Functionalization of paper using photobleaching: A fast and convenient method for creating paper‐based assays with colorimetric and fluorescent readout

Abstract

Lateral flow immunoassays (LFIA), where a protein–protein interaction can be monitored on a test strip by a color reaction, are of high interest in the field of point‐of‐care diagnostics due to their cost‐efficient production, portability, and ease of use. Despite their simple appearance, state‐of‐the‐art manufacturing of such test strips is not trivial since the strips comprise of several reaction zones: cellulose serves as hydrophilic support with excellent flow properties; and nitrocellulose is the membrane of choice for zones with immobilized biomolecules due to its hydrophobicity and thus preferable adhesion properties. These individual reaction zone membranes need to be joined together after fabrication. Variations in general membrane properties and production‐related lot‐to‐lot variations make it difficult to produce reliable tests with high reproducibility. In this paper, we present a facile and rapid method to immobilize antibodies directly onto cellulose by using maskless projection lithography. With this method it is possible to manufacture LFIA strips with individual reaction zones in a single material, i.e. cellulose.