Whispering Gallery Mode Carousel: A means for Enhanced Detection in Biosensing and Surface-Force Probing

回音壁模式旋转木马：生物传感和表面力探测中增强检测的方法

• 批准号: 0933531
• 负责人: Stephen Arnold
• 金额: --
• 依托单位: Polytechnic University of New York
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-15 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0933531&HistoricalAwards=false
• 关键词: Whispering; Gallery; Mode; Carousel; means

0933531ArnoldVirus particles are a major cause for human disease, and their early detection and identification is of increasing importance as air travel allows these infectious agents to spread rapidly to populations across the globe. A fast detector that is sensitive to a single virus particle by determining its genus and size would answer the demand for early detection. The present proposal is to continues the investigation into microsphere whispering gallery mode (WGM) biosensors for early detection of viruses in human fluids as we utilize a recently discovered phenomenon of light trapping of nanoparticles within the WGM evanescent volume. The sensing is based on the extremely narrow photonic resonances of microspheres that shift their frequencies as a result of an environmental change. Within the reach of the WGM?s evanescent field (~ 200 nm) nanoparticles are drawn toward the surface by gradient forces, similar to those present in optical tweezers. A trapping potential-well is formed by an attractive evanescent polarization potential, repulsive electrostatic potential, and van der Waals potential. In the case of a low binding-affinity or a low density of binding sites, nanoparticles are propelled around in orbit by radiation pressure. This trapping mechanism (WGM Carousel) along with controlled binding-affinity adds additional functionality and assures high sensitivity and specificity to the WGM biosensor. The ultimate goal is to build microfluidic biosensors that are sensitive to a single viral particle and can differentiate virions according to their size/mass and affinity to specific antibodies. The small size of these bio-particles demands micrometer-size sensors3. However Brownian diffusion of ultra-low concentration analytes crossing the boundary layer is considered a major hurdle4 for miniature sensors. Preliminary results show that the WGM Carousel sensor can have significantly enhanced transport rates ( 50×) of particles to the sensing region, compared to other miniature sensors. In addition the carousel mechanism provides a means for investigating forces arising near the surface. Understanding these forces is of great importance for the design of microfluidic devices and micro-fabrication. Nanoparticles trapped in a WGM carousel can be used to quantitatively measure surface interactions from their stochastic radial motion. By proper choice of the interacting surfaces and the liquid medium it will be possible to screen the electrostatic repulsion and reveal short range interactions such as van der Waals. There are challenges for the DLVO (the theory of colloidal stability) to properly describe the interactions at very short range (5nm) for various aqueous solutions, where repulsive solvation forces are observed. WGM Carousel will help address these challenges.

阿诺德病毒颗粒是人类疾病的主要原因，由于航空旅行使这些传染性病原体能够在全球人群中迅速传播，因此对它们的早期发现和识别越来越重要。通过确定病毒的种类和大小对单个病毒粒子敏感的快速检测器将满足早期检测的需求。目前的建议是继续研究微球窃窃廊模式（WGM）生物传感器，用于人体体液中病毒的早期检测，因为我们利用了最近发现的纳米颗粒在WGM消失体积内的光捕获现象。这种传感是基于微球的极窄光子共振，由于环境变化而改变其频率。在WGM的范围内？S倏逝场（~ 200nm）纳米粒子被梯度力吸引到表面，类似于光镊中存在的力。捕获势阱是由有吸引力的倏逝极化势、有排斥的静电势和范德华势组成的。在低结合亲和力或低结合位点密度的情况下，纳米粒子在辐射压力的推动下在轨道上运动。这种捕获机制（WGM Carousel）以及控制的结合亲和力增加了额外的功能，并确保了WGM生物传感器的高灵敏度和特异性。最终目标是建立对单个病毒颗粒敏感的微流体生物传感器，并可以根据病毒粒子的大小/质量和对特定抗体的亲和力来区分病毒粒子。这些微小的生物颗粒需要微米级的传感器。然而，超低浓度分析物穿过边界层的布朗扩散被认为是微型传感器的主要障碍。初步结果表明，与其他微型传感器相比，WGM旋转木马传感器可以显著提高粒子到传感区域的传输速率（50倍）。此外，旋转装置提供了一种方法来研究在表面附近产生的力。了解这些力对微流控器件的设计和微加工具有重要意义。被困在WGM旋转木马中的纳米粒子可用于定量测量其随机径向运动中的表面相互作用。通过对相互作用表面和液体介质的适当选择，可以屏蔽静电斥力并揭示范德华等短程相互作用。DLVO（胶体稳定性理论）在很短的范围内（5nm）正确地描述各种水溶液的相互作用是一个挑战，在这种情况下，可以观察到排斥溶剂化力。WGM Carousel将有助于应对这些挑战。