Graphene Nanoplatelets-Based Aptamer Biochip for the Detection of Lipocalin-2

An electrochemical label-free aptasensor platform was developed by using amine-functionalized aptamer that was incorporated onto screen-printed carbon electrode (SPCE) modified with graphene nanoplatelets (GNPs) for the detection of lipocalin-2 (LCN-2) protein. The aptamers were covalently bound to the GNPs surface via 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS) chemistry and were used as the molecular recognition element for the target protein. Successful interaction between aptamer and LCN-2 protein was ascertained via electrochemical probe, ferro-, and ferri-cyanide {Fe(CN) 6 3-/4- } and monitored by means of square wave voltammetry (SWV) whilst layer-by-layer fabrication study was done using cyclic voltammetry (CV). The developed LCN-2 aptasensor achieved sub-picomolar detection of the protein, with the detection limit determined as 0.07 pg ml -1 , and a dynamic linear range of 0.1 to 10 pg ml -1 . Fabricated aptasensor successfully demonstrated high selectivity, stability, and reproducibility as well as displaying potential for the in vitro detection of LCN-2 in real serum samples.