Rapid, Simple and Inexpensive Fabrication of Paper-based Analytical Devices by Parafilm® Hot Pressing

Abstract

Paper-based analytical devices have been substantially developed in recent decades. Many fabrication techniques for paper-based analytical devices have been demonstrated and reported. Herein we report a relatively rapid, simple, and inexpensive method for fabricating paper-based analytical devices using parafilm hot pressing. We studied and optimized the effect of the key fabrication parameters, namely pressure, temperature, and pressing time. We discerned the optimal conditions, including pressure of 3.8 MPa (3 tons), temperature of 80oC, and 3 minutes of pressing time, with the smallest hydrophobic barrier size (821 µm) being governed by laminate mask and parafilm dispersal from pressure and heat. Physical and biochemical properties were evaluated to substantiate the paper functionality for analytical devices. Wicking speed in the fabricated paper strips was slightly slower than that of non-processed paper, resulting from reducing paper pore size. A colorimetric immunological assay was performed to demonstrate the protein binding capacity of the paper-based device after exposure to pressure and heat from the fabrication. Moreover, mixing in two-dimensional paper-based device and flowing in a three-dimensional counterpart were thoroughly investigated, demonstrating that the paper device from this fabrication process is potentially applicable as analytical devices for biomolecule detection. Fast, easy, and inexpensive parafilm hot press fabrication presents an opportunity for researchers to develop paper-based analytical devices in resource-limited environments.

Rapid and inexpensive process to fabricate paper based microfluidic devices using a cut and heat plastic lamination process

“…38,42,44 Techniques to cut paper sheets into stand-alone devices, corresponding to (ii) described above, include using handheld and automated tools such as craft cutters or scissors, and computer controlled knives and lasers. [45][46][47][48][49][50][51][52] Some researchers have used cover tape/lamination tape to enclose open channels and hold individually cut devices to provide support and improve handling and functionality. [49][50][51][52][53] One of the ways that this is accomplished is by creating a hollowed mold of the same shape as the device in a lamination sheet or in Parafilm infused hardened paper, and inserting the paper device in the matched hollow receptacle.…”

“…[45][46][47][48][49][50][51][52] Some researchers have used cover tape/lamination tape to enclose open channels and hold individually cut devices to provide support and improve handling and functionality. [49][50][51][52][53] One of the ways that this is accomplished is by creating a hollowed mold of the same shape as the device in a lamination sheet or in Parafilm infused hardened paper, and inserting the paper device in the matched hollow receptacle. 50 Another is to use pieces of cover tape that have holes for ports for fluid access to the paper device.…”

“…Previously also, lamination sheets have been used for microPAD fabrication as holders or support for individually cut paper devices or for encapsulation, but not for device fabrication or being an integral part of the hydrophobic barriers. 49,50,[53][54][55] The current fabrication process presents many key distinct advantages as compared to commonly used fabrication techniques discussed above. It is a two-step process, involving cutting of microfluidic patterns in the lamination sheets and heating them with a paper sheet in between them for the fabrication of microPADs, which thus are named as "cut and heat microPADs" (CH-microPADs).…”