A biocatalytic reticular framework via enzyme immobilization for environmental pollutant monitoring.

The growing prevalence of anthropogenic pollutants demands the advancement of environmental monitoring technologies. Biocatalytic sensing, leveraging enzymatic specificity and efficiency, offers a promising alternative, yet the structural fragility and instability of free enzymes limit its practical application. A transformative strategy involves immobilizing enzymes within engineered porous frameworks, such as metal-organic frameworks (MOFs) and covalent organic frameworks (COFs). These crystalline materials offer ultrahigh surface areas, tunable pore structures, and versatile surface chemistry, forming an ideal platform for constructing robust biohybrid sensing systems. They not only enable high enzyme loading but also establish a stabilized microenvironment that enhances enzymatic activity, stability, and reusability, while significantly improving catalytic selectivity and sensitivity. This review explores the strategic integration of enzymes with porous frameworks, detailing immobilization methodologies toward biosensing platforms. By examining their application in detecting pesticides, phenolic compounds, antibiotics, pathogens, and emerging contaminants, we highlight their potential to revolutionize environmental monitoring. Finally, we discuss current challenges and outline future directions to guide the development of sensitive, durable, and field-deployable analytical systems for sustainable environmental stewardship.