The growing concern over antimicrobial resistance has driven research into sustainable alternatives to conventional antibiotics, particularly in textiles where microbial contamination poses health risks. One promising approach involves upcycling eggshell membrane waste into silver nanoparticle-loaded nanocomposites for antimicrobial fabrics. This method combines waste valorization with green nanotechnology to create effective, eco-friendly textile solutions.

Eggshell membranes, typically discarded as agricultural waste, possess a unique fibrous protein structure rich in collagen, elastin, and glycosaminoglycans. These biomolecules serve as effective reducing and stabilizing agents for the synthesis of silver nanoparticles (AgNPs), eliminating the need for harsh chemical reagents. The process begins with the collection and purification of eggshell membranes, which are washed to remove residual albumen and dried. The membranes are then immersed in a silver nitrate solution, where the functional groups present—such as carboxyl, amine, and hydroxyl—reduce silver ions to metallic AgNPs, anchoring them onto the fibrous scaffold. The reaction proceeds at mild temperatures, often between 50-80°C, with nanoparticle formation confirmed by a color change to brown or dark yellow.

Characterization of these nanocomposites reveals AgNPs with sizes ranging from 10-50 nm, uniformly distributed across the membrane matrix. Electron microscopy and X-ray diffraction confirm the crystalline nature of the nanoparticles, while spectroscopy techniques verify the absence of toxic chemical residues. The eggshell membrane not only facilitates nanoparticle synthesis but also enhances stability, preventing agglomeration—a common issue in conventional colloidal AgNP preparations.

Integration of these nanocomposites into textiles is achieved through several methods, with electrospinning being particularly effective. The eggshell membrane-AgNP composite can be processed into a powder and blended with polymers such as polyvinyl alcohol (PVA) or polylactic acid (PLA) to form nanofiber mats. Electrospinning parameters, including voltage, flow rate, and polymer concentration, are optimized to produce fibers with diameters in the 100-500 nm range. These nanofibers exhibit high surface area-to-volume ratios, enhancing antimicrobial activity by maximizing nanoparticle exposure. Alternatively, the nanocomposite can be applied as a coating onto existing fabrics via dip-coating or spray deposition, followed by thermal or chemical cross-linking to ensure durability.

The antimicrobial efficacy of these textiles is tested against multidrug-resistant pathogens such as methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, and Candida albicans. Studies demonstrate significant reductions in bacterial viability, often exceeding 99% within 24 hours of contact. The mechanism involves the release of silver ions, which disrupt microbial cell membranes, inhibit respiration, and damage DNA. Unlike conventional antimicrobial textiles that rely on leaching synthetic agents like triclosan or quaternary ammonium compounds, the eggshell-derived nanocomposites offer sustained activity without rapid depletion or environmental toxicity.

Comparisons with synthetic antimicrobial textiles highlight key advantages. Traditional silver-coated fabrics often use chemically synthesized AgNPs, requiring stabilizers like polyvinylpyrrolidone (PVP) or citrate, which may pose biocompatibility concerns. In contrast, the eggshell membrane scaffold provides natural stabilization, reducing the risk of nanoparticle release during washing. Additionally, synthetic methods frequently involve high energy consumption or toxic solvents, whereas the eggshell-based process operates under greener conditions. Durability tests show that the bio-nanocomposite textiles retain antimicrobial properties after multiple wash cycles, outperforming some polymer-based counterparts that degrade due to weak nanoparticle adhesion.

Environmental and economic benefits further distinguish this approach. Eggshell waste, which constitutes millions of tons annually, is repurposed rather than landfilled, reducing disposal costs and environmental impact. The process avoids expensive reagents and complex purification steps, lowering production costs compared to conventional AgNP synthesis. Lifecycle assessments indicate a smaller carbon footprint due to reduced chemical use and milder processing conditions.

Despite these advantages, challenges remain. Scaling up production while maintaining nanoparticle uniformity requires optimization, and long-term studies are needed to assess wear-and-tear effects on antimicrobial performance. Regulatory approval for biomedical textiles may necessitate additional toxicological data, though current evidence suggests minimal cytotoxicity to human skin cells.

In summary, eggshell membrane waste upcycled into silver nanoparticle-loaded nanocomposites presents a viable, sustainable alternative to synthetic antimicrobial textiles. The green synthesis leverages natural biomolecules for nanoparticle formation, while electrospinning or coating methods enable seamless integration into fabrics. With proven efficacy against resistant pathogens and superior environmental profiles, these bio-nanocomposites align with global efforts to combat antimicrobial resistance through circular economy principles. Future work should focus on industrial-scale processing and broader applications in protective clothing, hospital linens, and sportswear.