Fabrication of Miniaturized Microfluidic Paper-Based Analytical Devices for Sandwich Enzyme-Linked Immunosorbent Assays using INKJET Printing

Main application of microfluidic paper-based analytical devices (µPADs) is for low-cost and portable assays. In order to reduce the cost, miniaturization seems to be an effective way to save reagents, samples, materials, etc. Present study demonstrates that mini-µPADs based on nitrocellulose membrane with only 2 main channels can perform sandwich enzyme-linked immunosorbent assays (ELISA) for quantitative determination of human chorionic gonadotropin (hCG). Moreover, the width and the length of these devices are only about 4.0 and 33.4 mm, respectively. Inkjet printing technology, having the advantages of simple and material-saving process, was used to create hydrophobic barrier. Colorimetric signals from ELISA captured by digital camera and measured by ImageJ software shows that these µPADs can quantitative determine of hCG in the range from 5 to 10 000 ng/mL. Furthermore, duration for each tests is only about 5 min. The success in fabricating miniaturized µPADs shows the potentials to reduce the size of µPADs as well as the amount of needed samples, time and reagents. For all these reasons, this miniaturization concept can be applied to many further applications of analytical biochemical assays.