Thermoresponsive elastin/laminin mimicking artificial protein for modifying PLLA scaffolds in nerve regeneration

Poly(l-lactic acid) (PLLA) is widely used as a scaffold but does not possess biological functions. Here, we described the biosynthesis of the elastin-like repetitive polypeptide (VPGIG)₃₀ containing a laminin-derived neurite outgrowth-promoting sequence (RKRLQVQLSIRT: AG73) (AG73-(VPGIG)₃₀). The expression vector for AG73-(VPGIG)₃₀ was constructed using the self-ligation technique to elongate the VPGIG repetitive sequence. The coacervation temperature of the purified AG73-(VPGIG)₃₀ protein was 20 and 14 °C in water and phosphate-buffered saline (PBS), respectively. AG73-(VPGIG)₃₀ was quickly adsorbed on PLLA films via a hydrophobic interaction by raising the temperature from 4 °C to 37 °C. On the AG73-(VPGIG)₃₀-modified PLLA surface, the neurite outgrowth of PC12 cells was strongly promoted. We successfully induced the neurite outgrowth activity on PLLA films by treating the novel surface modifier AG73-(VPGIG)₃₀, which could be applicable in developing PLLA scaffolds for nerve regeneration.