GS/DBM/PLA porous composite biomaterial for the treatment of infective femoral condyle defect in rats

Abstract

A bone defect resulting from open bone trauma may easily become infected; however, the administration of efficacious systemic antibiotics cannot be performed at safe levels. Previous studies have investigated anti-infective biomaterials that incorporate into bone and facilitate the direct application of high-concentration local antibiotics. In the present study, the effect of a novel porous composite with gentamicin sulfate (GS) in treating infected femoral condyle defects was investigated using a rat model. A novel porous composite biomaterial was prepared based on a supercritical carbon dioxide fluid technique that combined GS, demineralized bone matrix (DBM) and polylactic acid (PLA). A rat femoral condyle fracture model of infection was established. The GS/DBM/PLA composite biomaterial was implanted and its physicochemical characteristics, biocompatibility and ability to facilitate repair of infected bone defect were assessed. The GS/DBM/PLA composite biomaterial maintained the antibiotic activity of GS, with good anti-compression strength, porosity and biocompatibility. The results of the animal experiments indicated that the GS/DBM/PLA composite biomaterial exerted marked anti-infective effects and facilitated bone defect repair, while simultaneously controlling infection. Porous GS/DBM/PLA is therefore a promising composite biomaterial for use in bone tissue engineering.

Keywords: bone defect; bone tissue engineering; composite biomaterial; infection.

Figure 1:

Images of GS/DBM/PLA composite biomaterial obtained using (A,B) optical microscopy and (C) scanning electron microscopy, identifying pores between 200–400 µm and (D) 20–30 µm. GS, gentamicin sulfate; DBM, demineralized bone matrix; PLA, polylactic acid.

Figure 2.

Release curve of GS/DBM/PLA in vitro.

Figure 3.

Release curve of GS/DBM/PLA in vivo.

Figure 4.

Infection modeling and composite biomaterial implants in a rat model with femoral condyle fracture deficiencies. Images show the (A) exposure of the femoral condyle fracture during surgery, (B) dental drill removing the deficiencies, (C) addition of Staphylococcus aureus solution to the wound and (D) implantation of the composite biomaterial.

Figure 5.

X-ray radiographs of the implanted biomaterial for the (A) non-operated control, (B) GS/DBM/PLA and (C) DBM/PLA group. (a) 4 weeks, (b) 6 weeks and (C) 8 weeks after surgery. GS, gentamicin sulfate; DBM, demineralized bone matrix; PLA, polylactic acid.

Figure 6.

Histological images, stained with hematoxylin and eosin, of biomaterial implanting (A) after 4 weeks, displaying a small area of inflammatory tissue among the implanted biomaterial, (B) after 6 weeks, displaying mesenchymal cells growing into the implanted bone with a number of inflammatory cells, multinucleated cells around the demineralized bone matrix and osteoblasts in the lacuna, and (C) after 8 weeks, when the implanting area was fully covered with new-borne bone tissue, showing complete dissipation of inflammation (magnification, ×100).