Departments of Biological Engineering, Materials Science and Engineering, Electrical Engineering and Computer Science, and Mechanical Engineering, Koch Institute for Integrative Cancer Research, Computational and Systems Biology Initiative, Harvard-MIT Health Sciences and Technology, Institute for Medical Engineering and Science, and Microsystems Technology Laboratories, Massachusetts Institute of Technology, Cambridge, MA 02139.
Proc Natl Acad Sci U S A. 2014 Jan 28;111(4):1310-5. doi: 10.1073/pnas.1318602111. Epub 2014 Jan 13.
Physical characterization of nanoparticles is required for a wide range of applications. Nanomechanical resonators can quantify the mass of individual particles with detection limits down to a single atom in vacuum. However, applications are limited because performance is severely degraded in solution. Suspended micro- and nanochannel resonators have opened up the possibility of achieving vacuum-level precision for samples in the aqueous environment and a noise equivalent mass resolution of 27 attograms in 1-kHz bandwidth was previously achieved by Lee et al. [(2010) Nano Lett 10(7):2537-2542]. Here, we report on a series of advancements that have improved the resolution by more than 30-fold, to 0.85 attograms in the same bandwidth, approaching the thermomechanical noise limit and enabling precise quantification of particles down to 10 nm with a throughput of more than 18,000 particles per hour. We demonstrate the potential of this capability by comparing the mass distributions of exosomes produced by different cell types and by characterizing the yield of self-assembled DNA nanoparticle structures.
纳米颗粒的物理特性表征对于广泛的应用是必需的。纳米机械谐振器可以定量测量单个颗粒的质量，其检测极限在真空中可达到单个原子。然而，由于在溶液中的性能严重下降，其应用受到限制。悬浮微纳通道谐振器为在水相环境中的样品实现真空级精度开辟了可能性，Lee 等人之前已经实现了 1-kHz 带宽下的 27 飞克等效质量分辨率[（2010）Nano Lett 10（7）：2537-2542]。在这里，我们报告了一系列进展，将分辨率提高了 30 多倍，在相同带宽下达到 0.85 飞克，接近热机械噪声极限，并能够以超过 18000 个/小时的通量对 10nm 以下的颗粒进行精确量化。我们通过比较不同细胞类型产生的外泌体的质量分布，并通过表征自组装 DNA 纳米颗粒结构的产率，证明了这种能力的潜力。
