Abstract: Objective To prepare a new targeted liposome ultrasonic contrast agent with anti-KDR antibody that binds
specifically with KDR as the main receptor of VEGF and evaluate its physical characteristics, biological activity and specific
binding capability in vitro. Methods A sonicator was used to prepare the biotinylated lipid micro-bubbles (MB-B), and
biotin-avidin-mediated technique was used for attachment of anti-mouse KDR monoclonal antibody to the micro-bubble shell
to generate MB-BAB-KDR. MB-BAB-KDR was incubated with fluorescent second antibody to assess the link condition, and the
control groups were the MB-B and micro-bubbles with the antibody alone (MB-B-KDR). A parallel plate flow chamber system
was used to characterize micro-bubbles attachment efficiency to KDR Fc. Results The surface of the micro-bubbles could carry
KDR antibody through the biotin-avidin bridge and MB-BAB-KDR were spherical and well-distributed. After incubation with
the second antibody, MB-BAB-KDR could be observed to emit bright green fluorescence (Grade II) as compared with little or
weak fluorescence in the control MB-B group (Grade 0) and MB-B-KDR group (Grade I). Targeted micro-bubbles bound to
KDR Fc increased as the KDR Fc concentration increased (P<0.05). Conclusion The targeted liposome contrast agent linked
with KDR antibody by biotin-avidin bridge we prepared shows an increased binding number as the KDR Fc concentration
increases, which provides a novel approach to molecular imaging study of endometrial receptivity.