Abstract
Adsorbing small charged nanoparticles onto the outer surfaces of liposomes has become an effective strategy to stabilize liposomes against fusion prior to "seeing" target bacteria, yet allow them to fuse with the bacteria upon arrival at the infection sites. As a result, nanoparticle-stabilized liposomes have become an emerging drug delivery platform for treatment of various bacterial infections. To facilitate the translation of this platform for clinical tests and uses, herein we integrate nanoparticle-stabilized liposomes with hydrogel technology for more effective and sustained topical drug delivery. The hydrogel formulation not only preserves the structural integrity of the nanoparticle-stabilized liposomes, but also allows for controllable viscoeleasticity and tunable liposome release rate. Using Staphylococcus aureus bacteria as a model pathogen, we demonstrate that the hydrogel formulation can effectively release nanoparticle-stabilized liposomes to the bacterial culture, which subsequently fuse with bacterial membrane in a pH-dependent manner. When topically applied onto mouse skin, the hydrogel formulation does not generate any observable skin toxicity within a 7-day treatment. Collectively, the hydrogel containing nanoparticle-stabilized liposomes hold great promise for topical applications against various microbial infections.