Material Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Proc Natl Acad Sci U S A. 2010 Dec 14;107(50):21306-10. doi: 10.1073/pnas.1016022107. Epub 2010 Nov 22.
Microscale mechanical forces can determine important outcomes ranging from the site of material fracture to stem cell fate. However, local stresses in a vast majority of systems cannot be measured due to the limitations of current techniques. In this work, we present the design and implementation of the CdSe-CdS core-shell tetrapod nanocrystal, a local stress sensor with bright luminescence readout. We calibrate the tetrapod luminescence response to stress and use the luminescence signal to report the spatial distribution of local stresses in single polyester fibers under uniaxial strain. The bright stress-dependent emission of the tetrapod, its nanoscale size, and its colloidal nature provide a unique tool that may be incorporated into a variety of micromechanical systems including materials and biological samples to quantify local stresses with high spatial resolution.
微尺度机械力可以决定从材料断裂部位到干细胞命运等重要结果。然而，由于当前技术的限制，绝大多数系统中的局部应力都无法测量。在这项工作中，我们提出了 CdSe-CdS 核壳四角纳米晶体的设计和实现，这是一种具有明亮发光读出的局部应力传感器。我们校准了四角纳米晶体对应力的发光响应，并利用发光信号报告了单根聚酯纤维在单轴应变下局部应力的空间分布。四角纳米晶体的这种明亮的、依赖于应力的发射、其纳米级尺寸以及其胶体性质提供了一种独特的工具，它可以被整合到各种微机械系统中，包括材料和生物样本中，以实现具有高空间分辨率的局部应力定量测量。
