3D-printed high-resolution microchannels for contrast enhanced ultrasound research

Systemically circulating microbubbles are used as contrast agents to aid both drug targeting and delivery using ultrasound. Exploiting their acoustic behaviour in small diameter vessels is critical for both applications, but the highly controlled experiments required to support this are not possible in vivo and challenging in vitro. Experimental platforms with small diameter channels (below 200 microns) are not readily available nor able to represent vascular geometries, leaving the existence and extent of microbubble-microvessel interactions incompletely defined. In this work we present a 3D-printed microchannel platform using tissue-mimicking hydrogels featuring radii down to 75 microns. We demonstrate application to study microbubble behaviour via acoustic backscatter under controlled environments in physiologically-relevant conditions.