A field effect transistor (FET)-based immunosensor was developed for diabetes monitoring by detecting the concentrations of glycated hemoglobin (HbA1c) and hemoglobin (Hb). This immunosensor consists of a FET-based sensor chip and a disposable extended-gate electrode chip. The sensor chip was fabricated by standard CMOS process and was integrated with signal readout circuit. The disposable electrode chip, fabricated on polyester plastic board by Micro-Electro-Mechanical-Systems (MEMS) technique, was integrated with electrodes array and micro reaction pool. Biomolecules were immobilized on the electrode based on self-assembled monolayer and gold nanoparticles. Experimental results showed that the immunosensor achieved a linear response to HbA1c with the concentration from 4 to 24 μg/ml, and a linear response to Hb with the concentration from 60 to 180 μg/ml.

Heavy metal ion pollution problems have had a terrible influence on human health and the environment. Therefore, the monitoring of heavy metal ions is of great practical significance. In this paper, an electrochemical three-electrode system was fabricated and integrated on nitrocellulose membrane (NC) by the use of magnetron sputtering technology, which exhibited a uniform arrangement of porous structure without further film modification. This paper-based sensor chip was used for Cu2+ detection by square-wave stripping voltammetry (SWSV). Within the ranges of 5–200 μg·L−1 and 200–1000 μg·L−1, it showed good linearity of 99.58% and 98.87%, respectively. The limit of detection was 2 μg·L−1. On the basis of satisfying the detection requirements (10 μg·L−1), the integrated sensor was small in size and inexpensive in cost. Zn2+, Cd2+, Pb2+ and Bi3+ were also detected by this paper-based sensor chip with good linearity.

This work describes the fabrication, characterization, and application of a gold microband array electrode (MAE) for the determination of phosphate in fresh water samples. The working principle of this MAE is based on the reduction of a molybdophosphate complex using the linear sweep voltammetric (LSV) method. The calibration of this microsensor was performed with standard phosphate solutions prepared with KH2PO4 and pH adjusted to 1.0. The microsensor consists of a platinum counter electrode, a gold MAE as working electrode, and an Ag/AgCl electrode as reference electrode. The microelectrode chips were fabricated by the Micro Electro-Mechanical System (MEMS) technique. To improve the sensitivity, gold nanoparticles (AuNPs) were electrodeposited on the working electrode. With a linear range from 0.02 to 0.50 mg P/L, the sensitivity of the unmodified microsensor is 2.40 μA per (mg P/L) (R2 = 0.99) and that of the AuNPs-modified microsensor is 7.66 μA per (mg P/L) (R2 = 0.99). The experimental results showed that AuNPs-modified microelectrode had better sensitivity and a larger current response than the unmodified microelectrode.