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Wenjing Wang, Huabiao Tang, Yuan Wu, Yinli Zhang, Zhaohui Li
A non-enzymatic and highly electrocatalytic H2 O2 biosensor was proposed by using a novel electrode composed of hemin-capped biomineralized gold nanoparticles (Hem@AuNPs), reduced graphene oxide (rGO) and chitosan (CS). Owing to the excellent electrocatalytic activity of Hem@AuNPs and great conductivity of rGO, this developed biosensor is capable of ultrasensitive measuring H2 O2 in real-time. In addition, the introduction of CS resulted in a film on the electrode, which can enhance the stability by protecting the biosensor from external disturbances...
February 21, 2019: Biosensors & Bioelectronics
Dahdjim B Betolngar, Élia Mota, Arne Fabritius, Jacob Nielsen, Charlotte Hougaard, Claus T Christoffersen, Jun Yang, Jan Kehler, Oliver Griesbeck, Liliana R V Castro, Pierre Vincent
The calcium-regulated phosphodiesterase 1 (PDE1) family is highly expressed in the brain, but its functional role in neurones is poorly understood. Using the selective PDE1 inhibitor Lu AF64196 and biosensors for cyclic nucleotides including a novel biosensor for cGMP, we analyzed the effect of PDE1 on cAMP and cGMP in individual neurones in brain slices from male newborn mice. Release of caged NMDA triggered a transient increase of intracellular calcium, which was associated with a decrease in cAMP and cGMP in medium spiny neurones in the striatum...
March 16, 2019: Cerebral Cortex
James C Charlesworth, Cara Watters, Hon Lun Wong, Pieter T Visscher, Brendan P Burns
Quorum sensing is a potent system of genetic control allowing phenotypes to be coordinated across localized communities. In this study, quorum sensing systems in Shark Bay microbial mats were delineated using a targeted approach analyzing whole mat extractions as well as the creation of an isolate library. A library of 165 isolates from different mat types were screened using the AHL biosensor E. coli MT102. Based on sequence identity 30 unique isolates belonging to Proteobacteria, Actinobacteria and Firmicutes were found to activate the AHL biosensor, suggesting AHLs or analogous compounds were potentially present...
March 16, 2019: FEMS Microbiology Ecology
A B Nurul Najian, Phiaw Chong Foo, Nabilah Ismail, Low Kim-Fatt, Chan Yean Yean
This study highlighted the performance of the developed integrated loop-mediated isothermal amplification (LAMP) coupled with a colorimetric DNA-based magnetogenosensor. The biosensor operates through a DNA hybridization system in which a specific designed probe captures the target LAMP amplicons. We demonstrated the magnetogenosensor assay by detecting pathogenic Leptospira, which causes leptospirosis. The color change of the assay from brown to blue indicated a positive result, whereas a negative result was indicated by the assay maintaining its brown color...
March 12, 2019: Molecular and Cellular Probes
Di Cheng, Yaping Zhang, Dongxiao Wen, Zhuangzhuang Guo, Huaixia Yang, Yanju Liu, Jinming Kong
A novel, simple, and label-free amplification electrochemical impedance method for quantitative detection of Human T-lymphotropic virus types II(HTLV-II) via click chemistry-mediated of hairpin DNA probes (hairpins) with polymers was developed. The hairpins were firstly attached to the gold electrode surface by an S-Au bond, the azido terminals of hairpins were close to the electrode surface, which make it difficult to be approached. After hybridizing with HTLV-II, the hairpins were unfolded and experienced a big configuration change, which made the azido terminals of the hairpins available to conjugate with alkynyl-containing polymer, called P(DEB-DSDA), formed by 1,4-diacetylenebenzene (DEB) and 4,4'-Diazido-2,2'-stilbenedisulfonic acid disodium salt tetrahydrate (DSDA) via Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC)...
June 20, 2019: Analytica Chimica Acta
Peng Zhao, Han-Xia Li, Da-Wei Li, Ya-Jun Hou, Leilei Mao, Mingfeng Yang, Ying Wang
Assay technologies capable of detecting biomarker concentrations in unprocessed whole blood samples are fundamental for applications in medical diagnostics. SERS nano-tags integrated magnetic-separation biosensor (MSB) was realized for the first time for immunoassay in whole blood. The reliability and sensitivity of this method rely, in a large extent, on the quality and properties of the SERS nano-tags. The constructed silicacoated Ag SERS nano-tags as labels were used in a rapid and specific MSB immune sensor to detect Matrix Metalloproteinases 9 (MMP-9) in unprocessed blood samples...
