Incorporation of poly(lactide-co-glycolide) microparticles in collagen-based scaffolds for tissue engineering applications.

In tissue engineering field, the production of a porous resorbable matrix, termed scaffold, allows to host cells and guide them towards the synthesis of physiological tissue. Porous scaffolds provide mechanical stability and an initial framework for migrating cells and vascular infiltration. Sustained delivery of bioactive molecules at the defect site may be also particularly important for tissue regeneration. In this context, the goal of this work was the fabrication of highly porous collagen-based scaffolds incorporating uniformly dispersed poly(lactide-co-glycolide) (PLGA) microparticles as depots for the sustained and localized delivery of bioactive molecules. Collagen scaffolds loaded with different amounts of PLGA-microparticles were prepared by freeze-drying and crosslinking. The scaffolds microstructure was assessed to evaluate the spatial distribution of microparticles and the achieved pore size. The impact of the microparticles on the scaffolds stiffness was investigated through compression tests. Preliminarily, the cell-microparticles interactions were also evaluated by imaging of cell morphology in vitro, adopting a human derived epithelial cell model. The experimental findings showed that collagen scaffolds with different amounts of uniformly dispersed PLGA-microparticles were successfully produced. The microparticles did not negatively affect the scaffold porous structure, while acting as a mechanical reinforcement. Additionally, microparticles show high permissiveness to cell adhesion, and the interactions between microparticles and epithelial cell membranes did not interfere with the correct cells morphological differentiation. Such promising results suggest the potential of the developed scaffolds for tissue engineering applications.