•A novel AgNPs-BC/CA composite was prepared by a simple and facile method.•It got higher mechanical properties than pure BC due to its unique microstructure.•The water swelling ability of AgNPs-BC/CA composite was 4.08 times that of pure BC.•A high and prolonged antibacterial effect was obtained by this composite.•AgNPs-BC/CA composite film could be a desirable biomedical material.Bacterial cellulose (BC) has attracted more and more attentions as a biomedical material. However, pure BC possesses a poor mechanical strength in a wet state, a weak water swelling ability after drying as well as no antibacterial activity. To resolve this, a kind of novel silver nanoparticles (AgNPs) impregnated bacterial cellulose/calcium alginate (BC/CA) composite film was fabricated for the first time using a new form of BC/CA double-network (DN) film as the template to in situ synthesize AgNPs by a facile method, UV irradiation. This composite realized obvious improvements in both the mechanical property (fracture strength and fracture strain) and the water swelling ability, with values of 2.97, 1.41 and 4.08 times, respectively, those of pure BC, as well as a high and prolonged antibacterial effect for more than 48 h.Download high-res image (140KB)Download full-size image

•BC/PAM composite was utilized as the template to in situ synthesize AgNPs.•A green route was proposed to synthesize AgNPs by UV irradiation.•Influences of the templates, i.e., BC/PAM and BC were investigated on AgNPs synthesis.•A lower silver content and higher particle size of AgNPs were got by BC/PAM-AgNPs.•High antibacterial effects were got by BC/PAM-AgNPs and BC-AgNPs nanocomposites.In this work, a bacterial cellulose/polyacrylamide (BC/PAM) double network composite was prepared to act as the template for in situ synthesis of silver nanoparticles (AgNPs). Effects of reaction conditions of the BC/PAM composite were investigated on its microstructure, mechanical properties and thermal stabilities. Both the BC/PAM composite and pure BC were utilized to prepare the corresponding silver impregnated nanocomposites, i.e., BC/PAM-AgNPs and BC-AgNPs, by an environmental friendly method, UV irradiation. The influences of the templates were investigated on the AgNPs formation and the antibacterial activities of the nanocomposites by both the zone of inhibition and dynamic shake flask methods. It was shown that the BC/PAM composite displayed a denser microstructure and higher thermal stabilities than pure BC. The BC/PAM-AgNPs nanocomposite exhibited a bigger particle size and lower mass content of AgNPs than the BC-AgNPs one. For the antibacterial test, two nanocomposites exhibited a close antibacterial effect, with a high log reduction above 3 and killing ratio above 99.9%, respectively.

Antibacterial materials based on cellulose have been widely used in many fields. In this work, an environmentally benign and facile approach for production of silver nanoparticles (AgNPs) was proposed for the first time by hydrothermal synthesis using bacterial cellulose (BC) as both the reducing and stabilizing agent, without any chemical reagents introduced. Some key reaction parameters were optimized to achieve a high antibacterial activity of the BC/AgNPs composite. Under the optimal conditions, a small size and a narrow distribution of AgNPs, 17.1 ± 5.9 nm, was formed on the BC matrix, with a silver content of 1.78% (w/w) and a MIC value of 1.30 × 10−4 μg/CFU. Moreover, a sustained release of silver and a prolonged antibacterial performance of the composite against Staphylococcus aureus were found over a long period time of 72 h, which were important for practical applications.Highlights► A green route was proposed to synthesize AgNPs by hydrothermal synthesis. ► AgNPs of small size (17 nm) were synthesized on BC matrix. ► BC served as both the reducing and stabilizing agent in a gently heated system. ► Long-term antibacterial performance was obtained by BC/AgNPs composites.