Peptide-based electrochemical biosensor for matrix metalloproteinase-14 and protein-overexpressing cancer cells based on analyte-induced cleavage of peptide

An electrochemical peptide-based biosensor is described for the determination of matrix metalloproteinase-14 (MMP-14). The method is base on MMP-14-induced cleavage of a specific peptide carrying a ferrocene group (CK11-Fc) placed on a gold electrode. CK11-Fc was first self-assembled on the electrode and the residual surface was blocked with 6-mercapto-1-hexanol. When MMP-14 was present, it specifically cleaves the CK11-Fc. Hence, Fc leaves the electrode and this causes a decrease of the electrochemical signal, best measured at 500 mV (vs. Ag/AgCl) in Tris buffer of pH 7.4. The signal decreases linearly in the 0.2 ng L-1 to 0.9 ng L-1 MMP-14 concentration range, and the detection limit is 0.1 ng L-1 (RSD = 5.7%). The biosensor was successfully applied to the determination of MMP-14 in overexpressed tumor cells (type MCF-7). Conceivably, the work has a wide potential by exploiting such peptide cleavage approaches to construct biosensors for MMPs.