A polylactide/fibrin gel composite scaffold for cartilage tissue engineering: fabrication and an in vitro evaluation

A composite scaffold for cartilage tissue engineering was fabricated by filling a porous poly (l-lactide) (PLLA) scaffold with fibrin gel. The porous PLLA scaffold prepared by a method of thermally induced phase separation has an average pore diameter of 200 mu m and a porosity of 93%. Incorporation of fibrin gel into the scaffold was achieved by dropping a fibrinogen and thrombin mixture solution onto the scaffold. For a couple of minutes the fibrin gel was in situ formed within the scaffold. The filling efficiency was decreased along with the increase of the fibrinogen concentration. After fibrin gel filling, the compressive modulus and the yield stress increased from 5.94 MPa and 0.37 MPa (control PLLA scaffold in a hydrated state) to 7.21 MPa and 0.53 MPa, respectively. While the fibrin gel lost its weight in phosphate buffered saline up to 50% within 3 days, 85% and 70% of the fibrin gel weight in the composite scaffold was remained within 3 and 35 days, respectively. A consistent significant higher level of rabbit auricular chondrocyte viability, cell number and glycosaminoglycan was measured in the composite scaffold than that in the control PLLA scaffold. Rabbit auricular chondrocytes with round morphology were also observed in the composite scaffold by confocal microscopy and scanning electron microscopy. Altogether with the features of better strength and cytocompatibility, this type of composite scaffold may have better performance as a matrix for cartilage tissue engineering.