Abstract: Site specific therapy has emerged as a potential medical cancer treatment in recent years. The idea is to deliver high concentration drug directly and accurately to treat a specific organ locally so that patients can avoid side effects from the dose elevations associated with oral or intravenous administration. A drug carrier device is usually implanted in the patient, and for the prolong usage, polymeric coatings on top of the drug layer are commonly used as a control release agent. Although such mechanism provides a continuous and constant drug flux, clinical effects of the drug after device implantation are only available by external tests to ensure the drug effectiveness. To address these problems, we aim to create smart drug release devices, which compose of detection, control release, and communication parts, so that one can not only monitor clinical changes in patients but also control the drug flux using the same device.
Recent advances in digital inkjet technology, or so-called drop-on-demand method (DOD), have shown its capability of creating bio-sensors to detect trace amount of chemicals. Same technology has also been used to make polymeric coatings for drug release devices, and to print micro-circuitry, such as RFID, to communicate with external electronic devices. With the combination of these printed parts, a drug release device with wireless communication functions can be assembled with merely an inkjet printer. Moreover, DOD method provides micro-patterning in a large scale at low price with great flexibility for customization to meet patients’ needs. Hence, applying DOD technology on medical device production is technically feasible and financially profitable.
In order to flawlessly integrate printed components and to accelerate the design process, computational fluid dynamics (CFD) combining with molecular simulations will be used to optimize device performance. Screening of biosensor designs will be guided by molecular simulations to enhance the sensitivities of biosensors to the environmental changes, such as drug molecules binding to proteins. Computer simulations for convective diffusion and adsorption of drug molecules in blood streams will be conducted to understand the effects of drug location and polymer layer thickness on release rates. With the help of similar simulations, we will also design micro-depots in the device as reservoirs to increase drug storage and to facilitate drug delivery. Printed electronics, which is connected to the bio-sensors, will then embed in the polymer coating to provide information collection and/or communication devices.
In summary, we suggest using drop-on-demand (DOD) technology for the production of smart drug delivery devices, which are accompanied with bio-sensors to detect clinical environmental changes and remote communication circuits to monitor or control drug release rate externally. We will perform state-of-art design process with the help of computational fluid mechanics and molecular simulations to optimize device performance. Academic studies on the sensitivity of bio-sensors, effectiveness of wireless circuitry, and drug release control mechanisms will inspire numerous ideas for publications. Muti-disciplinary collaboration with other departments in NTU and other world-renown institutes is currently undergoing. We believe that this research will generate a new industrial discipline for medical device production.