Frequent measurements of blood sugar are essential for the management of diabetes. While finger pricking offers accurate measurements of blood glucose, it is a procedure that causes discomfort and risk of infection. Conversely, minimally invasive biochemical sensors based on micro-needles do not assess glucose in blood but in the interstitial fluid. While most optical sensors also detect in bulk from the interstitial fluid, a depth-gated mid-infrared optoacoustic sensor (DIROS) was recently proposed to non-invasively detect glucose concentrations in blood by means of time-gating. While DIROS was previously demonstrated only in animals, herein we present the first pilot investigation of the sensor in humans, based on a multivariate model fit to measurement data obtained from healthy volunteers (n=5) during an oral glucose tolerance test. By time-gating optoacoustic signals, i.e. selecting time points corresponding to different depths within the skin based on the ultrasound time-of-flight, we confirm in humans an improved measurement accuracy when targeting deeper skin layers, which are rich in vasculature. The results set the first milestone towards depth-dependent in-blood glucose detection in humans and highlight potential for DIROS in clinical application.

V.N. is a founder and equity owner of Maurus OY, sThesis GmbH, iThera Medical GmbH, Spear UG and I3 Inc. M.K. is an equity owner and contractor for sThesis GmbH.

DRKS00036371

The research leading to these results was funded under the European Unions Horizon 2020 and Horizon Europe research and innovation programme under grant agreement no. 862811 (RSENSE) and no. 101058111 (GLUMON).

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Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The Ethics Commission of Technical University Munich gave ethical approval for this work (2023-390-S-NP).

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All data produced in the present study are available upon reasonable request to the authors