Reagent-free ultrasensitive spectroscopic probes for long term diabetes monitoring

Long-term glycemic control is essential in developing therapeutics for diabetics. Glycated hemoglobin (HbA1c) and glycated albumin have been increasingly accepted as a functional metric of glycemic control over the past two to three months and three weeks, respectively. In this talk, we present the first demonstration of non-enhanced Raman spectroscopy as a novel analytical method for quantitative detection of HbA1c and glycated albumin. Using the drop coating deposition Raman technique, we observe that the non-enzymatic glycosylation of these proteins results in subtle, but consistent, changes in vibrational features, which with the help of multivariate classification techniques can be used to discriminate the glycated proteins from their unglycated variants with 100\%. Additionally, the developed multivariate calibration models show a high degree of prediction accuracy even at substantially lower concentrations than those typically encountered in clinical practice. The excellent accuracy and reproducibility achieved in this proof-of-concept study opens substantive avenues for basic investigations of glycated proteins as well as in high-throughput glycemic marker sensing in multi-component mixtures and potentially even in serum and whole blood samples.