Physicochemical Effects of Chitosan-Tripolyphosphate Nanoparticles on Antibacterial Activity against Gram-positive and Gram-negative Bacteria

Recently, increasing attention has been focused to develop nanoparticles based on chitosan. Chitosan has been shown to exhibit a high antibacterial activity against Gram-positive and also Gram-negative bacteria. The study therefore, aims to determine antimicrobial activity of chitosan nanoparticles in vitro on S. aureus and E. coli. Nanoparticles were prepared using ionic gelation method. Antibacterial activity of these nanoparticles was then determined by measuring their Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC). MIC and MBC values were in the range of 0.24-31.25 and 1.95-125 g mL-1, respectively depending on the particle size and suspending mediums. Smaller nanoparticles (400 nm) showed higher antibacterial activity in comparison to larger ones (700 nm). Smaller particles have larger surface areas which would be in contact with the bacteria, hence gave better inhibition. In conclusion, chitosan demonstrated its antibacterial activity as nanoparticle form and the activity was mainly influenced by its particle size.