Sung-Geun Choi

Implantable drug release platforms that offer wirelessly programmable control over pharmacokinetics have potential in advanced treatment protocols for hormone imbalances, malignant cancers, diabetic conditions, and others. We present a system with this type of functionality in which the constituent materials undergo complete bioresorption to eliminate device load from the patient after completing the final stage of the release process. Here, bioresorbable polyanhydride reservoirs store drugs in defined reservoirs without leakage until wirelessly triggered valve structures open to allow release. These valves operate through an electrochemical mechanism of geometrically accelerated corrosion induced by passage of electrical current from a wireless, bioresorbable power-harvesting unit. Evaluations in cell cultures demonstrate the efficacy of this technology for the treatment of cancerous tissues by release of the drug doxorubicin. Complete in vivo studies of platforms with multiple, independently controlled release events in live-animal models illustrate capabilities for control of blood glucose levels by timed delivery of insulin.

Flexible and biodegradable electronics have emerged as a promising solution for escalating electronic waste issue caused by the rapid development of skin patch electronics. Fully biodegradable displays are essential for visualizing biological/physical/chemical/electrochemical signals measured by a wide range of skin patch electronics. Here we propose fully biodegradable electrochromic display providing low operating voltage and low power consumption. The biodegradable transparent conductive electrode was fabricated by transferring free-standing tungsten nanomesh onto poly lactic-co-glycolic acid substrate using electrospinning templating, minimizing damage to the substrate. Electrochromic layer was tungsten oxide which is biodegradable, and a ferrocyanide/ferricyanide redox agent was utilized as a counter electrode reaction to enhance operational stability in an aqueous electrolyte by reducing operating voltage and side reactions. This display successfully visualized diverse signals from various biodegradable electronics such as UV sensors and electrochemical transistors, and finally underwent eco-friendly degradation in phosphate-buffered saline or soil under mild conditions.

Drug localization, release control, and penetration into solid tissues through biological tight junctions are crucial for the treatment of localized diseases with biological barriers by maximizing therapeutic efficacy of the drug and minimizing damage to normal organs. Here, we introduce a dual-phoretic wireless drug delivery system that harnesses the physical control of ion transportation: electrophoresis for controllable release and iontophoresis for directional penetration. Adjustable, pulsatile, and repeatable drug release under biological conditions is achieved using ion diodes and Zn-based electrochemical cells. Through seamless integration with iontophoretic compartments, a fourfold improvement in delivery efficiency compared to drug diffusion, reaching the core of in vivo tumor, is verified by a 3D tomographic analysis. Fully implantable and wireless operation in a simulated 2-week therapeutic scenario results in a remarkable 50% tumor reduction from the initial volume while minimizing damage to nearby normal tissue and off-target organs such as the heart, liver, spleen, and kidney.