AgNPs-incorporated nanofiber mats: Relationship between AgNPs size/content, silver release, cytotoxicity, and antibacterial activity

Highlights: • AgNPs were incorporated into starch nanofiber mats with in situ reduction method. • The size and content of AgNPs together controlled the release behavior of silver. • The size and content of AgNPs governed the cytotoxicity of the mats. • The content of AgNPs determined the antibacterial activity of the mats. • The mats showed good antibacterial property and excellent cytocompatibility. Silver nanoparticles (AgNPs) have a wide antimicrobial spectrum and low incidence of resistance. They have been widely incorporated into wound dressings for antimicrobial purpose. However, these wound dressings suffer from the accompanied cytotoxicity. It is important but challenging for them to reduce the cytotoxicity without compromising antimicrobial activity, while the affecting factors are unknown. In this work, we incorporated AgNPs into starch nanofiber mats with the in situ reduction method, and investigated the structure and property of the composite nanofiber mats in detail. We found that the cytotoxicity and antibacterial activity of the starch/AgNPs composite nanofiber mats are both affected by the release behavior of silver from the mats, while of various stages and governing factors. The cytotoxicity of the mats depends on the silver release rate at the early stage, which is governed by both the size and content of the AgNPs. The antibacterial activity is more related to the silver release rate at the later stage and is determined mainly by the content of AgNPs. By optimizing the size and content of AgNPs, we found a safe window and obtained starch/AgNPs composite nanofiber mats with good antibacterial activity and excellent cytocompatibility as well. The composite nanofiber mats also showed moderate wet strength (1–2 MPa), high liquid absorption capability (19–34 times of their own weights) and suitable vapor permeability [0.22–0.26 g/(cm²·24 h)]. These starch/AgNPs composite nanofiber mats are ideal candidates for the treatment of infected and exuding wounds.