tsai, Jang-Zern; Chen, Ching-Jung; Shie, Dung-Ting; Liu, Jen-Tsai

2014-01-01

The piezoelectric biosensor have been widely used in ultra-small mass detection of biomolecular, based on PZT piezoelectric material can create a variety of compositions geometrically; it could widely develop a high-frequency resonator and measure the change of the slightest mass while improve the limited detection simultaneously. Therefore, the piezoelectric biosensor of this study was fabricated by a spin-coating method and backside etching process for improving the characteristic of piezoelectric biosensor. The result exhibited that the 250 μm × 250 μm working size has the most favorable piezoelectric characteristic. The tunability was approximately 38.56 % and it showed that reducing the substrate thickness could obtain a clear resonance signal in a range of 60 to 380 MHz. In theory calculated for gravimetric sensing, it could achieve 0.1 ng sensing sensitivity. In gravimetric sensing, the sensing range was between 50,000~100,000 CFU/ml. Sensing range was lower in clinical urinary tract infection (100,000 CFU/ml), thus demonstrating its usefulness for preventive medicine. It can understand the piezoelectric sensor of this study has potential application in the future for biomedical gravimetric sensing.

Silicon nanowire based biosensing platform for electrochemical sensing of Mebendazole drug activity on breast cancer cells.

PubMed

Shashaani, Hani; Faramarzpour, Mahsa; Hassanpour, Morteza; Namdar, Nasser; Alikhani, Alireza; Abdolahad, Mohammad

2016-11-15

Electrochemical approaches have played crucial roles in bio sensing because of their Potential in achieving sensitive, specific and low-cost detection of biomolecules and other bio evidences. Engineering the electrochemical sensing interface with nanomaterials tends to new generations of label-free biosensors with improved performances in terms of sensitive area and response signals. Here we applied Silicon Nanowire (SiNW) array electrodes (in an integrated architecture of working, counter and reference electrodes) grown by low pressure chemical vapor deposition (LPCVD) system with VLS procedure to electrochemically diagnose the presence of breast cancer cells as well as their response to anticancer drugs. Mebendazole (MBZ), has been used as antitubulin drug. It perturbs the anodic/cathodic response of the cell covered biosensor by releasing Cytochrome C in cytoplasm. Reduction of cytochrome C would change the ionic state of the cells monitored by SiNW biosensor. By applying well direct bioelectrical contacts with cancer cells, SiNWs can detect minor signal transduction and bio recognition events, resulting in precise biosensing. Our device detected the trace of MBZ drugs (with the concentration of 2nM) on electrochemical activity MCF-7 cells. Also, experimented biological analysis such as confocal and Flowcytometry assays confirmed the electrochemical results. Copyright © 2016 Elsevier B.V. All rights reserved.

Biosensor for remote monitoring of airborne toxins

NASA Astrophysics Data System (ADS)

Knopf, George K.; Bassi, Amarjeet S.; Singh, Shikha; Macleod, Roslyn

1999-12-01

The rapid detection of toxic contaminants released into the air by chemical processing facilities is a high priority for many manufacturers. This paper describes a novel biosensor for the remote monitoring of toxic sites. The proposed biosensor is a measurement system that employs immobilized luminescent Vibrio fisheri bacteria to detect airborne contaminants. The presence of toxic chemicals will lead to a detectable decrease in the intensity of light produced by the bacteria. Both cellular and environmental factors control the bioluminescence of these bacteria. Important design factors are the appropriate cell growth media, environmental toxicity, oxygen and cell concentrations. The luminescent bacteria are immobilized on polyvinyl alcohol (PVA) gels and placed inside a specially constructed, miniature flow cell which houses a transducer, power source, and transmitter to convert the light signal information into radio frequencies that are picked up by a receiver at a remote location. The biosensor prototype is designed to function either as a single unit mounted on an exploratory robot or numerous units spatially distributed throughout a contaminated environment for remote sensing applications.

Functionalization of monolithic and porous three-dimensional graphene by one-step chitosan electrodeposition for enzymatic biosensor.

PubMed

Liu, Jiyang; Wang, Xiaohui; Wang, Tianshu; Li, Dan; Xi, Fengna; Wang, Jin; Wang, Erkang

2014-11-26

Biological modification of monolithic and porous 3D graphene is of great significance for extending its application in fabricating highly sensitive biosensors. The present work reports on the first biofunctionalization of monolithic and freestanding 3D graphene foam for one-step preparation of reagentless enzymatic biosensors by controllable chitosan (CS) electrodeposition technology. Using a homogeneous three-component electrodeposition solution containing a ferrocene (Fc) grafted CS hybrid (Fc-CS), glucose oxidase (GOD), and single-walled carbon nanotubes (SWNTs), a homogeneous biocomposite film of Fc-CS/SWNTs/GOD was immobilized on the surface of 3D graphene foam by one-step electrodeposition. The Fc groups grafted on chitosan can be stably immobilized on the 3D graphene surface and keep their original electrochemical activity. The SWNTs doped into the Fc-CS matrix act as a nanowire to facilitate electron transfer and improve the conductivity of the biocomposite film. Combined with the extraordinary properties of 3D graphene foam including large active surface area, high conductivity, and fast mass transport dynamics, the 3D graphene based enzymatic biosensor achieved a large linear range (5.0 μM to 19.8 mM), a low detection limit (1.2 μM), and rapid response (reaching the 95% steady-state response within 8 s) for reagentless detection of glucose in the phosphate buffer solution.

A comparative study of enzyme immobilization strategies for multi-walled carbon nanotube glucose biosensors

NASA Astrophysics Data System (ADS)

Shi, Jin; Claussen, Jonathan C.; McLamore, Eric S.; Haque, Aeraj ul; Jaroch, David; Diggs, Alfred R.; Calvo-Marzal, Percy; Rickus, Jenna L.; Porterfield, D. Marshall

2011-09-01

This work addresses the comparison of different strategies for improving biosensor performance using nanomaterials. Glucose biosensors based on commonly applied enzyme immobilization approaches, including sol-gel encapsulation approaches and glutaraldehyde cross-linking strategies, were studied in the presence and absence of multi-walled carbon nanotubes (MWNTs). Although direct comparison of design parameters such as linear range and sensitivity is intuitive, this comparison alone is not an accurate indicator of biosensor efficacy, due to the wide range of electrodes and nanomaterials available for use in current biosensor designs. We proposed a comparative protocol which considers both the active area available for transduction following nanomaterial deposition and the sensitivity. Based on the protocol, when no nanomaterials were involved, TEOS/GOx biosensors exhibited the highest efficacy, followed by BSA/GA/GOx and TMOS/GOx biosensors. A novel biosensor containing carboxylated MWNTs modified with glucose oxidase and an overlying TMOS layer demonstrated optimum efficacy in terms of enhanced current density (18.3 ± 0.5 µA mM - 1 cm - 2), linear range (0.0037-12 mM), detection limit (3.7 µM), coefficient of variation (2%), response time (less than 8 s), and stability/selectivity/reproducibility. H2O2 response tests demonstrated that the most possible reason for the performance enhancement was an increased enzyme loading. This design is an excellent platform for versatile biosensing applications.

Fabrication of cross-shaped Cu-nanowire resistive memory devices using a rapid, scalable, and designable inorganic-nanowire-digital-alignment technique (Conference Presentation)

NASA Astrophysics Data System (ADS)

Xu, Wentao; Lee, Yeongjun; Min, Sung-Yong; Park, Cheolmin; Lee, Tae-Woo

2016-09-01

Resistive random-access memory (RRAM) is a candidate next generation nonvolatile memory due to its high access speed, high density and ease of fabrication. Especially, cross-point-access allows cross-bar arrays that lead to high-density cells in a two-dimensional planar structure. Use of such designs could be compatible with the aggressive scaling down of memory devices, but existing methods such as optical or e-beam lithographic approaches are too complicated. One-dimensional inorganic nanowires (i-NWs) are regarded as ideal components of nanoelectronics to circumvent the limitations of conventional lithographic approaches. However, post-growth alignment of these i-NWs precisely on a large area with individual control is still a difficult challenge. Here, we report a simple, inexpensive, and rapid method to fabricate two-dimensional arrays of perpendicularly-aligned, individually-conductive Cu-NWs with a nanometer-scale CuxO layer sandwiched at each cross point, by using an inorganic-nanowire-digital-alignment technique (INDAT) and a one-step reduction process. In this approach, the oxide layer is self-formed and patterned, so conventional deposition and lithography are not necessary. INDAT eliminates the difficulties of alignment and scalable fabrication that are encountered when using currently-available techniques that use inorganic nanowires. This simple process facilitates fabrication of cross-point nonvolatile memristor arrays. Fabricated arrays had reproducible resistive switching behavior, high on/off current ratio (Ion/Ioff) 10 6 and extensive cycling endurance. This is the first report of memristors with the resistive switching oxide layer self-formed, self-patterned and self-positioned; we envision that the new features of the technique will provide great opportunities for future nano-electronic circuits.

Programmable nanowire circuits for nanoprocessors.

PubMed

Yan, Hao; Choe, Hwan Sung; Nam, SungWoo; Hu, Yongjie; Das, Shamik; Klemic, James F; Ellenbogen, James C; Lieber, Charles M

2011-02-10

A nanoprocessor constructed from intrinsically nanometre-scale building blocks is an essential component for controlling memory, nanosensors and other functions proposed for nanosystems assembled from the bottom up. Important steps towards this goal over the past fifteen years include the realization of simple logic gates with individually assembled semiconductor nanowires and carbon nanotubes, but with only 16 devices or fewer and a single function for each circuit. Recently, logic circuits also have been demonstrated that use two or three elements of a one-dimensional memristor array, although such passive devices without gain are difficult to cascade. These circuits fall short of the requirements for a scalable, multifunctional nanoprocessor owing to challenges in materials, assembly and architecture on the nanoscale. Here we describe the design, fabrication and use of programmable and scalable logic tiles for nanoprocessors that surmount these hurdles. The tiles were built from programmable, non-volatile nanowire transistor arrays. Ge/Si core/shell nanowires coupled to designed dielectric shells yielded single-nanowire, non-volatile field-effect transistors (FETs) with uniform, programmable threshold voltages and the capability to drive cascaded elements. We developed an architecture to integrate the programmable nanowire FETs and define a logic tile consisting of two interconnected arrays with 496 functional configurable FET nodes in an area of ∼960 μm(2). The logic tile was programmed and operated first as a full adder with a maximal voltage gain of ten and input-output voltage matching. Then we showed that the same logic tile can be reprogrammed and used to demonstrate full-subtractor, multiplexer, demultiplexer and clocked D-latch functions. These results represent a significant advance in the complexity and functionality of nanoelectronic circuits built from the bottom up with a tiled architecture that could be cascaded to realize fully integrated

One step biofunctionalized electrospun multiwalled carbon nanotubes embedded zinc oxide nanowire interface for highly sensitive detection of carcinoma antigen-125.

PubMed

Paul, K Brince; Singh, Vikrant; Vanjari, Siva Rama Krishna; Singh, Shiv Govind

2017-02-15

Ovarian cancer is the most leading cause of cancer-related death in women . The carcinoma antigen-125, which is found on the surface of many ovarian cancer cells is known to be a gold standard clinical biomarker associated with life-threatening gynecological malignancy. In this work, we demonstrate a novel biosensor platform based on multiwalled carbon nanotubes embedded zinc oxide nanowire for the ultrasensitive detection of carcinoma antigen-125. Label free detection of the carcinoma antigen-125 was accomplished by differential voltammetry technique that demonstrated excellent sensitivity (90.14µA/(U/mL)/cm 2 ) with a detection limit of 0.00113UmL -1 concentration. The fabricated immunosensor exhibits good performance with wider detection range (0.001UmL -1 -1kUmL -1 ), reproducibility, selectivity, acceptable stability, and thus is a potential cost-effective methodology for point-of-care diagnosis. The multiwalled carbon nanotubes (MWCNTs) embedded highly oriented zinc oxide (ZnO) nanowires were synthesized by simple, low cost electrospinning technique. Compared to pure ZnO nanowires, electrochemical activity of MWCNTs embedded ZnO nanowires was found to be much higher. The calcination temperature was optimized to avoid any decomposition of the CNTs and to obtain multiwalled carbon nanotubes embedded highly crystalline ZnO nanowires. The salient feature of this biosensing platform is that one step calcination process is enough to create the functional groups on MWCNT-ZnO nanowire surface that are effective for the covalent conjugation of antibody without further surface modification. To the best of our knowledge, this is the first report on MWCNT-ZnO nanowire based immunosensor explored for the detection of cancer biomarker. Copyright © 2016 Elsevier B.V. All rights reserved.

GMR-based PhC biosensor: FOM analysis and experimental studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Syamprasad, Jagadeesh; Narayanan, Roshni; Joseph, Joby

2014-02-20

Guided Mode Resonance based Photonic crystal biosensor has a lot of potential applications. In our work, we are trying to improve their figure of merit values in order to achieve an optimum level through design and fabrication techniques. A robust and low-cost alternative for current biosensors is also explored through this research.

Resonance phenomenon of the ATP motor as an ultrasensitive biosensor.

PubMed

Wang, Peirong; Zhang, Xiaoguang; Zhang, Xu; Wang, Xia; Li, Xueren; Yue, Jiachang

2012-09-28

We designed a rotary biosensor as a damping effector, with the rotation of the F(0)F(1)-ATPase driven by Adenosine Triphosphate (ATP) synthesis being indicated by the fluorescence intensity and a damping effect force being induced by the binding of an RNA molecule to its probe on the rotary biosensor. We found that the damping effect could contribute to the resonance phenomenon and energy transfer process of our rotary biosensor in the liquid phase. This result indicates that the ability of the rotary motor to operate in the vibration harmonic mode depends on the environmental conditions and mechanism in that a few molecules of the rotary biosensor could induce all of the sensor molecules to fluoresce together. These findings contribute to the theory study of the ATPase motor and future development of biosensors for ultrasensitive detection. Copyright © 2012 Elsevier Inc. All rights reserved.

Spatially resolved Hall effect measurement in a single semiconductor nanowire.

PubMed

Storm, Kristian; Halvardsson, Filip; Heurlin, Magnus; Lindgren, David; Gustafsson, Anders; Wu, Phillip M; Monemar, Bo; Samuelson, Lars

2012-11-01

Efficient light-emitting diodes and photovoltaic energy-harvesting devices are expected to play an important role in the continued efforts towards sustainable global power consumption. Semiconductor nanowires are promising candidates as the active components of both light-emitting diodes and photovoltaic cells, primarily due to the added freedom in device design offered by the nanowire geometry. However, for nanowire-based components to move past the proof-of-concept stage and be implemented in production-grade devices, it is necessary to precisely quantify and control fundamental material properties such as doping and carrier mobility. Unfortunately, the nanoscale geometry that makes nanowires interesting for applications also makes them inherently difficult to characterize. Here, we report a method to carry out Hall measurements on single core-shell nanowires. Our technique allows spatially resolved and quantitative determination of the carrier concentration and mobility of the nanowire shell. As Hall measurements have previously been completely unavailable for nanowires, the experimental platform presented here should facilitate the implementation of nanowires in advanced practical devices.

Semiconductor nanowires: A platform for nanoscience and nanotechnology

PubMed Central

Lieber, Charles M.

2012-01-01

Advances in nanoscience and nanotechnology critically depend on the development of nanostructures whose properties are controlled during synthesis. We focus on this critical concept using semiconductor nanowires, which provide the capability through design and rational synthesis to realize unprecedented structural and functional complexity in building blocks as a platform material. First, a brief review of the synthesis of complex modulated nanowires in which rational design and synthesis can be used to precisely control composition, structure, and, most recently, structural topology is discussed. Second, the unique functional characteristics emerging from our exquisite control of nanowire materials are illustrated using several selected examples from nanoelectronics and nano-enabled energy. Finally, the remarkable power of nanowire building blocks is further highlighted through their capability to create unprecedented, active electronic interfaces with biological systems. Recent work pushing the limits of both multiplexed extracellular recording at the single-cell level and the first examples of intracellular recording is described, as well as the prospects for truly blurring the distinction between nonliving nanoelectronic and living biological systems. PMID:22707850

Biosensor development.

PubMed

Ziegler, C; Göpel, W

1998-10-01

Current biosensor developments can be summarised by different trends. For traditional enzymatic biosensors such as glucose sensors, steady improvements of well known basic principles have been made in order to achieve better sensor stability. On the other hand, new affinity sensors such as nucleic acid sensors, transmembrane sensors, and sensors utilising whole cells or even cell networks have become of increasing interest. New ways to miniaturise biosensors and to control their interfaces down to the molecular level have been introduced (the bioelectronics approach). High-throughput screening based on various signal transduction principles has become of increasing importance.

Biosensor technology for pesticides--a review.

PubMed

Verma, Neelam; Bhardwaj, Atul

2015-03-01

Pesticides, due to their lucrative outcomes, are majorly implicated in agricultural fields for crop production enhancement. Due to their pest removal properties, pesticides of various classes have been designed to persist in the environment over a longer duration after their application to achieve maximum effectiveness. Apart from their recalcitrant structure and agricultural benefits, pesticides also impose acute toxicological effects onto the other various life forms. Their accumulation in the living system may prove to be detrimental if established in higher concentrations. Thus, their prompt and accurate analysis is a crucial matter of concern. Conventional techniques like chromatographic techniques (HPLC, GC, etc.) used for pesticides detection are associated with various limitations like stumpy sensitivity and efficiency, time consumption, laboriousity, requirement of expensive equipments and highly trained technicians, and many more. So there is a need to recruit the methods which can detect these neurotoxic compounds sensitively, selectively, rapidly, and easily in the field. Present work is a brief review of the pesticide effects, their current usage scenario, permissible limits in various food stuffs and 21st century advancements of biosensor technology for pesticide detection. Due to their exceptional performance capabilities, easiness in operation and on-site working, numerous biosensors have been developed for bio-monitoring of various environmental samples for pesticide evaluation immensely throughout the globe. Till date, based on sensing element (enzyme based, antibody based, etc.) and type of detection method used (Electrochemical, optical, and piezoelectric, etc.), a number of biosensors have been developed for pesticide detection. In present communication, authors have summarized 21st century's approaches of biosensor technology for pesticide detection such as enzyme-based biosensors, immunosensors, aptamers, molecularly imprinted polymers, and

Nanoplasmonic Biosensor Using Localized Surface Plasmon Resonance Spectroscopy for Biochemical Detection.

PubMed

Zhang, Diming; Zhang, Qian; Lu, Yanli; Yao, Yao; Li, Shuang; Liu, Qingjun

2017-01-01

Localized surface plasmon resonance (LSPR) associated with metal nanostructures has developed into a highly useful sensor technique. Optical LSPR spectroscopy of nanostructures often shows sharp absorption and scattering peaks, which can be used to probe several bio-molecular interactions. Here, we report nanoplasmonic biosensors using LSPR on nanocup arrays (nanoCA) to recognize bio-molecular binding for biochemical detection. These sensors can be modified to quantify binding of small molecules to proteins for odorant and explosive detections. Electrochemical LSPR biosensors can also be designed by coupling electrochemistry and LSPR spectroscopy measurements. Multiple sensing information can be obtained and electrochemical LSPR property can be investigated for biosensors. In some applications, the electrochemical LSPR biosensor can be used to quantify immunoreactions and enzymatic activity. The biosensors exhibit better performance than those of conventional optical LSPR measurements. With multi-transducers, the nanoplasmonic biosensor can provide a promising approach for bio-detection in environmental monitoring, healthcare diagnostics, and food quality control.

Biosensor of endotoxin and sepsis

NASA Astrophysics Data System (ADS)

Shao, Yang; Wang, Xiang; Wu, Xi; Gao, Wei; He, Qing-hua; Cai, Shaoxi

2001-09-01

To investigate the relation between biosensor of endotoxin and endotoxin of plasma in sepsis. Method: biosensor of endotoxin was designed with technology of quartz crystal microbalance bioaffinity sensor ligand of endotoxin were immobilized by protein A conjugate. When a sample soliton of plasma containing endotoxin 0.01, 0.03, 0.06, 0.1, 0.5, 1.0Eu, treated with perchloric acid and injected into slot of quartz crystal surface respectively, the ligand was released from the surface of quartz crystal to form a more stable complex with endotoxin in solution. The endotoxin concentration corresponded to the weight change on the crystal surface, and caused change of frequency that occurred when desorbed. The result was biosensor of endotoxin might detect endotoxin of plasma in sepsis, measurements range between 0.05Eu and 0.5Eu in the stop flow mode, measurement range between 0.1Eu and 1Eu in the flow mode. The sensor of endotoxin could detect the endotoxin of plasm rapidly, and use for detection sepsis in clinically.

Photoelectrochemical enzymatic biosensors.

PubMed

Zhao, Wei-Wei; Xu, Jing-Juan; Chen, Hong-Yuan

2017-06-15

Enzymatic biosensors have been valuable bioanalytical devices for analysis of diverse targets in disease diagnosis, biological and biomedical research, etc. Photoelectrochemical (PEC) bioanalysis is a recently emerged method that promptly becoming a subject of new research interests due to its attractive potential for future bioanalysis with high sensitivity and specificity. PEC enzymatic biosensors integrate the inherent sensitivities of PEC bioanalysis and the selectivity of enzymes and thus share their both advantages. Currently, PEC enzymatic biosensors have become a hot topic of significant research and the recent impetus has grown rapidly as demonstrated by increased research papers. Given the pace of advances in this area, this review will make a thorough discussion and survey on the fundamentals, sensing strategies, applications and the state of the art in PEC enzymatic biosensors, followed by future prospects based on our own opinions. We hope this work could provide an accessible introduction to PEC enzymatic biosensors for any scientist. Copyright © 2016 Elsevier B.V. All rights reserved.

Evaluating Plasmonic Transport in Current-carrying Silver Nanowires

PubMed Central

Song, Mingxia; Stolz, Arnaud; Zhang, Douguo; Arocas, Juan; Markey, Laurent; Colas des Francs, Gérard; Dujardin, Erik; Bouhelier, Alexandre

2013-01-01

Plasmonics is an emerging technology capable of simultaneously transporting a plasmonic signal and an electronic signal on the same information support1,2,3. In this context, metal nanowires are especially desirable for realizing dense routing networks4. A prerequisite to operate such shared nanowire-based platform relies on our ability to electrically contact individual metal nanowires and efficiently excite surface plasmon polaritons5 in this information support. In this article, we describe a protocol to bring electrical terminals to chemically-synthesized silver nanowires6 randomly distributed on a glass substrate7. The positions of the nanowire ends with respect to predefined landmarks are precisely located using standard optical transmission microscopy before encapsulation in an electron-sensitive resist. Trenches representing the electrode layout are subsequently designed by electron-beam lithography. Metal electrodes are then fabricated by thermally evaporating a Cr/Au layer followed by a chemical lift-off. The contacted silver nanowires are finally transferred to a leakage radiation microscope for surface plasmon excitation and characterization8,9. Surface plasmons are launched in the nanowires by focusing a near infrared laser beam on a diffraction-limited spot overlapping one nanowire extremity5,9. For sufficiently large nanowires, the surface plasmon mode leaks into the glass substrate9,10. This leakage radiation is readily detected, imaged, and analyzed in the different conjugate planes in leakage radiation microscopy9,11. The electrical terminals do not affect the plasmon propagation. However, a current-induced morphological deterioration of the nanowire drastically degrades the flow of surface plasmons. The combination of surface plasmon leakage radiation microscopy with a simultaneous analysis of the nanowire electrical transport characteristics reveals the intrinsic limitations of such plasmonic circuitry. PMID:24378340

SNSPD with parallel nanowires (Conference Presentation)

NASA Astrophysics Data System (ADS)

Ejrnaes, Mikkel; Parlato, Loredana; Gaggero, Alessandro; Mattioli, Francesco; Leoni, Roberto; Pepe, Giampiero; Cristiano, Roberto

2017-05-01

Superconducting nanowire single-photon detectors (SNSPDs) have shown to be promising in applications such as quantum communication and computation, quantum optics, imaging, metrology and sensing. They offer the advantages of a low dark count rate, high efficiency, a broadband response, a short time jitter, a high repetition rate, and no need for gated-mode operation. Several SNSPD designs have been proposed in literature. Here, we discuss the so-called parallel nanowires configurations. They were introduced with the aim of improving some SNSPD property like detection efficiency, speed, signal-to-noise ratio, or photon number resolution. Although apparently similar, the various parallel designs are not the same. There is no one design that can improve the mentioned properties all together. In fact, each design presents its own characteristics with specific advantages and drawbacks. In this work, we will discuss the various designs outlining peculiarities and possible improvements.

Ratiometric Matryoshka biosensors from a nested cassette of green- and orange-emitting fluorescent proteins.

PubMed

Ast, Cindy; Foret, Jessica; Oltrogge, Luke M; De Michele, Roberto; Kleist, Thomas J; Ho, Cheng-Hsun; Frommer, Wolf B

2017-09-05

Sensitivity, dynamic and detection range as well as exclusion of expression and instrumental artifacts are critical for the quantitation of data obtained with fluorescent protein (FP)-based biosensors in vivo. Current biosensors designs are, in general, unable to simultaneously meet all these criteria. Here, we describe a generalizable platform to create dual-FP biosensors with large dynamic ranges by employing a single FP-cassette, named GO-(Green-Orange) Matryoshka. The cassette nests a stable reference FP (large Stokes shift LSSmOrange) within a reporter FP (circularly permuted green FP). GO- Matryoshka yields green and orange fluorescence upon blue excitation. As proof of concept, we converted existing, single-emission biosensors into a series of ratiometric calcium sensors (MatryoshCaMP6s) and ammonium transport activity sensors (AmTryoshka1;3). We additionally identified the internal acid-base equilibrium as a key determinant of the GCaMP dynamic range. Matryoshka technology promises flexibility in the design of a wide spectrum of ratiometric biosensors and expanded in vivo applications.Single fluorescent protein biosensors are susceptible to expression and instrumental artifacts. Here Ast et al. describe a dual fluorescent protein design whereby a reference fluorescent protein is nested within a reporter fluorescent protein to control for such artifacts while preserving sensitivity and dynamic range.

Biosensor commercialization strategy - a theoretical approach.

PubMed

Lin, Chin-Tsai; Wang, Su-Man

2005-01-01

Biosensors are analytical devices, which use biological interactions to provide either qualitative or quantitative results. They are extensively employed in many fields such as clinical diagnosis and biomedicine, military applications, anti-terrorism, farm, garden and veterinary analysis, process control, fermentation control and analysis, pharmaceutical and drug analysis, food and drink production and analysis, pollution control and monitoring, microbiology, bacterial and viral analysis, mining, and industrial and toxic gases. The biosensor market has significantly increased and will be mushrooming in the next decade. The total biosensor market is estimated to be 10.8 billion dollars by 2007. The emerging biosensor market presents both opportunities and obstacles to start-up biosensor entrepreneurs. The major challenge and threat for these entrepreneurs is how to predict the biosensor market and how to convert promising biosensor technology into commercialized biosensors. By adopting a simple commercialization strategy framework, we identify two key elements of biosensor commercialization strategy: excludability and complementary asset. We further divide biosensor commercialization environments into four distinct sub-environments: the Attacker's Advantage, Reputation-Based Idea Trading, Greenfield Competition and Ideas Factories. This paper explains how the interaction between these two key elements shapes biosensor commercialization strategy and biosensor industry dynamics. This paper also discusses alternative commercialization strategies for each specific commercialization environment and how to choose from these alternatives. The analysis of this study further provides a good reference for start-up biosensor entrepreneurs to formulate effective biosensor commercialization strategy.

Electrochemical biosensors for hormone analyses.

PubMed

Bahadır, Elif Burcu; Sezgintürk, Mustafa Kemal

2015-06-15

Electrochemical biosensors have a unique place in determination of hormones due to simplicity, sensitivity, portability and ease of operation. Unlike chromatographic techniques, electrochemical techniques used do not require pre-treatment. Electrochemical biosensors are based on amperometric, potentiometric, impedimetric, and conductometric principle. Amperometric technique is a commonly used one. Although electrochemical biosensors offer a great selectivity and sensitivity for early clinical analysis, the poor reproducible results, difficult regeneration steps remain primary challenges to the commercialization of these biosensors. This review summarizes electrochemical (amperometric, potentiometric, impedimetric and conductometric) biosensors for hormone detection for the first time in the literature. After a brief description of the hormones, the immobilization steps and analytical performance of these biosensors are summarized. Linear ranges, LODs, reproducibilities, regenerations of developed biosensors are compared. Future outlooks in this area are also discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

Directed branch growth in aligned nanowire arrays.

PubMed

Beaudry, Allan L; LaForge, Joshua M; Tucker, Ryan T; Sorge, Jason B; Adamski, Nicholas L; Li, Peng; Taschuk, Michael T; Brett, Michael J

2014-01-01

Branch growth is directed along two, three, or four in-plane directions in vertically aligned nanowire arrays using vapor-liquid-solid glancing angle deposition (VLS-GLAD) flux engineering. In this work, a dynamically controlled collimated vapor flux guides branch placement during the self-catalyzed epitaxial growth of branched indium tin oxide nanowire arrays. The flux is positioned to grow branches on select nanowire facets, enabling fabrication of aligned nanotree arrays with L-, T-, or X-branching. In addition, a flux motion algorithm is designed to selectively elongate branches along one in-plane axis. Nanotrees are found to be aligned across large areas by X-ray diffraction pole figure analysis and through branch length and orientation measurements collected over 140 μm(2) from scanning electron microscopy images for each array. The pathway to guided assembly of nanowire architectures with controlled interconnectivity in three-dimensions using VLS-GLAD is discussed.

Room-temperature lasing in a single nanowire with quantum dots

NASA Astrophysics Data System (ADS)

Tatebayashi, Jun; Kako, Satoshi; Ho, Jinfa; Ota, Yasutomo; Iwamoto, Satoshi; Arakawa, Yasuhiko

2015-08-01

Semiconductor nanowire lasers are promising as ultrasmall, highly efficient coherent light emitters in the fields of nanophotonics, nano-optics and nanobiotechnology. Although there have been several demonstrations of nanowire lasers using homogeneous bulk gain materials or multi-quantum-wells/disks, it is crucial to incorporate lower-dimensional quantum nanostructures into the nanowire to achieve superior device performance in relation to threshold current, differential gain, modulation bandwidth and temperature sensitivity. The quantum dot is a useful and essential nanostructure that can meet these requirements. However, difficulties in forming stacks of quantum dots in a single nanowire hamper the realization of lasing operation. Here, we demonstrate room-temperature lasing of a single nanowire containing 50 quantum dots by properly designing the nanowire cavity and tailoring the emission energy of each dot to enhance the optical gain. Our demonstration paves the way toward ultrasmall lasers with extremely low power consumption for integrated photonic systems.

Artificially modified magnetic anisotropy in interconnected nanowire networks.

PubMed

Araujo, Elsie; Encinas, Armando; Velázquez-Galván, Yenni; Martínez-Huerta, Juan Manuel; Hamoir, Gaël; Ferain, Etienne; Piraux, Luc

2015-01-28

Interconnected or crossed magnetic nanowire networks have been fabricated by electrodeposition into a polycarbonate template with crossed cylindrical nanopores oriented ±30° with respect to the surface normal. Tailor-made nanoporous polymer membranes have been designed by performing a double energetic heavy ion irradiation with fixed incidence angles. The Ni and Ni/NiFe nanowire networks have been characterized by magnetometry as well as ferromagnetic resonance and compared with parallel nanowire arrays of the same diameter and density. The most interesting feature of these nanostructured materials is a significant reduction of the magnetic anisotropy when the external field is applied perpendicular and parallel to the plane of the sample. This effect is attributed to the relative orientation of the nanowire axes with the applied field. Moreover, the microwave transmission spectra of these nanowire networks display an asymmetric linewidth broadening, which may be interesting for the development of low-pass filters. Nanoporous templates made of well-defined nanochannel network constitute an interesting approach to fabricate materials with controlled anisotropy and microwave absorption properties that can be easily modified by adjusting the relative orientation of the nanochannels, pore sizes and material composition along the length of the nanowire.

Recent advances in transition-metal dichalcogenides based electrochemical biosensors: A review.

PubMed

Wang, Yi-Han; Huang, Ke-Jing; Wu, Xu

2017-11-15

Layered transition metal dichalcogenides (TMDCs) comprise a category of two-dimensional (2D) materials that offer exciting properties, including large surface area, metallic and semi-conducting electrical capabilities, and intercalatable morphologies. Biosensors employ biological molecules to recognize the target and utilize output elements which can translate the biorecognition event into electrical, optical or mass-sensitive signals to determine the quantities of the target. TMDCs nanomaterials have been widely applied in various electrochemical biosensors with high sensitivity and selectivity. The marriage of TMDCs and electrochemical biosensors has created many productive sensing strategies for applications in the areas of clinical diagnosis, environmental monitoring and food safety. In recent years, an increasing number of TMDCs-based electrochemical biosensors are reported, suggesting TMDCs offers new possibilities of improving the performance of electrochemical biosensors. This review summarizes recent advances in electrochemical biosensors based on TMDCs for detection of various inorganic and organic analytes in the last five years, including glucose, proteins, DNA, heavy metal, etc. In addition, we also point out the challenges and future perspectives related to the material design and development of TMDCs-based electrochemical biosensors. Copyright © 2017 Elsevier B.V. All rights reserved.

How to design cell-based biosensors using the sol-gel process.

PubMed

Depagne, Christophe; Roux, Cécile; Coradin, Thibaud

2011-05-01

Inorganic gels formed using the sol-gel process are promising hosts for the encapsulation of living organisms and the design of cell-based biosensors. However, the possibility to use the biological activity of entrapped cells as a biological signal requires a good understanding and careful control of the chemical and physical conditions in which the organisms are placed before, during, and after gel formation, and their impact on cell viability. Moreover, it is important to examine the possible transduction methods that are compatible with sol-gel encapsulated cells. Through an updated presentation of the current knowledge in this field and based on selected examples, this review shows how it has been possible to convert a chemical technology initially developed for the glass industry into a biotechnological tool, with current limitations and promising specificities.

Tandem Solar Cells Using GaAs Nanowires on Si: Design, Fabrication, and Observation of Voltage Addition.

PubMed

Yao, Maoqing; Cong, Sen; Arab, Shermin; Huang, Ningfeng; Povinelli, Michelle L; Cronin, Stephen B; Dapkus, P Daniel; Zhou, Chongwu

2015-11-11

Multijunction solar cells provide us a viable approach to achieve efficiencies higher than the Shockley-Queisser limit. Due to their unique optical, electrical, and crystallographic features, semiconductor nanowires are good candidates to achieve monolithic integration of solar cell materials that are not lattice-matched. Here, we report the first realization of nanowire-on-Si tandem cells with the observation of voltage addition of the GaAs nanowire top cell and the Si bottom cell with an open circuit voltage of 0.956 V and an efficiency of 11.4%. Our simulation showed that the current-matching condition plays an important role in the overall efficiency. Furthermore, we characterized GaAs nanowire arrays grown on lattice-mismatched Si substrates and estimated the carrier density using photoluminescence. A low-resistance connecting junction was obtained using n(+)-GaAs/p(+)-Si heterojunction. Finally, we demonstrated tandem solar cells based on top GaAs nanowire array solar cells grown on bottom planar Si solar cells. The reported nanowire-on-Si tandem cell opens up great opportunities for high-efficiency, low-cost multijunction solar cells.

Influence factors of the inter-nanowire thermal contact resistance in the stacked nanowires

NASA Astrophysics Data System (ADS)

Wu, Dongxu; Huang, Congliang; Zhong, Jinxin; Lin, Zizhen

2018-05-01

The inter-nanowire thermal contact resistance is important for tuning the thermal conductivity of a nanocomposite for thermoelectric applications. In this paper, the stacked copper nanowires are applied for studying the thermal contact resistance. The stacked copper nanowires are firstly made by the cold-pressing method, and then the nanowire stacks are treated by sintering treatment. With the effect of the volumetric fraction of nanowires in the stack and the influence of the sintering-temperature on the thermal contact resistance discussed, results show that: The thermal conductivity of the 150-nm copper nanowires can be enlarged almost 2 times with the volumetric fraction increased from 32 to 56% because of the enlarged contact-area and contact number of a copper nanowire. When the sintering temperature increases from 293 to 673 K, the thermal conductivity of the stacked 300-nm nanowires could be enlarged almost 2.5 times by the sintering treatment, because of the improved lattice property of the contact zone. In conclusion, application of a high volumetric fraction or/and a sintering-treatment are effectivity to tune the inter-nanowire thermal contact resistance, and thus to tailor the thermal conductivity of a nanowire network or stack.

Nanocellulose-based biosensors: design, preparation, and activity of peptide-linked cotton cellulose nanocrystals having fluorimetric and colorimetric elastase detection sensitivity

USDA-ARS?s Scientific Manuscript database

Nanocrystalline cellulose is an amphiphilic, high surface area material that can be easily functionalized and is biocom-patible and eco-friendly. It has been used singularly and in combination with other nanomaterials to optimize biosensor design. The attachment of peptides and proteins to nanocryst...

Design of monoalcohol - Copolymer system for high quality silver nanowires.

PubMed

Sugiyama, Shintaro; Yokoyama, Shun; Cuya Huaman, Jhon L; Ida, Shohei; Matsumoto, Takatoshi; Kodama, Daisuke; Sato, Kimitaka; Miyamura, Hiroshi; Hirokawa, Yoshitsugu; Balachandran, Jeyadevan

2018-05-14

Research to improve the dimensional properties of silver nanowires (Ag NWs) for transparent conductive film (TCF) applications are being carried out intensively. However, the protocol for the designed synthesis of high-quality Ag NWs is yet to be developed due to the inadequacy of knowledge on the role of parameters. Here, we attempt to elucidate the role played by the parameters and propose a monoalcohol-copolymer based system for the designed synthesis of Ag NWs superior in quality to the one synthesized using conventional ethylene glycol (EG)-polyvinylpyrrolidone (PVP) system. The key findings of the study are as follows: (1) the solubility of Ag source and the partially formed AgCl particles in monoalcohols was found to play an important role not only in the reduction to metallic Ag but also on the uniaxial growth, (2) the adsorption of capping agents on Ag NWs was carried through O and N atoms in the base molecule and their binding energies indicated that the strength is the key parameter to obtain Ag NWs with high aspect ratio, (3) the properties of nanowire could be enhanced through copolymerization of VP and base molecules that have O- and N-based ligands, and (4) the influence of copolymerization on the physical and chemical properties of the surface active agent has been theoretically and experimentally verified. Consequently, we succeeded in the development of a new technique to synthesize high yield of Ag NWs with improved aspect ratio than EG-PVP system by using benzyl alcohol as reducing solvent and N-vinylpyrrolidone/N,N-diethylaminoethyl metacrylate copolymer as a capping agent. The optical transmittance and electrical resistivity of TCFs prepared using the Ag NWs with an average diameter of 43 nm, and an average length of 13 μm were 98.6% and R: 49.1 Ω/□, respectively. Copyright © 2018 Elsevier Inc. All rights reserved.

