SENSORS: Arrayed Optical Detection of Nanoscale Biomass

该传感器方案的重点是检测少量物质的能力，包括致病菌和对细胞反应不可或缺的生物分子。对质量变化的传感问题和片上复用与解复用问题提出了新的解决方法。这些想法是基于先进的MEMS和集成光学器件开发的概念。目前大多数检测技术要么体积庞大，要么价格昂贵，要么速度缓慢。我们提出了一种用于超灵敏检测材料分子量的新型装置/仪器，可用于病原体和生化检测，医学，药物发现和纳米技术。所提出的技术允许通过光纤连接结构检测内在网络结构中的不同目标阵列。该技术通过使用一次性无源芯片，以低成本实现高通量。该器件由基于绝缘体上硅的芯片组成，该芯片结合了超灵敏的纳米机械悬臂和新型的基于硅的无源集成光学器件。无源光环谐振器用于光信号的片上复用和解复用。环形谐振器作为不同波长的滤波器，被引导到不同的悬臂式传感器。悬臂波导用于运动检测。兆赫兹范围内的机械振动由一组生物敏化悬臂换能器的一个元件在光学信号上编码。单个波长与不同悬臂式传感器的机械振动的一对一关联允许人们解决每个传感点。这种转导策略的创新允许使用不需要外部调谐或闭环控制的环形谐振器。此外，这种策略需要廉价的宽带光载波信号源。每个环形谐振器/悬臂对的振动频率位移可以在外部装置上并行检测。生物传感器的工作原理是基于高度敏感的免疫特异性病原体附着在硅纳米结构上。除了检测病原体的存在外，还测量病原体的质量。我们的初步结果表明，悬臂梁能够检测到图到皮图范围内的质量。质量的附加信息允许人们筛选假阳性，大大提高了方法的效率。集成电路兼容制造技术使一次性芯片的成本真正降到最低。从这种方法中产生的是高分辨率测量各种病原体干质量的可能性，从大型单细胞生物到病毒和大型大分子。这种新颖的基于硅的纳米光子运动检测方案允许这样的设备阵列形成一个完整的硅平台，以降低成本，提高灵敏度和巨大的系统级集成，革命性的功能，成本和便携性。更广泛的影响这项研究将使廉价的紧凑型测试能够大规模获得，目前仅在少数专业实验室进行。这将有助于预防和诊断当今的疾病和生物有害物质。例如，我们可以设想，战场上的士兵在口袋里携带传感器，探测到生物战中使用的非常微小的危险化学品痕迹，或者在医生办公室或家中，病人自己使用一次性传感器，对疾病进行极其敏感的监测。

AbstractIntellectual MeritThis Sensor proposal focuses on the ability to detect small amounts of materials, including pathogenic bacteria and biomolecules integral to cell responses. New approaches are proposed to the problems of transducing mass changes and to the problems of on-chip multiplexing and demultiplexing. These ideas are based on concepts developed for advanced MEMS and integrated optic devices. Most current detection technologies are either, bulky, expensive or slow. We propose a novel device/instrument for ultra-sensitive detection of molecular amounts of material with applications in pathogen and biochemical detection, medicine, drug discovery, and nanotechnology. The proposed technology allows the detection of an array of different targets in an intrinsically networked structure through fiber-optically linked structures. The technology lends itself to high throughput at low cost through use of disposable passive chips.The device consists of a silicon-on-insulator based chip that incorporates ultra-sensitive nano-mechanical cantilevers with novel silicon-based passive integrated optics. Passive optical ring-resonators are used for on-chip wavelength multiplexing and demultiplexing of optical signals. The ring-resonators act as filters for different wavelengths, which are guided to different cantilever sensors. The cantilever waveguide is used for motion detection. Mechanical vibrations in the MHz range are encoded on the optical signal by one element of an array of biosensitized cantilever transducers. The one-to-one association of individual wavelengths with mechanical vibrations of different cantilever sensors allows one to address each sensing site. This innovation in transduction strategy allows the use of ring-resonators that do not need external tuning or closed-loop control. Furthermore, this strategy requires inexpensive broadband sources for optical carrier signals. The sensed shift in vibration frequency at each ring resonator/cantilever pair can be detected in parallel on the external device. The principle of operation of the biosensor is based on highly-sensitive, immunospecific attachment of pathogens to silicon nanofabricated structures. In addition to detecting its presence, the mass of the pathogen is also measured. Our preliminary results show that the cantilevers are able to detect mass in the attograms to picograms range. The additional information of the mass allows one to screen for false positives, greatly increasing the efficiency of the method. The IC compatible fabrication technology allows the cost to be truly minimized for the disposable chip. Emerging from this method is the possibility of high resolution measurements of the dry mass of a great variety of pathogens, from large unicellular organisms to viruses and large macromolecules. This novel Si-based nanophotonic motion detection scheme allows arrays of such devices to form a complete silicon platform for reduced cost, increased sensitivity and enormous system level integration revolutionizing functionality, cost and portability.Broader ImpactsThis research will will enable large scale accessibility for inexpensive compact tests, today only done in a few specialized laboratories. This will help prevent and diagnose diseases and bio hazardous materials of today. One could envision for example the detection of very small traces of hazardous chemicals used in biowarfare by a soldier in the field, carrying the sensor in his pocket, or extremely sensitive monitoring of a disease, in the doctor's office or at home, by the patient himself using a disposable sensor.