Observations of Tunable Resistive Pulse Sensing for Exosome Analysis: Improving System Sensitivity and Stability
Observations of Tunable Resistive Pulse Sensing for Exosome Analysis: Improving System Sensitivity and Stability
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DOI：
10.1021/acs.langmuir.5b01402
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发表时间：
2015-06-16
期刊：
影响因子：
3.9
通讯作者：
Trau, Matt
中科院分区：
文献类型：
--
作者：
Anderson, Will;Lane, Rebecca;Trau, Matt
外泌体的大小分布和浓度测量在研究其细胞功能和摄取时是必不可少的。最近，被称为可调电阻脉冲传感（TRPS）的粒度分布和浓度测量平台已经越来越多地用于外泌体样品的表征。TRPS测量单个亚微米/纳米级颗粒在穿过嵌入弹性膜中的尺寸可调的亚微米/微米尺寸的孔时产生的电阻（电阻脉冲）的短暂增加。不幸的是，TRPS测量容易受到系统稳定性问题和灵敏度问题的影响，其中系统稳定性问题是孔可能被颗粒堵塞，而灵敏度问题是颗粒太小而无法在系统的背景噪声中检测到。在这里，我们提供了一个全面的分析TRPS外泌体测量所涉及的参数，并证明了通过优化系统参数来提高系统灵敏度和稳定性的能力。我们还提供了第一次分析系统噪声，灵敏度截止限，和准确度相对于外来体测量，并提供了一个明确的定义系统灵敏度，表明可以检测到的跨膜电流的噪声内的最小粒子直径。还提供了来自TRPS和冷冻电子显微镜的外泌体尺寸测量的比较，发现大量较小的外泌体低于TRPS平台的检测限，并提供了一种潜在的见解，即为什么文献中报道的外泌体尺寸分布存在如此大的变异性。我们相信这里报道的观察结果可以帮助其他人改进外泌体样品和其他亚微米生物和非生物颗粒的TRPS测量。
Size distribution and concentration measurements of exosomes are essential when investigating their cellular function and uptake. Recently, a particle size distribution and concentration measurement platform known as tunable resistive pulse sensing (TRPS) has seen increased use for the characterization of exosome samples. TRPS measures the brief increase in electrical resistance (a resistive pulse) produced by individual submicrometer/nanoscale particles as they translocate through a size-tunable submicrometer/micrometer-sized pore, embedded in an elastic membrane. Unfortunately, TRPS measurements are susceptible to issues surrounding system stability, where the pore can become blocked by particles, and sensitivity issues, where particles are too small to be detected against the background noise of the system. Herein, we provide a comprehensive analysis of the parameters involved in TRPS exosome measurements and demonstrate the ability to improve system sensitivity and stability by the optimization of system parameters. We also provide the first analysis of system noise, sensitivity cutoff limits, and accuracy with respect to exosome measurements and offer an explicit definition of system sensitivity that indicates the smallest particle diameter that can be detected within the noise of the trans-membrane current. A comparison of exosome size measurements from both TRPS and cryo-electron microscopy is also provided, finding that a significant number of smaller exosomes fell below the detection limit of the TRPS platform and offering one potential insight as to why there is such large variability in the exosome size distribution reported in the literature. We believe the observations reported here may assist others in improving TRPS measurements for exosome samples and other submicrometer biological and nonbiological particles.