Electrogenerated chemiluminescence biosensor for assay of matrix metalloproteinase-14 and protein-expressing cancer cells via inhibitory peptides-based sandwich assay

• A sandwich electrogenerated chemiluminescence biosensor was firstly developed for determination of matrix metalloproteinase; • Non-specific adsorption due to cleavage is avoided; • Sensitivity is enhanced since sandwich mode provide zero signal background; • The detection of MMPs is more specialized since one MMP identified by the two peptides. A novel electrogenerated chemiluminescence (ECL) biosensor based on sandwich structure between target and inhibitory peptides was firstly developed for determination of matrix metalloproteinase and its expressing cancer cells. Here, target MMP-14 was used as model protein. Inhibitory peptide (AP1) was used as capture probe. Ruthenium complex (Ru) tagged inhibitory peptide (AP2) was used as signal probe (Ru-AP2) in this work. The biosensors were fabricated by covalently coupling Cys group of AP1 onto the surface of functional fullerene-chitosan (C60-Chit) nanocomposite modified glassy carbon electrode. Upon binding of MMP-14, Ru-AP2 further specially bound to MMP-14 and a sandwich format formed, and increasing ECL signal was obtained. Under the optimal experimental conditions, the designed biosensor exhibited excellent sensitivity with a wide linear range of 0.05−7 pg mL -1 and a detection limit of 0.008 pg mL -1 . The biosensor is demonstrated by detecting of living cells expressing MMPs (MDA-MB-231 cancer cells as model) and distinguish the expression MMPs in different cells. Our work firstly fabricated a sandwich ECL biosensor for determination of MMPs and MMPs relative cancer cells based on the interaction between peptide inhibitors and PEX of MMPs, which will provide a platform to study the mechanism of MMP and inhibitors.