Glucose monitoring using VCSELs
This research project aims to develop an implantable, biocompatible, optical glucose monitor, which would have a tremendous health-care benefit, providing an improved glucose-monitoring tool for diabetics. It is based on semiconductor laser sources (VCSELs) at the ideal wavelength for optical glucose sensing.
A glucose sensor, capable of continuous real-time monitoring, has been considered a "holy-grail" in clinical diagnosis and treatment of diabetes for 30 years. Diabetes is a common chronic disease that is an ever-increasing public health issue. Insulin dependent diabetes is characterized by the inability of the pancreas to control blood glucose concentration. Currently, the most common medical treatment for Type I diabetes recommends three to four daily glucose measurements, and an equivalent number of subcutaneous insulin injections. However, monitoring blood glucose concentration and insulin injection can become troublesome and patient compliance is always an issue.
One of the highly pursued topics in diabetes care has been the development of an implantable continuous glucose monitor. Many companies have attempted to commercialize implantable enzyme-based chemical sensors, or optical sensors for glucose monitoring. However, current reliable biosensor devices are restricted by their short life span of several days. Implantable electrochemical sensors suffer from degradation of the glucose sensitive enzymes, as well as bio-fouling due to protein adsorption and cell adhesion on the surface of the chemical-based sensor, thus limiting their lifetimes to only several days. Optical sensors are less susceptible to bio-fouling as the sensors do not degrade over time and light can pass through the collagen fouling, but have challenges in realizing high sensitivity detection required for the weak absorption signals. A laser, with a low noise and a high spectral power density, can aid in increasing the signal-to-noise ratio and accurate glucose measurements.