Real-time assessment of ultrasound-mediated drug delivery using fibered confocal fluorescence microscopy.
OBJECTIVE
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).


METHODS
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.


RESULTS
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).


CONCLUSIONS
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.
Laboratory for Molecular and Functional Imaging: From Physiology to Therapy, FRE 3313-CNRS and University Bordeaux Segalen, 146, rue Léo Saignat, Case 117, 33076, Bordeaux cedex, France.
Marc
M
Derieppe
Anna
A
Yudina
Matthieu
M
Lepetit-Coiffé
Baudouin Denis
BD
de Senneville
Clemens
C
Bos
Chrit
C
Moonen
D000818:Animals; D045744:Cell Line, Tumor; D002463:Cell Membrane Permeability / Q000528:radiation effects; D016503:Drug Delivery Systems / Q000379:methods*; D006801:Humans; D007700:Kinetics; D045423:Microbubbles; D018613:Microscopy, Confocal / Q000379:methods*; D008856:Microscopy, Fluorescence / Q000379:methods*; D008954:Models, Biological; D057054:Molecular Imaging / Q000379:methods*; D009930:Organic Chemicals / Q000737:chemistry / Q000493:pharmacokinetics; D051381:Rats; D014463:Ultrasonography / Q000379:methods*
D009930:Organic Chemicals; C402795:SYTOX Green