Efficient gene therapy with a combination of ultrasound‑targeted microbubble destruction and PEI/DNA/NLS complexes

Current strategies of gene transfection are not efficient at achieving a notable therapeutic effect. The aim of the present study was to combine ultrasound‑targeted microbubble destruction (UTMD) with a polyethylenimine/pEGFP‑N3 plasmid/nuclear localization sequence (PEI/DNA/NLS) complex gene delivery system, and evaluate the transfection efficiency of enhanced green fluorescent protein (EGFP) gene delivery to 293T cells using this system. The formation of PEI/DNA/NLS complexes and the protective effects of PEI/NLS were verified by gel electrophoresis. Solutions consisting of the plasmid alone, PEI/DNA complexes, PEI/DNA/NLS complexes, UTMD+DNA, UTMD+PEI/DNA complexes, and UTMD+PEI/DNA/NLS complexes were transduced into 293T cells via ultrasound irradiation. The expression of GFP was observed using an inverted microscope and transfection efficiency was detected by flow cytometry following 24 h incubation in vitro. Cell activity was detected using a Cell Counting kit (CCK)‑8 assay. Gel electrophoresis confirmed the formation of PEI/DNA/NLS complexes and demonstrated that PEI/NLS exhibited protective effects on plasmid integrity for a limited time. Inverted microscope observations revealed that a greater GFP signal was observed with the combined action of PEI/DNA/NLS complexes with UTMD, and flow cytometry analysis demonstrated the highest level of transfection efficiency in this group. In addition, the viability of the cells detected by CCK‑8 and treated with PEI/DNA/NLS complexes with UTMD was >80%. In conclusion, the combination of UTMD and PEI/DNA/NLS complexes was highly effective for the efficient transfection of 293T cells without causing excessive cell damage. This method may provide a novel and effective gene transduction system to be applied in clinical treatments.