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Eric W Recktenwald, Elizabeth A Dudkin, Laura K Skorina, William M Saidel, Edward R Gruberg
The amphibian retina projects to two discrete regions of neuropil in the anterior thalamus: the neuropil of Bellonci and the corpus geniculatum. These retinorecipient areas are encompassed within a larger zone of surrounding neuropil we call the NCZ (for neuropil of Bellonci/corpus geniculatum zone). The NCZ is characterized electrophysiologically by a distinctive tonic oscillatory response to blue light; it appears to be a visual module involved in processing the stationary visual environment. Using horseradish peroxidase (HRP), we mapped the connections of the NCZ...
November 16, 2017: Brain, Behavior and Evolution
Fang He, Hui Liu, Xinggang Guo, Bin-Cheng Yin, Bang-Ce Ye
Exosomes, as an important subpopulation of extracellular vesicles (EVs), play an important role in intercellular communications in various important pathophysiological processes, especially cancer-related. However, reliable and convenient quantitative methods for their determination are still technically challenging. In this study, we developed an efficient and direct method by combining immunoaffinity and lipid membrane surface modification into a single platform for specific isolation and accurate quantification of exosomes...
November 15, 2017: Analytical Chemistry
G Coussot, C Faye, A Le Postollec, M Dobrijevic
Antibody-coated surfaces (Ab surfaces) play a key role in bioanalytical tools developed for biosensors and diagnostics. Therefore, a high and well-defined functional activity of the Ab surface is required. The functional activity of the Ab surface depends on its available binding sites i.e. "the active sites" that are able to capture antigen (Ag). The number of active binding sites strongly depends on the immobilization strategy used to fix the Ab on the solid surface. Determination of layer thickness or surface topology are often used to characterize the Ab surfaces but there is no gold standard method for the study of the functionality of the Ab surfaces...
February 1, 2018: Talanta
Lucia Cenci, Chiara Piotto, Paolo Bettotti, Alessandra Maria Bossi
Nanosized Molecularly Imprinted Polymers (nanoMIPs) are designed artificial nanoreceptors with a predetermined selectivity and specificity for a given analyte, lately proposed as a replacement to antibodies in immunoassays. The nanoMIP-plate preparation based on nanoparticle adsorption was studied with the aim to rationally identify and discuss the critical points in the nanoMIP-assay development, in an example based on the iron homeostasis biomarker hepcidin and hepcidin-specific nanoMIPs (Kd = 9nM). Plates were prepared by deposition and drying of nanoMIP (0...
February 1, 2018: Talanta
Siddharth Deshpande, Nihar D Masurkar, Vallerinteavide Mavelli Girish, Malan Desai, Goutam Chakraborty, Juliana M Chan, Chester L Drum
The expression and stabilization of recombinant proteins is fundamental to basic and applied biology. Here we have engineered a thermostable protein nanoparticle (tES) to improve both expression and stabilization of recombinant proteins using this technology. tES provides steric accommodation and charge complementation to green fluorescent protein (GFPuv), horseradish peroxidase (HRPc), and Renilla luciferase (rLuc), improving the yields of functional in vitro folding by ~100-fold. Encapsulated enzymes retain the ability to metabolize small-molecule substrates, presumably via four 4...
November 13, 2017: Nature Communications
Muhammad Zahid Anwar, Dong Jun Kim, Ashok Kumar, Sanjay K S Patel, Sachin Otari, Primata Mardina, Jae-Hoon Jeong, Jung-Hoon Sohn, Jong Hak Kim, Jung Tae Park, Jung-Kul Lee
A major challenge in the industrial use of enzymes is maintaining their stability at elevated temperatures and in harsh organic solvents. In order to address this issue, we investigated the use of nanotubes as a support material for the immobilization and stabilization of enzymes in this work. SnO2 hollow nanotubes with a high surface area were synthesized by electrospinning the SnCl2 precursor and polyvinylpyrrolidone (dissolved in dimethyl formamide and ethanol). The electrospun product was used for the covalent immobilization of enzymes such as lipase, horseradish peroxidase, and glucose oxidase...
November 10, 2017: Scientific Reports
Lifang Chang, Haocheng Wu, Xiwen He, Langxing Chen, Yukui Zhang
A simple fluorescence turn-on sensor has been designed for the highly sensitive detection of glycoproteins on the basis of boronic acid functional polymer capped Mn-doped ZnS quantum dots (QDs@MPS@AAPBA). In the absence of glycoproteins, the fluorescence emission intensity of the QDs@MPS@AAPBA was relatively weaker due to the effective electronic transfer from the QDs to the boron moieties on its surface. While the glycoproteins were introduced into the system, an obvious fluorescence enhancement was observed...
