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https://www.readbyqxmd.com/read/28651110/inhibitory-assay-for-degradation-of-collagen-iv-by-cathepsin-b-with-a-surface-plasmon-resonance-sensor
#1
Atsushi Shoji, Yumiko Suenaga, Atsushi Hosaka, Yuuki Ishida, Akio Yanagida, Masao Sugawara
We describe a simple method for evaluating the inhibition of collagen IV degradation by cathepsin B with a surface plasmon resonance (SPR) biosensor. The change in the SPR signal decreased with an increase in the concentration of cathepsin B inhibitors. The order of the inhibitory constant (Ki) obtained by the SPR method was CA074Me≈Z-Phe-Phe-FMK < leupeptin. This order was different from that obtained by benzyloxycarbonyl-Phe-Phe-Fluoromethylketone (Z-Phe-Phe-FMK) as a peptide substrate. The comparison of Ki suggested that CA074 and Z-Phe-Phe-FMK inhibited exopeptidase activity, and leupeptin inhibited the endopeptidase activity of cathepsin B more strongly...
June 15, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28650030/carbon-nanoscroll-silk-crystallite-hybrid-structures-with-controllable-hydration-and-mechanical-properties
#2
Yuan Cheng, Leng-Duei Koh, Fan Wang, Dechang Li, Baohua Ji, Jingjie Yeo, Guijian Guan, Ming-Yong Han, Yong-Wei Zhang
Hybrid structures of nanomaterials (e.g. tubes, scrolls, threads, cages) and biomaterials (e.g. proteins) hold tremendous potential for applications as drug carriers, biosensors, tissue scaffolds, cancer therapeutic agents, etc. However, in many cases, the interacting forces at the nano-bio interfaces and their roles in controlling the structures and dynamics of nano-bio-hybrid systems are very complicated but poorly understood. In this study, we investigate the structure and mechanical behavior of a protein-based hybrid structure, i...
June 26, 2017: Nanoscale
https://www.readbyqxmd.com/read/28649845/multifunctional-nanostructured-conductive-polymer-gels-synthesis-properties-and-applications
#3
Fei Zhao, Ye Shi, Lijia Pan, Guihua Yu
Conductive polymers have attracted significant interest over the past few decades because they synergize the advantageous features of conventional polymeric materials and organic conductors. With rationally designed nanostructures, conductive polymers can further exhibit exceptional mechanical, electrical, and optical properties because of their confined dimensions at the nanoscale level. Among various nanostructured conductive polymers, conductive polymer gels (CPGs) with synthetically tunable hierarchical 3D network structures show great potential for a wide range of applications, such as bioelectronics, and energy storage/conversion devices owing to their structural features...
June 26, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28649484/enhancing-the-angular-sensitivity-of-plasmonic-sensors-using-hyperbolic-metamaterials
#4
Kandammathe Valiyaveedu Sreekanth, Yunus Alapan, Mohamed ElKabbash, Amy M Wen, Efe Ilker, Michael Hinczewski, Umut A Gurkan, Nicole F Steinmetz, Giuseppe Strangi
Surface plasmon resonance (SPR) sensors operate mainly on prism and grating coupling techniques, with spectral and angular scans being the two major interrogation schemes. Among them, the angular scan technique has several advantages including higher measurement precision owing to its higher signal-to-noise ratio. The currently available SPR sensor arrangements provide a maximum angular sensitivity of 500°-600° per RIU. Here, we report the study of grating coupled-hyperbolic metamaterial (GC-HMM) sensors with high angular sensitivity...
November 2016: Advanced Optical Materials
https://www.readbyqxmd.com/read/28649245/camelid-single-domain-antibodies-as-an-alternative-to-overcome-challenges-related-to-the-prevention-detection-and-control-of-neglected-tropical-diseases
#5
REVIEW
Carla F C Fernandes, Soraya Dos S Pereira, Marcos B Luiz, Juliana P Zuliani, Gilvan P Furtado, Rodrigo G Stabeli
Due mainly to properties such as high affinity and antigen specificity, antibodies have become important tools for biomedical research, diagnosis, and treatment of several human diseases. When the objective is to administer them for therapy, strategies are used to reduce the heterologous protein immunogenicity and to improve pharmacokinetic and pharmacodynamic characteristics. Size minimization contributes to ameliorate these characteristics, while preserving the antigen-antibody interaction site. Since the discovery that camelids produce functional antibodies devoid of light chains, studies have proposed the use of single domains for biosensors, monitoring and treatment of tumors, therapies for inflammatory and neurodegenerative diseases, drug delivery, or passive immunotherapy...
