Sensors For Medicine and Science Implanted Light-Emitting Diode

Senseonics Inc (formerly Sensors for Medicine and Science or SMSI until 2012), based in Germantown, MD,  is developing a fully implantable continuous glucose monitoring system that uses fluorescence sensing technology. Their goal is to improve accuracy, ease of use and sensor life to make glucose management better.

The implanted sensor is a light emitting diode combined with a fluorescent glucose indicating polymer encased in a biocompatible material. The biocompatible material keeps the body from rejecting the sensor. The diode interacts with the polymer and signals a change in glucose concentration by changing the light output. This detection method is said to be highly accurate because the sensor is designed to respond specifically to glucose, yet not be significantly affected by other substances at concentrations typically present in interstitial fluid. Studies have shown that ISF glucose accurately correlates with blood glucose, and therefore provides useful diagnostic measurement.

The 3mm by 16mm sensor is implanted, by a physician, subcutaneously on the upper arm or abdomen (with no skin protrusion) and lasts for six months. The transmitter is worn over the implanted sensor to activate the glucose measurement process and gather readings every few minutes. From the data, the transmitter calculates the glucose concentration and sends this to a smartphone via Bluetooth or connected to a personal computer via USB. The sensor is removed by a physician after 6 months.

Senseonics has partnered with Sagentia, Inc for their medically regulated iPhone app. Sagentia provides expertise with Bluetooth low energy connectivity between the mobile app and the CGM system. The smartphone app will provide easy access of real-time glucose measurements in a device the user already carries. The app will show the glucose value, the rate and direction of glucose change, graphical trends and alerts will sound for hypo- or hyperglycemia. The data will also be stored for later analysis. The smartphone app also allows entry of daily events such as meals (carbs), health events, etc. 

Future  Plans

Senseonics is currently conducting clinical trials. They received 150 13485 certification in February of 2013.