Rational design of aptamer-based biosensors

鉴于人们对传染病、生物恐怖分子和环境污染的日益关注，迫切需要开发工具来快速准确地检测和识别低浓度目标。生物传感器是将生物识别事件转换为可测量反应的分析设备。为了合理设计生物传感器，我们必须为目标找到正确的识别元件，了解识别事件的机制，并制定将该事件转换为可测量信号的策略。抗体是当前生物传感的标准，因为它们与许多目标具有强烈和选择性的结合。然而，在稳定性和制备简便性方面，一些研究存在局限性。建议的研究计划旨在调查使用短片段的DNA或RNA作为新的生物传感器的构建块。适体是合成的DNA或RNA片段，其作用类似于抗体，与特定的靶点紧密结合，但还有一个额外的优势，即更容易制备，并表现出比抗体对应物更好的稳定性。适体已被开发出来与一系列对生物传感器重要的靶点结合：毒素、癌症标记物、蛋白质、甚至病毒。现在的挑战是设计生物传感器体系结构，它将接受适配子结合的识别事件，并将其转化为信号。在我们能够以理性的方式做到这一点之前，我们需要更好地了解适配子如何与其靶结合。我们的第一个目标是设计新的探针，以研究和理解当适配子与其靶结合时发生的结构变化，因为适配子形状的变化被认为是结合事件的关键。有了这些信息，我们就可以继续我们的第二个目标，设计和实现能够将适体结构的这种变化转化为可测量信号的体系结构。从长远来看，我们研究适体结构的系统方法和基于适体的新生物传感器的设计可以在从医疗诊断到环境监测的一系列环境传感方面取得重要进展。

Given increasing concerns about infectious diseases, bioterrorism agents, and environmental contaminants, there is an urgent need to develop the tools for rapid and accurate detection and identification of a target at low concentrations.  Biosensors are analytical devices that transduce a biological recognition event into a measurable response.  In order to rationally design biosensors, we must find the correct recognition element for the target, understand the mechanism of the recognition event, and develop the strategy for transducing that event into a measurable signal.  Antibodies are the current standard in biosensing, due to their strong and selective binding to many targets. However, some have limitations with regards to stability and ease of preparation.  The proposed research program seeks to investigate the use of short stretches of DNA or RNA, known as aptamers, as the building blocks for new biosensors.  Aptamers are synthetic pieces of DNA or RNA that act like antibodies, binding tightly to a specific target, but have the added advantage of being easier to prepare and demonstrating improved stability over their antibody counterparts.  Aptamers have been developed to bind to a host of targets that can be important analytes for biosensors: toxins, cancer markers, proteins, and even viruses.  Now the challenge is to design the biosensor architecture that will take the recognition event of aptamer binding and translate it into a signal.  Before we can do that in a rational manner we need a better understanding of how aptamers bind to their targets.  Our first goal is to design new probes to study and understand the structural changes that take place when an aptamer binds to its target, as the change in the shape of the aptamer is thought to be the key to the binding event.  With this information we can then proceed to our second goal, to design and implement architectures that can transduce this change in aptamer structure into a measurable signal.  In the long term, our systematic approach to the study of aptamer structure and the design of new aptamer-based biosensors could enable important advances in sensing for a range of milieus, from medical diagnostics to environmental monitoring.