Development of soft tissue regenerative scaffold with antibacterial activity

With increasingly aging and sedentary populations, and with the rising incidence of diabetes and the associated diabetic ulcers, chronic wounds have been reported to be approaching pandemic proportions. Accumulation of wound bacteria forms a biofilm that can inhibit wound healing and the action of antibiotics. Conventional skin grafts can readily harbor bacterial and fungal cells while excluding penetration of larger immune cells and essential neo-vascularization. Soft tissue regenerative scaffolds with highly interconnected porosity have been developed for wound healing. In this research, scaffolds were fabricated with bioactive components to impart antibacterial activity. The interconnective porosity of the scaffold was preserved through using thermally forming composite scaffolds. Bioactive glass (45S5), bulk metallic glass (MgZnCa), and infused antibiotic (Cephazolin sodium) were utilised to form the composite antibiotic eluting scaffolds. A novel in vivo wound model was generated to simulate the wound environment. A confluent biofilm of Staphylococcus aureus was generated on polymer coupons using a bioreactor. The coupons were placed within nutrient agar dishes (simulating tissue) underneath scaffold specimens. Gravity fed perfusion flow was set up using a drip-set kit.The model successfully replicated the planktonic phase of the Staph. aureus life-cycle and infection of the scaffold from the wound model. Bioactive glass by itself did not contribute any detectable Staph.antibacterial activity whether on the scaffold or fused to a silicone substrate. However, when bioactive glass was present with MgZnCa and antibiotic, a mild synergistic improvement in antibacterial activity was observed. This strategy may facilitate soft tissue adhesion and further militate against bacterial infection. This study is the first report of an in-vitro wound model with an infusion method and planktonic bacteria phase, applied to assess antibacterial synthetic scaffold