Bioeffects of Transient and Low-Intensity Ultrasound on Nanoparticles for a Safe and Efficient DNA Delivery

Mei Fen Shih Chung Huang Wu

doi:10.4172/2157-7439.1000276

Mei Fen Shih Chung Huang Wu

Open Access

https://doi.org/10.4172/2157-7439.1000276

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Abstract

An important advantage of polymer-based gene delivery systems over viral transfection systems is that transient gene expression without the safety concerns can be achieved. In addition to the polymeric systems to deliver DNA, therapeutic ultrasound is potentially useful because ultrasound energy can be transmitted through the body without damaging tissues and could be applied on a restricted area where the desired DNA is to be expressed. In this study, bioeffects of ultrasound on the transfection efficiency and cytotoxicity of DNA-polymer complexes on mammalian cells (HEK-293 and COS-7 cell lines) were investigated. Polymer-DNA ratios for optimal transfection efficiency and the size of PEI/DNA or PDMAEMA/DNA complexes were found not affected by ultrasound treatment. Also, electrophoresis results indicate that the tertiary DNA structure was not influenced by ultrasound when exposed up to 10 seconds. More importantly, cationic polymer-mediated cell transfection was significantly enhanced and reached a 150% increase by using ultrasound. Cytotoxicity of HEK-293 and COS-7 cell lines was not observed after ultrasound. Therefore, these results indicate that clinical applications of ultrasound could be used as a safe and efficient method for non-viral gene delivery

Highlights

Ultrasound has evolved from being primarily used for diagnosis into treatment of diseases by delivery of drugs, proteins or nucleic acids (DNA, siRNA) to the site of diseases [1,2,3,4,5,6]
We hypothesize that the procedure would minimize cytotoxicity without compromising the increase of transfection efficiency
The COS-7 cell line was cultured in completed Dulbecco’s modified Eagle medium (DMEM) culture medium, containing 5% inactivated FBS, 1mM sodium pyruvate, 25mM Hepes, and 100U/ml penicillin-100U/ml streptomycin-100μg/ ml amphotericin

Summary

Introduction

Ultrasound has evolved from being primarily used for diagnosis into treatment of diseases (e.g. cancer) by delivery of drugs, proteins (interleukins, antibodies) or nucleic acids (DNA, siRNA) to the site of diseases [1,2,3,4,5,6]. We use a transient and low-intensity ultrasound to enhance the delivery of complexes of DNA with two polymers (PEI and PDMAEMA). We hypothesize that the procedure would minimize cytotoxicity without compromising the increase of transfection efficiency These polymer-DNA complexes are stable with sizes smaller than 0.2 μm. The COS-7 cell line was cultured in completed DMEM culture medium, containing 5% inactivated FBS (from HyClone), 1mM sodium pyruvate, 25mM Hepes (from Sigma), and 100U/ml penicillin-100U/ml streptomycin-100μg/ ml amphotericin (from Invitrogen). Both cells were cultured in an incubator (Sanyo MCO-17AIC) at 37oC and 5% CO2. A two-tailed student’s unpaired test was used to compare the mean values of two populations with respect to a significant difference in transfection efficiency and cytotoxicity (GraphPad Prism 3.0 software)

Results

Discussion

Conclusions