Silver nanoparticles, also known as AgNPs, have been extensively researched due to their one-of-a-kind characteristics, including their optical, antibacterial, and electrical capabilities. In the era of the antibiotics crisis, with an increase in antimicrobial resistance (AMR) and a decrease in newly developed drugs, AgNPs are potential candidates because of their substantial antimicrobial activity, limited resistance development, and extensive synergistic effect when combined with other drugs. The effect of AgNPs depends on the delivery system, compound combination, and their own properties, such as shape and size, which are heavily influenced by the synthesis process. Reduction using chemicals or light, irradiation using gamma ray, laser, electron beams or microwave and biological synthesis or a combination of these techniques are notable examples of AgNP synthesis methods. In this work, updated AgNP synthesis methods together with their strength and shortcomings are reviewed. Further, factors affecting the synthesis process are discussed. Finally, recent advances and challenges are considered.

The findings from Pareto charts, main effect plots, and interaction plots demonstrate the importance of polymer concentration. Increasing concentration improves the inhibition percentage and decreases the MIC₅₀. However, the primary factor that influences these changes is chitosan (CS). Additionally, the interaction between CS and PVP, along with other polymers, plays a crucial role in achieving better antimicrobial effects. These results enhance our understanding of the antimicrobial properties of the studied polymers and offer valuable insights for developing effective antimicrobial formulations. The MIC₅₀ value of M1–M16 was at a polymer percentage of 12.5%. At 12.5% polymer percentage, with the limits of [PVA], [PEG], and [PVP] being 0.002–0.004 g/mL and [CS] being 0.001–0.002 g/mL, using the 2-level full factorial method, the inhibition percentage is equal to 174.1 − 27,812 PVA − 18,561 PVP − 25,960 PEG − 38,752 CS + 9,263,047 PVA*PVP + 10,430,763 PVA*PEG + 15,397,157 PVA*CS + 7,088,313 PVP*PEG + 7,841,221 PVP*CS + 14,228,046 PEG*CS − 3,367,292,860 PVA*PVP*PEG − 5,671,998,721 PVA*PVP*CS − 6,619,041,275 PVA*PEG*CS − 3,917,095,529 PVP*PEG*CS + 2,273,661,969,470 PVA*PVP*PEG*CS. Theoretically, the most economical concentrations of PVA, PVP, PEG, and CS are 0.002, 0.002, 0.002, and 0.001 mg/mL at a concentration of 12.5% to reach an inhibition percentage of 99.162%, which coincides with the MBC value.

Synthetic dye contamination of wastewater has long been a social issue, with adsorption being the most focused upon research technique among wastewater treatment. Using the co-precipitation method, superparamagnetic iron oxide nanoparticles (SPIONs) with the size of 13.6 ± 1.9 nm were synthesized. By adsorbing methylene blue (MB) on the modified surface of SPIONs using polyvinyl alcohol, chitosan, and graphene oxide, the entrapment efficiency at pH 7 can be up to 87.00 ± 0.16% after 13 days, and the highest MB loading capacity was 3.638 ± 0.009%, while the highest loading amount achieved was 36.385 ± 0.095 mg/g. The cumulative desorption capacity of the adsorbent at pH 3.8 was at its maximum at 8.94 ± 0.66% after 30 days. The results of the experiments indicated that the compound has a favorable impact on the adsorption of synthetic dyes; nevertheless, more research is needed to determine the ideal ratio, temperature, and pH levels for this chemical.