Objective:In this study,we investigated the in vitro binding capacity of β-HCG antibody targeted SonoVue(R) microbubbles to trophoblasts with distinct differentiation in order to explore the possibility of utility of targeted SonoVue(R) microbubbles imaging for early locating diagnosis of malignant trophoblastic cell disease.Methods:Three cell groups were included in the study:(1) chodocercinoma cells (poody differentiated) (JAR,n=10),(2) early gestational trophoblastic cells (ETC,n=10) and (3) late placenta trophoblastic cells (LTC,n=10).The binding efficiency of the contrast agents to the targeted cells was evaluated by counting the ring formation rate before and after rinsing with PBS.Results:The binding rate was significantly higher in JAR group 84.3±5.5% than in the ETC group 67.3±3.9% and LTC group 60.4±4.6% (P＜0.05).The binding rates of different targeted cells to the related targeted microbubble contrast agent (TMCA) before and after PBS dnse did not change significantly.The JARs group exhibited the highest binding rate of (84.3±5.5)% and (82.4±3.7)% before and after PBS rinse (P＞0.05).The binding rates of the targeted microbubbles labeled with fluorescence by FCM to JARs,ETC or LTC were 90.1%,81.5% and 69.2%,respectively (P＜0.05).Conclusion:This in vitro study demonstrated that β-HCG antibody-targeted SonoVue(R) had different binding capacities to trophoblasts with distinct degrees of differentiation.The highest binding rate occurred with the choriocarcinoma cell line JAR.There is the possibility that the β-HCG antibody-targetad strategy could improve the discriminative ability of SonoVue(R),in the locating malignant trophoblastic cells.