Picomolar detection of retinol binding protein 4 for early management of type II diabetes.

Type (II) diabetes is one of the major threats to mankind as it causes insulin resistance in human body and Retinol Binding Protein 4 (RBP4) is currently considered as a potential biomarker for early management of this disease. Hence a low-level detection of RBP4 is a very important task and for this purpose, a novel RBP4 biosensor has been developed using homemade plastic chip electrodes (PCEs) as a platform for self-assembled monolayer (SAM) of 4-ATP and further functionalization with glutaraldehyde. Anti RBP4 is used as biorecognition species and electrochemical impedance spectroscopy has been performed to detect different RBP4 concentrations plotted against charge transfer resistance. A wide concentration range from 100 fg/mL to 1 ng/mL has been tested and a low limit of detection (LOD) of 100 fg/mL has been achieved. This is the first report for fabrication of electrochemical biosensor of RBP4 using Ag-Ab interaction having such low LOD. The sensor is characterized by various physico-chemical techniques. Excellent reproducibility and quick measurement make this biosensor extremely useful for the biomedical industry.