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ACS Sensors

Huizhen Yuan, Wei Ji, Shuwen Chu, Qiang Liu, Siyu Qian, Jianye Guang, Jiabin Wang, Xiuyou Han, Jean-François Masson, Wei Peng
As a highly toxic heavy metal ion, divalent mercuric ion (Hg2+) is one of the most widely diffused and hazardous environmental pollutants. In this paper, a simple, portable, and inexpensive fiber-optic sensor based on surface plasmon resonance (SPR) effect was developed for Hg2+ detection, which takes advantage of 4-mercaptopyridine (4-MPY) functionalized Au nanoparticles (Au NPs/4-MPY) as a signal amplification tag. Based on the coordination between Hg2+ and nitrogen in the pyridine moiety, we developed the sensor by self-assembling 4-MPY on Au film surfaces to capture Hg2+, and then introducing Au NPs/4-MPY to generate a plasmonic coupling structure with the configuration of nanoparticle-on-mirror...
February 20, 2019: ACS Sensors
Anisa Kaur, Kumar Sapkota, Soma Dhakal
Multiplex detection of biomolecules is important in bionanotechnology and clinical diagnostics. Multiplexing using engineered solutions such as microarrays, synthetic nanopores, and DNA barcodes are promising but they require sophisticated design/engineering and typically yield semi-quantitative information. Single-molecule FRET (smFRET) is an attractive tool in this regard as it enables both sensitive and quantitative detection. However, multiplexing with smFRET remains a great challenge as it requires either multiple excitation sources, an antenna system created by multiple FRET pairs, or multiple acceptors of the donor fluorophore, which not only complicates the labeling schemes but also data analysis due to overlapping of FRET efficiencies (EFRET)...
February 20, 2019: ACS Sensors
Renhui Zhan, Xiaofeng Li, Wenfei Guo, Xiaojun Liu, Zhi-Xian Liu, Kehua Xu, Bo Tang
A growing body of evidence indicates that micropeptides encoded by long noncoding RNAs (lncRNAs) act independently or as regulators of larger proteins in fundamental biological processes, especially in the maintenance of cellular homeostasis. However, due to their small size and low intracellular expression, visual monitoring of micropeptides in living cells is still a challenge. In this work, we have designed and synthesized an aptamer-based near-infrared fluorescence nanoprobe for fluorescence imaging of phospholamban (PLN), which is an intracellular micropeptide that affects calcium homeostasis, and is closely associated with human heart failure in clinic...
February 19, 2019: ACS Sensors
Ali Rahimian, Christian Siltanen, Hamid Feyzizarnagh, Patricio Escalante, Alexander Revzin
Cytokines are produced by leukocytes in blood and may be used as indicators of malignancies or infections. The objective of this study was to develop a strategy for immunosensing cytokines in whole, unprocessed human blood. Microfluidic droplet generation was employed to fabricate ∼400 μm diameter microcapsules with a hydrogel shell and an aqueous core containing sensing microbeads. The hydrogel shell was composed of poly(ethylene glycol) forming a thin (∼10 μm) immunoisolation layer protecting antibody-modified microbeads inside the capsule from immune cells on the outside...
February 18, 2019: ACS Sensors
Amy Elizabeth Valera, Nathan Taylor Nesbitt, Michelle Archibald, Michael J Naughton, Thomas C Chiles
Rapid diagnosis of infectious disease at the site of the patient is critical for preventing the escalation of an outbreak into an epidemic. Devices suited to point-of-care (POC) diagnosis of cholera must not only demonstrate clinical laboratory levels of sensitivity and specificity, but must do so in a portable and low-cost manner, with a simplistic readout. We report work towards an on-chip electrochemical immunosensor for the detection of cholera toxin subunit B (CTX), based on a dendritic gold architecture biofunctionalized via poly-(2-cyano-ethyl)pyrrole (PCEPy)...
February 18, 2019: ACS Sensors
Mickael Mateos, Marie-Donga Tchangaï, Rita Meunier-Prest, Olivier Heintz, Frederic Herbst, Jean-Moïse Suisse, Marcel Bouvet
We present a new device called double lateral heterojunction (DLH) as ammonia sensor in humid atmosphere. It combines polyani-line derivatives in their poor conducting state with a highly conductive molecular material, lutetium bisphthalocyanine, LuPc2. The polyaniline and poly(2,5-dimethoxyaniline) are electrodeposited on ITO interdigitated electrodes, leading to an original device that can be obtained only by electrochemistry and not by other solution processing techniques. Both polymers lead to highly con-ducting materials that require a neutralization step before their covering by LuPc2...
February 18, 2019: ACS Sensors
Erno Lindner, Marcin Guzinski, Taskia Ahammad Khan, Bradford D Pendley
In this paper, we raise questions that researchers have to ask if they intend to replace a conventional reference electrode with an ionic liquid-based reference electrode and try to answer these questions based on our experiences and literature data. Among these questions, the most important is which ionic liquid should be used. However, beyond the chemical composition of the ionic liquid, to realize all the potential benefits of ionic-liquid based reference electrodes, there are additional, equally important considerations...
