A novel fluorometric and colorimetric dual-mode sensor for AMI early diagnosis based on an ultrathin Fe-MOF-74 nanosheet with peroxidase mimic activity and fluorescence properties

Abstract

Background

Cardiac troponin I (cTnI) is a crucial diagnosis biomarker for acute myocardial infarction (AMI). Early accurate determination of the concentration of cTnI significantly decreases the death rate of AMI. Compared with classic methods, dual-mode sensors for cTnI determination could help reduce the false positive rate.

Result

In this work, an ultrathin Fe-MOF-74 nanosheet with fluorescence properties and peroxidase mimic activity was synthesized for the first time. Applying this nanosheet, a novel dual-mode sensor was developed to quantify cTnI in human serum. The ultrathin Fe-MOF-74 nanosheets catalyze the decomposition of hydrogen peroxide produced by glucose oxidase (GOx)-triggered enzyme-linked immunosorbent assay (ELISA) applying cTnI as an antigen target, to generate reactive oxygen species (ROS). 3,3′,5,5′-tetramethylbenzidine (TMB) can be oxidized by the generated free radicals, which simultaneously lead to the fluorescence quench of Fe-MOF-74 due to the inner filter effect (IFE). The correlation between the morphology of Fe-MOF-74 and its fluorescence intensity and peroxidase mimic activity was also investigated.

Significance

The sensors exhibited linearity with the concentration of cTnI in 10–2000 pg mL⁻¹ in both the fluorescence and visual mode with the detection limit of 6.4 pg mL⁻¹ and 8.4 pg mL⁻¹, respectively. It presenting good selectivity and anti-interference ability, can provide accurate and precise results in testing the concentration of cTnI in serum samples from patients in hospitals. It could be applied in the early diagnosis of AMI to reduce the incidence, disability, and mortality rates.