Ultrasound Contrast Agents as Facilitator for Intracellular Transport of Drugs and Genes
C Deng*, University of Michigan, Ann Arbor, MichiganTH-C-217BCD-7 Thursday 10:30:00 AM - 12:30:00 PM Room: 217BCD
Purpose: The non-invasive feature of ultrasound applications and the unique capability of ultrasound interaction with biological systems offer a beneficial platform for innovative biomedical applications. The effective and concentrated nature of ultrasound interaction with gaseous particles, has prompted the development of microbubble-based ultrasound contrast agents to enhance ultrasound imaging capability. Particularly, microbubble ultrasound contrast agents have been exploited as a vehicle for intracellular delivery of cell impermeant drugs and genes. Ultrasound excitation of microbubbles, accompanied by rapid radial oscillation and/or collapse, has shown promise as an advantageous non-viral strategy to generate transient increase of cell membrane permeability (sonoporation), thereby allowing uptake of exogenous agents into the cell cytoplasm. However, little is known about the basic processes supporting ultrasound-induced transport into and within the cytoplasm of living cells at the single cell level. Our research aims to gain understanding of the mechanism of sonoporation and to uncover the physical, chemical, and cellular factors affecting the sonoporation process and outcome, in order to successfully develop and translate sonoporation technology for targeted, safe delivery of drugs and genes.
Methods: We developed a set of novel techniques to control microbubble cavitation in reference to single cells. We used simultaneous whole-cell patch clamp recording and fluorescence microscopy for real time monitoring of sonoporation.
Results: We obtained measurements regarding the rapid formation and resealing of ultrasound-induced membrane pores. Based on sonoporation-mediated influx of an intercalating fluorescent dye, we developed a model to measure the intracellular diffusion coefficient of cytoplasmic RNA/DNA and estimate the pore size generated during sonoporation. We demonstrated spatiotemporally controlled subcellular delivery and calcium signaling in targeted cells.
Conclusion: Through controlling of ultrasound excitation of microbubbles near single cells, we obtained results that might reveal key information of sonoporation mechanisms and processes, that can guide the development of sonoporation at as an effective and robust delivery technology.