Microfluidic Paper-Based Analytical Devices (μPADs) and Micro Total Analysis Systems (μTAS): Development, Applications and Future Trends

Abstract

Microfluidic paper-based analytical devices and micro total analysis systems are relatively new group of analytical tools, capable of analyzing complex biochemical samples containing macromolecules, proteins, nucleic acids, toxins, cells or pathogens. Within one analytical run, fluidic manipulations like transportation, sorting, mixing or separation are available. Recently, microfluidic devices are a subject of extensive research, mostly for fast and non-expensive biochemical analysis but also for screening of medical samples and forensic diagnostics. They are used for neurotransmitter detection, cancer diagnosis and treatment, cell and tissue culture growth and amplification, drug discovery and determination, detection and identification of microorganisms. This review summarizes development history, basic fabrication methods, applications and also future development trends for production of such devices.

Keywords: Biochemical analysis; Detection systems; Micro total analysis systems (μTAS); Micro-chip chromatography; Micro-planar chromatography (micro-TLC); Microfluidic paper-based analytical devices (μPADs).

Fig. 1

a General view of a strip of prefabricated screw valves. A single valve has been separated from the strip using a razor blade. b Microfluidic gradient generator containing two embedded solenoid valves, two embedded screw valves and one embedded pneumatic valve (by Hulme et al. 2009 [58]; reproduced by permission of the Royal Society of Chemistry)

Fig. 2

Microheater incorporated in polymer-based (PDMS) microfluidic systems (by Siegel et al. 2007 [66])

Fig. 3

Typical scheme of flow-focusing microfluidic device. An orifice is placed at a distance Hf = 250 μm downstream of three coaxial inlet streams. Water is supplied to the two side channels which have widths Wo = 120 μm; monomer is forced into the central channel which has a width Wi = 100 μm. The width of the orifice is D = 80 μm; the width of the downstream channel is W = 240 μm (Nie et al. 2008 [68]; with kind permission from Springer Science + Business Media)

Fig. 4

Fabrication of paper-based microfluidic device using photolithography technique (described by Martinez et al. 2007 [42])

Fig. 5

Paper cutting technique for fabrication of paper-based microfluidic device (reprinted with permission from Fenton et al. 2009 [75]; copyright (2012) American Chemical Society)

Fig. 6

Schematic illustration of the processes to produce patterned paper with wax (described by Lu et al. [78])

Fig. 7

Three-dimensional paper microfluidic devices assembled using the principles of origami (reprinted with permission from Liu and Crooks, 2011 [87]; copyright (2012) American Chemical Society)

Fig. 8

General strategy for performing inexpensive bioassays in remote locations and for exchanging the results of the tests with offsite technicians (reprinted with permission from Martinez et al. 2008 [70]; copyright (2012) American Chemical Society)