Visualizing in vivo liposomal drug delivery in real-time.

Liposomes have tremendous potential for efficient small molecule delivery. Previous studies, however, have been hampered by an inability to monitor their distribution and release of contents. Here, the authors demonstrate the real time monitoring of small molecule delivery using luciferin as a model. To monitor the release of luciferin in vivo, luciferin was packaged in thermosensitive liposomes and delivered into transgenic mice that constitutively express luciferase. Their experiments show the thermally induced release of the liposomal content in real time. In addition, the model provides evidence that the thermosensitive liposomes are stable over a long period of time ( approximately 3 weeks), and still release their content upon heating. These data present a strategy to monitor liposomal drug delivery in vivo with luciferin.