MOF-based molecularly imprinted nanozyme as ratiometric fluorescence sensor for highly specific and sensitive recognition of carbaryl

An MOF-based molecularly imprinted nanozyme was designed and prepared. • The nanozyme was acted as ratiometric sensor for fluorescence detection of carbaryl. • The sensor possessed the highly selectivity and sensitivity for carbaryl recognition. • The detection mechanism of MOF based nanozyme for carbaryl was investigated. Metal-organic framework (MOF) nanozymes are widely utilized in environmental pollutant detection, but their practical application is often restricted by a lack of intrinsic selectivity. To address this challenge, we developed a molecularly imprinted polymer coated Fe-MOF nanozyme (Fe-MOF@MIP) via a metal coordination and hydrogen-bonding assembly strategy. Fe-MOF@MIP integrates the peroxidase activity of Fe-MOF core with the specific recognition capability of the carbaryl-imprinted shell. And the binding of carbaryl to the specific imprinted cavities sterically blocks the surface channels, preventing the generation of reactive oxygen species and thereby modulating the fluorescence signal. Based on this inhibition mechanism, a ratiometric fluorescence sensor was constructed for sensitive detection of carbaryl with a detection limit of 0.039 μM, accompanying with the fluorescence color changing from yellow to blue under a UV lamp. More importantly, Fe-MOF@MIP exhibited high selectivity and anti-interference ability for carbaryl detection. The sensor was successfully applied to the analysis of real water and fruit samples, demonstrating their robustness. This study provides a cost-effective and simple strategy to overcome the selectivity bottleneck of nanozymes, offering a promising platform for carbaryl monitoring. Download: Download high-res image (88KB) Download: Download full-size image