Development of (polyvinylpyrrolidone/chitsoan/citric acid)/(zinc oxide-nanoparticles) bionanocomposite films and their applications in biodegradation and antimicrobial activity

Biofilm and bionanocomposite films were synthesized from polyvinylpyrrolidone (PVP), chitosan (CS), citric acid (CA), and zinc oxide-nanoparticles (ZnO-NPs). Effects of gamma-irradiation dose and ZnO-NPs concentrations; 0, 0.1, 0.3, 0.6, 0.9, 1.2, and 1.5 (wt./wt.)% were studied. Biofilms and bionanocomposite films were characterized by Fourier transform infrared, Raman spectroscopy, transmission electron microscopy, thermal gravimetric analysis, X-rays diffraction, energy dispersive X-ray, and mechanical properties to identify structure of biofilm and bionanocomposite films. Swelling (g/g)% and gelation (g/g)% of biofilms were carried out at diverse compositions of PVP to CS of (1/1), (1/2), and (2/1) (v/v). Swelling (g/g)% results of (1/1), (1/2), and (2/1) (v/v) were 116, 110, and 126, respectively. Values of highest and lowest gelation (g/g)% of (1/2) and (2/1) (v/v) are 98.0 +/- 1.8 and 85.0 +/- 2.6, respectively at 30 kGy. Water vapor transmission rate was studied for films and exposed 3450 +/- 4.1 and 185.8 +/- 1.2 (kg/m(2).day) for open bottle and (PVP/CS/PCA)/(ZnO-NPs-1.5), respectively. Values of water solubility (g/g)% were investigated and found 30.21 +/- 1.3 and 15.4 +/- 2.5 for (PVP/CS/PCA)/(ZnO-NPs-0) and (PVP/CS/PCA)/(ZnO-NPs-1.5), accordingly. Bionanocomposite films displayed a broad-spectrum antimicrobial activity against Gram-negative bacteria and Gram-positive bacteria. (PVP/CS/PCA)/(ZnO-NPs-0.1) showed lowest inhibition zone; 4 +/- 0.2, 9 +/- 0.5, 19 +/- 0.1, and 8 +/- 0.3 (mm) compared with (PVP/CS/PCA)/(ZnO-NPs-1.5) of highest inhibition zone; 16 +/- 0.5, 28 +/- 0.2, 33 +/- 0.6, and 18 +/- 0.3 (mm) for Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus, respectively. Antimicrobial activity increased with increasing ZnO-NPs concentrations. Biodegradation of biofilms and bionanocomposite films were examined under soil from 0 to120 days. Results of weight loss (g/g)% at 120 days of (PVP/CS/PCA)/(ZnO-NPs-0) and (PVP/CS/PCA)/(ZnO-NPs-1.5) are 72 +/- 4.5 and 47.5 +/- 3.8, respectively. Bionanocomposite films were used in food preservation of fresh cherry tomatoes for 30 days and showed goodness. Therefore, these results suggest that the possibility of using bionanocomposite films in food-packaging applications.

Automated summary

Biofilm and bionanocomposite films were synthesized using polyvinylpyrrolidone, chitosan, citric acid, and zinc oxide nanoparticles. The films displayed antimicrobial and biodegradable properties, making them suitable for food packaging applications.