Experimental Study On Preparation Of The Targeted Nanoscaie Liposome Ultrasonic Contrast Agents

Objective:Preparation of stable targeted nanoscale liposome ultrasonic contrast agents to provide the material basis for the targeted ultrasound contrast diagno-sis and treatment.Methods:1. Preparation of stable nanoscale liposome ultrasonic contrast agents:Freeze-dry-ing method was selected to prepare liposome ultrasonic contrast agents. The prepared Iiposomes are characterized by measuring the concentration, surface po-tential, size security and enchogenicity, and we will evaluate the enhancement effect of different Iiposomes through the left heart imaging study of rabbits.2. Preparation and characterization of nanoscale targetable Iiposomes:IL-8mon oclonol antibody was covalently conjugated with the prepared Iiposomes, and through the slide agglutination test and immunofluorescence experiments,we de-termined whether the coupling was successful. The prepared Iiposomes are als-ocharacterized by measuring the concentration, surface potential, size security and enchogenicity.Results:1. Optimized by single factor experiments, the best composition of wall materi-als was as follow:phosphatidylcholine (EPC):distearoyl phosphatidylcholine (DSPC):palmitic acid:cholesterol (CH)=17:60:8:15(mol). The optimization of the preparation parameters were as follows:hydration temperature of55℃and hydration time30min, ultrasound power100%, pulse ultrasound (Is/Is) time5min. Liposomes employing such parameters had homogenous shape with average particle size690±92nm, the concentration4.12×109/ml, the half-life 1.25h, Zeta potential-32.04mV, and the range of osmolality278～310mOsm/kg-H2O. Then,the liposomes were used for the imaging of the left ventricular of rabbit, after analysis by Qlab8.0software, we found that the liposomes had high echogenicity in vivo. After rehydration, the liposomes preserved in tube at room temperature for1month, were still reflective.There was no death afterin jecting the Liposomal suspension in one month.2. Proved By slide agglutination test and immunofluorescence experiments, cov-alent conjuga-tion of liposome with IL-8monoclonal antibody was successfully achieved. Co-mpared with the uncoupled liposomes, the concentration of lipos-omes in the anti-IL-8mAb coupled suspension was3.05×109/ml, slightly low-er than that in the uncoupled suspension, but the size, shape and Zeta potenti-al in both suspensions were almost identical. And the targetable liposomes also have high enchogenicity and security.Conclusion:We have successively prepared targeted liposomes with a suitable size and good in vitro stability. The liposomes showed effective contrast enhan-cing in vivo ultrasound imaging. Then, the coupled liposomes would be used for the targeted ultrasound contrast diagnosis and treatment.