School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, PR China.
School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, PR China; Shandong Provincial Key Laboratory of Preparation and Measurement of Building Materials, University of Jinan, Jinan 250022, PR China.
Biosens Bioelectron. 2016 May 15;79:416-22. doi: 10.1016/j.bios.2015.12.019. Epub 2015 Dec 11.
Combining multibranched hybridization chain reaction (mHCR), the photoelectrochemical (PEC) immunosensor was fabricated with a microfluidic paper-based analytical devices using different sizes of CdTe quantum dots (QDs) sensitized flower-like 3D ZnO superstructures as photoactive materials. Firstly, 4-aminothiophenol (PATP) functioned ZnO was anchored on gold-paper working electrode. With the aid of PATP, large-sized CdTe-COOH QDs (QDs1) were conjugated onto the ZnO surface because of the formation of a strong bond (Zn-S) between the thiol of PATP molecule and the ZnO, and the remaining amino group formed an amide bond with carboxylic acid group capping CdTe. Then the small-sized CdTe-NH2 QDs (QDs2) were modified on the QDs1 by forming amide bond, which leaded to a very strong photocurrent response because of the formation of cosensitized structure. The designed mHCR produced long products with multiple branched arms, which could attached multiple PdAu nanoparticles and catalyze the oxidation of hydroquinone (HQ) using H2O2 as anoxidant. Double strands DNA with multiple branched arms (mdsDNA) was formed by mHCR. In the presence of carcinoembryonic antigen (CEA), PdAu-mdsDNA conjugates-labeled CEA antibody was captured. The concentrations of CEA were measured through the decrease in photocurrent intensity resulting from the increase in steric hindrance of the immunocomplex and the polymeric oxidation product of HQ. In addition, the oxidation product of HQ deposited on the as-obtained electrode, which could efficiently inhibit the photoinduced electron transfer. Under optimal conditions, the PEC immunosensor exhibited excellent analytical performance: the detection range of CEA was from 0.001 to 90 ng mL(-1) with low detection limit of 0.33 pg mL(-1). The as-obtained immunosensor exhibited excellent precision, prominent specificity, acceptable stability and reproducibility, and could be used for the detection of CEA in real samples. The proposed assay opens a promising platform of clinical immunoassay for other biomolecules.
采用多分支杂交链式反应 (mHCR)，结合光电化学 (PEC) 免疫传感器，使用不同尺寸的碲化镉量子点 (QDs) 敏化花状 3D ZnO 超结构作为光活性材料，在微流控纸基分析器件上进行构建。首先，将 4-巯基苯硼酸 (PATP) 功能化的 ZnO 锚定在金纸工作电极上。由于 PATP 分子的巯基与 ZnO 之间形成了强键 (Zn-S)，较大尺寸的碲化镉-COOH QDs (QDs1) 被接枝到 ZnO 表面，而剩余的氨基则与羧酸基团形成酰胺键，从而对 QDs1 进行了封端。然后，通过形成酰胺键将小尺寸的 CdTe-NH2 QDs (QDs2) 修饰在 QDs1 上，由于形成了共敏化结构，导致了非常强的光电流响应。设计的 mHCR 产生了具有多个分支臂的长产物，这些产物可以附着多个 PdAu 纳米颗粒，并使用 H2O2 作为氧化剂催化对苯二酚 (HQ) 的氧化。mHCR 产生了具有多个分支臂的双链 DNA (mdsDNA)。在癌胚抗原 (CEA) 的存在下，PdAu-mdsDNA 缀合物标记的 CEA 抗体被捕获。通过免疫复合物和 HQ 的聚合氧化产物增加引起的空间位阻增加，来测量 CEA 的浓度。此外，在获得的电极上沉积的 HQ 的氧化产物，可有效地抑制光诱导电子转移。在最佳条件下，PEC 免疫传感器表现出优异的分析性能：CEA 的检测范围为 0.001 至 90 ng mL(-1)，检测限低至 0.33 pg mL(-1)。所获得的免疫传感器表现出优异的精密度、突出的特异性、可接受的稳定性和重现性，可用于检测真实样品中的 CEA。该方法为其他生物分子的临床免疫分析开辟了一个有前景的平台。
