MMP-9, human matrix metalloproteinase 9, belongs to the family of zinc-dependent peptide-bond hydrolases and is involved in the degradation of the extracellular matrix (ECM). In clinics, it is well known that elevated MMP-9 serum levels are associated with cardiovascular dysfunctions, several aspects of the physiology and pathology of the central nervous system, neuropsychiatric disorders and degenerative diseases related to brain tumors, and excitotoxic/neuroinflammatory processes. Due to the large interest of diagnostics in this protein, efforts to set up sensitive methods to detect MMP-9 for early diagnosis of a number of metabolic alterations are rapidly increasing. In this panorama, biosensors could play a key role; therefore we explored for the first time the development of an aptamer-based piezoelectric biosensor for a sensitive, label free, and real time detection of MMP-9. The detecting strategy involved two different aptamers in a sandwich-like approach able to detect down to 100 pg mL(-1) (1.2 pM) of MMP-9 as detection limit in standard solution. As proof of principle, commercial serum was investigated in terms of possible interferents, their identification and role in MMP-9 detection. The estimated detection limit for MMP-9 is about 560 pg mL(-1) (6.8 pM) in untreated serum.
Keywords: Aptamer; Aptasensor; Human matrix metalloproteinase 9; Human serum; Piezoelectric biosensor.
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