Oxidative Chemical Vapor Deposition (oCVD) Synthesis of Molecularly Imprinted Polypyrrole Nanotube for the Detection of CA-125 Protein

Field-effect transistor (FET) based biosensors have been widely used in various applications such as medical diagnosis, health and environmental monitoring. The performance of the FET biosensors are determined by anchoring specific probes on the conducting channel for target biomolecules. In the past two decades, molecularly imprinted polymers (MIPs) have attracted much attention as a robust and cost-effective alternative to natural bioreceptors such as enzymes and antibodies. MIPs are artificial template-made receptors which have the ability to recognise specific target molecules. Here, we present a novel FET biosensor incorporated with a molecularly imprinted polypyrrole nanotube (MIPN) for the selective detection of CA-125 ovarian cancer biomarkers. Polypyrrole (PPy) nanotube used in the FET biosensor has been obtained via oxidative chemical vapor deposition (oCVD) which is a highly efficient solvent-free, vacuum-based technique for the synthesis of conductive polymers. Thanks to the flexibility of this method, MIPN has been conveniently synthesized by coating conformally the sacrificial porous structured templates in the presence of target protein. Particularly, imprinting the target molecule on the nanotube surface has provided extremely high surface area which leads to enhancement in selectivity of the sensor. Furthermore, the oCVD synthesis has enabled higher electrical conductivity for the resulting PPy nanotube by tuning deposition parameters such as oxidant/monomer ratio, substrate temperature and reaction pressure. Synthesized MIPN has been integrated onto the interdigitated array Au electrode to make a conductive bridge between source and drain terminals and biosensor platform has been assembled from chip device, microfluidic channel and custom made chip holder for real-time measurement. The present study has provided useful insight into preparing a novel molecularly imprinted polymer nanotube with various target protein molecules by using oCVD technique.<br/><br/><b>Acknowledgments</b><br/>This work was supported by the Scientific and Technological Research Council of Turkey (TUBITAK), Grant No: 119Z342.<br/><br/><b>Keywords: </b>oxidative chemical vapor deposition, molecularly imprinted polymer, polypyrrole nanotube, FET biosensor