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Cadmium-tolerant (6 mM) Aspergillus niger (RCMB 002002) biomass was challenged with aqueous cadmium chloride (1 mM) followed by sodium sulfide (9 mM) at 37°C for 96 h under shaking conditions (200 rpm), resulting in the formation of highly stable polydispersed cadmium sulfide nanoparticles (CdSNPs). Scanning electron microscopy revealed the presence of spherical particles measuring approximately 5 nm. A light scattering detector (LSD) showed that 100% of the CSNPs measure from 2.7 to 7.5 nm. Structural analyses by both powder X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) confirmed the presence of cubic CdS nanoparticles (CdSNPs) capped with fungal proteins. These CdSNPs showed emission spectra with a broad fluorescence peak at 420 nm and UV absorption onset at 430 nm that shifted to 445 nm after three months of incubation. The CdSNPs showed antimicrobial activity against E. coli, Pseudomonas vulgaris, Staphylococcus aureus, and Bacillus subtilis, and no antimicrobial activity was detected against Candida albicans. The biosynthesized CdSNPs have cytotoxic activity, with 50% inhibitory concentrations (IC50) of 190 μg mL-1 against MCF7, 246 μg mL-1 against PC3, and 149 μg mL-1 against A549 cell lines.

Here we report the phycosynthesis of silver nanoparticles (Ag-NPs), using Codium capitatum extract, and the synthesis of fungal chitosan nanoparticles (FC-NPs), using extracted chitosan from Aspergillus niger mycelia. Then nanoconjugates from FC/Ag-NPs were produced and evaluated. The synthesized NPs had mean particles' size diameters of 37.2, 68.4 and 79.6 nm for Ag-NPs, FC-NPs and FC/Ag-NPs, respectively. The FTIR (Fourier-transform infrared spectroscopy) analysis of synthesized NPs indicated their cross-linkage and interaction. The antibacterial activity of each type of NPs was assayed against drug resistant pathogens of Salmonella Typhimurium and Staphylococcus aureus. All NPs had powerful inhibitory effect and FC/Ag nanoconjugates had stronger activity than the other types. Scanning micrographs of FC/Ag-NPs treated S. Typhimurium elucidated vigorous alterations in cell surfaces and lethal damage to bacterial structure after 8 h of treatment. The nanoconjugates form FC-NPs and Ag-NPs had minute particle size with increasing bioactivity as antimicrobial agents to control drug resistant bacterial pathogens, which recommends their further exploration for topical applications in biomedical sectors.

Shrimps are highly valuable and perishable foodstuff that could be rapidly spoiled. Chitosan (Cht) was extracted and transformed into nanoparticles (NPs) via ionic gelation and fortified with cloves (Syzygium aromaticum) buds extract (CLE) for usage as antimicrobial composites against food-borne bacterial pathogens (Escherichia coli, Salmonella typhimurium, and Staphylococcus aureus) and as edible coating (EC) for shrimp (Fenneropenaeus indicus) biopreservation throughout refrigerated storage. The synthesized CLE/Cht-NPs were electrostatically cross-linked and appeared with spherical shapes and homogenized distribution, with 159.4 nm mean size diameter and positive charge of 17.4 mV. The entire agents (Cht-NPs, CLE, and CLE/Cht-NPs) exhibited remarkable antibacterial activities toward all food-borne pathogens; CLE/Cht-NPs were significantly the most forceful. The scanning micrographs of treated S. typhimurium with CLE/Cht-NPs displayed NPs ability to attach and destroy bacterial cells. The ECs-treated shrimps exhibited sharp decrease in microbial groups load (aerobic microorganisms, E. coli, Enterobacteriaceae, and staphylococci) during refrigerated storage (4 ± 1°C) for 10 days. Additionally, the sensorial attributes (appearance, odor, color, and texture) of EC-treated samples preserved their elevated qualities for storage duration. The most effective EC blend contained 1.5% from Cht/NPs and 1.0% from CLE. The CLE/Cht-NPs could be impressively recommended as effectual natural composites for shrimps’ biopreservation during cold storage.

