A composite lateral flow test substrate by capillary deposition of cellulose on synthetic paper

Lateral flow test (LFT) has been a very popular platform for point-of-care testing (POCT). Traditionally, LFT uses (nitro)cellulose or microstructured polymer as the substrate. In this work, we develop a new LFT substrate by capillary deposition of cellulose on a microstructured polymer substrate off-stoichiometry thiol-ene (OSTE) synthetic paper, which is formed by interlocked slanted OSTE micropillars. This substrate has uniform thickness and stable lateral flow rate with customized design. The lateral flow rate can be adjusted by changing the dimensions of the LFT test strip, the concentration of deposited cellulose, or the Tween 20 concentration in cellulose to meet specific requirements. Spotting tests are conducted on this substrate to facilitate the following immobilization of immuno reagents. We successfully use this substrate in various applications including urine glucose detection (an enzyme-based immunoassay), iodate detection of saline solutions, and plasma separation from whole blood, which proves this substrate has enormous potential for LFT in POCT.