Nanofibrous (NF) mats have shown great promise to facilitate wound healing. In this work, we aim to engineer a NF-based scaffold for hard-to-heal diabetic ulcers. Specifically, we explore the surface modification of polycaprolactone/collagen NFs with ultrathin coatings of polymeric micelles and natural antioxidant molecules as a means to modulate NF topography, tune antioxidant capabilities, and modulate cellular responses to aid wound healing. Multilayers of polymeric micelles, composed of poly(acrylamide-<i>co</i>-acetonitrile) cores and polyvinylpyrrolidone coronae, were deposited onto fibers by assembly with tannic acid (TA), which possesses anti-inflammatory and pro-wound healing effects. Such micellar coatings display dense coverage of micelles on fiber surface, and show layer-dependent topography and radical-scavenging capability enabled by TA. Upon exposure to serum, micelles detached from the NF surface between 4 and 6 days of culturing <i>in vitro</i>. Free micelles in solution had negligible effects on macrophage viability but induced a transition in phenotype from M0 to M1 upon intracellular uptake. A similar modulation of macrophage phenotype was observed for macrophages cultured on micelle/TA-coated NFs, which exhibited more M1 phenotype (iNOS positive) compared to those on bare NF mats, which showed more M2 phenotype (CD206 positive). In addition, micellar coatings on NF are also attractive because of the availability of the functional upper critical solution temperature micellar cores, which allow the loading and controlled release of small bioactive molecules (such as pioglitazone hydrochloride) critical for tissue regeneration and wound healing.

Surface modification of nanofibrous mats with polymeric micelles for enhanced tissue regeneration

2019 Fall National Meeting

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