February 14, 2019: ACS Sensors
Robin Singh, Danhao Ma, Lionel Kimerling, Anuradha Murthy Agarwal, Brian Anthony
We demonstrate the chemical characterization of aerosol particles with on-chip spectroscopy using a photonic cavity enhanced silicon nitride (Si3N4) racetrack resonator-based sensor. The sensor operates over a broad and continuous wavelength range, showing cavity enhanced sensitivity at specific resonant wavelengths. Analysis of the relative change in the quality factor of the cavity resonances successfully yields the absorption spectrum of the aerosol particles deposited on the resonators. Detection of N-methyl aniline-based aerosol detection in the Near InfraRed (NIR) range of 1500 nm to 1600 nm is demonstrated...
February 14, 2019: ACS Sensors
Christian Grundahl Frankær, Martin Rosenberg, Marco Santella, Kishwar J Hussain, Bo W Laursen, Thomas Just Sørensen
Since Sørensen and Bjerrum defined the pH scale, we have relied on two methods for determining pH, the colorimetric or the electrochemical. For pH electrodes, calibration is easy as a linear response is observed in the interesting pH range from 1 to ~12. For colorimetric sensors, the response follows the sigmoidal Bjerrum diagram of an acid-base equilibrium. Thus, calibration of colorimetric sensors is more complex. Here, seven pH responsive fluorescent dyes based on the same diazaoxatriangulenium (DAOTA) fluorophore linked to varying receptor groups were prepared...
February 14, 2019: ACS Sensors
Gizem Ert Uuml Rk Bergdahl, Tilde Andersson, Maria Allhorn, Sofie Yngman, Rainer Timm, Rolf Lood
In this study, a surface plasmon resonance biosensor was developed for the detection and quantification of a secreted bacterial factor (RoxP) from skin. Molecular imprinting method was used for the preparation of sensor chips and five different monomer-cross linker compositions were evaluated for sensitivity, selectivity, affinity and kinetic measurements. The most promising MIP was characterized by using scanning electron microscopy, atomic force microscopy, and cyclic voltammetry. Limit of detection (LOD) value was calculated as 0...
February 13, 2019: ACS Sensors
Olga Casals, Nicolai Markiewicz, Cristian Fabrega, Isabel Gracia, Carles Cané, Hutomo Suryo Wasisto, Andreas Waag, Joan Daniel Prades
A film of gas sensitive ZnO nanoparticles has been coupled with a low-power micro light plate (µLP) to achieve a NO2-parts-per-billion conductimetric gas sensor operating at room temperature. In this µLP configuration, an InGaN-based LED (emitting at 455 nm) is integrated at a few hundred nanometers distance from the sensor material, leading to sensor photoacti-vation with well controlled, uniform and high irradiance condi-tions, and very low electrical power needs. The response curves to different NO2 concentrations as a function of the irradiance displayed a bell-like shape...
February 13, 2019: ACS Sensors
Benjamin Cressiot, Hadjer Ouldali, Manuela Pastoriza-Gallego, Laurent Bacri, F Gisou van der Goot, Juan Pelta
Nanopore electrical approach is a breakthrough in single molecular level detection of particles as small as ions, and complex as biomolecules. This technique can be used for molecule analysis, and characterization as well as for the understanding of confined medium dynamics in chemical or biological reactions. Altogether, the information obtained from these kinds of experiments will allow to address challenges in a variety of biological fields. The sensing, design and manufacture of nanopores is crucial to obtain these objectives...
February 12, 2019: ACS Sensors
Hanbi Kim, Jong Uk Lee, Soohyun Kim, Sojin Song, Sang Jun Sim
Blood-based diagnosis (Hemodiagnosis) of Alzheimer's disease (AD) is emerging as a promising alternative of cerebrospinal fluid-based methods because blood contains various kinds of AD biomarkers, including amyloid beta 1-40, 1-42, and τ (tau) protein. However, with current technology, the accuracy of the blood plasma-based methods is relatively low compared to the traditional methods because the concentration of AD biomarkers in blood plasma is incredibly low and diverse interfer-ence is present in blood plasma, which hinders precise detection...
February 12, 2019: ACS Sensors
Julien Proust, Jérôme Martin, Davy Gerard, Jean-Louis Bijeon, Jerome Plain
Thanks to their small sensing volume, nanosensors based on localized surface plasmon resonances (LSPR) allow the detection of minute amounts of analytes, down to the single molecule limit. However, the detected analytes are often large molecules, such as proteins. The detection of small molecules remains largely unexplored. Here, we use a hybrid photonic-plasmonic nanosensor to detect a small target molecule (pyridine). The sensor's design is based on a dielectric photonic microstructure acting as an antenna, which efficiently funnels light towards a plasmonic transducer and enhance the detection efficiency...
