Short wave Infra Red diffuse reflectance spectroscopy for noninvasive molecular detection medical devices

Published : 15 July 2019

Diabetes is a major public health and industrial issue, with the number of diabetics worldwide estimated at 415 million. Until recently, to control their blood glucose, patients had to prick their fingertips. To avoid this inconvenience, laboratories have recently been offering minimally invasive measurement systems that can be interrogated using a smartphone. This evolution, although major, still poses many problems, such as its cost, its size, or its invasiveness, even reduced. As such, a medical optical sensor, reliable, inexpensive would represent a major breakthrough: many players in microelectronics such Apple or Google produce an effort in this direction.

In vitro, the sugar measurement can be performed by diffuse spectroscopy in the SWIR domain (wavelength range 1 – 1.7 µm). A fraction of the photons produced by an immersed light source (emitter) diffuse into the liquid and emerge from it by the interplay of multiple reflections. The sugar absorption is on a band around 1.5 µm, the fraction of light emerging and detected in this range will be as lower as the sugar concentration is high. Multispectral analysis provides realistic concentration measurements. In vivo, the results are much worse because of the heterogeneity of the biological tissues and the presence of many interferents (other absorbents). The purpose of the thesis is to remove these biases by developing a new type of optical sensor comprising on the one hand several emitters, on the other hand a plurality of detectors.

This subject concerns a candidate who must have received a physicist training with a solid module dedicated to optics / photonics, interested in a work at the interface between physics and biology.

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