Toxic heavy metals are a growing threat to global environmental health. Heavy metals may enter the human body in food, water, or air, or by absorption through the skin. Once in the body, they compete with and displace essential minerals and interfere with organ system function, thus causing a variety of diseases. To respond to these growing problems, there has been a large demand for the development of devices for environmental health monitoring, which are capable of fast, reliable, and accurate measurement of heavy metals in a portable platform.
In this research, a microfabricated electrochemical sensor with planar bismuth electrode for heavy metals measurement using anodic stripping voltammetry has been designed, fabricated, characterized, and applied to environmental health monitoring. By developing as a microfluidic polymer lab-on-a-chip (LOC), which is incorporated into a portable analyzer, on-site continuous sampling and monitoring of the contamination of heavy metals can be realized. The sensor has also been applied for on-chip monitoring of cadmium (Cd) concentration in an integrated cells-on-a-chip platform to perform Cd cytotoxicity test.
Compared with previous work, this research is mainly focused on using standard BioMEMS fabrication technology to develop an environmentally-friendly, ready-to-use solid-state sensor that can perform rapid heavy metals measurement in natural- or biological-environments without disturbing the sensing environment and media. Moreover, this on-chip sensor can be easily adapted into different LOC platforms or incorporated with analyzers for carrying out heavy metals measurement to meet various demands in environmental health monitoring.
In this research, multiple parameters that can affect on the sensor's performance have been explored and fully investigated. The sensor has been characterized and optimized based on experimental results, and applied to environmental monitoring applications. To perform automatic and continuous sampling and monitoring, a battery-powered portable analyzer, along with a polymer LOCs array, has been developed and tested. In addition, as another important application in environmental heath, the electrochemical sensor for heavy metals has also been integrated into a polymer cells-on-a-chip, which can perform on-chip cell culture and viability monitoring for heavy metals cytotoxicity test.