Rational design of aptamer-based biosensors

鉴于人们对传染病、生物恐怖主义制剂和环境污染物的日益关注，迫切需要开发能够快速准确地检测和识别低浓度目标的工具。生物传感器是将生物识别事件转化为可测量响应的分析装置。为了合理设计生物传感器，我们必须找到正确的目标识别元件，了解识别事件的机制，并制定将该事件转导为可测量信号的策略。抗体是目前生物传感的标准，因为它们与许多靶标有很强的选择性结合。然而，有些在稳定性和制备的便捷性方面存在局限性。拟议的研究计划旨在研究DNA或RNA的短片段，即适体，作为新型生物传感器的构建模块。适配体是一种合成的DNA或RNA片段，其作用类似于抗体，与特定的靶标紧密结合，但它还有一个额外的优势，即更容易制备，并且比对应的抗体表现出更高的稳定性。适配体已经被开发出来，可以与许多目标结合，这些目标可以成为生物传感器的重要分析物：毒素、癌症标志物、蛋白质，甚至病毒。现在的挑战是设计生物传感器结构，将核酸适体结合的识别事件并将其转化为信号。在我们以理性的方式做到这一点之前，我们需要更好地了解适体是如何与它们的目标结合的。我们的第一个目标是设计新的探针来研究和理解适体与靶标结合时发生的结构变化，因为适体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，设计和实现可以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，我们对适配体结构的系统研究和基于适配体的新型生物传感器的设计可以使从医疗诊断到环境监测等一系列环境的传感取得重要进展。

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.