Aptamers are the evidence of the power and versatility of DNA. In the biosensing field, if the important properties of aptamers together with all the many different conformations they can adopt are coupled to the proper transduction system, an unthinkable amount of possibilities is open up to construct biosensing methods for, in principle, any imaginable target. Inspired by classical molecular beacons, by using the intrinsic property of aptamers of changing their conformation when binding to the target and the possibility of labelling and coupling them to other DNA sequences, nanomaterials or polymers, a large variety of “turn on” or “turn off” optical biosensing systems, can be developed.

This review gives an overview of the recent works dealing with aptamers as optical switches in biosensing. Several optical approaches based on luminescence are considered, ranging from fluorescence, to chemi/bio luminescence, to plasmon field-enhanced fluorescence. The attractive combination of aptamer optical switches and nanomaterials is also discussed. Finally, the appealing and challenging application of aptamer optical switches to intracellular sensing and imaging is presented.

适体是DNA强大和多功能的证据。在生物传感领域，如果适体的重要特性以及它们可以采用的所有许多不同构象与适当的转导系统相结合，那么就原理上而言，为任何可想象的靶标构建生物传感方法都将面临不可思议的可能性。受到经典分子信标的启发，通过使用适体的固有特性在与靶标结合时改变其构象以及将其标记并偶联至其他DNA序列，纳米材料或聚合物的可能性，可以进行多种“开启”或“翻转”可以开发“ off”光学生物传感系统。

这篇综述概述了将适配体作为生物传感中的光学开关的最新工作。考虑了几种基于发光的光学方法，范围从荧光到化学/生物发光到等离子体激元场增强荧光。还讨论了适体光开关和纳米材料的有吸引力的组合。最后，介绍了适体光开关在细胞内感测和成像中的吸引力和挑战性应用。