Functionalized Layered Double Hydroxide Nanomaterials for Optical and Electrochemical Sensing Applications

Layered double hydroxides (LDHs) are gaining significant attention in analytical chemistry and clinical research due to their exceptional properties, such as biocompatibility, large surface area, high ion exchange capacity, and tunable electrical conductivity. These features make LDHs well-suited for various applications, including optical and electrochemical detection of pollutants, heavy metals, and biomolecules. LDHs can be customized regarding their chemical composition, physical structure, and responsiveness to external stimuli. This functionalization enhances sensor performance by improving sensitivity, selectivity, and real-time monitoring capabilities. In optical sensors, LDHs act as stable carriers for spectroscopically active molecules, improving host–guest interactions, reducing molecule aggregation, and enhancing optical responses of fluorophores and chemiluminescence reagents. In electrochemical sensors, LDH-based probes with stable and porous structures facilitate redox reactions, boosting sensor sensitivity. Moreover, customization with conductive materials like metal nanoparticles or graphene further improves catalytic activity and selectivity. This chapter aims to discuss the most significant applications and recent advancements in LDH-based sensing, particularly in optical and electrochemical sensors that take advantage of LDH–analyte interactions to modify electrochemical signals and spectral properties. The chapter closes with a brief discussion of the challenges and future directions needed to enhance LDH-based sensors and broaden their application in environmental monitoring and healthcare.