The Ultrasound Contrast Enhancement And Mediated Cell Gene Transfection Of Self-made Liposomal Nano-bubbles In Vitro And In Vivo

Objective To observe self-made cationic nanobubbles as non-viral gene carrier totransfer green fluorescent protein reporter gene into HepG2cell in vitro.Methods Cationic nanobubbles(PNB) were prepared by sonicating liposomes、polyethylenimine and perfluoropropan. The surface potential and the size ofnanobubbles were assessed by laser particle analyzer. HepG2cells were incubatedwith DNA, nanobubbles with or without ultrasound exposure. The transfectionefficiency was evaluated by flow cytometer and the cell viability by Cell CountingKit-8.Results The mean diameter of PNB was (834.57±6.4)nm and the surface charge was (4.15±0.98)mV. The PNB-DNA complexes，which blocked by the Agarose gelelectrophoresis, could effectively transfer HepG2cells, and the ultrasound exposurecould enhance the transfection efficiency further significantly (P＜0.05).Conclusions The new PNB could effectively combine with pDNA to enhance genedelivery and ultrasound exposure could improve its efficiency further in HepG2cellin vitro. Objective To investigate the ultrasound contrast effects of self-made liposomalnano-bubbles in vitro and in vivo.Methods Lipid nano-bubbles were prepared by reverse-phase evaporation method,the size and surface potential were assessed by zeta potential analyzer.Nano-bubbles/conventional contrast agent(SonoVue) were diluted to the sameconcentrations by the weight of shell membrane or the number of bubbles, to observetheir contrast effects in vitro. The nano-bubbles/SonoVue with the same bubbleconcentration was injected into the tail vein of the hepatoma subcutaneous xenograftnude mice to observe contrast effects of the liver and subcutaneous tumor.Results The nano-scale bubble was uniformity, no significant aggregation, and withan average particle diameter of (424.46±89.32)nm, bubble concentration of（6.0～ 9.0）×10~9个/ml. In the same concentrations of the shell membrane material, self-madenano-bubbles video intensity was significantly higher than SonoVue (p＜0.01).Nano-bubbles and SonoVue showed the same contrast effects in vitro with the samebubble concentration(p＞0.05). The nano-bubble could significantly enhance contrasteffects in vitro and in the nude mice liver or xenograft tumor in contrast strength, andfurthermore with longer contrast-enhanced time comparing with SonoVue.Conclusions The self-made lipid nano-bubble showed contrast enhancement effect invitro and in vivo, and the enhancing duration was longer than the conventionalultrasound microbubble contrast agent, SonoVue, which would provide experimentaldata for tumor targeted imaging and therapy in the future.