title: Enhancement effect of ultrasound-induced microbubble cavitation on branched polyethylenimine-mediated VEGF(165) transfection with varied N/P ratio.
abstract: One isoform of the vascular endothelial growth factor, VEGF(165), has been reported to be a dominant mediator and regulator of angiogenic process, which plays an important role in treating cardiovascular diseases and chronically ischemic wounds. Branched polyethylenimine (bPEI) has been widely used as a non-viral delivery vector for gene therapy. Although bPEI-mediated DNA transfection efficiency can be raised by increasing the PEI nitrogen:DNA phosphate (N/P) ratio, cytotoxicity increases as well. In this study, the enhancement effect of microbubble inertial cavitation (IC) on bPEI-mediated VEGF(165) transfection was investigated, in an effort to optimize transfection efficiency using low N/P ratios. HEK 293T cells, mixed with bPEI:VEGF(165) complexes, were exposed to 1-MHz ultrasound pulses. The results show that: (1) IC activity induced by microbubble destruction can be quantified as an IC "dose" (ICD) and will increase with increasing acoustic driving pressure; (2) larger sonoporation pores can be generated by increasing ICD; (3) the transfection efficiency can be enhanced by increasing ICD until reaching a saturation level; and (4) microbubble IC activity has less cytotoxicity than bPEI, although a combinatorial effect of microbubble IC activity and bPEI could be observed on cell viability. The results suggest that, with appropriate ultrasound parameters, it is possible to optimize bPEI-mediated VEGF transfection efficiency using relatively low N/P ratios by employing ultrasound-induced microbubble inertial cavitation.
authors.affiliation: Institute of Acoustics, Key Laboratory of Modern Acoustics (MOE), Nanjing University, Nanjing, China.
authors.forename: Chun-Bing
authors.initials: CB
authors.lastname: Zhang
authors.forename: Hui-Lin
authors.initials: HL
authors.lastname: Cao
authors.forename: Qian
authors.initials: Q
authors.lastname: Li
authors.forename: Juan
authors.initials: J
authors.lastname: Tu
authors.forename: Xiasheng
authors.initials: X
authors.lastname: Guo
authors.forename: Zheng
authors.initials: Z
authors.lastname: Liu
authors.forename: Dong
authors.initials: D
authors.lastname: Zhang
mesh_terms: D003287:Contrast Media; D004337:Drug Carriers; D045423:Microbubbles; D009584:Nitrogen / Q000032:analysis*; D010710:Phosphates / Q000032:analysis*; D011094:Polyethyleneimine / Q000737:chemistry / Q000494:pharmacology*; D013010:Sonication; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics
chemical_list: D003287:Contrast Media; D004337:Drug Carriers; D010710:Phosphates; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D011094:Polyethyleneimine; D009584:Nitrogen