**1. Introduction**

Vital information monitoring has become an indispensable part of the next generation healthcare technologies. Remote monitoring of the vital health information facilitates personal in-home care, reduces the cost and time of frequently going to the hospitals and minimizes the difficulties of monitoring the health of the elderly persons. Recent research on contemporary implantable and wearable sensors for monitoring various physiological parameters as well as improvement of wireless technology have led to the development of all-inclusive patient monitoring systems such as Wireless Body Area Network (WBAN) and Body Sensor Network (BSN). One of the integral parts of these networks is implantable sensor. Applications of implantable sensors include (but not limited to) monitoring of blood glucose level for diabetic patients, continuous *in vivo* monitoring of lactose in the bloodstream or tissues, pressure monitoring of blood vessels and electronic interfaces to monitor the nervous system. Moni‐ toring of physiological parameters such as pH level in tissues, glucose and lactose in blood‐ streams, heart rate and respiration rate not only improves the quality of life of the patients but also increases their lifespan. Even though astounding advancements have been made in medical electronics and instrumentation, invasive medical devices such as small lancets are still used to collect samples from human body for testing and diagnostic purposes. These devices increase the risk of infection in human body. For a diabetic patient the discrete measurements provided by the lancets are not sufficient for monitoring of blood glucose level. In order to get an idea of the blood glucose trend line, continuous monitoring of glucose level is highly desirable and minimally invasive implantable sensors are ideal fit for this application. The most important concern related to the use of implantable sensor is the health safety of the patients. The true success of an implant depends on the proper functioning of the sensor without having any adverse effect on the tissues surrounding the implant.

© 2015 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited.
