Preclinical alternative model for analysis of porous scaffold biocompatibility in bone tissue engineering

Abstract

Porous scaffolds represent a potential approach to repair critical-size bone defects. Vascularization is essential for bone formation and healing. This study establishes a method to monitor angiogenesis within porous biopolymer scaffolds made on the basis of polyhydroxybutyrate and chitosan. We used the chick and quail chorioallantoic membrane (CAM) assay as an alternative in vivo model to study the formation of new blood vessels inside the scaffold structure. The chemical properties of the biopolymer scaffold matrix surface were characterized as well as the tissue reaction of the CAM. Placing a piece of polymer scaffold on the CAM resulted in a vascular reaction documented visually and by ultrasound biomicroscopy. Histological analysis showed a myofibroblast reaction (smooth muscle actin-positive cells) without excessive collagen deposition. Cell invasion into the implant was observed and the presence of a vascular network was confirmed by identifying hemangioblasts and endothelial cells of quail origin using the QH1 marker. The CAM assay is a rapid and easy way to test biocompatibility and vasculogenic potential of new candidate scaffolds for bone tissue bioengineering while respecting the 3Rs.