June 1, 2019: Talanta
Dawei Fan, Chunzhu Bao, Xin Liu, Jinhui Feng, Dan Wu, Hongmin Ma, Huan Wang, Qin Wei, Bin Du
A novel visible light photoelectrochemical immunosensor based on BiOBr/Bi2 S3 heterostructures was fabricated to detect squamous cell carcinoma antigen (SCCA). Bi2 S3 nanoparticles formed on the BiOBr microflowers by the self-sacrificial synthesis method based on the facile reaction between BiOBr and S2- ions. The BiOBr/Bi2 S3 composites exhibited excellent visible light photoelectrochemical activity, when ascorbic acid (AA) was employed as a perfect electron donor. The photocurrent intensity of BiOBr/Bi2 S3 modified ITO electrode arrived at around 20 µA, which was approximately 30 times than that of pure BiOBr...
June 1, 2019: Talanta
Lingwen Zeng, Junyu Gong, Peisen Rong, Chengshuai Liu, Junhua Chen
As an ubiquitous heavy metal pollutant, cadmium ion (Cd2+ ) is detrimental to food and human health even at low concentrations. Conventional methods require costly instruments and cannot meet the requirements of on-site analysis. Here we report the use of a personal glucose meter (PGM) as the point-of-use (POU) device for portable and quantitative detection of Cd2+ . The specific recognition between the aptamer and Cd2+ trigger the recycling signal amplification process by exonuclease III (Exo III). After successive hybridization and cleavage reactions, numerous single-stranded DNA were liberated on the surface of the magnetic bead...
June 1, 2019: Talanta
Nur-Fadhilah Mazlan, Ling Ling Tan, Nurul Huda Abd Karim, Lee Yook Heng, Nur Diyana Jamaluddin, Nurul Yuziana Mohd Yusof, Doris Huai Xia Quay, Bahariah Khalid
An optical genosensor based on Schiff base complex (Zn2+ salphen) DNA label and acrylic microspheres (AMs) as polymer support of the capturing DNA probe (cpDNA) was developed for dengue virus serotype 2 (DEN-2) detection via reflectance spectrophotometric method. The solid-state optical DNA biosensor showed high selectivity and specificity up to one-base mismatch in the target DNA sequence owing to the salphen chemical structure that is rich in localized electrons, and allowed π-π stacking interaction between stacked base pairs of double-stranded DNA (dsDNA)...
June 1, 2019: Talanta
Erhu Xiong, Deshuai Zhen, Ling Jiang
Nucleic acids-based biosensors are extremely important in modern life sciences and have been widely used for the detection of many biomarkers of disease and extensively applied in many fields, such as medical analysis, gene therapy, and pathogen determination. Therefore, it is necessary to develop some sensitive and selective methods for rapid detection of nucleic acids. In this work, an ultrasensitive and non-enzyme electrochemical biosensor has been developed for nucleic acids detection based on entropy-driven amplification (EDA) strategy and Mg2+ -dependent DNAzyme cleavage method...
June 1, 2019: Talanta
Pasquale Palladino, Alvaro Brittoli, Emanuela Pascale, Maria Minunni, Simona Scarano
We report a facile, low-cost and safe analytical method for estimation of total protein content, even in complex matrix like human serum, by exploiting the competition between proteins and polydopamine (PDA) for surface binding. The surface coating has been examined by using a microplate reader taking the advantage of the PDA absorbance in the visible region, obtaining new insights into the modelling of polydopamine deposition and polymer/protein adsorption competition. This is helpful for rational development of imprinted biosensors, and potentially offering a with broad applications ranging from diagnostic tools in medicine to food analysis...
June 1, 2019: Talanta
Ni Zeng, Juan Xiang
KRAS G12D point mutation plays an important role in the incidence of non-small-cell lung cancer (NSCLC) as well as colorectal cancer, pancreatic cancer and breast cancer. Here, we developed a novel anchor-like DNA (alDNA) electrochemical sensor for the detection of KRAS point mutation level (the concentration ratio of the specific KRAS point mutant DNA (M-DNA) to the total DNA (t-DNA) of both mutant and wild-type DNAs carrying the same allele). Compared to those conventional ligation-based DNA sensors, the proposed alDNA sensor achieved the one-step capture of both wild-type and mutant DNA, and the subsequent detection on one chip, which effectively decreased systematic errors from the uncertain differences on the interfacial structural and microenvironmental changes, improved the detection accuracy...
June 1, 2019: Talanta
Ana Lucia Campaña, Sergio Leonardo Florez, Mabel Juliana Noguera, Olga P Fuentes, Paola Ruiz Puentes, Juan C Cruz, Johann F Osma
Emerging water pollutants such as pharmaceutical contaminants are suspected to induce adverse effects to human health. These molecules became worrisome due to their increasingly high concentrations in surface waters. Despite this alarming situation, available data about actual concentrations in the environment is rather scarce, as it is not commonly monitored or regulated. This is aggravated even further by the absence of portable and reliable methods for their determination in the field. A promising way to tackle these issues is the use of enzyme-based and miniaturized biosensors for their electrochemical detection...
