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High intensity focused ultrasound (HIFU) is widely used in medical practice, including cancer therapy. Also this approach is promising for remote release of encapsulated drugs in various other biomedical applications where local treatment is needed. Our approach underpins the minimization of HIFU impact on possible degradation of biological tissues and expand the use of HIFU in the controlled release of encapsulated drugs. We demonstrated the efficient ultrasound-induced release of labeled protein (Cy7-BSA) from elaborated nanocomposite microcapsules in vitro an in vivo. The capsule fabrication was done using combination of recently developed freezing-induced loading (FIL) technique and Layer-by-Layer assembly (LbL) used for the preparation of complex multilayer BSA/tannic acid nanocomposite capsules sensitive to HIFU. These capsules contain NIR fluorescent Cy7-labeled BSA in the shell for tracking in vivo and the high concentration of labels inside the capsules resulted in self-quenching provides the real-time detection of the protein once it is released from the capsule. Ultrasound-induced release in vivo of Cy7-labeled BSA initially quenched by magnetite nanoparticles was confirmed by fluorescent tomography. The significant decrease of Cy7 fluorescence under HIFU treatment in vitro was found to be due to a generation of reactive oxygen species and fast dye oxidation. Our results demonstrate that adapted HIFU setup can be used for the directed release of encapsulated substances in vivo under tissue compatible NIR monitoring by fluorescent tomography., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Progress in understanding the cell biology and diseases depends on advanced imaging and labeling techniques. Here, we address this demand by exploring novel multilayered nanocomposites (MNCs) with plasmonic nanoparticles and absorbing dyes in thin nonabsorbing shells as supercontrast multimodal photoacoustic (PA) and fluorescent agents in the near‐infrared range. The proof of concept was performed with gold nanorods (GNRs) and indocyanine green (ICG) dispersed in a matrix of biodegradable polymers. We demonstrated synergetic PA effects in MNCs with the gold‐ICG interface that could not be achieved with ICG and GNRs alone. We also observed ultrasharp PA and emission peaks that could be associated with nonlinear PA and spaser effects, respectively. Low‐toxicity multimodal MNCs with unique plasmonic, thermal and acoustic properties have the potential to make a breakthrough in PA flow cytometry and near‐infrared spasers in vivo by using the synergetic interaction of plasmonic modes with a nearby absorbing medium. Progress in understanding the cell biology and progression of disease depends on advanced imaging and labeling techniques. This demand is addressed by exploring novel multilayered nanocomposites (MNCs) with plasmonic nanoparticles and adsorbing dyes in thin nonabsorbing shells as supercontrast multimodal photoacoustic (PA) and fluorescent agents in the near‐infrared range. Low‐toxicity multimodal MNCs with unique plasmonic, thermal and acoustic properties have the potential to make a breakthrough in PA flow cytometry and near‐infrared spasers in vivo by using the synergetic interaction of plasmonic modes with a nearby absorbing medium. [ABSTRACT FROM AUTHOR]