Enhanced Thin‐Film Encapsulation Through Micron‐Scale Anchors

Abstract

Implantable medical devices require protective encapsulation to isolate them from the biological environment. Parylene‐C (PaC) is a prevalent encapsulation polymer but is susceptible to cracking, delamination, oxidation, and moisture penetration over time. This study demonstrates that 3D micro‐anchors fabricated by direct laser writing (DLW) greatly enhance PaC lifetime and encapsulation properties. The PaC film is vapor deposited onto these anchor points, followed by ultraviolet radiation (UV)‐curing‐induced shrinkage. Electrochemical impedance spectroscopy (EIS) during accelerated aging tests in reactive solutions (87 °C, 15 mM H2O2) is performed to monitor film degradation over time. Unpatterned PaC films failed before reaching the 3.25 accelerated year benchmark, while 100 µm spaced micro‐anchors extended encapsulation up to 5.5 equivalent years. Subsequent improvements are achieved with a spacing of 50 µm, demonstrating viability up to ≈6 equivalent years. This research demonstrates the benefit of engineering anchor points for preventing delamination of the PaC layer and significantly enhancing encapsulation properties. Printed 3D micro‐anchors are an extremely flexible platform, with many different shapes and sizes possible which can further enhance longevity. The success in increasing coating lifetimes offers a promising direction for improving long‐term implantable medical devices, potentially revolutionizing their longevity and reliability.