Measurement of refractive index variation of physiological analytes using differential-phase OCT

We report results of a study using differential phase optical coherence tomography (DP-OCT) for measurement of variation of refractive index (n) vs. analyte concentration (C) in translucent solutions and turbid tissue phantoms. Variation of refractive index with analyte concentration (dn/dC) in aqueous solutions of glucose, calcium chloride, magnesium chloride, sodium chloride, potassium chloride, potassium bicarbonate, urea, bovine serum albumin, and bovine globulin was measured. Obtained results demonstrated: (1) dn/dC for glucose is significantly greater than that of other analytes in the physiological range; and (2) high sensitivity of DP-OCT method for measurement of analyte concentration.