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Hyun-Kyung Oh, Ju-Wan Kim, Jae-Min Kim, Min-Gon Kim
Cortisol, a steroid hormone, is a main biomarker of psychological stress. Early diagnosis and proper treatment of such stress is crucial to prevent the excessive secretion of cortisol. However, cortisol has a low molecular weight and cannot provide sufficient recognition sites for sandwich immunoreaction; it has previously been measured using a competitive immunoassay instead of a general sandwich immunoassay. The disadvantage of this approach is that quantitative measurements are limited because of the narrow measurable range that is key for biosensors...
July 19, 2018: Analyst
Pablo Fagúndez, Gustavo Brañas, Ernesto Cairoli, Justo Laíz, Juan Pablo Tosar
Autoimmune diseases are chronic inflammatory pathologies that are characterized by the presence of antibodies against the body's own epitopes in serum (autoantibodies). Systemic lupus erythematosus (SLE) is a common autoimmune pathology characterized by the presence of antinuclear antibodies (ANAs). These include anti-dsDNA (α-dsDNA) antibodies, which are widely used for diagnosis and disease monitoring. Their determination is carried out using traditional techniques such as Indirect Immunofluorescence (IFI) or Enzyme-Linked Immunosorbent Assay (ELISA), which are time consuming, require qualified technicians, and are not compatible with decentralized analysis outside a laboratory facility...
July 18, 2018: Analyst
Grace E Florence, William J Gee
Two commercially-available terbium and europium complexes, EuFOD and TbTMHD, provide luminescent visualisation of latent fingermarks placed on nonporous surfaces via sublimation. This is demonstrated using UV radiation from a forensic light source. The method was optimised on metal foil, with other archetypal nonporous surfaces (i.e. glass, ceramic) also suited to this method.
July 17, 2018: Analyst
Chuanxia Chen, Qun Yuan, Pengjuan Ni, Yuanyuan Jiang, Zhenlu Zhao, Yizhong Lu
Alkaline phosphatase (ALP) is a significant biomarker for diagnostics. Simple, selective and sensitive detection of ALP activity is thus of critical importance. In this study, an artful fluorescence assay for ALP is proposed based on adenosine triphosphate (ATP) hydrolysis-triggered disassociation and fluorescence quenching of cerium coordination polymer nanoparticles (CPNs). ATP, a recognized natural substrate of phosphatase, can serve as a superb "antenna" to sensitize the luminescence of Ce3+ with the aid of tris(hydroxymethyl) aminomethane (Tris), forming Ce3+-ATP-Tris CPNs...
July 16, 2018: Analyst
Kamonchanok Phoonsawat, Nalin Ratnarathorn, Charles S Henry, Wijitar Dungchai
We report for the first time the development of a distance-based paper sensor for a simple, inexpensive, instrument-free, and portable determination of chloride ions. Our analysis reaction is based on the oxidative etching of silver nanoparticles (AgNPs) to form AgCl in the presence of Cl- and H2O2. H2O2 reacts with AgNPs in the channel of the paper device and Cl- in the sample forming a white precipitate (AgCl) where the white color band length is proportional to the Cl- concentration. Quantification of Cl- is achieved by measuring the length of the white color band using a ruler printed on the side of the channel...
July 16, 2018: Analyst
Bingqing Shui, Dan Tao, Jing Cheng, Yong Mei, Nicole Jaffrezic-Renault, Zhenzhong Guo
Tau protein plays a crucial role in the pathogenesis of Alzheimer's disease (AD). However, the assay to detect low concentrations of tau protein is a great challenge for the early diagnosis of AD. We will outline a novel aptamer-antibody sandwich assay based on an electrochemical biosensor for the detection of tau-381 in human serum. To improve the detection sensitivity, the aptamer-antibody sandwich assay for the detection of tau-381 was developed by using a tau antibody (anti-tau) and an aptamer specific to tau-381 as the recognition element and cysteamine-stabilized gold nanoparticles (AuNPs) for signal amplification...
July 13, 2018: Analyst
Marta I S Veríssimo, Sara B Oliveira, Nelson A F Silva, Manuel Matos, Amin Karmali, M Teresa S R Gomes
Pseudomonas aeruginosa (P. aeruginosa) possesses intracellular amidase activity, which catalyses the hydrolysis of short aliphatic amides producing NH4+, and has already been used along with an ammonium ion selective electrode for amide quantification. However, the incorporation of a biological membrane turned to be a challenging process and either the final arrangement was prone to amidase losses or the recovery of the sensor coating after the interaction took too long. In this article a flow injection system with an ammonium acoustic wave sensor is proposed, and after testing several different arrangements for the biological element, the ultimate choice consisted of the immobilization of a P...
