Electrochemical Sensors for Biological and Environmental Application

Abstract

Electrochemical sensors have been developed for last few decades in many different types and ways. They can be applied in various fields of study such as biomedical or biomaterials, environment, and energy, etc. Few projects will be introduced in the conference to show how these sensors can solve such problems. One of the sensors we’ve developed is used to quantify pH and H2O2 simultaneously in real-time to study oral bacterial metabolism in micro-environment. One species of oral bacteria takes glucose and produces H2O2 which plays a key role in maintaining healthy oral condition. We assume that the H2O2 production will increase at higher pH. Since bacterial metabolism and interspecies interaction occurs in few-micron surrounding from bacterial community, it is very challenging to approach there without destroying samples. Thus, we are using few techniques here; Scanning electrochemical microscopy enables us to control and fix the distance between a substrate and an extremely small microelectrode. Another sensor we are working on has unique composition of ion-selective electrode (ISE) membrane. ISE membrane is primarily made of insulating PVC that limits its use as an amperometric electrode. However, our sensor has a carbon-based dual function ISE membrane. It is capable of switching between amperometric and potentiometric measurements without affecting the selectivity coefficients of ISEs. It showed an impressive nM and pM detection limit of Cu2+ and thus opening new avenues of exploiting the excellent selectivity of ISEs and low detection limit of ASWSV techniques. This sensor can be applied to trace heavy metal ions concentration in unknown liquid sample and to determine their solubility depending on pH. The design of sensor and experimental setup will be presented.