Automatic sequential fluid handling with multilayer microfluidic sample isolated pumping

Abstract

To sequentially handle fluids is of great significance in quantitative biology, analytical chemistry, and bioassays. However, the technological options are limited when building such microfluidic sequential processing systems, and one of the encountered challenges is the need for reliable, efficient, and mass-production available microfluidic pumping methods. Herein, we present a bubble-free and pumping-control unified liquid handling method that is compatible with large-scale manufacture, termed multilayer microfluidic sample isolated pumping (mlSIP). The core part of the mlSIP is the selective permeable membrane that isolates the fluidic layer from the pneumatic layer. The air diffusion from the fluidic channel network into the degassing pneumatic channel network leads to fluidic channel pressure variation, which further results in consistent bubble-free liquid pumping into the channels and the dead-end chambers. We characterize the mlSIP by comparing the fluidic actuation processes with different parameters and a flow rate range of 0.013 ll/s to 0.097 ll/s is observed in the experiments. As the proof of concept, we demonstrate an automatic sequential fluid handling system aiming at digital assays and immunoassays, which further proves the unified pumping-control and suggests that the mlSIP is suitable for functional microfluidic assays with minimal operations. We believe that the mlSIP technology and demonstrated automatic sequential fluid handling system would enrich the microfluidic toolbox and benefit further inventions. V C 2015 AIP Publishing LLC.

Fabrication of a Three-Layer PDMS Pneumatic Microfluidic Chip for Micro Liquid Sample Operation

“…11 Compared with the two-layer microfluidic chips, multilayer (more than three layers) microfluidic chips have shown the advantage of achieving better performances in reducing chip size and have become a hot topic in microfluidic fields. 12,13 However, the multilayer microfluidic chips reported were always fabricated by complicated, costly, and time-consuming processes, and the reliability and portability of these devices were always not good. 14 For the three-layer PDMS pneumatic microfluidic chips, their control systems and pressure generation were usually off chips.…”