December 1, 2017: Analytica Chimica Acta
Jie Wei, Aori Qileng, Yun Yan, Hongtao Lei, Shengsen Zhang, Weipeng Liu, Yingju Liu
An ultrasensitive photoelectrochemical (PEC) immunoassay based on multiple signal amplification strategy was fabricated for the detection of microcystin-LR (MC-LR). The CdS/TiO2 nanorod arrays (CdS/TiO2 NRAs) modified FTO electrode, which can weaken the self-oxidation by photogenerated holes of CdS nanoparticles, and limit the recombination of electron-hole pairs and broaden optical absorption of TiO2 NRAs, was used as a visible-light driven material to immobilize antigens. Then, Fe3O4 nanoparticles/polydopamine (Fe3O4@PDA) was used as the carrier to load secondary antibody (Ab2) and horseradish peroxidase (HRP), where Fe3O4 nanoparticles and HRP can synergistically accelerate the oxidation of 4-chloro-1-naphthol (4-CN) by H2O2 to produce biocatalytic precipitation (BCP) on the surface of modified electrode...
November 22, 2017: Analytica Chimica Acta
Eva Vargas, Rebeca M Torrente-Rodríguez, Víctor Ruiz-Valdepeñas Montiel, Eloy Povedano, María Pedrero, Juan J Montoya, Susana Campuzano, José M Pingarrón
This work describes a sensitive amperometric magneto-biosensor for single-step and rapid determination of microRNAs (miRNAs). The developed strategy involves the use of direct hybridization of the target miRNA (miRNA-21) with a specific biotinylated DNA probe immobilized on streptavidin-modified magnetic beads (MBs), and labeling of the resulting heteroduplexes with a specific DNA-RNA antibody and the bacterial protein A (ProtA) conjugated with an horseradish peroxidase (HRP) homopolymer (Poly-HRP40) as an enzymatic label for signal amplification...
November 9, 2017: International Journal of Molecular Sciences
James Nicholas Vranish, Mario G Ancona, Scott A Walper, Igor L Medintz
The growing emphasis on green chemistry, renewable resources, synthetic biology, regio-/stereospecific chemical transformations, and nanotechnology for providing new biological products and therapeutics is reinvigorating research into enzymatic catalysis. Although the promise is profound, many complex issues remain to be addressed before this effort will have a significant impact. Prime among these is to combat the degradation of enzymes frequently seen in ex vivo formats following immobilization to stabilize the enzymes for long-term application and to find ways of enhancing their activity...
November 8, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Manabu Nakazono, Shinkoh Nanbu
Enhancement effect on the chemiluminescence of acridinium ester derivatives under neutral conditions was investigated. Additions of phenols did not enhance the chemiluminescence intensities of acridinium ester derivatives in the presence of horseradish peroxidase and hydrogen peroxide. Additions of cetyltrimethylammonium bromide apparently enhanced the chemiluminescence intensities of phenyl 10-methyl-10λ(4) -acridine-9-carboxylate derivatives with electron-withdrawing groups at the 4-position of the phenyl group...
November 8, 2017: Luminescence: the Journal of Biological and Chemical Luminescence
Xiao Liu, Wei Qi, Yuefei Wang, Rongxin Su, Zhimin He
Metal-organic frameworks (MOFs) have drawn extensive research interest as candidates for enzyme immobilization owing to their tunable porosity, high surface area, and excellent chemical/thermal stability. Herein, we report a facile and universal strategy for enzyme immobilization using highly stable hierarchically porous metal-organic frameworks (HP-MOFs). The HP-MOFs were stable over a wide pH range (pH = 2-11 for HP-DUT-5) and met the catalysis conditions of most enzymes. The as-prepared hierarchical micro/mesoporous MOFs with mesoporous defects showed a superior adsorption capacity towards enzymes...
November 16, 2017: Nanoscale
Thai Thanh Hoang Thi, Yunki Lee, Seung Bae Ryu, Dai Hai Nguyen, Ki Dong Park
Development of bioadhesives with tunable mechanical strength, high adhesiveness, biocompatibility, and injectability is greatly desirable in all surgeries to replace or complement the sutures and staples. Herein, the dual catalytic activity of horseradish peroxidase is exploited to in situ form the hydroxyphenyl propionic acid-gelatin/thiolated gelatin (GH/GS) adhesive hydrogels including two alternative crosslinks (phenol-phenol and disulfide bonds) with fast gelation (few seconds - several minutes) and improved physicochemical properties...
November 6, 2017: Biopolymers
Yaofeng Zhou, Xiaolin Huang, Wenjing Zhang, Yanwei Ji, Rui Chen, Yonghua Xiong
Here, we for the first time used a thiolated amino-ligand modified multi-branched gold nanoflower as skeleton to encapsulate iron porphyrins (AuNF@FeTPPCl) as alternatives to horseradish peroxidase (HRP). After the FeTPPCl encapsulation, the HRP mimicking activity of FeTPPCl was effectively blocked by the steric hindrance of the hydrophobic layer on the AuNF surface. Upon the addition of ethanol, the loaded FeTPPCl was released into the solution in its free format and exposed the catalytic sites, resulting in the recovery of catalytic activity...
