Design Of Electromagnet-driven Valve In Microfluidic Chips

Microfluidic chips, also called lab-on-a-chip, enable the miniaturization,integration, automation, and parallelization of biochemical assays in a set of fluidic unitoperations, and allow the easy, fast, and cost-efficient implementation of differentapplication-specific biochemical process.Successful miniaturization and commercialization of fully integrated microfluidicsystems depend on the development of reliable microvalves. Microvalves have beendeveloped in the form of active or passive microvalves employing mechanical,non-mechanical and external systems. Even though great progress has been madeduring the last30years, there is plenty of room for further improving the performanceof existing microvalves.As a maskless fabrication technique, water-assisted femtosecond laser ablationutilizing laser-induced breakdown in water with bubbles, high-speed jet and shockwave provides flexible methods for fabricating2D/3D microstructures in transparentmaterials.In this paper, an electromagnetic actuator with a3D helical configuration fabricatedin the commercially available silica glass substrates has been firstly presented to theauthor’s knowledge. Firstly, single helical or various helical microchannel arrays with40-100μm diameters were designed and manufactured in common isotropic silica glassby water-assisted femtosecond laser ablating technology on a3D stage with a step sizeof100nm. Then superfine graphite powder was selected as conductive material andinfused along the microchannels with a high filling ratio using ultrasonic oscillation.And the glass-based helical electromagnetic actuator was elaborately packaged in orderto be connected to the exterior devices subsequently. Finally, the helical actuator waselectronically and mechanically analyzed by Finite Element Method software ANSYS,tested practically and justified to be an effective tool for manipulating micro-magneticparticles or any suitable micro functional elements.The helical electromagnetic actuator is supposed to be integrated in themicrofluidic chips and possess considerable fluidic functions such as valving, metering,mixing, transportation, and separation.