July 13, 2018: Analyst
Phiranuphon Meksiarun, Pedro H B Aoki, Samantha J Van Nest, Regivaldo Gomes Sobral-Filho, Julian J Lum, Alexandre G Brolo, Andrew Jirasek
External beam radiotherapy is a common form of treatment for breast cancer. Among patients and across different breast cancer subtypes, the response to radiation is heterogeneous. Radiation-induced biochemical changes were examined by Raman spectroscopy using cell lines that represent a spectrum of human breast cancer. Principal component analysis (PCA) and partial least squares discriminant analysis (PLSDA) revealed unique Raman spectral features in the HER2 and Ki67 subtype. The changes in Raman spectral profiles to different doses of radiation (0-50 Gy) included variations in the levels of proteins, lipids, nucleic acids and glycogen...
July 13, 2018: Analyst
Jingfeng Wang, Yu Wang, Su Liu, Haiwang Wang, Xue Zhang, Xiaolei Song, Jiadong Huang
Uracil-DNA glycosylase (UDG) is a crucial damage repair enzyme that initiates the cellular base excision repair pathway that maintains the integrity of the genome. Abnormal UDG activity may induce the malfunction of uracil excision repair that is directly related to a range of diseases including cancers, genotypic diseases, and human immunodeficiencies. In this work, a simple, robust and cost effective biosensing platform for the ultrasensitive detection of UDG activity is established based on the combination of base excision repair-initiated primer generation for rolling circular amplification (RCA) with Endo IV-assisted signal amplification...
July 12, 2018: Analyst
Yuqiong Sun, Baoyin Yuan, Meitao Deng, Qing Wang, Jin Huang, Qiuping Guo, Jianbo Liu, Xiaohai Yang, Kemin Wang
Light-up aptamers have attracted growing attention due to their advantages of being label-free and having low fluorescence background. In this work, we developed a light-up fluorescence assay for label-free detection of tumor cells based on a bifunctional split aptamer (BFSA) that contained two DNA strands (BFSA-a and BFSA-b). BFSA-a and BFSA-b were constructed by combining aptamers ZY11 and ThT.2-2, which could specifically bind to the tumor cell SMMC-7721 and activate the fluorescence of thioflavin T (ThT)...
July 12, 2018: Analyst
Meegle S Mathew, Joyal Davis, Kuruvilla Joseph
Fluorescent copper quantum clusters (CuQCs) have received great interest in recent times due to their attractive features, such as water solubility, low cost, wide availability of Cu and good biocompatibility. Recently, considerable efforts have been devoted to the preparation and applications of CuQCs. Herein, we report a simple one-pot green method for the preparation of fluorescent CuQCs using a plant-derived protein, gluten, as a stabilizing agent. Gluten, a naturally abundant, low-cost and sustainable plant-protein derived from wheat, was employed both as a reducing and stabilizing agent to produce blue emitting CuQCs...
July 12, 2018: Analyst
Amélie St-Georges-Robillard, Mathieu Masse, Maxime Cahuzac, Mathias Strupler, Bishnubrata Patra, Adriana Mari Orimoto, Jennifer Kendall-Dupont, Benjamin Péant, Anne-Marie Mes-Masson, Frédéric Leblond, Thomas Gervais
Tumor spheroids represent a realistic 3D in vitro cancer model because they provide a missing link between monolayer cell culture and live tissues. While microfluidic chips can easily form and assay thousands of spheroids simultaneously, few commercial instruments are available to analyze this massive amount of data. Available techniques to measure spheroid response to external stimuli, such as confocal imaging and flow cytometry, are either not appropriate for 3D cultures, or destructive. We designed a wide-field hyperspectral imaging system to analyze multiple spheroids trapped in a microfluidic chip in a single acquisition...
July 12, 2018: Analyst
Vishal Kachwal, I S Vamsi Krishna, Leena Fageria, Jagrity Chaudhary, Ram Kinkar Roy, Rajdeep Chowdhury, Inamur Rahaman Laskar
In this article, we tried to redefine the unexplored potential of a benzothiazole type of Schiff-base (OM), which was identified as an AIE-active molecule that exhibits excited-state intramolecular proton transfer (ESIPT). Interestingly, this compound shows ultra-sensitivity and selectivity in the detection of Al(iii) (12 pM; 456 ppt). The OM was capable of pH sensing and was also tested for internalization in cancerous cells for intracellular imaging. Computational modeling was performed and the results were in good agreement with the experimental UV-Vis spectrum and the energy gap obtained in basic and acidic media...
