Detection of glucose in diabetic tears by using gold nanoparticles and MXene composite surface-enhanced Raman...

Diabetes has become one of the three chronic non-communicable diseases threatening human health in the world, and the detection of glucose concentration is of great importance for the prevention and treatment of diabetes. The noninvasive detection of glucose in tears has attracted interest over the past several decades, however, time-consuming, expensive equipment, and specialist technicians make tear analysis still challenging. Here, flexible surface-enhanced Raman scattering (SERS) substrates composed of gold nanoparticles (AuNPs) and two-dimensional MXene Ti₃C₂T_X nanosheets have been designed. The GMXeP (gold nanoparticles with MXene nanosheets loaded on paper) SERS substrates show good sensitivity, reproducibility, and stability, yielding an enhancement factor (EF) of 3.7 × 10⁵ at the concentration of 10^-9 M. The GMXeP SERS substrates are used to detect glucose of diabetic tears within a linear range of 1-50 μM, the lowest detection concentration is 0.39 μM and the significant correlation between tear glucose and blood glucose indicates that this method is suitable for sensitive and noninvasive detection of blood glucose.