Assembling Amperometric Biosensors for Clinical Diagnostics

PubMed Central

Belluzo, María Soledad; Ribone, María Élida; Lagier, Claudia Marina

2008-01-01

Clinical diagnosis and disease prevention routinely require the assessment of species determined by chemical analysis. Biosensor technology offers several benefits over conventional diagnostic analysis. They include simplicity of use, specificity for the target analyte, speed to arise to a result, capability for continuous monitoring and multiplexing, together with the potentiality of coupling to low-cost, portable instrumentation. This work focuses on the basic lines of decisions when designing electron-transfer-based biosensors for clinical analysis, with emphasis on the strategies currently used to improve the device performance, the present status of amperometric electrodes for biomedicine, and the trends and challenges envisaged for the near future. PMID:27879771

Design High-Efficiency III-V Nanowire/Si Two-Junction Solar Cell.

PubMed

Wang, Y; Zhang, Y; Zhang, D; He, S; Li, X

2015-12-01

In this paper, we report the electrical simulation results of a proposed GaInP nanowire (NW)/Si two-junction solar cell. The NW physical dimensions are determined for optimized solar energy absorption and current matching between each subcell. Two key factors (minority carrier lifetime, surface recombination velocity) affecting power conversion efficiency (PCE) of the solar cell are highlighted, and a practical guideline to design high-efficiency two-junction solar cell is thus provided. Considering the practical surface and bulk defects in GaInP semiconductor, a promising PCE of 27.5 % can be obtained. The results depict the usefulness of integrating NWs to construct high-efficiency multi-junction III-V solar cells.

Electrochemical and AFM Characterization of G-Quadruplex Electrochemical Biosensors and Applications

PubMed Central

2018-01-01

Guanine-rich DNA sequences are able to form G-quadruplexes, being involved in important biological processes and representing smart self-assembling nanomaterials that are increasingly used in DNA nanotechnology and biosensor technology. G-quadruplex electrochemical biosensors have received particular attention, since the electrochemical response is particularly sensitive to the DNA structural changes from single-stranded, double-stranded, or hairpin into a G-quadruplex configuration. Furthermore, the development of an increased number of G-quadruplex aptamers that combine the G-quadruplex stiffness and self-assembling versatility with the aptamer high specificity of binding to a variety of molecular targets allowed the construction of biosensors with increased selectivity and sensitivity. This review discusses the recent advances on the electrochemical characterization, design, and applications of G-quadruplex electrochemical biosensors in the evaluation of metal ions, G-quadruplex ligands, and other small organic molecules, proteins, and cells. The electrochemical and atomic force microscopy characterization of G-quadruplexes is presented. The incubation time and cations concentration dependence in controlling the G-quadruplex folding, stability, and nanostructures formation at carbon electrodes are discussed. Different G-quadruplex electrochemical biosensors design strategies, based on the DNA folding into a G-quadruplex, the use of G-quadruplex aptamers, or the use of hemin/G-quadruplex DNAzymes, are revisited. PMID:29666699

Biolayer modeling and optimization for the SPARROW biosensor

NASA Astrophysics Data System (ADS)

Feng, Ke

2007-12-01

Biosensor direct detection of molecular binding events is of significant interest in applications from molecular screening for cancer drug design to bioagent detection for homeland security and defense. The Stacked Planar Affinity Regulated Resonant Optical Waveguide (SPARROW) structure based on coupled waveguides was recently developed to achieve increased sensitivity within a fieldable biosensor device configuration. Under ideal operating conditions, modification of the effective propagation constant of the structure's sensing waveguide through selective attachment of specific targets to probes on the waveguide surface results in a change in the coupling characteristics of the guide over a specifically designed interaction length with the analyte. Monitoring the relative power in each waveguide after interaction enables 'recognition' of those targets which have selectively bound to the surface. However, fabrication tolerances, waveguide interface roughness, biolayer surface roughness and biolayer partial coverage have an effect on biosensor behavior and achievable limit of detection (LOD). In addition to these influences which play a role in device optimization, the influence of the spatially random surface loading of molecular binding events has to be considered, especially for low surface coverage. In this dissertation an analytic model is established for the SPARROW biosensor which accounts for these nonidealities with which the design of the biosensor can be guided and optimized. For the idealized case of uniform waveguide transducer layers and biolayer, both theoretical simulation (analytical expression) and computer simulation (numerical calculation) are completed. For the nonideal case of an inhomogeneous transducer with nonideal waveguide and biolayer surfaces, device output power is affected by such physical influences as surface scattering, coupling length, absorption, and percent coverage of binding events. Using grating and perturbation techniques we

Nanowire Photovoltaic Devices

NASA Technical Reports Server (NTRS)

Forbes, David

2015-01-01

Firefly Technologies, in collaboration with the Rochester Institute of Technology and the University of Wisconsin-Madison, developed synthesis methods for highly strained nanowires. Two synthesis routes resulted in successful nanowire epitaxy: direct nucleation and growth on the substrate and a novel selective-epitaxy route based on nanolithography using diblock copolymers. The indium-arsenide (InAs) nanowires are implemented in situ within the epitaxy environment-a significant innovation relative to conventional semiconductor nanowire generation using ex situ gold nanoparticles. The introduction of these nanoscale features may enable an intermediate band solar cell while simultaneously increasing the effective absorption volume that can otherwise limit short-circuit current generated by thin quantized layers. The use of nanowires for photovoltaics decouples the absorption process from the current extraction process by virtue of the high aspect ratio. While no functional solar cells resulted from this effort, considerable fundamental understanding of the nanowire epitaxy kinetics and nanopatterning process was developed. This approach could, in principle, be an enabling technology for heterointegration of dissimilar materials. The technology also is applicable to virtual substrates. Incorporating nanowires onto a recrystallized germanium/metal foil substrate would potentially solve the problem of grain boundary shunting of generated carriers by restricting the cross-sectional area of the nanowire (tens of nanometers in diameter) to sizes smaller than the recrystallized grains (0.5 to 1 micron(exp 2).

Improvement of up-converting phosphor technology-based biosensor

NASA Astrophysics Data System (ADS)

Xie, Chengke; Huang, Lihua; Zhang, Youbao; Guo, Xiaoxian; Qu, Jianfeng; Huang, Huijie

2008-12-01

A novel biosensor based on up-converting phosphor technology (UPT) was developed several years ago. It is a kind of optical biosensor using up-converting phosphor (UCP) particles as the biological marker. From then on, some improvements have been made for this UPT-based biosensor. The primary aspects of the improvement lie in the control system. On one hand, the hardware of the control system has been optimized, including replacing two single chip microcomputers (SCM) with only one, the optimal design of the keyboard interface circuit and the liquid crystal module (LCM) control circuit et al.. These result in lower power consumption and higher reliability. On the other hand, a novel signal processing algorithm is proposed in this paper, which can improve the automation and operating simplicity of the UPT-based biosensor. It has proved to have high sensitivity (~ng/ml), high stability and good repeatability (CV<5%), which is better than the former system. It can meet the need of some various applications such as rapid immunoassay, chemical and biological detection and so on.

Xanthine oxidase biosensor for monitoring meat spoilage

NASA Astrophysics Data System (ADS)

Vanegas, D. C.; Gomes, C.; McLamore, E. S.

2014-05-01

In this study, we have designed an electrochemical biosensor for real-time detection of specific biomarkers of bacterial metabolism related to meat spoilage (hypoxanthine and xanthine). The selective biosensor was developed by assembling a `sandwich' of nanomaterials and enzymes on a platinum-iridium electrode (1.6 mm tip diameter). The materials deposited on the sensor tip include amorphous platinum nanoclusters (i.e. Pt black), reduced graphene oxide, nanoceria, and xanthine oxidase. Xanthine oxidase was encapsulated in laponite hydrogel and used for the biorecognition of hypoxanthine and xanthine (two molecules involved in the rotting of meat by spoilage microorganisms). The developed biosensor demonstrated good electrochemical performance toward xanthine with sensitivity of 2.14 +/- 1.48 μA/mM, response time of 5.2 +/- 1.5 sec, lower detection limit of 150 +/- 39 nM, and retained at least 88% of its activity after 7 days of continuous use.

Fibroblasts Cultured on Nanowires Exhibit Low Motility, Impaired Cell Division, and DNA Damage

PubMed Central

Persson, Henrik; Købler, Carsten; Mølhave, Kristian; Samuelson, Lars; Tegenfeldt, Jonas O; Oredsson, Stina; Prinz, Christelle N

2013-01-01

Nanowires are commonly used as tools for interfacing living cells, acting as biomolecule-delivery vectors or electrodes. It is generally assumed that the small size of the nanowires ensures a minimal cellular perturbation, yet the effects of nanowires on cell migration and proliferation remain largely unknown. Fibroblast behaviour on vertical nanowire arrays is investigated, and it is shown that cell motility and proliferation rate are reduced on nanowires. Fibroblasts cultured on long nanowires exhibit failed cell division, DNA damage, increased ROS content and respiration. Using focused ion beam milling and scanning electron microscopy, highly curved but intact nuclear membranes are observed, showing no direct contact between the nanowires and the DNA. The nanowires possibly induce cellular stress and high respiration rates, which trigger the formation of ROS, which in turn results in DNA damage. These results are important guidelines to the design and interpretation of experiments involving nanowire-based transfection and electrical characterization of living cells. PMID:23813871

Development and Applications of Portable Biosensors.

PubMed

Srinivasan, Balaji; Tung, Steve

2015-08-01

The significance of microfluidics-based and microelectromechanical systems-based biosensors has been widely acknowledged, and many reviews have explored their potential applications in clinical diagnostics, personalized medicine, global health, drug discovery, food safety, and forensics. Because health care costs are increasing, there is an increasing need to remotely monitor the health condition of patients by point-of-care-testing. The demand for biosensors for detection of biological warfare agents has increased, and research is focused on ways of producing small portable devices that would allow fast, accurate, and on-site detection. In the past decade, the demand for rapid and accurate on-site detection of plant disease diagnosis has increased due to emerging pathogens with resistance to pesticides, increased human mobility, and regulations limiting the application of toxic chemicals to prevent spread of diseases. The portability of biosensors for on-site diagnosis is limited due to various issues, including sample preparation techniques, fluid-handling techniques, the limited lifetime of biological reagents, device packaging, integrating electronics for data collection/analysis, and the requirement of external accessories and power. Many microfluidic, electronic, and biological design strategies, such as handling liquids in biosensors without pumps/valves, the application of droplet-based microfluidics, paper-based microfluidic devices, and wireless networking capabilities for data transmission, are being explored. © 2015 Society for Laboratory Automation and Screening.

Designing electrochemical interfaces with functionalized magnetic nanoparticles and wrapped carbon nanotubes as platforms for the construction of high-performance bienzyme biosensors.

PubMed

Eguílaz, Marcos; Villalonga, Reynaldo; Yáñez-Sedeño, Paloma; Pingarrón, José M

2011-10-15

The design of a novel biosensing electrode surface, combining the advantages of magnetic ferrite nanoparticles (MNPs) functionalized with glutaraldehyde (GA) and poly(diallyldimethylammonium chloride) (PDDA)-coated multiwalled carbon nanotubes (MWCNTs) as platforms for the construction of high-performance multienzyme biosensors, is reported in this work. Before the immobilization of enzymes, GA-MNP/PDDA/MWCNT composites were prepared by wrapping of carboxylated MWCNTs with positively charged PDDA and interaction with GA-functionalized MNPs. The nanoconjugates were characterized by scanning electron microscopy (SEM) and electrochemistry. The electrode platform was used to construct a bienzyme biosensor for the determination of cholesterol, which implied coimmobilization of cholesterol oxidase (ChOx) and peroxidase (HRP) and the use of hydroquinone as redox mediator. Optimization of all variables involved in the preparation and analytical performance of the bienzyme electrode was accomplished. At an applied potential of -0.05 V, a linear calibration graph for cholesterol was obtained in the 0.01-0.95 mM concentration range. The detection limit (0.85 μM), the apparent Michaelis-Menten constant (1.57 mM), the stability of the biosensor, and the calculated activation energy can be advantageously compared with the analytical characteristics of other CNT-based cholesterol biosensors reported in the literature. Analysis of human serum spiked with cholesterol at different concentration levels yielded recoveries between 100% and 103% © 2011 American Chemical Society

Photovoltaic Performance of a Nanowire/Quantum Dot Hybrid Nanostructure Array Solar Cell.

PubMed

Wu, Yao; Yan, Xin; Zhang, Xia; Ren, Xiaomin

2018-02-23

An innovative solar cell based on a nanowire/quantum dot hybrid nanostructure array is designed and analyzed. By growing multilayer InAs quantum dots on the sidewalls of GaAs nanowires, not only the absorption spectrum of GaAs nanowires is extended by quantum dots but also the light absorption of quantum dots is dramatically enhanced due to the light-trapping effect of the nanowire array. By incorporating five layers of InAs quantum dots into a 500-nm high-GaAs nanowire array, the power conversion efficiency enhancement induced by the quantum dots is six times higher than the power conversion efficiency enhancement in thin-film solar cells which contain the same amount of quantum dots, indicating that the nanowire array structure can benefit the photovoltaic performance of quantum dot solar cells.

Photovoltaic Performance of a Nanowire/Quantum Dot Hybrid Nanostructure Array Solar Cell

NASA Astrophysics Data System (ADS)

Wu, Yao; Yan, Xin; Zhang, Xia; Ren, Xiaomin

2018-02-01

An innovative solar cell based on a nanowire/quantum dot hybrid nanostructure array is designed and analyzed. By growing multilayer InAs quantum dots on the sidewalls of GaAs nanowires, not only the absorption spectrum of GaAs nanowires is extended by quantum dots but also the light absorption of quantum dots is dramatically enhanced due to the light-trapping effect of the nanowire array. By incorporating five layers of InAs quantum dots into a 500-nm high-GaAs nanowire array, the power conversion efficiency enhancement induced by the quantum dots is six times higher than the power conversion efficiency enhancement in thin-film solar cells which contain the same amount of quantum dots, indicating that the nanowire array structure can benefit the photovoltaic performance of quantum dot solar cells.

Electrochemical glucose biosensor based on nickel oxide nanoparticle-modified carbon paste electrode.

PubMed

Erdem, Ceren; Zeybek, Derya Koyuncu; Aydoğdu, Gözde; Zeybek, Bülent; Pekyardımcı, Sule; Kılıç, Esma

2014-08-01

In the present work, we designed an amperometric glucose biosensor based on nickel oxide nanoparticles (NiONPs)-modified carbon paste electrode. The biosensor was prepared by incorporation of glucose oxidase and NiONPs into a carbon paste matrix. It showed good analytical performances such as high sensitivity (367 μA mmolL(-1)) and a wide linear response from 1.9×10(-3) mmolL(-1) to 15.0 mmolL(-1) with a limit of detection (0.11 μmolL(-1)). The biosensor was used for the determination of glucose in human serum samples. The results illustrate that NiONPs have enormous potential in the construction of biosensor for determination of glucose.

Topological insulator nanowires and nanowire hetero-junctions

NASA Astrophysics Data System (ADS)

Deng, Haiming; Zhao, Lukas; Wade, Travis; Konczykowski, Marcin; Krusin-Elbaum, Lia

2014-03-01

The existing topological insulator materials (TIs) continue to present a number of challenges to complete understanding of the physics of topological spin-helical Dirac surface conduction channels, owing to a relatively large charge conduction in the bulk. One way to reduce the bulk contribution and to increase surface-to-volume ratio is by nanostructuring. Here we report on the synthesis and characterization of Sb2Te3, Bi2Te3 nanowires and nanotubes and Sb2Te3/Bi2Te3 heterojunctions electrochemically grown in porous anodic aluminum oxide (AAO) membranes with varied (from 50 to 150 nm) pore diameters. Stoichiometric rigid polycrystalline nanowires with controllable cross-sections were obtained using cell voltages in the 30 - 150 mV range. Transport measurements in up to 14 T magnetic fields applied along the nanowires show Aharonov-Bohm (A-B) quantum oscillations with periods corresponding to the nanowire diameters. All nanowires were found to exhibit sharp weak anti-localization (WAL) cusps, a characteristic signature of TIs. In addition to A-B oscillations, new quantization plateaus in magnetoresistance (MR) at low fields (< 0 . 7T) were observed. The analysis of MR as well as I - V characteristics of heterojunctions will be presented. Supported in part by NSF-DMR-1122594, NSF-DMR-1312483-MWN, and DOD-W911NF-13-1-0159.

Nanowire structures and electrical devices

DOEpatents

Bezryadin, Alexey; Remeika, Mikas

2010-07-06

The present invention provides structures and devices comprising conductive segments and conductance constricting segments of a nanowire, such as metallic, superconducting or semiconducting nanowire. The present invention provides structures and devices comprising conductive nanowire segments and conductance constricting nanowire segments having accurately selected phases including crystalline and amorphous states, compositions, morphologies and physical dimensions, including selected cross sectional dimensions, shapes and lengths along the length of a nanowire. Further, the present invention provides methods of processing nanowires capable of patterning a nanowire to form a plurality of conductance constricting segments having selected positions along the length of a nanowire, including conductance constricting segments having reduced cross sectional dimensions and conductance constricting segments comprising one or more insulating materials such as metal oxides.

Nanowire-based thermoelectrics

NASA Astrophysics Data System (ADS)

Ali, Azhar; Chen, Yixi; Vasiraju, Venkata; Vaddiraju, Sreeram

2017-07-01

Research on thermoelectrics has seen a huge resurgence since the early 1990s. The ability of tuning a material’s electrical and thermal transport behavior upon nanostructuring has led to this revival. Nevertheless, thermoelectric performances of nanowires and related materials lag far behind those achieved with thin-film superlattices and quantum dot-based materials. This is despite the fact that nanowires offer many distinct advantages in enhancing the thermoelectric performances of materials. The simplicity of the strategy is the first and foremost advantage. For example, control of the nanowire diameters and their surface roughnesses will aid in enhancing their thermoelectric performances. Another major advantage is the possibility of obtaining high thermoelectric performances using simpler nanowire chemistries (e.g., elemental and binary compound semiconductors), paving the way for the fabrication of thermoelectric modules inexpensively from non-toxic elements. In this context, the topical review provides an overview of the current state of nanowire-based thermoelectrics. It concludes with a discussion of the future vision of nanowire-based thermoelectrics, including the need for developing strategies aimed at the mass production of nanowires and their interface-engineered assembly into devices. This eliminates the need for trial-and-error strategies and complex chemistries for enhancing the thermoelectric performances of materials.

Multiphase separation of copper nanowires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qian, Fang; Lan, Pui Ching; Olson, Tammy

Here, this communication reports a new method to purify copper nanowires with nearly 100% yield from undesired copper nanoparticle side-products formed during batch processes of copper nanowire synthesis. Also, this simple separation method can yield large quantities of long, uniform, high-purity copper nanowires to meet the requirements of nanoelectronics applications as well as provide an avenue for purifying copper nanowires in the industrial scale synthesis of copper nanowires, a key step for commercialization and application of nanowires.

Multiphase separation of copper nanowires

DOE PAGES

Qian, Fang; Lan, Pui Ching; Olson, Tammy; ...

2016-09-01

Here, this communication reports a new method to purify copper nanowires with nearly 100% yield from undesired copper nanoparticle side-products formed during batch processes of copper nanowire synthesis. Also, this simple separation method can yield large quantities of long, uniform, high-purity copper nanowires to meet the requirements of nanoelectronics applications as well as provide an avenue for purifying copper nanowires in the industrial scale synthesis of copper nanowires, a key step for commercialization and application of nanowires.

Programmability of nanowire networks

NASA Astrophysics Data System (ADS)

Bellew, A. T.; Bell, A. P.; McCarthy, E. K.; Fairfield, J. A.; Boland, J. J.

2014-07-01

Electrical connectivity in networks of nanoscale junctions must be better understood if nanowire devices are to be scaled up from single wires to functional material systems. We show that the natural connectivity behaviour found in random nanowire networks presents a new paradigm for creating multi-functional, programmable materials. In devices made from networks of Ni/NiO core-shell nanowires at different length scales, we discover the emergence of distinct behavioural regimes when networks are electrically stressed. We show that a small network, with few nanowire-nanowire junctions, acts as a unipolar resistive switch, demonstrating very high ON/OFF current ratios (>105). However, large networks of nanowires distribute an applied bias across a large number of junctions, and thus respond not by switching but instead by evolving connectivity. We demonstrate that these emergent properties lead to fault-tolerant materials whose resistance may be tuned, and which are capable of adaptively reconfiguring under stress. By combining these two behavioural regimes, we demonstrate that the same nanowire network may be programmed to act both as a metallic interconnect, and a resistive switch device with high ON/OFF ratio. These results enable the fabrication of programmable, multi-functional materials from random nanowire networks.Electrical connectivity in networks of nanoscale junctions must be better understood if nanowire devices are to be scaled up from single wires to functional material systems. We show that the natural connectivity behaviour found in random nanowire networks presents a new paradigm for creating multi-functional, programmable materials. In devices made from networks of Ni/NiO core-shell nanowires at different length scales, we discover the emergence of distinct behavioural regimes when networks are electrically stressed. We show that a small network, with few nanowire-nanowire junctions, acts as a unipolar resistive switch, demonstrating very high ON

Homoepitaxial n-core: p-shell gallium nitride nanowires: HVPE overgrowth on MBE nanowires.

PubMed

Sanders, Aric; Blanchard, Paul; Bertness, Kris; Brubaker, Matthew; Dodson, Christopher; Harvey, Todd; Herrero, Andrew; Rourke, Devin; Schlager, John; Sanford, Norman; Chiaramonti, Ann N; Davydov, Albert; Motayed, Abhishek; Tsvetkov, Denis

2011-11-18

We present the homoepitaxial growth of p-type, magnesium doped gallium nitride shells by use of halide vapor phase epitaxy (HVPE) on n-type gallium nitride nanowires grown by plasma-assisted molecular beam epitaxy (MBE). Scanning electron microscopy shows clear dopant contrast between the core and shell of the nanowire. The growth of magnesium doped nanowire shells shows little or no effect on the lattice parameters of the underlying nanowires, as measured by x-ray diffraction (XRD). Photoluminescence measurements of the nanowires show the appearance of sub-bandgap features in the blue and the ultraviolet, indicating the presence of acceptors. Finally, electrical measurements confirm the presence of electrically active holes in the nanowires.

Rhodium Nanoparticle-mesoporous Silicon Nanowire Nanohybrids for Hydrogen Peroxide Detection with High Selectivity

PubMed Central

Song, Zhiqian; Chang, Hucheng; Zhu, Weiqin; Xu, Chenlong; Feng, Xinjian

2015-01-01

Developing nanostructured electrocatalysts, with low overpotential, high selectivity and activity has fundamental and technical importance in many fields. We report here rhodium nanoparticle and mesoporous silicon nanowire (RhNP@mSiNW) hybrids for hydrogen peroxide (H2O2) detection with high electrocatalytic activity and selectivity. By employing electrodes that loaded with RhNP@mSiNW nanohybrids, interference caused from both many electroactive substances and dissolved oxygen were eliminated by electrochemical assaying at an optimal potential of +75 mV. Furthermore, the electrodes exhibited a high detection sensitivity of 0.53 μA/mM and fast response (< 5 s). This high-performance nanohybrid electrocatalyst has great potential for future practical application in various oxidase-base biosensors. PMID:25588953

A fractal analysis of pathogen detection by biosensors

NASA Astrophysics Data System (ADS)

Doke, Atul M.; Sadana, Ajit

2006-05-01

A fractal analysis is presented for the detection of pathogens such as Franscisela tularensis, and Yersinia pestis (the bacterium that causes plague) using a CANARY (cellular analysis and notification of antigens risks and yields) biosensor (Rider et al., 2003). In general, the binding and dissociation rate coefficients may be adequately described by either a single- or a dual-fractal analysis. An attempt is made to relate the binding rate coefficient to the degree of heterogeneity (fractal dimension value) present on the biosensor surface. Binding and dissociation rate coefficient values obtained are presented. The kinetics aspects along with the affinity values presented are of interest, and should along with the rate coefficients presented for the binding and the dissociation phase be of significant interest in help designing better biosensors for an application area that is bound to gain increasing importance in the future.

Plasmonic Biosensors

PubMed Central

Hill, Ryan T.

2015-01-01

The unique optical properties of plasmon resonant nanostructures enable exploration of nanoscale environments using relatively simple optical characterization techniques. For this reason, the field of plasmonics continues to garner the attention of the biosensing community. Biosensors based on propagating surface plasmon resonances (SPRs) in films are the most well-recognized plasmonic biosensors, but there is great potential for the new, developing technologies to surpass the robustness and popularity of film-based SPR sensing. This review surveys the current plasmonic biosensor landscape with emphasis on the basic operating principles of each plasmonic sensing technique and the practical considerations when developing a sensing platform with the various techniques. The “gold standard” film SPR technique is reviewed briefly, but special emphasis is devoted to the up-and-coming LSPR-based and plasmonically coupled sensor technology. PMID:25377594

Single n+-i-n+ InP nanowires for highly sensitive terahertz detection.

PubMed

Peng, Kun; Parkinson, Patrick; Gao, Qian; Boland, Jessica L; Li, Ziyuan; Wang, Fan; Mokkapati, Sudha; Fu, Lan; Johnston, Michael B; Tan, Hark Hoe; Jagadish, Chennupati

2017-03-24

Developing single-nanowire terahertz (THz) electronics and employing them as sub-wavelength components for highly-integrated THz time-domain spectroscopy (THz-TDS) applications is a promising approach to achieve future low-cost, highly integrable and high-resolution THz tools, which are desirable in many areas spanning from security, industry, environmental monitoring and medical diagnostics to fundamental science. In this work, we present the design and growth of n + -i-n + InP nanowires. The axial doping profile of the n + -i-n + InP nanowires has been calibrated and characterized using combined optical and electrical approaches to achieve nanowire devices with low contact resistances, on which the highly-sensitive InP single-nanowire photoconductive THz detectors have been demonstrated. While the n + -i-n + InP nanowire detector has a only pA-level response current, it has a 2.5 times improved signal-to-noise ratio compared with the undoped InP nanowire detector and is comparable to traditional bulk THz detectors. This performance indicates a promising path to nanowire-based THz electronics for future commercial applications.

Enzyme Biosensors for Biomedical Applications: Strategies for Safeguarding Analytical Performances in Biological Fluids

PubMed Central

Rocchitta, Gaia; Spanu, Angela; Babudieri, Sergio; Latte, Gavinella; Madeddu, Giordano; Galleri, Grazia; Nuvoli, Susanna; Bagella, Paola; Demartis, Maria Ilaria; Fiore, Vito; Manetti, Roberto; Serra, Pier Andrea

2016-01-01

Enzyme-based chemical biosensors are based on biological recognition. In order to operate, the enzymes must be available to catalyze a specific biochemical reaction and be stable under the normal operating conditions of the biosensor. Design of biosensors is based on knowledge about the target analyte, as well as the complexity of the matrix in which the analyte has to be quantified. This article reviews the problems resulting from the interaction of enzyme-based amperometric biosensors with complex biological matrices containing the target analyte(s). One of the most challenging disadvantages of amperometric enzyme-based biosensor detection is signal reduction from fouling agents and interference from chemicals present in the sample matrix. This article, therefore, investigates the principles of functioning of enzymatic biosensors, their analytical performance over time and the strategies used to optimize their performance. Moreover, the composition of biological fluids as a function of their interaction with biosensing will be presented. PMID:27249001

High speed superconducting nanowire single-photon detector with nine interleaved nanowires

NASA Astrophysics Data System (ADS)

Huang, Jia; Zhang, Weijun; You, Lixing; Zhang, Chengjun; Lv, Chaolin; Wang, Yong; Liu, Xiaoyu; Li, Hao; Wang, Zhen

2018-07-01

Count rate (CR) is one of the key parameters of superconducting nanowire single-photon detectors (SNSPDs). The practical SNSPDs usually have a CR of a few MHz to a few tens of MHz owing to the large kinetic inductance originating from the long nanowire, which is necessary for effectively coupling the photons. A feasible approach to decrease the kinetic inductance and consequently increase the detection speed is to replace a long single nanowire with multiple individual nanowires in an array. In this study, we report an SNSPD of nine interleaved nanowires with 70% system detection efficiency (SDE) and 200 Hz dark count rate at the low-photon-flux limit of 1550 nm. Owing to the small dead time (<6 ns) of each nanowire, the SNSPD achieved a maximum CR of 0.93 GHz at a photon flux of 1.26 × 1010 photons s‑1 with an SDE of ∼7.4%, and a CR of 200 MHz with an SDE of over 50%. Furthermore, a photon number resolvability of up to nine photons was also demonstrated.

Capacitive Biosensors and Molecularly Imprinted Electrodes.

PubMed

Ertürk, Gizem; Mattiasson, Bo

2017-02-17

Capacitive biosensors belong to the group of affinity biosensors that operate by registering direct binding between the sensor surface and the target molecule. This type of biosensors measures the changes in dielectric properties and/or thickness of the dielectric layer at the electrolyte/electrode interface. Capacitive biosensors have so far been successfully used for detection of proteins, nucleotides, heavy metals, saccharides, small organic molecules and microbial cells. In recent years, the microcontact imprinting method has been used to create very sensitive and selective biorecognition cavities on surfaces of capacitive electrodes. This chapter summarizes the principle and different applications of capacitive biosensors with an emphasis on microcontact imprinting method with its recent capacitive biosensor applications.

Auto-FPFA: An Automated Microscope for Characterizing Genetically Encoded Biosensors.

PubMed

Nguyen, Tuan A; Puhl, Henry L; Pham, An K; Vogel, Steven S

2018-05-09

Genetically encoded biosensors function by linking structural change in a protein construct, typically tagged with one or more fluorescent proteins, to changes in a biological parameter of interest (such as calcium concentration, pH, phosphorylation-state, etc.). Typically, the structural change triggered by alterations in the bio-parameter is monitored as a change in either fluorescent intensity, or lifetime. Potentially, other photo-physical properties of fluorophores, such as fluorescence anisotropy, molecular brightness, concentration, and lateral and/or rotational diffusion could also be used. Furthermore, while it is likely that multiple photo-physical attributes of a biosensor might be altered as a function of the bio-parameter, standard measurements monitor only a single photo-physical trait. This limits how biosensors are designed, as well as the accuracy and interpretation of biosensor measurements. Here we describe the design and construction of an automated multimodal-microscope. This system can autonomously analyze 96 samples in a micro-titer dish and for each sample simultaneously measure intensity (photon count), fluorescence lifetime, time-resolved anisotropy, molecular brightness, lateral diffusion time, and concentration. We characterize the accuracy and precision of this instrument, and then demonstrate its utility by characterizing three types of genetically encoded calcium sensors as well as a negative control.

Precise Placement of Metallic Nanowires on a Substrate by Localized Electric Fields and Inter-Nanowire Electrostatic Interaction

PubMed Central

2017-01-01

Placing nanowires at the predetermined locations on a substrate represents one of the significant hurdles to be tackled for realization of heterogeneous nanowire systems. Here, we demonstrate spatially-controlled assembly of a single nanowire at the photolithographically recessed region at the electrode gap with high integration yield (~90%). Two popular routes, such as protruding electrode tips and recessed wells, for spatially-controlled nanowire alignment, are compared to investigate long-range dielectrophoretic nanowire attraction and short-range nanowire-nanowire electrostatic interaction for determining the final alignment of attracted nanowires. Furthermore, the post-assembly process has been developed and tested to make a robust electrical contact to the assembled nanowires, which removes any misaligned ones and connects the nanowires to the underlying electrodes of circuit. PMID:29048363

Biomolecular logic systems: applications to biosensors and bioactuators

NASA Astrophysics Data System (ADS)

Katz, Evgeny

2014-05-01

The paper presents an overview of recent advances in biosensors and bioactuators based on the biocomputing concept. Novel biosensors digitally process multiple biochemical signals through Boolean logic networks of coupled biomolecular reactions and produce output in the form of YES/NO response. Compared to traditional single-analyte sensing devices, biocomputing approach enables a high-fidelity multi-analyte biosensing, particularly beneficial for biomedical applications. Multi-signal digital biosensors thus promise advances in rapid diagnosis and treatment of diseases by processing complex patterns of physiological biomarkers. Specifically, they can provide timely detection and alert to medical emergencies, along with an immediate therapeutic intervention. Application of the biocomputing concept has been successfully demonstrated for systems performing logic analysis of biomarkers corresponding to different injuries, particularly exemplified for liver injury. Wide-ranging applications of multi-analyte digital biosensors in medicine, environmental monitoring and homeland security are anticipated. "Smart" bioactuators, for example for signal-triggered drug release, were designed by interfacing switchable electrodes and biocomputing systems. Integration of novel biosensing and bioactuating systems with the biomolecular information processing systems keeps promise for further scientific advances and numerous practical applications.

Label-free optical biosensors based on aptamer-functionalized porous silicon scaffolds.

PubMed

Urmann, Katharina; Walter, Johanna-Gabriela; Scheper, Thomas; Segal, Ester

2015-02-03

A proof-of-concept for a label-free and reagentless optical biosensing platform based on nanostructured porous silicon (PSi) and aptamers is presented in this work. Aptamers are oligonucleotides (single-stranded DNA or RNA) that can bind their targets with high affinity and specificity, making them excellent recognition elements for biosensor design. Here we describe the fabrication and characterization of aptamer-conjugated PSi biosensors, where a previously characterized his-tag binding aptamer (6H7) is used as model system. Exposure of the aptamer-functionalized PSi to the target proteins as well as to complex fluids (i.e., bacteria lysates containing target proteins) results in robust and well-defined changes in the PSi optical interference spectrum, ascribed to specific aptamer-protein binding events occurring within the nanoscale pores, monitored in real time. The biosensors show exceptional stability and can be easily regenerated by a short rinsing step for multiple biosensing analyses. This proof-of-concept study demonstrates the possibility of designing highly stable and specific label-free optical PSi biosensors, employing aptamers as capture probes, holding immense potential for application in detection of a broad range of targets, in a simple yet reliable manner.

Nanomaterials-based enzyme electrochemical biosensors operating through inhibition for biosensing applications.

PubMed

Kurbanoglu, Sevinc; Ozkan, Sibel A; Merkoçi, Arben

2017-03-15

In recent years great progress has been made in applying nanomaterials to design novel biosensors. Use of nanomaterials offers to biosensing platforms exceptional optical, electronic and magnetic properties. Nanomaterials can increase the surface of the transducing area of the sensors that in turn bring an increase in catalytic behaviors. They have large surface-to-volume ratio, controlled morphology and structure that also favor miniaturization, an interesting advantage when the sample volume is a critical issue. Biosensors have great potential for achieving detect-to-protect devices: devices that can be used in detections of pollutants and other treating compounds/analytes (drugs) protecting citizens' life. After a long term focused scientific and financial efforts/supports biosensors are expected now to fulfill their promise such as being able to perform sampling and analysis of complex samples with interest for clinical or environment fields. Among all types of biosensors, enzymatic biosensors, the most explored biosensing devices, have an interesting property, the inherent inhibition phenomena given the enzyme-substrate complex formation. The exploration of such phenomena is making remarkably important their application as research and applied tools in diagnostics. Different inhibition biosensor systems based on nanomaterials modification has been proposed and applied. The role of nanomaterials in inhibition-based biosensors for the analyses of different groups of drugs as well as contaminants such as pesticides, phenolic compounds and others, are discussed in this review. This deep analysis of inhibition-based biosensors that employ nanomaterials will serve researchers as a guideline for further improvements and approaching of these devices to real sample applications so as to reach society needs and such biosensor market demands. Copyright © 2016 Elsevier B.V. All rights reserved.

Self-assembled phase-change nanowire for nonvolatile electronic memory

NASA Astrophysics Data System (ADS)

Jung, Yeonwoong

One of the most important subjects in nanosciences is to identify and exploit the relationship between size and structural/physical properties of materials and to explore novel material properties at a small-length scale. Scale-down of materials is not only advantageous in realizing miniaturized devices but nanometer-sized materials often exhibit intriguing physical/chemical properties that greatly differ from their bulk counterparts. This dissertation studies self-assembled phase-change nanowires for future nonvolatile electronic memories, mainly focusing on their size-dependent memory switching properties. Owing to the one-dimensional, unique geometry coupled with the small and tunable sizes, bottom-designed nanowires offer great opportunities in terms for both fundamental science and practical engineering perspectives, which would be difficult to realize in conventional top-down based approaches. We synthesized chalcogenide phase-change nanowires of different compositions and sizes, and studied their electronic memory switching owing to the structural change between crystalline and amorphous phases. In particular, we investigated nanowire size-dependent memory switching parameters, including writing current, power consumption, and data retention times, as well as studying composition-dependent electronic properties. The observed size and composition-dependent switching and recrystallization kinetics are explained based on the heat transport model and heterogeneous nucleation theories, which help to design phase-change materials with better properties. Moreover, we configured unconventional heterostructured phase-change nanowire memories and studied their multiple memory states in single nanowire devices. Finally, by combining in-situ/ex-situ electron microscopy techniques and electrical measurements, we characterized the structural states involved in electrically-driven phase-change in order to understand the atomistic mechanism that governs the electronic

Nanowire Thermoelectric Devices

NASA Technical Reports Server (NTRS)

Borshchevsky, Alexander; Fleurial, Jean-Pierre; Herman, Jennifer; Ryan, Margaret

2005-01-01

Nanowire thermoelectric devices, now under development, are intended to take miniaturization a step beyond the prior state of the art to exploit the potential advantages afforded by shrinking some device features to approximately molecular dimensions (of the order of 10 nm). The development of nanowire-based thermoelectric devices could lead to novel power-generating, cooling, and sensing devices that operate at relatively low currents and high voltages. Recent work on the theory of thermoelectric devices has led to the expectation that the performance of such a device could be enhanced if the diameter of the wires could be reduced to a point where quantum confinement effects increase charge-carrier mobility (thereby increasing the Seebeck coefficient) and reduce thermal conductivity. In addition, even in the absence of these effects, the large aspect ratios (length of the order of tens of microns diameter of the order of tens of nanometers) of nanowires would be conducive to the maintenance of large temperature differences at small heat fluxes. The predicted net effect of reducing diameters to the order of tens of nanometers would be to increase its efficiency by a factor of .3. Nanowires made of thermoelectric materials and devices that comprise arrays of such nanowires can be fabricated by electrochemical growth of the thermoelectric materials in templates that contain suitably dimensioned pores (10 to 100 nm in diameter and 1 to 100 microns long). The nanowires can then be contacted in bundles to form devices that look similar to conventional thermoelectric devices, except that a production version may contain nearly a billion elements (wires) per square centimeter, instead of fewer than a hundred as in a conventional bulk thermoelectric device or fewer than 100,000 as in a microdevice. It is not yet possible to form contacts with individual nanowires. Therefore, in fabricating a nanowire thermoelectric device, one forms contacts on nanowires in bundles of the

Plasmonic biosensors.

