表面增强拉曼光谱快速检测尿液中的尿酸

表面增强拉曼光谱是一种表面灵敏度极高的"指纹"光谱技术,检测限可达单分子级别。它可以实现痕量物质的特异性识别及快速、无损检测,广泛应用于生命科学、电化学、环境安全等领域以及人们的日常生活中。通过种子生长法成功地实现了形貌均匀、尺寸可调的球形金纳米粒子的制备,并以此作为增强基底进一步探索其粒径对尿酸拉曼谱峰强度的影响。结果表明,金纳米粒子的尺寸显著影响其拉曼增强能力。在研究范围内,随着金纳米粒子尺寸的增加,其拉曼增强能力逐渐增加。在激光波长为638nm时,150nm的金纳米粒子具有最优的拉曼增强能力。这使得它们可适用于尿酸溶液的快速高灵敏度分析,检测限可达0.01mmol·L~(-1)。进一步的研究还表明,该方法可用于痕量尿酸的定量检测。在0.01~0.5mmol·L~(-1)范围内,尿酸的浓度与其特征拉曼峰640cm~(-1)处的峰强度之间呈线性关系,线性相关系数达0.98。将该方法用于真实样品(正常人体尿液)的快速检测,发现该方法不受尿液中其他成分的干扰,可以实现人体尿液中尿酸含量的快速测定。研究结果表明,以金纳米粒子作为基底的表面增强拉曼光谱方法可方便、快速地对尿液中尿酸的含量进行分析,极大地拓展了表面增强拉曼光谱在临床上的应用与研究。

Surface-Enhanced Raman Spectroscopy for Rapid Detection of Uric Acid in the Urine

Surface-enhanced Raman spectroscopy (SERS) is a fingerprint technique with ultra-high surface sensitivity down to single-molecule level.It can be used for specific,fast and nondestructive detection of trace amounts of molecules,which has been widely applied in various fields,such as life sciences,electrochemistry,environmental safety and even our daily life.Herein,highly uniform Au nanoparticles with tunable sizes are prepared via a seed growth method.They have been used as SERS substrates for detection of uric acid.Size dependent SERS enhancements have been found for the Au nanoparticles,and the enhancements increase with the particle size.Au nanoparticles with size of 150 nm are the optimized substrate for the detection of uric acid,when the laser with wavelength of 638 nm is used as exciting light.The detection limit of uric acid is 0.01 mmol · L-1.It has also been found that Au nanoparticles could be used for the quantitative detection of uric acid.The result shows that there is a linear relationship between the Raman intensity of the peak at 640 cm-1 and the concentrations of uric acid in the range of 0.01 ～0.5 mrnol · L-1.Therefore,this method can be used for rapid detection of real samples (normal human urine).It is not affected by the interference of other components in urine,thus,it can realize the rapid determination of uric acid in human urine.This work greatly expands the clinical application of surface enhanced Raman spectroscopy.