Gold-silane complexed antibody immobilization on polystyrene ELISA surface for enhanced determination of matrix Metalloproteinase-9

Abstract Abdominal Aortic Aneurysm (AAA) is an enlargement with abdominal aorta, identified as the life-threatening complication, particularly with men at the age over 60. Circulating biomarkers are playing a role to diagnose AAA and matrix metalloproteinase-9 (MMP-9) was identified as the suitable biomarker for diagnosing conditions with AAA. Enzyme Linked Immunosorbent Assay (ELISA) is the standard technique to detect the target, further, a suitable surface modification on the polystyrene (PS) ELISA surface leads lowering the detection limit. Herein, a potential bimolecular immobilization strategy was introduced by complexing silane-antibody or silane-gold-antibody for the efficient determination of MMP-9 detection. Further, sandwich pattern was followed to determine MMP-9 by poly- and mono-clonal antibodies and compared. Detection limit was found as 1 pM, which is much lower than conventional ELISA (1.5 nM) and 10 pM on silane-modified PS surface. Moreover, MMP-9 was also detected in human serum at 1:35 dilution, helps to quantify the level of MMP-9 for diagnosing AAA and its associated condition.