Immobilization of ZnO-TiO2 Nanocomposite into Polyimidazolium Amphiphilic Chitosan Film, Targeting Improving Its Antimicrobial and Antibiofilm Applications.

This study presents a green protocol for the fabrication of a multifunctional smart nanobiocomposite (NBC) (ZnO-PIACSB-TiO2) for secure antimicrobial and antibiofilm applications. First, shrimp shells were upgraded to a polyimidazolium amphiphilic chitosan Schiff base (PIACSB) through a series of physicochemical processes. After that, the PIACSB was used as an encapsulating and coating agent to manufacture a hybrid NBC in situ by co-encapsulating ZnONPs and TiO2NPs. The physicochemical and visual characteristics of the new NBC were investigated by spectral, microscopic, electrical, and thermal methods. The antimicrobial indices revealed that the newly synthesized, PIACSB-coated TiO2-ZnO nanocomposite is an exciting antibiotic due to its amazing antimicrobial activity (MIC/MBC→0.34/0.68 µg/mL, 0.20/0.40 µg/mL, and 0.15/0.30 µg/mL working against S. aureus, E. coli, and P. aeruginosa, respectively) and antifungal capabilities. Additionally, ZnO-PIACSB-TiO2 is a potential fighter of bacterial biofilms, with the results being superior to those of the positive control (Cipro), which worked against S. aureus (only 8.7% ± 1.9 biofilm growth), E. coli (only 1.4% ± 1.1 biofilm growth), and P. aeruginosa (only 0.85% ± 1.3 biofilm growth). Meanwhile, the NBC exhibits excellent biocompatibility, as evidenced by its IC50 values against both L929 and HSF (135 and 143 µg/mL), which are significantly higher than those of the MIC doses (0.24-24.85 µg/mL) that work against all tested microbes, as well as the uncoated nanocomposite (IC50 = 19.36 ± 2.04 and 23.48 ± 1.56 µg/mL). These findings imply that the new PIACSB-coated nanocomposite film may offer promising multifunctional food packaging additives to address the customer demand for safe, eco-friendly food products with outstanding antimicrobial and antibiofilm capabilities.

Development of Mechanically Reliable and Transparent Photochromic Film Using Solution Blowing Spinning Technology for Anti-Counterfeiting Applications.

Photochromic materials have attracted broad interest to enhance the anti-counterfeiting of commercial products. In order to develop anti-counterfeiting mechanically reliable composite materials, it is urgent to improve the engineering process of both the material and matrix. Herein, we report on the development of anti-counterfeiting mechanically reliable nanocomposites composed of rare-earth doped aluminate strontium oxide phosphor (RESA) nanoparticles (NPs) immobilized into the thermoplastic polyurethane-based nanofibrous film successfully fabricated via the simple solution blowing spinning technology. The generated photochromic film exhibits an ultraviolet-stimulated anti-counterfeiting property. Different films of different emissive properties were generated using different total contents of RESA. Transmission electron microscopy was utilized to investigate the morphological properties of RESA NPs to display a particle diameter of 3-17 nm. The morphologies, compositions, optical transmittance, and mechanical performance of the produced photochromic nanofibrous films were investigated. Several analytical methods were employed, including energy-dispersive X-ray spectroscopy, scanning electron microscopy, and Fourier-transform infrared spectrometry. The fibrous diameter of RESA-TPU was in the range of 200-250 nm. In order to ensure the development of transparent RESA-TPU film, RESA must be prepared in the nanosized form to allow better dispersion without agglomeration in the TPU matrix. The luminescent RESA-TPU film displayed an absorbance intensity at 367 nm and two emission intensities at 431 and 517 nm. The generated RESA-TPU films showed an enhanced hydrophobicity without negatively influencing their original appearance and mechanical properties. Upon irradiation with ultraviolet light, the transparent nanofibrous films displayed rapid and reversible photochromism to greenish-yellow without fatigue. The produced anti-counterfeiting films demonstrated stretchable, flexible, and translucent properties. As a simple sort of anti-counterfeiting substrates, the current novel photochromic film provides excellent anti-counterfeiting strength at low-cost as an efficient method to develop versatile materials with high mechanical strength to create an excellent market as well as adding economic and social values.