A Nanocomposite Hydrogel with Potent and Broad-Spectrum Antibacterial Activity

Abstract

Local bacterial infection is a challenging task and still remains a serious threat to human health in clinics. Systemic administration of antibiotics has only short-term antibacterial activity and usually causes adverse effects and bacterial resistance. A bioadhesive hydrogel with broad-spectrum and on-demand antibiotic activity is highly desirable. Here, we designed a pH-responsive nanocomposite hydrogel via a Schiff base linkage between oxidized polysaccharides and cationic dendrimers encapsulated with silver nanoparticles. The antibacterial components, both the cationic dendrimers and silver species, could be released in response to the acidity generated by growing bacteria. The released cationic polymer and silver exhibited a synergistic effect in antibacterial activity, and thus, the nanocomposite hydrogel showed potent antibacterial activity against both Gram-negative ( Escherichia coli and Pseudomonas aeruginosa) and Gram-positive bacteria ( Staphylococcus epidermidis and Staphylococcus aureus). The gel showed superior in vivo antibacterial efficacy against S. aureus infection compared with a commercial silver hydrogel at the same silver concentration. In addition, no obvious hemolytic toxicity, cytotoxicity, and tissue and biochemical toxicity were observed for the antibacterial hydrogel after incubation with cells or implantation. This study provides a facile and promising strategy to develop smart hydrogels to treat local bacterial infections.

Nanoparticle–Polymer Synergies in Nanocomposite Hydrogels: From Design to Application

“…Metal and metal‐oxide NPs possess these unique properties that cannot be obtained from polymers. Due to the intrinsic antibacterial, ferromagnetic, and conducting properties, metal and metal‐oxide NPs can provide NC gels with antimicrobial activity, magnetic and electrical properties which are suitable for biomedical applications. Therefore, metal and metal‐oxide NPs are ideal reinforcing materials with great potential in preparing NC gels with unique characteristics and tunable properties .…”

Needle-injectable microcomposite cryogel scaffolds with antimicrobial properties

“…Common biomedical implant-related pathogens include Staphylococcus aureus ( S. aureus ), Escherichia coli ( E. coli ), and Pseudomonas aeruginosa ( P. aeruginosa ). Complications from implant-related infections can impede tissue regeneration, delay wound healing 59 , and induce the development of biofilms that can require > 1000 times higher doses of antibiotics for effective treatments 16 , 62 – 64 . To address this challenge, diverse strategies have been deployed to prevent microbial contamination of biomaterials.…”

“…To address this challenge, diverse strategies have been deployed to prevent microbial contamination of biomaterials. Some of the strategies have relied on developing antibiotic-containing surface coatings or incorporating antimicrobial peptides within biomaterial constructs 46 , 62 , 64 – 69 . However, a number of limitations of these approaches still remain.…”

Nanolayers of Poly(N,N′-Dimethylaminoethyl Methacrylate) with a Star Topology and Their Antibacterial Activity

“…Over the past decade, a variety of modifications or treatment techniques has emerged to obtain efficient antibacterial surfaces [1]. Polymeric materials with antibacterial properties are extensively studied in the form of a bactericidal polymer on its own [2][3][4][5][6], physical loading of a biocidal active substance (biocide) into a polymer [7][8][9][10][11][12][13][14][15][16], or a chemical functionalization with a bactericidal or bacteriostatic compound [17][18][19][20][21][22][23]. The antibacterial activity of biocide loaded in the polymer is caused by its diffusion, while surfaces modified with polycations kill bacteria through direct contact.…”