Development of a Rapid Sandwich Enzyme Linked Immunoassay Procedure for the Highly Sensitive Detection of Human Lipocalin-2/NGAL

A rapid sandwich enzyme linked immunoassay (ELIA) procedure was developed for the highly sensitive detection of human Lipocalin-2 (LCN2), also known as neutrophil gelatinase-associated lipocalin (NGAL). It reduced the total immunoassay duration by more than 3-fold and detected LCN2 in the pathophysiological range of 2.5-5120 pg/mL with an analytical sensitivity of 7 pg/mL, which is about 11-fold better than that of the commercially-available conventional enzyme linked immunosorbent assay (ELISA). The enhanced analytical performance of developed ELIA procedure is due to the leach-proof covalent crosslinking of anti-human LCN2 antibody to the 3- aminopropyltriethoxysilane (APTES)-functionalized microtiter plate (MTP) by 1-ethyl-3-[3- dimethylaminopropyl]carbodiimide hydrochloride. The multisubstrate-compatible ELIA procedure enables LCN2 assay on different types of polymeric substrates (inert, hydrophilic and hydrophobic) using the modified MTP format. The developed ELIA procedure can be similarly employed to develop rapid and highly sensitive immunoassays for other disease biomarkers and analytes in clinical and industrial settings.