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Sensors and Actuators. B, Chemical

Junyi Shang, Jing Yan, Zhixing Zhang, Xian Huang, Panita Maturavongsadit, Bing Song, Yuan Jia, Tieying Ma, Dachao Li, Kexin Xu, Qian Wang, Qiao Lin
We present a hydrogel-based affinity microsensor for continuous glucose measurements. The microsensor is based on microelectromechanical systems (MEMS) technology, and incorporates a synthetic hydrogel that is attached to the device surface via in situ polymerization. Glucose molecules that diffuses into and out of the device binds reversibly with boronic acid groups in the hydrogel via affinity binding, and causes changes in the dielectric properties of the hydrogel, which can be measured using a MEMS capacitive transducer to determine the glucose concentration...
December 2016: Sensors and Actuators. B, Chemical
Alexander C Sun, Chengyang Yao, A G Venkatesh, Drew A Hall
Cellular phone penetration has grown continually over the past two decades with the number of connected devices rapidly approaching the total world population. Leveraging the worldwide ubiquity and connectivity of these devices, we developed a mobile phone-based electrochemical biosensor platform for point-of-care (POC) diagnostics and wellness tracking. The platform consists of an inexpensive electronic module (< $20) containing a low-power potentiostat that interfaces with and efficiently harvests power from a wide variety of phones through the audio jack...
November 1, 2016: Sensors and Actuators. B, Chemical
Michael S Wiederoder, Isaac Misri, Don L DeVoe
A sensitive and rapid impedemetric immunosensor is demonstrated utilizing porous volumetric microfluidic detection elements and silver enhanced gold nanoparticle probes. The porous detection elements significantly increase capture probe density and decrease diffusion length scales compared to conventional planar sensors to improve target capture efficiency and enhance impedance signal. In this work, a packed bed of silica beads functionalized with antibody probes serves as a porous sensor element within a thermoplastic microchannel, with an interdigitated gold electrode microarray used to measure impedance changes caused by the concentration dependent formation of silver aggregates...
October 29, 2016: Sensors and Actuators. B, Chemical
Ying Zhou, Srinjan Basu, Kai J Wohlfahrt, Steven F Lee, David Klenerman, Ernest D Laue, Ashwin A Seshia
A multi-layer device, combining hydrodynamic trapping with microfluidic valving techniques, has been developed for on-chip manipulation and imaging of single cells and particles. Such a device contains a flow layer with trapping channels to capture single particles or cells and a control layer with valve channels to selectively control the trap and release processes. Particles and cells have been successfully trapped and released using the proposed device. The device enables the trapping of single particles with a trapping efficiency of greater than 95%, and allows for single particles and cells to be trapped, released and manipulated by simply controlling corresponding valves...
September 2016: Sensors and Actuators. B, Chemical
Jessica T Wen, Karen Bohorquez, Hideaki Tsutsui
We report a new polydiacetylene (PDA) sensor strip for simple visual detection of zinc ions in aqueous solution. The specificity of this sensor comes from Zn(2+) DNA aptamer probes conjugated onto PDA. Effects of aptamer length and structure on the sensitivity of PDA's color transition were first investigated. PDA conjugated with the optimal aptamer sequence was then coated onto a strip of polyvinylidene fluoride membrane and photopolymerized by UV exposure. The newly developed sensor successfully exhibited a blue-to-red chromatic change in a semi-quantitative manner in response to zinc ions...
September 2016: Sensors and Actuators. B, Chemical
Lee A Greenawald, Gerry R Boss, Aaron Reeder, Suzanne Bell
An inexpensive paper-based sensor was developed for detecting low ppm concentrations of hydrogen sulfide gas. A piece of filter paper containing aquohydroxocobinamide [OH(H2O)Cbi] was placed on the end of a bifurcated optical fiber, and the reflectance spectrum of the OH(H2O)Cbi was monitored during exposure to 10.0 ppm hydrogen sulfide gas (NIOSH recommended exposure limit). Reaction of sulfide (HS-) yielded an increase in reflectance from 400-450 nm, and decrease from 470-550 nm. Spectral changes were monitored as a function of time at 25, 50, and 85% relative humidity...
July 2016: Sensors and Actuators. B, Chemical
Haipeng Yang, Taibur Rahman, Dan Du, Rahul Panat, Yuehe Lin
Printed Electronics has emerged as an important fabrication technique that overcomes several shortcomings of conventional lithography and provides custom rapid prototyping for various sensor applications. In this work, silver microelectrode arrays (MEA) with three different electrode spacing were fabricated using 3-D printing by the aerosol jet technology. The microelectrodes were printed at a length scale of about 15 μm, with the space between the electrodes accurately controlled to about 2 times (30 μm, MEA30), 6...
