Nanoparticle-coated polymeric microbubbles for revascularization

Nano-sized materials have been widely used in many products, such as painting materials, cosmetics, and drug cargos. Especially in biological applications, nanoparticles work as drug delivery carriers in recent decades due to their features on size and transport properties compared to drug molecules alone. Modification of nanoparticle surface, structure, and its fabrication methods has been done by researchers to improve the loading efficiency and targeting performance. However, the retention of nanoparticles on the targeted tissue is still a big challenge. After injection, drug loaded nanoparticles are rapidly washed away in the area of drug delivery due to high local velocity, which limits the drug release on the desired site. In this study, we hypothesized that the nanoparticles are able to coat over the microbubble surface spontaneously through van der Waals attraction without any chemical or electrical modification on the particle surface, where the microbubble were self-assembled by the amphiphilic polymer. Microbubbles are commonly used as ultrasound contrast agents, and the limited life time of microbubbles is the major challenge for microbubble applications. The coating of the nanoparticles enhanced the microbubbles’ stability, and at the same time, the microbubbles helped to reduce the movement of the nanoparticles. Moreover, the immobilization of nanoparticles improved the performance of nanoparticle retention and the effect of drug deliver. The results provide a new strategy of the co-existence of micro- and nano-scaled particles without the additional surface tailoring and a new research direction of the improved drug retention on targeted tissue