Application Of Nano Bubble-generating Liposomes To Enhance The Efficacy Of HIFU Ablation

PART ? STUDY ON PREPARATION OF NANO BUBBLE-GENERATING LIPOSOMES,ITS GAS PRODUCTION PERFORMANCE AND STABILITYObjectivesWith the phospholipid as the enclosure and ammonium bicarbonate solution at the core,prepare liposomes containing ammonium bicarbonate(hereinafter referred to as Lip-ABC)and study on its basic features,bubble-generating performance and in vivo/vitro stabilities.MethodsThis part consists of two sections.In the Section I,film-hydration + extrusion methods are adopted to prepare Lip-ABC emulsion,and characterize its particle size,electric potentials and other properties,and then to study the its bubble-generating property under the trigger of high-intensity focused ultrasound(HIFU).In the second part,study on Lip-ABC in vitro/vivo stability by HIFU-triggered bubble-generating and photo-acoustic imaging respectively.ResultsIn the first section,with the film-hydration + extrusion methods,successfully prepare Lip-ABC,whose particle size is 173.2±71.46 nm,and its surface electric potential is-23.2±4.88 m V.After the HIFU touch-off,The average gray-scale difference increase much higher than the control group,indicating Lip-ABC can produce gas under the trigger of HIFU.In the second section,in vitro HIFU-triggered gassing is applied to study on Lip-ABC in vitro stability.Results show that Lip-ABC can stabilize for at least 6 hours at the body temperature of 37 ?.Meanwhile,the photo-acoustic imaging experiment represents that Lip-ABC can be stable in vivo for at least 6 hours.ConclusionPrepare Lip-ABC emulsion with simple processes.The emulsion is featured by appropriate particle size and excellent uniformity,has HIFU-trigger gassing capability and good in vivo/vitro stability,laying a foundation for the further experiments.PART ? STUDY ON AMMONIUM BICARBONATE AND NANO BUBBLE-GENERATING LIPOSOMES,IMPROVING HIFU EFFICIENCY FOR ABLATING BOVINE LIVER IN VITROObjectivesStudy on the effect of ammonium bicarbonate solution on improving HIFU efficiency to ablate bovine liver in vitro,and define appropriate parameters to study on the effect of Lip-ABC on improving HIFU efficiency of the ablation bovine liver in vitro.MethodsThe study will be divided into two parts.In the first part,HIFU ablates bovine liver in vitro under different power levels and time,compare average gray-scale difference,gray-scale change area,and volume of coagulative necrosis between experimental groups with ammonium bicarbonate solution in different concentrations and PBS-injected control group,to evaluate the effect of ammonium bicarbonate solution on increasing HIFU efficiency in vitro,and demonstrate appropriate synergistic power and time parameters.In the part two,based on the parameters drawn from the part one,the differences will be compared in average gray-scale difference,gray-scale change area,and volume of coagulative necrosis among Lip-ABC emulsion group,PBS solution control group and Lip-PBS(liposomes containing PBS)emulsion control group,to evaluate the effect of Lip-ABC emulsion on HIFU efficiency improvement by ablating bovine livers in vitro.ResultsIn the section one,in terms of average gray-scale difference,there's no significant disparities between the groups of(210w 5s,0.025g/ml),(210w 5s,0.5g/ml),(210w 5s,0.1g/ml),(210w 5s,0.2g/ml)and their corresponding PBS control groups(P>0.05),while the other groups are all much higher than PBS control groups(P<0.05).With regards to the area of gray change region,no remarkable differences are reported between the groups of(120w 3s,0.025g/ml),(120w 3s,0.5g/ml),(120w 3s,0.1g/ml),(120w 5s,0.025g/ml),(120w 5s,0.5g/ml),(120w 5s,0.1g/ml),(180w 5s,0.1g/ml),(180w 5s,0.2g/ml),(210w 5s,0.025g/ml),(210w 5s,0.5g/ml),(210w 5s,0.1g/ml),(210w 5s,0.2g/ml)and their corresponding PBS control groups(P>0.05),while the rest groups reports much higher than the PBS control groups(P<0.05).In respect of the volume of coagulative necrosis,no signs are observed in the groups of(120w 3s,0.025g/ml),(120w 3s,0.5g/ml),(120w 3s,0.1g/ml),(120w 5s,0.025g/ml),(120w 5s,0.5g/ml),(120w 5s,0.1g/ml);the groups of(180w 5s,0.2g/ml),(210w 5s,0.5g/ml)have no significant differences with the PBS control groups(P>0.05);(210w 5s,0.1g/ml),(210w 5s,0.2g/ml)is much lower than their corresponding PBS control groups;the rest groups register higher than that of their corresponding PBS control groups(P<0.05).In the section two,no matter HIFU(180w 3s)or(180w 5s)are,Lip-ABC all outperforms PBS and Lip-PBS control groups,in terms of average gray-scale difference,gray-scale change area,and volume of coagulative necrosis(P<0.05);there's no great discrepancies between PBS and Lip-PBS control groups,in terms of average gray-scale difference,gray change area,and volume of coagulative necrosis(P>0.05).ConclusionIn the study on improved HIFU by ammonium bicarbonate solution and Lip-ABC emulsion to ablate bovine liver in vitro,it can be concluded that Lip-ABC emulsion produce a sound track record of improving HIFU efficiency to ablate bovine liver in vitro,to ground for the further in vivo experiments.PART ? STUDY ON NANO BUBBLE-GENERATING LIPOSOMES IMPROVING HIFU EFFICIENCY FOR CUREING IMPLANTED BREAST CANCER OF NUDE MICEObjectivesStudy on the effect of intravenous-injected Lip-ABC emulsion on improving HIFU efficiency to ablate tumors,and observe its applicable safety in vivo.MethodsFirstly,establish experimental and control groups for nude mice implanted breast cancer model.Before the experiment,inject Lip-ABC emulsion to nude mice by IOCV in the experimental groups,while Lip-PBS emulsion is injected.After HIFU treatment,compare the curing differences in different time fashions in terms of average gray-scale difference,gray-scale change area,volume of coagulative necrosis,and ultrastructure.In the experiment process,pay attention to the surviving conditions of nude mice.ResultsThe experiment groups deliver better performance than the control group,no matter in average gray-scale difference,gray-scale change area,volume of coagulative necrosis or apoptosis index in non-target area in tumor tissue(P<0.05);while PCNA expression rare in the experiment groups is much lower than that in the control group(P<0.05).After HIFU treatment,mice in the two groups survive,forage and drinking water.ConclusionLip-ABC emulsion registers outstanding performance in improving efficiency of HIFU ablating tumor in vivo,and good safety as well.It is worthwhile for the future researches.