A cost-effective and sensitive photothermal biosensor for the diagnosis of diabetes based on quantifying the sialic acid content on erythrocytes

Photothermal sensors represent a novel type of probe having potential in the field of clinical diagnostics particularly due to the lack of a tedious sample pre-treatment, a sophisticated equipment and a skilled manpower. Herein, we describe the fabrication of a microfluidic nickel-resistive temperature detector (micro-Ni-RTD) for the selective monitoring of diabetes using a boronate-based sialic acid (SA) receptor. This work represents an improvement made to our previous photothermal sensor designs by reducing the cost by about 100-fold and significantly improving the sensitivity of the device, enabling the detection of sialic acid contents as low as 0.06 μmol/mL, a 4-fold improvement compared to the sensor described our previous study. The average temperature difference between healthy subjects and diabetes patients was found to be 0.181 °C dL/g with micro-Ni-RTD in comparison with 0.043 °C dL/g with our previous platinum-based resistive temperature detector (Pt-RTD) reported previously The enhancement in the discriminatory ability of micro-Ni-RTD for the diabetic clinical samples compared with healthy control can be attributed to the modified surface modification strategy and the incorporation of the microfluidic channels. Thus, micro-Ni-RTD represents a convenient, rapid, reliable, and low-cost biosensor for the clinical monitoring of diabetes patients.