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Sensors and Actuators. B, Chemical

Grzegorz Pasternak, John Greenman, Ioannis Ieropoulos
Standard Biological Oxygen Demand (BOD) analysis requires 5 days to complete. To date, microbial fuel cell biosensors used as an alternative method for BOD assessment requires external apparatus, which limits their use for on-line monitoring in remote, off-grid locations. In this study, a self-powered, floating biosensor was developed for online water quality monitoring. This approach eliminated the need for external apparatus and maintenance that would otherwise be required by other techniques. The biosensor was able to detect urine in freshwater and turn ON a visual and sound cues (85 dB)...
June 2017: Sensors and Actuators. B, Chemical
Michael M Baksh, M G Finn
Backscattering interferometry (BSI) was used to determine the association constants for four well-known biomolecular interactions: protein A + IgG, trypsin + antitrypsin, trypsin + p-aminobenzamidine, and antithrombin + heparin. Each gave well-defined binding curves and Kd values in close agreement with published findings obtained using other techniques. These results stand in direct contrast to the claims in a 2015 publication in this journal (Discussion of "Back Scattering Interferometry revisited-a theoretical and experimental investigation" Jørgensen, T...
May 2017: Sensors and Actuators. B, Chemical
Hao Wan, Heyu Yin, Andrew J Mason
Intense study on gas sensors has been conducted to implement fast gas sensing with high sensitivity, reliability and long lifetime. This paper presents a rapid amperometric method for gas sensing based on a room temperature ionic liquid electrochemical gas sensor. To implement a miniaturized sensor with a fast response time, a three electrode system with gold interdigitated electrodes was fabricated by photolithography on a porous polytetrafluoroethylene substrate that greatly enhances gas diffusion. Furthermore, based on the reversible reaction of oxygen, a new transient double potential amperometry (DPA) was explored for electrochemical analysis to decrease the measurement time and reverse reaction by-products that could cause current drift...
April 2017: Sensors and Actuators. B, Chemical
Sisi Chen, Qingbo Yang, Hai Xiao, Honglan Shi, Yinfa Ma
Biological studies of tissues and cells have enabled numerous discoveries, but these studies still bear potential risks of invalidation because of cell heterogeneity. Through high-accuracy techniques, recent studies have demonstrated that discrepancies do exist between the results from low-number-cell studies and cell-population-based results. Thus the urgent need to re-evaluate key principles on limited number of cells has been provoked. In this study, a novel designed dual-core fiber-optic pH micro-probe was fabricated and demonstrated for niche environment pH sensing with high spatial resolution...
March 31, 2017: Sensors and Actuators. B, Chemical
Champak Das, Guochun Wang, Qian Sun, Bradley Ledden
We report here, the design and development of an automated near real-time continuous detection system for lactate, glutamate, pyruvate and glucose using microdialysis probe. The system developed can automatically push perfusate through microdialysis probe (20, 100 and 1000 kDa MWCO cutoff probe) at low to medium flow rate of 0.5-2 μL/min with almost 100% fluid recovery. The microdialysate collected from the probe is analyzed automatically for these four metabolite biomarkers. It operates in a continuous mode with measurements of all four biomarkers once every 20 min...
January 2017: 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
Bin Liu, Xiaoman Bi, Lucas McDonald, Yi Pang, Danqing Liu, Chengjun Pan, Lei Wang
Human serum albumin (HSA) as the most abundant protein in human blood plasma, serves many physiological functions. The dysregulation of HSA in serum or in urine is associated with various diseases, such as cirrhosis of liver, multiple myeloma, and cardiovascular disease. Therefore, to quantify HSA in body fluids with high selectivity and sensitivity is of great significance for disease diagnosis and preventive medicine. We herein developed a series of amide-functionalized flavonoids probes, 1-3, for recognition of human serum albumin...
November 29, 2016: Sensors and Actuators. B, Chemical
Yichen Duan, Laurent Pirolli, Andrew V Teplyakov
The poisoning of H2S sensing material based on the mixture of acid-treated carbon nanotubes, CuO and SnO2 was investigated by exposing the material to high doses of H2S (1% in volume) and following the changes spectroscopically. The presence of metal sulfides (CuS and SnS2), sulfates and thiols was confirmed on the surface of this material as the result of H2S poisoning. Further study revealed that leaving this material in air for extended period of time led to reoxidation of metal sulfides back to metal oxides...
November 1, 2016: Sensors and Actuators. B, Chemical
Jianguo Ma, Yuan Luo, René R Sevag Packard, Teng Ma, Yichen Ding, Parinaz Abiri, Yu-Chong Tai, Qifa Zhou, Kirk K Shung, Rongsong Li, Tzung Hsiai
Plaque rupture causes acute coronary syndromes and stroke. Intraplaque oxidized low density lipoprotein (oxLDL) is metabolically unstable and prone to induce rupture. We designed an intravascular ultrasound (IVUS)-guided electrochemical impedance spectroscopy (EIS) sensor to enhance the detection reproducibility of oxLDL-laden plaques. The flexible 2-point micro-electrode array for EIS was affixed to an inflatable balloon anchored onto a co-axial double layer catheter (outer diameter = 2 mm). The mechanically scanning-driven IVUS transducer (45 MHz) was deployed through the inner catheter (diameter = 1...
November 1, 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
Nalin Katta, Douglas C Meier, Kurt D Benkstein, Steve Semancik, Baranidharan Raman
A number of sensing technologies, using a variety of transduction principles, have been proposed for non-invasive chemical sensing. A fundamental problem common to all these sensing technologies is determining what features of the transducer's signal constitute a chemical fingerprint that allows for precise analyte recognition. Of particular importance is the need to extract features that are robust with respect to the sensor's age or stimulus intensity. Here, using pulsed stimulus delivery, we show that a sensor's operation can be modeled as a linear input-output (I/O) transform...
September 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
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