Biogenic silver-zinc-copper oxide nanocomposite system for antibacterial applications

Abstract

A biogenic silver-zinc-copper oxide nanocomposite system for antibacterial applications, comprising: a) a biological precursor module configured to use citrus limetta peel extract as a bioreducing and stabilizing agent; b) a metal precursor module comprising silver nitrate, zinc sulfate and copper sulfate solutions; c) a reaction module configured to perform simultaneous co-reduction of the metal precursor solutions in the presence of the biological precursor in a single vessel to form a trimetallic silver-zinc-copper oxide nanocomposite; d) a thermal processing module configured to dry and stabilize the formed nanocomposite in powder form; e) a characterization module configured to confirm the formation, composition and morphology of the nanocomposite using analytical techniques; and f) an antibacterial evaluation module configured to evaluate the bactericidal activity of the nanocomposite against pathogenic microorganisms, g) wherein the system produces a stable, environmentally friendly trimetallic nanocomposite that exhibits improved antibacterial activity.

Description

[0001] The present invention relates to the field of nanotechnology and antimicrobial materials. More specifically, it relates to a biogenic system for the synthesis of a trimetallic nanocomposite of silver-zinc-copper oxide using plant extracts. The invention further relates to antibacterial applications of the synthesized nanocomposite against pathogenic microorganisms.

[0002] Conventional antibacterial agents and metal-based nanomaterials have limitations, such as increasing resistance in microorganisms, environmental toxicity, and reliance on hazardous chemical synthesis pathways. Existing chemical and physical processes for producing metallic nanocomposites often require high energy consumption, toxic reducing agents, and expensive infrastructure, making them environmentally unsustainable and economically burdensome. These drawbacks necessitate safer and more environmentally friendly alternatives that offer effective antibacterial performance without compromising ecological and human health.

[0003] Although bimetallic and trimetallic nanocomposites have demonstrated improved antibacterial efficacy due to synergistic metal interactions, their stability, biocompatibility, and scalable synthesis remain significant challenges. Many of the described systems exhibit particle aggregation, inconsistent morphology, or poor reproducibility, which negatively impacts antibacterial efficacy. Furthermore, the use of synthetic stabilizers and surfactants raises additional toxicity concerns, limiting their applicability in the biomedical and environmental fields.

[0004] Accordingly, there is a clear need for an environmentally friendly, cost-effective, and scalable approach to developing stable antibacterial nanocomposite systems. Plant-mediated biogenic synthesis offers a promising solution by utilizing naturally occurring secondary plant metabolites as reducing and stabilizing agents. The present invention addresses these problems by providing a biogenic silver-zinc-copper oxide nanocomposite system with improved antibacterial activity, reduced environmental impact, and increased functional reliability.

[0005] One objective of this disclosure is to provide a system for the synthesis of biogenic nanocomposites that utilizes plant-based biological precursors, thereby eliminating the use of toxic chemical reducing agents and ensuring ecological sustainability. The system enables the environmentally friendly production of trimetallic nanocomposites with minimal environmental impact.

[0006] A further objective of the present disclosure is to offer an integrated one-pot reaction system capable of simultaneously reducing silver, zinc, and copper ions. This configuration simplifies the synthesis process while simultaneously improving reproducibility and operational efficiency.

[0007] A further objective of the present disclosure is to ensure improved stability and uniformity of the synthesized trimetallic nanocomposite through controlled biological stabilization and thermal processing modules. This system thereby reduces particle aggregation and improves durability.

[0008] A further objective of the present disclosure is to provide a modular system architecture that enables precise control of biological, chemical, and thermal parameters. Such modularity facilitates scalability and adaptability for applications on an industrial and laboratory scale.

[0009] A further objective of the present disclosure is to provide a nanocomposite system exhibiting synergistic antibacterial activity resulting from the combined action of silver, zinc oxide, and copper oxide components. This synergy increases the bactericidal efficacy compared to monometallic systems.

[0010] A further objective of this disclosure is the integration of integrated characterization modules for real-time validation of the formation, morphology, and composition of nanocomposites. This ensures the quality assurance and consistency of the synthesized product.

[0011] A further objective of the present disclosure is to provide an antibacterial evaluation module capable of quantitatively assessing the inhibition of microorganisms. This enables a direct correlation between system performance and functional antibacterial efficacy.

[0012] A further objective of this disclosure is to develop a cost-effective, waste-recycling-based system by using fruit peel residues as functional raw materials. This system thus supports the principles of the circular economy and sustainable material innovations.

[0013] The present invention relates generally to a modular biogenic nanocomposite synthesis and antibacterial system configured for the environmentally friendly production of a trimetallic nanocomposite of silver, zinc, and copper oxide. The system integrates biological, chemical, thermal, and functional evaluation modules to achieve sustainable synthesis with enhanced antibacterial efficacy. The invention addresses the limitations of conventional nanocomposite manufacturing processes with regard to environmental compatibility, scalability, and performance.

[0014] One embodiment of the present invention comprises a biological precursor module that uses citrus limetta peel extract as a dual-function reducing and stabilizing agent. This module enables environmentally friendly synthesis by replacing hazardous chemical reagents while simultaneously ensuring controlled nucleation and stabilization of nanoparticles within the system.

[0015] Another embodiment of the invention comprises a metal precursor module and a reaction module configured for the simultaneous co-reduction of silver, zinc, and copper ions in a single vessel. The integrated configuration ensures the homogeneous formation of a trimetallic nanocomposite with improved compositional uniformity and reproducibility.

