Radiation-induced synthesis of colloidal silver nanoparticles (Ag-NPs) using chitosan (CTS) as a stabiliser and free radical scavenger is feasible and satisfiable to green method. The conversion dose (Ag⁺ into Ag⁰) was determined by UV-Vis spectroscopy and Ag-NPs size was characterised by transmission electron microscopy. The average diameter of Ag-NPs was smaller than 10 nm with narrow size distribution and the colloidal Ag-NPs have good stability for a long time of storage. The effect of several parameters, such as pH, Ag⁺ and CTS concentration and molecular weight of CTS on Ag-NPs size was also investigated. Ag-NPs of ∼7 nm exhibited highly antimicrobial effect. The inhibitory efficiency of Ag-NPs for Staphylococcus aureus was more than 99.9% at 5 ppm and the effective dose (ED₅₀) of inhibition for Corticium salmonicolor was of 27.2 ppm.

Cuprous oxide (Cu₂O) nanoparticles in zeolite A were synthesized by two steps: (i) ion-exchange of copper ions into the zeolite and (ii) reduction of copper ions in cages of the zeolite by hydrazine hydrate in base medium. The Cu₂O nanoparticles/zeolite product was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). The particle size of Cu₂O nanoparticles was of 40 nm. The antibacterial activity of the as-synthesized Cu₂O nanoparticles/zeolite against Escherichia coli was also investigated. Cu₂O NPs/zeolite product can be favorably produced on large scale for water treatment and agricultural application as antimicrobial agent.

Colloidal solutions of silver nanoparticles (AgNPs) were synthesized by gamma Co-60 irradiation using different stabilizers, namely polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), alginate, and sericin. The particle size measured from TEM images was 4.3, 6.1, 7.6, and 10.2 nm for AgNPs/PVP, AgNPs/PVA, AgNPs/alginate, and AgNPs/sericin, respectively. The influence of different stabilizers on the antibacterial activity of AgNPs was investigated. Results showed that AgNPs/alginate exhibited the highest antibacterial activity against Escherichia coli (E. coli) among the as-synthesized AgNPs. Handwash solution has been prepared using Na lauryl sulfate as surfactant, hydroxyethyl cellulose as binder, and 15 mg/L of AgNPs/alginate as antimicrobial agent. The obtained results on the antibacterial test of handwash for the dilution to 3 mg AgNPs/L showed that the antibacterial efficiency against E. coli was of 74.6%, 89.8%, and 99.0% for the contacted time of 1, 3, and 5 min, respectively. Thus, due to the biocompatibility of alginate extracted from seaweed and highly antimicrobial activity of AgNPs synthesized by gamma Co-60 irradiation, AgNPs/alginate is promising to use as an antimicrobial agent in biomedicine, cosmetic, and in other fields.

Colloidal silver nanoparticles were prepared by γ-irradiating Ag⁺ in aqueous solution in the presence of 2% polyvinyl pyrrolidone (PVP) as stabilising agent and ethyl alcohol as free radical (OH^•) scavenger. The saturated conversion dose of Ag⁺ into Ag was determined by UV–Vis spectroscopy and the silver nanoparticles size was characterised by transmission electron microscopy. The influence of Ag⁺ concentration (1–50 mM) on the saturated conversion dose and average diameter of silver nanoparticles was investigated. Results showed that the saturated conversion dose was from 8 to 48 kGy and the silver particles size was in the range of 6–21 nm for Ag⁺ concentration from 1 to 50 mM. The effect of PVP molecular weight on silver particles size was studied as well.