Silver clusters embedded within zeolites for innovative (bio)sensing platforms

Silver clusters embedded within zeolites combine the molecular-like optical and electrochemical properties of sub-nanometric clusters with the structural robustness, porosity, and ion-exchange capacity of crystalline frameworks. Their unique features, such as tunable emission with high quantum yields, large Stokes shifts, redox activity, electrocatalytic behavior, and sensitivity to external stimuli, enable versatile sensing capabilities. These composites have already demonstrated remarkable versatility, enabling optical detection of water vapor, volatile amines, oxygen, and biomolecules, as well as electrochemical sensing of hydrogen peroxide, tryptophan, and chloride ions. Their integration into immunosensors, optical hydration switches, and electrochemical paper-based strips highlights their disruptive potential for portable and wearable devices. However, key challenges remain, including controlled nucleation, tailoring excitation-emission properties, and ensuring stability after biorecognition functionalization and device integration. This review discusses the structure-property relationships that govern the optical and electrochemical responses of silver clusters embedded within zeolites, summarizes recent advances in (bio)sensing applications, and outlines the challenges that must be overcome for their translation into scalable, robust, and sustainable devices. With continued progress in material design, surface functionalization, and integration within microfluidic and data analysis platforms, silver cluster-zeolite composites hold strong promise to evolve from laboratory prototypes into portable technologies for diagnostics and environmental monitoring, displaying significant promises for next-generation point-of-care and wearable sensors.