A review on wax printed microfluidic paper-based devices for international health

Abstract

Paper-based microfluidics has attracted attention for the last ten years due to its advantages such as low sample volume requirement, ease of use, portability, high sensitivity, and no necessity to well-equipped laboratory equipment and well-trained manpower. These characteristics have made paper platforms a promising alternative for a variety of applications such as clinical diagnosis and quantitative analysis of chemical and biological substances. Among the wide range of fabrication methods for microfluidic paper-based analytical devices (μPADs), the wax printing method is suitable for high throughput production and requires only a commercial printer and a heating source to fabricate complex two or three-dimensional structures for multipurpose systems. μPADs can be used by anyone for in situ diagnosis and analysis; therefore, wax printed μPADs are promising especially in resource limited environments where people cannot get sensitive and fast diagnosis of their serious health problems and where food, water, and related products are not able to be screened for toxic elements. This review paper is focused on the applications of paper-based microfluidic devices fabricated by the wax printing technique and used for international health. Besides presenting the current limitations and advantages, the future directions of this technology including the commercial aspects are discussed. As a conclusion, the wax printing technology continues to overcome the current limitations and to be one of the promising fabrication techniques. In the near future, with the increase of the current interest of the industrial companies on the paper-based technology, the wax-printed paper-based platforms are expected to take place especially in the healthcare industry.

FIG. 1.

(a) Common qualitative test strip for immunoassay. Reprinted with permission from Liu et al., Electroanalysis 26, 1214 (2014). Copyright 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. (b) Common semi quantitative dipstick test for pH determination and colorimetric readout. Reprinted with permission from Morbioli et al., Anal. Chim. Acta 970, 1 (2017). Copyright 2017 Elsevier B.V. (c) Representation of LFA device. Reprinted with permission from Yetisen et al., Lab Chip 13, 2210 (2013). Copyright 2013 The Royal Society of Chemistry.

FIG. 2.

(a) A μPAD prepared for the detection of glucose, protein, and cholesterol. Reprinted with permission from Carrilho et al., Anal. Chem. 81, 7091 (2009). Copyright 2009 American Chemical Society. (b) Wax patterned μPAD after heating. Reprinted with permission from Lu et al., Electrophoresis 30, 1497–1500 (2009). Copyright 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim (c) Chambers at different width of wax printed barriers. Reprinted with permission from Carrilho et al., Anal. Chem. 81, 7091 (2009). Copyright 2009 American Chemical Society.

FIG. 3.

(a) Experimental and computational fluid transport on paper strips. Reprinted with permission from Fu et al., Microfluid. Nanofluid. 10, 29–35 (2011). Copyright 2010 Springer-Verlag. (b) Computational simulation of fluid flow on a fan-shaped nitrocellulose strip. Reprinted with permission from Mendez et al., Langmuir 26, 1380–1385 (2010). Copyright 2010 American Chemical Society.

FIG. 4.

(a) Presentation of multilayers of a 3D μPAD. Reprinted with permission from Carrilho et al., Anal. Chem. 81, 7091 (2009). Copyright 2009 American Chemical Society. (b) Presentation of a 3D μPAD with an extra paper level containing different concentrations of wax. Reprinted with permission from Noh and Phillips, Anal. Chem. 82, 4181–4187 (2010). Copyright 2010 American Chemical Society. (c) Vertical cross section of a wax-printed channel. Reprinted with permission from Renault et al., Langmuir 30, 7030–7036 (2014). Copyright 2014 American Chemical Society. (d) A 4 × 4 zone plate for cell growth. Reprinted with permission from Schonhorn et al., Lab Chip 14, 4653–4658 (2014). Copyright 2014 The Royal Society of Chemistry. (e) Layers of a 3D μPAD for E. coli and phage M13 growth. Reprinted with permission from Tao et al., BioChip J. 9, 97–104 (2015). Copyright 2015 The Korean BioChip Society and Springer.

FIG. 5.

(a) μPAD for the detection of chemical explosives. Reprinted with permission from Peters et al., Anal. Methods 7, 63–70 (2015). Copyright 2015 The Royal Society of Chemistry. (b) A blood typing device fabricated by wax-printing. Reprinted with permission from Noiphung et al., Biosens. Bioelectron. 67, 485–489 (2015). Copyright 2015 Elsevier B.V. (c) A device with 5 zones for AST and ALT testing. Reprinted with permission from Pollock et al., Sci. Transl. Med. 4, 152ra129 (2012). Copyright 2012 American Association for the Advancement of Science.

FIG. 6.

(a) PWE modified μPAD fabricated by wax printing for tumor biomarker detection. Reprinted with permission from Li et al., Electrochim. Acta 120, 102–109 (2014). Copyright 2014 Elsevier Ltd. (b) Electrochemical 3D μPAD consisting of two wax printed layers modified with electrodes for detection of tumor biomarker. Reprinted with permission from Li et al., Sens. Actuators, B 202, 314–322 (2014). Copyright 2014 Elsevier B.V. (c) Two wax printed layers of a μPAD modified with electrodes. Reprinted with permission from Ge et al., Biomaterials 33, 1024–1031 (2012). Copyright 2011 Elsevier Ltd.