Boronic acid Functionalized Guided Mode Resonance Sensor for HbA1c Detection

An alternative optical label-free sensor, Guided Mode Resonance (GMR), is demonstrated in this paper for detection of glycated hemoglobin (HbA1c). The GMR sensor surface is modified by cross-linking with 3-amino phenylboronic acids (3-APBA) using 3-(glycidyloxypropyl) trimethoxysilane (GOPTMS). 3-APBA provides a specific interaction with HbA1c under alkaline condition. The sensing scheme is performed by tracking a peak resonance in a reflection spectrum. That relies on changes in refractive index on the sensor’s surface. Percent of HbA1c in total hemoglobin can be estimated using a ration of resonance shift due to absorbed HbA1c and the shift from changes in a bulk refractive index of a whole blood (ΔλHbA1c/ΔλTotalHb). In the measurement, Lypochek diabetes controls having 5.1% (range: 4.6–5.6% measured by HPLC) and 9.5% (range: 8.5–10.4% measured by HPLC) HbA1c are used. The results from a resonance shift ration is linearly proportional to the measurement from the HPLC standard method with a precision of 7.71–20.77% CV. This guarantees boronate-modified GMR affinity sensor for the monitoring of glycemic status in diabetes management.