Design and development of a bright NIR fluorescent probe for selective HSA detection in human blood serum and urine

Human serum albumin (HSA), an important human blood protein, plays a critical role in maintaining osmotic pressure and facilitating the transport of various substances. Abnormal HSA levels are associated with diseases like kidney disease, heart problems, diabetes, and liver damage, necessitating the development of accurate methods for HSA detection. This paper describes the design, synthesis, and evaluation of four BODIPY-based near-infrared (NIR) fluorescent probes (BD1-BD4) for the selective detection of HSA. Among the synthesized probes, BD1 demonstrated exceptional sensitivity and specificity, exhibiting a 147-fold fluorescence enhancement at 660 nm (λ_ex = 600 nm) with a Stokes shift of 60 nm. The probe achieved a low detection limit of 9.5 nM, enabling the effective quantification of HSA in complex biological samples such as human blood serum and artificial urine. Competitive binding studies using ibuprofen confirmed that BD1 binds selectively to binding site II of HSA, which was further supported by a molecular docking study. Additionally, BD1 demonstrated HSA detection with a high recovery rate in artificial urine.