Chung Kwanghun, Cho Jae Kyu, Park Edward S, Breedveld Victor, Lu Hang
School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Anal Chem. 2009 Feb 1;81(3):991-9. doi: 10.1021/ac802031j.
We report an in situ method for three-dimensionally resolved temperature measurement in microsystems. The temperature of the surrounding fluid is correlated from Brownian diffusion of suspended nanoparticles. We use video-microscopy in combination with image analysis software to selectively track nanoparticles in the focal plane. This method is superior with regards to reproducibility and reduced systematic errors since measuring Brownian diffusivity does not rely on fluorescence intensity or lifetime of fluorophores. The efficacy of the method is demonstrated by measuring spatial temperature profiles in various microfluidic devices that generate temperature gradients and by comparing these results with numerical simulations. We show that the method is accurate and can be used to extract spatial temperature variations in three dimensions. Compared to conventional methods that require expensive multiphoton optical sectioning setups, this technique is simple and inexpensive. In addition, we demonstrate the capability of this method as an in situ tool for simultaneously observing live cells under the microscope and monitoring the local temperature of the cell medium without biochemical interference, which is crucial for quantitative studies of cells in microfluidic devices.
我们报告了一种用于微系统中三维分辨温度测量的原位方法。通过悬浮纳米颗粒的布朗扩散来关联周围流体的温度。我们将视频显微镜与图像分析软件相结合，以选择性地跟踪焦平面中的纳米颗粒。由于测量布朗扩散率不依赖于荧光团的荧光强度或寿命，因此该方法在重现性和减少系统误差方面具有优势。通过测量在各种产生温度梯度的微流体装置中的空间温度分布，并将这些结果与数值模拟进行比较，证明了该方法的有效性。我们表明该方法是准确的，可用于提取三维空间温度变化。与需要昂贵的多光子光学切片装置的传统方法相比，该技术简单且成本低廉。此外，我们展示了该方法作为一种原位工具的能力，可在显微镜下同时观察活细胞并监测细胞培养基的局部温度，而不会产生生化干扰，这对于微流体装置中细胞的定量研究至关重要。
