In vivo evaluation of a chip based near infrared sensor for continuous glucose monitoring

In this paper we describe the concept and in vivo results of a minimally invasive, chip-based near infrared (NIR) sensor, combined with microdialysis, for continuous glucose monitoring. The sensor principle is based on difference absorption spectroscopy in selected wavelength bands of the near infrared spectrum (1300 nm, 1450 nm, and 1550 nm) in the 1st overtone band. In vitro measurements revealed a linear relationship between glucose concentration and the integrated difference spectroscopy signal with a coefficient of determination of 99% in the concentration range of 0-400mg/dl. The absolute error in this case is about 5mg/dl, corresponding to a relative error of about 5% for glucose concentrations larger than 50mg/dl and about 12% in the hypoglycemic range (