Novel methods for selecting signaling aptamers

生物传感器依靠蛋白质和脱氧核糖核酸(DNA)等生物分子进行检测。众所周知的例子包括血糖仪和验孕试剂盒。前者使糖尿病患者的医疗保健发生了革命性的变化；后者是目前诊断怀孕的金标准。如果更多的疾病或症状，如癌症和心脏病发作，可以很容易地诊断出来，那么更多的人将从生物传感器中受益。同样重要的是环境污染物的检测。长期以来，DNA一直以其作为遗传物质的功能而闻名。最近，人们发现某些单链DNA序列可以与许多分子特异结合，这些结合的DNA被称为DNA适配子。与抗体相比，DNA适配子具有相似甚至更好的结合性能，更高的稳定性和更低的成本。因此，适配子作为一类新型的生物传感器试剂正在兴起。适体是通过选择程序获得的。从包含数百万亿随机DNA的巨大文库开始，只选择和扩增能与目标分子结合的序列。虽然这种方法已经成功地应用于适配子的选择，但它有几个主要的缺点，包括需要将目标分子连接到一根柱子和多轮(通常是&gt；10)选择。目前，只有少数高质量的小分子DNA适配子可用。为了解决这些问题，我建议通过DNA文库固定化来开发新的适体选择方法。最初的选择目标包括与疾病相关的激素、营养物质和环境污染物。包括研究生和本科生在内的一批高素质人才将通过这一研究计划进行培训。他们将接触到高度交叉和多学科的研究环境，学习各种分子生物学和分析化学技术，并开发基于纳米技术的新方法。预计拟议中的研究将有益于加拿大的医疗保健、环境和经济。

Biosensors rely on biomolecules such as proteins and deoxyribonucleic acids (DNAs) for detection. Well-known examples include glucose meters and pregnancy test kits. The former has revolutionized the health care of diabetic patients; and the latter is the current gold standard for diagnosis of pregnancy. Many more people will benefit from biosensors if more diseases or symptoms, such as cancer and heart attack, can be easily diagnosed. Of equal importance is the detection of environmental contaminants. DNA has been known for its function as a genetic material for a long time. Recently, it was discovered that certain sequences of single-stranded DNAs can specifically bind many molecules and these binding DNAs are called DNA aptamers. Compared to antibodies, DNA aptamers have similar or even better binding performance, higher stability and lower cost. Therefore, aptamers are emerging as a new class of reagent for biosensor design. Aptamers are obtained through a selection procedure. Starting with a huge library containing hundreds of trillions of random DNAs, only sequences that can bind target molecules are selected and amplified. Although this method has been successfully applied for aptamer selection, it has several main drawbacks including the needs of linking target molecules to a column and multiple rounds (generally >10) of selection. Currently, only a few high-quality DNA aptamers for small molecules are available. To address these problems, I propose to develop novel aptamer selection methods through DNA library immobilization. Initial targets for selection include disease related hormones, nutrients, and environmental contaminants. A number of highly qualified personnel including graduate and undergraduate students will be trained with this research program. They will be exposed to a highly inter- and multi-disciplinary research environment, learn various molecular biology and analytical chemistry techniques, and develop new nanotechnology-based methods. It is expected that the proposed research will benefit Canada's health care, the environment, and economy.