2017: Frontiers in Immunology
https://www.readbyqxmd.com/read/28649149/quantitative-imaging-of-cell-membrane-associated-effective-mass-density-using-photonic-crystal-enhanced-microscopy-pcem
#6
Yue Zhuo, Ji Sun Choi, Thibault Marin, Hojeong Yu, Brendan A Harley, Brian T Cunningham
Adhesion is a critical cellular process that contributes to migration, apoptosis, differentiation, and division. It is followed by the redistribution of cellular materials at the cell membrane or at the cell-surface interface for cells interacting with surfaces, such as basement membranes. Dynamic and quantitative tracking of changes in cell adhesion mass redistribution is challenging because cells are rapidly moving, inhomogeneous, and nonequilibrium objects, whose physical and mechanical properties are difficult to measure or predict...
November 2016: Prog Quantum Electron
https://www.readbyqxmd.com/read/28648096/nad-h-and-nadp-h-redox-couples-and-cellular-energy-metabolism
#7
Wusheng Xiao, Rui-Sheng Wang, Diane E Handy, Joseph Loscalzo
SIGNIFICANCE: The NAD+/NADH and NADP+/NADPH redox couples are essential for maintaining cellular redox homeostasis and for modulating numerous biological events, including cellular metabolism. Deficiency or imbalance of these two redox couples has been associated with many pathological disorders. Recent Advances: Newly-identified biosynthetic enzymes and newly-developed genetically encoded biosensors enable us to understand better how cells maintain compartmentalized NAD(H) and NADP(H) pools...
June 24, 2017: Antioxidants & Redox Signaling
https://www.readbyqxmd.com/read/28647645/adding-dimension-to-cellular-mechanotransduction-advances-in-biomedical-engineering-of-multiaxial-cell-stretch-systems-and-their-application-to-cardiovascular-biomechanics-and-mechano-signaling
#8
REVIEW
O Friedrich, D Schneidereit, Y A Nikolaev, V Nikolova-Krstevski, S Schürmann, A Wirth-Hücking, A L Merten, D Fatkin, B Martinac
Hollow organs (e.g. heart) experience pressure-induced mechanical wall stress sensed by molecular mechano-biosensors, including mechanosensitive ion channels, to translate into intracellular signaling. For direct mechanistic studies, stretch devices to apply defined extensions to cells adhered to elastomeric membranes have stimulated mechanotransduction research. However, most engineered systems only exploit unilateral cellular stretch. In addition, it is often taken for granted that stretch applied by hardware translates 1:1 to the cell membrane...
June 21, 2017: Progress in Biophysics and Molecular Biology
https://www.readbyqxmd.com/read/28647589/mannose-conjugated-layered-double-hydroxide-nanocomposite-for-targeted-sirna-delivery-to-enhanced-cancer-therapy
#9
Li Li, Run Zhang, Wenyi Gu, Zhi Ping Xu
Sheet-like layered double hydroxide nanoparticles (LDH NPs) have showed great potentials in biomedical applications such as nanocarriers for drug and gene delivery, biosensors and imaging agents. However, target delivery of drugs and genes using LDH NPs to the desired tumor sites is a major challenge in cancer therapy. The aim of this study is to develop a functional LDH-based nanocomposite for target delivery of siRNA to cancer cells. Mannose as a targeting moiety was firstly conjugated onto SiO2-coated LDH nanocomposite...
June 21, 2017: Nanomedicine: Nanotechnology, Biology, and Medicine
https://www.readbyqxmd.com/read/28647530/measuring-kinetic-rate-constants-of-multiple-component-reactions-with-optical-biosensors
#10
David A Edwards, Ryan M Evans, Wenbin Li
One may measure the kinetic rate constants associated with biochemical reactions using an optical biosensor: an instrument in which ligand molecules are convected through a flow cell over a surface to which receptors are immobilized. If there are multiple reactants, one is faced with the problem of fitting multiple kinetic rate constants to one signal, since data from all of the reacting species is lumped together. Even in the presence of ambiguous data, one may use a series of experiments to accurately determine the rate constants...
