Enzyme-Responsive Ag Nanoparticle Assemblies in Targeting Antibacterial against Methicillin-Resistant Staphylococcus Aureus.

The abuse of antibiotics resulted in the emergence of antibiotics-resistant bacteria, which has raised a great social concern together with the impetus to develop effective antibacterial materials. Herein, the synthesis of biocompatible enzyme-responsive Ag nanoparticle assemblies (ANAs) and their application in the high-efficiency targeted antimicrobial treatment of methicillin-resistant Staphylococcus aureus (MRSA) have been demonstrated. The ANAs could collapse and undergo stable/collapsed transition on approaching MRSA because of the serine protease-like B enzyme proteins (SplB)-triggered decomposition of the branched copolymers which have been employed as the macrotemplate in the synthesis of responsive ANAs. This transition contributed greatly to the high targeting affinity and efficiency of ANAs to MRSA. The minimum inhibitory concentration and minimum bactericidal concentration against MRSA were 2.0 and 32.0 µg mL-1, respectively. Skin wound healing experiments confirmed that the responsive ANAs could serve as an effective wound dressing to accelerate the healing of MRSA infection.

Unimolecular branched block copolymer nanoparticles in methanol for the preparation of poorly water-soluble drug nanoparticles.

Spherical unimolecular amphiphilic branched A-B block copolymer nanoparticles in methanol are fabricated via thermal annealing using the methanolic upper critical solution temperature (UCST) of the hydrophobic block segment. These polymer nanoparticles are then used to produce an aqueous poorly water-soluble drug nanoparticle suspension with a mass : drug ratio of 1 : 1 and 100% nanoparticle yield. The drug nanoparticles in the suspension are stabilized by multiple polymer nanoparticles.