Collagen-ZnO Scaffolds for Wound Healing Applications: Role of Dendrimer Functionalization and Nanoparticle Morphology

Functionalized nanoparticle cross-linked collagen scaffolds offer improved properties to biomaterials and regenerated tissues, as influence of nanoparticle shape on collagen scaffold has received little attention. The present study evaluates the role of ZnO nanoparticle shape (sphere, rod, hexagonal, needle, flower, star, circular disk, doughnut, and cube) on collagen self-assembly. The nanoparticle was prepared by using coprecipitation method and subsequently functionalized with triethoxysilane poly(amidoamine) dendrimer generation 1 (TES-PAMAM-G(1) or G(1)) on the nanoparticle surface. The self-assembly process of collagen, facilitated by EDC-NHS cross-linking, led to stable ZnO-TES-PAMAM-G(1)-collagen scaffolds. Physicochemical properties and biocompatibility of scaffolds were analyzed to determine the thermal, mechanical and pore size transformation and cell viability, etc. and obtained results compared against collagen scaffolds with/without EDC-NHS cross-linking. In vivo wound healing activity of ZnO-TES-PAMAM-G(1)-collagen scaffolds was tested on Albino rats that were subjected to excisional wounds and results were compared with control and collagen scaffold. Our findings suggested that the functionalized nanostructure mediated collagen scaffolds exhibited higher thermal (91.2 +/- 0.3 degrees C) and mechanical stability (130.23-305.45 +/- 0.1-2.0 MPa) than collagen scaffold (77.36 +/- 0.5 degrees C and 7.96 +/- 0.8 MPa). The result of in vivo wound healing study indicated that spherical shape of ZnO-TES-PAMAM-G(1) NPs cross-linked collagen scaffold showed enhanced re-epithelization and faster collagen deposition than other scaffolds probably owing to their higher surface area, which led to higher grafting density on the surface. This work provides a new approach for designing nanoparticle mediated collagen scaffold for wound healing application.