Fabrication and structural characterization of porous biodegradable pply(DL-lactic-co-glycolic acid) scaffolds with controlled range of pore sizes

Biodegradable polymer scaffolds play a major role in the field of tissue engineering as they provide a three-dimensional template to regenerate desirable tissues for different applications. In this study, porous Poly(DL-lactic-co-glycolic acid) (PLGA) scaffolds with four different pore sizes (150-180 mum, 180-250 mum, 250-280 mum and 280-400 mum) were fabricated using paraffin-spheres-dissolution technique. Paraffin spheres with the stated size range were bonded into a layer through a heat treatment to form a three-dimensional assembly. Biodegradable polymer PLGA (50/50) was dissolved in pyridine and cast into the paraffin sphere assembly. After dissolving the paraffin spheres, a porous polymer scaffold was formed. The morphology of the porous PLGA scaffolds was examined using scanning electron microscopy (SEM). Results showed that all four PLGA scaffolds had apparently uniform pore morphology with different pore diameters. The pores were mostly interconnected with diameters lying within the pore size range. Mercury intrusion porosimetry was also used to determine the median pore diameter, surface to volume ratio and the total porosity of the scaffolds. As compared with the size of the paraffin spheres used to generate the scaffolds, the median pore diameters measured by mercury porosimetry were smaller. This discrepancy could be explained by the presence of the smaller pores formed from the paraffin residues during dissolution and that the space between the paraffin spheres are not completely filled by the polymer before extraction. As the pore size range of the PLGA scaffolds increased, similar values of the surface to volume ratio were observed. All four different PLGA scaffolds are highly porous having nearly 90% porosity. It is believed that these parameters would significantly affect the transport processes through the scaffold as well as the structural properties of the scaffold. (C) 2004 Elsevier Ltd. All rights reserved.