Facile In-Situ Fabrication of a Ternary ZnO/TiO2/Ag Nanocomposite for Enhanced Bactericidal and Biocompatibility Properties

Phyto-fabricated ZnO nanoparticles for anticancer, photo-antimicrobial effect on carbapenem-resistant/sensitive Pseudomonas aeruginosa and removal of tetracycline

Alternanthera sessilis (AS) leaf extract was used to synthesize zinc oxide nanoparticles (ZnO NPs). Bioanalytical characterization techniques such as X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM) confirmed the formation of crystalline ZnO NPs with average sizes of 40 nm. The AS-ZnO NPs antimicrobial activity was analyzed under dark (D) and white light (WL) conditions. The improved antimicrobial activity was observed against Escherichia coli, Staphylococcus aureus and Bacillus subtilis at the minimal inhibitory concentration (MIC) of 125 and 62.5 µg/mL under WL than the D at 125 and 250 µg/mL for E. coli, B. subtilis, and Pseudomonas aeruginosa, respectively. In contrast, the growth of P. aeruginosa and S. aureus was not completely inhibited until 1 mg/mL AS-ZnO NPs under WL and D. Similarly, AS-ZnO NPs displayed a weaker inhibitory effect against carbapenem-sensitive P. aeruginosa (CSPA) and carbapenem-resistant P. aeruginosa (CRPA) strains of PAC023, PAC041 and PAC032, PAC045 under D. Interestingly, the distinct inhibitory effect was recorded against CSPA PAC041 and CRPA PAC032 in which the bacteria growth was inhibited 99.9% at 250, 500 µg/mL under WL. The cytotoxicity results suggested AS-ZnO NPs demonstrated higher toxicity to MCF-7 breast cancer cells than the RAW264.7 macrophage cells. Further, AS-ZnO NPs exhibited higher catalytic potential against tetracycline hydrochloride (TC-H) degradation at 65.6% and 60.8% under WL than the dark at 59.35% and 48.6% within 120 min. Therefore, AS-ZnO NPs can be used to design a photo-improved antimicrobial formulation and environmental catalyst for removing TC-H from wastewater.

Antimicrobial Activity of Citrate-Coated Cerium Oxide Nanoparticles

The purpose of this study was to investigate the antimicrobial activity of citrate-stabilized sols of cerium oxide nanoparticles at different concentrations via different microbiological methods and to compare the effect with the peroxidase activity of nanoceria for the subsequent development of a regeneration-stimulating medical and/or veterinary wound-healing product providing new types of antimicrobial action. The object of this study was cerium oxide nanoparticles synthesized from aqueous solutions of cerium (III) nitrate hexahydrate and citric acid (the size of the nanoparticles was 3-5 nm, and their aggregates were 60-130 nm). Nanoceria oxide sols with a wide range of concentrations (10-1-10-6 M) as well as powder (the dry substance) were used. Both bacterial and fungal strains (Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Proteus vulgaris, Candida albicans, Aspergillus brasielensis) were used for the microbiological studies. The antimicrobial activity of nanoceria was investigated across a wide range of concentrations using three methods sequentially; the antimicrobial activity was studied by examining diffusion into agar, the serial dilution method was used to detect the minimum inhibitory and bactericidal concentrations, and, finally, gas chromatography with mass-selective detection was performed to study the inhibition of E. coli's growth. To study the redox activity of different concentrations of nanocerium, we studied the intensity of chemiluminescence in the oxidation reaction of luminol in the presence of hydrogen peroxide. As a result of this study's use of the agar diffusion and serial dilution methods followed by sowing, no significant evidence of antimicrobial activity was found. At the same time, in the current study of antimicrobial activity against E. coli strains using gas chromatography with mass spectrometry, the ability of nanoceria to significantly inhibit the growth and reproduction of microorganisms after 24 h and, in particular, after 48 h of incubation at a wide range of concentrations, 10-2-10-5 M (48-95% reduction in the number of microbes with a significant dose-dependent effect) was determined as the optimum concentration. A reliable redox activity of nanoceria coated with citrate was established, increasing in proportion to the concentration, confirming the oxidative mechanism of the action of nanoceria. Thus, nanoceria have a dose-dependent bacteriostatic effect, which is most pronounced at concentrations of 10-2-10-3 M. Unlike the effects of classical antiseptics, the effect was manifested from 2 days and increased during the observation. To study the antimicrobial activity of nanomaterials, it is advisable not to use classical qualitative and semi-quantitative methods; rather, the employment of more accurate quantitative methods is advised, in particular, gas chromatography-mass spectrometry, during several days of incubation.

