Ultrasound-triggered release from multilayered capsules

The use of ultrasound to trigger the release from multilayered capsules to improve the drug uptake, anti-inflammatory treatment, or medical imaging. An ultrasound wave undergoes both viscous and thermal absorption, as well as scattering. A morphological change of the capsule wall occurs due to the creation of shear forces between the successive fluid layers, which results in the disruption of the capsule membrane and release of encapsulated species. Multilayered capsules were fabricated using the LbL technique by successive coating of CaCo3 microparticles with different layers of polyelectrolytes and gold nanoparticles. Suspensions of capsules were subjected to treatment with an ultrasonic probe operating at a frequency of 20kHz to evaluate the effect of ultrasound on the integrity of the wall of the capsules. Ultrasound offers an easy and fast way of inducing release from multilayered capsules, and used in many biomedical applications.