Keywords: polypyrrole, PPy, biomolecules, impedance, conducting polymers, biomedical engineering, biomaterials, biosensors, cell adhesion, cell migration, metabolite monitoring
Polypyrrole incorporating biomolecules
Polypyrrole (PPy) is a conducting polymer with emerging applications in biomedical engineering. We report on the synthesis and properties of PPy incorporating biomolecules using AC impedance spectroscopy. Impedance behaviour was consistent with two basic charge transfer processes, polaronic and electronic, demonstrated by two-electrode impedance spectroscopy over the frequency range 5 Hz?13 MHz. These processes were sensitive to alterations in environmental conditions such as pH and ionic strength. The reported results are likely to be a consequence of the intimate molecular association between PPy chains and incorporated molecules in the matrix as evidenced by variations in impedance spectra related to polymer loading. PPy incorporating physically entrapped biomolecules together with impedance spectroscopy could be exploited in reagentless biosensor applications. Furthermore, this could be coupled to their emerging role in cell contact and guidance applications for the detection of cell adhesion, migration or metabolite monitoring.