March 15, 2019: Biosensors
Xuan Weng, Yuejun Kang, Qian Guo, Bei Peng, Hai Jiang
Over the past decades, researchers have been seeking attractive substrate materials to keep microfluidics improving to outbalance the drawbacks and issues. Cellulose substrates, including thread, paper and hydrogels are alternatives due to their distinct structural and mechanical properties for a number of applications. Thread have gained considerable attention and become promising powerful tool due to its advantages over paper-based systems thus finds numerous applications in the development of diagnostic systems, smart bandages and tissue engineering...
March 8, 2019: Biosensors & Bioelectronics
Mengxing Ouyang, Dino Di Carlo
We demonstrate a swarm biosensing platform that detects analyte based on the change in plasmonic signal from thousands of single nanoparticles sensors, leading to increased quantitative accuracy. Following dark field microscopy, we perform computational image registration and analyses to compile the hue change from thousands of single gold nanoparticles acting as individual quantitative biosensors. This platform demonstrated a limit of detection of 10 pM with a dynamic range of at least 4 orders of magnitude in buffer solution, and the successful detection of c-reactive protein (CRP) in serum compatible with 3-tier clinical cutoffs within a 10-fold difference without the need for a blocking step...
March 4, 2019: Biosensors & Bioelectronics
Seiji Sakamoto, Shigeki Kiyonaka, Itaru Hamachi
Proteins as causative agents of diseases such as cancers, diabetes and neurological disorders are attractive drug targets. For developing chemicals selectively acting on key disease-causing proteins, one useful concept is the direct conversion of such target proteins into biosensors. This approach provides ligand-binding assay systems based on protein-based biosensors, which can quantitatively evaluate interactions between the protein and a specific ligand in many environments. Site-specific chemical modifications are used widely for the creation of protein-based semisynthetic biosensors in vitro...
March 12, 2019: Current Opinion in Chemical Biology
Seong Woo Moon, Ji Won Ha
Plasmonic gold nanoparticles can be an efficient source of hot electrons that can transfer to adsorbed molecules for photochemistry, followed by broadening of the homogeneous localized surface plasmon resonance (LSPR) linewidth. Although chemical interface damping (CID) is one of the main decay processes, it is the most poorly understood damping mechanism in gold nanoparticles. Herein, to better understand CID and to find new functional groups that can induce CID as an alternative to thiol groups (-SH, sulfhydryl groups), we carried out scanning electron microscopy (SEM) correlated dark-field (DF) scattering studies of gold nanorods (AuNRs) at the single-particle level...
March 15, 2019: Physical Chemistry Chemical Physics: PCCP
Kai Tong, Yunxuan Wang, Fucheng Wang, Jiaru Sun, Xiaogang Wu
A surface plasmon resonance biosensor based on a graphene-decorated grating excitation structure is proposed in this paper. The biosensor consists of a three-layer structure, including a graphene layer, a grating layer, and a high refractive index layer. The material of the grating layer is silica. The graphene is physically deposited on the grating ridges. An incident light with transverse magnetic polarization is used to excite surface plasmons in the mid-infrared spectral region, which is highly localized at both ends of the graphene layer...
March 1, 2019: Applied Optics
Seth L Ness, Abigail Bangerter, Nikolay V Manyakov, David Lewin, Matthew Boice, Andrew Skalkin, Shyla Jagannatha, Meenakshi Chatterjee, Geraldine Dawson, Matthew S Goodwin, Robert Hendren, Bennett Leventhal, Frederick Shic, Jean A Frazier, Yvette Janvier, Bryan H King, Judith S Miller, Christopher J Smith, Russell H Tobe, Gahan Pandina
Objective: The Janssen Autism Knowledge Engine (JAKE®) is a clinical research outcomes assessment system developed to more sensitively measure treatment outcomes and identify subpopulations in autism spectrum disorder (ASD). Here we describe JAKE and present results from its digital phenotyping (My JAKE) and biosensor (JAKE Sense) components. Methods: An observational, non-interventional, prospective study of JAKE in children and adults with ASD was conducted at nine sites in the United States. Feedback on JAKE usability was obtained from caregivers...
2019: Frontiers in Neuroscience
Jianyong Li, Xingping Liu, Yahui Man, Qian Chen, Di Pei, Wenjian Wu
Olfactory receptors (OR), a group of classic membrane proteins, plays a vital role in insect reproduction and acclimatization. Deciphering the molecular mechanism of insect olfaction could enhance pest control and environmental protection. Studies on ORs have faced a major bottleneck due to the notoriously strong hydrophobicity of ORs, which results in difficult expression in heterologous cell systems. Here, we demonstrated that insect ORs could be functionally produced using the E. coli cell-free protein synthesis system (CFPS), in which the highest yield of total ORs is 350 μg per 1 ml reaction...
March 11, 2019: Protein Expression and Purification
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