Semi-enclosed microfluidic device on glass-fiber membrane with enhanced signal quality for colorimetric analyte detection in whole blood

Microfluidic analytical devices manufactured on paper and similar inexpensive substrates (mu-PADs) have shown considerable promise for disease diagnostics in resource-limited regions. However, current commercialization approaches can be improved substantially by addressing existing technical challenges associated with mu-PADs. Among these, off-device plasma separation from whole blood is a critical challenge in mu-PAD technology that limits commercialization. Existing mu-PADs made by combining multiple components require extra fabrication steps and manufacturing material. Our approach utilizes a two-step plasma process to fabricate single-layer semi-enclosed mu-PADs directly on a commercially available blood plasma separation membrane to incorporate blood plasma separation functionality into the device. The semi-enclosed mu-PADs are bonded with low-cost adhesive plastic tape to provide mechanical support to the device and make it more mechanically robust for field applications. Detection zones of the mu-PADs have also been modified with a cellulose nanocrystal (CNC) to increase colorimetric signal homogeneity, thus enhancing signal quality. The CNC-modified mu-PADs have been used for colorimetric detection of two model analytes (glucose and albumin) in whole blood. Colorimetric signals for both glucose and albumin from whole blood samples were consistent with the calibration curves generated using stock solutions.

Automated summary

Microfluidic analytical devices on paper have great potential for disease diagnostics in resource-limited areas, but current commercialization is hindered by technical challenges. The separation of plasma from whole blood is a key challenge that needs to be addressed.