Over the past two decades, researchers have advanced and employed integrated microfluidic circuitry to enable a wide range of chemical and biological ‘lab-on-a-chip’ capabilities. Yet in recent years, a wholly different field, soft robotics, has begun harnessing microfluidic circuitry as a promising means to enhance soft robot autonomy. Unfortunately, key challenges associated with not only the fabrication of microfluidic circuitry, but also its integration with soft robotic systems represent critical barriers to progress. To overcome such issues, here we present a strategy that leverages ‘in situ direct laser writing (isDLW)’—a submicron-scale additive manufacturing (or ‘three-dimensional (3D) printing’) approach developed previously by our group—to fabricate microfluidic circuit elements and soft microrobotic actuators directly inside of enclosed microchannels. In addition, we introduce ‘normally closed’ microfluidic transistors that comprise free-floating sealing discs designed to block source-to-drain fluid flow until the application of a target gate pressure. As an exemplar, we printed microfluidic transistors with distinct gate activation properties as well as identical soft microgrippers downstream of each drain within 40 m-tall microchannels. Experimental results for a source pressure of 100 kPa revealed that microgripper deformation was prevented in the absence of a gate input; however, increasing the gate pressure to 300 kPa induced actuation of one set of microgrippers, while a further increase to 400 kPa led to both sets of microgrippers actuating successfully. These results suggest that the presented isDLW-based strategy for manufacturing and integrating 3D microfluidic circuit elements and microrobotic end effectors could offer unique potential for emerging soft robotic applications.

在过去的二十年里，研究人员已经改进并采用了集成微流体电路，以实现广泛的化学和生物“芯片实验室”功能。然而近年来，一个完全不同的领域，软机器人，已经开始利用微流体电路作为增强软机器人自主性的有前途的手段。不幸的是，关键挑战不仅与微流体电路的制造有关，而且与软机器人系统的集成有关，这也是进步的关键障碍。为了克服这些问题，我们在这里提出了一种利用 '原位直接激光写入（是DLW)”——我们小组之前开发的一种亚微米级增材制造（或“三维（3D）打印”）方法——直接在封闭的微通道内制造微流体电路元件和软微机器人执行器。此外，我们引入了“常闭”微流体晶体管，其中包括自由浮动密封盘，旨在阻止源到排水的流体流动，直到应用目标门压力。作为一个例子，我们印刷了具有不同栅极激活特性的微流体晶体管以及每个漏极下游 40米高的微通道。源压力为 100 kPa 的实验结果表明，在没有门输入的情况下防止了微夹具变形；然而，将浇口压力增加到 300 kPa 会导致一组微型夹具的致动，而进一步增加到 400 kPa 会导致两组微型夹具都成功致动。这些结果表明，所提出的是制造和集成的3D微流电路元件和微型机器人的末端执行器可以为新兴的软机器人应用提供独特的基于潜在DLW策略。