Diffusion-free valve for preprogrammed immunoassay with capillary microfluidics

作     者：Pooya Azizian Jasmina Casals-Terré Jordi Ricart Joan M.Cabot 

作者机构：Energy and Engineering DepartmentLeitat Technological CenterTerrassaBarcelonaSpain Mechanical Engineering DepartmentTechnical University of CataloniaTerrassaBarcelonaSpain 

出 版 物：《Microsystems & Nanoengineering》 (微系统与纳米工程（英文）)

年 卷 期：2023年第9卷第4期

页      面：197-209页

核心收录：

学科分类：0710[理学-生物学] 07[理学] 070205[理学-凝聚态物理] 08[工学] 080501[工学-材料物理与化学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0703[理学-化学] 0811[工学-控制科学与工程] 0702[理学-物理学] 

基　　金：This project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement no.813863 This project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No 801342(Tecniospring INDUSTRY) All authors are joint inventors on a Patent Application PCT/ES2021/070720,which covers theπ-valve concept(international publication number WO 2023/057659 A1) 

主　　题：capillary steps eliminate 

摘      要：By manipulating the geometry and surface chemistry of microfluidic channels,capillary-driven microfluidics can move and stop fluids spontaneously without external ***,complex microfluidic circuits can be preprogrammed by synchronizing the capillary pressures and encoding the surface tensions of microfluidic chips.A key component of these systems is the capillary ***,the main concern for these valves is the presence of unwanted diffusion during the valve loading and activation steps that can cause *** this study,we design and validate a novel diffusion-free capillary valve:theπ-*** valve consists of a 3D structure and a void *** void acts as a spacer between two fluids to avoid direct *** the valve is triggered,the air trapped within the void is displaced by pneumatic suction induced from the capillary flow downstream without introducing a gas bubble into the *** proposed design eliminates diffusive mixing before valve *** simulation is used to study the function and optimize the dimensions of theπ-valve,and 3D printing is used to fabricate either the mould or the microfluidic chip.A comparison with a conventional valve(based on a constrictionexpansion valve)demonstrates that theπ-valve eliminates possible backflow into the valve and reduces the mixing and diffusion during the loading and trigger *** a proof-of-concept,this valve is successfully implemented in a capillary-driven circuit for the determination of benzodiazepine,achieving the successive release of 3 solutions in a 3Dprinted microfluidic chip without external *** results show a 40%increase in the fluorescence intensity using theπ-valve relative to the conventional ***,theπ-valve prevents cross-contamination,minimizes sample use,and facilitates a sophisticated preprogrammed release of fluids,offering a promising tool for conducting automated immunoassays applicable at point-of-