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Using glucose concentration as an inflammation responsive element, we newly established an enzymeless glucose sensor integrated with a chronically implantable peripheral nerve cuff electrode for continuous and in-situ monitoring of local inflammation. The glucose sensor integrated with a nerve cuff electrode was fabricated on a polyimide substrate side-by-side, then the glucose sensor and nerve cuff electrode were reversely folded, and were located inside and outside, respectively. The experimental results reveal that the electroplated black Pt working electrode of the glucose sensor shows an enhancive surface roughness factor of 16.41 and had a good distribution on the flexible polyimide surface, which exhibits distinctly enhanced electro-catalytic activity compared to that obtained with plain Pt. Amperometry and electrochemical impedance spectroscopy indicated that the fabricated sensor had a sensitivity of 7.17 μA/mM cm 2 , an outstanding detection limit of 10 μM, significant selectivity, and excellent recovery performance for enzymeless glucose detection. In order to evaluate the feasibility for inflammation monitoring in the immediate vicinity of the implantable peripheral nerve cuff electrode, the association of an evoked nerve signal recording and glucose concentration was investigated through ex-vivo test using the sciatic nerve of a SD rat.

The development of low or room temperature gas sensors having a response towards a particular target gas becomes a fascinating research topic for low power consumption applications. In this paper, a sensitive room-temperature hydrogen sulfide (H2S) gas sensors based on hydrothermally synthesized undoped zinc oxide (ZnO) and Cu-doped ZnO (CZO) nanostructures decorated with reduced graphene oxide (RGO) are successfully demonstrated. A simple air-spray deposition is employed as an effective method for uniform GO decoration on CZO nanostructured film which is further chemically reduced to form RGO. The influence of Cu-doping on crystallinity, surface-morphological, and chemical compositional properties of the material have been systematically investigated. The gas sensing properties of the synthesized nanocomposite sensors have been studied towards H2S at room temperatures (∼24 °C). Compared with undoped ZnO/RGO, 3CZO/RGO nanocomposite sensor exhibited a better response towards H2S. The sensor response increases almost linearly with the increase in H2S gas concentration and exhibits the evident response of 0.87%–100 ppm H2S at 24 °C with the response and recovery time of 14 and 32 s, and a theoretical limit of detection of about 136 ppb. The enhancement was accredited to the collegial effect of both Cu dopant and RGO. The sensor also shows good selective behavior towards H2S against H2. The H2S sensing mechanism associated with the p-type behavior of the 3CZO/RGO sensor is also discussed at length.

This paper demonstrates a polyimide nerve cuff electrode with a controllable drug loading/release function for stable recording of peripheral nerve signals and stimulation and minimizing inflammation. For control of anti-inflammatory drug loading/release, dexamethasone (DEX)-loaded poly L -lactic acid (PLLA) and/or poly lactic-co-glycol acid (PLGA) nanofibers were deposited on a functional nerve cuff electrode by the electro-spinning method, which can control the weight of DEX loading on the functional nerve cuff electrode. Then, UV patternable polyethylene glycol (PEG) was coated on the functional nerve cuff with DEX-loaded nanofibers for the acceleration of the release rate of the drug. Through high performance liquid chromatography (HPLC), DEX release rates were increased from 16 to 28% (PLLA-loaded nanofibers) and from 68 to 87% (PLGA-loaded nanofibers) due to the increased diffusion rate of DEX after 28 days, respectively. In addition, the functional nerve cuff electrode was electro-polymerized with poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) as a conductive polymer in order to recover the decreased electrical properties caused by PEG patterning. The impedance measured at 1 kHz was 342 Ω mm2, which was extremely lower than the value of 1046 Ω mm2 of PEG-patterned cuff electrodes. Through the acute ex-vivo test of SD rat's sciatic nerve, the functional nerve cuff electrode with PEDOT:PSS exhibited stable and effective recording of the nerve's signals despite PEG patterning.

This paper presents the design and implementation of a pneumatic tactile display with a Flexible Printed Circuit Board (FPCB) based capacitive position sensor integrated for precise position control. The proposed tactile display was designed to stimulate human finger in tangential direction. The size of the fabricated display was 18 mm × 18 mm × 20 mm. The position control range was 2.5 mm for each x and y axis. The resolution of position control was estimated from three repeated experiments as 0.12 mm with feedback control. The hysteresis behavior of the proposed display observed before feedback control has been eliminated.

This paper presents the design, fabrication, and experimental demonstration of an artificial hair sensor made of polymer materials. Long polymer hair structures embedded with flexible three-dimensional piezoresistive sensors were formed on a flexible substrate in two-dimensional arrays to detect an applied external force. The flexible piezoresistor was implemented using a carbon nanotube-polydimethylsiloxane (CNT-PDMS) composite prepared by the mixing of multi-wall carbon nanotubes with PDMS. A CNT-PDMS composite with high conductivity and a high gauge factor was obtained by increasing the CNT concentration in PDMS. In this study, we used a 13% CNT-PDMS composite for fabricating the sensing element that was embedded in the proposed hair sensor. The hair sensor is 4 mm in height and 700 μm in diameter. The implemented device shows a linear and sensitive response in the on-axis mode with a sensitivity of 2900 ppm/μm.

