Quantification of human serum albumin by combining chymotrypsin/trypsin digestion coupled with LC-MS/MS technique

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.

Synthesis of Silver Nanoparticles and Gold Nanoparticles Used as Biosensors for the Detection of Human Serum Albumin-Diagnosed Kidney Disease

Background/Objectives: This study aims to develop a screen-printed carbon electrode (SPCE) modified with silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) for the detection of human serum albumin (HSA). The objectives include utilizing green synthesis methods for nanoparticle production and evaluating the electrochemical performance of the modified electrodes. Methods: AgNPs and AuNPs were synthesized using Phulae pineapple peel extract (PPA) as a reducing agent. The nanoparticles were characterized using UV-visible spectrophotometry (UV-vis), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The electrochemical performance of AgNP/SPCE and AuNP/SPCE was assessed by cyclic voltammetry (CV) studies, and the electrodes were functionalized with anti-HSA antibodies for HSA detection. Results: Characterization revealed spherical nanoparticles ranging from 10 to 30 nm. Both AgNP/SPCE and AuNP/SPCE demonstrated improved electrochemical performance compared to bare SPCEs. The modified sensors could detect serum albumin concentrations from 10 to 400 μg/mL, with high correlation values of 0.97 and 0.99 for AgNPs and AuNPs, respectively. Conclusions: This research demonstrates the potential of using agricultural waste for green synthesis of nanoparticles and highlights the application of AgNPs and AuNPs in developing sensitive biosensing platforms for the detection of human serum albumin.

Characterization of a Novel Antimicrobial Peptide Bacipeptin against Foodborne Pathogens

The increasing emergence of multidrug-resistant pathogens and development of biopreservatives in food industries has increased the demand of novel and safe antimicrobial agents. In this study, a marine bacterial strain Bacillus licheniformis M1 was isolated and exhibited obvious antimicrobial activities against foodborne pathogens, especially against methicillin-resistant Staphylococcus aureus. The antimicrobial agent was purified and identified as a novel antimicrobial peptide, which was designated as bacipeptin, and the corresponding mechanism was further investigated by electron microscopy observation and transcriptomic analysis with biochemical validation. The results showed that bacipeptin could reduce the virulence of methicillin-resistant Staphylococcus aureus and exerted its antimicrobial activity by interfering with histidine metabolism, inducing the accumulation of reactive oxygen species and down-regulating genes related to Na+/H+ antiporter and the cell wall, thus causing damage to the cell wall and membrane. Overall, our study provides a novel natural product against foodborne pathogens and discloses the corresponding action mechanism.