Secondary Logo

Journal Logo

Institutional members access full text with Ovid®

Ultrasound Enhances Gene Expression of Liposomal Transfection

UNGER, EVAN C. MD*; McCREERY, THOMAS P. MsC*; SWEITZER, ROBERT H. BSc*

Original Investigations
Buy

RATIONALE AND OBJECTIVES Cationic liposomes are under development as delivery agents for gene therapy. The authors studied the effect of ultrasound on gene expression in cell cultures during liposomal transfection experiments.

METHODS Cationic liposomes of dipalmitoylethylphosphocholine and dioleoylphosphatidylethanolamine were used to transfect cultured HeLa, NIH/3T3, and C127I cells with the chloramphenicol acetyl transferase (CAT) gene. A cell viability assay was performed on cultured HeLa cells that were exposed to varying durations (5 seconds or 30 seconds) and intensities of 1 MHz continuous-wave therapeutic ultrasound after transfection, and gene expression was measured 48 hours later.

RESULTS Cells survived 30 seconds or less at a power level of 0.5 watts/cm2 but died when exposed for 60 seconds or longer. Exposures of 5 seconds and 30 seconds of ultrasound resulted in significant increases in gene expression in all three cell types tested in this experiment.

CONCLUSIONS Relatively low levels of ultrasound energy can be used to enhance gene expression from liposomal transfection. Additional experiments are needed to optimize this process and clarify the mechanisms involved.

From ImaPx Pharmaceutical Corporation, Tucson, Arizona.

Reprint requests: Evan C. Unger, MD, ImaRx Pharmaceutical Corporation, 1635 East 18th St., Tucson, AZ 85719.

Received February 13, 1997, and accepted for publication, after revision, April 15, 1997.

© Lippincott-Raven Publishers