NIR emissive fluorescence turn-on probe for selective detection of serum albumin proteins in biofluids and living cells

The quantitative detection of serum albumin in body fluids and living cells is crucial for the diagnosis of various diseases. Here, we report a near-infrared (NIR) emissive fluorescent probe with an emission at around 800 nm for the selective and sensitive detection of both bovine serum albumin (BSA) and human serum albumin (HSA) in biofluids and in living cells. The probe showed turn-on fluorescence upon interaction with both proteins. The docking simulation studies confirmed the strong binding of the probes to the proteins. Electrostatic, hydrophobic, and hydrogen bonding interactions with the neighboring amino acid residues played a major role in the binding of the probe. The fluorescence intensity of the probe was found to be stable within the physiological pH of the mammalian cells. The probe was highly efficient in detecting BSA in fetal bovine serum (FBS) with a limit of detection (LOD) of 12 nM, while it detected the HSA from urine with LOD of 18.2 nM. The probe showed its efficient potential for in-vitro sensing of both the proteins in HeLa and HEK 293T cells.