Abstract
We report a straightforward and reproducible electrochemical approach to develop polydopamine-ethanolamine (ePDA-ETA) films to be used as immunosensing interfaces. ETA is strongly attached to polydopamine films during the potentiodynamic electropolymerization of dopamine. The great advantage of the electrochemical methods is to generate the oxidized species (quinones), which can readily react with ETA amine groups present in solution, with the subsequent incorporation of this molecule in the polymer. The presence of ETA and its effect on the electrosynthesis of polydopamine was accessed by cyclic voltammetry, ellipsometry, atomic force microscopy, FTIR and X-ray photoelectron spectroscopy. The adhesive and biocompatible films enable a facile protein linkage, are resilient to flow assays, and display intrinsic anti-fouling properties to block non-specific protein interactions, as monitored by real-time surface plasmon resonance, and confirmed by ellipsometry. Immunoglobulin G (IgG) and Anti-IgG were used in this work as model proteins for the affinity sensor. By using the one-step methodology (ePDA-ETA), the lower amount of immobilized biorecognition element, IgG, compared to that deposited on ePDA or on ETA post-modified film (ePDA/ETA), allied to the presence of ETA, improved the antibody-antigen affinity interaction. The great potential of the developed platform is its versatility to be used with any target biorecognition molecules, allowing both optical and electrochemical detection.
Highlights
We report a straightforward and reproducible electrochemical approach to develop polydopamineethanolamine films to be used as immunosensing interfaces
The incorporation of ethanolamine into polydopamine matrices, as mentioned, is envisaged as a strategy to inhibit the non-specific adsorption that occurs at the adhesive polydopamine surface, upon the immobilization of the biorecognition protein
As previously reported[15], two redox processes attributed to quinone/hydroquinone (Q/HQ) species in solution can be observed during dopamine electropolymerization in the absence of ethanolamine (Fig. 2a,c)
Summary
We report a straightforward and reproducible electrochemical approach to develop polydopamineethanolamine (ePDA-ETA) films to be used as immunosensing interfaces. Recent studies, revealed that electrosynthesis of polydopamine yield more homogeneous films with better electrochemical properties suitable for electrochemical biosensing interfaces than the standard chemical synthesis, highlighting the great potential of electrochemical methods to better tune the chemical and physical properties of p olydopamine[15,17] It was demonstrated by combining the electropolymerization processes with gravimetry[18], that PDA has a much higher affinity for immunoglobulin G (IgG) than poly(pyrrole), due to the presence of the adhesive functionalities. While the recognized adhesion properties of PDA films are a major advantage regarding the robust linkage of proteins, it can be a drawback when preparing affinity sensors, since the remaining active sites in the polymer, after bioreceptor immobilization, will be available for non-specific interactions with interferents. The control over wettability, for instance, has been successfully achieved by the creation of superhydrophilic/superhydrophobic antifouling coatings, through the addition of specific compounds (e.g. sodium periodate or copper s ulfate[21] or d iamines[22], hyaluronic acid23) during dopamine or catechol polymerization
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
