Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan.
The Ph.D. Program for Translational Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei 11031, Taiwan.
Sensors (Basel). 2023 Aug 27;23(17):7453. doi: 10.3390/s23177453.
A uniformly oriented purple membrane (PM) monolayer containing photoactive bacteriorhodopsin has recently been applied as a sensitive photoelectric transducer to assay color proteins and microbes quantitatively. This study extends its application to detecting small molecules, using adenosine triphosphate (ATP) as an example. A reverse detection method is used, which employs AuNPs labeling and specific DNA strand displacement. A PM monolayer-coated electrode is first covalently conjugated with an ATP-specific nucleic acid aptamer and then hybridized with another gold nanoparticle-labeled nucleic acid strand with a sequence that is partially complementary to the ATP aptamer, in order to significantly minimize the photocurrent that is generated by the PM. The resulting ATP-sensing chip restores its photocurrent production in the presence of ATP, and the photocurrent recovers more effectively as the ATP concentration increases. Direct and single-step ATP detection is achieved in 15 min, with detection limits of 5 nM and a dynamic range of 5 nM-0.1 mM. The sensing chip exhibits high selectivity against other ATP analogs and is satisfactorily stable in storage. The ATP-sensing chip is used to assay bacterial populations and achieves a detection limit for and of 10 and 10 CFU/mL, respectively. The demonstration shows that a variety of small molecules can be simultaneously quantified using PM-based biosensors.
最近，一种具有定向排列的紫色膜（PM）单层，其中含有光活性菌视紫红质，已被用作敏感的光电传感器，用于定量检测色蛋白和微生物。本研究将其应用扩展到检测小分子，以三磷酸腺苷（ATP）为例。采用反向检测方法，使用金纳米粒子（AuNPs）标记和特定的 DNA 链置换。首先将 PM 单层涂覆的电极通过共价键与 ATP 特异性核酸适体偶联，然后与另一条带有与 ATP 适体部分互补序列的金纳米粒子标记的核酸链杂交，以显著减小 PM 产生的光电流。所得的 ATP 传感芯片在存在 ATP 的情况下恢复其光电流产生，并且随着 ATP 浓度的增加，光电流的恢复更有效。在 15 分钟内实现了直接和单步 ATP 检测，检测限为 5 nM，动态范围为 5 nM-0.1 mM。该传感芯片对其他 ATP 类似物具有高选择性，在储存中稳定性良好。该 ATP 传感芯片用于检测细菌种群，对 和 的检测限分别为 10 和 10 CFU/mL。该结果表明，使用基于 PM 的生物传感器可以同时定量检测多种小分子。
