Micro-Hall magnetometry for detection of bio-molecular interactions

描述（由申请人提供）：这是响应PAR-03-045“生物学和医学中的纳米科学和纳米技术”的一项新的R21申请。主要目标是为生物分子相互作用（如DNA-DNA、蛋白质-蛋白质和蛋白质- dna）开发一种新的微到纳米级检测方法；我们专注于这个R21项目的序列特异性DNA杂交。这些检测将利用高灵敏度霍尔交叉，这是一种最近才达到我们可以在生物医学应用中使用的磁传感技术。一个跨学科的研究团队将通过高风险/高回报的三个具体目标的研究来实现这一目标。(1)利用市售磁珠进行微霍尔磁强计，演示选择性DNA杂交；可行性将通过多个磁性颗粒的序列特异性结合来建立，每个磁性颗粒通过多个DNA-DNA连接。(2)开发和测试纳米级格式霍尔磁力计；磁纳米粒子的平行发展和霍尔磁力计的进一步小型化将提高检测的灵敏度和信噪比。纳米颗粒的组成和大小将会改变，以优化霍尔装置的输出。(3)实验确定霍尔磁强计检测生物分子的极限；序列特异性DNA杂交检测将使用纳米级霍尔杂交和Aim 2的磁性颗粒进行测试。具有最佳组成和大小的纳米粒子将首先测试其与生物分子功能化（DNA附着）和序列特异性杂交的兼容性。为霍尔磁强计和序列特异性DNA杂交提供最佳信噪比组合的纳米颗粒将在分析物的稀释溶液中进一步测试，以确定检测限。纳米尺度的磁感测有望用于检测少量的分析物分子——单细胞分析所需的一个或两个分子的极限。此外，磁传感检测可以用于确定一些酶的活性，如核酸酶和蛋白酶，可能在单分子水平上。这种格式也应该适用于确定双链DNA的熔化温度，同样可能是在单分子水平上。磁感测也与磁控系统兼容，开启了控制（通过外部施加的电磁场）附着在珠子上的生物分子位置的可能性。

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.