Strain-Controlled Release of Molecules from Arrayed Microcapsules Supported on an Elastomer Substrate

摘要

Over the last two decades, considerable attention has been paid to the controlled release of drugs. Most studies have focused on sustained release from a variety of drug-containing carriers. However, there are many clinical situations that require more than a prolonged, continuous release of drugs. For example, chronopharmacological studies indicate clear temporal or physical dependence of the onset of certain diseases on circadian rhythms. The treatment of such diseases would benefit from smart control over the release pattern of a drug in response to in vivo physiological changes or external stimulations. A fast response of the drug carrier to the stimuli may enable real-time control of the dosage. The concept of stimuli-regulated release has been studied for changes in the pH value or temperature, ultrasound, and electric or magnetic fields, but has not been applied to mechanical strain, although this stimulus is ubiquitous in the body or very simple to apply externally. Strain changes are involved in many processes, such as compression in cartilage and bones, tension in muscles and tendons, and shear force in blood vessels. Strain-controlled release, if possible, could be applied in patches that respond to body motions, without the need for continuous release in vain. It would also be useful for implanted patches that could synchronize with the mechanical motions of organs, muscles, and tendons.