Study On The Preparation Of A New Type Of Oxygen Lipid Microbubble And Its Vitro Experiments

Objective: To optimize the proportion of O2and C3F8, build stableand efficient lipid oxygen carrying micro bubble (LOM), and evaluate itsphysical and chemical properties.Methods: LOMs were prepared with the DSPC+DPPE-MPEG5000as theshell and the O2+C3F8as the core, which were divided into six types basedon the proportion of O2+C3F8(that is0:1,1:0,1:1,3:1,5:1and10:1). Thecharacterization and physical properties (shape, concentration, size) of eachgroup of LOMs were observed under light microscopy and zetasizer3000HS at3h,1day,3day and7day after preparation of LOMs; Theoxygen release kinetics of LOMs in the severe hypoxia solution(DO=0.4mg/l) were monitored by dissolved oxygen meter (HQ30D) at0.5h,3.0h and1d after preparation of LOMs. Selected the optimized proportion of O2+C3F8,its Zeta surface Potential and PH value within7days were detected;after60co irradiation,the morphology, size,concentration, Zeta surface Potential and the ability to release oxygen ofthe optimized LOM was also observed. Moreover，toxic effects of theoptimized LOM were investigated in cultured anoxic fetal rat hippocampalneurons and determined by MTT colorimetric assay, in which theexperiment were divided into four groups:(1) LOM with hypoxic,(2)control,(3)triton-x100,(4)normal group without hypoxic.Results: Among the six type LOMs, LOM5:1was optimal, whichhad spherical shape, narrow size distribution and high concentration. Theaverage particle size was about (959.7±161.2) nm, the concentration wasabout (4.01±0.69)×109/ml, the Zeta surface potential was about-(12.9±2.4).The physical properties didn’t change7d after their preparation(p>0.05). LOM5:1can release oxygen efficiently in the severe hypoxicsolution (DO=0.4mg/l), which made the DO of the solution increaseabout12times. Moreover, it can release oxygen stably within24h. After60co irradiation, the shape, size, concentration, Zeta surface potential andthe ability to release oxygen of LOM5:1had no obviously change (p>0.05).The optical density values of cells between the first group and the forthgroup had no significant difference (p>0.05), but there was a significantdifference to compare with other two groups (p<0.05).Conclusion: LOM5:1had a most stable performance and a best capacity of carrying and releasing oxygen. In addition, the LOM5:1had notoxic effect on cell lines. Objective: To study the effect of Ultrasound (US) on oxygen releasefrom LOM5:1in the moderate hypoxic solution, detect the Po2of thehuman venous blood in vitro after added the LOM5:1,and observe the USimaging of LOM5:1.Methods: After the preparation of LOM5:1, a series of experimentswere carried out to investigate the oxygen release kinetics in moderatehypoxia solutions(DO=4.0mg/l) in the presence or in the absence of US,and test the blood oxygenation of venous blood in vitro after mixing withLOM5:1. The enhancement effect of ultrasound imaging on rabbit liverwas evaluated after the micro bubble injection.Results: LOM5:1can increase the DO of moderate hypoxia solutionabout0.5times, compared with the preliminary experiment research thatthe DO of the extreme hypoxia solution were increased about12times,LOM5:1was able to release more oxygen in the extreme hypoxic solutions in vitro. The oxygen release kinetics could be enhanced after insonationwith US at3.5W,1.0KHz（P<0.05）. LOM5:1can improve the Po2ofhuman venous blood in vitro effectively（P<0.05）. The ultrasound imagingon rabbit liver was greatly enhanced after LOM5:1injection, and lasted for30min.Conclusion: LOM5:1can effectively released oxygen in extremehypoxia solution, released more oxygen with US, and remarkably increasedthe Po2of venous blood in vitro. In addition, it can be a novel and idealultrasound contrast agent.