ACS Nano http://doi.org/rhp (2014)

Turning laboratory research into real-world applications is a significant challenge. For nanoparticle-based drug delivery, the development of robust formulations of nanotherapeutics with minimal toxicity is an important step towards this goal. Weiwei Gao and colleagues at the University of California, San Diego and Tsinghua University now show that a robust, non-toxic formulation for topical antimicrobial delivery can be created by incorporating nanoparticle-stabilized liposomes into a hydrogel.

Decoration with gold nanoparticles stabilized the biocompatible liposomes and prevented liposome fusion before reaching the bacterial target. However, a sufficient amount of the liposome surface was still exposed to allow bacterial toxins to access the surface and trigger cargo release from the liposomes. Integration into the hydrogel preserved the structural integrity of the nanoparticle-stabilized liposomes and also allowed them to be controllably released by changing the concentration of the hydrogel crosslinker. Using Staphylococcus aureus bacteria as a model, the researchers showed that, once released from the hydrogel, the liposomes could fuse with the bacterial membrane in a pH-dependent manner, with a more acidic environment increasing the fusion activity.

When Gao and colleagues tested their hydrogel formulation on the skin of mice, they observed no toxicity or adverse reactions, with the hydrogel-treated skin displaying the same good health as the control after seven days of application.