PubMed

Hill, Ryan T

2015-01-01

The unique optical properties of plasmon resonant nanostructures enable exploration of nanoscale environments using relatively simple optical characterization techniques. For this reason, the field of plasmonics continues to garner the attention of the biosensing community. Biosensors based on propagating surface plasmon resonances (SPRs) in films are the most well-recognized plasmonic biosensors, but there is great potential for the new, developing technologies to surpass the robustness and popularity of film-based SPR sensing. This review surveys the current plasmonic biosensor landscape with emphasis on the basic operating principles of each plasmonic sensing technique and the practical considerations when developing a sensing platform with the various techniques. The 'gold standard' film SPR technique is reviewed briefly, but special emphasis is devoted to the up-and-coming localized surface plasmon resonance and plasmonically coupled sensor technology. © 2014 Wiley Periodicals, Inc.

Biosensors based on enzyme field-effect transistors for determination of some substrates and inhibitors.

PubMed

Dzyadevych, Sergei V; Soldatkin, Alexey P; Korpan, Yaroslav I; Arkhypova, Valentyna N; El'skaya, Anna V; Chovelon, Jean-Marc; Martelet, Claude; Jaffrezic-Renault, Nicole

2003-10-01

This paper is a review of the authors' publications concerning the development of biosensors based on enzyme field-effect transistors (ENFETs) for direct substrates or inhibitors analysis. Such biosensors were designed by using immobilised enzymes and ion-selective field-effect transistors (ISFETs). Highly specific, sensitive, simple, fast and cheap determination of different substances renders them as promising tools in medicine, biotechnology, environmental control, agriculture and the food industry. The biosensors based on ENFETs and direct enzyme analysis for determination of concentrations of different substrates (glucose, urea, penicillin, formaldehyde, creatinine, etc.) have been developed and their laboratory prototypes were fabricated. Improvement of the analytical characteristics of such biosensors may be achieved by using a differential mode of measurement, working solutions with different buffer concentrations and specific agents, negatively or positively charged additional membranes, or genetically modified enzymes. These approaches allow one to decrease the effect of the buffer capacity influence on the sensor response in an aim to increase the sensitivity of the biosensors and to extend their dynamic ranges. Biosensors for the determination of concentrations of different toxic substances (organophosphorous pesticides, heavy metal ions, hypochlorite, glycoalkaloids, etc.) were designed on the basis of reversible and/or irreversible enzyme inhibition effect(s). The conception of an enzymatic multibiosensor for the determination of different toxic substances based on the enzyme inhibition effect is also described. We will discuss the respective advantages and disadvantages of biosensors based on the ENFETs developed and also demonstrate their practical application.

Lithographically fabricated gold nanowire waveguides for plasmonic routers and logic gates.

PubMed

Gao, Long; Chen, Li; Wei, Hong; Xu, Hongxing

2018-06-14

Fabricating plasmonic nanowire waveguides and circuits by lithographic fabrication methods is highly desired for nanophotonic circuitry applications. Here we report an approach for fabricating metal nanowire networks by using electron beam lithography and metal film deposition techniques. The gold nanowire structures are fabricated on quartz substrates without using any adhesion layer but coated with a thin layer of Al2O3 film for immobilization. The thermal annealing during the Al2O3 deposition process decreases the surface plasmon loss. In a Y-shaped gold nanowire network, the surface plasmons can be routed to different branches by controlling the polarization of the excitation light, and the routing behavior is dependent on the length of the main nanowire. Simulated electric field distributions show that the zigzag distribution of the electric field in the nanowire network determines the surface plasmon routing. By using two laser beams to excite surface plasmons in a Y-shaped nanowire network, the output intensity can be modulated by the interference of surface plasmons, which can be used to design Boolean logic gates. We experimentally demonstrate that AND, OR, XOR and NOT gates can be realized in three-terminal nanowire networks, and NAND, NOR and XNOR gates can be realized in four-terminal nanowire networks. This work takes a step toward the fabrication of on-chip integrated plasmonic circuits.

Role of biomolecular logic systems in biosensors and bioactuators

NASA Astrophysics Data System (ADS)

Mailloux, Shay; Katz, Evgeny

2014-09-01

An overview of recent advances in biosensors and bioactuators based on biocomputing systems is presented. Biosensors digitally process multiple biochemical signals through Boolean logic networks of coupled biomolecular reactions and produce an output in the form of a YES/NO response. Compared to traditional single-analyte sensing devices, the biocomputing approach enables high-fidelity multianalyte biosensing, which is particularly beneficial for biomedical applications. Multisignal digital biosensors thus promise advances in rapid diagnosis and treatment of diseases by processing complex patterns of physiological biomarkers. Specifically, they can provide timely detection and alert medical personnel of medical emergencies together with immediate therapeutic intervention. Application of the biocomputing concept has been successfully demonstrated for systems performing logic analysis of biomarkers corresponding to different injuries, particularly as exemplified for liver injury. Wide-ranging applications of multianalyte digital biosensors in medicine, environmental monitoring, and homeland security are anticipated. "Smart" bioactuators, for signal-triggered drug release, for example, were designed by interfacing switchable electrodes with biocomputing systems. Integration of biosensing and bioactuating systems with biomolecular information processing systems advances the potential for further scientific innovations and various practical applications.

Introduction to biosensors

PubMed Central

Bhalla, Nikhil; Jolly, Pawan; Formisano, Nello

2016-01-01

Biosensors are nowadays ubiquitous in biomedical diagnosis as well as a wide range of other areas such as point-of-care monitoring of treatment and disease progression, environmental monitoring, food control, drug discovery, forensics and biomedical research. A wide range of techniques can be used for the development of biosensors. Their coupling with high-affinity biomolecules allows the sensitive and selective detection of a range of analytes. We give a general introduction to biosensors and biosensing technologies, including a brief historical overview, introducing key developments in the field and illustrating the breadth of biomolecular sensing strategies and the expansion of nanotechnological approaches that are now available. PMID:27365030

Photonic crystal fiber-based plasmonic biosensor with external sensing approach

NASA Astrophysics Data System (ADS)

Rifat, Ahmmed A.; Hasan, Md. Rabiul; Ahmed, Rajib; Butt, Haider

2018-01-01

We propose a simple photonic crystal fiber (PCF) biosensor based on the surface plasmon resonance effect. The sensing properties are characterized using the finite element method. Chemically stable gold material is deposited on the outer surface of the PCF to realize the practical sensing approach. The performance of the modeled biosensor is investigated in terms of wavelength sensitivity, amplitude sensitivity, sensor resolution, and linearity of the resonant wavelength with the variation of structural parameters. In the sensing range of 1.33 to 1.37, maximum sensitivities of 4000 nm/RIU and 478 are achieved with the high sensor resolutions of 2.5×10-5 and 2.1×10-5 RIU using wavelength and amplitude interrogation methods, respectively. The designed biosensor will reduce fabrication complexity due to its simple and realistic hexagonal lattice structure. It is anticipated that the proposed biosensor may find possible applications for unknown biological and biochemical analyte detections with a high degree of accuracy.

Microbial fuel cell-based biosensor for toxic carbon monoxide monitoring.

PubMed

Zhou, Shaofeng; Huang, Shaobin; Li, Yi; Zhao, Nannan; Li, Han; Angelidaki, Irini; Zhang, Yifeng

2018-08-15

This study presents an innovative microbial fuel cell-based biosensor for carbon monoxide (CO) monitoring. The hypothesis for the function of the biosensor is that CO inhibits bacterial activity in the anode and thereby reduces electricity production. A mature electrochemically active biofilm on the anode was exposed to CO gas at varied concentrations. A proportional linear relationship (R 2 = 0.987) between CO concentration and voltage drop (0.8 to 24 mV) in the range of 10% and 70% of CO concentration was observed. Notably, no further decrease of voltage output was observed by with further increasing CO concentration over 70%. Besides, the response time of the biosensor was 1 h. The compact design and simple operation of the biosensor makes it easy to be integrated in existing CO-based industrial facilities either as a forewarning sensor for CO toxicity or even as an individual on-line monitoring device. Copyright © 2018 Elsevier B.V. All rights reserved.

Silicon nanowires: where mechanics and optics meet at the nanoscale.

PubMed

Ramos, Daniel; Gil-Santos, Eduardo; Malvar, Oscar; Llorens, Jose M; Pini, Valerio; San Paulo, Alvaro; Calleja, Montserrat; Tamayo, Javier

2013-12-06

Mechanical transducers based on nanowires promise revolutionary advances in biological sensing and force microscopy/spectroscopy. A crucial step is the development of simple and non-invasive techniques able to detect displacements with subpicometer sensitivity per unit bandwidth. Here, we design suspended tapered silicon nanowires supporting a range of optical resonances that confine and efficiently scatter light in the visible range. Then, we develop an optical method for efficiently coupling the evanescent field to the regular interference pattern generated by an incoming laser beam and the reflected beam from the substrate underneath the nanowire. This optomechanical coupling is here applied to measure the displacement of 50 nm wide nanowires with sensitivity on the verge of 1 fm/Hz(1/2) at room temperature with a simple laser interferometry set-up. This method opens the door to the measurement of the Brownian motion of ultrashort nanowires for the detection of single biomolecular recognition events in liquids, and single molecule spectroscopy in vacuum.

Sensitive electrochemical nonenzymatic glucose sensing based on anodized CuO nanowires on three-dimensional porous copper foam

NASA Astrophysics Data System (ADS)

Li, Zhenzhen; Chen, Yan; Xin, Yanmei; Zhang, Zhonghai

2015-11-01

In this work, we proposed to utilize three-dimensional porous copper foam (CF) as conductive substrate and precursor of in-situ growth CuO nanowires (NWs) for fabricating electrochemical nonenzymatic glucose sensors. The CF supplied high surface area due to its unique three-dimensional porous foam structure, and thus resulted in high sensitivity for glucose detection. The CuO NWs/CF based nonenzymatic sensors presented reliable selectivity, good repeatability, reproducibility, and stability. In addition, the CuO NWs/CF based nonenzymatic sensors have been employed for practical applications, and the glucose concentration in human serum was measured to be 4.96 ± 0.06 mM, agreed well with the value measured from the commercial available glucose sensor in hospital, and the glucose concentration in saliva was also estimated to be 0.91 ± 0.04 mM, which indicated that the CuO NWs/CF owned the possibility for noninvasive glucose detection. The rational design of CuO NWs/CF provided an efficient strategy for fabricating of electrochemical nonenzymatic biosensors.

Sensitive electrochemical nonenzymatic glucose sensing based on anodized CuO nanowires on three-dimensional porous copper foam

PubMed Central

Li, Zhenzhen; Chen, Yan; Xin, Yanmei; Zhang, Zhonghai

2015-01-01

In this work, we proposed to utilize three-dimensional porous copper foam (CF) as conductive substrate and precursor of in-situ growth CuO nanowires (NWs) for fabricating electrochemical nonenzymatic glucose sensors. The CF supplied high surface area due to its unique three-dimensional porous foam structure, and thus resulted in high sensitivity for glucose detection. The CuO NWs/CF based nonenzymatic sensors presented reliable selectivity, good repeatability, reproducibility, and stability. In addition, the CuO NWs/CF based nonenzymatic sensors have been employed for practical applications, and the glucose concentration in human serum was measured to be 4.96 ± 0.06 mM, agreed well with the value measured from the commercial available glucose sensor in hospital, and the glucose concentration in saliva was also estimated to be 0.91 ± 0.04 mM, which indicated that the CuO NWs/CF owned the possibility for noninvasive glucose detection. The rational design of CuO NWs/CF provided an efficient strategy for fabricating of electrochemical nonenzymatic biosensors. PMID:26522446

Recent advances in biosensor development for the detection of cancer biomarkers.

PubMed

Jayanthi, V S P K Sankara Aditya; Das, Asim Bikas; Saxena, Urmila

2017-05-15

Cancer is the second largest disease throughout the world with an increasing mortality rate over the past few years. The patient's survival rate is uncertain due to the limitations of cancer diagnosis and therapy. Early diagnosis of cancer is decisive for its successful treatment. A biomarker-based cancer diagnosis may significantly improve the early diagnosis and subsequent treatment. Biosensors play a crucial role in the detection of biomarkers as they are easy to use, portable, and can do analysis in real time. This review describes various biosensors designed for detecting nucleic acid and protein-based cancer biomarkers for cancer diagnosis. It mainly lays emphasis on different approaches to use electrochemical, optical, and mass-based transduction systems in cancer biomarker detection. It also highlights the analytical performances of various biosensor designs concerning cancer biomarkers in detail. Copyright © 2016 Elsevier B.V. All rights reserved.

Gold nanoparticles and polyethylene glycols functionalized conducting polyaniline nanowires for ultrasensitive and low fouling immunosensing of alpha-fetoprotein.

PubMed

Hui, Ni; Sun, Xiaotian; Song, Zhiling; Niu, Shuyan; Luo, Xiliang

2016-12-15

An ultrasensitive biosensor for alpha-fetoprotein was developed based on electrochemically synthesized polyaniline (PANI) nanowires, which were functionalized with gold nanoparticles (AuNPs) and polyethylene glycols (PEG). The prepared PEG/AuNPs/PANI composite, combining the electrical conductivity of the AuNPs/PANI with the robust antifouling ability of PEG, offered an ideal substrate for the development of low fouling electrochemical biosensors. Alpha-fetoprotein (AFP), a well-known hepatocellular carcinoma biomarker, was used as a model analyte, and its antibody was immobilized on the PEG/AuNPs/PANI for the construction of the AFP immunosensor. Using the redox current of PANI as the sensing signal, in addition to the good biocompatibility of PEG/AuNPs and the anti-biofouling property of PEG, the developed immunosensor showed improved biosensing performances, such as wide linear range and ultralow detection limit (0.007pgmL(-1)). More importantly, it is label-free, reagentless and low fouling, making it capable of assaying AFP in real serum samples without suffering from significant interference or biofouling. Copyright © 2016 Elsevier B.V. All rights reserved.

Nanomaterials-based biosensors for detection of microorganisms and microbial toxins.

PubMed

Sutarlie, Laura; Ow, Sian Yang; Su, Xiaodi

2017-04-01

Detection of microorganisms and microbial toxins is important for health and safety. Due to their unique physical and chemical properties, nanomaterials have been extensively used to develop biosensors for rapid detection of microorganisms with microbial cells and toxins as target analytes. In this paper, the design principles of nanomaterials-based biosensors for four selected analyte categories (bacteria cells, toxins, mycotoxins, and protozoa cells), closely associated with the target analytes' properties is reviewed. Five signal transducing methods that are less equipment intensive (colorimetric, fluorimetric, surface enhanced Raman scattering, electrochemical, and magnetic relaxometry methods) is described and compared for their sensory performance (in term oflimit of detection, dynamic range, and response time) for all analyte categories. In the end, the suitability of these five sensing principles for on-site or field applications is discussed. With a comprehensive coverage of nanomaterials, design principles, sensing principles, and assessment on the sensory performance and suitability for on-site application, this review offers valuable insight and perspective for designing suitable nanomaterials-based microorganism biosensors for a given application. Copyright © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optoelectronics: Continuously Spatial-Wavelength-Tunable Nanowire Lasers on a Single Chip

DTIC Science & Technology

2014-01-28

journals (N/A for none) 1. P. L. Nichols, Z. Liu, L. Yin, and C. Z. Ning, CdxPb1- xS Alloy Nanowires and Heterostructures with Simultaneous Emission in Mid...multiple-bandgap solar cells using spatially composition-graded CdxPb1- xS nanowires on a single substrate: a design study, Optics Express (07 2011...Quaternary ZnCdSSe Alloy Nanowires with Tunable Light Emission Between 350 nm and 710 nm on a Single Substrate, (11 2009) C.Z. Ning, A.L. Pan, and

CuO nanowire/microflower/nanowire modified Cu electrode with enhanced electrochemical performance for non-enzymatic glucose sensing.

PubMed

Li, Changli; Yamahara, Hiroyasu; Lee, Yaerim; Tabata, Hitoshi; Delaunay, Jean-Jacques

2015-07-31

CuO nanowire/microflower structure on Cu foil is synthesized by annealing a Cu(OH)2 nanowire/CuO microflower structure at 250 °C in air. The nanowire/microflower structure with its large surface area leads to an efficient catalysis and charge transfer in glucose detection, achieving a high sensitivity of 1943 μA mM(-1) cm(-2), a wide linear range up to 4 mM and a low detection limit of 4 μM for amperometric glucose sensing in alkaline solution. With a second consecutive growth of CuO nanowires on the microflowers, the sensitivity of the obtained CuO nanowire/microflower/nanowire structure further increases to 2424 μA mM(-1) cm(-2), benefiting from an increased number of electrochemically active sites. The enhanced electrocatalytic performance of the CuO nanowire/microflower/nanowire electrode compared to the CuO nanowire/microflower electrode, CuO nanowire electrode and CuxO film electrode provides evidence for the significant role of available surface area for electrocatalysis. The rational combination of CuO nanowire and microflower nanostructures into a nanowire supporting microflower branching nanowires structure makes it a promising composite nanostructure for use in CuO based electrochemical sensors with promising analytical properties.

Biosensors for hepatitis B virus detection.

PubMed

Yao, Chun-Yan; Fu, Wei-Ling

2014-09-21

A biosensor is an analytical device used for the detection of analytes, which combines a biological component with a physicochemical detector. Recently, an increasing number of biosensors have been used in clinical research, for example, the blood glucose biosensor. This review focuses on the current state of biosensor research with respect to efficient, specific and rapid detection of hepatitis B virus (HBV). The biosensors developed based on different techniques, including optical methods (e.g., surface plasmon resonance), acoustic wave technologies (e.g., quartz crystal microbalance), electrochemistry (amperometry, voltammetry and impedance) and novel nanotechnology, are also discussed.

Graphene-based biosensors.

PubMed

Szunerits, Sabine; Boukherroub, Rabah

2018-06-06

Reliable data obtained from analysis of DNA, proteins, bacteria and other disease-related molecules or organisms in biological samples have become a fundamental and crucial part of human health diagnostics and therapy. The development of non-invasive tests that are rapid, sensitive, specific and simple would allow patient discomfort to be prevented, delays in diagnosis to be avoided and the status of a disease to be followed up. Bioanalysis is thus a progressive discipline for which the future holds many exciting opportunities. The use of biosensors for the early diagnosis of diseases has become widely accepted as a point-of-care diagnosis with appropriate specificity in a short time. To allow a reliable diagnosis of a disease at an early stage, highly sensitive biosensors are required as the corresponding biomarkers are generally expressed at very low concentrations. In the past 50 years, various biosensors have been researched and developed encompassing a wide range of applications. This contrasts the limited number of commercially available biosensors. When it comes to sensing of biomarkers with the required picomolar (pM) sensitivity for real-time sensing of biological samples, only a handful of sensing systems have been proposed, and these are often rather complex and costly. Lately, graphene-based materials have been considered as superior over other nanomaterials for the development of sensitive biosensors. The advantages of graphene-based sensor interfaces are numerous, including enhanced surface loading of the desired ligand due to the high surface-to-volume ratio, excellent conductivity and a small band gap that is beneficial for sensitive electrical and electrochemical read-outs, as well as tunable optical properties for optical read-outs such as fluorescence and plasmonics. In this paper, we review the advances made in recent years on graphene-based biosensors in the field of medical diagnosis.

Functional design of electrolytic biosensor

NASA Astrophysics Data System (ADS)

Gamage Preethichandra, D. M.; Mala Ekanayake, E. M. I.; Onoda, M.

2017-11-01

A novel amperometric biosensbased on conjugated polypyrrole (PPy) deposited on a Pt modified ITO (indium tin oxide) conductive glass substrate and their performances are described. We have presented a method of developing a highly sensitive and low-cost nano-biosensor for blood glucose measurements. The fabrication method proposed decreases the cost of production significantly as the amount of noble metals used is minimized. A nano-corrugated PPy substrate was developed through pulsed electrochemical deposition. The sensitivity achieved was 325 mA/(Mcm2) and the linear range of the developed sensor was 50-60 mmol/l. Then the application of the electrophoresis helps the glucose oxidase (GOx) on the PPy substrate. The main reason behind this high enzyme loading is the high electric field applied across the sensor surface (working electrode) and the counter electrode where that pushes the nano-scale enzyme particles floating in the phosphate buffer solution towards the substrate. The novel technique used has provided an extremely high sensitivities and very high linear ranges for enzyme (GOx) and therefore can be concluded that this is a very good technique to load enzyme onto the conducting polymer substrates.

Porous Silicon Nanowires

PubMed Central

Qu, Yongquan; Zhou, Hailong; Duan, Xiangfeng

2011-01-01

In this minreview, we summarize recent progress in the synthesis, properties and applications of a new type of one-dimensional nanostructures — single crystalline porous silicon nanowires. The growth of porous silicon nanowires starting from both p- and n-type Si wafers with a variety of dopant concentrations can be achieved through either one-step or two-step reactions. The mechanistic studies indicate the dopant concentration of Si wafers, oxidizer concentration, etching time and temperature can affect the morphology of the as-etched silicon nanowires. The porous silicon nanowires are both optically and electronically active and have been explored for potential applications in diverse areas including photocatalysis, lithium ion battery, gas sensor and drug delivery. PMID:21869999

Self-Assembled N-Heterocyclic Carbene-Based Carboxymethylated Dextran Monolayers on Gold as a Tunable Platform for Designing Affinity-Capture Biosensor Surfaces.

PubMed

Li, Zhijun; Munro, Kim; Narouz, Mina R; Lau, Andrew; Hao, Hongxia; Crudden, Cathleen M; Horton, J Hugh

2018-05-30

Sensor surfaces play a predominant role in the development of optical biosensor technologies for the analysis of biomolecular interactions. Thiol-based self-assembled monolayers (SAMs) on gold have been widely used as linker layers for sensor surfaces. However, the degradation of the thiol-gold bond can limit the performance and durability of such surfaces, directly impacting their performance and cost-effectiveness. To this end, a new family of materials based on N-heterocyclic carbenes (NHCs) has emerged as an alternative for surface modification, capable of self-assembling onto a gold surface with higher affinity and superior stability as compared to the thiol-based systems. Here we demonstrate three applications of NHC SAMs supporting a dextran layer as a tunable platform for developing various affinity-capture biosensor surfaces. We describe the development and testing of NHC-based dextran biosensor surfaces modified with each of streptavidin, nitrilotriacetic acid, and recombinant Protein A. These affinity-capture sensor surfaces enable oriented binding of ligands for optimal performance in biomolecular assays. Together, the intrinsic high stability and flexible design of the NHC biosensing platforms show great promise and open up exciting possibilities for future biosensing applications.

Graphene-based field-effect transistor biosensors

DOEpatents

Chen; , Junhong; Mao, Shun; Lu, Ganhua

2017-06-14

The disclosure provides a field-effect transistor (FET)-based biosensor and uses thereof. In particular, to FET-based biosensors using thermally reduced graphene-based sheets as a conducting channel decorated with nanoparticle-biomolecule conjugates. The present disclosure also relates to FET-based biosensors using metal nitride/graphene hybrid sheets. The disclosure provides a method for detecting a target biomolecule in a sample using the FET-based biosensor described herein.

Electrochemical DNA biosensor based on grafting-to mode of terminal deoxynucleoside transferase-mediated extension.

PubMed

Chen, Jinyuan; Liu, Zhoujie; Peng, Huaping; Zheng, Yanjie; Lin, Zhen; Liu, Ailin; Chen, Wei; Lin, Xinhua

2017-12-15

Previously reported electrochemical DNA biosensors based on in-situ polymerization approach reveal that terminal deoxynucleoside transferase (TdTase) has good amplifying performance and promising application in the design of electrochemical DNA biosensor. However, this method, in which the background is significantly affected by the amount of TdTase, suffers from being easy to produce false positive result and poor stability. Herein, we firstly present a novel electrochemical DNA biosensor based on grafting-to mode of TdTase-mediated extension, in which DNA targets are polymerized in homogeneous solution and then hybridized with DNA probes on BSA-based DNA carrier platform. It is surprising to find that the background in the grafting-to mode of TdTase-based electrochemical DNA biosensor have little interference from the employed TdTase. Most importantly, the proposed electrochemical DNA biosensor shows greatly improved detection performance over the in-situ polymerization approach-based electrochemical DNA biosensor. Copyright © 2017 Elsevier B.V. All rights reserved.

Catalyst–substrate interaction and growth delay in vapor–liquid–solid nanowire growth

NASA Astrophysics Data System (ADS)

Kolíbal, Miroslav; Pejchal, Tomáš; Musálek, Tomáš; Šikola, Tomáš

2018-05-01

Understanding of the initial stage of nanowire growth on a bulk substrate is crucial for the rational design of nanowire building blocks in future electronic and optoelectronic devices. Here, we provide in situ scanning electron microscopy and Auger microscopy analysis of the initial stage of Au-catalyzed Ge nanowire growth on different substrates. Real-time microscopy imaging and elementally resolved spectroscopy clearly show that the catalyst dissolves the underlying substrate if held above a certain temperature. If the substrate dissolution is blocked (or in the case of heteroepitaxy) the catalyst needs to be filled with nanowire material from the external supply, which significantly increases the initial growth delay. The experiments presented here reveal the important role of the substrate in metal-catalyzed nanowire growth and pave the way for different growth delay mitigation strategies.

Catalyst-substrate interaction and growth delay in vapor-liquid-solid nanowire growth.

PubMed

Kolíbal, Miroslav; Pejchal, Tomáš; Musálek, Tomáš; Šikola, Tomáš

2018-05-18

Understanding of the initial stage of nanowire growth on a bulk substrate is crucial for the rational design of nanowire building blocks in future electronic and optoelectronic devices. Here, we provide in situ scanning electron microscopy and Auger microscopy analysis of the initial stage of Au-catalyzed Ge nanowire growth on different substrates. Real-time microscopy imaging and elementally resolved spectroscopy clearly show that the catalyst dissolves the underlying substrate if held above a certain temperature. If the substrate dissolution is blocked (or in the case of heteroepitaxy) the catalyst needs to be filled with nanowire material from the external supply, which significantly increases the initial growth delay. The experiments presented here reveal the important role of the substrate in metal-catalyzed nanowire growth and pave the way for different growth delay mitigation strategies.

Strong polarization-dependent terahertz modulation of aligned Ag nanowires on Si substrate.

PubMed

Lee, Gyuseok; Maeng, Inhee; Kang, Chul; Oh, Myoung-Kyu; Kee, Chul-Sik

2018-05-14

Optically tunable, strong polarization-dependent transmission of terahertz pulses through aligned Ag nanowires on a Si substrate is demonstrated. Terahertz pulses primarily pass through the Ag nanowires and the transmittance is weakly dependent on the angle between the direction of polarization of the terahertz pulse and the direction of nanowire alignment. However, the transmission of a terahertz pulse through optically excited materials strongly depends on the polarization direction. The extinction ratio increases as the power of the pumping laser increases. The enhanced polarization dependency is explained by the redistribution of photocarriers, which accelerates the sintering effect along the direction of alignment of the Ag nanowires. The photocarrier redistribution effect is examined by the enhancement of terahertz emission from the sample. Oblique metal nanowires on Si could be utilized for designing optically tunable terahertz polarization modulators.

Epitaxy of semiconductor-superconductor nanowires

NASA Astrophysics Data System (ADS)

Krogstrup, P.; Ziino, N. L. B.; Chang, W.; Albrecht, S. M.; Madsen, M. H.; Johnson, E.; Nygård, J.; Marcus, C. M.; Jespersen, T. S.

2015-04-01

Controlling the properties of semiconductor/metal interfaces is a powerful method for designing functionality and improving the performance of electrical devices. Recently semiconductor/superconductor hybrids have appeared as an important example where the atomic scale uniformity of the interface plays a key role in determining the quality of the induced superconducting gap. Here we present epitaxial growth of semiconductor-metal core-shell nanowires by molecular beam epitaxy, a method that provides a conceptually new route to controlled electrical contacting of nanostructures and the design of devices for specialized applications such as topological and gate-controlled superconducting electronics. Our materials of choice, InAs/Al grown with epitaxially matched single-plane interfaces, and alternative semiconductor/metal combinations allowing epitaxial interface matching in nanowires are discussed. We formulate the grain growth kinetics of the metal phase in general terms of continuum parameters and bicrystal symmetries. The method realizes the ultimate limit of uniform interfaces and seems to solve the soft-gap problem in superconducting hybrid structures.

Recombinant antibodies and their use in biosensors.

PubMed

Zeng, Xiangqun; Shen, Zhihong; Mernaugh, Ray

2012-04-01

Inexpensive, noninvasive immunoassays can be used to quickly detect disease in humans. Immunoassay sensitivity and specificity are decidedly dependent upon high-affinity, antigen-specific antibodies. Antibodies are produced biologically. As such, antibody quality and suitability for use in immunoassays cannot be readily determined or controlled by human intervention. However, the process through which high-quality antibodies can be obtained has been shortened and streamlined by use of genetic engineering and recombinant antibody techniques. Antibodies that traditionally take several months or more to produce when animals are used can now be developed in a few weeks as recombinant antibodies produced in bacteria, yeast, or other cell types. Typically most immunoassays use two or more antibodies or antibody fragments to detect antigens that are indicators of disease. However, a label-free biosensor, for example, a quartz-crystal microbalance (QCM) needs one antibody only. As such, the cost and time needed to design and develop an immunoassay can be substantially reduced if recombinant antibodies and biosensors are used rather than traditional antibody and assay (e.g. enzyme-linked immunosorbant assay, ELISA) methods. Unlike traditional antibodies, recombinant antibodies can be genetically engineered to self-assemble on biosensor surfaces, at high density, and correctly oriented to enhance antigen-binding activity and to increase assay sensitivity, specificity, and stability. Additionally, biosensor surface chemistry and physical and electronic properties can be modified to further increase immunoassay performance above and beyond that obtained by use of traditional methods. This review describes some of the techniques investigators have used to develop highly specific and sensitive, recombinant antibody-based biosensors for detection of antigens in simple or complex biological samples.

Effect of nanowire curviness on the percolation resistivity of transparent, conductive metal nanowire networks

NASA Astrophysics Data System (ADS)

Hicks, Jeremy; Li, Junying; Ying, Chen; Ural, Ant

2018-05-01

We study the effect of nanowire curviness on the percolation resistivity of transparent, conductive metal nanowire networks by Monte Carlo simulations. We generate curvy nanowires as one-dimensional sticks using 3rd-order Bézier curves. The degree of curviness in the network is quantified by the concept of curviness angle and curl ratio. We systematically study the interaction between the effect of curviness and five other nanowire/device parameters on the network resistivity, namely nanowire density, nanowire length, device length, device width, and nanowire alignment. We find that the resistivity exhibits a power law dependence on the curl ratio, which is a signature of percolation transport. In each case, we extract the power-law scaling critical exponents and explain the results using geometrical and physical arguments. The value of the curl ratio critical exponent is not universal, but increases as the other nanowire/device parameters drive the network toward the percolation threshold. We find that, for randomly oriented networks, curviness is undesirable since it increases the resistivity. For well-aligned networks, on the other hand, some curviness is highly desirable, since the resistivity minimum occurs for partially curvy nanowires. We explain these results by considering the two competing effects of curviness on the percolation resistivity. The results presented in this work can be extended to any network, film, or nanocomposite consisting of one-dimensional nanoelements. Our results show that Monte Carlo simulations are an essential predictive tool for both studying the percolation transport and optimizing the electronic properties of transparent, conductive nanowire networks for a wide range of applications.

Characterization of Textile-Insulated Capacitive Biosensors

PubMed Central

Ng, Charn Loong; Reaz, Mamun Bin Ibne

2017-01-01

Capacitive biosensors are an emerging technology revolutionizing wearable sensing systems and personal healthcare devices. They are capable of continuously measuring bioelectrical signals from the human body while utilizing textiles as an insulator. Different textile types have their own unique properties that alter skin-electrode capacitance and the performance of capacitive biosensors. This paper aims to identify the best textile insulator to be used with capacitive biosensors by analysing the characteristics of 6 types of common textile materials (cotton, linen, rayon, nylon, polyester, and PVC-textile) while evaluating their impact on the performance of a capacitive biosensor. A textile-insulated capacitive (TEX-C) biosensor was developed and validated on 3 subjects. Experimental results revealed that higher skin-electrode capacitance of a TEX-C biosensor yields a lower noise floor and better signal quality. Natural fabric such as cotton and linen were the two best insulating materials to integrate with a capacitive biosensor. They yielded the lowest noise floor of 2 mV and achieved consistent electromyography (EMG) signals measurements throughout the performance test. PMID:28287493

Porous photonic crystal external cavity laser biosensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Qinglan; Peh, Jessie; Hergenrother, Paul J.

2016-08-15

We report the design, fabrication, and testing of a photonic crystal (PC) biosensor structure that incorporates a porous high refractive index TiO{sub 2} dielectric film that enables immobilization of capture proteins within an enhanced surface-area volume that spatially overlaps with the regions of resonant electromagnetic fields where biomolecular binding can produce the greatest shifts in photonic crystal resonant wavelength. Despite the nanoscale porosity of the sensor structure, the PC slab exhibits narrowband and high efficiency resonant reflection, enabling the structure to serve as a wavelength-tunable element of an external cavity laser. In the context of sensing small molecule interactions withmore » much larger immobilized proteins, we demonstrate that the porous structure provides 3.7× larger biosensor signals than an equivalent nonporous structure, while the external cavity laser (ECL) detection method provides capability for sensing picometer-scale shifts in the PC resonant wavelength caused by small molecule binding. The porous ECL achieves a record high figure of merit for label-free optical biosensors.« less

ZnO-Based Amperometric Enzyme Biosensors

PubMed Central

Zhao, Zhiwei; Lei, Wei; Zhang, Xiaobing; Wang, Baoping; Jiang, Helong

2010-01-01

Nanostructured ZnO with its unique properties could provide a suitable microenvironment for immobilization of enzymes while retaining their biological activity, and thus lead to an expanded use of this nanomaterial for the construction of electrochemical biosensors with enhanced analytical performance. ZnO-based enzyme electrochemical biosensors are summarized in several tables for an easy overview according to the target biosensing analyte (glucose, hydrogen peroxide, phenol and cholesterol), respectively. Moreover, recent developments in enzyme electrochemical biosensors based on ZnO nanomaterials are reviewed with an emphasis on the fabrications and features of ZnO, approaches for biosensor construction (e.g., modified electrodes and enzyme immobilization) and biosensor performances. PMID:22205864

A smart dust biosensor powered by kinesin motors.

PubMed

Fischer, Thorsten; Agarwal, Ashutosh; Hess, Henry

2009-03-01

Biosensors can be miniaturized by either injecting smaller volumes into micro- and nanofluidic devices or immersing increasingly sophisticated particles known as 'smart dust' into the sample. The term 'smart dust' originally referred to cubic-millimetre wireless semiconducting sensor devices that could invisibly monitor the environment in buildings and public spaces, but later it also came to include functional micrometre-sized porous silicon particles used to monitor yet smaller environments. The principal challenge in designing smart dust biosensors is integrating transport functions with energy supply into the device. Here, we report a hybrid microdevice that is powered by ATP and relies on antibody-functionalized microtubules and kinesin motors to transport the target analyte into a detection region. The transport step replaces the wash step in traditional double-antibody sandwich assays. Owing to their small size and autonomous function, we envision that large numbers of such smart dust biosensors could be inserted into organisms or distributed into the environment for remote sensing.

Room-temperature InP/InAsP Quantum Discs-in-Nanowire Infrared Photodetectors.

PubMed

Karimi, Mohammad; Jain, Vishal; Heurlin, Magnus; Nowzari, Ali; Hussain, Laiq; Lindgren, David; Stehr, Jan Eric; Buyanova, Irina A; Gustafsson, Anders; Samuelson, Lars; Borgström, Magnus T; Pettersson, Håkan

2017-06-14

The possibility to engineer nanowire heterostructures with large bandgap variations is particularly interesting for technologically important broadband photodetector applications. Here we report on a combined study of design, fabrication, and optoelectronic properties of infrared photodetectors comprising four million n + -i-n + InP nanowires periodically ordered in arrays. The nanowires were grown by metal-organic vapor phase epitaxy on InP substrates, with either a single or 20 InAsP quantum discs embedded in the i-segment. By Zn compensation of the residual n-dopants in the i-segment, the room-temperature dark current is strongly suppressed to a level of pA/NW at 1 V bias. The low dark current is manifested in the spectrally resolved photocurrent measurements, which reveal strong photocurrent contributions from the InAsP quantum discs at room temperature with a threshold wavelength of about 2.0 μm and a bias-tunable responsivity reaching 7 A/W@1.38 μm at 2 V bias. Two different processing schemes were implemented to study the effects of radial self-gating in the nanowires induced by the nanowire/SiO x /ITO wrap-gate geometry. Summarized, our results show that properly designed axial InP/InAsP nanowire heterostructures are promising candidates for broadband photodetectors.

Quantum optics with nanowires (Conference Presentation)

NASA Astrophysics Data System (ADS)

Zwiller, Val

2017-02-01

Nanowires offer new opportunities for nanoscale quantum optics; the quantum dot geometry in semiconducting nanowires as well as the material composition and environment can be engineered with unprecedented freedom to improve the light extraction efficiency. Quantum dots in nanowires are shown to be efficient single photon sources, in addition because of the very small fine structure splitting, we demonstrate the generation of entangled pairs of photons from a nanowire. By doping a nanowire and making ohmic contacts on both sides, a nanowire light emitting diode can be obtained with a single quantum dot as the active region. Under forward bias, this will act as an electrically pumped source of single photons. Under reverse bias, an avalanche effect can multiply photocurrent and enables the detection of single photons. Another type of nanowire under study in our group is superconducting nanowires for single photon detection, reaching efficiencies, time resolution and dark counts beyond currently available detectors. We will discuss our first attempts at combining semiconducting nanowire based single photon emitters and superconducting nanowire single photon detectors on a chip to realize integrated quantum circuits.

