Mass-based Flow Cytometry

描述(申请人提供)：虽然商用流式细胞仪能够实现高通量的颗粒分析，具有令人印象深刻的灵敏度，但它们在分析小颗粒方面的灵敏度有限。光散射对病毒的检测极限远低于现有的灵敏度，而且对某些类型的细菌的检测已被证明是困难的。此外，与其他基于微流控的样品提取和制备芯片的集成仍然很困难。该项目的目标是开发一种全新的流式细胞术方法，该方法基于测量生物成分流经悬浮微通道谐振器(SMR)时的质量。在传统的流式细胞术中，荧光标记的亲和分子(如抗体)使特定的成分(如细胞)比背景成分更亮，荧光标记的成分的数量是通过光学读出来确定的。在所提出的方法中，纳米颗粒亲和偶联物将使特定的组分比背景组分更重，并且纳米颗粒标记组分的数量将通过SMR加权来确定。我们最近已经证明，SMR可以在流动格式下以~1飞秒分辨率测量溶液中的质量。这样的分辨率比高端商用石英晶体微天平提高了六个数量级。或者，一毫微克相当于一个45纳米金纳米颗粒的质量，或者是溶液中大肠杆菌质量的百分之一。这项建议的总体目标是开发特定病毒和细胞的聚集分析，并验证SMR在量化聚集程度和目标浓度方面的性能。我们预计，SMR的纳米级分辨率，再加上其健壮性、低成本和微流控格式，将使基于质量的流式细胞术成为研究环境中的有用工具。

DESCRIPTION (provided by applicant): While commercial flow cytometers enable high-throughput particle analysis with impressive sensitivity, they have limited sensitivity for analyzing small particles. The detection limit for viruses by light scattering is well below the existing sensitivity, and the detection of certain types of bacteria has proven to be difficult. Furthermore, integration with other microfluidic-based sample extraction and preparation chips remains difficult. The goal of this project is to develop a fundamentally new approach for flow cytometry that is based on measuring the mass of biological components as they flow through a suspended microchannel resonator (SMR). In conventional flow cytometry, fluorescently labeled affinity molecules (e.g. antibodies) make specific components (e.g. cells) brighter than the background ones, and the number of fluorescently labeled components is determined with optical readout. In the proposed approach, nanoparticle-affinity conjugates will make specific components heavier than the background ones, and the number of nanoparticle labeled components will be determined by weighing them with the SMR. We have recently demonstrated that the SMR can measure mass in solution with ~1 femtogram resolution in a flow-through format. Such a resolution represents a six order of magnitude improvement over a high-end commercial quartz crystal microbalance. Alternatively, one femtogram is equivalent to the mass of a 45 nm gold nanoparticle, or one percent of the mass of an E. coli bacterium in solution. The overall goal of this proposal is to develop aggregation assays for specific viruses and cells, and to validate the performance of the SMR for quantifying the degree of aggregation and hence target concentration. We envision that the nanoscale resolution of the SMR coupled with its robustness, low-cost, and microfluidic format will make mass-based flow cytometry a useful tool for the research environment.