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Biosensing using DNA Nanoreactors that Transform Chromophoric Silver Clusters

使用 DNA 纳米反应器转化发色银簇进行生物传感

基本信息

批准号：
8491043
负责人：
Jeffrey Thomas Petty
金额：
$ 32.32万
依托单位：
FURMAN UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-05-01 至 2018-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8491043
关键词：
2-Aminopurine Adenine Affinity Base Pair Mismatch Base Pairing Binding Binding Sites Biochemical Biocompatible Biological Biological Markers Biological Process Biosensing Techniques Chemical Agents Chemicals Circular Dichroism Cleaved cell Commit Communities Complex Coupled DNA DNA Binding DNA Folding DNA Structure Detection Development Diagnosis Diagnostic Discrimination Encapsulated Entropy Environment Event Feedback Fluorescence Fluorescent Probes Foundations Glean Goals Growth Hybrids Image In Vitro Ionic Strengths Ligands Link Maps Measurement Measures Methodology MicroRNAs Molecular Monitor Oligonucleotides Optics Oxidants Quantum Dots Reaction Relative (related person)Relaxation Research Role Sampling Scheme Secondary to Serum Shapes Signal Transduction Silver Solvents Source Specificity Spectrum Analysis Structure Students Surveys Temperature Thermodynamics Training Universities Variant Viola Work absorption analog base chromophore computerized data processing cost design enthalpy experience high school human disease in vivo insight instrumentation nanomaterials novel nucleobase public health relevance quantum response sensor stoichiometry tool

项目摘要

DESCRIPTION (provided by applicant): Fluorescence is a powerful tool for biological analysis, but background interference can necessitate extensive purification for in vitro analysis and can severely constrain in vivo studies. Our goal is to advance biomolecular diagnosis and imaging using small silver clusters comprised of ~10 atoms with strong emission in the near-infrared spectral region where biological samples are relatively transparent. These metallic ligands associate with oligonucleotide sensors that integrate two distinct functions: the formation of specific silver clusters via nucleobase coordination within prescribed sequences and the recognition of target oligonucleotides through complementary base pairing. Confident and highly sensitive detection is accomplished when hybridization of the analyte with this sensor transforms a cluster from a nonemissive state with a violet absorption to a highly emissive state with near-infrared absorption. These sensors are distinguished by their strong and photostable fluorescence response and their economical, convenient, and modular synthesis, thus opening this methodology to a diversity of applications. Our studies will focus on a range of microRNA sequences that are biomarkers for human diseases. The following synthetic, structural, and stability studies will provide the foundation to develop the full potential of this new sensing strategy. I. Optimizing reaction conditions and the sequence environments are critical steps towards forming and transforming specific silver clusters. Highly parallel sequence variations in conjunction with spectral analysis will be coupled with measurements of the cluster stoichiometry and oligonucleotide shape to design sensors that are appropriate for direct analysis in biological samples. II. These metallic chromophores are not only distinguished by their spectra but also by their active role in shaping the sensors. We have shown that a violet absorbing cluster folds its DNA hosts, and biochemical/chemical probes and fluorescent base analogs will be used to map the secondary structure of DNA hosts through solvent exposure of their nucleobases. By identifying where the clusters bind and how they impact the DNA structure, generalized sensors that incorporate cluster-induced folding will be developed. III. Because the cluster coordinates and folds its DNA hosts, hybridization of the target oligonucleotide is inhibited. This impediment will be exploited to make fine distinctions between oligonucleotides that have mismatched base pairs and thus have reduced affinities for a specific sensor. The spectral changes that accompany temperature induced unfolding will provide the quantitative thermodynamic basis for distinguishing such targets. With the structural and thermodynamic insight provided by the above studies, a novel signal amplification scheme based on sequential unfolding will be developed for the detection of low abundance species.

描述（由申请人提供）：荧光是一种强大的生物分析工具，但背景干扰可能需要大量纯化体外分析，并严重限制体内研究。我们的目标是利用由~10个原子组成的小银团簇，在生物样品相对透明的近红外光谱区域具有强发射，来推进生物分子诊断和成像。这些金属配体与寡核苷酸传感器相结合，整合了两种不同的功能：形成