Ultrasensitive Nanoscale Magnetic Sensors for Label-free Analysis of Cancer

描述(申请人提供)：在这份回应癌症分子分析创新技术(FOACA-07-033)的重新提交的申请中，我们寻求开发一种新型的传感器技术，该技术利用新兴的纳米级稀磁半导体(DMS)材料来实现对用于癌症基因分析的DNA分子的超灵敏无标记电检测。其传感机制如下：适当生物功能化的DMS纳米材料的半导体性质受到目标分子与表面探针分子特定结合时表面电荷的调制，这导致了显著的磁性变化，使用计算机硬盘中的高灵敏度巨磁电阻(GMR)磁场传感器可以检测到这些变化。该传感器的性能优于任何现有技术，具有简单、专一、高吞吐量、坚固耐用、可与高密度阵列和多路传输兼容、低成本和良好的大规模可制造性等特点。在这个应用中，我们将演示原理证明操作，并使用两个DMS纳米材料家族和来自P53基因的模型DNA样本来验证所提出的传感器的极高灵敏度。具体步骤是：1)合成和表征过渡金属掺杂的氧化锌和铬掺杂的锌镉纳米材料，并在室温附近表现出良好的铁磁性；2)开发和优化策略，将合适的寡核苷酸附着在这些纳米材料的表面作为传感器的传感元件；3)使用SQUID磁强计演示和了解将来自p53基因的互补目标寡核苷酸应用于表面修饰的纳米材料时磁性的变化；4)使用商用GMR器件构建集成的传感器器件，并用目标寡核苷酸的模型分析物演示原理验证的实时电传感测量；5)评价和量化传感器对DNA浓度的响应，通过传感器的优化，可以检测到浓度为0.1毫微摩尔(Fm)的互补靶标P53寡核苷酸，以及浓度为10fM的野生型和单核苷酸错配突变体P53的区分。该项目的成功将使廉价的台式甚至是手持交钥匙电子设备能够使医疗保健专业人员能够对尿液、血清和血液样本进行强大的高通量但高灵敏度的分析，用于检测和诊断癌症、监测癌症进展以及确定治疗反应，而只需在护理地点设置很少的培训和样品准备。

DESCRIPTION (provided by applicant): In this resubmitted application responding to Innovative Technologies for Molecular Analysis of Cancer (FOA CA-07-033), we seek to develop a novel type of sensor technology that exploits the emerging nanoscale dilute magnetic semiconductor (DMS) materials to enable ultrasensitive label-free electrical detection of DNA molecules for genetic analysis of cancer. The sensing mechanism is the following: the semiconducting properties of the properly biofunctionalized DMS nanomaterials are modulated by surface charges upon specific binding of target molecules to surface probe molecules, which leads to significant magnetic property changes that can be detected using highly sensitive giant magnetoresistance (GMR) magnetic field sensors found in computer hard disks. Outperforming any current technologies, the proposed sensors promise to be simple, specific, high throughput, robust, potentially compatible with high density arrays and multiplexing, and potentially boast low cost and good manufacturability on a large scale. In this application, we will demonstrate the proof-of-principle operation and validate the extremely high sensitivity of the proposed sensors using two families of DMS nanomaterials and model DNA samples from the p53 gene. The specific steps are: 1) synthesize and characterize nanomaterials of transition metal doped ZnO and Cr-doped ZnTe, and demonstrate robust ferromagnetism near room temperature; 2) develop and optimize strategies to attach suitable oligonucleotides onto the surface of these nanomaterials for use as the sensing elements of proposed sensors; 3) demonstrate and understand the magnetic property changes upon applying complementary target oligonucleotides from p53 genes to surface modified nanomaterials using a SQUID magnetometer; 4) construct integrated sensor devices using commercial GMR devices, and demonstrate proof-of-principle real-time electrical sensing measurements with model analytes of target oligonucleotides; and 5) evaluate and quantify the sensor response versus DNA concentrations and demonstrate the detection of complementary target p53 oligonucleotide down to concentration of 0.1 femtomolar (fM), and the differentiation of wild type and single nucleotide mismatched mutant p53 at the concentration of 10 fM through the optimization of sensors. The success of this project will enable inexpensive table-top or even handheld turn-key electrical devices that will allow heathcare professionals to perform robust high throughput but yet highly sensitive analysis of urine, serum, and blood samples for the detection and diagnosis of cancer, the monitoring of cancer progression, and the determination of response to therapy with little training and sample preparation in point-of-care settings.