Microfluidic Devices Explained
The premise of microfluidics is the use of micrometer-sized channels for the manipulation and analysis of fluids.1 There are many techniques for the fabrication of microfluidic devices, all with the purpose of directing fluid into a test zone containing assay reagents. Paper is an attractive material for device fabrication due to its extremely low cost as well as its mechanical properties.2 Paper is created from a suspension of cellulose fibres in water which is then drained, pressed, and dried.2 This yields a randomly interwoven network of fibres which transport liquids via capillary action, eliminating the need for an external force (eg. a pump3). The structure also allows for the storage of reagents through absorbance, filtration of the sample, and a large surface area for maximization of immobilized reagents and minimization of reaction time.2 Additionally, paper is chemically and biologically inert, and biodegradable.2 The various types of paper-based devices are often collectively referred to as microfluidic paper-based analytical devices (μPADs)3, “lab-on-paper”4 , or “lab-on-a-chip”1 .
The premise of microfluidics is the use of micrometer-sized channels for the manipulation and analysis of fluids.1 There are many techniques for the fabrication of microfluidic devices, all with the purpose of directing fluid into a test zone containing assay reagents. Paper is an attractive material for device fabrication due to its extremely low cost as well as its mechanical properties.2 Paper is created from a suspension of cellulose fibres in water which is then drained, pressed, and dried.2 This yields a randomly interwoven network of fibres which transport liquids via capillary action, eliminating the need for an external force (eg. a pump3). The structure also allows for the storage of reagents through absorbance, filtration of the sample, and a large surface area for maximization of immobilized reagents and minimization of reaction time.2 Additionally, paper is chemically and biologically inert
1. Fiorini, G. S.; Chiu, D. T. Disposable microfluidic devices: fabrication, function, and application . BioTechniques 2005, 38, 429-446.2. Akyazi, T.; Basabe-Desmonts, L.; Benito-Lopez, F. Review on microfluidic paper-based analytical devices towards commercialisation . Analytica Chimica Acta 2018, 1001, 1-17.3. Koesdjojo, M. T.; Pengpumkiat, S.; Wu, Y.; Boonloed, A.; Huynh, D.; Remcho, T. P.; Remcho, V. T. Cost Effective Paper-Based Colorimetric Microfluidic Devicesand Mobile Phone Camera Readers for the Classroom . J. Chem. Educ. 2015, 92, 737-741.4. Li, X.; Ballerini, D. R.; Shen, W. A perspective on paper-based microfluidics: Current status and future trends . Biomicrofluidics 2012, 6, 011301-13.