Design, fabrication and characterisation of Si‐based capillary‐driven microfluidic devices. (1st December 2018)

• Record Type: Journal Article
• Authors: Ye, Yifei; Zhao, Yang; Cheng, Jie; Li, Mingxiao; Huang, Chengjun
• Is Part Of: Micro & nano letters. Volume 13:Number 12(2018)
• Page Start: 1682
• Page End: 1687
• Publication Date: 2018-12-01
• Subjects: self‐assembly -- capillarity -- etching -- silicon -- catalysis -- microfluidics -- monolayers -- elemental semiconductors -- copper -- microfabrication -- contact angle -- hydrophilicity -- photolithography; buffer loading -- flow resistor -- micropillar array -- surface modified device -- controllable autonomous capillary flow delivery -- sequential capillary flow generation -- controlled flow rate -- propagation distance -- effective capillary pump -- point‐of‐care testing systems -- lidless silicon‐based capillary‐driven microfluidic device -- deep silicon etch technique -- surface hydrophilisation modification method -- copper‐catalysed azide‐alkyne cycloaddition reaction -- snake‐shaped microchannel -- self‐pumping -- self‐assembly monolayer -- lithographic technique -- contact angle -- aspect ratio -- size 25.0 mum -- size 5.0 mum -- size 120.0 mm -- size 0.05 mm -- depth 0.025 mm -- Si -- Cu; Nanotechnology -- Periodicals; Nanostructures -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1049/mnl.2018.5120
• Languages: English
• ISSNs: 1750-0443

Abstract

Abstract : Capillary‐driven microfluidic devices have a great potential for the point‐of‐care testing systems based on the advantages of self‐pumping, low reagent usage and rapid detection. Here, the study presents a lidless Si‐based capillary‐driven microfluidic device, comprising two inlets for sample and buffer loading, a snake‐shaped microchannel (120/0.05/0.025 mm in length/width/depth) as a flow resistor, a micropillar array (25/5/8 μm in height/diameter/pitch) as a capillary pump and a vent. It was fabricated with lithographic technique in combination with deep Si etch technique. A simple and stable surface hydrophilisation modification method was demonstrated on the device by forming a self‐assembly monolayer through Cu‐catalysed azide‐alkyne cycloaddition reaction. The surface modified device allowed controllable autonomous capillary flow delivery with a contact angle of around 40° stabilised for at least 90 days. The design of two inlets with one common long snake‐shaped microchannel provided the sequential capillary flow generation and propagation with controlled flow rate and propagation distance, while the micropillar array with a high aspect ratio of 5 was considered as an effective capillary pump. Based on the obtained results, the proposed device makes possible for the on‐chip biosensing applications as a part of integrated point‐of‐care testing systems.