Nanostructured Effect on Antifouling Conducting Polymers through Interfacial Adhesive Interaction and Protein Adsorption

Antifouling properties are indispensable for ensuring the efficiency of biomedical applications in biotechnology. Bioinspired antifouling surfaces have undergone significant development. The adhesive interactions of nanopatterns supply localized force-related data. In this study, a precisely defined conducting polymer (CP), poly(3,4-ethylenedioxythiophene) (PEDOT), was enriched with antifouling phosphorylcholine moieties (PEDOT-PC) for comparison with hydroxyl-functionalized PEDOT (PEDOT-OH) to investigate their effects. Well-defined nanopatterned PEDOT films can be precisely created by controlling the electropolymerization process on a polystyrene (PS) monolayer template using a colloidal lithography approach. Electropolymerized PEDOT coatings have emerged as a surface modification strategy for bioelectrodes due to their facile functionalization and fabrication. The patterns are versatile, depending on the sizes of PS beads and electropolymerization conditions. Atomic force microscopy (AFM) allows for the examination of the adhesion effects of periodic nanostructures in aqueous solutions. Real-time and quantitative assessment of adhesion between the AFM tip and the sample was conducted through force-volume mapping. Furthermore, the study involved the examination of protein adsorption behaviors at these interfaces using a quartz crystal microbalance with dissipation (QCM-D), including bovine serum albumin (BSA), cytochrome c (cyt c), lysozyme (LYZ), and C-reactive protein (CRP). AFM probing near the interface revealed that surface morphology induced higher adhesion forces than pristine polymer films, whereas the PEDOT-PC coating exhibited minimal interaction during tip scanning. Additionally, protein adsorption tests indicated that the nanostructures compromised the antifouling properties of PEDOT-PC films, aligning with water contact angle measurements. The periodic structure enhances the energy barrier, disrupting the preservation of a continuous water layer captured by the PC moieties. Our research offers a straightforward approach to creating a nano CP template suitable for various systems. Moreover, it provides a deeper understanding of the physical investigation and the implications of biomolecule responses of the nanostructure effects using AFM and QCM-D.