Green continuous preparation of silver-loaded helical alginate composite fibers based on microfluidic technology

In order to enhance the antimicrobial properties of helical fiber and ensure its safety and stability in various applications, it is crucial to address the compatibility issues of preparation reagents between the antibacterial agent and alginate fiber. These compatibility issues often lead to complex blending and spinning processes, which pose challenges in achieving the desired helical morphology and performance of the composite fibers. To overcome these challenges, this study utilizes environmentally friendly sodium citrate (TSC) as the reducer and stabilizer for silver nanoparticles (AgNPs) antimicrobial agents and meanwhile a shaping promoter for the helical morphology of alginate fiber. A continuous spinning system for silver-loaded helical alginate composite fiber was established using microfluidic technology. The morphology, mechanical properties, thermal stability, release of silver, and antibacterial properties of the helical composite fibers were characterized. The results show that AgNPs have a spherical shape with a uniform particle size ranging from 4 nm to 12 nm, and can be evenly distributed inside the fiber during the continuous spinning. Additionally, increasing the loading amount of AgNPs not only can enhance the fracture strength and thermal stability, but also promote the formation of helical composite fibers, resulting in significantly higher elongation at break and elasticity compared to linear composite fibers. When the loading of AgNPs is greater than 200 mg/kg, the antibacterial rate can reach over 99.9%, and it has long-lasting, efficient antimicrobial potential. This study provides a theoretical basis for the performance regulation of antimicrobial alginate fibers and technical guidance for the continuous and precise construction of composite materials.