Biologic design criteria for implantable electrochemical devices

The lack of knowledge of biological interactions at the interface between material and tissue has been a major impediment to the development of functional implantable devices, including controlled drug delivery and metabolite sensing. Specifically, there is a need to generate a database of realistic biological design criteria of prototype electrochemically based (anode/cathode) drug delivery systems for cancer therapy and glucose sensing applications. While employing the same mechanism, the prototypes under study differ in the choice of the component materials. The micro-electronic mechanical (MEMS) drug delivery system is produced by a silicon-based microfabrication technique. In contrast, the glucose bio-sensor uses thick film processing technology where a printing medium is set on a polymeric substrate. The nature of the applications demands good biocompatibility and reduced biofouling. These devices should not induce any adverse effect on the biological environment (biocompatibility), while the surrounding tissues should not impede on the devices' long-term functionality (biofouling). This work investigated, in a quantitative manner, the in vivo inflammatory and wound healing response, and performance of functional electrochemical devices. Such resource will help determine the necessary design criteria, based on biologic interactions, leading to material selection and improved performance of in vivo controlled release and bio-sensing devices.