This paper discusses a flexible energy harvester that consists of a polyvinylidene fluoride film attached to a curved substrate in a shell shape for harvesting energy from human motion. The proposed harvester effectively converts mechanical energy into electrical energy during the fast state transition of the shell structure. The results of an experiment demonstrated that shell structures with various curvatures produce high output potential and consequently offer high output power in comparison to a simple flat structure. The single shell structure generates an output power of 0.87 mW at a folding angle of 80° and a folding and unfolding frequency of 3.3 Hz. In addition, fabric with embedded piezoelectric shell structures was designed as an energy harvester in a wearable platform. The fabric, worn on the elbow joints and fingers, generates a high output power of 0.21 mW in spite of slow and irregular motion.

In this paper, we propose and demonstrate a transparent and flexible capacitive tactile sensor which is designed for multi-touch screen application with force sensing. A sensor module is composed of 2D array tactile cells with a spatial resolution of 2 mm to measure the touch force at multiple positions. The device is fabricated by using transparent materials on a transparent plastic substrate. The optical transmittance of the fabricated tactile sensor is approximately 86% in the visible wavelength region, and the maximum bending radius is approximately 30 mm. The cell size is 1 mm × 1 mm, and the initial capacitance of each cell is approximately 900 fF. The tactile response of a cell is measured with a commercial force gauge having a resolution of 1 mN. The sensitivity of a cell is 4%/mN within the full scale range of 0.3 N.

This paper presents the design, fabrication, and characterization of a microfluidic biochip with integrated actuation electrodes used to manipulate a cell and a microbead by dielectrophoresis and sensing electrodes to detect the trapping by using the impedance detection method. Combining deflective dielectrophoretic barriers with controlled pressure-driven liquid flows allows the accurate control of a cell/microbead in suspensions. The threshold voltage for microbead trapping was experimentally verified at various flow rates. The impedance change caused by the blockage of the electrical conducting path between sensing electrodes with the trapping of an MCF7 cell and a polystyrene microbead was measured. The impedance before the trapping of an MCF7 cell was 10.9 MΩ at 1 kHz and increased to 12 MΩ when the cell was placed between sensing electrodes.

This paper reports on a multifunctional microwell plate developed for lab-on-a-chip applications, such as high-throughput cell assay, drug screening, and microbead-based analyses. The proposed device was designed to provide three consecutive functions: the autonomous capture of biomaterials into multiple microwells in a two-dimensional array; active physical sealing of the microwells for isolation; and specific chemical injection into each microwell. The device was implemented with microfabrication technology using polydimethylsiloxane (PDMS) structures on a silicon or glass substrate. The multiple functions of the microwell plate were successfully demonstrated in an experiment using microbeads. The parallel positioning of live cells (CHO DG44) in multiple microwell arrays was achieved, as well as the independent injection of foreign solution into a specific target cell. Also the proposed microwell plate was utilized to capture microbeads, for antibody injection into each microwell, for quantum dot (QD) injection, and for fluorescence detection for a feasible demonstration of a microbead-based assay.

The oscillating behaviour of TGS813 and TGS203S sensors in hazardous gases such as LPG and CO was studied under the oscillating conditions of rectangular wave, applied voltage 5 V, and duty ratio as 30 s/(3 0s+2 0 s). It was shownthat the oscillating behaviour was obviously different with the two type sensors. The data features were extracted by using Fourier and wavelet transform (WT). There were some very obscure differences among the amplitudes in fast Fourier transform (FFT) under different concentrations of LPG or CO. Further FFT analysis showed that it was difficult to discriminate between 800 ppm LPG and 800 ppm CO because of very little difference in the frequency content. By comparison, the corresponding coefficient plots in continuous wavelet transform (CWT) were investigated, and the original signal was also decomposed into coarse approximation A1 and five detailed information D5–D1. The results showed that the WT was more appropriate than FFT for the frequency–time problem.

Square Wave Anodic Stripping Voltammetry (SWASV) was combined with microfabricated microelectrodes to analyze metal ions in aqueous solution and showed excellent performance such as short analysis time about 1 min per experiment, simultaneous detection of several ions and very low detection limit as low as several nanomoles per liter (i.e. sub-ppb in mass) without any of supporting electrolyte and stirring during analysis. Nafion, a famous ion-exchanging polymer, was introduced to protect the electrode surface from obstructing materials. The Nafion-coated microelectrode was free from disturbing impurities and was capable of analyzing natural water samples directly. Results from the direct water analysis showed similar performance to those from pre-treated samples in both sensitivity and analysis time. To secure the reproducibility of Nafion-coated electrode, a simple electrochemical cleaning method with potential sweep was used and the electrode remained reliable to continued experiments. Nafion-coated microelectrodes were further examined via the comparison with ICP–MS data.

In this paper, we report a miniaturized low-power wireless remote environmental monitoring system. This system has been developed for on-site monitoring of water pollution by heavy-metal ions. The system is composed of three parts: an electrochemical sensor module using microfabricated electrodes for detecting heavy-metal contamination in sample water; a custom potentiostat module including readout circuitry, analog-to-digital converter and microcontroller; and a radio frequency (RF) module for sending detected signals to a base station through wireless communication. The electrochemical sensor module is implemented using microfabricated mercury working electrodes (WEs), solid-state reference electrode (SSRE), and platinum counter electrode (CE). For the low-power operation, direct frequency-shift keying (FSK) modulation and simple binary FSK demodulation methods are used for RF module which is realized using 0.18 μm CMOS technology. All the modules are hybrid integrated in a printed circuit board (PCB) and low-power consumption below 1 mW has been achieved.