Electrochemical behavior of oxazoline‐based plasma polymers for biosensing applications

Abstract

Plasma‐polymerized polyoxazoline (POx) thin films offer a fast, scalable, and solvent‐free method of electrode functionalization through the unique chemistry of the oxazoline ring. However, for POx to be a viable green alternative to existing surface modification approaches, the films should be able to withstand the processing steps involved in biosensing. Here, the effects that current exposure, extended incubation, and repeated electrode rinses have on the electrochemical and physical stability of polymethyloxazoline thin films are investigated. The films are observed to become more diffusive after incubation and rinse steps. While no significant changes in chemistry were observed, a marked change in nanotopography occurred after exposure to current, suggesting a change in the polymer film structure.

Hydrophobic Coatings with Charge Permeability via Plasma Deposition of Long-Chain Perfluorocarbons

“…The exposed electrode area for the measurements was 1.767 cm 2 . The CV tests were conducted in a custom-made single-cell setup with a Pt wire as a counter electrode and a Ag/AgCl reference electrode . All potentials reported were calibrated to a reversible hydrogen electrode (RHE) by E (RHE) = E (Ag/AgCl) + 0.195 V + 0.0591 × pH.…”

“…The CV tests were conducted in a custom-made single-cell setup with a Pt wire as a counter electrode and a Ag/AgCl reference electrode. 41 All potentials reported were calibrated to a reversible hydrogen electrode (RHE) by E(RHE) = E(Ag/AgCl) + 0.195 V + 0.0591 × pH. Two sets of conditions were investigated: mild and harsh conditions.…”

“…The elution of loosely bound monomer fragments from plasma polymers is not uncommon and has been reported for films produced in the same reactor. 41 Another possible explanation is that the insulating nature of the coating is, in this case, decreasing the rate of the water-splitting reaction so much that it becomes similar to that of the diffusion rate between the applied voltage of −0.75 and 0.95 V, resulting in the observed current plateau. When the cathodic potential is applied beyond −0.95 V, the water-splitting rate increases, resulting in the onset of a current slope.…”

Enhancing the conductivity of plasma polymer functionalized electrodes using gold nanoparticles

“…6,7 Electrochemical investigations have shown that the intrinsic structure of the POx films significantly influences the charge transfer resistance of the coating independently of the film thickness. 8 Importantly, careful optimization of the deposition conditions was required to balance the POx films’ electrochemical performance and their stability to external processing, such as incubation steps, rinse cycles, and repeated current exposure.…”

Comparison of Plasma-Polymerized Thin Films Deposited from 2-Methyl-2-oxazoline and 2-Ethyl-2-oxazoline: I Film Properties

“…POxs are promising platforms for drug delivery applications due to their biocompatibility and stealth properties [6]. Plasma-polymerized POx thin films from oxazoline precursors were investigated and optimized as an alternative approach for electrode functionalization for electrochemical immunosensors [7,8]. Currently, there are many applied studies related to the water solubility, invisibility and thermoresponsive of POxs.…”