Microneedles (MNs) for electrochemical biosensing have emerged as a promising platform for minimally invasive diagnostics, enabling access to interstitial fluid while reducing the discomfort associated with conventional blood sampling. Among the strategies used to develop conductive MNs, the incorporation of conductive polymers, such as poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), stands out for its high conductivity, biocompatibility, and stability in aqueous media. However, achieving stable, homogeneous coatings on polymeric substrates remains a major challenge, largely due to poor interfacial adhesion and differences in surface chemistry. In this context, this work proposes the development and comparative evaluation of conductive microneedle platforms based on PCL/PDA/PVA-PEDOT:PSS and PLA/PDA/PVA-PEDOT:PSS architectures, with emphasis on how substrate properties influence polymer adhesion, mechanical performance, and electrochemical behavior. To overcome interfacial limitations, the microneedle surfaces were modified with polydopamine (PDA) as a bioinspired adhesion-promoting layer. PEDOT:PSS coatings were then deposited via in situ oxidative polymerization using EDOT, PSS, ammonium persulfate, and FeCl3, with poly(vinyl alcohol) (PVA) incorporated as a hydrophilic co-matrix to improve film formation and cohesion. The resulting systems were characterized by compression assays, while electrochemical performance was evaluated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results showed that PDA priming significantly improved polymer anchoring and that combining PDA with PVA-assisted polymerization produced uniform, stable, and adherent PEDOT:PSS coatings. Electrochemical measurements revealed a substantial reduction in charge-transfer resistance (Rct ? 395 ?), indicating improved electron-transfer kinetics compared with previously reported systems. Mechanical analysis showed that surface modification increased the effective stiffness of PCL-based microneedles, improving their resistance to compression-induced deformation. Comparative evaluation further showed that PLA-based microneedles exhibited higher Young’s modulus, sharper tip geometry, and improved aspect ratios, suggesting greater mechanical robustness and insertion capability, whereas PCL-based systems showed greater flexibility and successful coating integration. Both platforms displayed well-defined redox behavior, confirming their electrochemical activity and suitability as sensing interfaces.
Comissão Organizadora
Pedro Alves da Silva Autreto
Comissão Científica
Ferramenta completa de submissão, avaliação e publicação de anais para eventos científicos.
