Glucose sensing in oral mucosa simulating phantom using differential absorption based frequency domain low-coherence interferometry

The superluminescent diode based differential absorption frequency domain low-coherence interferometry (FD-DALCI) technique is proposed and demonstrated for sensing physiological concentrations of glucose (0–250 mg/dl) in oral mucosa simulating phantoms (intralipid of concentrations 0.25–0.50%) with wavelengths at 1589 and 1310 nm. The proposed technique allows simultaneous measurements of refractive index based spectral shift and estimation of physiological concentration of glucose in intralipid with scattering characteristics using the differential absorption approach. The sensitivity of the glucose concentration obtained by spectral shift measurement was ≈0.016 nm∕mg∕dl, irrespective of the intralipid concentration. The resolution of the glucose level was estimated to be ≈15 mg∕dl in 0.25% intralipid and ≈19 mg∕dl in 0.5% intralipid using the FD-DALCI technique.