Preparation and characterization of luteinising-hormone releasing hormone nanoliposomal microbubbles specifically targeting ovarian cancer cells in vitro.

The aim of the present study was to prepare luteinizing-hormone releasing hormone (LHRH) nanoliposomal microbubbles specifically targeting ovarian cancer cells. The lyophilization/sonication method was used to prepare non-targeting nanoliposomal microbubbles (N-N-Mbs). Using the biotin-avidin bridge method, conjugated LHRH antibodies to N-N-Mbs generated LHRH nanoliposomal microbubbles (LHRH-N-Mbs) specifically targeting ovarian cancer cells. The morphology and physicochemical properties of the microbubbles was detected using an optical microscope and zeta detector. The binding affinity between the secondary antibody and LHRH-N-Mbs or N-N-Mbs was determined by flow cytometry. The binding of LHRH-N-Mb to human ovarian cancer cells (OVCAR-3) was detected by light microscopy. The rounded and uniformly distributed N-N-Mbs and LHRH-N-Mbs were successfully generated. The particle size ranged from 295-468 nm with a mean of 360 nm for N-N-Mbs or 369-618 nm with a mean of 508 nm for LHRH-N-Mbs. There was a significant difference in size between the two groups (P<0.05), although the surface potential of the two microbubbles remained the same (-14.6 mV). Following being kept at room temperature for 14 days, no significant difference in the physicochemical properties of the LHRH-N-Mbs was detected compared with that of freshly prepared microbubbles. The secondary antibody binding rate of LHRH-N-Mbs and N-N-Mbs was 75.6 and 0.83%, respectively. Furthermore, the formation of a rosette-like structure surrounding OVCAR-3 cells was observed after the cells were incubated with LHRH-N-Mbs, whereas pre-incubation with LHRH antibody blocked this rosette formation. In conclusion, LHRH-N-Mbs specifically targeting ovarian cancer cells were successfully prepared through biotin-avidin mediation and the lyophilization/sonication method. The key feature of LHRH-N-Mbs is their small size, stability and high efficiency in targeting human OVCAR-3 cells in vitro.