Enhancing Mechanical Durability of Water-Soluble Microneedles with Cellulose Nanofibers via Thermal Imprinting

The study demonstrates the effectiveness of ultrahigh-pressure homogenizer (UHPH) cellulose nanofibers (CNFs) in improving the mechanical properties of poly(vinyl alcohol) (PVA) microneedle arrays (MNA). CNFs were incorporated into PVA nanocomposite films at concentrations of 0, 5, and 8 wt % using solvent casting and a nickel mold coated with a fluoropolymer was used to thermally imprint the films with MNA micropatterns at optimal mold temperatures and pressing pressure. The integration of CNFs substantially enhanced the morphological properties, surface modulus, and the accuracy of pattern replication in the nanocomposite. The augmented mechanical strength observed in the micropatterns, attributed to CNFs and subjected to UHPH treatment, can be ascribed to the physical entanglement and hydrogen bonding facilitating formation within the MNA micropattern.