Real-Time Assessment of Ultrasound-Mediated Drug Delivery Using Fibered Confocal Fluorescence Microscopy



Transport across the plasma membrane is a critical step of drug delivery for weakly permeable compounds with intracellular mode of action. The purpose of this study is to demonstrate real-time monitoring of ultrasound (US)-mediated cell-impermeable model drug uptake with fibered confocal fluorescence microscopy (FCFM).


An in vitro setup was designed to combine a mono-element US transducer, a cell chamber with a monolayer of tumor cells together with SonoVue microbubbles, and a FCFM system. The cell-impermeable intercalating dye, SYTOX Green, was used to monitor US-mediated uptake.


The majority of the cell population showed fluorescence signal enhancement 10 s after US onset. The mean rate constant k of signal enhancement was calculated to be 0.23 ± 0.04 min−1.


Feasibility of real-time monitoring of US-mediated intracellular delivery by FCFM has been demonstrated. The method allowed quantitative assessment of model drug uptake, holding great promise for further local drug delivery studies.

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We are grateful to Dr. J.R. Cazalets and colleagues (INCIA UMR 5287/University Bordeaux 2, France) for letting us use their cell culture facility. This study was supported by EU project SonoDrugs (FP7-NMP4-LA-2008-213706), ERC project 268906 “Sound Pharma”, and Foundation InNaBioSanté—project ULTRAFITT.

Conflict of interest

The authors declare that they have no conflict of interest.

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Correspondence to Chrit Moonen.

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Derieppe, M., Yudina, A., Lepetit-Coiffé, M. et al. Real-Time Assessment of Ultrasound-Mediated Drug Delivery Using Fibered Confocal Fluorescence Microscopy. Mol Imaging Biol 15, 3–11 (2013).

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Key Words

  • Drug delivery
  • Biological barrier
  • Plasma membrane permeabilization
  • Ultrasound bioeffects
  • Fibered confocal fluorescence microscopy
  • Pharmacokinetic parameters
  • SYTOX Green
  • US-mediated drug delivery