School of Pharmacy, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of China.
Mikrochim Acta. 2019 Jul 17;186(8):544. doi: 10.1007/s00604-019-3516-4.
A fluorometric method is described for the determination of mucin 1 (MUC1). It is based on the specific binding of MUC1 by anti-MUC1 aptamers and by exploiting the inner filter effect (IFE) exerted by gold nanoparticles (AuNPs) on the blue fluorescence of carbon dots (CDs). When CDs are mixed with AuNPs, their fluorescence is reduced due to an IFE. The IFE efficiency can be modulated by the adsorption and the aggregation state of AuNPs. The latter can be induced by addition of salt, thereby allowing the fluorescence of the CDs to recover. The aptamer is adsorbed on the AuNPs and protects the AuNPs from salt-induced aggregation which is accompanied by a color change from red to blue. If aptamer is added to a mixture of CDs and AuNPs in presence of salt, the aggregation of the AuNPs is inhibited. Thus, the blue fluorescence of the CDs (best measured at excitation/emission wavelengths of 365/448 nm) is reduced. If, however, the aptamers bind MUC1, the aptamers will be released from the surface of the AuNPs. This decreases the salt tolerance of AuNPs and leads to the recovery of the blue fluorescence. The fluorescence intensity increases with the concentration of MUC1. The method has a linear response in the 5.3 to 200 ng·mL MUC1 concentration range and a lower detection limit of 5.3 ng·mL. The method displays excellent selectivity towards MUC1 against other proteins. Graphical abstract Schematic illustration of (I) the influence of IFE of free AuNPs and NaCl aggregated AuNPs and (II) the influence of specific interaction between MUC1 and aptamers on the NaCl-induced aggregation of AuNPs and the IFE efficiency.
一种荧光法用于测定黏蛋白 1（MUC1）。它基于 MUC1 与抗 MUC1 适体的特异性结合，并利用金纳米粒子（AuNPs）对碳点（CDs）的蓝色荧光的内滤效应（IFE）。当 CDs 与 AuNPs 混合时，由于IFE，其荧光会降低。IFE 效率可以通过 AuNPs 的吸附和聚集状态来调节。后者可以通过添加盐来诱导，从而使 CDs 的荧光恢复。适体被吸附在 AuNPs 上，并保护 AuNPs 免受盐诱导的聚集，这伴随着颜色从红色变为蓝色的变化。如果在存在盐的情况下将适体添加到 CDs 和 AuNPs 的混合物中，则 AuNPs 的聚集被抑制。因此，CDs 的蓝色荧光（最佳激发/发射波长为 365/448nm）会降低。然而，如果适体结合 MUC1，则适体将从 AuNPs 的表面释放出来。这降低了 AuNPs 的耐盐性，并导致蓝色荧光的恢复。荧光强度随 MUC1 浓度的增加而增加。该方法在 5.3 至 200ng·mL MUC1 浓度范围内具有线性响应，检测限低至 5.3ng·mL。该方法对 MUC1 表现出优异的选择性，对其他蛋白质具有较高的选择性。
