在这里,我们提出了一种基于氧化钨(VI)(WO3)纳米胶体颗粒对α-氨基酸(AA)分子的表面增强光致变色现象的比色检测方法,包括L-天冬氨酸(Asp),L-谷氨酸(Glu),L-组氨酸(His),L-异亮氨酸(Ile),L-亮氨酸(Leu),L-赖氨酸(Lys),L-苯丙氨酸(Phe),和L-缬氨酸(Val)。使用UV-Vis吸收光谱法研究了AA/WO3二元水体系中UV诱导的光致变色现象。已使用吸附等温线分析和衰减全反射傅里叶变换红外(ATR-FTIR)光谱相结合确定了WO3纳米胶体颗粒表面上AA分子的吸附性能。WO3纳米胶体颗粒表面吸附的AAs浓度与相应紫外线辐照的WO3胶体水溶液中的初始光致变色着色速率之间具有良好的线性相关关系,超过三个数量级,表明WO3纳米胶体颗粒的表面增强光致变色现象可用于检测AA分子。此外,根据紫外-可见吸收的结果,ATR-FTIR,和吸附等温线分析,我们已经通过实验证明了具有内球吸附Ile的AA/WO3二元水相体系,Leu,Lys,或Val分子在WO3纳米胶体颗粒的表面表现出更显著的表面增强光致变色现象比具有外球吸附Asp的系统,Glu,他的,或Phe分子。AA分子的强内球吸附成功地提高了检测限。这项研究为基于WO3纳米胶体探针的表面增强光致变色现象的“无标记”比色测定系统提供了有价值的见解。
Herein, we present a colorimetric detection method based on the surface-enhanced photochromic phenomenon of tungsten (VI) oxide (WO3) nanocolloid particles for α-amino acid (AA) molecules, including L-aspartic acid (Asp), L-glutamic acid (Glu), L-histidine (His), L-isoleucine (Ile), L-leucine (Leu), L-lysine (Lys), L-phenylalanine (Phe), and L-valine (Val). The UV-induced photochromic phenomena in the AA/WO3 binary aqueous systems were investigated using UV-Vis absorption spectrometry. The adsorption properties of the AA molecules on the surface of the WO3 nanocolloid particles have been identified using a combination of adsorption isotherm analysis and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. A good linear correlation between the concentration of the AAs adsorbed on the surface of the WO3 nanocolloid particles and the initial photochromic coloration rate in the corresponding UV-irradiated WO3 colloidal aqueous solution was obtained with over three orders of magnitude, indicating that the surface-enhanced photochromic phenomenon of the WO3 nanocolloid particle can be used to detect the AA molecules. In addition, based on the results of the UV-Vis absorption, ATR-FTIR, and adsorption isotherm analyses, we have experimentally demonstrated that the AA/WO3 binary aqueous system with inner-sphere adsorbed Ile, Leu, Lys, or Val molecules on the surface of the WO3 nanocolloid particles exhibits a more significant surface-enhanced photochromic phenomenon than the system with outer-sphere adsorbed Asp, Glu, His, or Phe molecules. The strong inner-sphere adsorption of the AA molecules successfully improved the limit of detection. This study provides valuable insights into a \"label-free\" colorimetric assay system based on the surface-enhanced photochromic phenomenon of the WO3 nanocolloid probe.