Novel silicon dioxide based nanocomposites as an antimicrobial in poly (lactic acid) nanocomposites films

Objective(s): Due to nanocomposites antimicrobial properties, one of the most extensive usages of nano-products is in packing industry. Thus, the production of packages with nanotechnology can effectively prevent against a variety of micro- organisms. In this study, the silicon dioxide nanoparticles the poly (lactic acid) PLA films on antimicrobial and permeability was investigated. Methods: In order to measure the effect of antibacterial nano-covers, the direct contact of 1%, 3% and 5% silicon dioxide nanoparticles was used. Furthermore, the sample was contaminated with standard strains of gram-negative (Escherich- ia coli –code of 1399 (ATCC 25992)) and bacteria gram-positive (Staphylococcus aureus–code of 1431 (ATCC 25923)) provided. Diameters of inhibition zones were measured after 24 h incubation of plates at 37 °C, by using Digital Caliper. Also, the water vapor permeability was investigated according to ASTM E96 and oxygen standards according to ASTM D 3985 standard from film surface. Results: Comparison the mean diameter of the inhibition zone of Escherichia coli, PLA containing 3% silicon dioxide with PLA film containing 5% silica showed no significant difference between the two groups (P 0.05) as well as, the average diameter of Staphylococcus aureus (P 0.05). The results showed that the perme- ability compared to water vapor and oxygen vapor in pure PLA films with PLA con- taining 1%, 3% and 5% silicon dioxide showed a significant difference (P 0.05). Conclusion: PLA /nanocomposite SiO2 films have been identified as the most effi- cient cover in reducing the microbial load and have been useful as active antimi- crobial nanopackaging.