Development of antimicrobial biomaterials produced from chitin-nanofiber sheet/silver nanoparticle composites

Abstract

BackgroundChitin nanofibers sheets (CNFSs) with nanoscale fiber-like surface structures are nontoxic and biodegradable biomaterials with large surface-to-mass ratio. CNFSs are widely applied as biomedical materials such as a functional wound dressing. This study aimed to develop antimicrobial biomaterials made up of CNFS-immobilized silver nanoparticles (CNFS/Ag NPs).Materials and methodsCNFSs were immersed in suspensions of Ag NPs (5.17 ± 1.9 nm in diameter; mean ± SD) for 30 min at room temperature to produce CNFS/Ag NPs. CNFS/Ag NPs were characterized by transmission electron microscopy (TEM) and then tested for antimicrobial activities against Escherichia (E.) coli, Pseudomonas (P.) aeruginosa, and H1N1 influenza A virus, three pathogens that represent the most widespread infectious bacteria and viruses. Ultrathin sectioning of bacterial cells also was carried out to observe the bactericidal mechanism of Ag NPs.ResultsThe TEM images indicated that the Ag NPs are dispersed and tightly adsorbed onto CNFSs. Although CNFSs alone have only weak antimicrobial activity, CNFS/Ag NPs showed much stronger antimicrobial properties against E. coli, P. aeruginosa, and influenza A virus, with the amount of immobilized Ag NPs onto CNFSs.ConclusionsOur results suggest that CNFS/Ag NPs interacting with those microbes exhibit stronger antimicrobial activities, and that it is possible to apply CNFS/Ag NPs as anti-virus sheets as well as anti-infectious wound dressings.

Cytotoxicity of Silver Nanoparticle and Chitin-Nanofiber Sheet Composites Caused by Oxidative Stress

“…In our previous studies, Ag NPs were stably adsorbed onto chitin/chitosan powders [6,28] and sheets [29] with nanoscale fiber-like surface structures. In those applications, Ag NPs/chitin/chitosan composites showed enhanced stability of Ag NPs and exhibited strong antimicrobial (antiviral, bactericidal, and antifungal) activities.…”

“…In the previous studies, chitin-nanofiber sheets (CNFS) were used to adsorb and to stabilize Ag NPs, remove the caramel generated during autoclaving, and prevent aggregation and precipitation of Ag NPs. Ag NPs were homogenously dispersed and stably adsorbed onto CNFS with nanoscale fiber-like surface structures [29]. Subsequent studies showed that the bactericidal, antifungal, and antiviral activities of Ag NPs/CNFS increased with Ag NP adsorption, indicating potential applications of CNFS as novel stabilizers and carriers for Ag NPs [27,29].…”

“…Ag NPs were homogenously dispersed and stably adsorbed onto CNFS with nanoscale fiber-like surface structures [29]. Subsequent studies showed that the bactericidal, antifungal, and antiviral activities of Ag NPs/CNFS increased with Ag NP adsorption, indicating potential applications of CNFS as novel stabilizers and carriers for Ag NPs [27,29]. On the other hand, Ag NPs have exhibited various degrees of in vitro and in vivo cytotoxicity [10].…”

“…On the other hand, Ag NPs have exhibited various degrees of in vitro and in vivo cytotoxicity [10]. Moreover, despite the acceptance of chitin/chitosan as a suitable biocompatible carrier agent for Ag NPs [27,29], no study has investigated the cytotoxicity of Ag NPs/CNFS. It is necessary to fully understand the cytotoxicity of Ag NPs/CNFS in dermal applications and its mechanism of action, thereby ensuring its safety in clinical applications as an anti-infectious wound dressing.…”

Preparation of DNA-immobilized magnetic particles and their utilization as an accumulative material of metal ions

“…Metal oxide particles have many functions, such as optical properties, 23,24 catalytic activities, 25 antimicrobial activities, 26 and the absorption properties. 27 Therefore, the metal oxide particles have been used as engineering materials, catalysts, absorbents, and biomedical materials.…”