Silver Nanoparticle-Loaded Gelatin-Based Nanocomposite Films toward Enhanced Mechanical Properties and Antibacterial Activity

Engineering eco-friendly and biodegradable biomass-based multifunctional antibacterial packaging films for sustainable food preservation

The study presents a new class of eco-friendly and biodegradable biomass-based multifunctional antibacterial packaging films (G-OCSI) based on oxidized corn starch-based nonionic biopolymer (OCSI) and gelatin (Gel), and investigates the effects of different OCSI contents on the properties of G-OCSI. The results demonstrated that G-OCSI 0.25 had good water vapor barrier properties, antioxidant activity (DPPH RSA: 85.84 %), UV resistance (UV blocking > 99.9 %), water resistance (WCA: 122.30°), and tensile properties. Based on the disk diffusion experiment, G-OCSI exhibited significant bactericidal and antibacterial effects against S. aureus and E. coli. Moreover, G-OCSI had good biodegradability in natural environments, and could obviously accelerate the crops growth. Finally, a banana preservation experiment confirmed that G-OCSI could significantly extend the shelf life of bananas at room temperature at least 3 days. The biodegradable packaging films not only realizes the sustainable utilization of biomass resources but also has the potential to replace traditional petroleum-based plastics.

Structural Evolution of Palygorskite as the Nanocarrier of Silver Nanoparticles for Improving Antibacterial Activity

The carrier performance of palygorskite (Pal) can be significantly affected by its structure, morphology, and activity, which was regulated by controlling the dissolution degree of the metal-oxygen octahedron of raw Pal (RPal) under the action of oxalic acid (OA) in this study. The RPal and OA-leached RPal (OPal) then served as supports for immobilizing silver nanoparticles (AgNPs) to form RPal/AgNPs and OPal/AgNPs antibacterial nanocomposites. The structural and morphological characterizations were used to confirm the dispersion uniformity of AgNPs on the RPal and OPal nanorods, and antibacterial experiments were conducted to evaluate the performance of as-prepared composites and also investigate their antibacterial mechanism. The results showed that OPal-48h (OA leaching for 48 h) loaded with AgNPs (OPal-48h/AgNPs) possesses the most excellent and broad-spectrum antibacterial properties, where its minimum inhibitory concentration values against E. coli, S. aureus, ESBL-E. coli, and MRSA reached 0.25, 0.125, 0.25, and 0.5 mg/mL, respectively, which are mainly attributed to the optimal balance between surface activity and structural stability of OPal-48h that maximally increased its dispersibility and active sites, therefore contributing to the in situ formation of monodisperse AgNPs on the nanorods of OPal-48h.