Owing to the existence of the outer membrane barrier, most antibacterial agents cannot penetrate Gram-negative bacteria and are ineffective. Here, we report a general method for narrow-spectrum antibacterial Garcinia nanoparticles that can only be effective to kill Gram-positive bacteria, to effectively eliminate Gram-negative bacteria by creating transient nanopores in bacterial outer membrane to induce drug entry under microwaves assistance. In vitro, under 15 min of microwaves irradiation, the antibacterial efficiency of Garcinia nanoparticles against Escherichia coli can be enhanced from 6.73% to 99.48%. In vivo, MV-assisted GNs can effectively cure mice with bacterial pneumonia. The combination of molecular dynamics simulation and experimental results reveal that the robust anti-E. coli effectiveness of Garcinia nanoparticles is attributed to the synergy of Garcinia nanoparticles and microwaves. This work presents a strategy for effectively treating both Gram-negative and Gram-positive bacteria co-infected pneumonia using herbal medicine nanoparticles with MV assistance as an exogenous antibacterial auxiliary.

Engineered probiotics biofilms prevent MRSA infection and improve bone integration through immunoregulation.

To endow Ti-based orthopedic implants with strong bactericidal activity, a ZnO nanorods-patterned coating (namely ZNR) was fabricated on Ti utilizing a catalyst- and template-free method of micro-arc oxidation (MAO) and hydrothermal treatment (HT). The coating comprises an outer layer of ZnO nanorods and a partially crystallized inner layer with nanocrystalline TiO₂ and Zn₂TiO₄ embedded amorphous matrix containing Ti, O and Zn. During HT, Zn²⁺ ions contained in amorphous matrix of the as-MAOed layer migrate to surface and react with OH⁻ in hydrothermal solution to form ZnO nuclei growing in length at expense of the migrated Zn²⁺. ZNR exhibits intense bactericidal activity against the adhered and planktonic S. aureus in vitro and in vivo. The crucial contributors to kill the adhered bacteria are ZnO nanorods derived mechano-penetration and released reactive oxygen species (ROS). Within 30 min of S. aureus incubation, ROS is the predominant bactericidal contributor with quantitative contribution value of ∼20%, which transforms into mechano-penetration with prolonging time to reach quantitative contribution value of ∼96% at 24 h. In addition, the bactericidal contributor against the planktonic bacteria of ZNR is relied on the released Zn²⁺. This work discloses an in-depth bactericidal mechanism of ZnO nanorods.