Fluorescent Zn (II) Coordination Complexes as Advanced Bioimaging Probes for Sensitive Detection of Small Biomolecules

Abstract

Advancements in diagnostic imaging have significantly improved early disease detection. Techniques such as computed tomography (CT), positron emission tomography (PET), magnetic resonance imaging (MRI), and ultrasound are widely used in clinical settings, each offering distinct advantages and limitations. These modalities are essential for monitoring disease progression and guiding therapeutic decisions. Recently, fluorescence imaging has gained considerable attention due to its high sensitivity, cost-effectiveness, and relative safety. FDA-approved fluorescent organic dyes are currently employed in limited clinical applications, including image-guided tumor surgery and retinal angiography. Emerging developments in fluorescence technology are driving the next generation of imaging agents. This review highlights the potential of mono- and binuclear Zn (II)-based coordination complexes as selective fluorescent probes for detecting small biomolecules such as phosphate, pyrophosphate, nucleotides, amino acids, sulfide, nitric oxide, and nitrate. We discuss the structural features and binding mechanisms that govern the fluorescence properties of these Zn (II) complexes, providing insights into their design principles. These findings lay the groundwork for developing innovative biosensors aimed at the early diagnosis of diseases through precise molecular recognition.