July 2016: Sensors and Actuators. B, Chemical
Shih-Chuan Liao, Jing Peng, Michael G Mauk, Sita Awasthi, Jinzhao Song, Harvey Friedman, Haim H Bau, Changchun Liu
Nucleic acid amplification-based diagnostics offer rapid, sensitive, and specific means for detecting and monitoring the progression of infectious diseases. However, this method typically requires extensive sample preparation, expensive instruments, and trained personnel. All of which hinder its use in resource-limited settings, where many infectious diseases are endemic. Here, we report on a simple, inexpensive, minimally-instrumented, smart cup platform for rapid, quantitative molecular diagnostics of pathogens at the point of care...
June 28, 2016: Sensors and Actuators. B, Chemical
Gema M Duran, Tomás E Benavidez, Jason G Giuliani, Angel Rios, Carlos D Garcia
A one-step approach for the synthesis and integration of copper nanoparticles (CuNPs) onto paper-based carbon electrodes is herein reported. The method is based on the pyrolysis (1000 °C under a mixture of 95% Ar / 5% H2 for 1 hour) of paper strips modified with a saturated solution of CuSO4 and yields to the formation of abundant CuNPs on the surface of carbonized cellulose fibers. The resulting substrates were characterized by a combination of scanning electron microscopy, EDX, Raman spectroscopy as well as electrical and electrochemical techniques...
May 2016: Sensors and Actuators. B, Chemical
Sam Emaminejad, Kee-Hyun Paik, Vincent Tabard-Cossa, Mehdi Javanmard
In this manuscript, we present three different micro-impedance sensing architectures for electronic counting of cells and beads. The first method of sensing is based on using an open circuit sensing electrode integrated in a micro-pore, which measures the shift in potential as a micron-sized particle passes through. Our micro-pore, based on a funnel shaped microchannel, was fabricated in PDMS and was bound covalently to a glass substrate patterned with a gold open circuit electrode. The amplification circuitry was integrated onto a battery-powered custom printed circuit board...
March 1, 2016: Sensors and Actuators. B, Chemical
Samuel S R Dasary, Yolanda K Zones, Sandra L Barnes, P C Ray, Anant K Singh
Alizarin functionalized on plasmonic gold nanoparticle displays strong surface enhanced Raman scattering from the various Raman modes of Alizarin, which can be exploited in multiple ways for heavy metal sensing purposes. The present article reports a surface enhanced Raman spectroscopy (SERS) probe for trace level Cadmium in water samples. Alizarin, a highly Raman active dye was functionalized on plasmonic gold surface as a Raman reporter, and then 3-mercaptopropionic acid, 2,6-Pyridinedicarboxylic acid at pH 8...
March 1, 2016: Sensors and Actuators. B, Chemical
Rongsheng Chen, Federico Formenti, Hanne McPeak, Andrew N Obeid, Clive Hahn, Andrew Farmery
Very fast sensors that are able to track rapid changes in oxygen partial pressure (PO2) in the gas and liquid phases are increasingly required in scientific research - particularly in the life sciences. Recent interest in monitoring very fast changes in the PO2 of arterial blood in some respiratory failure conditions is one such example. Previous attempts to design fast intravascular electrochemical oxygen sensors for use in physiology and medicine have failed to meet the criteria that are now required in modern investigations...
January 2016: Sensors and Actuators. B, Chemical
Roya Sheybani, Ellis Meng
Recombination of electrolysis gases (oxidation of hydrogen and reduction of oxygen) is an important factor in operation efficiency of devices employing electrolysis such as actuators and also unitized regenerative fuel cells. Several methods of improving recombination speed and repeatability were developed for application to electrolysis microactuators with Nafion®-coated catalytic electrodes. Decreasing the electrolysis chamber volume increased the speed, consistency, and repeatability of the gas recombination rate...
December 31, 2015: Sensors and Actuators. B, Chemical
Lee A Greenawald, Jay L Snyder, Nicole L Fry, Michael J Sailor, Gerry R Boss, Harry O Finklea, Suzanne Bell
We describe an inexpensive paper-based sensor for rapid detection of low concentrations (ppm) of hydrogen cyanide gas. A piece of filter paper pre-spotted with a dilute monocyanocobinamide [CN(H2O)Cbi] solution was placed on the end of a bifurcated optical fiber and the reflectance spectrum of the CN(H2O)Cbi was monitored during exposure to 1.0-10.0 ppm hydrogen cyanide gas. Formation of dicyanocobinamide yielded a peak at 583 nm with a simultaneous decrease in reflectance from 450-500 nm. Spectral changes were monitored as a function of time at several relative humidity values: 25, 50, and 85% relative humidity...
