Detecting disease biomarkers or analytes and quantifying minute changes in their concentrations in bodily fluids, in the living tissue or at single cell level is one of the biggest endeavors of the biomedical engineers. We tackle this challenge by integrating biofunctionalized mixed conductors in customized electronic devices so that they have high sensitivity, specificity and speed. Our work includes designing biosensors in the form of wearable or in vitro devices fabricated using inkjet printing or micronscale implantable probes developed using photolithography. Focusing mostly on electron transporting polymers, we currently build sensors that detect metabolites and cations in a variety of ex-vivo environments. On the other hand, we know that all electronic devices require a power source to operate. While developing efficient sensors is a part of the microelectronics revolution, next generation biosensors need to be self-powered to eliminate an external power supply and bulky wires. Our second research effort therefore aims to develop polymer-based power generators in line with these sensors.