In a recent article published in Scientific Reports, researchers from Iran presented an approach to optimize antimicrobial nanocomposite films by studying the effects of varying concentrations of carboxymethyl cellulose, Commiphora mukul polysaccharide, and Chitosan Nanofiber on film properties. Due to their antimicrobial properties, these films have potential applications in food packaging and biomedical fields.
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Background
Antimicrobial nanocomposite films have garnered significant interest for their applications in food packaging and biomedical fields. These films can combat microbial infection and extend the shelf lives of perishable products by incorporating antimicrobial elements into a polymeric matrix. This effectively inhibits the growth of microorganisms and fungi, enhancing the protection and satisfaction index of packaged goods.
Carboxymethyl cellulose (CMC) is a widely used biopolymer known for its film-forming abilities and biodegradability, making it an appealing candidate for the development of sustainable packaging materials. The addition of functional components, together with Commiphora mukul polysaccharide (CMP) and Chitosan Nanofiber (CHNF), can further intensify the antimicrobial efficacy and mechanical strength of CMC-primarily based films.
The Current Study
The antimicrobial nanocomposite films were prepared by blending CMC, CMP, and CHNF using an answer-casting technique. Initially, CMC was dissolved in distilled water with constant stirring to achieve a homogeneous solution. Predetermined quantities of CMP and CHNF were introduced to the CMC solution and stirred vigorously to ensure uniform dispersion of the components.
The film casting method involved pouring the mixed answer onto clean glass plates and spreading it using a film applicator to achieve uniform film thickness. After drying, the films were carefully peeled from the glass plates and stored in a desiccator to enhance moisture absorption.
A central composite design (CCD) within the framework of the response surface methodology (RSM) was used to optimize the concentrations of CMC, CMP, and CHNF in the nanocomposite films. The design matrix included a set of experimental runs with varying levels of independent variables based on coded values.
Responses such as ultimate tensile strength (UTS), stress at break (SAB), water vapor permeability (WVP), solubility, swelling, moisture content, opacity, and total color difference were measured for each experimental run.
The physical and antimicrobial properties of the nanocomposite films were evaluated using standard characterization techniques. Ultimate tensile strength and stress at break were determined using a universal testing machine.
Water vapor permeability was measured using permeability testing equipment. The material's solubility, swelling, and moisture content were assessed following installed protocols. Opacity and general coloration distinction were analyzed using a spectrophotometer.
The antimicrobial activity of the nanocomposite films was assessed in its activity towards foodborne pathogens and yeast traces, which included Staphylococcus aureus, Salmonella enterica, Escherichia coli, and Saccharomyces cerevisiae. The significance of the individual coefficients was assessed using analysis of variance (ANOVA) at a confidence level of 95 %. The models were tested by evaluating the expected values with the experimental information.
Results and Discussion
The study centered on numerous responses, including UTS, SAB, WVP, solubility, swelling, moisture content, opacity, and total color difference (ΔE).
Experimental results indicated that CMP and CHNF concentrations significantly affected the film properties. Higher concentrations of CMP and CHNF reduced moisture content and WVP while enhancing the strength of the films. However, their effects on SAB, ΔE, and swelling were complex, with varying outcomes at higher concentrations.
Incorporating CMP increased the opacity and solubility of the films, whereas CHNF addition decreased opacity and solubility. Notably, only CHNF addition enhanced the antibacterial properties of the films, as evidenced by inhibitory zones against Staphylococcus aureus, Salmonella enterica, Escherichia coli, and Saccharomyces cerevisiae.
Using RSM allowed for optimizing film properties by exploring the interactions among CMC, CMP, and CHNF concentrations. Statistical analysis revealed the significance of the models developed for each response variable, highlighting the robustness of the optimization process.
The findings emphasize the importance of carefully selecting additive concentrations to achieve desired film properties. The optimized formulation containing CMC (1.5 wt%), CMP (0.25 wt%), and CHNF (0.75 wt%) demonstrated superior physical, mechanical, and antibacterial properties in the biodegradable film matrix. This optimized formulation represents a promising advancement in the development of antimicrobial nanocomposite films with enhanced performance characteristics.
Conclusion
The research successfully optimized antimicrobial nanocomposite films by carefully selecting concentrations of carboxymethyl cellulose, Commiphora mukul polysaccharide, and Chitosan Nanofiber.
The study demonstrated the importance of utilizing RSM and appropriate modeling techniques to enhance film properties, providing valuable insights for developing antimicrobial films with potential applications in various industries.
Journal Reference
Mohammadi, H., et al. (2024). Optimization of antimicrobial nanocomposite films based on carboxymethyl cellulose incorporating chitosan nanofibers and Guggul gum polysaccharide. Scientific Reports. doi.org/10.1038/s41598-024-64528-0