Biofilm Formation on Novel Human Prosthetics Metal Alloys

Solid biomaterials with characteristics, such as high biocompatibility or corrosion resistance, are now being implanted in the human body more frequently for a wide range of purposes. However, implant-related infection is generally the most common serious complication. When bacteria adhere to and proliferate on the biomaterial surface, the bacteria produce extracellular polymeric substances, primarily polysaccharides, which mediate cell-to-cell adhesion and form a biofilm. In our lab, the long-term goal is to extend the life of a prosthetic implant by identifying new metal alloys that are less susceptible to bacterial colonization. Using two major biofilm producing bacteria commonly found to colonize implants after surgery, Staphylococcus and Pseudomonas aeruginosa, we investigated the biocompatibility of novel metal alloys with regard to their susceptibility to biofilm propagation. The Experimental biometal alloys examined were stainless steel (SS), commercially pure titanium (CPTi), titanium alloy (Ti64) and dental grade titanium (Ty). Biofilm formation was analyzed using crystal violet staining and fluorescent microscopy. Ideal experimental conditions were obtained using flasks with 50mL TSB media for 48 hours at 37oC or using a biofilm reactor with 350mL TSB media, and allowing incubation for 72 hours at 37oC. Biofilm reactor experiments were performed with or without a constant infusion of growth media during biofilm formation. Results indicate that the Ty alloy permits less biofilm formation than SS, CPTi and the Ti64, by Staphylococcus epidermidis. Thus, the Ty alloy may be a better alternative to traditional metals, stainless steel and pure titanium, as a modern prosthetic biometal.