A novel polymer-based nitrocellulose platform for implementing a multiplexed microfluidic paperbased enzyme-linked immunosorbent assay

Nitrocellose(NC)membranes,as porous paper-like substrates with high protein-binding capabilties,are very popular in the field of point-of-care immunoassays.However,generating robust hydrophobic structures in NC membranes to fabricate microfluidic paper-based analytical devices(μPADs)remains a great challenge.At present,the main method relies on an expensive wax printer In addition,NC membranes very easy to adhere during the printing process due to electrostatic adsorption.Herein,we developed a facile,fast and low-cost strategy to fabricateμPADs in NC membranes by screen-printing polyurethane acrylate(PUA)as a barrier material for defning flow channels and reaction zones.Moreover,hydrophobic barriers based on UV-curable PUA can resist various surfactant solutions and organic solvents that are generally used in immunoassays and biochemical reactions.To validate the feasibility of this PUA-based NC membrane for immunoassays in point-of-care testing(POCT),we further designed and assembled a rotational paperbased analytical device for implementing a multiplexed enzyme-linked immunosorbent assay(ELISA)in a simple manner.Using the proposed device under the optimal conditions,alpha fetoprotein(AFP)and carcinoembryonic antigen(CEA)could be identified,with limits of detection of 136 pg/mL and 174 pg/mL,respectively,which are below the threshold values of these two cancer biomarkers for clinical diagnosis.We believe that this reliable device provides a promising plaform for the diagnosis of disease based on ELISA or other related bioassays in limited setings or remote regions.