Green Synthesis and Durable Antibacterial AgNP-Loaded Alginate Fibers Enabled by Microfluidic Technology Coupled with Ultraviolet/Thermal Fields

Abstract

With the increasing health and environmental awareness, a growing demand for health-safe textiles has sparked significant interest in antibacterial alginate fibers loaded with silver nanoparticles (AgNPs). However, the existing preparation methods suffer from issues such as non-eco-friendly solvents, process inefficiency, and short-lasting antibacterial durability, limiting their applications. In this study, a simple, green, and efficient synthesis process for AgNPs was developed using the microfluidic technology coupled with ultraviolet/thermal fields, which produced nanoparticles with a uniform size (13.0 ± 3.2 nm) and long-term stability (>4 months). Based on this method, a sodium alginate-based spinning process was designed to achieve in situ reduction of AgNPs during fiber spinning, with the silver loss controlled within 20%, a result seldom documented in the literature. Moreover, this process avoided interference from other reagents and ensured uniform distribution of AgNPs inside and on the surface of the fibers. More importantly, the AgNP-loaded fibers exhibited 99.99% highly efficient antibacterial activity against Staphylococcus aureus and Escherichia coli with a remarkably low AgNP content of 2000 mg·kg^–1. Even after 50 washes, the antibacterial effect was still maintained at 96.88% and 95.05%, demonstrating excellent long-lasting antibacterial performance and significant application prospects.