Genotoxicity of chitosan nanoparticles for use in food packaging films

Why it matters

According to the researchers, nanoparticles composed of different materials have been incorporated into packaging materials, where they afford greater protection to foods due to effects including reduced gas and odor permeation, blocking of ultraviolet radiation, enhanced mechanical properties and thermal stability. The considerable potential for use of these particles in the area of nanofood needs assessment of their toxicity and any possible risks they may pose to human health and the environment. Various tests have been described to measure the toxicity of nanostructured systems; amongst the most important are analyses of cellular viability employing mammalian cells, including tests based on reduction of tetrazolium salts or genotoxicity tests. The authors investigated the genotoxicity of polymeric chitosan and poly-methacrylic acid nanoparticles, having different sizes, using the Allium cepa chromosome damage test as well as cytogenetic tests employing human lymphocyte cultures, to obtain further information concerning the safety of the nanoparticles, since they have considerable potential for use in edible films for foods.

Reference

The article appears in the August 2010 issue of the Journal of Food Science (volume 75, issue 6, pages N89-N96). Authors: Renata De Lima, Leandro Feitosa, Anderson do Espírito Santo Pereira, Márcia Regina De Moura, Fauze Ahmad Aouada, Luiz Henrique Capparelli Mattoso & Leonardo Fernandes Fraceto.

Abstract

The use of nanoparticles in food packaging has been proposed on the basis that it could improve protection of foods by, for example, reducing permeation of gases, minimizing odor loss, and increasing mechanical strength and thermal stability. Consequently, the impacts of such nanoparticles on organisms and on the environment need to be investigated to ensure their safe use. In an earlier study, Moura and others (2008a) described the effect of addition of chitosan (CS) and poly(methacrylic acid) (PMAA) nanoparticles on the mechanical properties, water vapor, and oxygen permeability of hydroxypropyl methylcellulose films used in food packaging. Here, the genotoxicity of different polymeric CS/PMAA nanoparticles (size 60, 82, and 111 nm) was evaluated at different concentration levels, using the Allium cepa chromosome damage test as well as cytogenetic tests employing human lymphocyte cultures. Test substrates were exposed to solutions containing nanoparticles at polymer mass concentrations of 1.8, 18, and 180 mg/L. Results showed no evidence of DNA damage caused by the nanoparticles (no significant numerical or structural changes were observed), however the 82 and 111 nm nanoparticles reduced mitotic index values at the highest concentration tested (180 mg/L), indicating that the nanoparticles were toxic to the cells used at this concentration. In the case of the 60 nm CS/PMAA nanoparticles, no significant changes in the mitotic index were observed at the concentration levels tested, indicating that these particles were not toxic. The techniques used show promising potential for application in tests of nanoparticle safety envisaging the future use of these materials in food packaging.