BIOSENSOR ARRAYS BASED ON SINGLE WALL CARBON NANOTUBES

蛋白质和细菌的灵敏检测在生物医学研究中至关重要， 应用于阐明疾病途径，免疫学，医学诊断，系统生物学，功能 蛋白质组学和新药开发。高选择性和灵敏度的结合测定阵列正日益受到重视。 鉴于生物医学科学的新兴领域和世界生物恐怖主义的加剧，这一点非常重要。灵敏，迅速， 生物和环境样品中蛋白质、细菌和毒素的特异性、多重检测， 对公众健康至关重要。该提案的广泛，长期目标是高度发展 使用图案化单壁碳的用于蛋白质和细菌的灵敏的微和纳米生物传感器阵列 纳米管（SWNTs）和生物分子识别元件。主要的具体应用包括同时 用于早期癌症检测的血清中的蛋白质生物标志物组的测量。 直径约为1.4 nm的单壁碳纳米管（SWNTs）具有世界上最高的导电性 并且具有用于生物分子的电感测的优异潜力。我们已经组装了~30 纳米长的碳纳米管呈20-200纳米直径束排列，称为带有电气连接的SWNT森林 导电表面。这些高表面积、可图案化的导电纳米结构提供了新的 高灵敏度生物传感器阵列的机会。在这个项目中，我们将联合收割机 通过对蛋白质和细菌的抗体的特异性分子识别进行转导。单壁碳纳米管作为分子 导线将在其尖端的酶标记和外部电连接之间矢量地穿梭电子。 我们在这里集中在过氧化物酶联安培免疫分析，其中酶催化还原的 H2 O2提供经由SWNT传输的电信号。在前期工作中，我们将抗体 SWNT森林，并实现了几种抗原的检测在ng/mL范围内和以下。使用新 开发了纳米管、过氧化物酶和二抗（Ab 2）的缀合物，其具有高的Ab 2标记 与SWNT免疫传感器的比率，我们最近检测到前列腺特异性抗原（PSA）在人血清中 0.01 ng/mL（0.25 Fmol/mL），检测限优于PSA的最佳商业测定。超低 NSB结合导电聚合物布线的纳米管结，沿着带有多酶标记 战略，承诺尽可能高的灵敏度。因此，我们将优化新的Ab 2纳米缀合物， 探索导电聚合物布线策略，并通过以下方式消除干扰的非特异性结合（NSB） 竞争性吸附的蛋白质/表面活性剂添加剂和新型低NSB有机表面的合成 nanotube ends.最后，我们将优化的制造/检测方法集成到多分析物传感器中 利用图案化的SWNT-抗体组装的阵列。除了实现我们的具体目标外，该项目 应该为各种各样的敏感微阵列装置的制造提供基本指导， 生物医学应用

Sensitive detection of proteins and bacteria is of central importance in biomedical research, with applications to elucidating disease pathways, immunology, medical diagnostics, systems biology, functional proteomics, and new drug development. Highly selective and sensitive binding-assay arrays are increasingly important in light of emerging areas of biomedical science and intensified world bioterrorism. Sensitive, rapid, specific, multiple detection of proteins, bacteria and toxins in biological and environmental samples is critically important for public health. The broad, long term goals of this proposal are to develop highly sensitive micro- and nano-biosensor arrays for proteins and bacteria using patterned single-walled carbon nanotubes (SWNTs) and biomolecule recognition elements. Major specific applications include simultaneous measurement of suites of protein biomarkers in serum for early cancer detection. Single walled carbon nanotubes (SWNTs) with ~1.4 nm diameters have the world's highest conductivity per unit mass and have excellent potential for electrical sensing of biomolecules. We have assembled ~30 nm long carbon nanotubes standing in 20-200 nm diameter bundles called SWNT forests with electrical links to conductive surfaces. These high surface area, patternable, conductive nanostructures provide new opportunities for highly sensitive biosensor arrays. In this project, we combine nanotube electrical transduction with specific molecular recognition of antibodies for proteins and bacteria. SWNTs as molecular wires will shuttle electrons vectorially between enzyme labels at their tips and external electrical connections. We focus here on peroxidase-linked amperometric immunoassays, in which enzyme catalyzed reduction of H2O2 provides electrical signals transmitted via SWNTs. In preliminary work, we attached antibodies to SWNT forests and achieved detection of several antigens in the ng/mL range and below. Using newly developed conjugates of nanotubes, peroxidases and secondary antibodies (Ab2) with high label-to-Ab2 ratios with the SWNT immunosensors, we recently detected prostate specific antigen (PSA) in human serum at 0.01 ng/mL (0.25Fmol/mL), a detection limit better than the best commercial assays for PSA. Ultra-low NSB combined with conductive polymer wiring of nanotube junctions, along with multi-enzyme label strategies, promise the highest possible sensitivity. Thus, we will optimize the new Ab2 nanoconjugates, explore conductive polymer wiring strategies, and eliminate non-specific binding (NSB)of interferences via competitively adsorbed protein/surfactant additives and synthesis of novel low NSB organic surfaces on nanotube ends. Finally, we will integrate optimized fabrication/detection approaches into multi-analyte sensor arrays utilizing patterned SWNT-antibody assemblies. In addition to achieving our specific aims, this project should provide fundamental guidance for fabrication of sensitive microarray devices for a wide variety of biomedical applications.