title: Reprint of 'Draw your assay: Fabrication of low-cost paper-based diagnostic and multi-well test zones by drawing on a paper'.
abstract: Interest in low-cost diagnostic devices has recently gained attention, in part due to the rising cost of healthcare and the need to serve populations in resource-limited settings. A major challenge in the development of such devices is the need for hydrophobic barriers to contain polar bio-fluid analytes. Key approaches in lowering the cost in diagnostics have centered on (i) development of low-cost fabrication techniques/processes, (ii) use of affordable materials, or, (iii) minimizing the need for high-tech tools. This communication describes a simple, low-cost, adaptable, and portable method for patterning paper and subsequent use of the patterned paper in diagnostic tests. Our approach generates hydrophobic regions using a ball-point pen filled with a hydrophobizing molecule suspended in a solvent carrier. An empty ball-point pen was filled with a solution of trichloro perfluoroalkyl silane in hexanes (or hexadecane), and the pen used to draw lines on Whatman® chromatography 1 paper. The drawn regions defined the test zones since the trichloro silane reacts with the paper to give a hydrophobic barrier. The formation of the hydrophobic barriers is reaction kinetic and diffusion-limited, ensuring well defined narrow barriers. We performed colorimetric glucose assays and enzyme-linked immuno-sorbent assay (ELISA) using the created test zones. To demonstrate the versatility of this approach, we fabricated multiple devices on a single piece of paper and demonstrated the reproducibility of assays on these devices. The overall cost of devices fabricated by drawing are relatively lower (<US $0.001 per device) than those derived from wax-printing (US$0.05-0.003) or other approaches.
authors.affiliation: Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011, USA.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Oyola-Reynoso
authors.affiliation: Department of Chemistry, University of Massachusetts Boston, Boston, MA 02138, USA.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Heim
authors.affiliation: Department of Chemistry, University of Massachusetts Boston, Boston, MA 02138, USA.
authors.forename: Julian
authors.initials: J
authors.lastname: Halbertsma-Black
authors.affiliation: Department of Mechanical engineering, McGill University, Montreal, Qc, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Zhao
authors.affiliation: Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011, USA.
authors.forename: Ian D
authors.initials: ID
authors.lastname: Tevis
authors.affiliation: Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011, USA.
authors.forename: Simge
authors.initials: S
authors.lastname: Çınar
authors.affiliation: Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011, USA; Department of Chemical and Biological Engineering, Iowa State University, 2114 Sweeney Hall, Ames, IA 50011, USA.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Cademartiri
authors.affiliation: Department of Mechanical engineering, McGill University, Montreal, Qc, Canada.
authors.forename: Xinyu
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Paper, Print Media, and Biomaterials, Grenoble Institute of Technology, 461 Rue de la Papeterie, 38402 Saint-Martin-d'Héres, France.
authors.forename: Jean-Francis
authors.initials: JF
authors.lastname: Bloch
authors.affiliation: Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011, USA; Center for bio-plastics and bio-renewables, Iowa State University, Ames, IA 50011, USA; Micro-electronics Research Center, Iowa State University, Ames, IA 50011, USA. Electronic address: mthuo@iastate.edu.
authors.forename: Martin M
authors.initials: MM
authors.lastname: Thuo
keywords: Low-cost devices; Paper-based devices; Point of care diagnostics; p-ELISA; μ-Pads