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Clive L Baveghems, Murali Anuganti, Ajith Pattammattel, Yao Lin, Challa V Kumar
Using glucose oxidase (GOx) and α-Zr(IV)phosphate nanoplates (α-ZrP) as a model system, a generally applicable approach to control enzyme-solid interactions via chemical modification of amino acid side chains of the enzyme is demonstrated. Net charge on GOx was systematically tuned by appending different amounts of polyamine to the protein surface to produce chemically modified GOx(n), where n is the net charge on the enzyme after the modification and ranged from -62 to +95 electrostatic units in the system...
December 11, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Enyi Guo, David R McKenzie
Electron fluxes crossing the interface between a metallic conductor and an aqueous environment are important in many fields; hydrogen production, environmental scanning tunnelling microscopy, scanning electrochemical microscopy being some of them. Gurney (Gurney 1931 Proc. R. Soc. Lond.134, 137 (doi:10.1098/rspa.1931.0187)) provided in 1931 a scheme for tunnelling during electrolysis and outlined conditions for it to occur. We measure the low-voltage current flows between gold electrodes in pure water and use the time-dependent behaviour at voltage switch-on and switch-off to evaluate the relative contribution to the steady current arising from tunnelling of electrons between the electrodes and ions in solution and from the neutralization of ions adsorbed onto the electrode surface...
November 2017: Proceedings. Mathematical, Physical, and Engineering Sciences
Stuti Bhagat, N V Srikanth Vallabani, Vaithiyalingam Shutthanandan, Mark Bowden, Ajay S Karakoti, Sanjay Singh
Catalytically active individual gold (Au) and cerium oxide (CeO2) nanoparticles (NPs) are well known to exhibit specific enzyme-like activities, such as natural catalase, oxidase, superoxide dismutase, and peroxidase enzymes. These activities have been maneuvered to design several biological applications such as immunoassays, glucose detection, radiation and free radical protection and tissue engineering. In biological systems, multienzyme complexes are involved in catalyzing important reactions of essential metabolic processes such as respiration, biomolecule synthesis, and photosynthesis...
December 7, 2017: Journal of Colloid and Interface Science
Moonseong Park, Charles Soon Hong Hwang, Ki-Hun Jeong
Plasmonic alloy has attracted much interest in tailoring localized surface plasmon resonance (LSPR) for recent biosensing techniques. In particular, paper-based plasmonic substrates allow capillary-driven lateral flow as well as three-dimensional metal nanostructures and therefore they become actively transferred to LSPR-based biosensing such as surface-enhanced Raman spectroscopy (SERS) or metal-enhanced fluorescence (MEF). However, employing plasmonic alloy nanoislands on heat-sensitive substrate is still challenging, which significantly inhibits broad-range tailoring of the plasmon resonance wavelength (PRW) for superior sensitivity...
December 8, 2017: ACS Applied Materials & Interfaces
Zhao Li, Haibao Peng, Jialin Liu, Ye Tian, Wuli Yang, Jinrong Yao, Zhengzhong Shao, Xin Chen
Nowadays, fluorescence detection has emerged as one of the most frequently used non-invasive biosensing method to selectively monitor biological processes within living systems. Among fluorescent nanoparticles, gold nanoclusters (AuNCs) have been intensively studied because of their intrinsic fluorescence and their endowed biocompatible surface. Herein, we selected an abundant, low-cost and sustainable plant protein, the pea protein isolate (PPI) for its excellent biocompatibility, biodegradability, and non-allergenic character, to be employed as both a reducing and stabilizing agent to facilely produce AuNCs exhibiting a strong red fluorescence...
December 8, 2017: ACS Applied Materials & Interfaces
Gaspard Huber, Estelle Léonce, Orsola Baydoun, Nicolas De Rycke, Thierry Brotin, Patrick Berthault
Cryptophanes, cage-molecules constituted of aromatic bowls, are now well recognized as powerful xenon hosts in 129 Xe NMR-based biosensing. In the quest of a dual probe that can be addressed only by NMR we have studied three cryptophanes bearing a tether with an unsaturated bond. The idea behind this is to build probes that can be detected both via hyperpolarised 129 Xe NMR and Para-Hydrogen Induced Polarisation (PHIP) 1 H NMR. Only two of the three cryptophanes experience a sufficiently fast hydrogenation enabling the PHIP effect...
December 8, 2017: Magnetic Resonance in Chemistry: MRC
Vibol Sok, Alex Fragoso
Carbon nanomaterials have emerged as suitable supports for enzyme immobilization and stabilization due to their inherently large surface area, high electrical conductivity, chemical stability and mechanical strength. In this paper, carbon nano-onions (CNOs) were used as supports to immobilize alkaline phosphatase, horseradish peroxidase and glucose oxidase. CNOs were first functionalized by oxidation to generate carboxylic groups on the surface followed by the covalent linking of the using a soluble carbodiimide as coupling agent...
