College of Chemistry and Materials Science, Anhui Key Laboratory of Chemo/Biosensing, The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Laboratory of Molecule-based Materials, Anhui Normal University, Wuhu 241000, China.
College of Chemistry and Materials Science, Anhui Key Laboratory of Chemo/Biosensing, The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Laboratory of Molecule-based Materials, Anhui Normal University, Wuhu 241000, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2023 Feb 5;286:121951. doi: 10.1016/j.saa.2022.121951. Epub 2022 Oct 7.
Histidine (His) is a natural amino acid that plays very important roles in biota. However, the low concentrations of His in biological fluids and the similar structures and properties of other amino acids mean it is difficult to selectively determine His concentrations in biological fluids with a high degree of sensitivity. A novel ratiometric fluorescence probe for detecting His in aqueous solutions is described here. The method involves carbon dots (CDs) and calcein/Ni complexes. At an excitation wavelength of 480 nm, the CD/calcein system emits green fluorescence (maximum emission from calcein at 512 nm) and red fluorescence (maximum emission from CDs at 617 nm). The presence of Ni decreases the calcein fluorescence intensity because of static quenching caused by the formation of calcein/Ni complexes but the CD fluorescence intensity remains almost unchanged. Fluorescence of calcein/Ni complexes provides the response, and the presence of His binds to Ni via cooperative chelation and produces free calcein causing fluorescence to be recovered. CDs provide a self-calibration fluorescence signal, the intensity of which remains almost unchanged in the presence of His. The ratio of the fluorescence intensities at 512 and 617 nm (I/I) was strongly related to the His concentration in the range 0.5-22 μM, and the detection limit was 0.16 μM. The specificity of Ni/His interactions allows His to be determined without interference from other species. The method was successfully used to determine His in diluted human urine. The recovery was acceptable, suggesting that the biosensor can be used to determine His in real samples.
组氨酸（His）是一种天然氨基酸，在生物群中起着非常重要的作用。然而，生物体液中 His 的浓度较低，且其他氨基酸的结构和性质相似，这意味着很难用高灵敏度的方法选择性地测定生物体液中的 His 浓度。本文描述了一种用于检测水溶液中 His 的新型比率荧光探针。该方法涉及碳点（CDs）和钙黄绿素/Ni 配合物。在 480nm 的激发波长下，CD/钙黄绿素体系发射出绿色荧光（钙黄绿素的最大发射波长为 512nm）和红色荧光（CDs 的最大发射波长为 617nm）。由于形成钙黄绿素/Ni 配合物引起的静态猝灭，Ni 的存在降低了钙黄绿素的荧光强度，但 CD 的荧光强度几乎保持不变。钙黄绿素/Ni 配合物的荧光提供了响应，而 His 的存在通过协同螯合与 Ni 结合，产生游离的钙黄绿素，从而使荧光恢复。CDs 提供了一个自校准的荧光信号，其强度在存在 His 的情况下几乎保持不变。512nm 和 617nm 处的荧光强度比（I/I）与 0.5-22μM 范围内的 His 浓度呈强相关，检测限为 0.16μM。Ni/His 相互作用的特异性允许在没有其他物质干扰的情况下测定 His。该方法成功地用于测定稀释的人尿中的 His。回收率可以接受，表明该生物传感器可用于测定真实样品中的 His。
