An immunosensor for the detection of N-(carboxymethyl)lysine - a diabetic biomarker

Carboxymethyl-lysine (CML) is a well-known lysine product that strongly correlates with type 2 diabetes mellitus (T2DM), and its elevated levels are significantly associated with renal impairment and T2DM-related complications. Thus, it is imperative to quantify CML levels and recognize the onset of hyperglycemia and its consequences. In this context, the development of an electrochemical immunosensor for the rapid and ultralow-level detection of CML was attempted. The fabrication of the working electrode involves the covalent immobilization of anti-CML/EDC-NHS on the surface of a carbon quantum dot (CQD)-modified glassy carbon electrode (GCE). The immunosensor exhibited two discrete linear concentration ranges of 0.5-5.0 ng mL^-1 and 5.5-10.0 ng mL^-1, with limits of detection and quantification of 0.027 and 0.087 ng mL^-1 and 0.16 and 0.51 ng mL^-1, respectively. The observed specificity and other merits of the sensor make it suitable for testing human plasma samples.