Nanocomposite Microcontainers with High Ultrasound Sensitivity

Abstract

A water suspension of nanocomposite microcapsules with embedded ZnO nanoparticles in the capsule shell is reported. The microcapsule morphology is characterized by confocal microscopy, TEM, SEM, and AFM before and after ultrasound treatment. A remarkably high capsule sensitivity to ultrasound is evidenced, and it is observed to grow with increasing number of ZnO nanoparticle layers in the nanocomposite shell. This effect is correlated with the mechanical properties of microcapsules measured with AFM.

Nanodeformations of microcapsules: comparing the effects of cross-linking and nanoparticles

“…A weak increase in the Young’s modulus observed for the highest number of ZnO layers can be explained by the attainment of high “critical” concentration of nanoparticles in the shell, at which the interactions between them can contribute to the shell stiffness. 30 The reported results 29 are, on the first glance, quite comparable with our findings. However, this apparent analogy should be treated with caution, taking into account the specific layer-by-layer morphology of the polyelectrolyte microcapsules as well as the high error limits for the data given in ref.…”

Theranostic Multilayer Capsules for Ultrasound Imaging and Guided Drug Delivery

“…Our results demonstrate that US at 14 W/cm 2 for 20 s (280 J/cm 2 total energy delivered over the treatment time) was enough to rupture and deform (TA/PVPON-58) 8 capsules. In contrast, much higher intensity (280 W/cm 2 ) was required to break ionically paired nanoparticle-free PSS/PAH multilayer capsules. ,, In our work, only 1120 J/cm 2 was applied total to not only disrupt capsules but also release the drug, while 14841 J/cm 2 was needed to release 35% of the encapsulated protein from (PSS/PAH) 4 capsules …”

Impact of high-frequency ultrasound on nanocomposite microcapsules: in silico and in situ visualization

“…Nevertheless, the average shell thickness for the nanocomposite microcapsules was higher than the previously reported value. 39 It can be caused by using a different ultrasound power for the ZnO colloid pretreatment which was 600 W in previous work 39 and 200 W in our experiment. This can provide a large difference in the size distribution of the nanoparticle aggregates in a colloid.…”

“…The characteristic thick folds were observed on the microcapsule shell with ZnO layers. Even though our experimental data cannot be directly compared with previous work 39 because we used larger ZnO nanoparticles and a lower power for the ultrasound pretreatment of the ZnO nanoparticles, there are solid reasons to presume that the main differences in the microcapsule shell properties are caused by using different solvents to remove the template core.…”