December 7, 2017: Preparative Biochemistry & Biotechnology
Zahra Aghili, Navid Nasirizadeh, Adeleh Divsalar, Shahram Shoeibi, Parichehreh Yaghmaei
Early detection of Parkinson's disease (PD), as a dangerous neurodegenerative disease, is a key factor in the therapy or prevention of further development of this disease. We developed an electrochemical nanobiosensor for early detection of PD based on the quantification of circulating biomarker, miR-195. Exfoliated graphene oxide (EGO) and gold nanowires (GNWs) were used to modify the surface of screen-printed carbon electrode. A single-strand thiolated probe was designed for specific hybridization with target miRNA (miR-195), and doxorubicin was used as an electrochemical indicator for differential pulse voltammetry measurements...
December 7, 2017: Artificial Cells, Nanomedicine, and Biotechnology
Ping Li, Xiaoqiu Dou, Chuanliang Feng, Holger Schönherr
Herein, fabrication and modification of novel bio-inspired microwell arrays with nanoscale topographic structures are reported. The natural nano- and microstructures present on the surface of rose petals were hypothesized to enhance cell-surface contacts. Thus hierarchically structured polyethylene terephthalate glycol modified (PETG) substrates were fabricated by replication from rose petals via nanoimprint lithography, followed by covalent modification and crosslinking with RGD-presenting gelatin-methacrylate (GelMA) for promoting cell adhesion and spreading...
December 6, 2017: Biomaterials Science
Xuan Liu, Hui Jiang
Biosensors for proteins have shown attractive advantages compared to traditional techniques in clinical laboratory diagnosis. In virtue of modern fabrication modes and detection techniques, various immunosensing platforms have been reported on basis of the specific recognition between antigen-antibody pairs. In addition to profit from the development of nanotechnology and molecular biology, diverse fabrication and signal amplification strategies have been designed for detection of protein antigens, which has led to great achievements in fast quantitative and simultaneous testing with extremely high sensitivity and specificity...
December 4, 2017: Sensors
Shijie Deng, Peng Wang, Xinglong Yu
Surface plasmon resonance (SPR) is an optical sensing technique that is capable of performing real-time, label-free and high-sensitivity monitoring of molecular interactions. SPR biosensors can be divided according to their operating principles into angle-, wavelength-, intensity- and phase-interrogated devices. With their complex optical configurations, phase-interrogated SPR sensors generally provide higher sensitivity and throughput, and have thus recently emerged as prominent biosensing devices. To date, several methods have been developed for SPR phase interrogation, including heterodyne detection, polarimetry, shear interferometry, spatial phase modulation interferometry and temporal phase modulation interferometry...
December 5, 2017: Sensors
Gayathri Rajeev, Beatriz Prieto Simon, Lluis F Marsal, Nicolas H Voelcker
There is a strong and growing demand for compact, portable, rapid, and low-cost devices to detect biomarkers of interest in clinical and point-of-care diagnostics. Such devices aid in early diagnosis of diseases without the need to rely on expensive and time-consuming large instruments in dedicated laboratories. Over the last decade, numerous biosensors have been developed for detection of a wide range of clinical biomarkers including proteins, nucleic acids, growth factors, and bacterial enzymes. Various transduction techniques have been reported based on biosensor technology that deliver substantial advances in analytical performance, including sensitivity, reproducibility, selectivity, and speed for monitoring a wide range of human health conditions...
December 5, 2017: Advanced Healthcare Materials
Mehmet Isik, Luca Porcarelli, Nerea Lago, Haijin Zhu, Maria Forsyth, David Mecerreyes
Proton conducting polymeric membranes are highly searched in many different technologies ranging from energy to biosensing. Protic ionic liquids and their polymeric version represent a new family of proton conducting molecules with relatively facile synthesis and excellent properties. In this work, protic poly(ionic liquids) having the most popular phosphonium counter-cations are presented for the first time. The synthesis is carried out through proton transfer reactions or through ion exchange reactions by using commercially available tertiary phosphines...
