Title
Paper-based microfluidic devices on fibrous platforms with designed structure
Authors
FLORIN CIOLACU

Received January 12, 2018
Published Volume 52 Issue 9-10 October-December
Keywords paper-based microfluidics, wax printing, capillary flow, micro-channels design

Abstract
Paper-based microfluidic devices are emerging as a new technology for high-tech applications in diagnostics or as potential alternative tools for various analytical tasks. This paper demonstrates a novel concept to control fluid transport inside paper-based microfluidic devices, by using paper sheets with designed structure. Fibrous structures with controlled characteristics have been designed and fabricated to be used as a platform for making paper-based microfluidic devices. A series of paper sheets of 80 g/m2, with different fibrous composition, were fabricated on a lab former in the absence of additives and fillers using two pulps, in different ratios: a softwood bleached chemical pulp and a mercerized pulp (Porosanier J-HP). The mercerized pulp was beaten in a Jokro mill with modified rolls, specially designed for increasing cutting effects. Hydrophobic barriers have been designed inside the paper substrates by the wax printing method. The heating process that follows printing determines wax penetration within paper in both directions, vertically and horizontally, reducing the resolution of printed patterns. The limits of the method are discussed from this point of view. The influence of parameters, such as pulp type, fibrous composition and channel width, on the flow rates through the channel was investigated by monitoring the capillary-driven fluid flow of aqueous solutions.