[0016] Another embodiment of the invention relates to a thermal processing module designed to dry and stabilize the synthesized nanocomposite in powder form. This module improves the structural stability, shelf life, and ease of handling for downstream applications.

[0017] Another embodiment of the invention relates to a characterization module comprising spectroscopic and microscopic analysis units. This module validates the formation, morphology, and structural properties of the nanocomposite to ensure the consistency and reliability of system performance.

[0018] Another embodiment of the invention relates to an antibacterial evaluation module configured to assess the bactericidal performance of the synthesized nanocomposite. The module enables a quantitative evaluation of the antimicrobial efficacy and thus confirms the practical applicability of the system for biomedical and environmental purposes.

[0019] The present invention relates to a biogenic nanocomposite synthesis and antibacterial system comprising several integrated functional modules for the sustainable production and evaluation of a trimetallic silver-zinc-copper oxide nanocomposite. The system includes a biological precursor module that utilizes citrus limetta peel extract as a natural reducing and stabilizing agent, thus eliminating the need for hazardous chemicals. A metal precursor module and a one-pot reaction module enable the simultaneous co-reduction of silver, zinc, and copper ions to form a uniform trimetallic nanocomposite. A thermal processing module stabilizes the synthesized nanocomposite into a stable powder form suitable for storage and application. A characterization module ensures the confirmation of nanocomposite formation, morphology, and structural integrity through analytical techniques.An antibacterial evaluation module assesses the functional effectiveness against pathogenic microorganisms and determines the suitability of the system for biomedical and environmental applications. Biological precursor module

[0020] The biological precursor module is configured to provide a sustainable and environmentally friendly reducing and stabilizing environment for nanocomposite synthesis. This module utilizes dried and powdered Citrus limetta peels to produce an aqueous extract rich in naturally occurring secondary plant compounds such as phenols, flavonoids, and tannins. These bioactive components act simultaneously as metal ion reducing agents and capping agents, eliminating the need for external chemical reducing agents or synthetic stabilizers. The module ensures controlled extraction, filtration, and storage conditions to maintain the biochemical integrity of the extract for reproducible nanocomposite formation. Metal precursor module

[0021] The metal precursor module comprises analytical-grade silver nitrate, zinc sulfate, and copper sulfate, each prepared as separate aqueous solutions at predefined concentrations. This module is designed to deliver precise and controlled amounts of silver, zinc, and copper ions into the reaction environment. Sterile preparation and refrigerated storage conditions are maintained to prevent premature degradation, contamination, or unwanted side reactions. The module ensures a consistent availability of metal ions, which is essential for a uniform composition and reproducibility of the trimetallic nanocomposite. Reaction module

[0022] The reaction module is configured to perform a one-pot simultaneous co-reduction process, in which the metal precursor solutions are combined with the biological precursor extract under continuous stirring. In this module, phytochemicals from the plant extract initiate the nucleation and growth of silver, zinc oxide, and copper oxide nanoparticles, leading to the formation of a uniform trimetallic nanocomposite system. Controlled reaction conditions promote homogeneous particle distribution and effective integration of the metal components, resulting in a stable nanostructured product. Thermal processing module

[0023] The thermal processing module serves to transform the synthesized nanocomposite from a colloidal or semi-solid form into a stable powder material. This module applies controlled heat treatment within a defined temperature range to remove residual moisture and improve the structural stability of the nanocomposite. The drying process also contributes to improved durability and easier handling, storage, and downstream application of the nanocomposite system. Characterization module

[0024] The characterization module serves to validate the formation, composition, and physical properties of the synthesized trimetallic nanocomposite. This module includes spectroscopic tools for confirming the surface plasmon resonance properties of silver, zinc oxide, and copper oxide components, as well as microscopic tools for analyzing morphology, surface topography, and particle distribution. The module ensures that the nanocomposite meets the predefined structural and functional parameters required for antibacterial efficacy. Module for antibacterial assessment

[0025] The antibacterial evaluation module serves to assess the functional performance of the synthesized nanocomposite system against pathogenic microorganisms. This module uses standardized in vitro test methods to measure bactericidal efficacy based on the inhibition of microbial growth. The quantitative evaluation of the inhibition zones provides a direct measure of antibacterial efficacy, thus demonstrating the improved effectiveness of the biogenic silver-zinc-copper oxide nanocomposite system for biomedical and environmental applications. EXAMPLE 1: System Methodology

[0026] In an exemplary embodiment, a biogenic nanocomposite synthesis system was implemented using Citrus limetta peel extract as a biological precursor. The peels were washed, oven-dried at 70–80 °C, milled under sterile conditions, and extracted in water by heating 5 g of peel powder in 100 ml of Milli-Q water. The extract was filtered and stored at 4 °C for use as a bioreducing and stabilizing agent within the system.

[0027] The system further comprised metal precursor modules containing 1 mM aqueous solutions of silver nitrate, zinc sulfate, and copper sulfate. Under controlled conditions, these metal precursor solutions were combined with the shell extract in a one-pot reaction module to enable simultaneous co-reduction, resulting in the formation of a trimetallic silver-zinc-copper oxide nanocomposite. The synthesized product was thermally processed at 70 °C to obtain a stable powdered nanocomposite.

[0028] The system included characterization and evaluation modules for performance validation. UV-Vis spectroscopy confirmed the formation of the nanocomposite through characteristic surface plasmon resonance bands, while FESEM analysis revealed a uniform particle distribution with irregular morphology. Antibacterial evaluation against Escherichia coli showed significant bactericidal activity with a pronounced zone of inhibition at 24 mg / ml, confirming the system's effectiveness in producing a stable and highly active antibacterial nanocomposite.