Ultrasound-active theranostic microcapsules of antioxidant polyphenolic multilayers*

Despite the accessibility of ultrasound, the clinical potential of ultrasound-active theranostic agents has not been fully realized because it requires combining sufficient imaging contrast, high encapsulation efficiency and ultrasound-triggered release in one entity. This talk focuses on ultrasound-sensitive multilayer capsules as efficient contrast enhanced imaging agents. These capsules are composed of hydrogen-bonded polyphenol tannic acid and poly(N-vinylpyrrolidone) and capable of encapsulating and delivering the anticancer drug doxorubicin upon low-power (~100 mW/cm²)  diagnostic or high-power (>10 W/cm²) therapeutic ultrasound irradiation.  We will also discuss the capsule efficacy in modulating the redox state that can influence immune responses for prolong circulation in the blood.  The ability of this material to conjugate metalloporphyrin to further enhance immunomodulatory potential by dissipation of free radicals will be also presented. Owing to the active contrast, long circulation, customizable size, shape, composition, and precise delivery of high payload concentrations, these materials present a powerful and safe platform for imaging-guided precision drug delivery.