Two Photon Polymerization of Polymer–Ceramic Hybrid Materials for Transdermal Drug Delivery

TLDR

Femtosecond laser two‑photon polymerization of Ormocer hybrid materials was used to fabricate arrays of in‑plane and out‑of‑plane hollow microneedles (800 µm long, 150–300 µm base) and their fracture and penetration properties were evaluated by compression load testing. The fabricated microneedles penetrated cadaveric porcine adipose tissue without fracture, maintained keratinocyte viability comparable to controls, and demonstrate that two‑photon polymerization enables transdermal drug‑delivery microneedles with a broader range of geometries than conventional techniques.

Abstract

Three‐dimensional microneedle devices were created by femtosecond laser two photon polymerization (2PP) of organically modified ceramic (Ormocer®) hybrid materials. Arrays of in‐plane and out‐of‐plane hollow microneedles (microneedle length=800 μm, microneedle base diameter=150–300 μm) with various aspect ratios were fabricated. The fracture and penetration properties of the microneedle arrays were examined using compression load testing. In these studies, the microneedle arrays penetrated cadaveric porcine adipose tissue without fracture. Human epidermal keratinocyte viability on the Ormocer® surfaces polymerized using 2PP was similar to that on control surfaces. These results suggest that 2PP is able to create microneedle structures for transdermal drug delivery with a larger range of geometries than conventional microfabrication techniques.