Many microfluidic processes rely heavily on precise temperature control. Though internally-contained heaters have been developed using traditional fabrication methods, they are limited in their ability to isothermally heat a precisely defined volume. Advances in 3D printing have led to high resolution printers capable of using bio-compatible materials and achieving geometry resolutions near 20 μm. 3D printing's ability to create arbitrary 3D structures with an arbitrary 3D orientation as opposed to traditional microfluidic fabrication methods enables new three-dimensional heater geometries to be created. As examples, we demonstrate three new 3D heater geometries: a non-planar serpentine channel, a tapered helical channel, and a diamond channel. These new geometries are shown through finite element simulation to isothermally heat microfluidic channels of cross section 200 μm × 200 μm with a 0.1 °C temperature difference along up to 91% of a 10 mm length, compared to designs from the literature that are only able to have that same temperature distance over several μms. Finally, a set of design rules to create isothermal regions in 3D based on the desired temperature, heater pitch, heater gradient, and radial space around a target volume are detailed.

中文翻译：

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3D 打印在微流体设备中实现均匀的温度分布

许多微流体过程严重依赖于精确的温度控制。尽管已经使用传统的制造方法开发了内部加热器，但它们在等温加热精确定义的体积的能力方面受到限制。3D 打印的进步导致高分辨率打印机能够使用生物兼容材料并实现接近 20 μm 的几何分辨率。与传统的微流体制造方法不同，3D 打印能够创建具有任意 3D 方向的任意 3D 结构，从而能够创建新的三维加热器几何形状。作为示例，我们展示了三种新的 3D 加热器几何形状：非平面蛇形通道、锥形螺旋通道和金刚石通道。这些新的几何形状通过有限元模拟显示，以等温加热横截面为 200 μm × 200 μm 的微流体通道，在 10 mm 长度的 91% 处温差为 0.1 °C，与文献中的设计相比，这些设计只能在几个 μms 内具有相同的温度距离。最后，详细介绍了一组设计规则，用于根据所需温度、加热器间距、加热器梯度和目标体积周围的径向空间在 3D 中创建等温区域。