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Annamaria Ruscito, Erin M McConnell, Anna Koudrina, Ranganathan Velu, Christopher Mattice, Vernon Hunt, Maureen McKeague, Maria C DeRosa
Aptamers, synthetic oligonucleotide-based molecular recognition probes, have found use in a wide array of biosensing technologies based on their tight and highly selective binding to a variety of molecular targets. However, the inherent challenges associated with the selection and characterization of aptamers for small molecule targets have resulted in their underrepresentation, despite the need for small molecule detection in fields such as medicine, the environment, and agriculture. This protocol describes the steps in the selection, sequencing, affinity characterization, and truncation of DNA aptamers that are specific for small molecule targets...
December 14, 2017: Current Protocols in Chemical Biology
Meng Liu, Qingxin Yin, Erin McConnell, Yangyang Chang, John Brennan, Yingfu Li
Technologies capable of linking DNA amplification to molecular recognition are very desirable for ultrasensitive biosensing applications. We have developed a simple but powerful isothermal DNA amplification method, termed DNAzyme feedback amplification (DFA), that is capable of relaying molecular recognition to exponential DNA amplification. The method incorporates both an RNA-cleaving DNAzyme (RCD) and rolling circle amplification (RCA) carried out by a special DNA polymerase using a circular DNA template...
December 14, 2017: Chemistry: a European Journal
Sankhyabrata Bandyopadhyay, Palas Biswas, Francesco Chiavaioli, Tanoy Kumar Dey, Nandini Basumallick, Cosimo Trono, Ambra Giannetti, Sara Tombelli, Francesco Baldini, Somnath Bandyopadhyay
In this paper, a detailed investigation on the modeling of long-period fiber grating (LPFG) sensors is discussed with the aim of providing a more realistic solution for their use in biosensing. Add-layer sensitivity, i.e., sensitivity of the sensor to an additional layer adhered onto the fiber surface, is quantified and a clear and complete analysis about the influence of the average thickness of the deposited biological sensing layers, as well as the change in refractive index of these layers, on the resonant wavelength of the cladding modes of an LPFG is provided...
December 10, 2017: Applied Optics
Rikuta Hamaya, Shinsuke Miyazaki, Takatsugu Kajiyama, Tomonori Watanabe, Shigeki Kusa, Hiroaki Nakamura, Hitoshi Hachiya, Yoshito Iesaka
BACKGROUND: Clinical utility of irrigation-tip ablation catheters for cavo-tricuspid isthmus (CTI) ablation is established. Recently, new-generation enhanced-cooling irrigation-tip catheters were introduced into clinical use. This study compared the performance of different types of novel irrigation-tip catheters in CTI ablation. METHODS: One hundred patients undergoing CTI ablation with novel irrigated-tip catheters were included. Ablation was performed with a power output of 30-35W using either 4-mm flexible tip catheters [FlexAbility (FAs) St...
November 24, 2017: Journal of Cardiology
Ponnusamy Nandhakumar, Byeongyoon Kim, Nam-Sihk Lee, Young Ho Yoon, Kwangyeol Lee, Haesik Yang
Enzyme-like nanocatalytic reactions developed for high signal amplification in biosensors are of limited use because of their low reaction rates and/or unwanted side reactions in aqueous electrolyte solutions containing dissolved O2. Herein, we report a nitrosoreductase-like catalytic reaction, employing 4-nitroso-1-naphthol, Pd nanoparticles, and H3N-BH3, which affords a high reaction rate and minimal side reactions, enabling its use in ultrasensitive electrochemical biosensors. 4-Nitroso-1-naphthol was chosen after five hydroxy-nitro(so)arene compounds were compared in terms of high signal and low background levels...
December 14, 2017: Analytical Chemistry
Marta Sanmartí-Espinal, Patrizia Iavicoli, Annalisa Calò, Marta Taulés, Roger Galve, M Pilar Marco, Josep Samitier
This study aims to improve our understanding of the interaction between olfactory receptors and odorants to develop highly selective biosensing devices. Natural nanovesicles (NVs) from Saccharomyces cerevisiae, ~100 nm in diameter, carrying either the human OR17-40 or the chimpanzee OR7D4 olfactory receptor (OR) tagged with the c-myc epitope at their N-terminus, are presented as model systems to quantify the interaction between odorant and olfactory receptors. The level of expression of olfactory receptors was determined at individual NVs using a novel competitive ELISA immunoassay comparing the values obtained against those from techniques involving the solubilization of cell membrane proteins and the identification of c-myc-carrying receptors...
December 13, 2017: Scientific Reports
Wenli Gao, Haohan Song, Xiao Wang, Xiaoqiang Liu, Xiaobin Pang, Yanmei Zhou, Bin Gao, Xiaojun Peng
Red emissive carbon dots (CDs) have drawn more and more attention due to their good organ penetration depth and slight biological tissues photodamage. Herein, the fluorescent CDs with red emission were synthesized by facile one-pot hydrothermal treatment of citric acid and neutral red, and they show red fluorescence both in aqueous solution and solid state. The solution of CDs exhibits the quantum yield (QY) of 12.1%, good stability against photobleaching, and low cytotoxicity. As-prepared CDs can be used as fluorescent probe for peculiar detection of Pt2+, Au3+ and Pd2+...
December 13, 2017: ACS Applied Materials & Interfaces
Zhengyun Wang, Shuang Dong, Mengxi Gui, Muhammad Asif, Wei Wang, Feng Wang, Hongfang Liu
Flexible sweat biosensors are of considerable current interest for the development of wearable smart miniature devices. In this work, we report a novel type of flexible and electrochemical sweat platform fabricated by depositing Cu submicron buds on freestanding graphene paper (GP) carrying MoS2 nanocrystals monolayer for bio-functional detection of glucose and lactate. Quantitative analysis of glucose and lactate was carried out by using amperometric i-t method. Linear ranges were obtained between 5 and 1775 μM for glucose and 0...
December 9, 2017: Analytical Biochemistry
Abdulhalim Kılıç, Fatma Nese Kok
Quartz crystal microbalance with dissipation (QCM-D) is one of the powerful techniques, which allow real time, quantitative and noninvasive analysis of the interaction of different cell types with various modified surfaces. In this study, the dynamic adhesion behavior of human fetal osteoblastic bone (hfOB) cell lines was first monitored on untreated and hydrophilically treated gold sensor surfaces as reference substrates. Adhesion was also observed under light microscopy to facilitate the evaluation. Cells increased their surface contact area and spread more on hydrophilic surfaces, and showed distinct profile with an increased rigidity at the interfacial layer, which is assigned to extracellular matrix remodeling...
December 12, 2017: Biointerphases
Chunsheng Wu, Ya-Wen Du, Liquan Huang, Yaron Ben-Shoshan Galeczki, Ayana Dagan-Wiener, Michael Naim, Masha Y Niv, Ping Wang
Taste and smell are very important chemical senses that provide indispensable information on food quality, potential mates and potential danger. In recent decades, much progress has been achieved regarding the underlying molecular and cellular mechanisms of taste and odor senses. Recently, biosensors have been developed for detecting odorants and tastants as well as for studying ligand-receptor interactions. This review summarizes the currently available biosensing approaches, which can be classified into two main categories: in vitro and in vivo approaches...
December 11, 2017: Sensors
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
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