February 8, 2019: ACS Sensors
Sawsen Azzouzi, Zina Fredj, Anthony P F Turner, Mounir Ben Ali, Wing Cheung Mak
Current electrochemical biosensors for multiple miRNAs require tedious immobilization of various nucleic acid probes. Here, we demonstrate an innovative approach using a generic neutravidin biosensor combined with electrochemically encoded responsive nanolabels for facile and simultaneous multiplexed detection of miRNA-21 and miRNA-141. The selectivity of the biosensor arises from the intrinsic properties of the electrochemically encoded responsive nanolabels, comprising biotinylated molecular beacons (biotin-MB) and metal nanoparticles (metal-NPs)...
February 7, 2019: ACS Sensors
Esma Sari, Recep Uzek, Arben Merkoçi
In this study, a novel photoluminescence material for the detection of tributyltin (TBT) was developed by using a paper-based nanocomposite system. For this purpose, molecularly imprinted polymeric nanoparticles (MIN) were synthesized with mini-emulsion polymerization technique. Graphene quantum dots obtained by the hydrothermal pyrolysis were immobilized to the nanoparticle surface via EDC-NHS coupling. The fabrication of sensing platform for TBT can be divided into two steps that are the preparation of nanocomposite and the applying the nanocomposite onto nitrocellulose membrane...
February 6, 2019: ACS Sensors
Nur P Damayanti, Kevin Buno, Sherry L Voytik Harbin, Joseph M K Irudayaraj
Acetyltransferase is a member of the transferase group responsible for transferring an acetyl group from acetyl-CoA to amino group of a histone lysine residue. Past efforts on histone acetylation monitoring involved biochemical analysis that do not provide spatiotemporal information in a dynamic format. We propose a novel approach to monitor acetyltransferase acetylation in live single cells using time correlated single photon counting fluorescence lifetime imaging (TCSPC-FLIM) with peptide biosensors. Utilizing 2D and 3D cultures we show that the peptide sensor has a specific response to acetyltransferase enzyme activity in a fluorescence lifetime dependent manner ( P < 0...
February 6, 2019: ACS Sensors
Jungil Choi, Amay J Bandodkar, Jonathan T Reeder, Tyler R Ray, Amelia Turnquist, Sung Bong Kim, Nathaniel Nyberg, Aurélie Hourlier-Fargette, Jeffrey B Model, Alexander J Aranyosi, Shuai Xu, Roozbeh Ghaffari, John A Rogers
Real-time measurements of the total loss of sweat, the rate of sweating, the temperature of sweat, and the concentrations of electrolytes and metabolites in sweat can provide important insights into human physiology. Conventional methods use manual collection processes (e.g., absorbent pads) to determine sweat loss and lab-based instrumentation to analyze its chemical composition. Although such schemes can yield accurate data, they cannot be used outside of laboratories or clinics. Recently reported wearable electrochemical devices for sweat sensing bypass these limitations, but they typically involve on-board electronics, electrodes, and/or batteries for measurement, signal processing, and wireless transmission, without direct means for measuring sweat loss or capturing and storing small volumes of sweat...
February 1, 2019: ACS Sensors
Yoshiki Soda, Daniel Citterio, Eric Bakker
A distance-based analysis of potassium ion (K+) is introduced that is performed on a microfluidic paper-based analyti-cal device (µPAD) coupled to an ion-selective capillary sensor. The concept is based on two sequential steps, the selec-tive replacement of analyte ion with an ionic dye, and the detection of this dye in a distance-based readout on paper. To achieve the first step, the capillary sensor holds a poly (vinyl chloride) (PVC) membrane film layer plasticized by dioctyl sebacate (DOS) that contains the potassium ionophore valinomycin, a lipophilic cation-exchanger and the ion-ic indicator Thioflavin T (ThT) on its inner wall...
January 31, 2019: ACS Sensors
Mengdi Lu, Hu Zhu, C Geraldine Bazuin, Wei Peng, Jean-François Masson
Dense arrays of well-dispersed gold nanoparticles (AuNPs) on optical fibers are shown to bridge the gap in sensitivity and sensing performance between localized surface plasmon resonance (LSPR) and classical SPR sensing. A simple self-assembly method relying on a poly(styrene-b-4-vinylpyridine) (PS-b-P4VP) block copolymer brush layer was used to immobilize AuNPs of different diameters from 10 to 92 nm on optical fibers. In comparison with standard AuNP deposition methods using (3-aminopropyl)trimethoxysilane (APTMS) and polyelectrolytes, the sensitivity with the PS-b-P4VP templating method was found to be 3-fold better, a consequence of the smaller gap between particles and the presence of fewer AuNP aggregates...
January 30, 2019: ACS Sensors
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