Tokihiro Jodie C, Robertson Ingrid H, Gregucci Denise, Shin Albert, Michelini Elisa, Nicholson Tristan M, Olanrewaju Ayokunle O, Theberge Ashleigh B, Berthier Jean, Berthier Erwin
Department of Chemistry, University of Washington, Box 351700, Seattle, Washington, 98195, USA.
G. Ciamician Department of Chemistry, University of Bologna, Bologna, Italy.
Sci Rep. 2024 Dec 30;14(1):31732. doi: 10.1038/s41598-024-82329-3.
Trigger valves are fundamental features in capillary-driven microfluidic systems that stop fluid at an abrupt geometric expansion and release fluid when there is flow in an orthogonal channel connected to the valve. The concept was originally demonstrated in closed-channel capillary circuits. We show here that trigger valves can be successfully implemented in open channels. We also show that a series of open-channel trigger valves can be placed alongside or opposite a main channel resulting in a layered capillary flow. We developed a closed form model for the dynamics of the flow at trigger valves based on the concept of average friction length and successfully validated the model against experiments. For the main channel, we discuss layered flow behavior in the light of the Taylor-Aris dispersion theory and in the channel turns by considering Dean theory of mixing. This work has potential applications in autonomous microfluidics systems for biosensing, at-home or point-of-care sample preparation devices, hydrogel patterning for 3D cell culture and organ-on-a-chip models.
触发阀是毛细管驱动微流体系统的基本特征，它在几何形状突然扩张处阻止流体流动，并在与该阀相连的正交通道中有流动时释放流体。这一概念最初是在封闭通道毛细管回路中得到证明的。我们在此表明，触发阀能够成功应用于开放通道。我们还表明，一系列开放通道触发阀可以放置在主通道的旁边或对面，从而产生分层毛细管流。我们基于平均摩擦长度的概念，为触发阀处的流动动力学开发了一个封闭形式的模型，并通过实验成功验证了该模型。对于主通道，我们根据泰勒 - 阿里斯弥散理论讨论分层流动行为，并通过考虑迪恩混合理论讨论通道转弯处的情况。这项工作在用于生物传感的自主微流体系统、家庭或即时护理样品制备装置、用于3D细胞培养和芯片器官模型的水凝胶图案化方面具有潜在应用。
