Microenvironment-Responsive Magnetic Nanocomposites Based on Silver Nanoparticles/Gentamicin for Enhanced Biofilm Disruption by Magnetic Field

Abstract

Biofilms contribute to persistent bacterial infections as well as formidable resistances to conventional antibiotics. However, it is still a major challenge to establish an advanced antibacterial nanoplatform that can efficiently eradicate biofilms while overcoming bacterial resistances. Taking advantage of the stimuli-responsive technique and the magnetic guidance strategy, here we present a highly efficient nanoplatform for planktonic inactivation and biofilm disruption. The multilayer films consisting of antibiotic gentamicin (Gen), tannic acid, and silver nanoparticles (AgNPs) were fabricated and coated on magnetic nanoparticles via electrostatic interactions. To achieve controlled drug release and improved biocompatibility, biodegradable hyaluronic acid was capped on the outer surface as a responsive shell. In vitro release profiles suggested that the nanocomposites showed both enzyme and pH-responsive release properties. The nanoplatform could be employed as a powerful nanocarrier for small molecular Gen and AgNPs delivery and on-demand release in response to bacterial infection microenvironment. The nanocomposites also showed satisfying antibacterial capacities against planktonic Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. Intriguingly, with magnetic field navigation (NdFeB, 2000 gauss), the nanocomposites could be guided to handily penetrate into S. aureus biofilm and performed dual-responsive release, showing significantly enhanced biofilm disruption. Moreover, excess reactive oxygen species production resulting from the nanocomposites contributed to the decomposition of biofilm matrix and ultimate biofilm eradication. As a consequence, the ingenious antibacterial nanoplatform could be promising for combating biofilm infections while overcoming bacterial resistances with extra environmental factors such as magnetic field.

Silver nanoparticles exert concentration‐dependent influences on biofilm development and architecture

“…However, single Ag nanoparticle tends to aggregate owing to its high surface energy resulted from large specific surface area . To overcome the drawback, various AgNPs‐based composites are fabricated such as graphene oxide(GO)‐AgNPs and magnetic nanoparticles(MNP)@AgNPs, which can improve the stability of AgNPs, and provide synergistic antibacterial and anti‐biofilm effect superior to single AgNPs . Notably, most of these studies conducted with the final inhibition efficacy of AgNPs, namely, how to obtain the optimal lethal concentration that is toxic to microorganisms but safe for human and environment.…”

Innovative Strategies Toward the Disassembly of the EPS Matrix in Bacterial Biofilms

“…For instance, Wang et al produced highly efficient nanoplatforms, consisting of gentamicin, tannic acid and AgNPs coated on MNPs, to test against established biofilms of S. aureus. Additionally to the MNPs expected effect, the presence of AgNPs caused the production of reactive oxygen species (ROS), which enhanced decomposition of polysaccharides and proteins of the EPS matrix (Wang et al, 2018a). Iron oxideencapsulating polymersomes, containing both hydrophobic SPIONs and the hydrophilic antibiotic methicillin, were also developed to eradicate antibiotic-resistant infections associated with 24 h-old S. epidermidis biofilms (Geilich et al, 2017).…”

Silver Nanoparticles for Water Pollution Monitoring and Treatments: Ecosafety Challenge and Cellulose-Based Hybrids Solution

“…In fact, thanks to the high surface-to-volume ratio, they allow a better interaction with analytes. Furthermore, the possibility of modulating size, shape and functionalization allows their chemical-physical properties to be controlled, such as optical or assembly properties, in order to adapt them to specific needs [ 43 , 44 , 45 , 46 , 47 , 48 ].…”