Researcher(s)
- Anna Houpt, Chemistry, University of Delaware
Faculty Mentor(s)
- Laure Kayser, Material Science, University of Delaware
Abstract
Biosensors are becoming increasingly important due to their many applications such as disease detection and drug discovery, prompting the development of devices with better performance. Organic electrochemical transistors (OECTs) are a type of biosensing device that transports both ions and electrons through a polymeric semiconductor channel, or organic mixed ionic-electronic conductor (OMIEC). Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) is a benchmark OMIEC that is commonly used in OECTs, because of its high transconductance and low voltage operation. While these properties make it an effective OMIEC for biosensing applications, further research is needed to enhance its performance. We believe that OECT performance can be enhanced by optimizing PEDOT:PSS properties such as volumetric capacitance by porosity and improving stability through adding a zwitterionic polymer. To create a porous film, polystyrene (PS) microspheres were mixed into PEDOT:PSS and spincoated onto films, then removed with an organic solvent to create voids in the film. This procedure creates a greater surface area and allows for better ion transport, enhancing volumetric capacitance. Another method involves incorporating a zwitterionic polymer, poly[1-(3-sulfopropyl)-2-vinylpyridinium] (PSB4VP). Zwitterionic polymers are promising for biomedical devices because of their high polarity, overall neutral charge, and antifouling. To create a zwitterionic OMIEC, SB4VP was copolymerized with PSS, and followed by the polymerization of PEDOT. Microscopy proved the removal of the PS spheres with toluene, and the zwitterionic polymer was successfully synthesized. Future work will involve incorporating this polymer and the porous film into an OECT to evaluate their performance in comparison to that of a conventional PEDOT:PSS-based OECT. If successful, these approaches could be applied to develop more efficient biosensors for a wide range of medical applications.