Aptamer-based capacitive biosensors enable label-free neurotransmitter detection, yet reproducible aptamer-functionalized interfaces remain challenging to achieve. Therefore, interface engineering strategies enabling well-controlled, aptamer-compatible polymer thin films are required.
To address this issue, we fabricated amine-reactive poly(2-hydroxyethyl methacrylate-co-pentafluorophenyl methacrylate) copolymer thin films via photo-initiated chemical vapor deposition, enabling solvent-free, conformal nanoscale coatings with controlled composition. The pentafluorophenyl ester units enable covalent aptamer immobilization, while the hydroxy component regulates surface hydrophilicity and interfacial properties relevant to capacitive transduction.
Variation of copolymer composition demonstrated that balancing reactive group density and surface wettability is essential for stable biofunctionalization, enabling reliable capacitive responses when applied as anchoring layers on electrodes.