Unlike non-invasive and minimally invasive continuous monitoring of glucose (CGM) devices, invasive devices require less rigorous calibration and exhibit smaller subject-to-subject variability. Biorasis, Inc. and the University of Connecticut are developing a totally implantable CGM device. Glucowizzard™ is engineered at the smallest possible footprint (0.5 × 0.5 × 5 mm). This miniaturization is made possible by utilizing light both for powering and wireless communication. In addition, Glucowizzard™ utilizes 'smart' hydrogel coatings intended for localized release of various tissue response modifiers for effective control of negative tissue responses. The use of light-based powering and communication together with advanced microelectronic design rules has allowed the fabrication of truly miniaturized CGM device. The drug delivery coating has enabled substantial reduction of negative tissue responses for up to 1 month in small as well as large animals (rats and minipigs). The functionality of Glucowizzard™ has been demonstrated in vivo in both rats and minipigs.