Objective To prepare and characterize polyelectrolyte multilayer film coated microbubbles for use as ultrasound contrast agent（UCA）and evaluate its effects in ultrasonic imaging on normal rabbit’s liver parenchyma.Methods Perfluorocarbon（PFC）-containing microbubbles（ST68-PFC）were prepared by sonication based on surfactant（Span 60 and Tween 80）.Subsequently

the resulting ST68-PFC microbubbles were coated using oppositely charged polyelectrolytes by microbubble-templated layer-by-layer self-assembly technique via electrostatic interaction.The enhancement effects in ultrasonic imaging on normal rabbit’s liver parenchyma were assessed.Results The obtained microbubbles exhibited a narrow size distribution.The polyelectrolytes were successfully assembled onto the surface of ST68-PFC microbubbles.In vivo experiment showed that polyelectrolyte multilayer film coated UCA effectively enhanced the imaging of rabbit’s liver parenchyma.Conclusions The novel microbubbles UCA coated with polyelectrolyte multilayer

when enabled more function

has no obvious difference in enhancement effects compared with the pre-modified microbubbles.The polymers with chemically active groups（such as amino group and carboxyl group）can be used as the outermost layer for attachment of targeting ligands onto microbubbles

allowing selective targeting of the microbubbles to combine with desired sites.