Environmental Bio-chemical Sensor


Miniaturized biochemical analysis system can be applied to autonomous instrument for environmental field measurement, automatic chemical analyzer and biomedical field such as blood analysis, micro dosing system, DNA analysis and etc. This system is composed of three parts, that is, micro-fluidic components that pick and handle samples, sensor/detector components which analysis the samples and signal processor/controller components that are charge of electrical control and signal processing of the other two parts.

Micro-fluidic Components

It is required that control very little liquid, because the system uses very small quantity of samples. Required operations for the systems are extraction of sample, proper filtration and sample mixing for pretreatments and etc, and for these processes some structures (such as micropump, microvalve, mixer, micro-channel and micro needle) must be constructed. For low voltage operation of micropump and microvalve, the actuator using electromagnetic force can be applied. The electroplating of copper and NiFe permalloy, bulk micromachining and wafer bonding techniques are used for the fabrication

Sensor/detector components

To obtain some information, the biochemical signals by sample reactions must be converted to electrical signals. For the electrochemical sensor, some electrodes and adequate ion-exchange membrane or polymer membrane are required. Next figures show the mercury electrode for the detection of heavy-metal-ions and the result of analysis. Popular method for DNA-sequencing is capillary electrophoresis and optical detection and for this analysis, micro-channels and optical detectors are needed.

Signal processor/controller

Low noise amplifiers to deal with small output signal of sensor, micro-controllers for signal generation or process and D/A, A/D converters are the basic electrical units for the miniaturized biochemical analysis systems.


Related Publication
  1. "Analysis of heavy-metal-ions using mercury microelectrodes and a solid-state reference electrode on a Si wafer" Kwang-Seok Yun, Hong-Jeong Kim, Segyeung Joo, Juhyoun Kwak and Euisik Yoon, Digest of Papers Microprocesses and Nanotechnology 2000 pp. 72
  2. "Analysis of heavy-metal-ions using mercury microelectrodes and a solid-state reference electrode on a Si wafer" Kwang-Seok Yun, Hong-Jeong Kim, Segyeung Joo, Juhyoun Kwak and Euisik Yoon, Jpn.J.Appl.Phys. Vol.39(2000) pp. 7159-7163