June 21, 2017: Analytical Biochemistry
https://www.readbyqxmd.com/read/28646721/biochemical-immunological-hybrid-biosensor-based-on-two-dimensional-chromatography-for-on-site-sepsis-diagnosis
#11
Seung-Wan Kim, Il-Hoon Cho, Guei-Sam Lim, Gi-Na Park, Se-Hwan Paek
A hybrid-biosensor system that can simultaneously fulfill the immunoassay for protein markers (e.g., C-reactive protein (CRP) and procalcitonin (PCT)) and the enzyme assay for metabolic substances (e.g., lactate) in the same sepsis-based sample has been devised. Such a challenge was pursued through the installation of an enzyme-reaction zone on the signal pad of the typical immuno-strip for the rapid two-dimensional (2-D)-chromatography test. To minimize the mutual interference in the hybrid assays, a pre-determined membrane site was etched in a pattern and mounted with a biochemical-reaction pad, thereby allowing a loaded sample to enter and then stay in the pad for a colored-signal production over the course of an immunoassay...
June 16, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28646720/nanoporous-gold-based-microbial-biosensor-for-direct-determination-of-sulfide
#12
Zhuang Liu, Hanyue Ma, Huihui Sun, Rui Gao, Honglei Liu, Xia Wang, Ping Xu, Luying Xun
Environmental pollution caused by sulfide compounds has become a major problem for public health. Hence, there is an urgent need to explore a sensitive, selective, and simple sulfide detection method for environmental monitoring and protection. Here, a novel microbial biosensor was developed using recombinant Escherichia coli BL21 (E. coli BL21) expressing sulfide:quinone oxidoreductase (SQR) for sulfide detection. As an important enzyme involved in the initial step of sulfide metabolism, SQR oxidizes sulfides to polysulfides and transfers electrons to the electron transport chain...
June 20, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28646144/using-fractional-intensities-of-time-resolved-fluorescence-to-sensitively-quantify-nadh-nad-with-genetically-encoded-fluorescent-biosensors
#13
Mengfang Chang, Lei Li, Hanyang Hu, Qingxun Hu, Aoxue Wang, Xiaodan Cao, Xiantong Yu, Sanjun Zhang, Yuzheng Zhao, Jinquan Chen, Yi Yang, Jianhua Xu
In this paper, we propose a novel and sensitive ratiometric analysis method that uses the fractional intensities of time-resolved fluorescence of genetically encoded fluorescent NADH/NAD(+) biosensors, Peredox, SoNar, and Frex. When the conformations of the biosensors change upon NADH/NAD(+) binding, the fractional intensities (α i τ i ) have opposite changing trends. Their ratios could be exploited to quantify NADH/NAD(+) levels with a larger dynamic range and higher resolution versus commonly used fluorescence intensity and lifetime methods...
June 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28645004/amplified-detection-of-hepatitis-b-virus-using-an-electrochemical-dna-biosensor-on-a-nanoporous-gold-platform
#14
Laleh Enayati Ahangar, Masoud A Mehrgardi
In the present study, a nanoporous gold platform was applied for the amplified detection of Hepatitis B virus (HBV) by an electrochemical DNA biosensor. Ferrocene as a redox reporter was covalently attached to the DNA probe and its electrochemical signal was recorded as the biosensor response. For real samples, DNA was firstly extracted from blood of patients and then amplified by polymerase chain reaction (PCR) for 5cycles. Sensitivity of this biosensor was enhanced by using nanoporous gold electrode, therefore this sensor can discriminate the genome of HBV in real sample with low PCR cycles...
June 15, 2017: Bioelectrochemistry
https://www.readbyqxmd.com/read/28644494/feco-nanoparticles-embedded-carbon-nanofibers-as-robust-peroxidase-mimics-for-sensitive-colorimetric-detection-of-l-cysteine
#15
Zezhou Yang, Yun Zhu, Guangdi Nie, Meixuan Li, Ce Wang, Xiaofeng Lu
A simple and low cost detection of l-cysteine is essential in the fields of biosensors and medical diagnosis. In this study, we have developed a simple electrospinning, followed by calcination process to prepare FeCo nanoparticles embedded in carbon nanofibers (FeCo-CNFs) as an efficient peroxidase-like mimic for the detection of l-cysteine. FeCo nanoparticles are uniformly dispersed within CNFs, and their diameters are highly influenced by the calcination temperature. The calcination temperature also influences the peroxidase-like catalytic activity, and the maximum activity is achieved at a calcination temperature of 550 °C...
