Fluorescent Probes

Fluorescent probes have become a key tool for biomedical and chemical detection due to their advantages of real-time imaging, high sensitivity, and low invasiveness. This chapter systematically reviews the core mechanism of fluorescent probes, including excitation mode (single-photon, two-photon, and upconversion luminescence), fluorescence reporting mode (enhancement, quenching, ratio type, lifetime type, and anisotropic type), the optical modulation mechanism (photon-induced electron transfer), intramolecular charge transfer, excited state intramolecular proton transfer, Förster resonance energy transfer, and aggregation-induced emission ), the reaction mechanism (covalent bond cleavage, coordination, protonation, etc. ). This chapter provides a theoretical basis for the design and optimization of fluorescent probes.