Preparation of an OTA aptasensor based on a metal–organic framework

Abstract

A novel aptasensor for ultrasensitive and rapid detection of ochratoxin A (OTA) was developed using a metal–organic framework (MOF) as the signal unit. In this work, a MOF was utilized as the signal probe. The signal probe differs from traditional probes; the signal of the cadmium ions (Cd²⁺) from the MOF can be directly detected without acid dissolution and preconcentration, greatly simplifying the detection steps and reducing the detection time. Moreover, the MOF contains large amounts of Cd²⁺ ions, which could provide high electrochemical signals. Our report is the first time using an MOF as the electrochemical signal probe for an aptasensor application. A gold nanoparticle (Au NP)-doped molybdenum disulfide (MoS₂) nanocomposite was employed as an immobilized matrix for the sensor because of its high electronic conductivity. Under the optimized experimental conditions, an ultrasensitive aptasensor for the detection of OTA exhibited a wide linear range of 0.05–100 ng mL⁻¹ with a low detection limit (LOD) of 10 pg mL⁻¹ OTA (at 3σ). With these merits, this stable, simple, low-cost, sensitive and selective electrochemical aptasensor shows promise for applications in environmental monitoring.