Molecular engineering of a fluorescent probe for highly efficient detection of human serum albumin in biological fluid

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 (λex = 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.

Tetraphenylethylene-indole as a novel fluorescent probe for selective and sensitive detection of human serum albumin (HSA) in biological matrices and monitoring of HSA purity and degradation

Human serum albumin (HSA) levels in serum and urine is a crucial biomarker for diagnosing liver and kidney diseases. HSA is used to treat various disorders in clinical practice and as an excipient in the production of vaccine or protein drug, ensuring its purity essential for patient safety. However, selective and sensitive detection of HSA remains challenging due to its structural similarity with bovine serum albumin (BSA) and the inherent complexity of biological matrices. This study presents a novel application of the tetraphenylethylene-indole (TPE-indo) fluorophore for the identification and quantification of HSA. The findings demonstrate that TPE-indo binds specifically to HSA in a 1:1 M ratio, thereby triggering its aggregation-induced emission (AIE) mechanism and producing a selective, sensitive, and rapid "turn-on" fluorescence response. The fluorescence intensity of TPE-indo exhibited minimal interference from proteins, amino acids, sugars, ions, and urine metabolites, and demonstrated a linear correlation with HSA concentration up to 60 μg/mL, with a limit of detection of 0.30 μg/mL. Furthermore, TPE-indo displays a markedly enhanced response to HSA in comparison to BSA, which can be ascribed to the distinct binding modes between TPE-indo and these two proteins. TPE-indo can be used to quantify HSA in serum, grade proteinuria samples, detect BSA adulteration in HSA samples, and real-time monitor HSA degradation processes. This study not only advances the development of efficient HSA detection methods but also highlights the significance of TPE-indo as a versatile tool for bioanalysis and clinical diagnosis.

A novel glass chip based lateral flow immunoassay of albumin

Lateral flow immunoassays typically rely on optical tests conducted on paper strips. However, the 3D matrix of paper embedded with optical nanoparticles often limits detection sensitivity and the ability of detection instruments to capture signals. This study introduces a novel approach using a glass chip-based lateral flow immunoassay, with albumin as a typical biomarker for detection, enabling the presence of the signal on a flat surface. Compared with traditional paper-based immunoassay, glass-based lateral flow immunoassay has achieved a uniform distribution pattern for albumin detection, lowered the limit of detection from 100 ng/mL to 1 ng/mL, and reduced detection time through an improved liquid mobility system. The glass-based method also shortens the detection time by 28.5% to 147.8 s compared to the traditional method. This research presents a new methodology for lateral flow immunoassays that can be applied to a wide range of biomarkers, with potential benefits for various medical and environmental applications.