Application of the response surface methodology for the evaluation of Staphylococcus aureus inhibition with Ag/TiO2 nanoparticles

The present work shows the implementation of response surface methodology, fed by an experimental central composite design (CCD) to find conditions that allow maximizing inhibition microorganism Staphylococcus aureus with nanoparticles TiO2 silanized 3-aminopropyltriethoxysilane (APTES) and doped Ag. In addition, poly(lactic) acid composites were prepared these Ag/TiO2 aim confer their antimicrobial effect. independent variables considered pH, AgNO3/TiO2 ratio (% w/w), concentration (g/250 mL), as variable response, length diameter halo or zone presented (mm). Statistical analysis found maximization S. occurs at intermediate levels a value 10 for pH 5 g solids, while AgNO3 high are required, greater than 10% w/w. Likewise, statistical significance was determined using Student's t test p value; it significant effect corresponds AgNO3, so second CCD equiradial two factors considered, estimating amount, constant value. indicated in between 20 25% w/w amounts solids (7–8 g), resulting 26 28 mm. quadratic model obtained, which represents relationship lengths adjustment data coefficient determination (R2) 0.82.