Open Loop Structure Low Cost Integrated Differential Inductive Micro Magnetic Volumetric Bio-Sensors

NASA Astrophysics Data System (ADS)

Khodadadi, Mohammad; Chang, Long; Litvinov, Dimitri

This investigation proposes a study, model, simulate and experiment innovative very low cost Magnetic induction biosensor for point of care diagnostics. The biosensor consists of 2 ``semi-loops'' in a micro fluidic channel, one as a sensor and one as a reference, the design takes advantage of microfabrication processes to produce more precise structures to improve sensitivity. Besides the attractively low cost, this biosensor has many advantages. Since the detector is basically a shaped wire, it is inherently robust and reliable. Typical errors in fabricating the wires will not affect its performance and it is sensing volumetric, unlike GMR-based sensors used in biosensor systems that boast single particle detection. Due to small dimensions the sensors do not need to be calibrated. This sensor also has a large range of detection since its sensitivity is proportional to the excitation frequency. Being able to sense Magnetic nano particles in the volume is an advantage in term of trapping MNPs and sensitivity and functionality. Basically, this new brilliant design, fill the gap between the fabricated sensors and hand wounded sensors.

Piezoresistive boron doped diamond nanowire

DOEpatents

Sumant, Anirudha V.; Wang, Xinpeng

2017-07-04

A UNCD nanowire comprises a first end electrically coupled to a first contact pad which is disposed on a substrate. A second end is electrically coupled to a second contact pad also disposed on the substrate. The UNCD nanowire is doped with a dopant and disposed over the substrate. The UNCD nanowire is movable between a first configuration in which no force is exerted on the UNCD nanowire and a second configuration in which the UNCD nanowire bends about the first end and the second end in response to a force. The UNCD nanowire has a first resistance in the first configuration and a second resistance in the second configuration which is different from the first resistance. The UNCD nanowire is structured to have a gauge factor of at least about 70, for example, in the range of about 70 to about 1,800.

Piezoresistive boron doped diamond nanowire

DOEpatents

Sumant, Anirudha V.; Wang, Xinpeng

2016-09-13

A UNCD nanowire comprises a first end electrically coupled to a first contact pad which is disposed on a substrate. A second end is electrically coupled to a second contact pad also disposed on the substrate. The UNCD nanowire is doped with a dopant and disposed over the substrate. The UNCD nanowire is movable between a first configuration in which no force is exerted on the UNCD nanowire and a second configuration in which the UNCD nanowire bends about the first end and the second end in response to a force. The UNCD nanowire has a first resistance in the first configuration and a second resistance in the second configuration which is different from the first resistance. The UNCD nanowire is structured to have a gauge factor of at least about 70, for example, in the range of about 70 to about 1,800.

Guided-Wave Optical Biosensors

PubMed Central

Passaro, Vittorio M. N.; Dell'Olio, Francesco; Casamassima, Biagio; De Leonardis, Francesco

2007-01-01

Guided-wave optical biosensors are reviewed in this paper. Advantages related to optical technologies are presented and integrated architectures are investigated in detail. Main classes of bio receptors and the most attractive optical transduction mechanisms are discussed. The possibility to use Mach-Zehnder and Young interferometers, microdisk and microring resonators, surface plasmon resonance, hollow and antiresonant waveguides, and Bragg gratings to realize very sensitive and selective, ultra-compact and fast biosensors is discussed. Finally, CMOS-compatible technologies are proved to be the most attractive for fabrication of guided-wave photonic biosensors.

Potentiometric Biosensor for Studying Hydroquinone Cytotoxicity in vitro

PubMed Central

Wang, Yanyan; Chen, Qiang; Zeng, Xiangqun

2009-01-01

Many processes in living cells have electrochemical characteristics that are suitable for measurement by potentiometric biosensors. Potentiometric biosensors allow non invasive, real-time monitoring of the extracellular environment changes by measuring the potential at cell/sensor interface. This can be used as an indicator for overall cell cytotoxicity. The present work employs a potentiometric sensor array to investigate the cytotoxicity of hydroquinone to cultured mammalian V79 cells. Various electrode substrates (Au, PPy-HQ and PPy-PS) used for cell growth were designed and characterized. The controllable release of hydroquinone from PPy substrates was studied. Our results showed that hydroquinone exposure affected cell proliferation and delayed cell growth and attachment in a dose-dependent manner. Additionally, we have shown that exposure of V79 cells to hydroquinone at low doses (i.e 5μM) for more than 15 hours allows V79 cells to gain enhanced adaptability to survive exposure to high toxic HQ doses afterwards. Compared with traditional methods, the potentiometric biosensor not only provides non-invasive and real time monitoring of the cellular reactions but also is more sensitive for in vitro cytotoxicity study. By real time and non-invasive monitoring of the extracellular potential in vitro, the potentiometric sensor system represents a promising biosensor system for drug discovery. PMID:19926470

Biosensors for Real-Time Monitoring of Radiation-Induced Biologic Effects in Space

NASA Technical Reports Server (NTRS)

Baker, James R.; Balogh, Lajos; Majoros, Istvan; Keszler, Balazs; Myc, Andrzej; Kukowska-Latallo, Jolanta; Norris, Theodore; delaiglesia, Felix; Beeson, Nicholas W. (Compiler)

2002-01-01

This work seeks to develop cellular biosensors based on dendritic polymers. Nanoscale polymer structures less than 20 nm in diameter will be used as the basis of the biosensors. The structures will be designed to target into specific cells of an astronaut and be able to monitor health issues such as exposure to radiation. Multiple components can be assembled on the polymers including target directors, analytical devices (such as molecular probes), and reporting agents. The reporting will be accomplished through fluorescence signal monitoring, with the use of multispectral analysis for signal interpretation. These nanosensors could facilitate the success and increase the safety of extended space flight. The design and assembly of these devices has been pioneered at the Center for Biologic Nanotechnology in the University of Michigan. This period, synthesis of the test-bed biosensors continued. Studies were performed on the candidate fluorescent dyes to determine which might be suitable for the biosensor under development. Development continued on producing an artificial capillary bed as a tool for the use in the production of the fluorescence signal monitor. Work was also done on the in vitro multispectral analysis system, which uses the robotic microscope.

Surface physics of semiconducting nanowires

NASA Astrophysics Data System (ADS)

Amato, Michele; Rurali, Riccardo

2016-02-01

Semiconducting nanowires (NWs) are firm candidates for novel nanoelectronic devices and a fruitful playground for fundamental physics. Ultra-thin nanowires, with diameters below 10 nm, present exotic quantum effects due to the confinement of the wave functions, e.g. widening of the electronic band-gap, deepening of the dopant states. However, although several reports of sub-10 nm wires exist to date, the most common NWs have diameters that range from 20 to 200 nm, where these quantum effects are absent or play a very minor role. Yet, the research activity on this field is very intense and these materials still promise to provide an important paradigm shift for the design of emerging electronic devices and different kinds of applications. A legitimate question is then: what makes a nanowire different from bulk systems? The answer is certainly the large surface-to-volume ratio. In this article we discuss the most salient features of surface physics and chemistry in group-IV semiconducting nanowires, focusing mostly on Si NWs. First we review the state-of-the-art of NW growth to achieve a smooth and controlled surface morphology. Next we discuss the importance of a proper surface passivation and its role on the NW electronic properties. Finally, stressing the importance of a large surface-to-volume ratio and emphasizing the fact that in a NW the surface is where most of the action takes place, we discuss molecular sensing and molecular doping.

Theoretical analysis of microring resonator-based biosensor with high resolution and free of temperature influence

NASA Astrophysics Data System (ADS)

Jian, Aoqun; Zou, Lu; Tang, Haiquan; Duan, Qianqian; Ji, Jianlong; Zhang, Qianwu; Zhang, Xuming; Sang, Shengbo

2017-06-01

The issue of thermal effects is inevitable for the ultrahigh refractive index (RI) measurement. A biosensor with parallel-coupled dual-microring resonator configuration is proposed to achieve high resolution and free thermal effects measurement. Based on the coupled-resonator-induced transparency effect, the design and principle of the biosensor are introduced in detail, and the performance of the sensor is deduced by simulations. Compared to the biosensor based on a single-ring configuration, the designed biosensor has a 10-fold increased Q value according to the simulation results, thus the sensor is expected to achieve a particularly high resolution. In addition, the output signal of the mathematical model of the proposed sensor can eliminate the thermal influence by adopting an algorithm. This work is expected to have great application potentials in the areas of high-resolution RI measurement, such as biomedical discoveries, virus screening, and drinking water safety.

Introduction to biosensors.

PubMed

Bhalla, Nikhil; Jolly, Pawan; Formisano, Nello; Estrela, Pedro

2016-06-30

Biosensors are nowadays ubiquitous in biomedical diagnosis as well as a wide range of other areas such as point-of-care monitoring of treatment and disease progression, environmental monitoring, food control, drug discovery, forensics and biomedical research. A wide range of techniques can be used for the development of biosensors. Their coupling with high-affinity biomolecules allows the sensitive and selective detection of a range of analytes. We give a general introduction to biosensors and biosensing technologies, including a brief historical overview, introducing key developments in the field and illustrating the breadth of biomolecular sensing strategies and the expansion of nanotechnological approaches that are now available. © 2016 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Angle-dependent photodegradation over ZnO nanowire arrays on flexible paper substrates

PubMed Central

2014-01-01

In this study, we grew zinc oxide (ZnO) nanowire arrays on paper substrates using a two-step growth strategy. In the first step, we formed single-crystalline ZnO nanoparticles of uniform size distribution (ca. 4 nm) as seeds for the hydrothermal growth of the ZnO nanowire arrays. After spin-coating of these seeds onto paper, we grew ZnO nanowire arrays conformally on these substrates. The crystal structure of a ZnO nanowire revealed that the nanowires were single-crystalline and had grown along the c axis. Further visualization through annular bright field scanning transmission electron microscopy revealed that the hydrothermally grown ZnO nanowires possessed Zn polarity. From photocatalytic activity measurements of the ZnO nanowire (NW) arrays on paper substrate, we extracted rate constants of 0.415, 0.244, 0.195, and 0.08 s-1 for the degradation of methylene blue at incident angles of 0°, 30°, 60°, and 75°, respectively; that is, the photocatalytic activity of these ZnO nanowire arrays was related to the cosine of the incident angle of the UV light. Accordingly, these materials have promising applications in the design of sterilization systems and light-harvesting devices. PMID:25593556

Microfluidic-integrated biosensors: prospects for point-of-care diagnostics.

PubMed

Kumar, Suveen; Kumar, Saurabh; Ali, Md Azahar; Anand, Pinki; Agrawal, Ved Varun; John, Renu; Maji, Sagar; Malhotra, Bansi D

2013-11-01

There is a growing demand to integrate biosensors with microfluidics to provide miniaturized platforms with many favorable properties, such as reduced sample volume, decreased processing time, low cost analysis and low reagent consumption. These microfluidics-integrated biosensors would also have numerous advantages such as laminar flow, minimal handling of hazardous materials, multiple sample detection in parallel, portability and versatility in design. Microfluidics involves the science and technology of manipulation of fluids at the micro- to nano-liter level. It is predicted that combining biosensors with microfluidic chips will yield enhanced analytical capability, and widen the possibilities for applications in clinical diagnostics. The recent developments in microfluidics have helped researchers working in industries and educational institutes to adopt some of these platforms for point-of-care (POC) diagnostics. This review focuses on the latest advancements in the fields of microfluidic biosensing technologies, and on the challenges and possible solutions for translation of this technology for POC diagnostic applications. We also discuss the fabrication techniques required for developing microfluidic-integrated biosensors, recently reported biomarkers, and the prospects of POC diagnostics in the medical industry. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Plasmonic engineering of metal-oxide nanowire heterojunctions in integrated nanowire rectification units

NASA Astrophysics Data System (ADS)

Lin, Luchan; Zou, Guisheng; Liu, Lei; Duley, Walt W.; Zhou, Y. Norman

2016-05-01

We show that irradiation with femtosecond laser pulses can produce robust nanowire heterojunctions in coupled non-wetting metal-oxide Ag-TiO2 structures. Simulations indicate that joining arises from the effect of strong plasmonic localization in the region of the junction. Strong electric field effects occur in both Ag and TiO2 resulting in the modification of both surfaces and an increase in wettability of TiO2, facilitating the interconnection of Ag and TiO2 nanowires. Irradiation leads to the creation of a thin layer of highly defected TiO2 in the contact region between the Ag and TiO2 nanowires. The presence of this layer allows the formation of a heterojunction and offers the possibility of engineering the electronic characteristics of interfacial structures. Rectifying junctions with single and bipolar properties have been generated in Ag-TiO2 nanowire circuits incorporating asymmetrical and symmetrical interfacial structures, respectively. This fabrication technique should be applicable for the interconnection of other heterogeneous metal-oxide nanowire components and demonstrates that femtosecond laser irradiation enables interfacial engineering for electronic applications of integrated nanowire structures.

Template-Assisted Scalable Nanowire Networks.

PubMed

Friedl, Martin; Cerveny, Kris; Weigele, Pirmin; Tütüncüoglu, Gozde; Martí-Sánchez, Sara; Huang, Chunyi; Patlatiuk, Taras; Potts, Heidi; Sun, Zhiyuan; Hill, Megan O; Güniat, Lucas; Kim, Wonjong; Zamani, Mahdi; Dubrovskii, Vladimir G; Arbiol, Jordi; Lauhon, Lincoln J; Zumbühl, Dominik M; Fontcuberta I Morral, Anna

2018-04-11

Topological qubits based on Majorana Fermions have the potential to revolutionize the emerging field of quantum computing by making information processing significantly more robust to decoherence. Nanowires are a promising medium for hosting these kinds of qubits, though branched nanowires are needed to perform qubit manipulations. Here we report a gold-free templated growth of III-V nanowires by molecular beam epitaxy using an approach that enables patternable and highly regular branched nanowire arrays on a far greater scale than what has been reported thus far. Our approach relies on the lattice-mismatched growth of InAs on top of defect-free GaAs nanomembranes yielding laterally oriented, low-defect InAs and InGaAs nanowires whose shapes are determined by surface and strain energy minimization. By controlling nanomembrane width and growth time, we demonstrate the formation of compositionally graded nanowires with cross-sections less than 50 nm. Scaling the nanowires below 20 nm leads to the formation of homogeneous InGaAs nanowires, which exhibit phase-coherent, quasi-1D quantum transport as shown by magnetoconductance measurements. These results are an important advance toward scalable topological quantum computing.

Developing Biosensors in Developing Countries: South Africa as a Case Study

PubMed Central

Fogel, Ronen; Limson, Janice

2016-01-01

A mini-review of the reported biosensor research occurring in South Africa evidences a strong emphasis on electrochemical sensor research, guided by the opportunities this transduction platform holds for low-cost and robust sensing of numerous targets. Many of the reported publications centre on fundamental research into the signal transduction method, using model biorecognition elements, in line with international trends. Other research in this field is spread across several areas including: the application of nanotechnology; the identification and validation of biomarkers; development and testing of biorecognition agents (antibodies and aptamers) and design of electro-catalysts, most notably metallophthalocyanine. Biosensor targets commonly featured were pesticides and metals. Areas  of regional import to sub-Saharan Africa, such as HIV/AIDs and tuberculosis diagnosis, are also apparent in a review of the available literature. Irrespective of the targets, the challenge to the effective deployment of such sensors remains shaped by social and economic realities such that the requirements thereof are for low-cost and universally easy to operate devices for field settings. While it is difficult to disentangle the intertwined roles of national policy, grant funding availability and, certainly, of global trends in shaping areas of emphasis in research, most notable is the strong role that nanotechnology, and to a certain extent biotechnology, plays in research regarding biosensor construction. Stronger emphasis on collaboration between scientists in theoretical modelling, nanomaterials application and or relevant stakeholders in the specific field (e.g., food or health monitoring) and researchers in biosensor design may help evolve focused research efforts towards development and deployment of low-cost biosensors. PMID:26848700

Developing Biosensors in Developing Countries: South Africa as a Case Study.

PubMed

Fogel, Ronen; Limson, Janice

2016-02-02

A mini-review of the reported biosensor research occurring in South Africa evidences a strong emphasis on electrochemical sensor research, guided by the opportunities this transduction platform holds for low-cost and robust sensing of numerous targets. Many of the reported publications centre on fundamental research into the signal transduction method, using model biorecognition elements, in line with international trends. Other research in this field is spread across several areas including: the application of nanotechnology; the identification and validation of biomarkers; development and testing of biorecognition agents (antibodies and aptamers) and design of electro-catalysts, most notably metallophthalocyanine. Biosensor targets commonly featured were pesticides and metals. Areas of regional import to sub-Saharan Africa, such as HIV/AIDs and tuberculosis diagnosis, are also apparent in a review of the available literature. Irrespective of the targets, the challenge to the effective deployment of such sensors remains shaped by social and economic realities such that the requirements thereof are for low-cost and universally easy to operate devices for field settings. While it is difficult to disentangle the intertwined roles of national policy, grant funding availability and, certainly, of global trends in shaping areas of emphasis in research, most notable is the strong role that nanotechnology, and to a certain extent biotechnology, plays in research regarding biosensor construction. Stronger emphasis on collaboration between scientists in theoretical modelling, nanomaterials application and or relevant stakeholders in the specific field (e.g., food or health monitoring) and researchers in biosensor design may help evolve focused research efforts towards development and deployment of low-cost biosensors.

Fabrication of Si3N4 nanowire membranes: free standing disordered nanopapers and aligned nanowire assemblies

NASA Astrophysics Data System (ADS)

Liu, Haitao; Fang, Minghao; Huang, Zhaohui; Huang, Juntong; Liu, Yan-gai; Wu, Xiaowen

2016-08-01

Herein, ultralong silicon nitride nanowires were synthesized via a chemical vapor deposition method by using the low-cost quartz and silicon powder as raw materials. Simple processes were used for the fabrication of disordered and ordered nanowire membranes of pure silicon nitride nanowires. The nanowires in the disordered nanopapers are intertwined with each other to form a paper-like structure which exhibit excellent flame retardancy and mechanical properties. Fourier-transform infrared spectroscopy and thermal gravity analysis were employed to characterize the refractory performance of the disordered nanopapers. Highly ordered nanowire membranes were also assembled through a three-phase assembly approach which make the Si3N4 nanowires have potential use in textured ceramics and semiconductor field. Moreover, the surface nanowires can also be modified to be hydrophobic; this characteristic make the as-prepared nanowires have the potential to be assembled by the more effective Langmuir-Blodgett method and also make the disordered nanopapers possess a super-hydrophobic surface.

Microfabricated Electrochemical Cell-Based Biosensors for Analysis of Living Cells In Vitro

PubMed Central

Wang, Jun; Wu, Chengxiong; Hu, Ning; Zhou, Jie; Du, Liping; Wang, Ping

2012-01-01

Cellular biochemical parameters can be used to reveal the physiological and functional information of various cells. Due to demonstrated high accuracy and non-invasiveness, electrochemical detection methods have been used for cell-based investigation. When combined with improved biosensor design and advanced measurement systems, the on-line biochemical analysis of living cells in vitro has been applied for biological mechanism study, drug screening and even environmental monitoring. In recent decades, new types of miniaturized electrochemical biosensor are emerging with the development of microfabrication technology. This review aims to give an overview of the microfabricated electrochemical cell-based biosensors, such as microelectrode arrays (MEA), the electric cell-substrate impedance sensing (ECIS) technique, and the light addressable potentiometric sensor (LAPS). The details in their working principles, measurement systems, and applications in cell monitoring are covered. Driven by the need for high throughput and multi-parameter detection proposed by biomedicine, the development trends of electrochemical cell-based biosensors are also introduced, including newly developed integrated biosensors, and the application of nanotechnology and microfluidic technology. PMID:25585708

Carbon Nanotube Biosensors for Space Molecule Detection and Clinical Molecular Diagnostics

NASA Technical Reports Server (NTRS)

Han, Jie

2001-01-01

Both space molecule detection and clinical molecule diagnostics need to develop ultra sensitive biosensors for detection of less than attomole molecules such as amino acids for DNA. However all the electrode sensor systems including those fabricated from the existing carbon nanotubes, have a background level of nA (nanoAmp). This has limited DNA or other molecule detection to nA level or molecules whose concentration is, much higher than attomole level. A program has been created by NASA and NCI (National Cancer Institute) to exploit the possibility of carbon nanotube based biosensors to solve this problem for both's interest. In this talk, I will present our effort on the evaluation and novel design of carbon nanotubes as electrode biosensors with strategies to minimize background currents while maximizing signal intensity.The fabrication of nanotube electrode arrays, immobilization of molecular probes on nanotube electrodes and in vitro biosensor testing will also be discussed.

Biosensors-on-chip: a topical review

NASA Astrophysics Data System (ADS)

Chen, Sensen; Shamsi, Mohtashim H.

2017-08-01

This review will examine the integration of two fields that are currently at the forefront of science, i.e. biosensors and microfluidics. As a lab-on-a-chip (LOC) technology, microfluidics has been enriched by the integration of various detection tools for analyte detection and quantitation. The application of such microfluidic platforms is greatly increased in the area of biosensors geared towards point-of-care diagnostics. Together, the merger of microfluidics and biosensors has generated miniaturized devices for sample processing and sensitive detection with quantitation. We believe that microfluidic biosensors (biosensors-on-chip) are essential for developing robust and cost effective point-of-care diagnostics. This review is relevant to a variety of disciplines, such as medical science, clinical diagnostics, LOC technologies including MEMs/NEMs, and analytical science. Specifically, this review will appeal to scientists working in the two overlapping fields of biosensors and microfluidics, and will also help new scientists to find their directions in developing point-of-care devices.

Biosensors based on cantilevers.

PubMed

Alvarez, Mar; Carrascosa, Laura G; Zinoviev, Kiril; Plaza, Jose A; Lechuga, Laura M

2009-01-01

Microcantilevers based-biosensors are a new label-free technique that allows the direct detection of biomolecular interactions in a label-less way and with great accuracy by translating the biointeraction into a nanomechanical motion. Low cost and reliable standard silicon technologies are widely used for the fabrication of cantilevers with well-controlled mechanical properties. Over the last years, the number of applications of these sensors has shown a fast growth in diverse fields, such as genomic or proteomic, because of the biosensor flexibility, the low sample consumption, and the non-pretreated samples required. In this chapter, we report a dedicated design and a fabrication process of highly sensitive microcantilever silicon sensors. We will describe as well an application of the device in the environmental field showing the immunodetection of an organic toxic pesticide as an example. The cantilever biofunctionalization process and the subsequent pesticide determination are detected in real time by monitoring the nanometer-scale bending of the microcantilever due to a differential surface stress generated between both surfaces of the device.

Amine oxidase-based biosensors for spermine and spermidine determination.

PubMed

Boffi, Alberto; Favero, Gabriele; Federico, Rodolfo; Macone, Alberto; Antiochia, Riccarda; Tortolini, Cristina; Sanzó, Gabriella; Mazzei, Franco

2015-02-01

The present work describes the development and optimization of electrochemical biosensors for specific determination of the biogenic polyamine spermine (Spm) and spermidine (Spmd) whose assessment represents a novel important analytical tool in food analysis and human diagnostics. These biosensors have been prepared using novel engineered enzymes: polyamine oxidase (PAO) endowed with selectivity towards Spm and Spmd and spermine oxidase (SMO) characterized by strict specificity towards Spm. The current design entails biosensors in which the enzymes were entrapped in poly(vinyl alcohol) bearing styrylpyridinium groups (PVA-SbQ), a photocrosslinkable gel, onto an electrode surface. Screen-printed electrodes (SPEs) were used as electrochemical transducers for enzymatically produced hydrogen peroxide, operating at different potential vs Ag/AgCl according to the material of the working electrode (WE): +700 mV for graphite (GP) or -100 mV for Prussian blue (PB)-modified SPE, respectively. Biosensor performances were evaluated by means of flow injection amperometric (FIA) measurements. The modified electrodes showed good sensitivity, long-term stability and reproducibility. Under optimal conditions, the PAO biosensor showed a linear range 0.003-0.3 mM for Spm and 0.01-0.4 mM for Spmd, while with the SMO biosensor, a linear range of 0.004-0.5 mM for Spm has been obtained. The main kinetic parameters apparent Michaelis constant (K M), turnover number (K cat) and steady-state current (I max) were determined. The proposed device was then applied to the determination of biogenic amines in blood samples. The results obtained were in good agreement with those obtained with the GC-MS reference method.

Bulk nucleation and growth of inorganic nanowires and nanotubes

NASA Astrophysics Data System (ADS)

Sharma, Shashank

The nanometer scale materials such as nanowires and nanotubes will be of particular interest as building blocks for designing novel sensors, catalysts, electronic, optical, and optoelectronic devices. However, in order to realize these applications, bulk amounts of nanowires and nanotubes need to be synthesized with precise control over the nanostructure characteristics. In addition, the structure-property relationships for one-dimensional structures are expected to be different than their bulk when their diameters are less than a characteristic Bohr exciton radius. This fundamental curiosity also necessitates bulk synthesis of nanostructures. The current bulk nanowire synthesis methods utilize either nanometer scale porous molds or nanometer scale transition metal clusters to template one-dimensional growth. All these techniques have inherent limitations in terms of control over the nanowire diameter distribution, composition, the growth direction, and the ability to generate abrupt interfaces within individual nanowires. In this dissertation, a new concept for bulk nucleation and growth of one-dimensional nanostructures is proposed and demonstrated for a variety of inorganic material systems. In this technique, multiple nanowires nucleate and grow from pools of low-melting metal melts when exposed to an activated gas phase containing the necessary precursors. This concept, hereby termed Low Melting Metals and Activated Gas phase (LMAG) mediated method, is specifically demonstrated for the synthesis of, (a) silicon nanowires grown using molten gallium and silane precursors; (b) silicon compound nanowires using solution of molten gallium and appropriate gas phase precursors, and (c) metal-oxide nanostructures grown using direct reaction of the respective metal melts and oxygen precursors. Nanowires resulted from the same molten gallium pool at high densities (>1011/cm2) and with narrow diameter distribution. The silicon nanowires synthesized using the LMAG

Shape Effect in the Design of Nanowire Coated Microparticles as Transepithelial Drug Delivery Devices

PubMed Central

Uskoković, Vuk; Lee, Kunwoo; Lee, Phin Peng; Fischer, Kathleen E.; Desai, Tejal A.

2012-01-01

While the oral drug delivery route has traditionally been the most popular among patients, it is estimated that 90 % of therapeutic compounds possess oral bioavailability limitations. Thus, the development of novel drug carriers for more effective oral delivery of therapeutics is an important goal. Composite particles made by growing nanoscopic silicon wires from the surface of narrowly dispersed, microsized silica beads were previously shown to be able to: (a) adhere well onto the epithelium by interdigitating their nanowires with the apical microvilli; and (b) increase the permeability of Caco-2 cell monolayers with respect to small organic molecules in direct proportion to their concentration. A comparison between the effects of spherical and planar particle morphologies on the permeability of the epithelial cell layer in vitro and in vivo presented the subject of this study. Owing to their larger surface area, the planar particles exhibited a higher drug loading efficiency than their spherical counterparts, while simultaneously increasing the transepithelial permeation of a moderately sized model drug, insulin. The insulin elution profile for planar nanowire-coated particles displayed a continual increase in the cumulative amount of the released drug, approaching a constant release rate for 1 – 4 h period of the elution time. An immunohistochemical study confirmed the ability of planar silica particles coated with nanowires to loosen the tight junction of the epithelial cells to a greater extent than the spherical particles did, thus enabling a more facile transport of the drug across the epithelium. Transepithelial permeability tests conducted for model drugs ranging in size from 0.4 to 150 kDa yielded three categories of molecules depending on their permeation propensities. Insulin belonged to the category of molecules deliverable across the epithelium only with the assistance of nanowire-coated particles. Other groups of drugs, smaller and bigger

Novel image processing method study for a label-free optical biosensor

NASA Astrophysics Data System (ADS)

Yang, Chenhao; Wei, Li'an; Yang, Rusong; Feng, Ying

2015-10-01

Optical biosensor is generally divided into labeled type and label-free type, the former mainly contains fluorescence labeled method and radioactive-labeled method, while fluorescence-labeled method is more mature in the application. The mainly image processing methods of fluorescent-labeled biosensor includes smooth filtering, artificial gridding and constant thresholding. Since some fluorescent molecules may influence the biological reaction, label-free methods have been the main developing direction of optical biosensors nowadays. The using of wider field of view and larger angle of incidence light path which could effectively improve the sensitivity of the label-free biosensor also brought more difficulties in image processing, comparing with the fluorescent-labeled biosensor. Otsu's method is widely applied in machine vision, etc, which choose the threshold to minimize the intraclass variance of the thresholded black and white pixels. It's capacity-constrained with the asymmetrical distribution of images as a global threshold segmentation. In order to solve the irregularity of light intensity on the transducer, we improved the algorithm. In this paper, we present a new image processing algorithm based on a reflectance modulation biosensor platform, which mainly comprises the design of sliding normalization algorithm for image rectification and utilizing the improved otsu's method for image segmentation, in order to implement automatic recognition of target areas. Finally we used adaptive gridding method extracting the target parameters for analysis. Those methods could improve the efficiency of image processing, reduce human intervention, enhance the reliability of experiments and laid the foundation for the realization of high throughput of label-free optical biosensors.

Growing Oxide Nanowires and Nanowire Networks by Solid State Contact Diffusion into Solution-Processed Thin Films.

PubMed

Glynn, Colm; McNulty, David; Geaney, Hugh; O'Dwyer, Colm

2016-11-01

New techniques to directly grow metal oxide nanowire networks without the need for initial nanoparticle seed deposition or postsynthesis nanowire casting will bridge the gap between bottom-up formation and top-down processing for many electronic, photonic, energy storage, and conversion technologies. Whether etched top-down, or grown from catalyst nanoparticles bottom-up, nanowire growth relies on heterogeneous material seeds. Converting surface oxide films, ubiquitous in the microelectronics industry, to nanowires and nanowire networks by the incorporation of extra species through interdiffusion can provide an alternative deposition method. It is shown that solution-processed thin films of oxides can be converted and recrystallized into nanowires and networks of nanowires by solid-state interdiffusion of ionic species from a mechanically contacted donor substrate. NaVO 3 nanowire networks on smooth Si/SiO 2 and granular fluorine-doped tin oxide surfaces can be formed by low-temperature annealing of a Na diffusion species-containing donor glass to a solution-processed V 2 O 5 thin film, where recrystallization drives nanowire growth according to the crystal habit of the new oxide phase. This technique illustrates a new method for the direct formation of complex metal oxide nanowires on technologically relevant substrates, from smooth semiconductors, to transparent conducting materials and interdigitated device structures. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Complex Electric-Field Induced Phenomena in Ferroelectric/Antiferroelectric Nanowires

NASA Astrophysics Data System (ADS)

Herchig, Ryan Christopher

Perovskite ferroelectrics and antiferroelectrics have attracted a lot of attention owing to their potential for device applications including THz sensors, solid state cooling, ultra high density computer memory, and electromechanical actuators to name a few. The discovery of ferroelectricity at the nanoscale provides not only new and exciting possibilities for device miniaturization, but also a way to study the fundamental physics of nanoscale phenomena in these materials. Ferroelectric nanowires show a rich variety of physical characteristics which are advantageous to the design of nanoscale ferroelectric devices such as exotic dipole patterns, a strong dependence of the polarization and phonon frequencies on the electrical and mechanical boundary conditions, as well as a dependence of the transition temperatures on the diameter of the nanowire. Antiferroelectricity also exists at the nanoscale and, due to the proximity in energy of the ferroelectric and antiferroelectric phases, a phase transition from the ferroelectric to the antiferroelectric phase can be facilitated through the application of the appropriate mechanical and electrical boundary conditions. While much progress has been made over the past several decades to understand the nature of ferroelectricity/antiferroelectricity in nanowires, many questions remain unanswered. In particular, little is known about how the truncated dimensions affect the soft mode frequency dynamics or how various electrical and mechanical boundary conditions might change the nature of the phase transitions in these ferroelectric nanowires. Could nanowires offer a distinct advantage for solid state cooling applications? Few studies have been done to elucidate the fundamental physics of antiferroelectric nanowires. How the polarization in ferroelectric nanowires responds to a THz electric field remains relatively underexplored as well. In this work, the aim is to to develop and use computational tools that allow first

A silicon nanowire heater and thermometer

NASA Astrophysics Data System (ADS)

Zhao, Xingyan; Dan, Yaping

2017-07-01

In the thermal conductivity measurements of thermoelectric materials, heaters and thermometers made of the same semiconducting materials under test, forming a homogeneous system, will significantly simplify fabrication and integration. In this work, we demonstrate a high-performance heater and thermometer made of single silicon nanowires (SiNWs). The SiNWs are patterned out of a silicon-on-insulator wafer by CMOS-compatible fabrication processes. The electronic properties of the nanowires are characterized by four-probe and low temperature Hall effect measurements. The I-V curves of the nanowires are linear at small voltage bias. The temperature dependence of the nanowire resistance allows the nanowire to be used as a highly sensitive thermometer. At high voltage bias, the I-V curves of the nanowire become nonlinear due to the effect of Joule heating. The temperature of the nanowire heater can be accurately monitored by the nanowire itself as a thermometer.

Synthesis and characterization of axial heterojunction inorganic-organic semiconductor nanowire arrays.

PubMed

Chen, Nan; Qian, Xuemin; Lin, Haowei; Liu, Huibiao; Li, Yongjun; Li, Yuliang

2011-11-07

The end-to-end P-N heterojunction nanowire arrays combined organic (poly[1,4-bis(pyrrol-2-yl)benzene], BPB) and inorganic (CdS) molecules have been successfully designed and fabricated. The electrical properties of P-N heterojunctions of organic-inorganic nanowire arrays were investigated. The diode nature and rectifying feature of P-N heterojunction nanowire arrays were observed. The rectification ratio of the diode increased from 29.9 to 129.7 as the illumination intensity increased. The material exhibits a new property, which is an improvement in the integration of the physical and chemical properties of the two independent components.

Designing Diameter-Modulated Heterostructure Nanowires of PbTe/Te by Controlled Dewetting.

PubMed

Kumar, Abinash; Kundu, Subhajit; Samantaray, Debadarshini; Kundu, Paromita; Zanaga, Daniele; Bals, Sara; Ravishankar, N

2017-12-13

Heterostructures consisting of semiconductors with controlled morphology and interfaces find applications in many fields. A range of axial, radial, and diameter-modulated nanostructures have been synthesized primarily using vapor phase methods. Here, we present a simple wet chemical routine to synthesize heterostructures of PbTe/Te using Te nanowires as templates. A morphology evolution study for the formation of these heterostructures has been performed. On the basis of these control experiments, a pathway for the formation of these nanostructures is proposed. Reduction of a Pb precursor to Pb on Te nanowire templates followed by interdiffusion of Pb/Te leads to the formation of a thin shell of PbTe on the Te wires. Controlled dewetting of the thin shell leads to the formation of cube-shaped PbTe that is periodically arranged on the Te wires. Using control experiments, we show that different reactions parameters like rate of addition of the reducing agent, concentration of Pb precursor and thickness of initial Te nanowire play a critical role in controlling the spacing between the PbTe cubes on the Te wires. Using simple surface energy arguments, we propose a mechanism for the formation of the hybrid. The principles presented are general and can be exploited for the synthesis of other nanoscale heterostructures.

Anomalous resonance in a nanomechanical biosensor

PubMed Central

Gupta, Amit K.; Nair, Pradeep R.; Akin, Demir; Ladisch, Michael R.; Broyles, Steve; Alam, Muhammad A.; Bashir, Rashid

2006-01-01

The decrease in resonant frequency (−Δωr) of a classical cantilever provides a sensitive measure of the mass of entities attached on its surface. This elementary phenomenon has been the basis of a new class of bio-nanomechanical devices as sensing components of integrated microsystems that can perform rapid, sensitive, and selective detection of biological and biochemical entities. Based on classical analysis, there is a widespread perception that smaller sensors are more sensitive (sensitivity ≈ −0.5ωr/mC, where mC is the mass of the cantilever), and this notion has motivated scaling of biosensors to nanoscale dimensions. In this work, we show that the response of a nanomechanical biosensor is far more complex than previously anticipated. Indeed, in contrast to classical microscale sensors, the resonant frequencies of the nanosensor may actually decrease or increase after attachment of protein molecules. We demonstrate theoretically and experimentally that the direction of the frequency change arises from a size-specific modification of diffusion and attachment kinetics of biomolecules on the cantilevers. This work may have broad impact on microscale and nanoscale biosensor design, especially when predicting the characteristics of bio-nanoelectromechanical sensors functionalized with biological capture molecules. PMID:16938886

Construction of 3D Metallic Nanowire Arrays on Arbitrarily-Shaped Substrate.

NASA Astrophysics Data System (ADS)

Chen, Fei; Li, Jingning; Yu, Fangfang; Peng, Ru-Wen; Wang, Mu; Mu Wang Team

Formation of three-dimensional (3D) nanostructures is an important step of advanced manufacture for new concept devices with novel functionality. Despite of great achievements in fabricating nanostructures with state of the art lithography approaches, these nanostructures are normally limited on flat substrates. Up to now it remains challenging to build metallic nanostructures directly on a rough and bumpy surface. Here we demonstrate a unique approach to fabricate metallic nanowire arrays on an arbitrarily-shaped surface by electrodeposition, which is unknown before 2016. Counterintuitively here the growth direction of the nanowires is perpendicular to their longitudinal axis, and the specific geometry of nanowires can be achieved by introducing specially designed shaped substrate. The spatial separation and the width of the nanowires can be tuned by voltage, electrolyte concentration and temperature in electrodeposition. By taking cobalt nanowire array as an example, we demonstrate that head-to-head and tail-to-tail magnetic domain walls can be easily introduced and modulated in the nanowire arrays, which is enlightening to construct new devices such as domain wall racetrack memory. We acknowledge the foundation from MOST and NSF(China).

Wireless implantable electronic platform for chronic fluorescent-based biosensors.

PubMed

Valdastri, Pietro; Susilo, Ekawahyu; Förster, Thilo; Strohhöfer, Christof; Menciassi, Arianna; Dario, Paolo

2011-06-01

The development of a long-term wireless implantable biosensor based on fluorescence intensity measurement poses a number of technical challenges, ranging from biocompatibility to sensor stability over time. One of these challenges is the design of a power efficient and miniaturized electronics, enabling the biosensor to move from bench testing to long term validation, up to its final application in human beings. In this spirit, we present a wireless programmable electronic platform for implantable chronic monitoring of fluorescent-based autonomous biosensors. This system is able to achieve extremely low power operation with bidirectional telemetry, based on the IEEE802.15.4-2003 protocol, thus enabling over three-year battery lifetime and wireless networking of multiple sensors. During the performance of single fluorescent-based sensor measurements, the circuit drives a laser diode, for sensor excitation, and acquires the amplified signals from four different photodetectors. In vitro functionality was preliminarily tested for both glucose and calcium monitoring, simply by changing the analyte-binding protein of the biosensor. Electronics performance was assessed in terms of timing, power consumption, tissue exposure to electromagnetic fields, and in vivo wireless connectivity. The final goal of the presented platform is to be integrated in a complete system for blood glucose level monitoring that may be implanted for at least one year under the skin of diabetic patients. Results reported in this paper may be applied to a wide variety of biosensors based on fluorescence intensity measurement.

