Mechanistic Overview on Fluorimetric Sensors for Detection and Bioimaging of Fe(II & III)

Imbalance in iron concentration is associated with several physiological disorders. Considering that, development of highly efficient and convenient tools for quantitative detection of iron is of immense worth in terms of environmental and public health management. In this context, fluorescence chemosensing of Fe³⁺ and Fe²⁺ evolved as simple, rapid and economic technology. The present review aims to cover the recent advances (2019-2024) in fluorescence-based sensing of iron. Small molecule sensors of Fe³⁺ and Fe²⁺ have been classified into some major categories based on their sensing mechanism. These include photo-induced electron transfer, intramolecular charge transfer, excited-state intramolecular proton transfer, ligand to metal and metal to ligand charge transfer, aggregation-induced emission etc. The main focus of the review has been placed on the design, selectivity, sensitivity and in some cases bioimaging applications of the molecular probes of iron. The challenges and prospects of those probes have been evaluated critically, which will provide new insights and guidance for further design and development of fluorescence probes for iron.