A universal distance-independent ratiometric electrochemical biosensing strategy based on competitive host-guest interactions for matrix metalloproteinase-2 detection

Abstract

A versatile and universal distance-independent ratiometric electrochemical biosensing strategy was developed for accurate and sensitive determination of matrix metalloproteinase-2 (MMP-2). The universal ratiometric biosensing surface with excellent electrocatalytic activity and dual signal output mode was successfully constructed through the electrodeposition of β-CD on PtGa nanorods decorated graphene oxide modified electrode surface and using bisphenol A (BPA) and rhodamine B (RhB) as ratiometric probes. The target MMP-2 could trigger the release of phospholipase A2 from the as prepared multi-functionalized magnetic bead to release a large amount of BPA encapsulated with liposome and realize “one-to-many” amplification. Based on the competitive host-guest interactions, the released BPA could replace RhB, which results in the peak current of RhB (IRhB) decreased and the peak current of BPA (IBPA) appeared correspondingly. As a result, the IBPA/IRhB can be used to accurately reflect the original level of MMP-2. Accordingly, the biosensor exhibited a wide linear detection range from 0.1 fg/mL to 0.1 ng/mL with a detection limit of 36.57 ag/mL for MMP-2. This work opens a promising avenue to develop the distance-independent ratiometric biosensing system and provide favorable expansibility for the universal detection of biomolecules.