An NIR fluorescent probe for dynamic monitoring of β-lactoglobulin: from milk quality analysis to biological imaging

Abstract

Dynamic monitoring of β-lactoglobulin (β-LG) stability plays a crucial role in evaluating dairy product quality and understanding its biological functions. While some fluorescent probes are capable of real-time β-LG monitoring, achieving reliable long-term detection requires a probe that possesses intrinsic stability and can overcome severe background interference and high light scattering in complex matrices. Herein, a novel near-infrared (NIR) fluorescent probe, DDT, was specifically designed for the dynamic monitoring of β-LG. The probe exhibited high selectivity and sensitivity toward β-LG. Dual-mode quantification of β-LG in liquid milk was achieved using DDT via a fluorescence assay and a smartphone-based colorimetric platform. Furthermore, DDT enabled long-term monitoring of milk stability by accurately tracking β-LG degradation. Additionally, DDT served as a reliable tool for dynamically monitoring β-LG uptake and distribution in living cells and in vivo. DDT demonstrates significant potential as a versatile tool for food safety diagnostics and biological research.