Study of GaN nanowires converted from β-Ga2O3 and photoconduction in a single nanowire

NASA Astrophysics Data System (ADS)

Kumar, Mukesh; Kumar, Sudheer; Chauhan, Neha; Sakthi Kumar, D.; Kumar, Vikram; Singh, R.

2017-08-01

The formation of GaN nanowires from β-Ga2O3 nanowires and photoconduction in a fabricated single GaN nanowire device has been studied. Wurtzite phase GaN were formed from monoclinic β-Ga2O3 nanowires with or without catalyst particles at their tips. The formation of faceted nanostructures from catalyst droplets presented on a nanowire tip has been discussed. The nucleation of GaN phases in β-Ga2O3 nanowires and their subsequent growth due to interfacial strain energy has been examined using a high resolution transmission electron microscope. The high quality of the converted GaN nanowire is confirmed by fabricating single nanowire photoconducting devices which showed ultra high responsivity under ultra-violet illumination.

Ultralight Conductive Silver Nanowire Aerogels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qian, Fang; Lan, Pui Ching; Freyman, Megan C.

Low-density metal foams have many potential applications in electronics, energy storage, catalytic supports, fuel cells, sensors, and medical devices. Here in this work, we report a new method for fabricating ultralight, conductive silver aerogel monoliths with predictable densities using silver nanowires. Silver nanowire building blocks were prepared by polyol synthesis and purified by selective precipitation. Silver aerogels were produced by freeze-casting nanowire aqueous suspensions followed by thermal sintering to weld the nanowire junctions. As-prepared silver aerogels have unique anisotropic microporous structures, with density precisely controlled by the nanowire concentration, down to 4.8 mg/cm 3 and an electrical conductivity up tomore » 51 000 S/m. Lastly, mechanical studies show that silver nanowire aerogels exhibit “elastic stiffening” behavior with a Young’s modulus up to 16 800 Pa.« less

Ultralight Conductive Silver Nanowire Aerogels

DOE PAGES

Qian, Fang; Lan, Pui Ching; Freyman, Megan C.; ...

2017-09-05

Low-density metal foams have many potential applications in electronics, energy storage, catalytic supports, fuel cells, sensors, and medical devices. Here in this work, we report a new method for fabricating ultralight, conductive silver aerogel monoliths with predictable densities using silver nanowires. Silver nanowire building blocks were prepared by polyol synthesis and purified by selective precipitation. Silver aerogels were produced by freeze-casting nanowire aqueous suspensions followed by thermal sintering to weld the nanowire junctions. As-prepared silver aerogels have unique anisotropic microporous structures, with density precisely controlled by the nanowire concentration, down to 4.8 mg/cm 3 and an electrical conductivity up tomore » 51 000 S/m. Lastly, mechanical studies show that silver nanowire aerogels exhibit “elastic stiffening” behavior with a Young’s modulus up to 16 800 Pa.« less

A New Laccase Based Biosensor for Tartrazine.

PubMed

Mazlan, Siti Zulaikha; Lee, Yook Heng; Hanifah, Sharina Abu

2017-12-09

Laccase enzyme, a commonly used enzyme for the construction of biosensors for phenolic compounds was used for the first time to develop a new biosensor for the determination of the azo-dye tartrazine. The electrochemical biosensor was based on the immobilization of laccase on functionalized methacrylate-acrylate microspheres. The biosensor membrane is a composite of the laccase conjugated microspheres and gold nanoparticles (AuNPs) coated on a carbon-paste screen-printed electrode. The reaction involving tartrazine can be catalyzed by laccase enzyme, where the current change was measured by differential pulse voltammetry (DPV) at 1.1 V. The anodic peak current was linear within the tartrazine concentration range of 0.2 to 14 μM ( R ² = 0.979) and the detection limit was 0.04 μM. Common food ingredients or additives such as glucose, sucrose, ascorbic acid, phenol and sunset yellow did not interfere with the biosensor response. Furthermore, the biosensor response was stable up to 30 days of storage period at 4 °C. Foods and beverage were used as real samples for the biosensor validation. The biosensor response to tartrazine showed no significant difference with a standard HPLC method for tartrazine analysis.

A New Laccase Based Biosensor for Tartrazine

PubMed Central

Mazlan, Siti Zulaikha; Lee, Yook Heng; Hanifah, Sharina Abu

2017-01-01

Laccase enzyme, a commonly used enzyme for the construction of biosensors for phenolic compounds was used for the first time to develop a new biosensor for the determination of the azo-dye tartrazine. The electrochemical biosensor was based on the immobilization of laccase on functionalized methacrylate-acrylate microspheres. The biosensor membrane is a composite of the laccase conjugated microspheres and gold nanoparticles (AuNPs) coated on a carbon-paste screen-printed electrode. The reaction involving tartrazine can be catalyzed by laccase enzyme, where the current change was measured by differential pulse voltammetry (DPV) at 1.1 V. The anodic peak current was linear within the tartrazine concentration range of 0.2 to 14 μM (R2 = 0.979) and the detection limit was 0.04 μM. Common food ingredients or additives such as glucose, sucrose, ascorbic acid, phenol and sunset yellow did not interfere with the biosensor response. Furthermore, the biosensor response was stable up to 30 days of storage period at 4 °C. Foods and beverage were used as real samples for the biosensor validation. The biosensor response to tartrazine showed no significant difference with a standard HPLC method for tartrazine analysis. PMID:29232842

On the challenges of detecting whole Staphylococcus aureus cells with biosensors.

PubMed

Templier, V; Roupioz, Y

2017-11-01

Due to the increasing number of nosocomial infections and multidrug-resistant bacterial strains, Staphylococcus aureus is now a major worldwide concern. Rapid detection and characterization of this bacterium has become an important issue for biomedical applications. Biosensors are increasingly appearing as low-cost, easy-to-operate and fast alternatives for rapid detection. In this review, we will introduce the main characteristics of S. aureus and will focus on the interest of biosensors for a faster detection of whole S. aureus cells. In particular, we will review the most promising strategies in the choice of ligand for the design of selective and efficient biosensors. Their specific characteristics as well as their advantages and/or disadvantages will also be commented. © 2017 The Society for Applied Microbiology.

Synthesis, fabrication and characterization of Ge/Si axial nanowire heterostructure tunnel FETs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Picraux, Samuel T; Dayeh, Shadi A

2010-01-01

Axial Ge/Si heterostructure nanowires allow energy band-edge engineering along the axis of the nanowire, which is the charge transport direction, and the realization of asymmetric devices for novel device architectures. This work reports on two advances in the area of heterostructure nanowires and tunnel FETs: (i) the realization of 100% compositionally modulated Si/Ge axial heterostructure nanowires with lengths suitable for device fabrication and (ii) the design and implementation of Schottky barrier tunnel FETs on these nanowires for high-on currents and suppressed ambipolar behavior. Initial prototype devices resulted in a current drive in excess of 100 {micro}A/{micro}m (I/{pi}D) and 10{sup 5}more » I{sub on}/I{sub off} ratios. These results demonstrate the potential of such asymmetric heterostructures (both in the semiconductor channel and metal-semiconductor barrier heights) for low-power and high performance electronics.« less

Nanowire mesh solar fuels generator

DOEpatents

Yang, Peidong; Chan, Candace; Sun, Jianwei; Liu, Bin

2016-05-24

This disclosure provides systems, methods, and apparatus related to a nanowire mesh solar fuels generator. In one aspect, a nanowire mesh solar fuels generator includes (1) a photoanode configured to perform water oxidation and (2) a photocathode configured to perform water reduction. The photocathode is in electrical contact with the photoanode. The photoanode may include a high surface area network of photoanode nanowires. The photocathode may include a high surface area network of photocathode nanowires. In some embodiments, the nanowire mesh solar fuels generator may include an ion conductive polymer infiltrating the photoanode and the photocathode in the region where the photocathode is in electrical contact with the photoanode.

Biosensor for metal analysis and speciation

DOEpatents

Aiken, Abigail M.; Peyton, Brent M.; Apel, William A.; Petersen, James N.

2007-01-30

A biosensor for metal analysis and speciation is disclosed. The biosensor comprises an electron carrier immobilized to a surface of an electrode and a layer of an immobilized enzyme adjacent to the electrode. The immobilized enzyme comprises an enzyme having biological activity inhibited by a metal to be detected by the biosensor.

Design and preparation of open circuit potential biosensor for in vitro and in vivo glucose monitoring.

PubMed

Song, Yonggui; Su, Dan; Shen, Yuan; Liu, Hongyu; Wang, Li

2017-01-01

A novel open circuit potential biosensor (OCPS) composed of a working electrode and a Ag/AgCl reference electrode was designed for in vivo continuous glucose monitoring in this work. The macroporous carbon derived from kenaf stem (KSC) was used to construct a KSC microelectrode (denoted as KSCME) which was subsequently used to load glucose oxidase (GOD) as the working electrode. The resulting GOD/KSCMEs could catalyze the oxidation of glucose directly to result in changes of the open circuit potential (V oc ) of the OCPS. The V oc of OCPS was dependent on the glucose concentration, showing a linear range of 0.03-10.0 mM (R = 0.999) with a detection limit of 10 μM. In addition, the OCPS exhibited good selectivity for glucose over other common endogenous interferences. The feasibility of the proposed OCPS for glucose detection in mice skin tumors and normal tissue homogenate samples (in vitro experiment) and rat subcutaneous glucose monitoring (in vivo experiment) was also demonstrated with satisfactory results. The biosensor represents a novel example of a superficial cancer diagnostic device, and the proposed OCPS also provides new ideas for the development of a simple and highly selective device for continuous glucose sensing.

Tailoring the vapor-liquid-solid growth toward the self-assembly of GaAs nanowire junctions.

PubMed

Dai, Xing; Dayeh, Shadi A; Veeramuthu, Vaithianathan; Larrue, Alexandre; Wang, Jian; Su, Haibin; Soci, Cesare

2011-11-09

New insights into understanding and controlling the intriguing phenomena of spontaneous merging (kissing) and the self-assembly of monolithic Y- and T-junctions is demonstrated in the metal-organic chemical vapor deposition growth of GaAs nanowires. High-resolution transmission electron microscopy for determining polar facets was coupled to electrostatic-mechanical modeling and position-controlled synthesis to identify nanowire diameter, length, and pitch, leading to junction formation. When nanowire patterns are designed so that the electrostatic energy resulting from the interaction of polar surfaces exceeds the mechanical energy required to bend the nanowires to the point of contact, their fusion can lead to the self-assembly of monolithic junctions. Understanding and controlling this phenomenon is a great asset for the realization of dense arrays of vertical nanowire devices and opens up new ways toward the large scale integration of nanowire quantum junctions or nanowire intracellular probes.

Nanowire Electron Scattering Spectroscopy

NASA Technical Reports Server (NTRS)

Hunt, Brian; Bronikowsky, Michael; Wong, Eric; VonAllmen, Paul; Oyafuso, Fablano

2009-01-01

Nanowire electron scattering spectroscopy (NESS) has been proposed as the basis of a class of ultra-small, ultralow-power sensors that could be used to detect and identify chemical compounds present in extremely small quantities. State-of-the-art nanowire chemical sensors have already been demonstrated to be capable of detecting a variety of compounds in femtomolar quantities. However, to date, chemically specific sensing of molecules using these sensors has required the use of chemically functionalized nanowires with receptors tailored to individual molecules of interest. While potentially effective, this functionalization requires labor-intensive treatment of many nanowires to sense a broad spectrum of molecules. In contrast, NESS would eliminate the need for chemical functionalization of nanowires and would enable the use of the same sensor to detect and identify multiple compounds. NESS is analogous to Raman spectroscopy, the main difference being that in NESS, one would utilize inelastic scattering of electrons instead of photons to determine molecular vibrational energy levels. More specifically, in NESS, one would exploit inelastic scattering of electrons by low-lying vibrational quantum states of molecules attached to a nanowire or nanotube.

Robust ultrasensitive tunneling-FET biosensor for point-of-care diagnostics

PubMed Central

Gao, Anran; Lu, Na; Wang, Yuelin; Li, Tie

2016-01-01

For point-of-care (POC) applications, robust, ultrasensitive, small, rapid, low-power, and low-cost sensors are highly desirable. Here, we present a novel biosensor based on a complementary metal oxide semiconductor (CMOS)-compatible silicon nanowire tunneling field-effect transistor (SiNW-TFET). They were fabricated “top-down” with a low-cost anisotropic self-stop etching technique. Notably, the SiNW-TFET device provided strong anti-interference capacity by applying the inherent ambipolarity via both pH and CYFRA21-1 sensing. This offered a more robust and portable general protocol. The specific label-free detection of CYFRA21-1 down to 0.5 fgml−1 or ~12.5 aM was achieved using a highly responsive SiNW-TFET device with a minimum sub-threshold slope (SS) of 37 mVdec−1. Furthermore, real-time measurements highlighted the ability to use clinically relevant samples such as serum. The developed high performance diagnostic system is expected to provide a generic platform for numerous POC applications. PMID:26932158

Synthetic biology and biomimetic chemistry as converging technologies fostering a new generation of smart biosensors.

PubMed

Scognamiglio, Viviana; Antonacci, Amina; Lambreva, Maya D; Litescu, Simona C; Rea, Giuseppina

2015-12-15

Biosensors are powerful tunable systems able to switch between an ON/OFF status in response to an external stimulus. This extraordinary property could be engineered by adopting synthetic biology or biomimetic chemistry to obtain tailor-made biosensors having the desired requirements of robustness, sensitivity and detection range. Recent advances in both disciplines, in fact, allow to re-design the configuration of the sensing elements - either by modifying toggle switches and gene networks, or by producing synthetic entities mimicking key properties of natural molecules. The present review considered the role of synthetic biology in sustaining biosensor technology, reporting examples from the literature and reflecting on the features that make it a useful tool for designing and constructing engineered biological systems for sensing application. Besides, a section dedicated to bioinspired synthetic molecules as powerful tools to enhance biosensor potential is reported, and treated as an extension of the concept of biomimetic chemistry, where organic synthesis is used to generate artificial molecules that mimic natural molecules. Thus, the design of synthetic molecules, such as aptamers, biomimetics, molecular imprinting polymers, peptide nucleic acids, and ribozymes were encompassed as "products" of biomimetic chemistry. Copyright © 2015 Elsevier B.V. All rights reserved.

Electronic Biosensors Based on III-Nitride Semiconductors.

PubMed

Kirste, Ronny; Rohrbaugh, Nathaniel; Bryan, Isaac; Bryan, Zachary; Collazo, Ramon; Ivanisevic, Albena

2015-01-01

We review recent advances of AlGaN/GaN high-electron-mobility transistor (HEMT)-based electronic biosensors. We discuss properties and fabrication of III-nitride-based biosensors. Because of their superior biocompatibility and aqueous stability, GaN-based devices are ready to be implemented as next-generation biosensors. We review surface properties, cleaning, and passivation as well as different pathways toward functionalization, and critically analyze III-nitride-based biosensors demonstrated in the literature, including those detecting DNA, bacteria, cancer antibodies, and toxins. We also discuss the high potential of these biosensors for monitoring living cardiac, fibroblast, and nerve cells. Finally, we report on current developments of covalent chemical functionalization of III-nitride devices. Our review concludes with a short outlook on future challenges and projected implementation directions of GaN-based HEMT biosensors.

S-Layer Protein-Based Biosensors.

PubMed

Schuster, Bernhard

2018-04-11

The present paper highlights the application of bacterial surface (S-) layer proteins as versatile components for the fabrication of biosensors. One technologically relevant feature of S-layer proteins is their ability to self-assemble on many surfaces and interfaces to form a crystalline two-dimensional (2D) protein lattice. The S-layer lattice on the surface of a biosensor becomes part of the interface architecture linking the bioreceptor to the transducer interface, which may cause signal amplification. The S-layer lattice as ultrathin, highly porous structure with functional groups in a well-defined special distribution and orientation and an overall anti-fouling characteristics can significantly raise the limit in terms of variety and the ease of bioreceptor immobilization, compactness of bioreceptor molecule arrangement, sensitivity, specificity, and detection limit for many types of biosensors. The present paper discusses and summarizes examples for the successful implementation of S-layer lattices on biosensor surfaces in order to give a comprehensive overview on the application potential of these bioinspired S-layer protein-based biosensors.

Silicon nanowires as field-effect transducers for biosensor development: a review.

PubMed

Noor, M Omair; Krull, Ulrich J

2014-05-12

The unique electronic properties and miniaturized dimensions of silicon nanowires (SiNWs) are attractive for label-free, real-time and sensitive detection of biomolecules. Sensors based on SiNWs operate as field effect transistors (FETs) and can be fabricated either by top-down or bottom-up approaches. Advances in fabrication methods have allowed for the control of physicochemical and electronic properties of SiNWs, providing opportunity for interfacing of SiNW-FET probes with intracellular environments. The Debye screening length is an important consideration that determines the performance and detection limits of SiNW-FET sensors, especially at physiologically relevant conditions of ionic strength (>100mM). In this review, we discuss the construction and application of SiNW-FET sensors for detection of ions, nucleic acids and protein markers. Advantages and disadvantages of the top-down and bottom-up approaches for synthesis of SiNWs are discussed. An overview of various methods for surface functionalization of SiNWs for immobilization of selective chemistry is provided in the context of impact on the analytical performance of SiNW-FET sensors. In addition to in vitro examples, an overview of the progress of use of SiNW-FET sensors for ex vivo studies is also presented. This review concludes with a discussion of the future prospects of SiNW-FET sensors. Copyright © 2014 Elsevier B.V. All rights reserved.

Versatile graphene biosensors for enhancing human cell therapy.

PubMed

Vlăsceanu, George M; Amărandi, Roxana-Maria; Ioniță, Mariana; Tite, Teddy; Iovu, Horia; Pilan, Luisa; Burns, Jorge S

2018-05-01

Technological advances in engineering and cell biology stimulate novel approaches for medical treatment, in particular cell-based therapy. The first cell-based gene therapy against cancer was recently approved by the US Food and Drug Administration. Progress in cancer diagnosis includes a blood test detecting five cancer types. Numerous stem cell phase I/II clinical trials showing safety and efficacy will soon pursue qualifying criteria for advanced therapy medicinal products (ATMP), aspiring to join the first stem-cell therapy approved by the European Medicines Agency. Cell based therapy requires extensive preclinical characterisation of biomarkers indicating mechanisms of action crucial to the desired therapeutic effect. Quantitative analyses monitoring critical functions for the manufacture of optimal cell and tissue-based clinical products include successful potency assays for implementation. The challenge to achieve high quality measurement is increasingly met by progress in biosensor design. We adopt a cell therapy perspective to highlight recent examples of graphene-enhanced biointerfaces for measurement of biomarkers relevant to cancer treatment, diagnosis and tissue regeneration. Graphene based biosensor design problems can thwart their use for health care transformative point of care testing and real-time applications. We discuss concerns to be addressed and emerging solutions for establishing clinical grade biosensors to accelerate human cell therapy. Copyright © 2018 Elsevier B.V. All rights reserved.

Skin-like biosensor system via electrochemical channels for noninvasive blood glucose monitoring.

PubMed

Chen, Yihao; Lu, Siyuan; Zhang, Shasha; Li, Yan; Qu, Zhe; Chen, Ying; Lu, Bingwei; Wang, Xinyan; Feng, Xue

2017-12-01

Currently, noninvasive glucose monitoring is not widely appreciated because of its uncertain measurement accuracy, weak blood glucose correlation, and inability to detect hyperglycemia/hypoglycemia during sleep. We present a strategy to design and fabricate a skin-like biosensor system for noninvasive, in situ, and highly accurate intravascular blood glucose monitoring. The system integrates an ultrathin skin-like biosensor with paper battery-powered electrochemical twin channels (ETCs). The designed subcutaneous ETCs drive intravascular blood glucose out of the vessel and transport it to the skin surface. The ultrathin (~3 μm) nanostructured biosensor, with high sensitivity (130.4 μA/mM), fully absorbs and measures the glucose, owing to its extreme conformability. We conducted in vivo human clinical trials. The noninvasive measurement results for intravascular blood glucose showed a high correlation (>0.9) with clinically measured blood glucose levels. The system opens up new prospects for clinical-grade noninvasive continuous glucose monitoring.

Skin-like biosensor system via electrochemical channels for noninvasive blood glucose monitoring

PubMed Central

Chen, Yihao; Lu, Siyuan; Zhang, Shasha; Li, Yan; Qu, Zhe; Chen, Ying; Lu, Bingwei; Wang, Xinyan; Feng, Xue

2017-01-01

Currently, noninvasive glucose monitoring is not widely appreciated because of its uncertain measurement accuracy, weak blood glucose correlation, and inability to detect hyperglycemia/hypoglycemia during sleep. We present a strategy to design and fabricate a skin-like biosensor system for noninvasive, in situ, and highly accurate intravascular blood glucose monitoring. The system integrates an ultrathin skin-like biosensor with paper battery–powered electrochemical twin channels (ETCs). The designed subcutaneous ETCs drive intravascular blood glucose out of the vessel and transport it to the skin surface. The ultrathin (~3 μm) nanostructured biosensor, with high sensitivity (130.4 μA/mM), fully absorbs and measures the glucose, owing to its extreme conformability. We conducted in vivo human clinical trials. The noninvasive measurement results for intravascular blood glucose showed a high correlation (>0.9) with clinically measured blood glucose levels. The system opens up new prospects for clinical-grade noninvasive continuous glucose monitoring. PMID:29279864

The controlled growth of GaN nanowires.

PubMed

Hersee, Stephen D; Sun, Xinyu; Wang, Xin

2006-08-01

This paper reports a scalable process for the growth of high-quality GaN nanowires and uniform nanowire arrays in which the position and diameter of each nanowire is precisely controlled. The approach is based on conventional metalorganic chemical vapor deposition using regular precursors and requires no additional metal catalyst. The location, orientation, and diameter of each GaN nanowire are controlled using a thin, selective growth mask that is patterned by interferometric lithography. It was found that use of a pulsed MOCVD process allowed the nanowire diameter to remain constant after the nanowires had emerged from the selective growth mask. Vertical GaN nanowire growth rates in excess of 2 mum/h were measured, while remarkably the diameter of each nanowire remained constant over the entire (micrometer) length of the nanowires. The paper reports transmission electron microscopy and photoluminescence data.

Synthesis and transport characterization of electrochemically deposited CdTe nanowires

NASA Astrophysics Data System (ADS)

Kaur, Jaskiran; Kaur, Harmanmeet; Singh, R. C.

2018-04-01

This paper reports the synthesis and characterization of CdTe nanowires. A thin polymeric films were irradiated with 80MeV Ag ions at a fluence of 8E7 ions/cm2, followed by UV irradiation and chemically etching in aqueous NaOH. Nanosizes go-through pores so formed were filled using a specially designed cell via electrodeposition. Nanowires so formed were further studied using SEM, I-V, UV and XRD analysis. SEM images show very smooth and uniform CdTe nanowires freely standing on the substrate. The in-situ I-V characteristics of nano-/micro structures was carried out at room temperature by leaving the structures embedded in the insulating template membrane itself.

Optimized efficiency in InP nanowire solar cells with accurate 1D analysis

NASA Astrophysics Data System (ADS)

Chen, Yang; Kivisaari, Pyry; Pistol, Mats-Erik; Anttu, Nicklas

2018-01-01

Semiconductor nanowire arrays are a promising candidate for next generation solar cells due to enhanced absorption and reduced material consumption. However, to optimize their performance, time consuming three-dimensional (3D) opto-electronics modeling is usually performed. Here, we develop an accurate one-dimensional (1D) modeling method for the analysis. The 1D modeling is about 400 times faster than 3D modeling and allows direct application of concepts from planar pn-junctions on the analysis of nanowire solar cells. We show that the superposition principle can break down in InP nanowires due to strong surface recombination in the depletion region, giving rise to an IV-behavior similar to that with low shunt resistance. Importantly, we find that the open-circuit voltage of nanowire solar cells is typically limited by contact leakage. Therefore, to increase the efficiency, we have investigated the effect of high-bandgap GaP carrier-selective contact segments at the top and bottom of the InP nanowire and we find that GaP contact segments improve the solar cell efficiency. Next, we discuss the merit of p-i-n and p-n junction concepts in nanowire solar cells. With GaP carrier selective top and bottom contact segments in the InP nanowire array, we find that a p-n junction design is superior to a p-i-n junction design. We predict a best efficiency of 25% for a surface recombination velocity of 4500 cm s-1, corresponding to a non-radiative lifetime of 1 ns in p-n junction cells. The developed 1D model can be used for general modeling of axial p-n and p-i-n junctions in semiconductor nanowires. This includes also LED applications and we expect faster progress in device modeling using our method.

Optimized efficiency in InP nanowire solar cells with accurate 1D analysis.

PubMed

Chen, Yang; Kivisaari, Pyry; Pistol, Mats-Erik; Anttu, Nicklas

2018-01-26

Semiconductor nanowire arrays are a promising candidate for next generation solar cells due to enhanced absorption and reduced material consumption. However, to optimize their performance, time consuming three-dimensional (3D) opto-electronics modeling is usually performed. Here, we develop an accurate one-dimensional (1D) modeling method for the analysis. The 1D modeling is about 400 times faster than 3D modeling and allows direct application of concepts from planar pn-junctions on the analysis of nanowire solar cells. We show that the superposition principle can break down in InP nanowires due to strong surface recombination in the depletion region, giving rise to an IV-behavior similar to that with low shunt resistance. Importantly, we find that the open-circuit voltage of nanowire solar cells is typically limited by contact leakage. Therefore, to increase the efficiency, we have investigated the effect of high-bandgap GaP carrier-selective contact segments at the top and bottom of the InP nanowire and we find that GaP contact segments improve the solar cell efficiency. Next, we discuss the merit of p-i-n and p-n junction concepts in nanowire solar cells. With GaP carrier selective top and bottom contact segments in the InP nanowire array, we find that a p-n junction design is superior to a p-i-n junction design. We predict a best efficiency of 25% for a surface recombination velocity of 4500 cm s -1 , corresponding to a non-radiative lifetime of 1 ns in p-n junction cells. The developed 1D model can be used for general modeling of axial p-n and p-i-n junctions in semiconductor nanowires. This includes also LED applications and we expect faster progress in device modeling using our method.

The Mechanical Properties of Nanowires

PubMed Central

Wang, Shiliang; Shan, Zhiwei

2017-01-01

Applications of nanowires into future generation nanodevices require a complete understanding of the mechanical properties of the nanowires. A great research effort has been made in the past two decades to understand the deformation physics and mechanical behaviors of nanowires, and to interpret the discrepancies between experimental measurements and theoretical predictions. This review focused on the characterization and understanding of the mechanical properties of nanowires, including elasticity, plasticity, anelasticity and strength. As the results from the previous literature in this area appear inconsistent, a critical evaluation of the characterization techniques and methodologies were presented. In particular, the size effects of nanowires on the mechanical properties and their deformation mechanisms were discussed. PMID:28435775

Ultra compact triplexing filters based on SOI nanowire AWGs

NASA Astrophysics Data System (ADS)

Jiashun, Zhang; Junming, An; Lei, Zhao; Shijiao, Song; Liangliang, Wang; Jianguang, Li; Hongjie, Wang; Yuanda, Wu; Xiongwei, Hu

2011-04-01

An ultra compact triplexing filter was designed based on a silicon on insulator (SOI) nanowire arrayed waveguide grating (AWG) for fiber-to-the-home FTTH. The simulation results revealed that the design performed well in the sense of having a good triplexing function. The designed SOI nanowire AWGs were fabricated using ultraviolet lithography and induced coupler plasma etching. The experimental results showed that the crosstalk was less than -15 dB, and the 3 dB-bandwidth was 11.04 nm. The peak wavelength output from ports a, c, and b were 1455, 1510 and 1300 nm, respectively, which deviated from our original expectations. The deviation of the wavelength is mainly caused by 45 nm width deviation of the arrayed waveguides during the course of the fabrication process and partly caused by material dispersion.

Methods for synthesizing metal oxide nanowires

DOEpatents

Sunkara, Mahendra Kumar; Kumar, Vivekanand; Kim, Jeong H.; Clark, Ezra Lee

2016-08-09

A method of synthesizing a metal oxide nanowire includes the steps of: combining an amount of a transition metal or a transition metal oxide with an amount of an alkali metal compound to produce a mixture; activating a plasma discharge reactor to create a plasma discharge; exposing the mixture to the plasma discharge for a first predetermined time period such that transition metal oxide nanowires are formed; contacting the transition metal oxide nanowires with an acid solution such that an alkali metal ion is exchanged for a hydrogen ion on each of the transition metal oxide nanowires; and exposing the transition metal oxide nanowires to the plasma discharge for a second predetermined time period to thermally anneal the transition metal oxide nanowires. Transition metal oxide nanowires produced using the synthesis methods described herein are also provided.

One-dimensional nanostructures for novel biosensor and transparent electronics applications

NASA Astrophysics Data System (ADS)

Chang, Hsiao-Kang

This dissertation presents one-dimensional nanostructures for novel biosensors and transparent electronics applications. In chapter 1, background information regarding nanomaterials studied in this dissertation is described. In chapter 2, I describe the first application of antibody mimic proteins (AMPs) in the field of nanobiosensors. In2O3 nanowire based biosensors have been configured with an AMP (Fibronectin, Fn) to detect nucleocapsid (N) protein, a biomarker for severe acute respiratory syndrome (SARS). Using these devices, N protein was detected at sub-nanomolar concentration in the presence of 44 microM bovine serum albumin as a background. Furthermore, the binding constant of the AMP to Fn was determined from the concentration dependence of the response of our biosensors. In chapter 3, I demonstrate an In2O3 nanowire-based biosensing system that is capable of performing rapid, label-free, electrical detection of cancer biomarkers directly from human whole blood collected by a finger prick. Detection of multiple cancer biomarkers with high reliability at clinically meaningful concentrations from whole blood collected by a finger prick using this sensing system is demonstrated. In chapter 4, I introduce a top-down nanobiosensor based on polysilicon nanoribbon with enhanced yield and device uniformity. The polysilicon nanoribbon devices can be fabricated by conventional photolithography with only easily available materials and equipments required, thus results in great time and cost efficiency as well as scalability. The devices show great response to pH changes with a wide dynamic range and high sensitivity. Biomarker detection is also demonstrated with clinically relevant sensitivity. Such results suggest that polysilicon nanoribbon devices exhibit great potential toward a highly efficient, reliable and sensitive biosensing platform. In chapter 5, I demonstrate the first printed nanobiosensor application based on separated semiconducting single

Catalyst patterning for nanowire devices

NASA Technical Reports Server (NTRS)

Li, Jun (Inventor); Cassell, Alan M. (Inventor); Han, Jie (Inventor)

2004-01-01

Nanowire devices may be provided that are based on carbon nanotubes or single-crystal semiconductor nanowires. The nanowire devices may be formed on a substrate. Catalyst sites may be formed on the substrate. The catalyst sites may be formed using lithography, thin metal layers that form individual catalyst sites when heated, collapsible porous catalyst-filled microscopic spheres, microscopic spheres that serve as masks for catalyst deposition, electrochemical deposition techniques, and catalyst inks. Nanowires may be grown from the catalyst sites.

High resolution CMOS capacitance-frequency converter for biosensor applications

NASA Astrophysics Data System (ADS)

Ghoor, I. S.; Land, K.; Joubert, T.-H.

2016-02-01

This paper presents the design of a low-complexity, linear and sub-pF CMOS capacitance-frequency converter for reading out a capacitive bacterial bio/sensors with the endeavour of creating a universal bio/sensor readout module. Therefore the priority design objectives are a high resolution as well as an extensive dynamic range. The circuit is based on a method which outputs a digital frequency signal directly from a differential capacitance by the accumulation of charges produced by repetitive charge integration and charge preservation1. A prototype has been designed for manufacture in the 0.35 μm, 3.3V ams CMOS technology. At a 1MHz clock speed, the most pertinent results obtained for the designed converter are: (i) power consumption of 1.37mW; (ii) a resolution of at least 5 fF for sensitive capacitive transduction; and (iii) an input dynamic range of at least 43.5 dB from a measurable capacitance value range of 5 - 750 fF (iv) and a Pearson's coefficient of linearity of 0.99.

New Carrier Made from Glass Nanofibres for the Colorimetric Biosensor of Cholinesterase Inhibitors.

PubMed

Matějovský, Lukáš; Pitschmann, Vladimír

2018-05-30

Cholinesterase inhibitors are widely used as pesticides in agriculture, but also form a group of organophosphates known as nerve chemical warfare agents. This calls for close attention regarding their detection, including the use of various biosensors. One such biosensor made in the Czech Republic is the Detehit, which is based on a cholinesterase reaction that is assessed using a colour indicator-the Ellman's reagent-which is anchored on cellulose filter paper together with the substrate. With the use of this biosensor, detection is simple, quick, and sensitive. However, its disadvantage is that a less pronounced yellow discoloration occurs, especially under difficult light conditions. As a possible solution, a new indicator/substrate carrier has been designed. It is made of glass nanofibres, so the physical characteristics of the carrier positively influence reaction conditions, and as a result improve the colour response of the biosensor. The authors present and discuss some of the results of the study of this carrier under various experimental conditions. These findings have been used for the development of a modified Detehit biosensor.

Electrospun Fibro-porous Polyurethane Coatings for Implantable Glucose Biosensors

PubMed Central

Wang, Ning; Burugapalli, Krishna; Song, Wenhui; Halls, Justin; Moussy, Francis; Ray, Asim; Zheng, Yudong

2012-01-01

This study reports methods for coating miniature implantable glucose biosensors with electrospun polyurethane (PU) membranes, their effects on sensor function and efficacy as mass-transport limiting membranes. For electrospinning fibres directly on sensor surface, both static and dynamic collector systems, were designed and tested. Optimum collector configurations were first ascertained by FEA modelling. Both static and dynamic collectors allowed complete covering of sensors, but it was the dynamic collector that produced uniform fibro-porous PU coatings around miniature ellipsoid biosensors. The coatings had random fibre orientation and their uniform thickness increased linearly with increasing electrospinning time. The effects of coatings having an even spread of submicron fibre diameters and sub-100μm thicknesses on glucose biosensor function were investigated. Increasing thickness and fibre diameters caused a statistically insignificant decrease in sensor sensitivity for the tested electrospun coatings. The sensors’ linearity for the glucose detection range of 2 to 30mM remained unaffected. The electrospun coatings also functioned as mass-transport limiting membranes by significantly increasing the linearity, replacing traditional epoxy-PU outer coating. To conclude, electrospun coatings, having controllable fibro-porous structure and thicknesses, on miniature ellipsoid glucose biosensors were demonstrated to have minimal effect on pre-implantation sensitivity and also to have mass-transport limiting ability. PMID:23146433

Silicon nanowire arrays as thermoelectric material for a power microgenerator

NASA Astrophysics Data System (ADS)

Dávila, D.; Tarancón, A.; Fernández-Regúlez, M.; Calaza, C.; Salleras, M.; San Paulo, A.; Fonseca, L.

2011-10-01

A novel design of a silicon-based thermoelectric power microgenerator is presented in this work. Arrays of silicon nanowires, working as thermoelectric material, have been integrated in planar uni-leg thermocouple microstructures to convert waste heat into electrical energy. Homogeneous, uniformly dense, well-oriented and size-controlled arrays of silicon nanowires have been grown by chemical vapor deposition using the vapor-liquid-solid mechanism. Compatibility issues between the nanowire growth method and microfabrication techniques, such as electrical contact patterning, are discussed. Electrical measurements of the nanowire array electrical conductivity and the Seebeck voltage induced by a controlled thermal gradient or under harvesting operation mode have been carried out to demonstrate the feasibility of the microdevice. A resistance of 240 Ω at room temperature was measured for an array of silicon nanowires 10 µm -long, generating a Seebeck voltage of 80 mV under an imposed thermal gradient of 450 °C, whereas only 4.5 mV were generated under a harvesting operation mode. From the results presented, a Seebeck coefficient of about 150-190 µV K-1 was estimated, which corresponds to typical values for bulk silicon.

Fully Tunable Silicon Nanowire Arrays Fabricated by Soft Nanoparticle Templating.

PubMed

Rey, By Marcel; Elnathan, Roey; Ditcovski, Ran; Geisel, Karen; Zanini, Michele; Fernandez-Rodriguez, Miguel-Angel; Naik, Vikrant V; Frutiger, Andreas; Richtering, Walter; Ellenbogen, Tal; Voelcker, Nicolas H; Isa, Lucio

2016-01-13

We demonstrate a fabrication breakthrough to produce large-area arrays of vertically aligned silicon nanowires (VA-SiNWs) with full tunability of the geometry of the single nanowires and of the whole array, paving the way toward advanced programmable designs of nanowire platforms. At the core of our fabrication route, termed "Soft Nanoparticle Templating", is the conversion of gradually compressed self-assembled monolayers of soft nanoparticles (microgels) at a water-oil interface into customized lithographical masks to create VA-SiNW arrays by means of metal-assisted chemical etching (MACE). This combination of bottom-up and top-down techniques affords excellent control of nanowire etching site locations, enabling independent control of nanowire spacing, diameter and height in a single fabrication route. We demonstrate the fabrication of centimeter-scale two-dimensional gradient photonic crystals exhibiting continuously varying structural colors across the entire visible spectrum on a single silicon substrate, and the formation of tunable optical cavities supported by the VA-SiNWs, as unambiguously demonstrated through numerical simulations. Finally, Soft Nanoparticle Templating is combined with optical lithography to create hierarchical and programmable VA-SiNW patterns.

Electron Transport Properties of Ge nanowires

NASA Astrophysics Data System (ADS)

Hanrath, Tobias; Khondaker, Saiful I.; Yao, Zhen; Korgel, Brian A.

2003-03-01

Electron Transport Properties of Ge nanowires Tobias Hanrath*, Saiful I. Khondaker, Zhen Yao, Brian A. Korgel* *Dept. of Chemical Engineering, Dept. of Physics, Texas Materials Institute, and Center for Nano- and Molecular Science and Technology University of Texas at Austin, Austin, Texas 78712-1062 e-mail: korgel@mail.che.utexas.edu Germanium (Ge) nanowires with diameters ranging from 6 to 50 nm and several micrometer in length were grown via a supercritical fluid-liquid-solid synthesis. Parallel electron energy loss spectroscopy (PEELS) was employed to study the band structure and electron density in the Ge nanowires. The observed increase in plasmon peak energy and peak width with decreasing nanowire diameter is attributed to quantum confinement effects. For electrical characterization, Ge nanowires were deposited onto a patterned Si/SiO2 substrate. E-beam lithography was then used to form electrode contacts to individual nanowires. The influence of nanowire diameter, surface chemistry and crystallographic defects on electron transport properties were investigated and the comparison of Ge nanowire conductivity with respect to bulk, intrinsic Ge will be presented.