Skin wounds are frequently influenced with microbial infections and inflammation, which need innovative agents for disputing them. Chitosan (Csn) was extracted from larvae of BSF “black soldier fly, Hermetia illucens” and ethanolic propolis extract (Pro) was employed for synthesizing silver nanoparticles (Ag-NPs), using facile biogenic protocol. The BSF-Csn was acquired with a yield of 1.56%, 91.3% deacetylation degree, and 88.600 Dalton molecular weight. The Ag-NPs were effectually biosynthesized using Pro, with a mean diameter of 8.73 nm and zeta potential of -21.34 mV. The antimicrobial activities assessment of insect Csn, Pro, synthesized Ag-NPs with Pro, and their composite against skin pathogens (Staphylococcus aureus and Candida albicans) revealed the elevated efficiency of the individual agents and the superior action of their composite (Csn/Pro/Ag-NPs), with 26.3 and 23.4 mm inhibition zones and inhibitory concentrations of 35.0 and 45.0 μg/mL from the composite toward S. aureus and C. albicans, respectively, which exceeded the actions of commercial antibiotics. The treatment of rat’s wounds with this composite promisingly led to faster healing of wounds and absence of inflammation and infection signs. The powerful actions of Csn/Pro/Ag-NPs as antimicrobial and wound healing composite strongly advocate their applications for skin protection, disinfection, and regeneration.

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Selenium (Se) as a bioactive micronutrient could be augmented via transforming into nanoparticles (NPs), especially using biogenic protocols, for usage as an antimicrobial element. The reducing power of costus (Saussurea costus) root extract (SCE) was employed for phytosynthesis of Se-NPs through a simple and rapid protocol that included stirred mixing of 10 mM Na2SeO3 with 1.0% SCE solution for 4 h. The phytosynthesized SCE/Se-NP composite was obtained with a mean diameter of 6.13 nm and a zeta potential of −42.8 mV. Infrared analyses revealed the involvement of many SCE phytogroups in Se-NP synthesis, whereas transmission microscopy displayed well distribution and spherical shapes of the phytosynthesized NPs. The antibacterial assessments against foodborne pathogens (Escherichia coli, Salmonella typhimurium and Staphylococcus aureus) revealed the superior powers of SCE/Se-NPs and the elevated potentialities of SCE and Se-NPs for inhibition of bacterial pathogens. The scanning micrographs indicated that SCE/Se-NPs were attached to bacterial cells and led to their complete lysis/explosion with exposure prolongation. The SCE/Se-NP composites are recommended for the effective control of foodborne bacterial pathogens, applying a simple and eco-friendly phytosynthesis protocol.

Skin is the largest protective organ that could be recurrently wounded and attacked by microorganisms. The wounded skin safeguarding and supporting were intended through natural derivatives. Fish collagen (Cg) type I, extracted from sea bream (Spondyliosoma cantharus), chitosan nanoparticles (NCht) from shrimp shells, and henna (Lawsonia inermis L.) leaves extract (He) were produced and physiochemically characterized. The antimicrobial potentialities of these compounds and their composites were assessed toward skin pathogens (Candida albicans and Staphylococcus aureus) using various assaying methods and microimaging techniques. The infrared and electrophoretic analysis of Cg validated its characteristics, and the IR-spectroscopic analysis of the compounds/composites indicated their physiochemical attributes and interrelations. The produced NCht particles had a diameter range of 64.6-308.8 nm, 104 nm mean diameter, and +31.3 mV zeta potentiality. Both NCht, He, and NCht/He composite exhibited significant antimicrobial potentiality toward skin pathogens; NCht/He was the strongest with inhibitory concentrations of 20.0 and 22.5 μg/mL and inhibition zones of 25.7 and 26.8 mm against S. aureus and C. albicans, respectively. The electron micrographs verified the synergistic microbicidal action of NCht/He, as they led to severe microbial lysis and deformations. The skin wounds’ treatment with NCht/He/Cg composite promoted the fastest and complete healing of wounded rats’ skin during 8 days of local treatment, with the absence of inflammation and infection signs; treated with NCht/He/Cg composite, the wound area vastly reduced from 63.6 mm2 to 15.9 and 9.1 mm2 after 2 and 4 days, respectively. The natural NCht/He/Cg composites are recommended as topical applications for optimum skin disinfection and regeneration.