title: Novel concept of washing for microfluidic paper-based analytical devices based on capillary force of paper substrates.
abstract: A novel washing technique for microfluidic paper-based analytical devices (μPADs) that is based on the spontaneous capillary action of paper and eliminates unbound antigen and antibody in a sandwich immunoassay is reported. Liquids can flow through a porous medium (such as paper) in the absence of external pressure as a result of capillary action. Uniform results were achieved when washing a paper substrate in a PDMS holder which was integrated with a cartridge absorber acting as a porous medium. Our study demonstrated that applying this washing technique would allow μPADs to become the least expensive microfluidic device platform with high reproducibility and sensitivity. In a model μPAD assay that utilized this novel washing technique, C-reactive protein (CRP) was detected with a limit of detection (LOD) of 5 μg mL-1. Graphical Abstract A novel washing technique for microfluidic paper-based analytical devices (μPADs) that is based on the spontaneous capillary action of paper and eliminates unbound antigen and antibody in a sandwich immunoassay is reported.
authors.affiliation: Graduate School of Chemical Sciences and Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo, 060-8628, Japan.
authors.forename: Saeed
authors.initials: S
authors.lastname: Mohammadi
authors.affiliation: Graduate School of Chemical Sciences and Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo, 060-8628, Japan.|Physical Sciences Department, College of Art and Sciences, Nueva Vizcaya State University, Bayombong, Nueva Vizcaya, 3700, Philippines.
authors.forename: Lori Shayne Alamo
authors.initials: LS
authors.lastname: Busa
authors.affiliation: Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo, 060-8628, Japan.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Maeki
authors.affiliation: Department of Pharmaceutical Science, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, M5S 3M2, Canada.
authors.forename: Reza M
authors.initials: RM
authors.lastname: Mohamadi
authors.affiliation: Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo, 060-8628, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Ishida
authors.affiliation: Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo, 060-8628, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Tani
authors.affiliation: Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo, 060-8628, Japan. tokeshi@eng.hokudai.ac.jp.|ImPACT Research Centre for Advanced Nanobiodevices, Nagoya University, Furo-cho Chikusa-ku, Nagoya, 464-8603, Japan. tokeshi@eng.hokudai.ac.jp.|Innovative Research Centre for Preventive Medical Engineering, Nagoya University, Furo-cho Chikusa-ku, Nagoya, 464-8603, Japan. tokeshi@eng.hokudai.ac.jp.|Institute of Innovation for Future Society, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan. tokeshi@eng.hokudai.ac.jp.
authors.forename: Manabu
authors.initials: M
authors.lastname: Tokeshi
mesh_terms: D000327:Adsorption; D000906:Antibodies / Q000737:chemistry; D000936:Antigen-Antibody Complex / Q000737:chemistry; D000941:Antigens / Q000737:chemistry; D002097:C-Reactive Protein / Q000032:analysis*; D002197:Capillary Action; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods; D056656:Lab-On-A-Chip Devices; D057230:Limit of Detection; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D010209:Paper
chemical_list: D000906:Antibodies; D000936:Antigen-Antibody Complex; D000941:Antigens; D002097:C-Reactive Protein
keywords: C-reactive protein; Capillary force; Immunoassay; Microfluidic paper-based analytical devices