EDITORIAL: Nanowires for energy Nanowires for energy

NASA Astrophysics Data System (ADS)

LaPierre, Ray; Sunkara, Mahendra

2012-05-01

This special issue of Nanotechnology focuses on studies illustrating the application of nanowires for energy including solar cells, efficient lighting and water splitting. Over the next three decades, nanotechnology will make significant contributions towards meeting the increased energy needs of the planet, now known as the TeraWatt challenge. Nanowires in particular are poised to contribute significantly in this development as presented in the review by Hiralal et al [1]. Nanowires exhibit light trapping properties that can act as a broadband anti-reflection coating to enhance the efficiency of solar cells. In this issue, Li et al [2] and Wang et al [3] present the optical properties of silicon nanowire and nanocone arrays. In addition to enhanced optical properties, core-shell nanowires also have the potential for efficient charge carrier collection across the nanowire diameter as presented in the contribution by Yu et al [4] for radial junction a-Si solar cells. Hybrid approaches that combine organic and inorganic materials also have potential for high efficiency photovoltaics. A Si-based hybrid solar cell is presented by Zhang et al [5] with a photoconversion efficiency of over 7%. The quintessential example of hybrid solar cells is the dye-sensitized solar cell (DSSC) where an organic absorber (dye) coats an inorganic material (typically a ZnO nanostructure). Herman et al [6] present a method of enhancing the efficiency of a DSSC by increasing the hetero-interfacial area with a unique hierarchical weeping willow ZnO structure. The increased surface area allows for higher dye loading, light harvesting, and reduced charge recombination through direct conduction along the ZnO branches. Another unique ZnO growth method is presented by Calestani et al [7] using a solution-free and catalyst-free approach by pulsed electron deposition (PED). Nanowires can also make more efficient use of electrical power. Light emitting diodes, for example, will eventually become the

Programmable growth of branched silicon nanowires using a focused ion beam.

PubMed

Jun, Kimin; Jacobson, Joseph M

2010-08-11

Although significant progress has been made in being able to spatially define the position of material layers in vapor-liquid-solid (VLS) grown nanowires, less work has been carried out in deterministically defining the positions of nanowire branching points to facilitate more complicated structures beyond simple 1D wires. Work to date has focused on the growth of randomly branched nanowire structures. Here we develop a means for programmably designating nanowire branching points by means of focused ion beam-defined VLS catalytic points. This technique is repeatable without losing fidelity allowing multiple rounds of branching point definition followed by branch growth resulting in complex structures. The single crystal nature of this approach allows us to describe resulting structures with linear combinations of base vectors in three-dimensional (3D) space. Finally, by etching the resulting 3D defined wire structures branched nanotubes were fabricated with interconnected nanochannels inside. We believe that the techniques developed here should comprise a useful tool for extending linear VLS nanowire growth to generalized 3D wire structures.

Designing robust alumina nanowires-on-nanopores structures: superhydrophobic surfaces with slippery or sticky water adhesion.

PubMed

Peng, Shan; Tian, Dong; Miao, Xinrui; Yang, Xiaojun; Deng, Wenli

2013-11-01

Hierarchical alumina surfaces with different morphologies were fabricated by a simple one-step anodization method. These alumina films were fabricated by a new raw material: silica gel plate (aluminum foil with a low purity of 97.17%). The modulation of anodizing time enabled the formation of nanowires-on-nanopores hybrid nanostructures having controllable nanowires topographies through a self-assembly process. The resultant structures were demonstrated to be able to achieve superhydrophobicity without any hydrophobic coating layer. More interestingly, it is found that the as-prepared superhydrophobic alumina surfaces exhibited high contrast water adhesion. Hierarchical alumina film with nanowire bunches-on-nanopores (WBOP) morphology presents extremely slippery property which can obtain a sliding angle (SA) as low as 1°, nanowire pyramids-on-nanopores (WPOP) structure shows strongly sticky water adhesion with the adhesive ability to support 15 μL inverted water droplet at most. The obtained superhydrophobic alumina surfaces show remarkable mechanical durability even treated by crimping or pressing without impact on the water-repellent performance. Moreover, the created surfaces also show excellent resistivity to ice water, boiling water, high temperature, organic solvent and oil contamination, which could expand their usefulness and efficacy in harsh conditions. Copyright © 2013 Elsevier Inc. All rights reserved.

Monolithically Integrated Metal/Semiconductor Tunnel Junction Nanowire Light-Emitting Diodes.

PubMed

Sadaf, S M; Ra, Y H; Szkopek, T; Mi, Z

2016-02-10

We have demonstrated for the first time an n(++)-GaN/Al/p(++)-GaN backward diode, wherein an epitaxial Al layer serves as the tunnel junction. The resulting p-contact free InGaN/GaN nanowire light-emitting diodes (LEDs) exhibited a low turn-on voltage (∼2.9 V), reduced resistance, and enhanced power, compared to nanowire LEDs without the use of Al tunnel junction or with the incorporation of an n(++)-GaN/p(++)-GaN tunnel junction. This unique Al tunnel junction overcomes some of the critical issues related to conventional GaN-based tunnel junction designs, including stress relaxation, wide depletion region, and light absorption, and holds tremendous promise for realizing low-resistivity, high-brightness III-nitride nanowire LEDs in the visible and deep ultraviolet spectral range. Moreover, the demonstration of monolithic integration of metal and semiconductor nanowire heterojunctions provides a seamless platform for realizing a broad range of multifunctional nanoscale electronic and photonic devices.

Peptide–Nanowire Hybrid Materials for Selective Sensing of Small Molecules

PubMed Central

McAlpine, Michael C.; Agnew, Heather D.; Rohde, Rosemary D.; Blanco, Mario; Ahmad, Habib; Stuparu, Andreea D.; Goddard, William A.

2013-01-01

The development of a miniaturized sensing platform for the selective detection of chemical odorants could stimulate exciting scientific and technological opportunities. Oligopeptides are robust substrates for the selective recognition of a variety of chemical and biological species. Likewise, semiconducting nanowires are extremely sensitive gas sensors. Here we explore the possibilities and chemistries of linking peptides to silicon nanowire sensors for the selective detection of small molecules. The silica surface of the nanowires is passivated with peptides using amide coupling chemistry. The peptide/nanowire sensors can be designed, through the peptide sequence, to exhibit orthogonal responses to acetic acid and ammonia vapors, and can detect traces of these gases from “chemically camouflaged” mixtures. Through both theory and experiment, we find that this sensing selectivity arises from both acid/base reactivity and from molecular structure. These results provide a model platform for what can be achieved in terms of selective and sensitive “electronic noses.” PMID:18576642

A biosensor generated via high throughput screening quantifies cell edge Src dynamics

PubMed Central

Gulyani, Akash; Vitriol, Eric; Allen, Richard; Wu, Jianrong; Gremyachinskiy, Dmitriy; Lewis, Steven; Dewar, Brian; Graves, Lee M.; Kay, Brian K.; Kuhlman, Brian; Elston, Tim; Hahn, Klaus M.

2011-01-01

Fluorescent biosensors for living cells currently require laborious optimization and a unique design for each target. They are limited by the availability of naturally occurring ligands with appropriate target specificity. Here we describe a biosensor based on an engineered fibronectin monobody scaffold that can be tailored to bind different targets via high throughput screening. This Src family kinase (SFK) biosensor was made by derivatizing a monobody specific for activated SFK with a bright dye whose fluorescence increases upon target binding. We identified sites for dye attachment and alterations to eliminate vesiculation in living cells, providing a generalizable scaffold for biosensor production. This approach minimizes cell perturbation because it senses endogenous, unmodified target, and because sensitivity is enhanced by direct dye excitation. Automated correlation of cell velocities and SFK activity revealed that SFK are activated specifically during protrusion. Activity correlates with velocity, and peaks 1–2 microns from the leading edge. PMID:21666688

Tailoring light-matter coupling in semiconductor and hybrid-plasmonic nanowires

PubMed Central

Piccione, Brian; Aspetti, Carlos O.; Cho, Chang-Hee; Agarwal, Ritesh

2014-01-01

Understanding interactions between light and matter is central to many fields, providing invaluable insights into the nature of matter. In its own right, a greater understanding of light-matter coupling has allowed for the creation of tailored applications, resulting in a variety of devices such as lasers, switches, sensors, modulators, and detectors. Reduction of optical mode volume is crucial to enhancing light-matter coupling strength, and among solid-state systems, self-assembled semiconductor and hybrid-plasmonic nanowires are amenable to creation of highly-confined optical modes. Following development of unique spectroscopic techniques designed for the nanowire morphology, carefully engineered semiconductor nanowire cavities have recently been tailored to enhance light-matter coupling strength in a manner previously seen in optical microcavities. Much smaller mode volumes in tailored hybrid-plasmonic nanowires have recently allowed for similar breakthroughs, resulting in sub-picosecond excited-state lifetimes and exceptionally high radiative rate enhancement. Here, we review literature on light-matter interactions in semiconductor and hybrid-plasmonic monolithic nanowire optical cavities to highlight recent progress made in tailoring light-matter coupling strengths. Beginning with a discussion of relevant concepts from optical physics, we will discuss how our knowledge of light-matter coupling has evolved with our ability to produce ever-shrinking optical mode volumes, shifting focus from bulk materials to optical microcavities, before moving on to recent results obtained from semiconducting nanowires. PMID:25093385

Application of bioconjugation chemistry on biosensor fabrication for detection of TAR-DNA binding protein 43.

PubMed

Dai, Yifan; Wang, Chunlai; Chiu, Liang-Yuan; Abbasi, Kevin; Tolbert, Blanton S; Sauvé, Geneviève; Yen, Yun; Liu, Chung-Chiun

2018-06-01

A simple-prepare, single-use and cost-effective, in vitro biosensor for the detection of TAR DNA-binding protein 43 (TDP-43), a biomarker of neuro-degenerative disorders, was designed, manufactured and tested. This study reports the first biosensor application for the detection of TDP-43 using a novel biosensor fabrication methodology. Bioconjugation mechanism was applied by conjugating anti-TDP 43 with N-succinimidyl S-acetylthioacetate (SATA) producing a thiol-linked anti-TDP 43, which was used to directly link with gold electrode surface, minimizing the preparation steps for biosensor fabrication and simplifying the biosensor surface. The effectiveness of this bioconjugation mechanism was evaluated and confirmed by FqRRM12 protein, using nuclear magnetic resonance (NMR). The surface coverage of the electrode was analyzed by Time-of-Flight-Secondary Ion Mass Spectrometry (TOF-SIMS). Differential pulse voltammetry (DPV) was acted as the detection transduction mechanism with the use of [Fe(CN) 6 ] 3-/4- redox probe. Human TDP-43 peptide of 0.0005 µg/mL to 2 µg/mL in undiluted human serum was analyzed using this TDP-43 biosensor. Interference study of the TDP-43 biosensor using β-amyloid 42 protein and T-tau protein confirmed the specificity of this TDP-43 biosensor. This bioconjugation chemistry based approach for biosensor fabrication circumvents tedious gold surface modification and functionalization while enabling specific detection of TDP-43 in less than 1 h with a low fabrication cost of a single biosensor less than $3. Copyright © 2018 Elsevier B.V. All rights reserved.

Development and testing of a fluorescence biosensor for glucose sensing

NASA Astrophysics Data System (ADS)

Aloraefy, Mamdouh; Pfefer, Joshua; Ramella-Roman, Jessica; Sapsford, Kim

2012-06-01

Rapid, accurate, and minimally-invasive biosensors for glucose measurement have the potential to enhance management of diabetes mellitus and improve patient outcome in intensive care settings. Recent studies have indicated that implantable biosensors based on Förster Resonance Energy Transfer (FRET) can provide high sensitivity in quantifying glucose concentrations. However, standard approaches for determining the potential for interference from other biological constituents have not been established. The aim of this work was to design and optimize a FRET-based glucose sensor and assess its specificity to glucose. A sensor based on competitive binding between concanavalin A and dextran, labeled with long-wavelength acceptor and donor fluorophores, was developed. This process included optimization of dextran molecular weight and donor concentration, acceptor to donor ratio, and hydrogel concentration, as well as the number of polymer layers for encapsulation. The biosensor performance was characterized in terms of its response to clinically relevant glucose concentrations. The potential for interference and the development of test methods to evaluate this effect were studied using a potential clinical interferent, maltose. Results indicated that our biosensor had a prediction accuracy of better than 11% and that the robustness to maltose was highly dependent on glucose level.

Detection of miRNA using a double-strand displacement biosensor with a self-complementary fluorescent reporter.

PubMed

Larkey, Nicholas E; Almlie, C Kyle; Tran, Victoria; Egan, Marianne; Burrows, Sean M

2014-02-04

Design of rapid, selective, and sensitive DNA and ribonucleic acid (RNA) biosensors capable of minimizing false positives from nuclease degradation is crucial for translational research and clinical diagnostics. We present proof-of-principle studies of an innovative micro-ribonucleic acid (miRNA) reporter-probe biosensor that displaces a self-complementary reporter, while target miRNA binds to the probe. The freed reporter folds into a hairpin structure to induce a decrease in the fluorescent signal. The self-complementarity of the reporter facilitates the reduction of false positives from nuclease degradation. Nanomolar limits of detection and quantitation were capable with this proof-of-principle design. Detection of miRNA occurs within 10 min and does not require any additional hybridization, labeling, or rinsing steps. The potential for medical applications of the reporter-probe biosensor is demonstrated by selective detection of a cancer regulating microRNA, Lethal-7 (Let-7a). Mechanisms for transporting the biosensor across the cell membrane will be the focus of future work.

ZnO-nanorods/graphene heterostructure: a direct electron transfer glucose biosensor

NASA Astrophysics Data System (ADS)

Zhao, Yu; Li, Wenbo; Pan, Lijia; Zhai, Dongyuan; Wang, Yu; Li, Lanlan; Cheng, Wen; Yin, Wei; Wang, Xinran; Xu, Jian-Bin; Shi, Yi

2016-08-01

ZnO-nanorods/graphene heterostructure was synthesized by hydrothermal growth of ZnO nanorods on chemically reduced graphene (CRG) film. The hybrid structure was demonstrated as a biosensor, where direct electron transfer between glucose oxidase (GOD) and electrode was observed. The charge transfer was attributed to the ZnO nanorod wiring between the redox center of GOD and electrode, and the ZnO/graphene heterostructure facilitated the transport of electrons on the hybride electrode. The glucose sensor based on the GOD-ZnO/CRG/Pt electrode had a high sensitivity of 17.64 μA mM-1, which is higher than most of the previously reported values for direct electron transfer based glucose biosensors. Moreover, this biosensor is linearly proportional to the concentration of glucose in the range of 0.2-1.6 mM. The study revealed that the band structure of electrode could affect the detection of direct electron transfer of GOD, which would be helpful for the design of the biosensor electrodes in the future.

ZnO-nanorods/graphene heterostructure: a direct electron transfer glucose biosensor

PubMed Central

Zhao, Yu; Li, Wenbo; Pan, Lijia; Zhai, Dongyuan; Wang, Yu; Li, Lanlan; Cheng, Wen; Yin, Wei; Wang, Xinran; Xu, Jian-Bin; Shi, Yi

2016-01-01

ZnO-nanorods/graphene heterostructure was synthesized by hydrothermal growth of ZnO nanorods on chemically reduced graphene (CRG) film. The hybrid structure was demonstrated as a biosensor, where direct electron transfer between glucose oxidase (GOD) and electrode was observed. The charge transfer was attributed to the ZnO nanorod wiring between the redox center of GOD and electrode, and the ZnO/graphene heterostructure facilitated the transport of electrons on the hybride electrode. The glucose sensor based on the GOD-ZnO/CRG/Pt electrode had a high sensitivity of 17.64 μA mM−1, which is higher than most of the previously reported values for direct electron transfer based glucose biosensors. Moreover, this biosensor is linearly proportional to the concentration of glucose in the range of 0.2–1.6 mM. The study revealed that the band structure of electrode could affect the detection of direct electron transfer of GOD, which would be helpful for the design of the biosensor electrodes in the future. PMID:27572675

Advanced biosensors for monitoring astronauts' health during long-duration space missions.

PubMed

Roda, Aldo; Mirasoli, Mara; Guardigli, Massimo; Zangheri, Martina; Caliceti, Cristiana; Calabria, Donato; Simoni, Patrizia

2018-07-15

Long-duration space missions pose important health concerns for astronauts, especially regarding the adverse effects of microgravity and exposure to high-energy cosmic rays. The long-term maintenance of crew health and performance mainly relies on prevention, early diagnoses, condition management, and medical interventions in situ. In-flight biosensor diagnostic devices and medical procedures must use few resources and operate in a microgravity environment, which complicates the collection and management of biological samples. Moreover, the biosensors must be certified for in-flight operation according to strict design and safety regulations. Herein, we report on the state of the art and recent advances in biosensing diagnostic instrumentation for monitoring astronauts' health during long-duration space missions, including portable and wearable biosensors. We discuss perspectives on new-format biosensors in autonomous space clinics. We also describe our own work in developing biosensing devices for non-invasively diagnosing space-related diseases, and how they are used in long-duration missions. Finally, we discuss the benefits of space exploration for Earth-based medicine. Copyright © 2018 Elsevier B.V. All rights reserved.

Plasmonic Nanowires for Wide Wavelength Range Molecular Sensing.

PubMed

Marinaro, Giovanni; Das, Gobind; Giugni, Andrea; Allione, Marco; Torre, Bruno; Candeloro, Patrizio; Kosel, Jurgen; Di Fabrizio, Enzo

2018-05-17

In this paper, we propose the use of a standing nanowires array, constituted by plasmonic active gold wires grown on iron disks, and partially immersed in a supporting alumina matrix, for surface-enhanced Raman spectroscopy applications. The galvanic process was used to fabricate nanowires in pores of anodized alumina template, making this device cost-effective. This fabrication method allows for the selection of size, diameter, and spatial arrangement of nanowires. The proposed device, thanks to a detailed design analysis, demonstrates a broadband plasmonic enhancement effect useful for many standard excitation wavelengths in the visible and NIR. The trigonal pores arrangement gives an efficiency weakly dependent on polarization. The devices, tested with 633 and 830 nm laser lines, show a significant Raman enhancement factor, up to around 6 × 10⁴, with respect to the flat gold surface, used as a reference for the measurements of the investigated molecules.

Biosensoric potential of microbial fuel cells.

PubMed

Schneider, György; Kovács, Tamás; Rákhely, Gábor; Czeller, Miklós

2016-08-01

Recent progress in microbial fuel cell (MFC) technology has highlighted the potential of these devices to be used as biosensors. The advantages of MFC-based biosensors are that they are phenotypic and can function in either assay- or flow-through formats. These features make them appropriate for contiguous on-line monitoring in laboratories and for in-field applications. The selectivity of an MFC biosensor depends on the applied microorganisms in the anodic compartment where electron transfer (ET) between the artificial surface (anode) and bacterium occurs. This process strongly determines the internal resistance of the sensoric system and thus influences signal outcome and response time. Despite their beneficial characteristics, the number of MFC-based biosensoric applications has been limited until now. The aim of this mini-review is to turn attention to the biosensoric potential of MFCs by summarizing ET mechanisms on which recently established and future sensoric devices are based.

Electrically Injected UV-Visible Nanowire Lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, George T.; Li, Changyi; Li, Qiming

2015-09-01

There is strong interest in minimizing the volume of lasers to enable ultracompact, low-power, coherent light sources. Nanowires represent an ideal candidate for such nanolasers as stand-alone optical cavities and gain media, and optically pumped nanowire lasing has been demonstrated in several semiconductor systems. Electrically injected nanowire lasers are needed to realize actual working devices but have been elusive due to limitations of current methods to address the requirement for nanowire device heterostructures with high material quality, controlled doping and geometry, low optical loss, and efficient carrier injection. In this project we proposed to demonstrate electrically injected single nanowire lasersmore » emitting in the important UV to visible wavelengths. Our approach to simultaneously address these challenges is based on high quality III-nitride nanowire device heterostructures with precisely controlled geometries and strong gain and mode confinement to minimize lasing thresholds, enabled by a unique top-down nanowire fabrication technique.« less

Live-cell MRI with xenon hyper-CEST biosensors targeted to metabolically labeled cell-surface glycans.

PubMed

Witte, Christopher; Martos, Vera; Rose, Honor May; Reinke, Stefan; Klippel, Stefan; Schröder, Leif; Hackenberger, Christian P R

2015-02-23

The targeting of metabolically labeled glycans with conventional MRI contrast agents has proved elusive. In this work, which further expands the utility of xenon Hyper-CEST biosensors in cell experiments, we present the first successful molecular imaging of such glycans using MRI. Xenon Hyper-CEST biosensors are a novel class of MRI contrast agents with very high sensitivity. We designed a multimodal biosensor for both fluorescent and xenon MRI detection that is targeted to metabolically labeled sialic acid through bioorthogonal chemistry. Through the use of a state of the art live-cell bioreactor, it was demonstrated that xenon MRI biosensors can be used to image cell-surface glycans at nanomolar concentrations. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Vertically Aligned Carbon Nanofiber based Biosensor Platform for Glucose Sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al Mamun, Khandaker A.; Tulip, Fahmida S.; MacArthur, Kimberly

2014-03-01

Vertically aligned carbon nanofibers (VACNFs) have recently become an important tool for biosensor design. Carbon nanofibers (CNF) have excellent conductive and structural properties with many irregularities and defect sites in addition to exposed carboxyl groups throughout their surfaces. These properties allow a better immobilization matrix compared to carbon nanotubes and offer better resolution when compared with the FET-based biosensors. VACNFs can be deterministically grown on silicon substrates allowing optimization of the structures for various biosensor applications. Two VACNF electrode architectures have been employed in this study and a comparison of their performances has been made in terms of sensitivity, sensingmore » limitations, dynamic range, and response time. The usage of VACNF platform as a glucose sensor has been verified in this study by selecting an optimum architecture based on the VACNF forest density. Read More: http://www.worldscientific.com/doi/abs/10.1142/S0129156414500062« less

Development of electrochemical biosensors with various types of zeolites

NASA Astrophysics Data System (ADS)

Soldatkina, O. V.; Kucherenko, I. S.; Soldatkin, O. O.; Pyeshkova, V. M.; Dudchenko, O. Y.; Akata Kurç, B.; Dzyadevych, S. V.

2018-03-01

In the work, different types of zeolites were used for the development of enzyme-based electrochemical biosensors. Zeolites were added to the biorecognition elements of the biosensors and served as additional components of the biomembranes or adsorbents for enzymes. Three types of biosensors (conductometric, amperometric and potentiometric) were studied. The developed biosensors were compared with the similar biosensors without zeolites. The biosensors contained the following enzymes: urease, glucose oxidase, glutamate oxidase, and acetylcholinesterase and were intended for the detection of urea, glucose, glutamate, and acetylcholine, respectively. Construction of the biosensors using the adsorption of enzymes on zeolites has several advantages: simplicity, good reproducibility, quickness, absence of toxic compounds. These benefits are particularly important for the standardization and further mass production of the biosensors. Furthermore, a biosensor for the sucrose determination contained a three-enzyme system (invertase/mutatorase/glucose oxidase), immobilized by a combination of adsorption on silicalite and cross-linking via glutaraldehyde; such combined immobilization demonstrated better results as compared with adsorption or cross-linking separately. The analysis of urea and sucrose concentrations in the real samples was carried out. The results, obtained with biosensors, had high correlation with the results of traditional analytical methods, thus the developed biosensors are promising for practical applications.

Current status of water environment and their microbial biosensor techniques - Part II: Recent trends in microbial biosensor development.

PubMed

Nakamura, Hideaki

2018-05-08

In Part I of the present review series, I presented the current state of the water environment by focusing on Japanese cases and discussed the need to further develop microbial biosensor technologies for the actual water environment. I comprehensively present trends after approximately 2010 in microbial biosensor development for the water environment. In the first section, after briefly summarizing historical studies, recent studies on microbial biosensor principles are introduced. In the second section, recent application studies for the water environment are also introduced. Finally, I conclude the present review series by describing the need to further develop microbial biosensor technologies. Graphical abstract Current water pollution indirectly occurs by anthropogenic eutrophication (Part I). Recent trends in microbial biosensor development for water environment are described in part II of the present review series.

Conductance of kinked nanowires

NASA Astrophysics Data System (ADS)

Cook, B. G.; Varga, K.

2011-01-01

The conductance properties of kinked nanowires are studied by first-principles transport calculations within a recently developed complex potential framework. Using prototypical examples of monoatomic Au chains as well as small diameter single-crystalline silicon nanowires we show that transmission strongly depends on the kink geometry and one can tune the conductance properties by the kink angle and other geometrical factors. In the case of a silicon nanowire the presence of a kink drastically reduces the conductance.

Controlling the plasmonic surface waves of metallic nanowires by transformation optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Yichao; Yuan, Jun; Yin, Ge

2015-07-06

In this letter, we introduce the technique of using transformation optics to manipulate the mode states of surface plasmonic waves of metallic nanowire waveguides. As examples we apply this technique to design two optical components: a three-dimensional (3D) electromagnetic mode rotator and a mode convertor. The rotator can rotate the polarization state of the surface wave around plasmonic nanowires by arbitrarily desired angles, and the convertor can transform the surface wave modes from one to another. Full-wave simulation is performed to verify the design and efficiency of our devices. Their potential application in photonic circuits is envisioned.

Mechanisms involved in the hydrothermal growth of ultra-thin and high aspect ratio ZnO nanowires

NASA Astrophysics Data System (ADS)

Demes, Thomas; Ternon, Céline; Morisot, Fanny; Riassetto, David; Legallais, Maxime; Roussel, Hervé; Langlet, Michel

2017-07-01

Hydrothermal synthesis of ZnO nanowires (NWs) with tailored dimensions, notably high aspect ratios (AR) and small diameters, is a major concern for a wide range of applications and still represents a challenging and recurring issue. In this work, an additive-free and reproducible hydrothermal procedure has been developed to grow ultra-thin and high AR ZnO NWs on sol-gel deposited ZnO seed layers. Controlling the substrate temperature and using a low reagent concentration (1 mM) has been found to be essential for obtaining such NWs. We show that the NW diameter remains constant at about 20-25 nm with growth time contrary to the NW length that can be selectively increased leading to NWs with ARs up to 400. On the basis of investigated experimental conditions along with thermodynamic and kinetic considerations, a ZnO NW growth mechanism has been developed which involves the formation and growth of nuclei followed by NW growth when the nuclei reach a critical size of about 20-25 nm. The low reagent concentration inhibits NW lateral growth leading to ultra-thin and high AR NWs. These NWs have been assembled into electrically conductive ZnO nanowire networks, which opens attractive perspectives toward the development of highly sensitive low-cost gas- or bio-sensors.

PREFACE: Synthesis and integration of nanowires

NASA Astrophysics Data System (ADS)

Samuelson, L.

2006-06-01

The field of semiconductor nanowires has attracted much attention in recent years, from the areas of basic materials science, advanced characterization and technology, as well as from the perspective of the applications of nanowires. Research on large-sized whiskers and wires had already begun in the 1960s with the pioneering work of Wagner, as well as by other researchers. It was, however, in the early 1990s that Kenji Hiruma at Hitachi Central Research Laboratories in Japan first succeeded in developing methods for the growth of nanowires with dimensions on the scale of 10-100 nm, thereby initiating the field of growth and applications of nanowires, with a strong emphasis on epitaxial nucleation of nanowires on a single-crystalline substrate. Starting from the mid-1990s, the field developed very rapidly with the number of papers on the subject growing from ten per year to several thousand papers on the subject published annually today, although with a rather generous definition of the concept of nanowires. With this rapid development we have seen many new and different approaches to the growth of nanowires, technological advances leading to a more well-controlled formation of nanowires, new innovative methods for the characterization of structures, as well as a wealth of approaches towards the use of nanowires in electronics, photonics and sensor applications. This issue contains contributions from many different laboratories, each adding significant detail to the development of the field of research. The contributions cover issues such as basic growth, advanced characterization and technology, and application of nanowires. I would like to acknowledge the shared responsibilities for this special issue of Nanotechnology on the synthesis and integration of nanowires with my co-Editors, S Tong Lee and M Sunkara, as well as the highly professional support from Dr Nina Couzin, Dr Ian Forbes and the Nanotechnology team from the Institute of Physics Publishing.

Transport properties of Sb-doped Si nanowires

NASA Astrophysics Data System (ADS)

Nukala, Prathyusha; Sapkota, Gopal; Gali, Pradeep; Philipose, U.

2012-08-01

We present a safe and cost-effective approach for synthesis of n-type Sb-doped Si nanowires. The nanowires were synthesized at ambient pressure using SiCl4 as Si source and pure Sb as the dopant source. Structural and compositional characterization using electron microscopy and X-ray spectroscopy show crystalline nanowires with lengths of 30-40 μm and diameters of 40-100 nm. A 3-4 nm thick amorphous oxide shell covers the surface of the nanowire, post-growth. The composition of this shell was confirmed by Raman spectroscopy. Growth of Si nanowires, followed by low temperature annealing in Sb vapor, was shown to be an effective technique for synthesizing Sb-doped Si nanowires. The doping concentration of Sb was found to be dependent on temperature, with Sb re-evaporating from the Si nanowire at higher doping temperatures. Field effect transistors (FETs) were fabricated to investigate the electrical transport properties of these nanowires. The as-grown Si nanowires were found to be p-type with a channel mobility of 40 cm2 V-1 s-1. After doping with Sb, these nanowires exhibited n-type behavior. The channel mobility and carrier concentration of the Sb-doped Si nanowires were estimated to be 288 cm2 V-1 s-1 and 5.3×1018 cm-3 respectively.

Triggered optical biosensor

DOEpatents

Song, Xuedong; Swanson, Basil I.

2001-10-02

An optical biosensor is provided for the detection of a multivalent target biomolecule, the biosensor including a substrate having a bilayer membrane thereon, a recognition molecule situated at the surface, the recognition molecule capable of binding with the multivalent target biomolecule, the recognition molecule further characterized as including a fluorescence label thereon and as being movable at the surface and a device for measuring a fluorescence change in response to binding between the recognition molecule and the multivalent target biomolecule.

Controllable High-Speed Rotation of Nanowires

NASA Astrophysics Data System (ADS)

Fan, D. L.; Zhu, F. Q.; Cammarata, R. C.; Chien, C. L.

2005-06-01

We report a versatile method for executing controllable high-speed rotation of nanowires by ac voltages applied to multiple electrodes. The rotation of the nanowires can be instantly switched on or off with precisely controlled rotation speed (to at least 1800 rpm), definite chirality, and total angle of rotation. We have determined the torque due to the fluidic drag force on nanowire of different lengths. We also demonstrate a micromotor using a rotating nanowire driving a dust particle into circular motion. This method has been used to rotate magnetic and nonmagnetic nanowires as well as carbon nanotubes.

Carbohydrate-based electrochemical biosensor for detection of a cancer biomarker in human plasma.

PubMed

Devillers, Marion; Ahmad, Lama; Korri-Youssoufi, Hafsa; Salmon, Laurent

2017-10-15

Autocrine motility factor (AMF) is a tumor-secreted cytokine that stimulates tumor cell motility in vitro and metastasis in vivo. AMF could be detected in serum or urine of cancer patients with worse prognosis. Reported as a cancer biomarker, AMF secretion into body fluids might be closely related to metastases formation. In this study, a sensitive and specific carbohydrate-based electrochemical biosensor was designed for the detection and quantification of a protein model of AMF, namely phosphoglucose isomerase from rabbit muscle (RmPGI). Indeed, RmPGI displays high homology with AMF and has been shown to have AMF activity. The biosensor was constructed by covalent binding of the enzyme substrate d-fructose 6-phosphate (F6P). Immobilization was achieved on a gold surface electrode following a bottom-up approach through an aminated surface obtained by electrochemical patterning of ethylene diamine and terminal amine polyethylene glycol chain to prevent non-specific interactions. Carbohydrate-protein interactions were quantified in a range of 10 fM to 100nM. Complex formation was analyzed through monitoring of the redox couple Fe 2+ /Fe 3+ by electrochemical impedance spectroscopy and square wave voltammetry. The F6P-biosensor demonstrates a detection limit of 6.6 fM and high selectivity when compared to other non-specific glycolytic proteins such as d-glucose-6-phosphate dehydrogenase. Detection of protein in spiked plasma was demonstrated and accuracy of 95% is obtained compared to result obtained in PBS (phosphate buffered saline). F6P-biosensor is a very promising proof of concept required for the design of a carbohydrate-based electrochemical biosensor using the enzyme substrate as bioreceptor. Such biosensor could be generalized to detect other protein biomarkers of interest. Copyright © 2017 Elsevier B.V. All rights reserved.

Hierarchically structured Co₃O₄@Pt@MnO₂ nanowire arrays for high-performance supercapacitors.

PubMed

Xia, Hui; Zhu, Dongdong; Luo, Zhentao; Yu, Yue; Shi, Xiaoqin; Yuan, Guoliang; Xie, Jianping

2013-10-17

Here we proposed a novel architectural design of a ternary MnO2-based electrode - a hierarchical Co3O4@Pt@MnO2 core-shell-shell structure, where the complemental features of the three key components (a well-defined Co3O4 nanowire array on the conductive Ti substrate, an ultrathin layer of small Pt nanoparticles, and a thin layer of MnO2 nanoflakes) are strategically combined into a single entity to synergize and construct a high-performance electrode for supercapacitors. Owing to the high conductivity of the well-defined Co3O4 nanowire arrays, in which the conductivity was further enhanced by a thin metal (Pt) coating layer, in combination with the large surface area provided by the small MnO2 nanoflakes, the as-fabricated Co3O4@Pt@MnO2 nanowire arrays have exhibited high specific capacitances, good rate capability, and excellent cycling stability. The architectural design demonstrated in this study provides a new approach to fabricate high-performance MnO2-based nanowire arrays for constructing next-generation supercapacitors.

Development of an acoustic wave based biosensor for vapor phase detection of small molecules

NASA Astrophysics Data System (ADS)

Stubbs, Desmond

For centuries scientific ingenuity and innovation have been influenced by Mother Nature's perfect design. One of her more elusive designs is that of the sensory olfactory system, an array of highly sensitive receptors responsible for chemical vapor recognition. In the animal kingdom this ability is magnified among canines where ppt (parts per trillion) sensitivity values have been reported. Today, detection dogs are considered an essential part of the US drug and explosives detection schemes. However, growing concerns about their susceptibility to extraneous odors have inspired the development of highly sensitive analytical detection tools or biosensors known as "electronic noses". In general, biosensors are distinguished from chemical sensors in that they use an entity of biological origin (e.g. antibody, cell, enzyme) immobilized onto a surface as the chemically-sensitive film on the device. The colloquial view is that the term "biosensors" refers to devices which detect the presence of entities of biological origin, such as proteins or single-stranded DNA and that this detection must take place in a liquid. Our biosensor utilizes biomolecules, specifically IgG monoclonal antibodies, to achieve molecular recognition of relatively small molecules in the vapor phase.

Nanowire growth and sublimation: CdTe quantum dots in ZnTe nanowires

NASA Astrophysics Data System (ADS)

Orrù, M.; Robin, E.; Den Hertog, M.; Moratis, K.; Genuist, Y.; André, R.; Ferrand, D.; Cibert, J.; Bellet-Amalric, E.

2018-04-01

The role of the sublimation of the compound and of the evaporation of the constituents from the gold nanoparticle during the growth of semiconductor nanowires is exemplified with CdTe-ZnTe heterostructures. Operating close to the upper temperature limit strongly reduces the amount of Cd present in the gold nanoparticle and the density of adatoms on the nanowire sidewalls. As a result, the growth rate is small and strongly temperature dependent, but a good control of the growth conditions allows the incorporation of quantum dots in nanowires with sharp interfaces and adjustable shape, and it minimizes the radial growth and the subsequent formation of additional CdTe clusters on the nanowire sidewalls, as confirmed by photoluminescence. Uncapped CdTe segments dissolve into the gold nanoparticle when interrupting the flux, giving rise to a bulblike (pendant-droplet) shape attributed to the Kirkendall effect.

Nanomaterial-Based Electrochemical Biosensors and Bioassays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Guodong; Mao, Xun; Gurung, Anant

2010-08-31

This book chapter summarizes the recent advance in nanomaterials for electrochemical biosensors and bioassays. Biofunctionalization of nanomaterials for biosensors fabrication and their biomedical applications are discussed.

Enhancement in sensitivity of graphene-based zinc oxide assisted bimetallic surface plasmon resonance (SPR) biosensor

NASA Astrophysics Data System (ADS)

Kumar, Rajeev; Kushwaha, Angad S.; Srivastava, Monika; Mishra, H.; Srivastava, S. K.

2018-03-01

In the present communication, a highly sensitive surface plasmon resonance (SPR) biosensor with Kretschmann configuration having alternate layers, prism/zinc oxide/silver/gold/graphene/biomolecules (ss-DNA) is presented. The optimization of the proposed configuration has been accomplished by keeping the constant thickness of zinc oxide (32 nm), silver (32 nm), graphene (0.34 nm) layer and biomolecules (100 nm) for different values of gold layer thickness (1, 3 and 5 nm). The sensitivity of the proposed SPR biosensor has been demonstrated for a number of design parameters such as gold layer thickness, number of graphene layer, refractive index of biomolecules and the thickness of biomolecules layer. SPR biosensor with optimized geometry has greater sensitivity (66 deg/RIU) than the conventional (52 deg/RIU) as well as other graphene-based (53.2 deg/RIU) SPR biosensor. The effect of zinc oxide layer thickness on the sensitivity of SPR biosensor has also been analysed. From the analysis, it is found that the sensitivity increases significantly by increasing the thickness of zinc oxide layer. It means zinc oxide intermediate layer plays an important role to improve the sensitivity of the biosensor. The sensitivity of SPR biosensor also increases by increasing the number of graphene layer (upto nine layer).

Synthetic Electric Microbial Biosensors

DTIC Science & Technology

2017-06-10

In particular, monitoring of heavy metals in the environment, drinking water, food , and biological fluids is of interest. Conventional techniques...instances of contamination , and the potential for deliberate spills, interest has grown in portable devices for onsite long-term detection using sensor...biosensor systems for the online detection of a range of contaminants . Synthetic Biology and biosensors Synthetic biology has gained much interest

High-Quality In-Plane Aligned CsPbX3 Perovskite Nanowire Lasers with Composition-Dependent Strong Exciton-Photon Coupling.

