Growth of continuous bonelike mineral within porous poly(lactide-co-glycolide) scaffolds in vitro

Strategies to engineer bone have focused an the use of natural or synthetic degradable materials as scaffolds for cell transplantation or as substrate s to guide bone regeneration. The basic requirements of the scaffold materi al are biocompatibility, degradability, mechanical integrity, and osteocond uctivity. A major design problem is satisfying each of these requirements w ith a single scaffold material. This study addresses this problem by descri bing an approach to combine the biocompatibility and degradability of a pol ymer scaffold with the osteoconductivity and mechanical reinforcement of a bonelike mineral film. We report the nucleation and growth of a continuous carbonated apatite mineral on the interior pore surfaces of a porous, degra dable polymer scaffold via a one step, room temperature incubation process. A 3-dimensional, porous scaffold of the copolymer 85:15 poly(lactide-co-gl ycolide) was fabricated by a solvent casting, particulate leaching process. Fourier transform IR spectroscopy and scanning electron microscopy (SEM) a nalysis after different incubation times in a simulated body fluid (SBF) de monstrate the growth of a continuous bonelike apatite layer cz within the p ores of the polymer scaffold. Quantification of phosphate on the scaffold d isplays the growth and development of the mineral film over time with an in corporation of 0.43 mg of phosphate (equivalent to 0.76 mg of hydroxyapatit e) per scaffold after 14 days in SBF. The compressive moduli of polymer sca ffolds increased fivefold with formation of a mineral film after a 16-day i ncubation time as compared to control scaffolds. Ln summary, this biomimeti c treatment provides a simple, one step, room temperature method for surfac e functionalization and subsequent mineral nucleation and growth on biodegr adable polymer scaffolds for tissue engineering. (C) 2000 John Wiley & Sons , Inc.