Green Synthesis of Antimicrobial Nanocomposites

Green synthesis of antimicrobial nanocomposites harnesses biological agents such as plant extracts, microbial metabolites or biowaste as reducing and capping agents to produce metal- or metal-oxide-based nanoscale hybrids. By replacing harsh chemicals with renewable biomolecules—polyphenols, proteins or polysaccharides—this approach minimises toxic by-products and energy consumption. Commonly studied systems combine zinc oxide and silver within a single matrix to exploit synergistic antimicrobial mechanisms: membrane disruption, metal ion release and generation of reactive oxygen species. The incorporation of support materials such as biochar, activated carbon or polymeric hydrogels enhances dispersibility, reusability and photocatalytic performance under visible light. Practical applications span water disinfection, surface coatings for medical devices and textile treatments. Beyond microbial control, these eco-friendly nanocomposites offer dual functionality by degrading organic pollutants via photocatalysis. Ongoing research addresses challenges in scalability, uniform particle size, long-term stability and precise control of metal loading, with an overarching goal of delivering cost-effective, sustainable antimicrobials for global health and environmental protection.

Research from Nature Portfolio

Recent studies have demonstrated the effective phytofabrication of silver-zinc oxide composites supported on biochar derived from agricultural residues. Optimisation of metal precursor ratios, pH and temperature yielded nanocomposites with average diameters below 20 nm and marked antibacterial activity against multidrug-resistant strains, while retaining over half of their photocatalytic performance after multiple reuse cycles. In a complementary investigation, leaf extracts of Tetradenia riperia served as both reducing and stabilising agents in a one-step synthesis of Ag–ZnO hybrids. Fine tuning of silver concentration and reaction parameters produced composites with sub-15 nm crystallites that achieved rapid inactivation of Escherichia coli and Staphylococcus aureus in water. Both works underline the role of phytochemicals in controlling morphology, enhancing colloidal stability and ensuring potent antimicrobial efficacy under mild conditions.

Green Synthesis of Antimicrobial Nanocomposites publication trend

The graph below shows the total number of articles in green synthesis of antimicrobial nanocomposites across all publications each year (not limited to Nature Index journals).

Technical terms

Green synthesis: A method of producing nanoparticles using biological agents to reduce environmental impact.

Nanocomposite: A hybrid material comprising nanoscale components integrated within a matrix to combine distinct functionalities.

Phytofabrication: The use of plant-derived extracts as reducing and stabilising agents in nanoparticle synthesis.

Photocatalysis: A process in which light energy activates a semiconductor to degrade pollutants or inactivate microorganisms.

Reactive oxygen species (ROS): Highly reactive molecules such as hydroxyl radicals generated at nanoparticle surfaces that contribute to antimicrobial action.

References

1. Green synthesis of bimetallic Ag/ZnO@Biohar nanocomposite for photocatalytic degradation of tetracycline, antibacterial and antioxidant activities. Scientific Reports (2022).
2. In situ facile green synthesis of Ag–ZnO nanocomposites using Tetradenia riperia leaf extract and its antimicrobial efficacy on water disinfection. Scientific Reports (2022).
3. Green Facile Synthesis of Silver-Doped Zinc Oxide Nanoparticles and Evaluation of Their Effect on Drug Release. Materials (2022).
4. A Comparative Study of Antibacterial Activity of CuO/Ag and ZnO/Ag Nanocomposites. Advances in Materials Science and Engineering (2020).
5. Green Synthesis of an Activated Carbon-Supported Ag and ZnO Nanocomposite for Photocatalytic Degradation and Its Antibacterial Activities. Molecules (2020).