July 11, 2018: Analyst
Kaixin Xu, Longwei He, Xueling Yang, Yunzhen Yang, Weiying Lin
A H2O2-responsive fluorescent chemosensor (CNBE) with a ratiometric emission signal was elaborately designed and synthesized. The ratio signal of the chemosensor was manipulated by an interplaying ICT-activated FRET mechanism. The ratiometric fluorescence imaging was successfully applied to detect H2O2 using CNBE in living cells and zebrafish.
July 11, 2018: Analyst
S Mukherjee, J Á Martínez-González, D P Dowling, A A Gowen
The static water contact angle (CA) quantifies the degree of wetting that occurs when a surface encounters a liquid, e.g. water. This property is a result of factors such as surface chemistry and local roughness and is an important analytical parameter linked to the suitability of a surface for a given bioanalytical process. Monitoring the spatial variation in wettability over surfaces is increasingly critical to analysts and manufacturers for improved quality control. However, CA acquisition is often time-consuming because it involves measurements over multiple spatial locations, independent sampling and the need for a single instrument operator...
July 10, 2018: Analyst
Giuseppe Pezzotti, Ryan M Bock, Bryan J McEntire, Tetsuya Adachi, Elia Marin, Francesco Boschetto, Wenliang Zhu, Osam Mazda, Sonny B Bal
Over the next two decades, a strong demographic demand for arthroplastic devices coupled with a decreased efficacy of antibiotics has been predicted to result in an exponential increase in the number of periprosthetic joint infections (PJIs). Advanced strategies are therefore required to improve the local peri-implant immune response and curb the pathogenic events of bacterial adhesion and biofilm formation. The use of biomaterials that autonomously counter infections is one approach to improve orthopedic outcomes...
July 10, 2018: Analyst
Boris Brkić, Neil France, Stamatios Giannoukos, Stephen Taylor
We report a novel portable 17 kg system based on a quadrupole mass spectrometer (QMS) with an electronic power consumption of 24 W. The system can be used for the in-field identification of gases and volatile/semivolatile organic compounds (VOCs/SVOCs). The mass analyser is a custom-made quadrupole mass filter with a Brubaker pre-filter that gives a mass range of m/z 1-500. It is an upgrade of the previous m/z 1-200 range triple filter analyser system. Analyser design was optimized using 3D numerical simulations as a performance trade-off between single and triple filter designs while maintaining high sensitivity and ease of integration...
July 10, 2018: Analyst
Jun-Tao Cao, Fu-Rao Liu, Fang Hou, Juan Peng, Shu-Wei Ren, Yan-Ming Liu
The cathodic electrochemiluminescence (ECL) behaviour of nontoxic MoS2 quantum dots (QDs) was studied for the first time using potassium peroxydisulfate as the co-reactant. Ag-PAMAM NCs, serving as difunctional tags for quenching and enhancing ECL of MoS2-reduced graphene oxide composites, were introduced into the ECL detection system for signal amplification. By modulating the interparticle distance between MoS2 QDs and Ag-PAMAM NCs, the ECL quenching from resonance energy transfer and the ECL enhancement from surface plasma resonance were realized...
July 6, 2018: Analyst
Wendong Chen, Lan Chen, Ruijun Tian
Phosphoproteomics has become a popular proteomic technology for exploring cellular signaling networks. However, current approaches often require milligrams of protein samples which hamper their applications for translational studies with limited starting materials. In this study, we aimed to challenge the lowest starting material limit for phosphoproteome profiling. By carefully optimizing the well-established high-pH reversed-phase (RP) fractionation plus Ti4+-IMAC enrichment strategy, we achieved the identification of 15 260 and 8936 unique phosphopeptides from only 500 μg and 250 μg predigested peptides, respectively...
July 6, 2018: Analyst
Marianna Eliášová Sohová, Michal Bodík, Peter Siffalovic, Nikola Bugárová, Martina Labudová, Miriam Zaťovičová, Tibor Hianik, Mária Omastová, Eva Majková, Matej Jergel, Silvia Pastoreková
Graphene oxide (GO), a partially oxidized two-dimensional allotrope of carbon, is an attractive nanocarrier for cancer diagnostics and therapy. The nanometer-sized GO is known to permeate cell membranes. Herein we studied the cellular uptake pathways of GO nanoflakes by cancer and non-cancerous cell lines. By employing confocal Raman imaging, we were able to track the GO cellular uptake in living cells (C33 and MDCK) without any additional fluorescent or plasmonic labels. This specific progress in label-free Raman imaging of GO facilitates the monitoring of nanoflakes at the cellular level...
July 6, 2018: Analyst
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