Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education, College of Chemistry and Chemical Engineering , Southwest University , Chongqing 400715 , People's Republic of China.
Anal Chem. 2019 Aug 20;91(16):10864-10869. doi: 10.1021/acs.analchem.9b02600. Epub 2019 Aug 8.
Here, we fabricated a novel photoelectrochemical (PEC) aptasensor based on Br,N-codoped TiO/CdS quantum dots (QDs) sensitization structure with excellent energy level arrangement for supersensitive detection of carcinoembryonic antigen (CEA). The prepared Br,N-codoped TiO could reduce the energy bandwidth of TiO from 3.2 to 2.88 eV, which could dramatically reduce the basic signal and obviously broaden the absorption of light (400-700 nm). In addition, the energy bandwidth of Br,N-codoped TiO (2.88 eV) matched well with that of CdS QDs (2.4 eV), making CdS QDs an ideal signal enhancer for amplifying the photocurrent signal of Br,N-codoped TiO. More importantly, the constructed Br,N-codoped TiO/CdS QDs sensitization structure with narrow energy level gradient enabled the effective promotion of electron-transfer capability and dramatic improvement of photoelectric conversion efficiency. Simultaneously, a small amount of the CEA was transformed into substantial single-chain DNA (T-DNA) via exonuclease III (Exo-III)-assisted cycle strategy. Under optimum conditions, the designed PEC aptasensor demonstrated a wide detection range from 1 fg/mL to 1 ng/mL and a low detection limit as 0.46 fg/mL for CEA assay. This strategy prepared a new photoactive material to markedly improve photoelectric conversion efficiency and initiated a new way to realize the highly sensitive PEC biomolecules detection.
在这里，我们制造了一种新型的光电化学（PEC）适体传感器，基于 Br，N 共掺杂 TiO/CdS 量子点（QDs）敏化结构，具有优异的能级排列，用于超灵敏检测癌胚抗原（CEA）。所制备的 Br，N 共掺杂 TiO 可以将 TiO 的能带宽度从 3.2 降低到 2.88 eV，这可以显著降低基本信号并明显拓宽光的吸收（400-700nm）。此外，Br，N 共掺杂 TiO 的能带宽度（2.88 eV）与 CdS QDs 的能带宽度（2.4 eV）匹配良好，使 CdS QDs 成为放大 Br，N 共掺杂 TiO 的光电流信号的理想信号增强剂。更重要的是，构建的 Br，N 共掺杂 TiO/CdS QDs 敏化结构具有狭窄的能级梯度，使电子转移能力得到有效提升，光电转换效率得到显著提高。同时，少量的 CEA 通过外切酶 III（Exo-III）辅助循环策略转化为大量的单链 DNA（T-DNA）。在最佳条件下，设计的 PEC 适体传感器在 1 fg/mL 至 1 ng/mL 的宽检测范围内表现出良好的检测性能，对 CEA 的检测限低至 0.46 fg/mL。该策略制备了一种新型光活性材料，显著提高了光电转换效率，并为实现高灵敏度的 PEC 生物分子检测开辟了新途径。
