Cytotoxicity and bactericidal activity of alginate/polyethylene glycol films with zinc oxide or silicon oxide nanoparticles for food packaging

Abstract

In the food industry, packaging is used to protect food. However, traditional packaging has serious environmental impacts. Thus, studies have investigated packaging composed of biodegradable polymers. Accordingly, the present study aimed to obtain and characterize polymeric films of sodium alginate and polyethylene glycol crosslinked with tetraethoxysilane and doped with nano-zinc oxide or nano-silicon oxide and evaluate their cytotoxicity and bactericidal activity against coliforms and Escherichia coli. The nanoparticles and crosslinked materials were characterized using infrared and Raman spectroscopy. The cytotoxicity of the films was evaluated using a direct contact assay with a bovine fibroblast cell model. The bactericidal activity of the films was assessed by determining whether the contamination indicators were activated. The average sizes of the ZnO and SiO2 nanoparticles were 408.3 and 125.3 nm, respectively, and their zeta potentials were −31.6 and −31.1 mV, respectively. Cell growth inhibition zone tests indicated that 75 ALG/25 PEG/SiO2 was slightly toxic, while 25 ALG/75 PEG/ZnO exhibited mild toxicity. Cell area analysis showed that the addition of SiO2 decreased the cytotoxicity of the obtained films. Finally, it was possible to observe the inactivation of both contamination bioindicators. Therefore, films containing nanoparticles could be promising biomaterials for packaging in the food industry.