Ultrasensitive, Label-free Silicon Nanowire Biosensing Arrays

描述（由申请人提供）：NIH第一阶段SBIR提案旨在开发和商业化硅纳米线（SiNW）传感器平台，用于多路复用，无标签，生物传感应用。这个单一的平台将提供超灵敏、高特异性的实时检测，通过使用肽核酸（PNA）或核酸适体捕获探针功能化的可寻址NW阵列，可以对广泛的生物物种进行检测。它将提供廉价的电子生物检测，而目前最先进的生物分析物检测需要昂贵的实验室设备和训练有素的专家。在这些传感器中，sinw充当场效应晶体管（FET）结构中的栅极，PNA探针（基因组靶）杂交并捕获互补的单链DNA。适体探针通过选择过程产生并固定，在那里它们从溶液中捕获其他靶向剂（例如蛋白质，毒素，细胞）。在SiNW表面捕获的试剂会产生SiNW电导率的变化，允许使用标准信号处理进行多路检测和分析。半导体纳米硅的可调谐导电特性，加上其表面结合分析物的能力，使得纳米硅在廉价、敏感的电子生物传感器应用中特别有吸引力，并且已经取得了多次成功。互补PNA与DNA结合具有很高的亲和力和特异性，适配体具有高的目标亲和力和特殊的特异性，允许在同一反应室中检测多种分析物。这种特殊的结合精度使更完整的样品分析和有利于诊断，例如肿瘤学（蛋白质和DNA生物标志物）和食品污染（病原体细胞和产毒产物）。PNA和适体固定化学已经建立，二氧化硅（因此SiNW）底物是表面修饰的理想选择。多个SiNW阵列（集成到同一电路中）将通过多个PNA/适体探针实现功能化，每个阵列将在硬件/软件中单独寻址，使捕获的分析物易于通过其匹配地址识别。大多数SiNW研究都是基于“自下而上”和“自上而下”过程的结合，并且在集成方面存在困难，需要精细的单个纳米结构的转移和定位。其他困难包括控制NW掺杂和接触电阻。该提案将使用纳米压印光刻（NIL）制造方法将生物传感器集成到高密度硅电路中，排除了单个sinw的运输，对准和布线，克服了掺杂和接触电阻问题，降低了制造成本，增加了商业化潜力。我们在第一阶段提案的目标是证明制造超灵敏、实时、无标签的纳米级传感器的可能性，这种传感器可以经济地生产，并且很容易与现成的信号处理组件集成。我们期待大量的商业化机会和投资回报。公共卫生相关性：这种SiNW生物传感器阵列的成功商业化将使医疗和卫生界能够提供高质量的疾病和癌症诊断，提供比所有现有标准更便宜、更快和更敏感的结果。它将有助于防止传染病（如大流行性流感）的传播，可用于进行食品和水安全检测，并有助于阻止耐抗生素微生物的传播。

DESCRIPTION (provided by applicant): This NIH Phase I SBIR proposal aims to develop and commercialize a silicon nanowire (SiNW) sensor platform for multiplexed, label-free, biosensing applications. This single platform will provide ultrasensitive, highly specific real-time detection of a wide range of biological species by using addressable NW arrays functionalized with peptide nucleic acid (PNA) or nucleic acid aptamer capture probes. It will provide inexpensive electronic biodetection, whereas current state-of-the-art detection of biological analytes requires expensive laboratory-based equipment and highly trained specialists. In these sensors, the SiNWs act as the gate electrode in a field-effect transistor (FET) configuration and the PNA probes (genomic target) hybridize and capture complementary single-stranded DNA. The aptamer probes are generated by a selective process and immobilized, where they capture other targeted agents (e.g. proteins, toxins, cells) from solution. Captured agents at the SiNW surface generate a change in SiNW electrical conductance, allowing multiplexed detection and analysis using standard signal processing. The tunable conducting properties of semiconducting NWs combined with the ability to bind analytes on their surface makes SiNWs particularly attractive for cheap, sensitive electronic biosensor applications, and they have shown repeated success. Complementary PNA binds to DNA with great affinity and specificity, and aptamers exhibit high target affinity and exceptional specificity, allowing for detection of multiple analytes in the same reaction chamber. This exceptional binding precision enables more complete sample analyses and benefits diagnostics in, for example, oncology (protein and DNA biomarkers) and food contamination (pathogen cells and toxigenic products). PNA and aptamer immobilization chemistry is well-established, and silica (and thus SiNW) substrates are ideal for surface modification. Multiple SiNW arrays (integrated into the same circuit) will be functionalized with multiple PNA/aptamer probes, and each array will be individually addressable in hardware/software, making captured analytes easily identifiable through their matching address. Most SiNW studies have been based on a combination of "bottom-up" and "top-down" processes and have difficulties with integration, requiring delicate transfer and positioning of individual nanostructures. Other difficulties include controlling NW doping and contact resistance. This proposal will use a nanoimprint lithography (NIL) fabrication method for integrating biosensors into high-density Si circuits that excludes transporting, aligning and wiring individual SiNWs and overcomes the doping and contact resistance issues, decreasing manufacturing costs and increasing commercialization potential. Our goal in this Phase I proposal is to demonstrate the possibility of fabricating ultrasensitive, real-time, label-free, nanoscale sensors that can be economically produced and easily integrated with off-the-shelf signal processing components. We anticipate substantial commercialization opportunities and return on investment. PUBLIC HEALTH RELEVANCE: Successful commercialization of this SiNW biosensor array will allow the medical and health community to offer high-quality disease and cancer diagnostics that provide cheaper, faster and more sensitive results than all current standards. It will help guard against the spread of infectious diseases (e.g., pandemic flu), can be deployed to perform food and water safety testing, and can help arrest the propagation of antibiotic-resistant microorganisms.