Fabrication of polycaprolactone scaffolds filled with cell-compatible porous matrix for enhanced cell growth for biomedical applications

In this study, polycaprolactone (P) scaffolds are fabricated by 3D-printing method, and subsequently a mixed solution of natural-biocompatible chitosan (C), gelatin (G), and hydroxyapatite (H) is filled into the pores of P scaffolds. Freeze-gelation method is then carried out to successfully form a cell-compatible porous CGH matrix within P scaffold pores, obtaining a newly fabricated scaffold called CGH/P composite scaffold which has large specific surface area favorable for cell attachment and growth. The effects of slow cooling (sc) and fast cooling (fc) modes utilized in freeze process on pore structures of CGH matrix are observed via SEM. The use of fc mode creates a CGH matrix with a laminar structure which benefits nutrient permeation and cell migration. Mechanical properties tests indicate that the maximum compressive strength and Young's modulus of CGH/P-fc scaffolds are 2-7 and 15-35 MPa, respectively. Cell compatibility tests show that on day 7, the cell numbers in the CGH/P-fc scaffolds are about twofold of those in the P scaffolds, and the cell activities in the CGH/P-fc scaffolds are even higher, indicating that the presence of laminar porous CGH matrix within P scaffold pores substantially enhances the migration, attachment, and growth of cells in the scaffolds. The results suggest that the fabricated CGH/P-fc composite scaffold is highly promising for biomedical applications such as bone repair in the future.