A Simple Graphene Functionalized Electrochemical Aptasensor for the Sensitive and Selective Detection of Glycated Albumin

Glycated albumin (GA) has been previously introduced as a promising biomarker for glycemic monitoring in diabetes patients with thalassemia. In this study, a label-free graphene oxide (GO)-modified aptasensor was developed for the rapid detection of GA. The fabrication of the aptasensor was dependent on the covalent interaction of the amine-functionalized GA-specific aptamer with the carboxylic groups of GO. Square wave voltammetry (SWV) analysis was carried out for the measurement of GA-aptamer binding to their specific proteins. The peak current changes before and after incubation with GA protein were directly proportional to the concentration. The developed aptasensor exhibited a broad linearity (1–10,000 µg mL−1), a low detection limit (LOD) of 0.031 µg mL−1, and high selectivity for GA detection. In addition, the aptasensor was successfully applied to detect GA in both spiked and clinical serum samples. The comparison of the developed method with a commercial assay validated the reliability of the aptasensor for clinical application. Therefore, the newly developed aptasensor is a promising tool for GA measurements in diabetic patients with underlying thalassemia.

Performance Improvement of Residue-Free Graphene Field-Effect Transistor Using Au-Assisted Transfer Method

We report a novel graphene transfer technique for fabricating graphene field-effect transistors (FETs) that avoids detrimental organic contamination on a graphene surface. Instead of using an organic supporting film like poly(methyl methacrylate) (PMMA) for graphene transfer, Au film is directly deposited on the as-grown graphene substrate. Graphene FETs fabricated using the established organic film transfer method are easily contaminated by organic residues, while Au film protects graphene channels from these contaminants. In addition, this method can also simplify the device fabrication process, as the Au film acts as an electrode. We successfully fabricated graphene FETs with a clean surface and improved electrical properties using this Au-assisted transfer method.