Fabrication and characterization of nano-composite scaffold of PLLA/silane modified hydroxyapatite

Abstract 

In order to improve the interfacial connection of hydroxyapatite (HAP) to poly-l-lactic acid (PLLA), γ-methacryloxypropyl-trimethoxysilane (γ-MPS) was used as a coupling agent to modify the surface of nano-HAP (NHAP) particles. The FTIR and XPS results showed γ-MPS was successfully bonded on the surface of NHAP. Silane modified nano-HAP (MNHAP) and PLLA were fabricated to nano-composite scaffold by a thermally induced phase separation method. The characterization of the composite scaffold showed that the scaffold had a nano-fibrous PLLA network (fiber size 100–800nm), an interconnective microporous structure (1–8μm) and high porosity (>90%). MNHAP was homogeneously distributed in the scaffold, also partly set in the nano-PLLA fibers. As a result, the compressive modulus and the protein adsorption of PLLA/MNHAP (80:20, w/w) composite scaffold increased to 4.2-fold and 2.8-fold compared with those of a pure PLLA scaffold. Incorporating MNHAP into PLLA network also buffered the pH reduction and reduced the weight loss in vitro degradation significantly.

Keywords: Poly-l-lactic acid, Hydroxyapatite, Nano-composite, Scaffold, Silane