Department of Chemistry, Clemson University, Clemson, South Carolina 29634, United States.
Department of Electrical and Computer Engineering, Clemson University, Clemson, South Carolina 29634, United States.
ACS Sens. 2020 Mar 27;5(3):711-718. doi: 10.1021/acssensors.9b01930. Epub 2020 Mar 6.
A luminescent spectral ruler was developed to measure micrometer to millimeter displacements through tissue. The spectral ruler has two components: a luminescent encoder patterned with alternating stripes of two spectrally distinct luminescent materials and an analyzer mask with periodic transparent windows the same width as the encoder stripes. The analyzer mask is placed over the encoder and held so that only one type of luminescent stripe is visible through the window; sliding the analyzer over the encoder modulates the luminescence spectrum acquired through the analyzer windows, enabling detection of small displacements without imaging. We prepared two types of spectral rulers, one with a fluorescent encoder and a second with an X-ray excited optical luminescent (XEOL) encoder. The fluorescent ruler used two types of quantum dots to form stripes that were excited with 633 nm light and emitted at 645 and 680 nm, respectively. Each ruler type was covered with chicken breast tissue to simulate implantation. The XEOL ruler generated a strong signal with negligible tissue autofluorescence but used ionizing radiation, while the fluorescence ruler used non-ionizing red light excitation but required spectral fitting to account for tissue autofluorescence. The precision for both types of luminescent spectral rulers (with 1 mm wide analyzer windows, and measured through 6 mm of tissue) was <2 μm, mostly limited by shot noise. The approach enabled high micrometer to millimeter displacement measurements through tissue and has applications in biomechanical and mechanochemical measurements (e.g., tracking postsurgical bone healing and implant-associated infection).
研制了一种用于测量组织内微米至毫米级位移的荧光光谱标尺。光谱标尺由两部分组成：一个用两种光谱上明显不同的发光材料交替条纹图案化的发光编码器，以及一个带有周期性透明窗口的分析器掩模，其宽度与编码器条纹相同。分析器掩模放置在编码器上，并保持只有一种类型的发光条纹通过窗口可见；通过在编码器上滑动分析器来调制通过分析器窗口获得的发光光谱，从而能够在不进行成像的情况下检测到小的位移。我们制备了两种类型的光谱标尺，一种带有荧光编码器，另一种带有 X 射线激发光致发光（XEOL）编码器。荧光标尺使用两种类型的量子点形成分别用 633nm 光激发、发射波长为 645nm 和 680nm 的条纹。每个标尺类型都覆盖有鸡胸组织以模拟植入。XEOL 标尺产生了很强的信号，几乎没有组织自发荧光，但使用电离辐射，而荧光标尺使用非电离的红光激发，但需要进行光谱拟合以考虑组织自发荧光。两种类型的发光光谱标尺（带有 1mm 宽的分析器窗口，并且通过 6mm 厚的组织进行测量）的精度均<2μm，主要受散粒噪声限制。该方法能够实现组织内高精度的微米至毫米级位移测量，在生物力学和机械化学测量（例如，跟踪术后骨愈合和植入物相关感染）中具有应用前景。
