Ultrasensitive Nanoscale Magnetic Sensors for Label-free Analysis of Cancer

描述（由申请人提供）：在这份重新提交的针对癌症分子分析创新技术（FOA CA-07-033）的申请中，我们寻求开发一种新型传感器技术，该技术利用新兴的纳米级稀释磁性半导体（DMS）材料，实现对DNA分子的超灵敏无标记电检测，用于癌症的遗传分析。传感机制如下：适当生物功能化的DMS纳米材料的半导体特性在目标分子与表面探针分子的特定结合时被表面电荷调制，这导致显著的磁性变化，可以使用计算机硬盘中发现的高灵敏度巨磁电阻（GMR）磁场传感器检测到。该传感器的性能优于目前的任何技术，具有简单、特异、高通量、鲁棒性、与高密度阵列和多路复用的潜在兼容性，并且具有低成本和大规模可制造性的潜力。在本应用中，我们将演示原理验证操作，并使用两个DMS纳米材料家族和来自p53基因的模型DNA样本验证所提出传感器的极高灵敏度。具体步骤为：1)合成并表征过渡金属掺杂ZnO和掺杂cr的ZnTe纳米材料，并在室温附近表现出强大的铁磁性；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表面，作为拟议传感器的传感元件；3)利用SQUID磁力计演示并理解p53基因互补寡核苷酸作用于表面修饰纳米材料后磁性能的变化；4)使用商用GMR设备构建集成传感器设备，并使用目标寡核苷酸的模型分析物演示原理验证实时电传感测量；5)评估和量化传感器对DNA浓度的响应，证明在0.1飞摩尔（femtomolar, fM）浓度下可以检测到互补目标p53寡核苷酸，并通过优化传感器在10飞摩尔（femtomolar, fM）浓度下区分野生型和单核苷酸错配突变型p53。该项目的成功将使廉价的桌面甚至手持式交钥匙电子设备成为可能，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分析，以检测和诊断癌症，监测癌症进展，并确定对治疗的反应，只需在护理点设置中进行少量培训和样品制备。

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.