Polymer semiconductors as a biosensing platform: peroxidase activity of enzyme bound to organic semiconducting films

Organic polymer semiconductors have unique electronic properties which make them attractive for use in microelectronic and optoelectronic devices fabricated using inexpensive manufacturing processes. In addition, novel chemical and biological sensors have been proposed which make use of the photophysical and electrical properties of conjugated polymer semiconducting films. The work described herein illustrates one such biosensing application by demonstrating successful immobilization of horseradish peroxidase enzyme onto a thin film of the semiconducting polymer MDMO-PPV. Validation of bound peroxidase activity is accomplished through the use of a substrate solution of 3,3'-diaminobenzidine and hydrogen peroxide, which yields a dark brown precipitate in the presence of peroxidase. Photometric measurements are used to derive a quantitative assay of bound peroxidase concentration. This work supports the feasibility of organic semiconducting polymer films as a biosensing platform in microelectronic sensor devices.