3D origami-based multifunction-integrated immunodevice: low-cost and multiplexed sandwich chemiluminescence immunoassay on microfluidic paper-based analytical device.

A novel 3D microfluidic paper-based immunodevice, integrated with blood plasma separation from whole blood samples, automation of rinse steps, and multiplexed CL detections, was developed for the first time based on the principle of origami (denoted as origami-based device). This 3D origami-based device, comprised of one test pad surrounded by four folding tabs, could be patterned and fabricated by wax-printing on paper in bulk. In this work, a sandwich-type chemiluminescence (CL) immunoassay was introduced into this 3D origami-based immunodevice, which could separate the operational procedures into several steps including (i) folding pads above/below and (ii) addition of reagent/buffer under a specific sequence. The CL behavior, blood plasma separation, washing protocol, and incubation time were investigated in this work. The developed 3D origami-based CL immunodevice, combined with a typical luminuol-H(2)O(2) CL system and catalyzed by Ag nanoparticles, showed excellent analytical performance for the simultaneous detection of four tumor markers. The whole blood samples were assayed and the results obtained were in agreement with the reference values from the parallel single-analyte test. This paper-based microfluidic origami CL detection system provides a new strategy for a low-cost, sensitive, simultaneous multiplex immunoassay and point-of-care diagnostics.

A novel chemiluminescence paper microfluidic biosensor based on enzymatic reaction for uric acid determination.

In this work, chemiluminescence (CL) method was combined with microfluidic paper-based analytical device (µPAD) to establish a novel CL µPAD biosensor for the first time. This novel CL µPAD biosensor was based on enzyme reaction which produced H(2)O(2) while decomposing the substrate and the CL reaction between rhodanine derivative and generated H(2)O(2) in acid medium. Microchannels in µPAD were fabricated by cutting method. And the possible CL assay principle of this CL µPAD biosensor was explained. Rhodanine derivative system was used to reach the purpose of high sensitivity and well-defined signal for this CL µPAD biosensor. And the optimum reaction conditions were investigated. The quantitative determination of uric acid could be achieved by this CL µPAD biosensor with accurate and satisfactory result. And this biosensor could provide good reproducible results upon storage at 4°C for at least 10 weeks. The successful integration of µPAD and CL reaction made the final biosensor inexpensive, easy-to-use, low-volume, and portable for uric acid determination, which also greatly reduces the cost and increases the efficiency required for an analysis. We believe this simple, practical CL µPAD biosensor will be of interest for use in areas such as disease diagnosis.