Work

Photoinitiated CVD antifouling coatings enable long-term stability of flexible multifunctional neural probes for chronic neural recording

Year: 2025

Type: article

Abstract: Flexible neural probes with integrated recording, optical stimulation, and drug delivery capabilities offer unprecedented access to neural circuit dynamics. However, their long-term utility is compromised by foreign body responses that isolate recording sites from target neurons. This study introduces photoinitiated chemical vapor deposition (piCVD) as a transformative approach to neural interface stability through ultrathin (<100 nm) anti-fouling coatings. Unlike conventional hydrogel coatings that impair electrical signal transmission, our piCVD-applied poly(2-hydroxyethyl methacrylate-co-ethylene glycol dimethacrylate) coating maintains electrical functionality by preserving low impedance while providing superior anti-fouling properties. In vitro protein adsorption studies demonstrated near-complete resistance to both albumin and fibrinogen compared to uncoated surfaces, with the coating maintaining stability even after 24 h of sonication-durability unachievable with conventional wet-chemistry methods. When evaluated in mouse models over three months, the coated probe maintained high-quality spontaneous neural recordings and optically evoked potentials throughout the study period, with signal-to-noise ratios improving from 18.0 at week 1-20.7 at week 13. This performance significantly correlates with 66.6 % reduction in glial scarring, 84.6 % increase in neuronal preservation compared to uncoated probes. The specific combination of CVD methodology and optimized copolymer composition achieves long-term stability, representing a significant advance over the typical one-month limitation of conventional coatings. These results establish piCVD antifouling coatings as an enabling technology for chronic neural interfaces in both basic neuroscience research and emerging neuroprosthetic applications.

Source: Biomaterials

DOI: 10.1016/j.biomaterials.2025.123554