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

Abstract

The impact of high-frequency (1.2 MHz) ultrasound with a power density of 0.33 W cm(-2) on microcapsule nanocomposite shells with embedded zinc oxide nanoparticles was investigated by exploring modeling simulations and direct visualization. For the first time the sonication effect has been monitored in situ on individual microcapsules upon exposure of their aqueous suspension to ultrasound. The stress distribution on the microcapsule shell for the impact of ultrasound with high (1.2 MHz) and low (20 kHz) frequency at two fixed intensities (0.33 and 30 W cm(-2)) has been modeled. As shown in silico and experimentally the nanocomposite microcapsules were destroyed more effectively by the action of high-frequency (1.2 MHz) ultrasound in comparison to the low frequency (20 kHz) one with the same power density.

Theranostic Multilayer Capsules for Ultrasound Imaging and Guided Drug Delivery

“…35 In one study, the release of bovine serum albumin from PSS/PAH capsules with embedded Au nanoparticles was triggered by low-intensity, high-frequency US at 3.19 W after 10 min of sonication. 36 Computational simulations by Korolovych and co-workers on multilayer capsules revealed that 75% of PSS/PAH capsules modified with ZnO nanoparticles could be successfully destroyed by only 23 mW (0.33 W/cm 2 ) US for 3 s. 37 However, the inclusion of nanoparticles complicates capsule synthesis and might challenge capsule biocompatibility and biodegradability. Very recently, in situ carbonization of dextran molecules within a (PSS/PAH) 4 shell at 160 °C has been shown to result in fluorescent carbon dots, which gave the capsules cytocompatibility, ultrasound responsiveness, reduced permeability, and good fluorescent stability.…”

Inorganic/Organic Multilayer Capsule Composition for Improved Functionality and External Triggering

“…Zinin et al calculated the natural vibrations of the specific types of bacteria. [132] The polymer/zinc oxide nanoparticle microcapsule shells were destroyed by ultrasound treatment more effectively at high-frequency ultrasound in comparison to the low-frequency one with the same power density. The natural frequencies and corresponding qualities were calculated for specific types of bacteria using data about mechanical properties and thickness of cell shell.…”

“…It leads to the highest impact of ultrasound on the hydrophobic modified surface in comprising with hydrophilic surface. [132] Nowadays, A number of new approaches for in vivo visualization and treatment using ultrasound such as HIFU [133][134][135] and PA imaging [136,137] are rapidly growing. [129] The hydrophobic surfaces were made using imprinting method, [128] but recently an original approach was demonstrated using consequently adsorption hydrophilic PE molecules and hydrophobic nanoparticles.…”

“…[19] Figure 11A,B demonstrated the collective opening of microcapsule shell as results of cavitation process. [74,132] The embedding of gold nanoparticles into microcapsule shell also resulted on decrease sensitivity of microcapsule to ultrasound treatment. Usually, a doping of microcapsule shell by inorganic nanoparticles leads to enhancement of its mechanical properties, for instance Young modulus [130] and increasing shell thickness.…”

“…The shell model of a cell takes into account Young modulus and thickness of bacteria shells and the viscosities of media inside cell (the cytoplasm) and the liquid were cell were dispersed. [132] The properties of shell material effect on the parameters characterizing the resonance phenomena. [146,147] We expect that natural frequencies will be not so far for one for different type of bacteria because the size and mechanical properties of bacteria are comparable with size and elastic properties of microcapsules.…”