Green Synthesis of Silver Nanoparticles from Desert Plant Extracts from the Qassim Region for Optical Sensing Applications: A Comprehensive Review

The synthesis of luminous metal nanoclusters (MNCs) from natural plant sources is a long-lasting and cost-effective approach to developing improved optical sensors. This thorough study examines the potential of two desert plant species native to the Qassim region of Saudi Arabia as biomediators for the green synthesis of silver nanoclusters (AgNCs) for optical sensing. Desert plants accumulate a wide range of secondary metabolites, such as flavonoids, phenolic compounds, and tannins, that are effective at stabilizing and reducing MNCs. Silver nanoclusters exhibit strong photoluminescence, significant Stokes shifts, and high selectivity for heavy metal ions, making them ideal for building inexpensive, easy-to-use optical sensors. This review brings together what we know about (1) the botanical and phytochemical properties of plant extracts from the Qassim region, (2) the principles and mechanisms of green synthesis of AgNCs using plant extracts, (3) the optical properties and sensing mechanisms of luminescent AgNCs, (4) recent advances in AgNC-based fluorescence sensors for finding toxic metal ions and biomolecules, and (5) the possible scale-up and practical use of plant-derived AgNCs in clinical and environmental settings. The focus is on creating optical sensors that are sensitive, selective, and reversible, with detection limits in the nanomolar range, by employing fluorescence quenching and amplification methods. The combination of traditional ethnobotanical knowledge with current analytical chemistry and nanotechnology demonstrates that it is possible to develop new optical biosensing platforms using plants native to Saudi Arabia.