Catch and release strategy of matrix metalloprotease aptamers via thiol–disulfide exchange reaction on a graphene based electrochemical sensor

Abstract

Matrix metalloproteases (MMP) are a large family of proteases, which synergistically degrade abundant extracellular matrix and play an essential role in tissue degradation and remodelling. Sensing of MMP levels, notably the pro- and activated matrix metalloproteinases (MMP-2 and MMP-9), would provide an early warning system of chronic inflammation in acute wounds. With this in mind, we developed a graphene-based electrochemical sensor for both of these relevant biomarkers using an innovative surface ligand, 1-pyrene pyridyl disulphide (PDS), engineered to not only capture the analyte with high affinity, but also to allow the regeneration of the whole ligand/analyte construct. The thiol–pyridyl disulphide exchange reaction was used in this work for sequential analysis of MMP-9 and MMP-2 via the engineered 1-pyrene pyridyl disulphide, the PDS surface ligand. The sensor was operational down to 0.1 pM (9.2 pg mL⁻¹) for MMP-9 and allowed to sense MMP-2 on the same surface with a detection limit of 100 pM (950 pg mL⁻¹) once treated with 1-pyrene pyridyl disulphide (PDS) (DTT) and 2-dipyridylsulfide (DPDS), followed by integration of the thiolated MMP-2 aptamer onto the PDS-modified renewable electrode interface. Using swab samples from diabetic patients with open wounds confirmed that the sensors characteristics are adapted for sensing of MMP levels in wound fluids and will open up the future for the development of intelligent bandage.