Fabrication of High Aspect Ratio Optical/Electrochemical Hybrid Sensor Arrays

Tufts University, Medford MA

Investigators

Abstract

Professor David Walt of Tufts University is supported by the Analytical and Surface Chemistry Program to create a microsensor platform that can make simultaneous electrochemical and optical measurements. The major objective is to demonstrate the feasibility of performing multiplexed analysis using electrochemiluminescence (ECL). The PI has pioneered the use of random optical arrays for multiplexed analysis. In this project, the PI is creating a hybrid optical and electrochemical sensor array by deposition of gold in micron-diameter, open silica capillaries, which also function as optical fibers. Optical microbeads will be prepared, inserted into wells in the fibers and excited by an electropotential applied through the microwires. The resulting emitted light will be collected through the fiber. The beads are coated with conducting polyaniline or polypyrrole so that they can be functionalized to detect various species. The long-term goal involves the creation of a universal platform in which either optical or electrochemical (or both types of) sensors can be interrogated individually in an array format. The coupling of electrochemistry and spectroscopy increases the amount of information that can be obtained from a given sensor, preventing false positives. There is a great need for next generation sensors that can detect numerous species accurately and inexpensively. The integrated platform being created in this project will allow applications in the clinical, environmental and chemical and bioprocess control areas. The array platform should enable new types of chemical imaging measurements with micrometer spatial resolution, which could be used in medical diagnostics and the study of biological cells. This research exposes students to several disciplines including chemistry, optics, physics and biology.