Microencapsulated bio-markers for assessment of stress conditions in aquatic organisms in vivo

Bio-compatible polyelectrolyte sub-micron micro-capsules have been developed and applied to deliver fluorescent dyes into zebrafish larvae heart via direct injection in pericardium in vivo . The capsules shell performed as a membrane is impermeable for florescence dyes suspended within the capsules and is permeable for the external environment. Thus, the direct contact of fluorescence dyes with cells/tissues is excluded and the issues associated with the toxicity of fluorescence dyes and their bio-compatibility can be omitted. The hybrid laser-scanning imaging system combined with the fluorescent microscope has been used to monitor the paths of micro-capsules within zebrafish circulation system. We demonstrate that micro-capsules circulate in tissues, including brain and trunk, with no blood flow disruptions or any other deleterious effect on its cardiac function. The developed approach has a great potential to use of encapsulated bio-markers as a diagnostic tool in vascular biology and medicine as well as for monitoring of aquatic pollution and ecological risk assessment in eco-toxicological studies.