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”的新R21申请。“主要目标是开发一种新形式的微到纳米尺度的生物分子相互作用分析，如DNA-DNA，蛋白质-蛋白质和蛋白质-DNA;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十字架，这是一种磁传感技术，最近已经达到了我们可以在生物医学应用中使用的程度。一个跨学科的研究小组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)通过微霍尔磁力测定法与市售磁珠证明选择性DNA杂交;将通过多个磁性颗粒的序列特异性结合（每个颗粒均通过多个DNA-DNA连接）确定可行性。(2)开发和测试纳米级格式的霍尔磁强计;通过平行开发磁性纳米颗粒和霍尔磁强计的进一步小型化，将提高测定的灵敏度和信噪比。纳米颗粒的组成和尺寸将被改变以优化霍尔器件的输出。(3)通过霍尔磁力测定法实验确定生物分子检测的限度;将使用目标2中的纳米级霍尔十字和磁性颗粒检测序列特异性DNA杂交。具有最佳组成和尺寸的纳米颗粒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。将在分析物的稀释溶液中进一步测试产生霍尔磁力测定法和序列特异性DNA杂交的信噪比的最佳组合的纳米颗粒，以确定检测限。纳米尺度的磁感应预计用于检测少量的分析物分子-一个或两个分子的限制，需要单细胞分析。此外，磁传感测定可用于确定一些酶如核酸酶和蛋白酶的活性，可能在单分子水平上。该格式还应该适合于确定双链DNA的解链温度，同样可能在单分子水平上。磁感应也与磁控制系统兼容，打开了控制（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.