Preparation of Silver/Chitosan Nanofluids Using Selected Plant Extracts: Characterization and Antimicrobial Studies against Gram-Positive and Gram-Negative Bacteria

Abstract

Chitosan/silver nanofluids were prepared using Phoenix dactylifera (DPLE) or Rumex vesicarius (HEL) extracts as the reducing agent, characterized using Fourier-transform infrared spectroscopy (FTIR), ultraviolet–visible (UV-vis), X-ray diffraction (XRD), and transmission electron microscope (TEM). The antimicrobial effect of the nanofluids against Gram positive, Bacillus licheniformis, Staphylococcus haemolyticus, Bacillus cereus, and Micrococcus luteus, and Gram-negative Pseudomonas aeruginosa, Pseudomonas citronellolis, and Escherichia coli bacteria has been studied. The nanoparticles were polydispersed in the chitosan matrix and are highly stable. The zeta potential of the silver nanoparticles in DPLE- and HEL-mediated composites is +46 mV and +56 mV, respectively. The FTIR results reveal that the free carboxylate groups in the plant biomaterial took part in stabilization process. HEL is a stronger reducing agent than DPLE and nanoparticles generated with HEL are smaller (8.0–36 nm) than those produced with DPLE (10–43 nm). DPLE- and HEL-mediated composites effectively inhibit the growth of the studied bacteria but HEL-mediated composite exhibited higher effect. The higher antimicrobial activity of HEL-mediated composite is linked to the smaller nanoparticles. The foregoing results indicate that HEL extract can be used in the green production of potential antimicrobial chitosan/silver nanofluids for biomedical and packaging applications.

Antimicrobial Activity of Chemically and Biologically Treated Chitosan Prepared from Black Soldier Fly (Hermetia illucens) Pupal Shell Waste

“…On the other hand, a larger diameter of inhibition of 33 mm has been reported based on their findings for S. aureus [53]. The BSF chitosan demonstrated stronger activity against P. aeruginosa and gave a diameter of inhibition of 21 mm, which was lower compared to the findings of [53,54], with diameters of 27 mm and 12 mm, respectively [53,54]. Chitosan from BSF demonstrated notable antibacterial activity against B. subtilis, which was consistent with previous studies [55].…”

Preparation of Polyurea Microcapsules by Interfacial Polymerization of Isocyanate and Chitosan Oligosaccharide

“…Some of the properties of COS differ from those of chitosan, e.g., it has good aqueous solubility. It has anti-inflammatory, anticancer, antioxidant, and antifungal properties and has been widely used in medical applications, animal feed, fertilizers, and pesticides [20][21][22][23][24][25][26][27][28][29][30][31]. In the field of crop protection, COS has been shown to change the soil flora, promote the growth of beneficial microorganisms, and induce disease resistance of plants; it can be used in biological pesticides, growth regulators, and fertilizers [20,[32][33][34][35].…”

Effect of theMelicoccus bijugatusleaf and fruit extracts and acidic solvents on the antimicrobial properties of chitosan–starch films

“…The antimicrobial activity of chitosan-starch modified films with M. bijugatus can be compared with other studies using chitosan films modified with natural extracts. Umoren et al (2020) analysed the antimicrobial characteristics of chitosan/silver nanofluids with Phoenix dactylifera (DPLE) or Rumex vesicarius (HEL) extracts against pathogenic Gram-positive (B. licheniformis, S. haemolyticus, B. cereus and M. luteus) and Gram-negative (P. aeruginosa, P. citronellolis and E. coli). The measured inhibition zone was 7Á0-11Á0 mm for DPLE-composite and 7Á5-14Á0 mm for HEL-composite, except for S. haemolyticus.…”