PubMed

Wang, Xiaoxia; Shoaib, Muhammad; Wang, Xiao; Zhang, Xuehong; He, Mai; Luo, Ziyu; Zheng, Weihao; Li, Honglai; Yang, Tiefeng; Zhu, Xiaoli; Ma, Libo; Pan, Anlian

2018-06-14

Cesium lead halide perovskite nanowires have emerged as promising low-dimensional semiconductor structures for integrated photonic applications. Understanding light-matter interactions in a nanowire cavity is of both fundamental and practical interest in designing low-power-consumption nanoscale light sources. In this work, high-quality in-plane aligned halide perovskite CsPbX 3 (X = Cl, Br, I) nanowires are synthesized by a vapor growth method on an annealed M-plane sapphire substrate. Large-area nanowire laser arrays have been achieved based on the as-grown aligned CsPbX 3 nanowires at room temperature with quite low pumping thresholds, very high quality factors, and a high degree of linear polarization. More importantly, it is found that exciton-polaritons are formed in the nanowires under the excitation of a pulsed laser, indicating a strong exciton-photon coupling in the optical microcavities made of cesium lead halide perovskites. The coupling strength in these CsPbX 3 nanowires is dependent on the atomic composition, where the obtained room-temperature Rabi splitting energy is ∼210 ± 13, 146 ± 9, and 103 ± 5 meV for the CsPbCl 3 , CsPbBr 3 , and CsPbI 3 nanowires, respectively. This work provides fundamental insights for the practical applications of all-inorganic perovskite CsPbX 3 nanowires in designing light-emitting devices and integrated nanophotonic systems.

Ultrathin Au-Alloy Nanowires at the Liquid-Liquid Interface.

PubMed

Chatterjee, Dipanwita; Shetty, Shwetha; Müller-Caspary, Knut; Grieb, Tim; Krause, Florian F; Schowalter, Marco; Rosenauer, Andreas; Ravishankar, Narayanan

2018-03-14

Ultrathin bimetallic nanowires are of importance and interest for applications in electronic devices such as sensors and heterogeneous catalysts. In this work, we have designed a new, highly reproducible and generalized wet chemical method to synthesize uniform and monodispersed Au-based alloy (AuCu, AuPd, and AuPt) nanowires with tunable composition using microwave-assisted reduction at the liquid-liquid interface. These ultrathin alloy nanowires are below 4 nm in diameter and about 2 μm long. Detailed microstructural characterization shows that the wires have an face centred cubic (FCC) crystal structure, and they have low-energy twin-boundary and stacking-fault defects along the growth direction. The wires exhibit remarkable thermal and mechanical stability that is critical for important applications. The alloy wires exhibit excellent electrocatalytic activity for methanol oxidation in an alkaline medium.

Single Nanowire Probe for Single Cell Endoscopy and Sensing

NASA Astrophysics Data System (ADS)

Yan, Ruoxue

The ability to manipulate light in subwavelength photonic and plasmonic structures has shown great potentials in revolutionizing how information is generated, transformed and processed. Chemically synthesized nanowires, in particular, offers a unique toolbox not only for highly compact and integrated photonic modules and devices, including coherent and incoherent light sources, waveguides, photodetectors and photovoltaics, but also for new types of nanoscopic bio-probes for spot cargo delivery and in-situ single cell endoscopy and sensing. Such nanowire probes would enable us to carry out intracellular imaging and probing with high spatial resolution, monitor in-vivo biological processes within single living cells and greatly improve our fundamental understanding of cell functions, intracellular physiological processes, and cellular signal pathways. My work is aimed at developing a material and instrumental platform for such single nanowire probe. Successful optical integration of Ag nanowire plasmonic waveguides, which offers deep subwavelength mode confinement, and conventional photonic waveguides was demonstrated on a single nanowire level. The highest plasmonic-photonic coupling efficiency coupling was found at small coupling angles and low input frequencies. The frequency dependent propagation loss was observed in Ag nanowire and was confirmed by quantitative measurement and in agreement with theoretical expectations. Rational integration of dielectric and Ag nanowire waveguide components into hybrid optical-plasmonic routing devices has been demonstrated. This capability is essential for incorporating sub-100nm Ag nanowire waveguides into optical fiber based nanoprobes for single cell endoscopy. The nanoprobe system based on single nanowire waveguides was demonstrated by optically coupling semiconductor or metal nanowire with an optical fiber with tapered tip. This nanoprobe design requires minimal instrumentation which makes it cost efficient and readily

Genetically Encoded Biosensors in Plants: Pathways to Discovery.

PubMed

Walia, Ankit; Waadt, Rainer; Jones, Alexander M

2018-04-29

Genetically encoded biosensors that directly interact with a molecule of interest were first introduced more than 20 years ago with fusion proteins that served as fluorescent indicators for calcium ions. Since then, the technology has matured into a diverse array of biosensors that have been deployed to improve our spatiotemporal understanding of molecules whose dynamics have profound influence on plant physiology and development. In this review, we address several types of biosensors with a focus on genetically encoded calcium indicators, which are now the most diverse and advanced group of biosensors. We then consider the discoveries in plant biology made by using biosensors for calcium, pH, reactive oxygen species, redox conditions, primary metabolites, phytohormones, and nutrients. These discoveries were dependent on the engineering, characterization, and optimization required to develop a successful biosensor; they were also dependent on the methodological developments required to express, detect, and analyze the readout of such biosensors.

Policy Considerations for Mobile Biosensors.

PubMed

Russell, Steven M; de la Rica, Roberto

2018-06-22

Meeting policy requirements is essential for advancing molecular diagnostic devices from the laboratory to real-world applications and commercialization. Considering policy as a starting point in the design of new technology is a winning strategy. Rapid developments have put mobile biosensors at the frontier of molecular diagnostics, at times outpacing policymakers, and therefore offering new opportunities for breakthroughs in global health. In this Perspective we survey influential global health policies and recent developments in mobile biosensing in order to gain a new perspective for the future of the field. We summarize the main requirements for mobile diagnostics outlined by policy makers such as the World Health Organization (WHO), the World Bank, the European Union (EU), and the Food and Drug Administration (FDA). We then classify current mobile diagnostic technologies according to the manner in which the biosensor interfaces with a smartphone. We observe a trend in reducing hardware components and substituting instruments and laborious data processing steps for user-friendly apps. From this perspective we see software application developers as key collaborators for bridging the gap between policy and practice.

David Adler Lectureship Award Talk: III-V Semiconductor Nanowires on Silicon for Future Devices

NASA Astrophysics Data System (ADS)

Riel, Heike

Bottom-up grown nanowires are very attractive materials for direct integration of III-V semiconductors on silicon thus opening up new possibilities for the design and fabrication of nanoscale devices for electronic, optoelectronic as well as quantum information applications. Template-Assisted Selective Epitaxy (TASE) allows the well-defined and monolithic integration of complex III-V nanostructures and devices on silicon. Achieving atomically abrupt heterointerfaces, high crystal quality and control of dimension down to 1D nanowires enabled the demonstration of FETs and tunnel devices based on In(Ga)As and GaSb. Furthermore, the strong influence of strain on nanowires as well as results on quantum transport studies of InAs nanowires with well-defined geometry will be presented.

Coupled, Simultaneous Displacement and Dealloying Reactions into Fe-Ni-Co Nanowires for Thinning Nanowire Segments.

PubMed

Geng, Xiaohua; Podlaha, Elizabeth J

2016-12-14

A new methodology is reported to shape template-assisted electrodeposition of Fe-rich, Fe-Ni-Co nanowires to have a thin nanowire segment using a coupled displacement reaction with a more noble elemental ion, Cu(II), and at the same time dealloying predominantly Fe from Fe-Ni-Co by the reduction of protons (H + ), followed by a subsequent etching step. The displacement/dealloyed layer was sandwiched between two trilayers of Fe-Ni-Co to facilitate the characterization of the reaction front, or penetration length. The penetration length region was found to be a function of the ratio of proton and Cu(II) concentration, and a ratio of 0.5 was found to provide the largest penetration rate, and hence the larger thinned length of the nanowire. Altering the etching time affected the diameter of the thinned region. This methodology presents a new way to thin nanowire segments connected to larger nanowire sections and also introduces a way to study the propagation of a reaction front into a nanowire.

Naringenin-responsive riboswitch-based fluorescent biosensor module for Escherichia coli co-cultures.

PubMed

Xiu, Yu; Jang, Sungho; Jones, J Andrew; Zill, Nicholas A; Linhardt, Robert J; Yuan, Qipeng; Jung, Gyoo Yeol; Koffas, Mattheos A G

2017-10-01

The ability to design and construct combinatorial synthetic metabolic pathways has far exceeded our capacity for efficient screening and selection of the resulting microbial strains. The need for high-throughput rapid screening techniques is of upmost importance for the future of synthetic biology and metabolic engineering. Here we describe the development of an RNA riboswitch-based biosensor module with dual fluorescent reporters, and demonstrate a high-throughput flow cytometry-based screening method for identification of naringenin over producing Escherichia coli strains in co-culture. Our efforts helped identify a number of key operating parameters that affect biosensor performance, including the selection of promoter and linker elements within the sensor-actuator domain, and the effect of host strain, fermentation time, and growth medium on sensor dynamic range. The resulting biosensor demonstrates a high correlation between specific fluorescence of the biosensor strain and naringenin titer produced by the second member of the synthetic co-culture system. This technique represents a novel application for synthetic microbial co-cultures and can be expanded from naringenin to any metabolite if a suitable riboswitch is identified. The co-culture technique presented here can be applied to a variety of target metabolites in combination with the SELEX approach for aptamer design. Due to the compartmentalization of the two genetic constructs responsible for production and detection into separate cells and application as independent modules of a synthetic microbial co-culture we have subsequently reduced the need for re-optimization of the producer module when the biosensor is replaced or removed. Biotechnol. Bioeng. 2017;114: 2235-2244. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Functionalised zinc oxide nanowire gas sensors: Enhanced NO(2) gas sensor response by chemical modification of nanowire surfaces.

PubMed

Waclawik, Eric R; Chang, Jin; Ponzoni, Andrea; Concina, Isabella; Zappa, Dario; Comini, Elisabetta; Motta, Nunzio; Faglia, Guido; Sberveglieri, Giorgio

2012-01-01

Surface coating with an organic self-assembled monolayer (SAM) can enhance surface reactions or the absorption of specific gases and hence improve the response of a metal oxide (MOx) sensor toward particular target gases in the environment. In this study the effect of an adsorbed organic layer on the dynamic response of zinc oxide nanowire gas sensors was investigated. The effect of ZnO surface functionalisation by two different organic molecules, tris(hydroxymethyl)aminomethane (THMA) and dodecanethiol (DT), was studied. The response towards ammonia, nitrous oxide and nitrogen dioxide was investigated for three sensor configurations, namely pure ZnO nanowires, organic-coated ZnO nanowires and ZnO nanowires covered with a sparse layer of organic-coated ZnO nanoparticles. Exposure of the nanowire sensors to the oxidising gas NO(2) produced a significant and reproducible response. ZnO and THMA-coated ZnO nanowire sensors both readily detected NO(2) down to a concentration in the very low ppm range. Notably, the THMA-coated nanowires consistently displayed a small, enhanced response to NO(2) compared to uncoated ZnO nanowire sensors. At the lower concentration levels tested, ZnO nanowire sensors that were coated with THMA-capped ZnO nanoparticles were found to exhibit the greatest enhanced response. ΔR/R was two times greater than that for the as-prepared ZnO nanowire sensors. It is proposed that the ΔR/R enhancement in this case originates from the changes induced in the depletion-layer width of the ZnO nanoparticles that bridge ZnO nanowires resulting from THMA ligand binding to the surface of the particle coating. The heightened response and selectivity to the NO(2) target are positive results arising from the coating of these ZnO nanowire sensors with organic-SAM-functionalised ZnO nanoparticles.

Contacts to Semiconductor Nanowires

DTIC Science & Technology

2009-10-03

SiNW diameters and the amount of metal deposited, or alternatively, the atomic ratio between Pt and Si. The uniformity of the silicided NWs was...program. The Schottky contact is a metal silicide formed by rapid thermal annealing of the deposited contact metal . The θ- Ni2Si/n-Si NW Schottky...decision. unless so designated by other documentation. 14. ABSTRACT Metal contacts to semiconductor nanowires share similarities with their thin-film

Nanowire sensors and arrays for chemical/biomolecule detection

NASA Technical Reports Server (NTRS)

Yun, Minhee; Lee, Choonsup; Vasquez, Richard P.; Ramanathan, K.; Bangar, M. A.; Chen, W.; Mulchandan, A.; Myung, N. V.

2005-01-01

We report electrochemical growth of single nanowire based sensors using e-beam patterned electrolyte channels, potentially enabling the controlled fabrication of individually addressable high density arrays. The electrodeposition technique results in nanowires with controlled dimensions, positions, alignments, and chemical compositions. Using this technique, we have fabricated single palladium nanowires with diameters ranging between 75 nm and 300 nm and conducting polymer nanowires (polypyrrole and polyaniline) with diameters between 100 nm and 200 nm. Using these single nanowires, we have successfully demonstrated gas sensing with Pd nanowires and pH sensing with polypirrole nanowires.

An immuno-biosensor system based on quartz crystal microbalance for avian influenza virus detection

NASA Astrophysics Data System (ADS)

Liu, Shengping; Chen, Guoming; Zhou, Qi; Wei, Yunlong

2007-12-01

For the quick detection of Avian Influenza Virus (AIV), a biosensor based on Quartz Crystal Microbalance (QCM) was fabricated according to the specific bonding principle between antibody and antigen. Staphylococcal Protein A (SPA) was extracted from Staphylococcus and purified. Then SPA was coated on the surface of QCM for immobilizing AIV monoclonal antibodies. The use of AIV monoclonal antibody could enhance the specificity of the immuno-biosensor. A multi-channel piezoelectricity detection system for the immuno-biosensor was developed. The system can work for the quick detection of AIV antigen in the case of the entirely aqueous status owe to one special oscillating circuit designed in this work. The optimum conditions of SPA coating and AIV monoclonal antibody immobilization were investigated utilizing the multi-channel detection system. The preliminary application of the immuno-biosensor system for detection of AIV was evaluated. Results indicate that the immuno-biosensor system can detect the AIV antigens with a linear range of 3-200ng/ml. The system can accomplish the detection of AIV antigens around 40 minutes.

Recent Development in Optical Fiber Biosensors

PubMed Central

Bosch, María Espinosa; Sánchez, Antonio Jesús Ruiz; Rojas, Fuensanta Sánchez; Ojeda, Catalina Bosch

2007-01-01

Remarkable developments can be seen in the field of optical fibre biosensors in the last decade. More sensors for specific analytes have been reported, novel sensing chemistries or transduction principles have been introduced, and applications in various analytical fields have been realised. This review consists of papers mainly reported in the last decade and presents about applications of optical fiber biosensors. Discussions on the trends in optical fiber biosensor applications in real samples are enumerated.

Fiber optic-based biosensor

NASA Technical Reports Server (NTRS)

Ligler, Frances S.

1991-01-01

The NRL fiber optic biosensor is a device which measures the formation of a fluorescent complex at the surface of an optical fiber. Antibodies and DNA binding proteins provide the mechanism for recognizing an analyze and immobilizing a fluorescent complex on the fiber surface. The fiber optic biosensor is fast, sensitive, and permits analysis of hazardous materials remote from the instrumentation. The fiber optic biosensor is described in terms of the device configuration, chemistry for protein immobilization, and assay development. A lab version is being used for assay development and performance characterization while a portable device is under development. Antibodies coated on the fiber are stable for up to two years of storage prior to use. The fiber optic biosensor was used to measure concentration of toxins in the parts per billion (ng/ml) range in under a minute. Immunoassays for small molecules and whole bacteria are under development. Assays using DNA probes as the detection element can also be used with the fiber optic sensor, which is currently being developed to detect biological warfare agents, explosives, pathogens, and toxic materials which pollute the environment.

Photoluminescence of etched SiC nanowires

NASA Astrophysics Data System (ADS)

Stewart, Polite D., Jr.; Rich, Ryan; Zerda, T. W.

2010-10-01

SiC nanowires were produced from carbon nanotubes and nanosize silicon powder in a tube furnace at temperatures between 1100^oC and 1350^oC. SiC nanowires had average diameter of 30 nm and very narrow size distribution. The compound possesses a high melting point, high thermal conductivity, and excellent wear resistance. The surface of the SiC nanowires after formation is covered by an amorphous layer. The composition of that layer is not fully understood, but it is believed that in addition to amorphous SiC it contains various carbon and silicon compounds, and SiO2. The objective of the research was to modify the surface structure of these SiC nanowires. Modification of the surface was done using the wet etching method. The etched nanowires were then analyzed using Fourier Transform Infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and photoluminescence (PL). FTIR and TEM analysis provided valid proof that the SiC nanowires were successfully etched. Also, the PL results showed that the SiC nanowire core did possess a fluorescent signal.

Optical biosensor with poly[N-nonyl-3,6-bis(ethylenedioxythiophene)carbazole] matrix for monitoring of phenol derivatives

NASA Astrophysics Data System (ADS)

Jedrychowska, Agnieszka; Malecha, Karol; Cabaj, Joanna; Sołoducho, Jadwiga

2014-08-01

The aim of the research was to develop an enzymatic, optical biosensor which provides quick and convenient determination of phenolic compounds in aqueous solutions. The biosensing strategy concerns design, fabrication and testing of a miniature ceramic-based biosensor which is destined for in-situ substrate monitoring. The base of the measuring system was fabricated using low temperature co-fired ceramics (LTCC) technology. The biocatalyst - laccase- was immobilized on the thin film of poly[N-nonyl-3,6-bis(ethylenedioxythiophene)carbazole] which provided good binding of the enzyme to the substrate and positively affected on the catalytic activity of the protein. In order to evaluate properties of the designed biosensor, its response for various concentrations of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diamonnium sal (ABTS) was measured. The optical biosensor produced by presented method could find applications in many fields, i.e. for detection of phenolic compounds in food products and beverages, in industry for control of technological processes or for environmental monitoring

Single bead-based electrochemical biosensor.

PubMed

Liu, Changchun; Schrlau, Michael G; Bau, Haim H

2009-12-15

A simple, robust, single bead-based electrochemical biosensor was fabricated and characterized. The sensor's working electrode consists of an electrochemically etched platinum wire, with a nominal diameter of 25 microm, hermetically heat-fusion sealed in a pulled glass capillary (micropipette). The sealing process does not require any epoxy or glue. A commercially available, densely functionalized agarose bead was mounted on the tip of the etched platinum wire. The use of a pre-functionalized bead eliminates the tedious and complicated surface functionalization process that is often the bottleneck in the development of electrochemical biosensors. We report on the use of a biotin agarose bead-based, micropipette, electrochemical (Bio-BMP) biosensor to monitor H(2)O(2) concentration and the use of a streptavidin bead-based, micropipette, electrochemical (SA-BMP) biosensor to detect DNA amplicons. The Bio-BMP biosensor's response increased linearly as the H(2)O(2) concentration increased in the range from 1 x 10(-6) to 1.2 x10(-4)M with a detection limit of 5 x 10(-7)M. The SA-BMP was able to detect the amplicons of 1pg DNA template of B. Cereus bacteria, thus providing better detection sensitivity than conventional gel-based electropherograms.

Controlled assembly of In2O3 nanowires on electronic circuits using scanning optical tweezers.

PubMed

Lee, Song-Woo; Jo, Gunho; Lee, Takhee; Lee, Yong-Gu

2009-09-28

In(2)O(3) nanowires can be used effectively as building blocks in the production of electronic circuits used in transparent and flexible electronic devices. The fabrication of these devices requires a controlled assembly of nanowires at crucial places and times. However, this kind of controlled assembly, which results in the fusion of nanowires to circuits, is still very difficult to execute. In this study, we demonstrate the benefits of using various lengths of In(2)O(3) nanowires by using non-contact mechanisms, such as scanning optical tweezers, to place them on designated targets during the fabrication process. Furthermore, these nanowires can be stabilized at both ends of the conducting wires using a focused laser, and later in the process, the annealed technique, so that proper flow of electrons is affected.

Metallic nanowire networks

DOEpatents

Song, Yujiang; Shelnutt, John A.

2012-11-06

A metallic nanowire network synthesized using chemical reduction of a metal ion source by a reducing agent in the presence of a soft template comprising a tubular inverse micellar network. The network of interconnected polycrystalline nanowires has a very high surface-area/volume ratio, which makes it highly suitable for use in catalytic applications.

NANOWIRE CATHODE MATERIAL FOR LITHIUM-ION BATTERIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

John Olson, PhD

2004-07-21

This project involved the synthesis of nanowire ã-MnO2 and characterization as cathode material for high-power lithium-ion batteries for EV and HEV applications. The nanowire synthesis involved the edge site decoration nanowire synthesis developed by Dr. Reginald Penner at UC Irvine (a key collaborator in this project). Figure 1 is an SEM image showing ã-MnO2 nanowires electrodeposited on highly oriented pyrolytic graphite (HOPG) electrodes. This technique is unique to other nanowire template synthesis techniques in that it produces long (>500 um) nanowires which could reduce or eliminate the need for conductive additives due to intertwining of fibers. Nanowire cathode for lithium-ionmore » batteries with surface areas 100 times greater than conventional materials can enable higher power batteries for electric vehicles (EVs) and hybrid electric vehicles (HEVs). The synthesis of the ã-MnO2 nanowires was successfully achieved. However, it was not found possible to co-intercalate lithium directly in the nanowire synthesis. Based on input from proposal reviewers, the scope of the project was altered to attempt the conversion into spinel LiMn2O4 nanowire cathode material by solid state reaction of the ã-MnO2 nanowires with LiNO3 at elevated temperatures. Attempts to perform the conversion on the graphite template were unsuccessful due to degradation of the graphite apparently caused by oxidative attack by LiNO3. Emphasis then shifted to quantitative removal of the nanowires from the graphite, followed by the solid state reaction. Attempts to quantitatively remove the nanowires by several techniques were unsatisfactory due to co-removal of excess graphite or poor harvesting of nanowires. Intercalation of lithium into ã-MnO2 electrodeposited onto graphite was demonstrated, showing a partial demonstration of the ã-MnO2 material as a lithium-ion battery cathode material. Assuming the issues of nanowires removal can be solved, the technique does offer potential for

Development of biosensors based on the one-dimensional semiconductor nanomaterials.

PubMed

Yan, Shancheng; Shi, Yi; Xiao, Zhongdang; Zhou, Minmin; Yan, Wenfu; Shen, Haoliang; Hu, Dong

2012-09-01

Biosensors are becoming increasingly important due to their applications in biological and chemical analyses, food safety industry, biomedical diagnostics, clinical detection, and environmental monitoring. Recent years, nanostructured semiconductor materials have been used to fabricate biosensors owing to their biocompatibility, low toxicity, high electron mobility, and easy fabrication. In the present study, we focus on recent various biosensors based on the one-dimensional semiconductor nanomaterials such as electrochemical biosensor, field-effect transistors biosensor, and label-free optical biosensor. In particular, the development of the electrochemical biosensor is discussed detailedly.

Co/Au multisegmented nanowires: a 3D array of magnetostatically coupled nanopillars

NASA Astrophysics Data System (ADS)

Bran, C.; Ivanov, Yu P.; Kosel, J.; Chubykalo-Fesenko, O.; Vazquez, M.

2017-03-01

Arrays of multisegmented Co/Au nanowires with designed segment lengths and diameters have been prepared by electrodeposition into aluminum oxide templates. The high quality of the Co/Au interface and the crystallographic structure of Co segments have determined by high-resolution transmission electron microscopy. Magnetic hysteresis loop measurements show larger coercivity and squareness of multisegmented nanowires as compared to single segment Co nanowires. The complementary micromagnetic simulations are in good agreement with the experimental results, confirming that the magnetic behavior is defined mainly by magnetostatic coupling between different segments. The proposed structure constitutes an innovative route towards a 3D array of synchronized magnetic nano-oscillators with large potential in nanoelectronics.

Simple fabricating PCB-based inter digital capacitor for glucose biosensor

NASA Astrophysics Data System (ADS)

Jamaluddin, Anif; Taufik, Usman; Iriani, Yofentina; Budiawanti, Sri; Suyitno

2017-01-01

This paper presents the simple fabrication of interdigital capacitor (IDC) using print circuit board (PCB) for glucose biosensor. PCB type FR04 laminated with Cu as electrode was used as sensor base. The IDC pattern of sensor was designed by computer aided design program and printed with a laser printer on plastic polymers. Then, the IDC pattern was transferred into PCB by a laminating machine. The etching process of PCB was done by immersing in ferric chloride liquid to form Cu pattern. There were five patterns of sensors including 5, 10, 15, 20 and 25 patterns. The capacitance value of PCB was measured with RCL meter when IDC biosensor was put in air, aquades, and glucose liquid with various moles of glucose (0.02, 0.04, 0.06, 0.08, 0.1M). In air medium, the increase of pattern number of IDC sensor (from 5 to 25) caused the sensor capacitance rose from 22 pf to 46 pf. In addition, the capacitance of sensor was dramatically increased until 0.36 µf while IDC sensor with 25 patterns was put in aquades medium. In liquid glucose medium, the capacitance of IDC biosensor with 25 patterns increased until 0.58 µf on 0.1 M glucose liquid.

Interactions between semiconductor nanowires and living cells.

PubMed

Prinz, Christelle N

2015-06-17

Semiconductor nanowires are increasingly used for biological applications and their small dimensions make them a promising tool for sensing and manipulating cells with minimal perturbation. In order to interface cells with nanowires in a controlled fashion, it is essential to understand the interactions between nanowires and living cells. The present paper reviews current progress in the understanding of these interactions, with knowledge gathered from studies where living cells were interfaced with vertical nanowire arrays. The effect of nanowires on cells is reported in terms of viability, cell-nanowire interface morphology, cell behavior, changes in gene expression as well as cellular stress markers. Unexplored issues and unanswered questions are discussed.

High Aspect Ratio Perforated Co₃O₄ Nanowires Derived from Cobalt-Carbonate-Hydroxide Nanowires with Enhanced Sensing Performance.

PubMed

Zhou, Tuantuan; Gao, Wanlin; Wang, Qiang; Umar, Ahmad

2018-05-01

Herein, we report the facile synthesis of high-aspect ratio perforated Co3O4 nanowires derived from cobalt-carbonate-hydroxide (Co(CO3)0.5(OH) 0.11H2O) nanowires. The Co(CO3)0.5(OH) 0.11H2O nanowires were synthesized by simple hydrothermal process at 120 °C while annealing of such nanowires at 400 °C leads the formation of perforated Co3O4 nanowires. The prepared nanowires were characterized by several techniques which confirmed the high aspect ratio and well-crystallinity for the synthesized nanowires. For application point of view, the prepared perforated Co3O4 nanowires were used as efficient electrode material to fabricate highly sensitive and selective hydrazine chemical sensor. The electrochemical impedance spectroscopy (EIS) technique was employed to confirm the successful modification of the electrode. The key parameters of chemical sensor, such as detection limit, sensitivity, and linear range, have been systematically explored. The fabricated hydrazine sensor displayed a rather low detection limit of 4.52 μM (S/N = 3), a good sensitivity of 25.70 μA · mM-1, and a wide linear range of 16.97-358.34 μM.

Synthetic biology for microbial heavy metal biosensors.

PubMed

Kim, Hyun Ju; Jeong, Haeyoung; Lee, Sang Jun

2018-02-01

Using recombinant DNA technology, various whole-cell biosensors have been developed for detection of environmental pollutants, including heavy metal ions. Whole-cell biosensors have several advantages: easy and inexpensive cultivation, multiple assays, and no requirement of any special techniques for analysis. In the era of synthetic biology, cutting-edge DNA sequencing and gene synthesis technologies have accelerated the development of cell-based biosensors. Here, we summarize current technological advances in whole-cell heavy metal biosensors, including the synthetic biological components (bioparts), sensing and reporter modules, genetic circuits, and chassis cells. We discuss several opportunities for improvement of synthetic cell-based biosensors. First, new functional modules must be discovered in genome databases, and this knowledge must be used to upgrade specific bioparts through molecular engineering. Second, modules must be assembled into functional biosystems in chassis cells. Third, heterogeneity of individual cells in the microbial population must be eliminated. In the perspectives, the development of whole-cell biosensors is also discussed in the aspects of cultivation methods and synthetic cells.

Fluorescent Proteins as Genetically Encoded FRET Biosensors in Life Sciences

PubMed Central

Hochreiter, Bernhard; Pardo Garcia, Alan; Schmid, Johannes A.

2015-01-01

Fluorescence- or Förster resonance energy transfer (FRET) is a measurable physical energy transfer phenomenon between appropriate chromophores, when they are in sufficient proximity, usually within 10 nm. This feature has made them incredibly useful tools for many biomedical studies on molecular interactions. Furthermore, this principle is increasingly exploited for the design of biosensors, where two chromophores are linked with a sensory domain controlling their distance and thus the degree of FRET. The versatility of these FRET-biosensors made it possible to assess a vast amount of biological variables in a fast and standardized manner, allowing not only high-throughput studies but also sub-cellular measurements of biological processes. In this review, we aim at giving an overview over the recent advances in genetically encoded, fluorescent-protein based FRET-biosensors, as these represent the largest and most vividly growing group of FRET-based sensors. For easy understanding, we are grouping them into four categories, depending on their molecular mechanism. These are based on: (a) cleavage; (b) conformational-change; (c) mechanical force and (d) changes in the micro-environment. We also address the many issues and considerations that come with the development of FRET-based biosensors, as well as the possibilities that are available to measure them. PMID:26501285

Nanowire array and nanowire solar cells and methods for forming the same

DOEpatents

Yang, Peidong [Berkeley, CA; Greene, Lori [Berkeley, CA; Law, Matthew [Berkeley, CA

2007-09-04

Homogeneous and dense arrays of nanowires are described. The nanowires can be formed in solution and can have average diameters of 40-300 nm and lengths of 1-3 .mu.m. They can be formed on any suitable substrate. Photovoltaic devices are also described.

Nanowire array and nanowire solar cells and methods for forming the same

DOEpatents

Yang, Peidong; Greene, Lori E.; Law, Matthew

2009-06-09

Homogeneous and dense arrays of nanowires are described. The nanowires can be formed in solution and can have average diameters of 40-300 nm and lengths of 1-3 .mu.m. They can be formed on any suitable substrate. Photovoltaic devices are also described.

Field-Effect Biosensors for On-Site Detection: Recent Advances and Promising Targets.

PubMed

Choi, Jaebin; Seong, Tae Wha; Jeun, Minhong; Lee, Kwan Hyi

2017-10-01

There is an explosive interest in the immediate and cost-effective analysis of field-collected biological samples, as many advanced biodetection tools are highly sensitive, yet immobile. On-site biosensors are portable and convenient sensors that provide detection results at the point of care. They are designed to secure precision in highly ionic and heterogeneous solutions with minimal hardware. Among various methods that are capable of such analysis, field-effect biosensors are promising candidates due to their unique sensitivity, manufacturing scalability, and integrability with computational circuitry. Recent developments in nanotechnological surface modification show promising results in sensing from blood, serum, and urine. This report gives a particular emphasis on the on-site efficacy of recently published field-effect biosensors, specifically, detection limits in physiological solutions, response times, and scalability. The survey of the properties and existing detection methods of four promising biotargets, exosomes, bacteria, viruses, and metabolites, aims at providing a roadmap for future field-effect and other on-site biosensors. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Biosensors and their applications in detection of organophosphorus pesticides in the environment.

PubMed

Hassani, Shokoufeh; Momtaz, Saeideh; Vakhshiteh, Faezeh; Maghsoudi, Armin Salek; Ganjali, Mohammad Reza; Norouzi, Parviz; Abdollahi, Mohammad

2017-01-01

This review discusses the past and recent advancements of biosensors focusing on detection of organophosphorus pesticides (OPs) due to their exceptional use during the last decades. Apart from agricultural benefits, OPs also impose adverse toxicological effects on animal and human population. Conventional approaches such as chromatographic techniques used for pesticide detection are associated with several limitations. A biosensor technology is unique due to the detection sensitivity, selectivity, remarkable performance capabilities, simplicity and on-site operation, fabrication and incorporation with nanomaterials. This study also provided specifications of the most OPs biosensors reported until today based on their transducer system. In addition, we highlighted the application of advanced complementary materials and analysis techniques in OPs detection systems. The availability of these new materials associated with new sensing techniques has led to introduction of easy-to-use analytical tools of high sensitivity and specificity in the design and construction of OPs biosensors. In this review, we elaborated the achievements in sensing systems concerning innovative nanomaterials and analytical techniques with emphasis on OPs.

Fabrication of amorphous silica nanowires via oxygen plasma treatment of polymers on silicon

NASA Astrophysics Data System (ADS)

Chen, Zhuojie; She, Didi; Chen, Qinghua; Li, Yanmei; Wu, Wengang

2018-02-01

We demonstrate a facile non-catalytic method of fabricating silica nanowires at room temperature. Different polymers including photoresists, parylene C and polystyrene are patterned into pedestals on the silicon substrates. The silica nanowires are obtained via the oxygen plasma treatment on those pedestals. Compared to traditional strategies of silica nanowire fabrication, this method is much simpler and low-cost. Through designing the proper initial patterns and plasma process parameters, the method can be used to fabricate various regiment nano-scale silica structure arrays in any laboratory with a regular oxygen-plasma-based cleaner or reactive-ion-etching equipment.

Amperometric Enzyme-Based Biosensors for Application in Food and Beverage Industry

NASA Astrophysics Data System (ADS)

Csöoregi, Elisabeth; Gáspñr, Szilveszter; Niculescu, Mihaela; Mattiasson, Bo; Schuhmann, Wolfgang

Continuous, sensitive, selective, and reliable monitoring of a large variety of different compounds in various food and beverage samples is of increasing importance to assure a high-quality and tracing of any possible source of contamination of food and beverages. Most of the presently used classical analytical methods are often requiring expensive instrumentation, long analysis times and well-trained staff. Amperometric enzyme-based biosensors on the other hand have emerged in the last decade from basic science to useful tools with very promising application possibilities in food and beverage industry. Amperometric biosensors are in general highly selective, sensitive, relatively cheap, and easy to integrate into continuous analysis systems. A successful application of such sensors for industrial purposes, however, requires a sensor design, which satisfies the specific needs of monitoring the targeted analyte in the particular application, Since each individual application needs different operational conditions and sensor characteristics, it is obvious that biosensors have to be tailored for the particular case. The characteristics of the biosensors are depending on the used biorecognition element (enzyme), nature of signal transducer (electrode material) and the communication between these two elements (electron-transfer pathway).

Magnetic and superconducting nanowires.

PubMed

Piraux, L; Encinas, A; Vila, L; Mátéfi-Tempfli, S; Mátéfi-Tempfli, M; Darques, M; Elhoussine, F; Michotte, S

2005-03-01

This article is focused on the use of electrodeposition and of various nanoporous templates for the fabrication of metallic nanowires made from single metals (Ni, Co, Pb, Sn), alloys (NiFe, CoFe, CoPt), and multilayers (Co/Cu, NiFe/Cu). An overview is given of our recent studies performed on both magnetic and superconducting nanowires. Using different approaches entailing measurements on both single wires and arrays, numerous interesting physical properties have been identified in relation to the nanoscopic dimensions of these materials. Finally, various novel applications of the nanowires are also discussed.

Nanowires, nanostructures and devices fabricated therefrom

DOEpatents

Majumdar, Arun; Shakouri, Ali; Sands, Timothy D.; Yang, Peidong; Mao, Samuel S.; Russo, Richard E.; Feick, Henning; Weber, Eicke R.; Kind, Hannes; Huang, Michael; Yan, Haoquan; Wu, Yiying; Fan, Rong

2005-04-19

One-dimensional nanostructures having uniform diameters of less than approximately 200 nm. These inventive nanostructures, which we refer to as "nanowires", include single-crystalline homostructures as well as heterostructures of at least two single-crystalline materials having different chemical compositions. Because single-crystalline materials are used to form the heterostructure, the resultant heterostructure will be single-crystalline as well. The nanowire heterostructures are generally based on a semiconducting wire wherein the doping and composition are controlled in either the longitudinal or radial directions, or in both directions, to yield a wire that comprises different materials. Examples of resulting nanowire heterostructures include a longitudinal heterostructure nanowire (LOHN) and a coaxial heterostructure nanowire (COHN).

Mode tunable p-type Si nanowire transistor based zero drive load logic inverter.

PubMed

Moon, Kyeong-Ju; Lee, Tae-Il; Lee, Sang-Hoon; Han, Young-Uk; Ham, Moon-Ho; Myoung, Jae-Min

2012-07-25

A design platform for a zero drive load logic inverter consisting of p-channel Si nanowire based transistors, which controlled their operating mode through an implantation into a gate dielectric layer was demonstrated. As a result, a nanowire based class D inverter having a 4.6 gain value at V(DD) of -20 V was successfully fabricated on a substrate.

BIOSENSORS

EPA Science Inventory

It has recently been proposed under the International Union of Pure and Applied Chemistry (IUPAC) Commission that biosensors be regarded as a subgroup of chemical sensors in which a biologically based mechanism is used for detection of the analyte. hemical sensors are defined und...

A creatinine biosensor based on admittance measurement

NASA Astrophysics Data System (ADS)

Ching, Congo Tak-Shing; Sun, Tai-Ping; Jheng, Deng-Yun; Tsai, Hou-Wei; Shieh, Hsiu-Li

2015-08-01

Regular check of blood creatinine level is very important as it is a measurement of renal function. Therefore, the objective of this study is to develop a simple and reliable creatinine biosensor based on admittance measurement for precise determination of creatinine. The creatinine biosensor was fabricated with creatinine deiminase immobilized on screen-printed carbon electrodes. Admittance measurement at a specific frequency ranges (22.80 - 84.71 Hz) showed that the biosensor has an excellent linear (r2 > 0.95) response range (50 - 250 uM), which covers the normal physiological and pathological ranges of blood creatinine levels. Intraclass correlation coefficient (ICC) showed that the biosensor has excellent reliability and validity (ICC = 0.98). In conclusion, a simple and reliable creatinine biosensor was developed and it is capable of precisely determining blood creatinine levels in both the normal physiological and pathological ranges.