June 23, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28644401/the-investigation-of-electrochemistry-behaviors-of-tyrosinase-based-on-directly-electrodeposited-grapheneon-choline-gold-nanoparticles
#16
Yaping He, Xiaohui Yang, Quan Han, Jianbin Zheng
A novel catechol (CA) biosensor was developed by embedding tyrosinase (Tyr) onto in situ electrochemical reduction graphene (EGR) on choline-functionalized gold nanoparticle (AuNPs-Ch) film. The results of UV-Vis spectra indicated that Tyr retained its original structure in the film, and an electrochemical investigation of the biosensor showed a pair of well-defined, quasi-reversible redox peaks with Epa = -0.0744 V and Epc = -0.114 V (vs. SCE) in 0.1 M, pH 7.0 sodium phosphate-buffered saline at a scan rate of 100 mV/s...
June 23, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28643851/fluorescent-competitive-aptasensor-for-detection-of-aflatoxin-b1
#17
Monali Mukherjee, Praveena Bhatt, Manonmani H K
Aflatoxin B1 (AFB1 ) is one of the most commonly found mycotoxins in food commodities, particularly cereals, oilseeds, spices and tree nuts. In the past decade, aptamers have come into limelight and emerged as a new biosensing element replacing antibodies in various detection formats. Herein we report a faster, more sensitive, high throughput method for the detection of AFB1 using AFB1 -specific aptamers. The assay format was based on a competitive reaction of the fluorescent tagged aptamer specific to AFB1 with the aflatoxin conjugate...
June 23, 2017: Journal of Molecular Recognition: JMR
https://www.readbyqxmd.com/read/28643445/a-novel-electrochemical-biosensor-with-dual-signal-outputs-toward-simultaneous-quantification-of-ph-and-o2-in-brain-upon-ischemia-and-in-tumor-during-cancer-therapy
#18
Li Liu, Fan Zhao, Wei Liu, Tong Zhu, Zh John Zhang, Chen Chen, Zhihui Dai, Huisheng Peng, Jun-Long Huang, Qin Hu, Wenbo Bu, Yang Tian
In this work, we develop a novel methodology for designing electrochemical biosensors with both current and potential signal outputs for simultaneous determination of two important species in the live systems. By designing a new molecule, Hemin-aminoferrocene (Hemin-Fc), we create a single electrochemical biosensor for simultaneous quantification of O2 and pH in brain upon ischemia and in tumor during cancer starvation therapy. The reduction peak current of Hemin group increases with rising concentrations of O2 from 1...
June 22, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28640952/label-free-dynamic-mass-redistribution-and-bio-impedance-methods-for-drug-discovery
#19
Manuel Grundmann
Label-free biosensors are increasingly employed in drug discovery. Cell-based biosensors provide valuable insights into the biological consequences of exposing cells and tissues to chemical agents and the underlying molecular mechanisms associated with these effects. Optical biosensors based on the detection of dynamic mass redistribution (DMR) and impedance biosensors using cellular dielectric spectroscopy (CDS) capture changes of the cytoskeleton of living cells in real time. Because signal transduction correlates with changes in cell morphology, DMR and CDS biosensors are exquisitely suited for recording integrated cell responses in an unbiased, yet pathway-specific manner without the use of labels that may interfere with cell function...
June 22, 2017: Current Protocols in Pharmacology
https://www.readbyqxmd.com/read/28640589/ru-bpy-32-incorporated-luminescent-polymer-dots-double-enhanced-electrochemiluminescence-for-detection-of-single-nucleotide-polymorphism
#20
Yaqiang Feng, Feng Sun, Ningning Wang, Jianping Lei, Huangxian Ju
Encapsulating a large amount of electrochemiluminescence (ECL) active molecules into one nanoparticle for single target recognition can greatly improve the sensitivity of ECL assay. This work used luminescent conjugated polymer as a carrier to synthesize Ru(bpy)32+ doped polymer dots (RuPdots). The RuPdots with an average size of 20 nm and encapsulation of about 1354 Ru(bpy)32+ showed greatly enhanced ECL emission. Using tripropylamine as a co-reactant, the resonance energy transfer from the excited polymer dots to the encapsulated Ru(bpy)32+ was demonstrated, which led to 15...
June 22, 2017: Analytical Chemistry
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