Water-based, surfactant-free cytocompatible nanoparticle-microgel-composite biomaterials – rational design by laser synthesis, processing into fiber pads and impact on cell proliferation

This work highlights the laser-based aqueous synthesis and processing of nanocomposites, composed of zinc or iron nanoparticles embedded in a N-Vinylcaprolactam microgel matrix, with potential applicability as ion releasing fiber pads for wound healing. An in situ laser process for microgel synthesis is developed and optimized for high embedded nanoparticle yields, evaluating influences of laser repetition rate and monomer concentration. The impact of the nanoparticles on polymerization was increased by embedded zinc oxide nanoparticles, and reduced in the presence of iron oxide. Furthermore, TEM images verified that the nanoparticles were homogeneously embedded into the polymer matrix. The nanoparticle-loaded microgels were thermally stable up to 429 °C, which ensures that the composites maintain their integrity after heat sterilization and during rapid prototyping by thermal polymer processing. The general suitability of the hydrogels as active biomaterial for wound healing was assessed in toxicity, cell proliferation and migration assays using human dermal fibroblasts and keratinocytes, where cytocompatibility was verified, while the proliferation was affected by the gel alone as well as the embedded nanoparticles. The hydrogels were processed to suit their use as a biomaterial for wound coverages via electrospinning resulting in a centimeter scale fully cytocompatible fiber pad with the nanoparticle-filled microgel capsules supported on the fiber’s surface.