Effect of changing coating process parameters in the preparation of antimicrobial-coated silk sutures: An in vitro study

Abstract

Braided silk sutures were coated using a combination of poly(ε-caprolactone) (PCL) and sulfamethoxazole trimethroprim (SMZ) to investigate their antimicrobial performance. SMZ (2500 μg/ml) was combined with different PCL concentrations, i.e., 2.5 %, 5 %, 7.5 %, and 10 % (w/v). Antimicrobial test results showed that SMZ and PCL-treated silk sutures exhibited increasing antimicrobial efficacy against Gram-negative (Escherichia coli) and -positive bacteria (Staphylococcus aureus) with increasing PCL concentrations. The tensile and knot strength of sutures coated with 10 % PCL were significantly higher than those of sutures coated with 7.5 %, 5 %, and 2.5 % PCL. Treatment with PCL exhibited a positive effect on drug release from the sutures. Significant traits of antibacterial activity were observed up to 4 days after instalment of 10 % PCL-coated silk sutures. Under a scanning electron microscope, untreated silk sutures showed a surface heavily coated with bacteria, whereas treated sutures showed a smooth surface without bacteria. The results of this study indicate that SMZ combined with high concentrations of PCL may afford a suitable antibacterial coating agent for braided silk sutures.