December 31, 2015: Sensors and Actuators. B, Chemical
Shenglong Yu, Shuxin Wang, Haizhu Yu, Yan Feng, Shuting Zhang, Manzhou Zhu, Hang Yin, Xiangming Meng
A ratiometric two-photon fluorescent probe TNQ was developed based on quinoline platform to detect hydrazine (N2H4) with high selectivity. TNQ exhibited large two-photon absorption cross sections at 710 nm (250 GM) and excellent ratiometric two-photon fluorescent detection signal for hydrazine. TNQ was also successfully applied to selectively detect hydrazine vapor even at a concentration down to 0.05%. Cell cytotoxicity and bio-imaging studies revealed that probe TNQ was cell-permeable and could be used to detect hydrazine in living cells with low cytotoxicity under two-photon excitation...
December 1, 2015: Sensors and Actuators. B, Chemical
Zongyu Geng, Feng Yang, Xi Chen, Nianqiang Wu
It remains a challenge to accurately calibrate a sensor subject to environmental drift. The calibration task for such a sensor is to quantify the relationship between the sensor's response and its exposure condition, which is specified by not only the analyte concentration but also the environmental factors such as temperature and humidity. This work developed a Gaussian Process (GP)-based procedure for the efficient calibration of sensors in drifting environments. Adopted as the calibration model, GP is not only able to capture the possibly nonlinear relationship between the sensor responses and the various exposure-condition factors, but also able to provide valid statistical inference for uncertainty quantification of the target estimates (e...
September 2015: Sensors and Actuators. B, Chemical
James T Fletcher, Brent S Bruck
A dicarboxylated ethynylarene was shown to behave as a fluorescent chemosensor for millimolar concentrations of polyamines when mixed with Cd(II), Pb(II) or Zn(II) ions at micromolar concentrations. A bathochromic shift and intensification of fluorescence emission was observed with increasing amounts of metal ion in the presence of aqueous polyamines buffered at pH = 7.6. Such perturbations manifested as 'turn-on' signals from a ratiometric comparison of emission intensities at 390 nm versus 340 nm. Using Pb(II) as the metal mediator, spermine was selectively detected as a 40-fold signal enhancement relative to spermidine, putrescine, cadaverine and several other non-biogenic diamines...
February 1, 2015: Sensors and Actuators. B, Chemical
Qingbo Yang, Hanzheng Wang, Xinwei Lan, Baokai Cheng, Sisi Chen, Honglan Shi, Hai Xiao, Yinfa Ma
pH sensing at the single-cell level without negatively affecting living cells is very important but still a remaining issue in the biomedical studies. A 70 μm reflection-mode fiber-optic micro-pH sensor was designed and fabricated by dip-coating thin layer of organically modified aerogel onto a tapered spherical probe head. A pH sensitive fluorescent dye 2', 7'-Bis (2-carbonylethyl)-5(6)-carboxyfluorescein (BCECF) was employed and covalently bonded within the aerogel networks. By tuning the alkoxide mixing ratio and adjusting hexamethyldisilazane (HMDS) priming procedure, the sensor can be optimized to have high stability and pH sensing ability...
February 1, 2015: Sensors and Actuators. B, Chemical
KhanhVan T Nguyen, Jeffrey N Anker
Alginate gels are widely used for drug delivery and implanted devices. The rate at which these gels break down is important for controlling drug release. Since the de-gelation may be different in vivo, monitoring this process in situ is essential. However, it is challenging to monitor the gel through tissue due to optical scattering and tissue autofluorescence. Herein we describe a method to detect through tissue the chemically-induced changes in viscosity and de-gelation process of alginate gels using magnetically modulated optical nanoprobes (MagMOONs)...
December 15, 2014: Sensors and Actuators. B, Chemical
Eduardo A Lima, Rachel M Snider, Ronald S Reiserer, Jennifer R McKenzie, Danielle W Kimmel, Sven E Eklund, John P Wikswo, David E Cliffel
Multianalyte microphysiometry is a powerful technique for studying cellular metabolic flux in real time. Monitoring several analytes concurrently in a number of individual chambers, however, requires specific instrumentation that is not available commercially in a single, compact, benchtop form at an affordable cost. We developed a multipotentiostat system capable of performing simultaneous amperometric and potentiometric measurements in up to eight individual chambers. The modular design and custom LabVIEW™ control software provide flexibility and allow for expansion and modification to suit different experimental conditions...
December 1, 2014: Sensors and Actuators. B, Chemical
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