Micro-Hall magnetometry for detection of bio-molecular interactions

描述(申请人提供)：这是一个新的R21申请，以回应PAR-03-045“生物和医学中的纳米科学和纳米技术”。主要目标是开发一种新的微纳尺度分析方法，用于DNA-DNA、蛋白质-蛋白质和蛋白质-DNA等生物分子的相互作用；在这个R21项目中，我们专门专注于序列特异性DNA杂交。这些分析将利用高灵敏度的霍尔十字，这是一种磁传感技术，最近我们可以将其用于生物医学应用。一个跨学科的研究团队将通过对三个具体目标的高风险/高回报研究来实现这一目标。(1)用市售磁珠通过微霍尔磁测法演示选择性DNA杂交；将通过多个磁性颗粒的序列特定结合来确定可行性，每个磁性颗粒通过多个DNA-DNA连接。(2)研制和测试纳米格式霍尔磁强计；通过平行开发磁性纳米粒子和进一步小型化霍尔磁强计，将提高分析的灵敏度和信噪比。纳米颗粒的组成和尺寸将会改变，以优化霍尔器件的输出。(3)从实验上确定霍尔磁测法检测生物分子的极限；序列特异性DNA杂交的检测将使用Aim 2的纳米霍尔十字和磁性颗粒。具有最佳组成和大小的纳米颗粒将首先测试与生物分子功能化(DNA附着)和序列特异性杂交的兼容性。为霍尔磁学和序列特异性DNA杂交产生最佳信噪比组合的纳米粒子将在分析物的稀溶液中进一步测试，以确定检测极限。纳米级磁传感有望用于检测少量分析物分子--单细胞分析所需的极限分子中的一到两个分子。此外，磁感应分析可以用来确定某些酶的活性，如核酸酶和蛋白酶，可能是在单分子水平上。该格式还应该能够确定双链DNA的熔化温度，同样可能是在单个分子的水平上。磁感应也与磁控系统兼容，为(通过外部施加的电磁场)控制附着在珠子上的生物分子的位置打开了可能性。

DESCRIPTION (provided by applicant): This is a new R21 application in response to PAR-03-045 "Nanoscience and Nanotechnology in Biology and Medicine." The major goal is to develop a new format of micro- to nano-scale assays for biomolecular interactions such as DNA-DNA, protein-protein, and protein-DNA; we focus exclusively on sequence-specific DNA hybridization for this R21 project. These assays will utilize high-sensitivity Hall crosses, a magnetic sensing technology that has very recently reached the point where we can pursue its use in biomedical applications. An interdisciplinary research team will accomplish this goal through high-risk/high-reward research on three specific aims. (1) Demonstrate selective DNA hybridization by micro-Hall magnetometry with commercially available magnetic beads; feasibility will be established through sequence-specific binding of multiple magnetic particles, each via multiple DNA-DNA linkages. (2) Develop and test nano-scale format Hall magnetometers; sensitivity and signal-to-noise of the assay will be improved upon by parallel development of magnetic nano-particles and further miniaturization of the Hall magnetometer. Nano-particle composition and size will be varied to optimize output of the Hall device. (3) Determine experimentally the limits of bio-molecular detection by Hall magnetometry; detection of sequence-specific DNA hybridization will be tested using the nano-scale Hall crosses and magnetic particles from Aim 2. Nano-particles with optimal composition and size for magnetometry will be tested first for compatibility with bio-molecule functionalization (DNA attachment) and sequence-specific hybridization. Nano-particles that yield optimal combinations of signal-to-noise for Hall magnetometry and sequence-specific DNA hybridization will be tested further in dilute solutions of analyte to determine the limit of detection. Nano-scale magneto-sensing is anticipated for detection of a small number of analyte molecules-one or two molecules in the limit as are needed for single cell analyses. Further, magneto-sensing assays could be used to determine activity of some enzymes such as nucleases and proteases, possibly at the single molecule level. The format should also be amenable to determining the melting temperature for double stranded DNA, again perhaps at the level of a single molecule. Magneto-sensing is also compatible with magneto-control systems, opening up the possibility of controlling (via an externally applied electromagnetic field) the location of bio-molecules attached to beads.