Poly(lactic-co-glycolic acid)-bioactive glass composites as nanoporous scaffolds for bone tissue engineering: In vitro and in vivo studies

Abstract

The aim of the present study was to investigate the feasibility of using composite scaffolds of poly(lactic-co-glycolic acid) (PLGA) and bioactive glass (BG) to repair bone defects. PLGA/BG composite scaffolds were prepared by thermally-induced phase separation. Scanning electron microscopy (SEM) was used to study the morphology, and liquid (absolute ethanol) replacement was used to calculate the porosity of the scaffold. The biocompatibility and degradation of the scaffold were determined using human osteosarcoma cell line MG-63 and animal experiments. SEM showed that the scaffold had a nanofibrous three-dimensional network structure with a fiber diameter of 160-320 nm, a pore size of 1-7 µm, and a porosity of 93.048±0.121%. The scaffold structure was conducive to cell adhesion and proliferation. It promoted cell osteogenesis and could be stably degraded in vivo.

Keywords: bioactive glass; bone tissue engineering; poly(lactic-co-glycolic acid); scaffold.

Figure 1.

Representative SEM images of a scaffold (magnification, ×8,000). (A) SEM image of the PLGA scaffold. (B) SEM image of the PLGA/BG composite scaffold. BG, bioactive glass; PLGA, poly(lactic co-glycolic acid); SEM, scanning electron microscopy.

Figure 2.

Comparison of porosity between PLGA only scaffolds and PLGA/BG scaffolds. BG, bioactive glass; PLGA, poly(lactic co-glycolic acid).

Figure 3.

Comparison of ALP activity of MG-63 cells in two groups. *P<0.01. ALP, alkaline phosphatase; BG, bioactive glass; PLGA, poly (lactic co-glycolic acid).

Figure 4.

SEM images of MG-63 cells in the PLGA/BG scaffold. SEM image of MG-63 cells in PLGA/BG scaffold on the 3rd day at (A) ×200 and (B) ×800. SEM image of MG-63 cells in PLGA/BG scaffold on the 7th day at (C) ×750 and (D) ×1500. Arrows indicate calcified nodules. BG, bioactive glass; PLGA, poly(lactic co-glycolic acid); SEM, scanning electron microscopy.

Figure 5.

H&E staining of the graft area. H&E staining of the PLGA/BG scaffold graft area 2 weeks post-transplant at (A) ×40 and (B) ×400. H&E staining of the PLGA/BG scaffold graft area at 3 months post-transplantation at (C) ×40 and (D) ×400. H&E staining of the PLGA/BG scaffold graft area at 6 months post-transplantation, at (E) ×40 and (F) ×400. Arrows indicate the scaffold. BG, bioactive glass; PLGA, poly(lactic co-glycolic acid); H&E, hematoxylin and eosin.

Figure 6.

Sirius red staining of the PLGA/BG scaffold graft area. (A) Sirius red staining of the PLGA/BG scaffold graft 2 weeks post-transplant. (B) Sirius red staining of the PLGA/BG scaffold graft area at 3 months post-transplant. (C) Sirius red staining of the PLGA/BG scaffold graft area at 6 months post-transplant. PLGA, poly(lactic co-glycolic acid); BG, bioactive glass.