Electrospun dual-porosity structure and biodegradation morphology of Montmorillonite reinforced PLLA nanocomposite scaffolds.

Combining a nanocomposite technique and the electrospinning process, a robust dual-porosity scaffold structure was developed for a facile transport of metabolic nutrients and wastes through the nano-sized pores and for the cell implantation and blood vessel invasion through the micro-sized pores. The montmorillonite (MMT) nano-sized platelets were incorporated into poly(L-lactic acid) (PLLA) solution, which was subsequently electrospun and mechanically entangled by a cold compression molding process for a robust 3-dimensional scaffold structure. Using a salt leaching/gas forming method, micro-sized pores were developed in the electrospun fiber bundles giving a dual-porosity scaffold structure. Compared with the pristine PLLA scaffold, the developed nanocomposite fibrous scaffold structure exhibited increased strength and improved structural integrity during the biodegradation process. The nanocomposite scaffold systems also exhibited many tiny pinholes desirably generated on the scaffold walls without serious fragmentation during biodegradation reactions.