November 1, 2017: Biosensors & Bioelectronics
Meiling Lian, Liang Xu, Xiaowen Zhu, Xu Chen, Wensheng Yang, Tie Wang
This study demonstrates a new strategy for the development of a three-dimensional (3D) cell culture model-based cellular biosensing system. Distinctly different from the previously reported layering or separating fabrication of cell culture and sensing devices, herein living cells and enzymes as sensing elements are immobilized into a dipeptide-derived hydrogel matrix through simple one-pot self-assembly. The cells are then 3D cultured in the functional hydrogel, and the releasing superoxide anion (O2•‒) is detected in situ by a cascade superoxide dismutase and horseradish peroxidase-based electrochemical biosensor...
November 3, 2017: Analytical Chemistry
Amin Zhang, Weiwei Guo, Hong Ke, Xin Zhang, Huan Zhang, Chusen Huang, Dapeng Yang, Nengqin Jia, Daxiang Cui
A sandwich-configuration electrochemiluminescence (ECL) immunosensor based on Au star@BSA-Luminol nanocomposites for ultrasensitive determination of human chorionic gonadotropin (HCG) has been developed. In this work, nanostructured Polyaniline hydrogels (Pani) decorated with Pt nanoparticles (Pani/Pt) were utilized to construct the base of this immunosensor, greatly increasing the amount of loaded capture antibodies (Ab1) via linkage reagent glutaraldehyde (GA). The used conducting Pani/Pt nanocomposites possessed the unique features, such as large surface area, high electron transfer speed and favorable electrocatalytic activities of hydrogen peroxide, which offered a prominent platform for this sandwich-sensor and acted as efficient ECL signal amplifier also...
October 18, 2017: Biosensors & Bioelectronics
Christopher I Olivares, Camila L Madeira, Reyes Sierra-Alvarez, Warren Kadoya, Leif Abrell, Jon Chorover, Jim A Field
2,4-dinitrosanisole (DNAN) is an insensitive munitions component that is replacing conventional explosives. While DNAN is known to biotransform in soils to aromatic amines and azo-dimers, it is seldom mineralized by indigenous soil bacteria. Incorporation of DNAN biotransformation products into soil as humus-bound material could serve as a plausible remediation strategy. The present work studied DNAN biotransformation in (14)C-ring labeled soil and sludge microcosms to quantify the distribution of label in soil, aqueous, and gaseous phases...
October 26, 2017: Environmental Science & Technology
W Michael Panneton, BingBing Pan, Qi Gan
The somatotopy of the trigeminocervical complex of the rat was defined as a basis for describing circuitry for reflex behaviors directed through the facial motor nucleus. Thus, transganglionic transport of horseradish peroxidase conjugates applied to individual nerves/peripheral receptive fields showed that nerves innervating oropharyngeal structures projected most rostrally, followed by nerves innervating snout, periocular, and then periauricular receptive fields most caudally. Nerves innervating mucosae or glabrous receptive fields terminated densely in laminae I, II, and V of the trigeminocervical complex, while those innervating hairy skin terminated in laminae I-V...
2017: Frontiers in Neurology
Josune J Ezenarro, Naroa Uria, Óscar Castillo-Fernández, Noemí Párraga, Miquel Sabrià, Francesc Xavier Muñoz Pascual
The microbial quality of water is a key aspect to avoid environmental and public health problems. The low pathogen concentration needed to produce a disease outbreak makes it essential to process large water volumes and use sensitive and specific methods such as immunoassays for its detection. In the present work, we describe the development of a device based on microfiltration membranes to integrate the concentration and the immunodetection of waterborne bacteria. A microfiltration membrane treatment protocol was designed to reduce the non-specific binding of antibodies, for which different blocking agents were tested...
October 23, 2017: Analytical and Bioanalytical Chemistry
Haitang Yang, Anran Liu, Min Wei, Yuanjian Liu, Bingjing Lv, Wei Wei, Yuanjian Zhang, Songqin Liu
Early diagnosis and life-long surveillance are clinically important to improve the long-term survival of cancer patients. Telomerase activity is a valuable biomarker for cancer diagnosis but its measurement often used complex label procedures. Herein, we designed a novel, simple, visual and label-free method for telomerase detection by using enzymatic etching of gold nanorods (GNRs). Firstly, repeating (TTAGGG)x sequences were extented on telomerase substrate (TS) primer. It formed G-quadruplex under the help of Hemin and K+...
October 24, 2017: Analytical Chemistry
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