研究目的
To develop a sensitive and selective fluorescent turn-on probe for detecting cysteine and homocysteine in human serum, avoiding interference from glutathione.
研究成果
The developed Au NCs@KI3 probe enables sensitive and selective detection of cysteine and homocysteine with low detection limits (9 nM for Cys, 12 nM for Hcy) and good recovery in human serum samples. It shows potential for point-of-care clinical diagnostics due to its simplicity, cost-effectiveness, and ability to avoid glutathione interference. Future work should focus on improving discrimination between Cys and Hcy and expanding to other biological matrices.
研究不足
The probe may have limited applicability in highly acidic or basic conditions outside pH 6.0-10.5. Discrimination between cysteine and homocysteine is not fully achieved, requiring future studies. Potential interference from other thiols or matrix effects in complex biological samples could affect accuracy.
1：Experimental Design and Method Selection:
The study involves synthesizing bovine serum albumin-stabilized gold nanoclusters (Au NCs), quenching their fluorescence with potassium triiodide (KI3), and using this quenched state as a probe for turn-on detection of cysteine and homocysteine. The rationale is based on the aggregation-induced quenching by iodine and recovery by thiol groups in Cys/Hcy. Theoretical models include Stern-Volmer analysis for quenching and linear calibration for detection.
2：Sample Selection and Data Sources:
Human serum samples were collected from healthy volunteers with informed consent. Synthetic amino acids and other chemicals were used for selectivity studies.
3：List of Experimental Equipment and Materials:
Equipment includes a microwave oven for synthesis, fluorescence spectrometer for measurements, transmission electron microscope (TEM) for imaging, X-ray photoelectron spectrometer (XPS) for analysis, time-correlated single photon counting (TCSPC) system for lifetime measurements, and dynamic light scattering (DLS) for size analysis. Materials include hydrogen tetrachloroaurate trihydrate, bovine serum albumin, various amino acids, ascorbic acid, glutathione, potassium iodide, iodine, and Millipore water.
4：Experimental Procedures and Operational Workflow:
Au NCs were synthesized by reducing HAuCl4 with BSA under microwave heating. Quenching was optimized with different KI3 ratios. Detection involved mixing Au NCs with KI3, adding Cys/Hcy samples, equilibrating, and measuring fluorescence. pH studies, selectivity tests with other amino acids, and real sample analysis in serum were conducted. Paper strip tests were also performed.
5：Data Analysis Methods:
Fluorescence intensity ratios (I/I0) were used for calibration curves. Statistical analysis included linear regression for detection limits and R2 values. TCSPC provided fluorescence lifetime data, and TEM/DLS provided size distributions.
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