Confined catalysis of MOF-818 nanozyme and colorimetric aptasensing for cardiac troponin I

Understanding the catalytic performance of nanozymes assembled in confined environment is an interesting topic. Herein, a three-dimensional nanozyme-catalytic nanoreactor was constructed by confining MOF-818 nanozyme in the pore of macroporous tungsten trioxide (p-WO3). The catalytic activity of MOF-818 assembled in-situ for the oxidation of 3,5-Di-tert-butylcatechol (3,5-DTBC) could be regulated by changing the pore size of p-WO3. Only when being confined in the pores of p-WO3 with an appropriate pore size, MOF-818 could exhibit high affinity towards 3,5-DTBC, and excellent catalytic activity for 3,5-DTBC oxidation, the catalytic rate constant k(cat) and Michaelis constant K-m were determined to be 31.47 s(-1) and 1.42 mM, respectively, and the maximum yield of 3,5-DTBC oxidation reached 95.2%. Furthermore, the as-constructed nanozyme-catalytic nanoreactor could be designed to construct a colorimetric aptasensor for selective determining cardiac troponin I based on the enzymatic inhibition effect and the exonuclease I-assisted target recycling signal amplification, which exhibited a good linear range of 50 fg mL(-1) - 100 ng mL(-1), low detection limit of 18 fg mL(-1), and was applied for human serum analysis with RSD less than 5.2% and the recoveries ranged from 95% to 107%.

Automated summary

In this study, a three-dimensional nanozyme-catalytic nanoreactor was constructed by confining MOF-818 nanozyme in the pore of macroporous tungsten trioxide (p-WO3). The catalytic activity of the nanozyme could be regulated by changing the pore size of p-WO3, and it exhibited excellent performance for 3,5-DTBC oxidation. Moreover, the nanozyme-catalytic nanoreactor was successfully used for the construction of a colorimetric aptasensor for selective determination of cardiac troponin I.