December 4, 2017: Macromolecular Rapid Communications
Tzu-Yen Huang, Chung-Wei Kung, Yu-Te Liao, Sheng-Yuan Kao, Mingshan Cheng, Ting-Hsiang Chang, Joel Henzie, Hatem R Alamri, Zeid A Alothman, Yusuke Yamauchi, Kuo-Chuan Ho, Kevin C-W Wu
With the aim of a reliable biosensing exhibiting enhanced sensitivity and selectivity, this study demonstrates a dopamine (DA) sensor composed of conductive poly(3,4-ethylenedioxythiophene) nanotubes (PEDOT NTs) conformally coated with porphyrin-based metal-organic framework nanocrystals (MOF-525). The MOF-525 serves as an electrocatalytic surface, while the PEDOT NTs act as a charge collector to rapidly transport the electron from MOF nanocrystals. Bundles of these particles form a conductive interpenetrating network film that together: (i) improves charge transport pathways between the MOF-525 regions and (ii) increases the electrochemical active sites of the film...
November 2017: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
Zhikun Zhang, Yang Liu, Peifeng Liu, Lu Yang, Xingyu Jiang, Dan Luo, Dayong Yang
Chirality plays essential roles in life systems such that l-amino acids (LAAs) are predominantly found as the building units of protein for organisms. The presence of the d-enantiomer (DAA) has been found to be specifically relevant to gastric cancer. We herein construct a luminescent DNA/silver nanocluster based biosensing system to achieve rapid and specific detection of DAAs. As a proof of application, we detected DAAs in saliva samples from patients with gastric cancer, and the test results exhibited excellent specificity...
December 4, 2017: Nanoscale
Bobin Lee, Jin-Ho Park, Ju-Young Byun, Joon Heon Kim, Min-Gon Kim
Label-free biosensing methods that rely on the use of localized surface plasmon resonance (LSPR) have attracted great attention as a result of their simplicity, high sensitivity, and relatively low cost. However, in-situ analysis of real samples using these techniques has remained challenging because colloidal nanoparticles (NPs) can be unstable at certain levels of pH and salt concentration. Even in the case of a chip-type LSPR sensor that can resolve the instability problem by employing NPs immobilized on the substrate, loading of a sample to sensor chip with exact volume control can be difficult for unskilled users...
November 26, 2017: Biosensors & Bioelectronics
Nadiya T Darwish, Shamala D Sekaran, Yatimah Alias, Sook Mei Khor
The sharp increase in incidence of dengue infection has necessitated the development of methods for the rapid diagnosis of this deadly disease. Here we report the design and development of a reliable, sensitive, and specific optical immunosensor for the detection of the dengue nonstructural protein 1 (NS1) biomarker in clinical samples obtained during early stages of infection. The present optical NS1 immunosensor comprises a biosensing surface consisting of specific monoclonal NS1 antibody for immunofluorescence-based NS1 antigen determination using fluorescein isothiocyanate (FITC) conjugated to IgG antibody...
November 30, 2017: Journal of Pharmaceutical and Biomedical Analysis
Hiofan Hoi, Salva S Rezaie, Lu Gong, Payel Sen, Hongbo Zeng, Carlo Montemagno, Manisha Gupta
Silicon nitride (SiNx) based biosensors have the potential to converge on the technological achievements of semiconductor microfabrication and biotechnology. Development of biofunctionalized SiNx surface and its integration with other devices will allow us to integrate the biosensing capability with probe control, data acquisition and data processing. Here we use the hydrogen plasma generated by inductively coupled plasma-reactive ion etching (ICP-RIE) technique to produce amino-functionality on the surface of SiNx which can then be readily used for biomolecule immobilization...
November 23, 2017: Biosensors & Bioelectronics
Anna-Maria Pappa, Onur Parlak, Gaetan Scheiblin, Pascal Mailley, Alberto Salleo, Roisin M Owens
In this review we focus on demonstrating how organic electronic materials can solve key problems in biosensing thanks to their unique material properties and implementation in innovative device configurations. We highlight specific examples where these materials solve multiple issues related to complex sensing environments, and we benchmark these examples by comparing them to state-of-the-art commercially available sensing using alternative technologies. We have categorized our examples by sample type, focusing on sensing from body fluids in vitro and on wearable sensors, which have attracted significant interest owing to their integration with everyday life activities...
November 28, 2017: Trends in Biotechnology
Alireza Abi, Zahra Mohammadpour, Xiaolei Zuo, Afsaneh Safavi
The detection of biomarkers using sensitive and selective analytical devices is critically important for the early stage diagnosis and treatment of diseases. The synergy between the high specificity of nucleic acid recognition units and the great sensitivity of electrochemical signal transductions has already shown promise for the development of efficient biosensing platforms. Yet nucleic-acid based electrochemical biosensors often rely on target amplification strategies (e.g., polymerase chain reactions) to detect analytes at clinically relevant concentration ranges...
November 4, 2017: Biosensors & Bioelectronics
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