Mechanism elucidation of cell-selective fluorescent probes

Cell-selective fluorescent probes have emerged as essential tools for live-cell imaging, enabling the differentiation of specific cell types within complex biological systems. Unlike traditional antibody-based methods that target extracellular proteins, small-molecule probes can access intracellular environments and exploit diverse biochemical features for selective retention or activation. This perspective categorizes the mechanisms of cell selectivity into five principal strategies: Protein-oriented, carbohydrate-oriented, lipid-oriented, gating-oriented, and metabolism-oriented live-cell distinctions. Each class capitalizes on a unique cellular trait ranging from protein expression and membrane composition to transporter activity and metabolic enzyme presence. We discuss representative examples of each mechanism, outline a decision-tree workflow for elucidating a new probe's mode of action, and highlight how understanding these mechanisms is critical for both basic biological research and therapeutic probe design. Looking ahead, the development of such mechanism-informed cell-specific probes holds promise for advancing precision cell targeting in biomedical applications.