PEDOT: PSS composite deposited on a microplatinum electrode as a robust biosensor transducer for applications in liquid media

Over the last few decades, electrochemical transducers based on conductive polymers have received considerable attention owing to their physical and chemical characteristics with a potential to enhance the performance of an electrochemical biosensor in liquid media. Simultaneous electropolymerization and deposition of 3,4-ethylenedioxythiophene and poly(styrene sulfonate) (EDOT and PSS) on a microplatinum electrode (μPtE) surface was performed. The surface area of the electrode was varied by changing the length: 10 mm and 5 mm with a fixed diameter of 50 μm. Electropolymerization of EDOT:PSS to poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) was conducted using galvanostatic mode in a potentiostat/galvanostat at 100 μA and 400 mV. The electrochemical measurements were performed in 0.1 M potassium ferrocyanide (K3Fe(CN)6) solution. Redox currents over 6 days were measured in terms of anodic peak current using cyclic voltammetry (CV). Field emission scanning electron microscope (FESEM) results revealed the effect of liquid media on PEDOT:PSS film deposited on a higher surface area before and after measurement. Although anodic peak current did not change significantly for electrode lengths of 10 mm and 5 mm (~0.20 mA) on day one, the stability of current measurements (anodic peak current at day six in comparison to day one) decreased by 20% and 85% for 10 and 5 mm electrode lengths, respectively. This study has found that PEDOT:PSS deposited on a 5-mm microplatinum electrode with non-uniform films lost measurement stability in terms of anodic peak current after one week. However, a 10-mm microplatinum electrode with better film uniformity was able to maintain measurement stability for 2 weeks. The results enable development of PEDOT:PSS as a transducer layer deposited on microplatinum wire with a micrometer (μm) diameter for producing a robust electrochemical biosensor for applications in liquid media