We are developing a new method of delivering substances locally and repeatedly in the retinal vasculature under external control. This delivery system is based on encapsulating the substance in heat-sensitive liposomes, which are injected intravenously and lysed by a heat pulse delivered by a laser. The feasibility of using this system with dyes and creating a sharp dye front was tested in vitro and in vivo. The results indicate that the background fluorescence of intact liposomes is minimal but in contrast a dramatic increase in fluorescence is achieved where the dye is released. In vivo tests indicated that only the selected vascular branch fluoresced. Moreover, a sharp dye front could be obtained repeatedly and preserved over significant distances. The presence of a sharp dye front allowed measurements, in vivo, of blood velocity which correlated well (r = 0.985, P<0.001) with the average blood velocity values calculated from the known flow rate.
|Original language||English (US)|
|Number of pages||8|
|Journal||Investigative Ophthalmology and Visual Science|
|State||Published - 1989|
ASJC Scopus subject areas
- Sensory Systems
- Cellular and Molecular Neuroscience