Surface Modification of PLA Nanofibers for Coating with Calcium Phosphate

Abstract

In recent years, three-dimensional scaffolds have attracted great attention due to the development of stem cell tissue engineering. It is expected that the combination of three-dimensional scaffolds and stem cells will be a promising therapy for large defects of tissue such as bone. We have been developing three-dimensional scaffolds by coating poly-lactic acid (PLA) nanofibers with hydroxyapatite (HAp; Ca₁₀(PO₄)₆(OH)₂). Although PLA, a biodegradable polymer, is used in many biomaterials and HAp has great biocompatibility, PLA nanofibers are difficult to coat with HAp due to its hydrophobic property. Calcium phosphate deposition requires hydrophilic groups such as carboxyl groups, which play a key role as calcium phosphate nucleation sites. Hence, in this work, the surface of PLA nanofibers was modified by vacuum ultraviolet (VUV) irradiation or by co-electrospinning with gelatin as a hydrophilic polymer to increase the number of calcium phosphate nucleation sites. The deposition behavior of calcium phosphate on the VUV irradiated PLA nanofibers was facilitated in comparison with the pristine nanofibrous PLA matrices. Therefore, the surface modification via VUV irradiation was an effective way to produce nucleation sites for calcium phosphate deposition.