Electroporation is the critical step in an electric field mediated drug or gene delivery protocol. Electroporation based protocols have been successfully demonstrated in cancer clinical trials, however, its impact in other applications is still under investigation. A significant roadblock to long term functioning of implantable biosensors in vivo is the tissue reaction in the form of fibrous encapsulation that results in reduced transport to the sensing element of the biosensor. In vivo gene electroporation has a great potential as a means to modify the transport properties of tissues in the proximity of the sensing element of implantable biosensors. This dissertation examines two postulated electroporation based strategies to modify tissue for enhanced performance of an implantable biosensor. In the first, the implantation protocol is modified to accommodate in vivo electroporation. In the second strategy, the the modification is applied post implantation. This post-implantation in vivo electroporation application requires that electric energy be delivered at the site of electroporation close to the biosensor while minimizing effects far from such site. A novel method, focusing electric fields, developed for this purpose is presented. A theoretical framework as well as in vitro and in vivo experiments are provided as the introduction to the method and in support of its potential as the basis of a viable technology.