Development of biomimetic antimicrobial platelet-like particles comprised of microgel nanogold composites.

A blood clot is formed in response to bleeding by platelet aggregation and adherence to fibrin fibers. Platelets contract over time, stabilizing the clot, which contributes to wound healing. We have developed platelet-like particles (PLPs) that augment clotting and induce clot retraction by mimicking the fibrin-binding capabilities and morphology of native platelets. Wound repair following hemostasis can be complicated by infection; therefore, we aim to augment wound healing by combining PLPs with antimicrobial gold to develop nanogold composites (NGCs). PLPs were synthesized with N-isopropylacrylamide (NIPAm)/co-acrylic acid in a precipitation polymerization reaction and conjugated to a fibrin-specific antibody. Two methods were employed to create NGCs: 1) noncovalent swelling with aqueous gold nanospheres, and 2) covalent seeding and growth. Since the ability of PLPs to mimic platelet morphology and clot retraction requires a high degree of particle deformability, we investigated how PLPs created from NGCs affected these properties. Cryogenic Scanning Electron Microscopy (cryoSEM) and atomic force microscopy (AFM) demonstrated that particle deformability, platelet-mimetic morphology and clot retraction were maintained in NGC-based PLPs. The effect of NGCs on bacterial adhesion and growth was assessed with antimicrobial assays. These results demonstrate NGCs fabricated through noncovalent and covalent methods retain deformability necessary for clot collapse and exhibit some antimicrobial potential. Therefore, NGCs are promising materials for preventing hemorrhage and infection following trauma.