Three‐dimensional ring‐oven washing technique for a paper‐based immunodevice

Abstract

Washing is a standard step for enzyme-linked immunosorbent assays (ELISA) performed on a paper-based chip, in which nonspecific-binding antibodies and antigens should be removed completely from the paper surface. In this study, a novel threedimensional (3D) washing strategy using a heating ring-oven was carried out on a paper-based chip. Compared with a plane washing mode by a ring-oven, this 3D washing strategy obtained a lower background, as gravity played an important role in the washing step. The paper-based chip was placed on a 3D plastic holder and the waste area was connected to a heating ring. Use of a heating waste area meant that the nonspecific-binding protein was continuously carried to the waste area through gravity and capillary action. The angle between the plastic holder and the ring plane was carefully selected. The effect of washing on different parts of the detection area was investigated by upconversion fluorescence and chemiluminescence (CL). This novel 3D washing strategy was performed for carcinoembryonic antigen detection through CL and a lower detection limit of 2 pg ml −1 was obtained. This approach provides an effective washing strategy to remove nonspecific-binding antibody from a paper-based immunodevice. K E Y W O R D Schemiluminescence, ELISA, nonspecific-binding, paper-based chip, three-dimensional washing

Recent Advances and Applications in Paper-Based Devices for Point-of-Care Testing

“…The 3D washing strategy had a lower background than the flat washing mode, because non-specific binding proteins could be continuously transported to the waste zone by gravity and capillarity. A low LOD of 2 pg/mL was obtained for the detection of CEA by CL [ 283 ]. In 2019, a new fabrication method was used to manufacture a μPad.…”