Microfluidic Paper-Based Analytical Devices: From Design to Applications

Abstract

Microfluidic paper-based analytical devices (μPADs) have garnered significant interest as a promising analytical platform in the past decade. Compared with traditional microfluidics, μPADs present unique advantages, such as easy fabrication using established patterning methods, economical cost, ability to drive and manipulate flow without equipment, and capability of storing reagents for various applications. This Review aims to provide a comprehensive review of the field, highlighting fabrication methods available to date with their respective advantages and drawbacks, device designs and modifications to accommodate different assay needs, detection strategies, and the growing applications of μPADs. Finally, we discuss how the field needs to continue moving forward to realize its full potential.

Paper-based immunoassay based on 96-well wax-printed paper plate combined with magnetic beads and colorimetric smartphone-assisted measure for reliable detection of SARS-CoV-2 in saliva

“…In the era of sustainability, the use of paper-based devices and smartphone-assisted biosensors has established one of the main pillars in the diagnostics field. The use of paper in their design allows for: i) the fabrication of the plastic-free devices; ii) the loading of the reagents onto the cellulose network delivering a reagent-free measure; iii) the customization of microfluidics with an equipment-free system exploiting the capillarity of the paper; iv) a treatment-free measurement thanks to the filter paper which can treat the sample during the analysis, v) the possibility to be incinerated, rendering more sustainable the management of waste in the case of infected samples ( Cate et al, 2015 ; Hamedi et al, 2016 ; Caratelli et al, 2020 ; Grant et al, 2020; Antiochia, 2021 , Zhu et al, 2021 , Zhang et al, 2020 , Noviana et al, 2021 ). At the same level, smartphone-assisted devices can boost the acquisition of the signal by smartphone, avoiding the use of a dedicated instrument.…”

Fabrication of Paper-Based Microfluidics by Spray on Printed Paper

“…Moreover, paper is biodegradable, biocompatible, and flammable for easy disposal by incineration and good for colorimetric tests [ 13 ]. The use of a paper device was first demonstrated by Müller and Clegg dating back to 1949 [ 14 ], however, it was not until 2007 that paper-based microfluidics regained attention, thanks to the work conducted by Whitesides’s group.…”

“…As for fabrication of paper-based microfluidics, this can be divided into two groups, that is, patterning the hydrophobic barrier and shaping [ 14 ]. For the former, it can be further organized into four categories: plotting, printing, masking, and stamping [ 24 ].…”

“…For the former, it can be further organized into four categories: plotting, printing, masking, and stamping [ 24 ]. As to the latter, cutting, embossing, and laser etching are included [ 14 ]. The pros and cons for each method are summarized in the literature [ 14 ].…”

“…As to the latter, cutting, embossing, and laser etching are included [ 14 ]. The pros and cons for each method are summarized in the literature [ 14 ]. For example, the photolithographic technique was first adopted by Whitesides’s group and the channel wall, which is the solid, hydrophobic barrier, is the cured photoresist.…”