Abstract
Ultrasound insonification of microbubbles can locally enhance drug delivery by increasing the cell membrane permeability. To aid development of a safe and effective therapeutic microbubble, more insight into the microbubble-cell interaction is needed. In this in vitro study we aimed to investigate the initial 3D morphology of the endothelial cell membrane adjacent to individual microbubbles (n = 301), determine whether this morphology was affected upon binding and by the type of ligand on the microbubble, and study its influence on microbubble oscillation and the drug delivery outcome. High-resolution 3D confocal microscopy revealed that targeted microbubbles were internalized by endothelial cells, while this was not the case for non-targeted or IgG1-κ control microbubbles. The extent of internalization was ligand-dependent, since αvβ3-targeted microbubbles were significantly more internalized than CD31-targeted microbubbles. Ultra-high-speed imaging (~17 Mfps) in combination with high-resolution confocal microscopy (n = 246) showed that microbubble internalization resulted in a damped microbubble oscillation upon ultrasound insonification (2 MHz, 200 kPa peak negative pressure, 10 cycles). Despite damped oscillation, the cell's susceptibility to sonoporation (as indicated by PI uptake) was increased for internalized microbubbles. Monitoring cell membrane integrity (n = 230) showed the formation of either a pore, for intracellular delivery, or a tunnel (i.e. transcellular perforation), for transcellular delivery. Internalized microbubbles caused fewer transcellular perforations and smaller pore areas than non-internalized microbubbles. In conclusion, studying microbubble-mediated drug delivery using a state-of-the-art imaging system revealed receptor-mediated microbubble internalization and its effect on microbubble oscillation and resulting membrane perforation by pores and tunnels.
| Original language | English |
|---|---|
| Pages (from-to) | 460-475 |
| Number of pages | 16 |
| Journal | Journal of Controlled Release |
| Volume | 347 |
| DOIs | |
| Publication status | Published - Jul 2022 |
Bibliographical note
Funding Information:The authors would like to thank Robert Beurskens and Frits Mastik from the Department of Biomedical Engineering and Michiel Manten from the Department of Experimental Medical Instrumentation for technical assistance, all from the Erasmus MC University Medical Center Rotterdam, the Netherlands. The authors also thank Ann Seynhaeve from the Laboratory Experimental Oncology, Department of Pathology, Erasmus MC University Medical Center Rotterdam, for the fruitful discussions. This work was funded in part by the Applied and Engineering Sciences TTW (VIDI-project 17543), part of NWO, the Phospholipid Research Center in Heidelberg, grant number KKO-2017-057/1-1, and in part by the Thorax Center of Erasmus MC University Medical Center in Rotterdam.
Funding Information:
The authors would like to thank Robert Beurskens and Frits Mastik from the Department of Biomedical Engineering and Michiel Manten from the Department of Experimental Medical Instrumentation for technical assistance, all from the Erasmus MC University Medical Center Rotterdam, the Netherlands. The authors also thank Ann Seynhaeve from the Laboratory Experimental Oncology, Department of Pathology, Erasmus MC University Medical Center Rotterdam, for the fruitful discussions. This work was funded in part by the Applied and Engineering Sciences TTW (VIDI-project 17543), part of NWO, the Phospholipid Research Center in Heidelberg, grant number KKO-2017-057/1-1, and in part by the Thorax Center of Erasmus MC University Medical Center in Rotterdam.
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© 2022 The Authors