The Antibacterial Effect of Jellyfish-Like pMAG-Au-MnO₂ Nanoparticles

Manganese (Mn) has been widely applied in drug resistant bacteria. Although it has advantages such as generating reactive oxygen species (ROS), holding multivalent phases, inducing photothermal effect and biocompatibility, it also brings the disadvantages of increased motility and decreased bacterial adhesion while exerting its advantages. Here, we propose an active antibacterial way by the jellyfish-like anisotropic nanocomposites (JAN), which measures both the advantages and disadvantages of MnO2 nanoparticles (MnNP) together. In this jellyfish-like construct, the spheric gold nanoparticles (AuNP) were covered by MnO2 nanosheets (MnNS), only leaving a bunch of glycopolymers (pMAG) stretching out from a small surface area of AuNP. In JAN, AuNP serves as the main body, possessing a photothermal property; glycopolymers play as the tentacles, binding specifically with Escherichia coli (E. coli); MnNS acts as the shell of jellyfish, initiating by the photo treatment to kill bacteria. The structure and surface properties of JAN were characterized by water contact angle (WCA), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), ultraviolet and visible spectrophotometry (UV-Vis), transmission electron microscope (TEM), dynamic light scattering (DLS), and ellipsometry. The specific antibacterial effect of JAN was evaluated on the growth of both Gram-negative E. coli and Gram-positive Staphylococcus aureus (S. aureus). The results showed that JAN could bind efficiently with E. coli and kill almost all bacteria under near infrared (NIR irradiation, 808nm) irradiation for as short as 7 min. This antibacterial effect of JAN can be attributed to their excellent photothermal and photodynamic properties in increasing the temperature to higher than 53 & LCIRC;C and ROS more than 0.45 mmol/L, indicating that the JAN achieved specific and efficient bactericidal effect due to their unique nanostructure and surface properties. In this study, we report for the first time on the synthesis strategy of jellyfish-like anisotropic nanoparticles and their specific bactericidal effect. Our work provides new possibilities for the application of anisotropic nanoparticles to inhibit bacterial growth.