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.

Synthesis of Zinc Oxide (ZnO)-Titanium Dioxide (TiO2)-Chitosan-Farnesol Nanocomposites and Assessment of Their Anticancer Potential in Human Leukemic MOLT-4 Cell Line

Leukemia is the most prevalent cancer in children and one of the most common and deadly cancers that affect adults. Several metal oxide nanoparticles, biopolymers, and phytochemicals have been discovered to target cancer cells selectively while inflicting low to no damage to healthy cells. Among the existing nanoparticle synthesis methodologies, biologically synthesized nanoparticles using phytochemicals have emerged as a straightforward, economical, and environmentally sound strategy. The synergistic antitumor potential of ZnO-TiO2-chitosan-farnesol nanocomposites (NCs) against leukemia MOLT-4 cells was investigated in the current study. After synthesizing the NCs, characterization of the same was carried out using XRD, DLS, FESEM, TEM, PL, EDX, and FTIR spectroscopy. To analyze its anticancer activity, MOLT-4 cells were cultured and treated at diverse dosages of NCs. The cell viability upon treatment was examined by MTT assay. The morphological and nuclear modifications were observed by dual staining. ROS and MMP levels were observed by DCFH-DA staining and Rh-123 dye, respectively. Furthermore, the caspase 3, 8, and 9 levels were examined by performing ELISA. The XRD patterns exhibited a hexagonal structure of the NCs. In the DLS spectrum, the hydrodynamic diameter of the NCs was observed to be 126.2 nm. The electrostatic interface between the ZnO-TiO2-chitosan-farnesol NCs was confirmed by the FTIR spectra. A significant loss of cell viability in a dosage-dependent trend confirmed the cytotoxic effect of the NCs. An elevated ROS level and MMP depletion suggested apoptosis-associated cell death via the intrinsic pathway, which was confirmed by elevated expressions of caspase 3, 8, and 9 markers. Thus, the results showed that the synthesized NCs demonstrated a remarkable anticancer potential against leukemic cells and can be potentially valuable in cancer treatments. The findings from this study conclude that this is a new approach for modifying the physicochemical characteristics of ZnO-TiO2-chitosan-farnesol composites to increase their properties and synergistically exhibit anticancer properties in human leukemic cancer cells.

Multifunctional applications of natural polysaccharide starch and cellulose: An update on recent advances

The emergence of clinical complications and therapeutic challenges for treating various diseases necessitate the discovery of novel restorative functional materials. Polymer-based drug delivery systems have been extensively reported in the last two decades. Recently, there has been an increasing interest in the progression of natural biopolymers based controlled therapeutic strategies, especially in drug delivery and tissue engineering applications. However, the solubility and functionalisation due to their complex network structure and intramolecular bonding seem challenging. This review explores the current advancement and prospects of the most promising natural polymers such as cellulose, starch and their derivatives-based drug delivery vehicles like hydrogels, films and composites, in combating major ailments such as bone infections, microbial infections, and cancers. In addition, selective drug targeting using metal-drug (MD) and MD-based polymeric missiles have been exciting but challenging for its application in cancer therapeutics. Owing to high biocompatibility of starch and cellulose, these materials have been extensively evaluated in biomedical and pharmaceutical applications. This review presents a detailed impression of the current trends for the construction of biopolymer-based tissue engineering, drug/gene/protein delivery vehicles.