Stimulus-Responsive MOF-Hydrogel Composites for Sensing Applications

Stimulus-responsive metal-organic frameworks (MOFs) are a subclass of MOFs that undergo physicochemical changes in response to external stimuli. The large surface area, tunable properties, and high porosity of MOFs and their dynamic nature of stimulus-responsiveness, making them highly effective for sensing applications. The luminescence properties of MOF-based sensors enable optical detection, making them cost-effective compared with conventional sensing techniques. MOFs can response to various stimuli; however, the practical application of these stimulus-responsive MOFs is limited by challenges such as poor processability and stability, requiring further advancements to enhance their real-world viability. Recently, the integration of stimulus-responsive MOFs into hydrogels has been extensively explored to improve their performance as sensors. This review highlights the utilization of stimulus-responsive MOF-hydrogel composites as sensors. The types of stimuli, preparation methods, and the distinct roles of both MOF and hydrogel components are discussed. The applications covered include biosensing, environmental remediation, and agricultural food safety monitoring, with target analytes spanning across heavy metals, toxic anions, volatile organic compounds, pesticides, biomolecules, and mycotoxins. Furthermore, the challenges and future prospects of stimulus-responsive MOF-hydrogel composites are evaluated, with rational design strategies proposed to guide future development.