Adenosine 5'-triphosphate incorporated poly(3,4-ethylenedioxythiophene) modified electrode: a bioactive platform with electroactivity, stability and biocompatibility

Poly(3,4-ethylenedioxythiophene) (PEDOT) was potentiostatically polymerized onto gold electrode with adenosine 5'-triphosphate (ATP), an important biomolecule, as the counterion. Essential parameters to affect the impedance of the resultant polymer were studied in detail. Results show that 1.0 V, 0.1 M and 2.2 mC is the optimal deposition potential, dopant concentration and quantity of the passing charges, respectively. Surface topography was studied by AFM and the relationship between impedance and topography was discussed. Spontaneous release of ATP from PEDOT matrix was examined using UV-visible spectroscopy and impedance variation of the polymer modified electrode was monitored with electrochemical impedance spectroscopy. The results indicate that ATP could be strongly bound with the polymer in the incubation medium and thus could realize its role as a cell binder in its implantable application. In vitro test further demonstrates that PC12 cell could adhere to and grow on the PEDOT/ATP modified electrode and cell attachment percentage was much higher than that of non-biomolecule doped PEDOT modified electrode. Moreover, stability of PEDOT/ATP in the biological reducing agent of glutathione (GSH) was much better than that of polypyrrole/ATP. Our work demonstrates that PEDOT/ATP modified electrode can be of a promising bioactive platform to be used for implantable neural recording devices due to its great stability and biocompatibility.