Cellular manipulation and patterning using ferromagnetic nanowires

NASA Astrophysics Data System (ADS)

Hultgren, Anne

Ferromagnetic nanowires are demonstrated as an effective tool to apply forces to living cells. Both magnetic cell separations and the magnetic patterning of cells on a substrate will be accomplished through the use of cell-nanowire interactions as well as nanowire-magnetic field interactions. When introduced into cultures of NIH-3T3 cells, the nanowires are internalized by cells via the integrin-mediated adhesion pathway without inflicting any toxic effects on the cell cycle over the course of several days. In addition, the length of the nanowires was found to have an effect on the cell-nanowire interactions when the cells were dissociated from the tissue culture dish. To compare the effectiveness of the nanowires as a means of manipulating cells to the current technology which is based on superparamagnetic beads, magnetic cell separations were performed with electrodeposited Ni nanowires 350 nm in diameter and 5--35 mum long in field gradients of 80 T/m. Single-pass separations of NIH-3T3 cells bound to nanowires achieve up to 81% purity with 85% yield, a dramatic improvement over the 55% purity and 20% yield obtained with the beads. The yield for the separations were found to be dependent on the length of the nanowires, and was maximized when the length of the nanowires equaled the diameter of the cells. This dependence was exploited to perform a size-selective magnetic separation. Substrates containing arrays of micro-magnets, fabricated using photolithography, were placed in cell cultures. These micro-magnet arrays create regions of locally strong magnetic field gradients to trap nanowires in specific locations on the substrate. These substrates were used in conjunction with fluid flow and a weak, externally applied magnetic field to create and control patterns of cells bound to nanowires. Controlled isolation of heterogeneous pairs and groups of cells will enable the study of the biochemistry of cell-cell contacts.

Single-Mode Near-Infrared Lasing in a GaAsSb-Based Nanowire Superlattice at Room Temperature

NASA Astrophysics Data System (ADS)

Ren, Dingding; Ahtapodov, Lyubomir; Nilsen, Julie S.; Yang, Jianfeng; Gustafsson, Anders; Huh, Junghwan; Conibeer, Gavin J.; van Helvoort, Antonius T. J.; Fimland, Bjørn-Ove; Weman, Helge

2018-04-01

Semiconductor nanowire lasers can produce guided coherent light emission with miniaturized geometry, bringing about new possibility for a variety of applications including nanophotonic circuits, optical sensing, and on-chip and chip-to-chip optical communications. Here, we report on the realization of single-mode room-temperature lasing from 890 nm to 990 nm utilizing a novel design of single nanowires with GaAsSb-based multiple superlattices as gain medium under optical pumping. The wavelength tunability with comprehensively enhanced lasing performance is shown to result from the unique nanowire structure with efficient gain materials, which delivers a lasing quality factor as high as 1250, a reduced lasing threshold ~ 6 kW cm-2 and a high characteristic temperature ~ 129 K. These results present a major advancement for the design and synthesis of nanowire laser structures, which can pave the way towards future nanoscale integrated optoelectronic systems with stunning performance.

Functionalized xenon as a biosensor

PubMed Central

Spence, Megan M.; Rubin, Seth M.; Dimitrov, Ivan E.; Ruiz, E. Janette; Wemmer, David E.; Pines, Alexander; Yao, Shao Qin; Tian, Feng; Schultz, Peter G.

2001-01-01

The detection of biological molecules and their interactions is a significant component of modern biomedical research. In current biosensor technologies, simultaneous detection is limited to a small number of analytes by the spectral overlap of their signals. We have developed an NMR-based xenon biosensor that capitalizes on the enhanced signal-to-noise, spectral simplicity, and chemical-shift sensitivity of laser-polarized xenon to detect specific biomolecules at the level of tens of nanomoles. We present results using xenon “functionalized” by a biotin-modified supramolecular cage to detect biotin–avidin binding. This biosensor methodology can be extended to a multiplexing assay for multiple analytes. PMID:11535830

Boron carbide nanowires: Synthesis and characterization

NASA Astrophysics Data System (ADS)

Guan, Zhe

Bulk boron carbide has been widely used in ballistic armored vest and the property characterization has been heavily focused on mechanical properties. Even though boron carbides have also been projected as a promising class of high temperature thermoelectric materials for energy harvesting, the research has been limited in this field. Since the thermal conductivity of bulk boron carbide is still relatively high, there is a great opportunity to take advantage of the nano effect to further reduce it for better thermoelectric performance. This dissertation work aims to explore whether improved thermoelectric performance can be found in boron carbide nanowires compared with their bulk counterparts. This dissertation work consists of four main parts. (1) Synthesis of boron carbide nanowires. Boron carbide nanowires were synthesized by co-pyrolysis of diborane and methane at low temperatures (with 879 °C as the lowest) in a home-built low pressure chemical vapor deposition (LPCVD) system. The CVD-based method is energy efficient and cost effective. The as-synthesized nanowires were characterized by electron microscopy extensively. The transmission electron microscopy (TEM) results show the nanowires are single crystalline with planar defects. Depending on the geometrical relationship between the preferred growth direction of the nanowire and the orientation of the defects, the as-synthesized nanowires could be further divided into two categories: transverse fault (TF) nanowires grow normal to the defect plane, while axial fault (AF) ones grow within the defect plane. (2) Understanding the growth mechanism of as-synthesized boron carbide nanowires. The growth mechanism can be generally considered as the famous vapor-liquid-solid (VLS) mechanism. TF and AF nanowires were found to be guided by Ni-B catalysts of two phases. A TF nanowire is lead by a hexagonal phase catalyst, which was proved to be in a liquid state during reaction. While an AF nanowires is catalyzed by a

Ballistic superconductivity in semiconductor nanowires.

PubMed

Zhang, Hao; Gül, Önder; Conesa-Boj, Sonia; Nowak, Michał P; Wimmer, Michael; Zuo, Kun; Mourik, Vincent; de Vries, Folkert K; van Veen, Jasper; de Moor, Michiel W A; Bommer, Jouri D S; van Woerkom, David J; Car, Diana; Plissard, Sébastien R; Bakkers, Erik P A M; Quintero-Pérez, Marina; Cassidy, Maja C; Koelling, Sebastian; Goswami, Srijit; Watanabe, Kenji; Taniguchi, Takashi; Kouwenhoven, Leo P

2017-07-06

Semiconductor nanowires have opened new research avenues in quantum transport owing to their confined geometry and electrostatic tunability. They have offered an exceptional testbed for superconductivity, leading to the realization of hybrid systems combining the macroscopic quantum properties of superconductors with the possibility to control charges down to a single electron. These advances brought semiconductor nanowires to the forefront of efforts to realize topological superconductivity and Majorana modes. A prime challenge to benefit from the topological properties of Majoranas is to reduce the disorder in hybrid nanowire devices. Here we show ballistic superconductivity in InSb semiconductor nanowires. Our structural and chemical analyses demonstrate a high-quality interface between the nanowire and a NbTiN superconductor that enables ballistic transport. This is manifested by a quantized conductance for normal carriers, a strongly enhanced conductance for Andreev-reflecting carriers, and an induced hard gap with a significantly reduced density of states. These results pave the way for disorder-free Majorana devices.

Ballistic superconductivity in semiconductor nanowires

PubMed Central

Zhang, Hao; Gül, Önder; Conesa-Boj, Sonia; Nowak, Michał P.; Wimmer, Michael; Zuo, Kun; Mourik, Vincent; de Vries, Folkert K.; van Veen, Jasper; de Moor, Michiel W. A.; Bommer, Jouri D. S.; van Woerkom, David J.; Car, Diana; Plissard, Sébastien R; Bakkers, Erik P.A.M.; Quintero-Pérez, Marina; Cassidy, Maja C.; Koelling, Sebastian; Goswami, Srijit; Watanabe, Kenji; Taniguchi, Takashi; Kouwenhoven, Leo P.

2017-01-01

Semiconductor nanowires have opened new research avenues in quantum transport owing to their confined geometry and electrostatic tunability. They have offered an exceptional testbed for superconductivity, leading to the realization of hybrid systems combining the macroscopic quantum properties of superconductors with the possibility to control charges down to a single electron. These advances brought semiconductor nanowires to the forefront of efforts to realize topological superconductivity and Majorana modes. A prime challenge to benefit from the topological properties of Majoranas is to reduce the disorder in hybrid nanowire devices. Here we show ballistic superconductivity in InSb semiconductor nanowires. Our structural and chemical analyses demonstrate a high-quality interface between the nanowire and a NbTiN superconductor that enables ballistic transport. This is manifested by a quantized conductance for normal carriers, a strongly enhanced conductance for Andreev-reflecting carriers, and an induced hard gap with a significantly reduced density of states. These results pave the way for disorder-free Majorana devices. PMID:28681843

NANOSCALE BIOSENSORS IN ECOSYSTEM EXPOSURE RESEARCH

EPA Science Inventory

This powerpoint presentation presented information on nanoscale biosensors in ecosystem exposure research. The outline of the presentation is as follows: nanomaterials environmental exposure research; US agencies involved in nanosensor research; nanoscale LEDs in biosensors; nano...

Affinity Biosensors for Detection of Mycotoxins in Food.

PubMed

Evtugyn, Gennady; Subjakova, Veronika; Melikishvili, Sopio; Hianik, Tibor

2018-01-01

This chapter reviews recent achievements in methods of detection of mycotoxins in food. Special focus is on the biosensor technology that utilizes antibodies and nucleic acid aptamers as receptors. Development of biosensors is based on the immobilization of antibodies or aptamers onto various conventional supports like gold layer, but also on nanomaterials such as graphene oxide, carbon nanotubes, and quantum dots that provide an effective platform for achieving high sensitivity of detection using various physical methods, including electrochemical, mass sensitive, and optical. The biosensors developed so far demonstrate high sensitivity typically in subnanomolar limit of detection. Several biosensors have been validated in real samples. The sensitivity of biosensors is similar and, in some cases, even better than traditional analytical methods such as ELISA or chromatography. We believe that future trends will be focused on improving biosensor properties toward practical application in food industry. © 2018 Elsevier Inc. All rights reserved.

Protein Detection with Aptamer Biosensors

PubMed Central

Strehlitz, Beate; Nikolaus, Nadia; Stoltenburg, Regina

2008-01-01

Aptamers have been developed for different applications. Their use as new biological recognition elements in biosensors promises progress for fast and easy detection of proteins. This new generation of biosensor (aptasensors) will be more stable and well adapted to the conditions of real samples because of the specific properties of aptamers. PMID:27879936

Evaluation of an affinity-amplified immunoassay of graphene oxide using surface plasmon resonance biosensors

NASA Astrophysics Data System (ADS)

Chiu, Nan-Fu; Huang, Teng-Yi; Kuo, Chun-Chuan

2015-05-01

We describe a fundamental study on the plasmonic properties and advanced biosensing mechanisms of functionalized graphene. We discuss a specific design using modified carboxyl groups, which can modulate surface plasmon (SP) coupling and provide an advantage for their binding to the sensing layer with high-performance affinity in an immunological reaction. The functionalized graphene-based surface plasmon resonance (SPR) biosensors have three advantages: high performance, high sensitivity, and excellent molecular kinetic response. In the future, functionalized graphene sheets will make a unique contribution to photonic and SPR diagnosis devices. We wish to highlight the essential characteristics of functionalized graphene-based SPR biosensors to assist researchers in developing and advancing suitable biosensors for unique applications.

Amperometric biosensor for Salmonella typhimurium detection in milk

USDA-ARS?s Scientific Manuscript database

This paper reports an amperometric biosensor for rapid and sensitive Salmonella Typhimurium detection in milk. The biosensor was assembled from the self-assembled monolayers technique on a gold surface. In this device, polyclonal antibodies were oriented by protein A. The biosensor structure was cha...

In vitro evaluation of fluorescence glucose biosensor response.

PubMed

Aloraefy, Mamdouh; Pfefer, T Joshua; Ramella-Roman, Jessica C; Sapsford, Kim E

2014-07-08

Rapid, accurate, and minimally-invasive glucose biosensors based on Förster Resonance Energy Transfer (FRET) for glucose measurement have the potential to enhance diabetes control. However, a standard set of in vitro approaches for evaluating optical glucose biosensor response under controlled conditions would facilitate technological innovation and clinical translation. Towards this end, we have identified key characteristics and response test methods, fabricated FRET-based glucose biosensors, and characterized biosensor performance using these test methods. The biosensors were based on competitive binding between dextran and glucose to concanavalin A and incorporated long-wavelength fluorescence dye pairs. Testing characteristics included spectral response, linearity, sensitivity, limit of detection, kinetic response, reversibility, stability, precision, and accuracy. The biosensor demonstrated a fluorescence change of 45% in the presence of 400 mg/dL glucose, a mean absolute relative difference of less than 11%, a limit of detection of 25 mg/dL, a response time of 15 min, and a decay in fluorescence intensity of 72% over 30 days. The battery of tests presented here for objective, quantitative in vitro evaluation of FRET glucose biosensors performance have the potential to form the basis of future consensus standards. By implementing these test methods for a long-visible-wavelength biosensor, we were able to demonstrate strengths and weaknesses with a new level of thoroughness and rigor.

In Vitro Evaluation of Fluorescence Glucose Biosensor Response

PubMed Central

Aloraefy, Mamdouh; Pfefer, T. Joshua; Ramella-Roman, Jessica C.; Sapsford, Kim E.

2014-01-01

Rapid, accurate, and minimally-invasive glucose biosensors based on Förster Resonance Energy Transfer (FRET) for glucose measurement have the potential to enhance diabetes control. However, a standard set of in vitro approaches for evaluating optical glucose biosensor response under controlled conditions would facilitate technological innovation and clinical translation. Towards this end, we have identified key characteristics and response test methods, fabricated FRET-based glucose biosensors, and characterized biosensor performance using these test methods. The biosensors were based on competitive binding between dextran and glucose to concanavalin A and incorporated long-wavelength fluorescence dye pairs. Testing characteristics included spectral response, linearity, sensitivity, limit of detection, kinetic response, reversibility, stability, precision, and accuracy. The biosensor demonstrated a fluorescence change of 45% in the presence of 400 mg/dL glucose, a mean absolute relative difference of less than 11%, a limit of detection of 25 mg/dL, a response time of 15 min, and a decay in fluorescence intensity of 72% over 30 days. The battery of tests presented here for objective, quantitative in vitro evaluation of FRET glucose biosensors performance have the potential to form the basis of future consensus standards. By implementing these test methods for a long-visible-wavelength biosensor, we were able to demonstrate strengths and weaknesses with a new level of thoroughness and rigor. PMID:25006996

Coupling Molecular Beacons to Barcoded Metal Nanowires for Multiplexed, Sealed Chamber DNA Bioassays

PubMed Central

Stoermer, Rebecca L.; Cederquist, Kristin B.; McFarland, Sean K.; Sha, Michael Y.; Penn, Sharron G.

2010-01-01

We have combined molecular beacon (MB) probes with barcoded metal nanowires to enable no-wash, sealed chamber, multiplexed detection of nucleic acids. Probe design and experimental parameters important in nanowire-based MB assays are discussed. Loop regions of 24 bases and 5 base pair stem regions in the beacon probes gave optimal performance. Our results suggest that thermodynamic predictions for secondary structure stability of solution-phase MB can guide probe design for nanowire-based assays. Dengue virus-specific probes with predicted solution-phase ΔG of folding in 500 mM buffered NaCl of approximately −4 kcal/mol performed better than those with ΔG > −2 or < −6 kcal/mol. Buffered 300–500 mM NaCl was selected after comparison of several buffers previously reported for similar types of assays, and 200–500 mM NaCl was found to be the optimal ionic strength for the hybridization temperatures (25 and 50 °C) and probe designs used here. Target binding to the surface as a function of solution concentration fit a Sips isotherm with Kd = 1.7 ± 0.3 nM. The detection limit was ∼100 pM, limited by incomplete quenching. Single base mismatches could be discriminated from fully complementary targets. Oligonucleotide target sequences specific for human immunodeficiency, hepatitis C, and severe acute respiratory viruses were assayed simultaneously in a no-wash, sealed chamber, multiplexed experiment in which each of three probe sequences was attached to a different pattern of encoded nanowires. Finally, we demonstrated that probe-coated nanowires retain their selectivity and sensitivity in a triplexed assay after storage for over 3 months. PMID:17177440

Directed Evolution to Engineer Monobody for FRET Biosensor Assembly and Imaging at Live-Cell Surface.

PubMed

Limsakul, Praopim; Peng, Qin; Wu, Yiqian; Allen, Molly E; Liang, Jing; Remacle, Albert G; Lopez, Tyler; Ge, Xin; Kay, Brian K; Zhao, Huimin; Strongin, Alex Y; Yang, Xiang-Lei; Lu, Shaoying; Wang, Yingxiao

2018-04-19

Monitoring enzymatic activities at the cell surface is challenging due to the poor efficiency of transport and membrane integration of fluorescence resonance energy transfer (FRET)-based biosensors. Therefore, we developed a hybrid biosensor with separate donor and acceptor that assemble in situ. The directed evolution and sequence-function analysis technologies were integrated to engineer a monobody variant (PEbody) that binds to R-phycoerythrin (R-PE) dye. PEbody was used for visualizing the dynamic formation/separation of intercellular junctions. We further fused PEbody with the enhanced CFP and an enzyme-specific peptide at the extracellular surface to create a hybrid FRET biosensor upon R-PE capture for monitoring membrane-type-1 matrix metalloproteinase (MT1-MMP) activities. This biosensor revealed asymmetric distribution of MT1-MMP activities, which were high and low at loose and stable cell-cell contacts, respectively. Therefore, directed evolution and rational design are promising tools to engineer molecular binders and hybrid FRET biosensors for monitoring molecular regulations at the surface of living cells. Copyright © 2018 Elsevier Ltd. All rights reserved.

A compact superconducting nanowire memory element operated by nanowire cryotrons

NASA Astrophysics Data System (ADS)

Zhao, Qing-Yuan; Toomey, Emily A.; Butters, Brenden A.; McCaughan, Adam N.; Dane, Andrew E.; Nam, Sae-Woo; Berggren, Karl K.

2018-07-01

A superconducting loop stores persistent current without any ohmic loss, making it an ideal platform for energy efficient memories. Conventional superconducting memories use an architecture based on Josephson junctions (JJs) and have demonstrated access times less than 10 ps and power dissipation as low as 10-19 J. However, their scalability has been slow to develop due to the challenges in reducing the dimensions of JJs and minimizing the area of the superconducting loops. In addition to the memory itself, complex readout circuits require additional JJs and inductors for coupling signals, increasing the overall area. Here, we have demonstrated a superconducting memory based solely on lithographic nanowires. The small dimensions of the nanowire ensure that the device can be fabricated in a dense area in multiple layers, while the high kinetic inductance makes the loop essentially independent of geometric inductance, allowing it to be scaled down without sacrificing performance. The memory is operated by a group of nanowire cryotrons patterned alongside the storage loop, enabling us to reduce the entire memory cell to 3 μm × 7 μm in our proof-of-concept device. In this work we present the operation principles of a superconducting nanowire memory (nMem) and characterize its bit error rate, speed, and power dissipation.

Energy harvesting performance of piezoelectric ceramic and polymer nanowires.

PubMed

Crossley, Sam; Kar-Narayan, Sohini

2015-08-28

Energy harvesting from ubiquitous ambient vibrations is attractive for autonomous small-power applications and thus considerable research is focused on piezoelectric materials as they permit direct inter-conversion of mechanical and electrical energy. Nanogenerators (NGs) based on piezoelectric nanowires are particularly attractive due to their sensitivity to small-scale vibrations and may possess superior mechanical-to-electrical conversion efficiency when compared to bulk or thin-film devices of the same material. However, candidate piezoelectric nanowires have hitherto been predominantly analyzed in terms of NG output (i.e. output voltage, output current and output power density). Surprisingly, the corresponding dynamical properties of the NG, including details of how the nanowires are mechanically driven and its impact on performance, have been largely neglected. Here we investigate all realizable NG driving contexts separately involving inertial displacement, applied stress T and applied strain S, highlighting the effect of driving mechanism and frequency on NG performance in each case. We argue that, in the majority of cases, the intrinsic high resonance frequencies of piezoelectric nanowires (∼tens of MHz) present no barrier to high levels of NG performance even at frequencies far below resonance (<1 kHz) typically characteristic of ambient vibrations. In this context, we introduce vibrational energy harvesting (VEH) coefficients ηS and ηT, based on intrinsic materials properties, for comparing piezoelectric NG performance under strain-driven and stress-driven conditions respectively. These figures of merit permit, for the first time, a general comparison of piezoelectric nanowires for NG applications that takes into account the nature of the mechanical excitation. We thus investigate the energy harvesting performance of prototypical piezoelectric ceramic and polymer nanowires. We find that even though ceramic and polymer nanowires have been found, in

Transport properties of Sb doped Si nanowires

NASA Astrophysics Data System (ADS)

Nukala, Prathyusha; Sapkota, Gopal; Gali, Pradeep; Usha, Philipose

2011-10-01

n-type Si nanowires were synthesized at ambient pressure using SiCl4 as Si source and Sb source as the dopant. Sb doping of 3-4 wt % was achieved through a post growth diffusion technique. The nanowires were found to have an amorphous oxide shell that developed post-growth; the thickness of the shell is estimated to be about 3-4 nm. The composition of the amorphous shell covering the crystalline Si core was determined by Raman spectroscopy, with evidence that the shell was an amorphous oxide layer. Optical characterization of the as-grown nanowires showed green emission, attributed to the presence of the oxide shell covering the Si nanowire core. Etching of the oxide shell was found to decrease the intensity of this green emission. A single undoped Si nanowire contacted in an FET type configuration was found to be p-type with channel mobility of 20 cm^2V-1S-1. Sb doped Si nanowires exhibited n-type behavior, compensating for the holes in the undoped nanowire. The doped nanowires had carrier mobility and concentration of 160 cm^2V-1S-1 and 9.6 x 10^18cm-3 respectively.

Building a minimal and generalizable model of transcription factor-based biosensors: Showcasing flavonoids.

PubMed

Trabelsi, Heykel; Koch, Mathilde; Faulon, Jean-Loup

2018-05-07

Progress in synthetic biology tools has transformed the way we engineer living cells. Applications of circuit design have reached a new level, offering solutions for metabolic engineering challenges that include developing screening approaches for libraries of pathway variants. The use of transcription-factor-based biosensors for screening has shown promising results, but the quantitative relationship between the sensors and the sensed molecules still needs more rational understanding. Herein, we have successfully developed a novel biosensor to detect pinocembrin based on a transcriptional regulator. The FdeR transcription factor (TF), known to respond to naringenin, was combined with a fluorescent reporter protein. By varying the copy number of its plasmid and the concentration of the biosensor TF through a combinatorial library, different responses have been recorded and modeled. The fitted model provides a tool to understand the impact of these parameters on the biosensor behavior in terms of dose-response and time curves and offers guidelines to build constructs oriented to increased sensitivity and or ability of linear detection at higher titers. Our model, the first to explicitly take into account the impact of plasmid copy number on biosensor sensitivity using Hill-based formalism, is able to explain uncharacterized systems without extensive knowledge of the properties of the TF. Moreover, it can be used to model the response of the biosensor to different compounds (here naringenin and pinocembrin) with minimal parameter refitting. © 2018 Wiley Periodicals, Inc.

Surfactant-Templated Mesoporous Metal Oxide Nanowires

DOE PAGES

Luo, Hongmei; Lin, Qianglu; Baber, Stacy; ...

2010-01-01

We demore » monstrate two approaches to prepare mesoporous metal oxide nanowires by surfactant assembly and nanoconfinement via sol-gel or electrochemical deposition. For example, mesoporous Ta 2 O 5 and zeolite nanowires are prepared by block copolymer Pluronic 123-templated sol-gel method, and mesoporous ZnO nanowires are prepared by electrodeposition in presence of anionic surfactant sodium dodecyl sulfate (SDS) surfactant, in porous membranes. The morphologies of porous nanowires are studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses.« less

Nanoscale Biosensor Based on Silicon Photonic Cavity for Home Healthcare Diagnostic Application

NASA Astrophysics Data System (ADS)

Ebrahimy, Mehdi N.; Moghaddam, Aydin B.; Andalib, Alireza; Naziri, Mohammad; Ronagh, Nazli

2015-09-01

In this paper, a new ultra-compact optical biosensor based on photonic crystal (phc) resonant cavity is proposed. This sensor has ability to work in chemical optical processes for the determination and analysis of liquid material. Here, we used an optical filter based on two-dimensional phc resonant cavity on a silicon layer and an active area is created in center of cavity. According to results, with increasing the refractive index of cavity, resonant wavelengths shift so that this phenomenon provides the ability to measure the properties of materials. This novel designed biosensor has more advantage to operate in the biochemical process for example sensing protein and DNA molecule refractive index. This nanoscale biosensor has quality factor higher than 1.5 × 104 and it is suitable to be used in the home healthcare diagnostic applications.

Crystal phase-based epitaxial growth of hybrid noble metal nanostructures on 4H/fcc Au nanowires

NASA Astrophysics Data System (ADS)

Lu, Qipeng; Wang, An-Liang; Gong, Yue; Hao, Wei; Cheng, Hongfei; Chen, Junze; Li, Bing; Yang, Nailiang; Niu, Wenxin; Wang, Jie; Yu, Yifu; Zhang, Xiao; Chen, Ye; Fan, Zhanxi; Wu, Xue-Jun; Chen, Jinping; Luo, Jun; Li, Shuzhou; Gu, Lin; Zhang, Hua

2018-03-01

Crystal-phase engineering offers opportunities for the rational design and synthesis of noble metal nanomaterials with unusual crystal phases that normally do not exist in bulk materials. However, it remains a challenge to use these materials as seeds to construct heterometallic nanostructures with desired crystal phases and morphologies for promising applications such as catalysis. Here, we report a strategy for the synthesis of binary and ternary hybrid noble metal nanostructures. Our synthesized crystal-phase heterostructured 4H/fcc Au nanowires enable the epitaxial growth of Ru nanorods on the 4H phase and fcc-twin boundary in Au nanowires, resulting in hybrid Au-Ru nanowires. Moreover, the method can be extended to the epitaxial growth of Rh, Ru-Rh and Ru-Pt nanorods on the 4H/fcc Au nanowires to form unique hybrid nanowires. Importantly, the Au-Ru hybrid nanowires with tunable compositions exhibit excellent electrocatalytic performance towards the hydrogen evolution reaction in alkaline media.

Novel amperometric glucose biosensor based on MXene nanocomposite.

PubMed

Rakhi, R B; Nayak, Pranati; Xia, Chuan; Alshareef, Husam N

2016-11-10

A biosensor platform based on Au/MXene nanocomposite for sensitive enzymatic glucose detection is reported. The biosensor leverages the unique electrocatalytic properties and synergistic effects between Au nanoparticles and MXene sheets. An amperometric glucose biosensor is fabricated by the immobilization of glucose oxidase (GOx) enzyme on Nafion solubilized Au/ MXene nanocomposite over glassy carbon electrode (GCE). The biomediated Au nanoparticles play a significant role in facilitating the electron exchange between the electroactive center of GOx and the electrode. The GOx/Au/MXene/Nafion/GCE biosensor electrode displayed a linear amperometric response in the glucose concentration range from 0.1 to 18 mM with a relatively high sensitivity of 4.2 μAmM -1 cm -2 and a detection limit of 5.9 μM (S/N = 3). Furthermore, the biosensor exhibited excellent stability, reproducibility and repeatability. Therefore, the Au/MXene nanocomposite reported in this work is a potential candidate as an electrochemical transducer in electrochemical biosensors.

Novel amperometric glucose biosensor based on MXene nanocomposite

PubMed Central

Rakhi, R. B.; Nayuk, Pranati; Xia, Chuan; Alshareef, Husam N.

2016-01-01

A biosensor platform based on Au/MXene nanocomposite for sensitive enzymatic glucose detection is reported. The biosensor leverages the unique electrocatalytic properties and synergistic effects between Au nanoparticles and MXene sheets. An amperometric glucose biosensor is fabricated by the immobilization of glucose oxidase (GOx) enzyme on Nafion solubilized Au/ MXene nanocomposite over glassy carbon electrode (GCE). The biomediated Au nanoparticles play a significant role in facilitating the electron exchange between the electroactive center of GOx and the electrode. The GOx/Au/MXene/Nafion/GCE biosensor electrode displayed a linear amperometric response in the glucose concentration range from 0.1 to 18 mM with a relatively high sensitivity of 4.2 μAmM−1 cm−2 and a detection limit of 5.9 μM (S/N = 3). Furthermore, the biosensor exhibited excellent stability, reproducibility and repeatability. Therefore, the Au/MXene nanocomposite reported in this work is a potential candidate as an electrochemical transducer in electrochemical biosensors. PMID:27830757

Optical analysis of a III-V-nanowire-array-on-Si dual junction solar cell.

PubMed

Chen, Yang; Höhn, Oliver; Tucher, Nico; Pistol, Mats-Erik; Anttu, Nicklas

2017-08-07

A tandem solar cell consisting of a III-V nanowire subcell on top of a planar Si subcell is a promising candidate for next generation photovoltaics due to the potential for high efficiency. However, for success with such applications, the geometry of the system must be optimized for absorption of sunlight. Here, we consider this absorption through optics modeling. Similarly, as for a bulk dual-junction tandem system on a silicon bottom cell, a bandgap of approximately 1.7 eV is optimum for the nanowire top cell. First, we consider a simplified system of bare, uncoated III-V nanowires on the silicon substrate and optimize the absorption in the nanowires. We find that an optimum absorption in 2000 nm long nanowires is reached for a dense array of approximately 15 nanowires per square micrometer. However, when we coat such an array with a conformal indium tin oxide (ITO) top contact layer, a substantial absorption loss occurs in the ITO. This ITO could absorb 37% of the low energy photons intended for the silicon subcell. By moving to a design with a 50 nm thick, planarized ITO top layer, we can reduce this ITO absorption to 5%. However, such a planarized design introduces additional reflection losses. We show that these reflection losses can be reduced with a 100 nm thick SiO 2 anti-reflection coating on top of the ITO layer. When we at the same time include a Si 3 N 4 layer with a thickness of 90 nm on the silicon surface between the nanowires, we can reduce the average reflection loss of the silicon cell from 17% to 4%. Finally, we show that different approximate models for the absorption in the silicon substrate can lead to a 15% variation in the estimated photocurrent density in the silicon subcell.

Opto-mechano-electrical tripling in ZnO nanowires probed by photocurrent spectroscopy in a high-resolution transmission electron microscope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, C.; Golberg, D., E-mail: xuzhi@iphy.ac.cn, E-mail: golberg.dmitri@nims.go.jp; Graduate School of Pure and Applied Sciences, University of Tsukuba, Tennodai 1, Tsukuba, Ibaraki 3058577

2015-08-31

Photocurrent spectroscopy of individual free-standing ZnO nanowires inside a high-resolution transmission electron microscope (TEM) is reported. By using specially designed optical in situ TEM system capable of scanning tunneling microscopy probing paired with light illumination, opto-mechano-electrical tripling phenomenon in ZnO nanowires is demonstrated. Splitting of photocurrent spectra at around 3.3 eV under in situ TEM bending of ZnO nanowires directly corresponds to nanowire deformation and appearance of expanded and compressed nanowire sides. Theoretical simulation of a bent ZnO nanowire has an excellent agreement with the experimental data. The splitting effect could be explained by a change in the valence band structuremore » of ZnO nanowires due to a lattice strain. The strain-induced splitting provides important clues for future flexible piezo-phototronics.« less

New biosensor for detection of copper ions in water based on immobilized genetically modified yeast cells.

PubMed

Vopálenská, Irena; Váchová, Libuše; Palková, Zdena

2015-10-15

Contamination of water by heavy metals represents a potential risk for both aquatic and terrestrial organisms, including humans. Heavy metals in water resources can come from various industrial activities, and drinking water can be ex-post contaminated by heavy metals such as Cu(2+) from house fittings (e.g., water reservoirs) and pipes. Here, we present a new copper biosensor capable of detecting copper ions at concentrations of 1-100 μM. This biosensor is based on cells of a specifically modified Saccharomyces cerevisiae strain immobilized in alginate beads. Depending on the concentration of copper, the biosensor beads change color from white, when copper is present in concentrations below the detection limit, to pink or red based on the increase in copper concentration. The biosensor was successfully tested in the determination of copper concentrations in real samples of water contaminated with copper ions. In contrast to analytical methods or other biosensors based on fluorescent proteins, the newly designed biosensor does not require specific equipment and allows the quick detection of copper in many parallel samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Epitaxy of advanced nanowire quantum devices

NASA Astrophysics Data System (ADS)

Gazibegovic, Sasa; Car, Diana; Zhang, Hao; Balk, Stijn C.; Logan, John A.; de Moor, Michiel W. A.; Cassidy, Maja C.; Schmits, Rudi; Xu, Di; Wang, Guanzhong; Krogstrup, Peter; Op Het Veld, Roy L. M.; Zuo, Kun; Vos, Yoram; Shen, Jie; Bouman, Daniël; Shojaei, Borzoyeh; Pennachio, Daniel; Lee, Joon Sue; van Veldhoven, Petrus J.; Koelling, Sebastian; Verheijen, Marcel A.; Kouwenhoven, Leo P.; Palmstrøm, Chris J.; Bakkers, Erik P. A. M.

2017-08-01

Semiconductor nanowires are ideal for realizing various low-dimensional quantum devices. In particular, topological phases of matter hosting non-Abelian quasiparticles (such as anyons) can emerge when a semiconductor nanowire with strong spin-orbit coupling is brought into contact with a superconductor. To exploit the potential of non-Abelian anyons—which are key elements of topological quantum computing—fully, they need to be exchanged in a well-controlled braiding operation. Essential hardware for braiding is a network of crystalline nanowires coupled to superconducting islands. Here we demonstrate a technique for generic bottom-up synthesis of complex quantum devices with a special focus on nanowire networks with a predefined number of superconducting islands. Structural analysis confirms the high crystalline quality of the nanowire junctions, as well as an epitaxial superconductor-semiconductor interface. Quantum transport measurements of nanowire ‘hashtags’ reveal Aharonov-Bohm and weak-antilocalization effects, indicating a phase-coherent system with strong spin-orbit coupling. In addition, a proximity-induced hard superconducting gap (with vanishing sub-gap conductance) is demonstrated in these hybrid superconductor-semiconductor nanowires, highlighting the successful materials development necessary for a first braiding experiment. Our approach opens up new avenues for the realization of epitaxial three-dimensional quantum architectures which have the potential to become key components of various quantum devices.

Carbon-silicon core-shell nanowires as high capacity electrode for lithium ion batteries.

PubMed

Cui, Li-Feng; Yang, Yuan; Hsu, Ching-Mei; Cui, Yi

2009-09-01

We introduce a novel design of carbon-silicon core-shell nanowires for high power and long life lithium battery electrodes. Amorphous silicon was coated onto carbon nanofibers to form a core-shell structure and the resulted core-shell nanowires showed great performance as anode material. Since carbon has a much smaller capacity compared to silicon, the carbon core experiences less structural stress or damage during lithium cycling and can function as a mechanical support and an efficient electron conducting pathway. These nanowires have a high charge storage capacity of approximately 2000 mAh/g and good cycling life. They also have a high Coulmbic efficiency of 90% for the first cycle and 98-99.6% for the following cycles. A full cell composed of LiCoO(2) cathode and carbon-silicon core-shell nanowire anode is also demonstrated. Significantly, using these core-shell nanowires we have obtained high mass loading and an area capacity of approximately 4 mAh/cm(2), which is comparable to commercial battery values.

Poly(aniline) nanowires in sol-gel coated ITO: A pH-responsive substrate for planar supported lipid bilayers

PubMed Central

Ge, Chenhao; Orosz, Kristina S.; Armstrong, Neal R.; Saavedra, S. Scott

2011-01-01

Facilitated ion transport across an artificial lipid bilayer coupled to a solid substrate is a function common to several types of bioelectronic devices based on supported membranes, including biomimetic fuel cells and ion channel biosensors. Described here is fabrication of a pH-sensitive transducer composed of a porous sol-gel layer derivatized with poly(aniline) (PANI) nanowires grown from an underlying planar indium-tin oxide (ITO) electrode. The upper sol-gel surface is hydrophilic, smooth, and compatible with deposition of a planar supported lipid bilayer (PSLB) formed via vesicle fusion. Conducting tip AFM was used to show that the PANI wires are connected to the ITO, which convert this electrode into a potentiometric pH sensor. The response to changes in the pH of the buffer contacting the PANI nanowire/sol-gel/ITO electrode is blocked by the very low ion permeability of the overlying, fluid PSLB. The feasibility of using this assembly to monitor facilitated proton transport across the PSLB was demonstrated by doping the membrane with lipophilic ionophores that respond to a transmembrane pH gradient, which produced an apparent proton permeability several orders of magnitude greater than values measured for undoped lipid bilayers. PMID:21707069

Surface sensitization mechanism on negative electron affinity p-GaN nanowires

NASA Astrophysics Data System (ADS)

Diao, Yu; Liu, Lei; Xia, Sihao; Feng, Shu; Lu, Feifei

2018-03-01

The surface sensitization is the key to prepare negative electron affinity photocathode. The thesis emphasizes on the study of surface sensitization mechanism of p-type doping GaN nanowires utilizing first principles based on density function theory. The adsorption energy, work function, dipole moment, geometry structure, electronic structure and optical properties of Mg-doped GaN nanowires surfaces with various coverages of Cs atoms are investigated. The GaN nanowire with Mg doped in core position is taken as the sensitization base. At the initial stage of sensitization, the best adsorption site for Cs atom on GaN nanowire surface is BN, the bridge site of two adjacent N atoms. Surface sensitization generates a p-type internal surface with an n-type surface state, introducing a band bending region which can help reduce surface barrier and work function. With increasing Cs coverage, work functions decrease monotonously and the "Cs-kill" phenomenon disappears. For Cs coverage of 0.75 ML and 1 ML, the corresponding sensitization systems reach negative electron affinity state. Through surface sensitization, the absorption curves are red shifted and the absorption coefficient is cut down. All theoretical calculations can guide the design of negative electron affinity Mg doped GaN nanowires photocathode.

Electrically Conductive and Optically Active Porous Silicon Nanowires

PubMed Central

Qu, Yongquan; Liao, Lei; Li, Yujing; Zhang, Hua; Huang, Yu; Duan, Xiangfeng

2009-01-01

We report the synthesis of vertical silicon nanowire array through a two-step metal-assisted chemical etching of highly doped n-type silicon (100) wafers in a solution of hydrofluoric acid and hydrogen peroxide. The morphology of the as-grown silicon nanowires is tunable from solid nonporous nanowires, nonporous/nanoporous core/shell nanowires, and entirely nanoporous nanowires by controlling the hydrogen peroxide concentration in the etching solution. The porous silicon nanowires retain the single crystalline structure and crystallographic orientation of the starting silicon wafer, and are electrically conductive and optically active with visible photoluminescence. The combination of electronic and optical properties in the porous silicon nanowires may provide a platform for the novel optoelectronic devices for energy harvesting, conversion and biosensing. PMID:19807130