Patients with UVFI suffer from dysphagia and report significant improvement in swallowing symptoms following VFM. The symptomatic improvement appears to be durable over time.

Microfluidic paper-based analytical devices (microPADs) are emerging as cost-effective and portable platforms for point-of-care assays. A fundamental limitation of microPAD fabrication is the imprecise nature of most methods for patterning paper. The present work demonstrates that paper patterned via wax printing can be miniaturized by treating it with periodate to produce higher-resolution, high-fidelity microPADs. The optimal miniaturization parameters were determined by immersing microPADs in various concentrations of aqueous sodium periodate (NaIO4) for varying lengths of time. This treatment miniaturized microPADs by up to 80% in surface area, depending on the concentration of periodate and length of the reaction time. By immersing microPADs in 0.5-M NaIO4 for 48 hours, devices were miniaturized by 78% in surface area, and this treatment allowed for the fabrication of functional channels with widths as small as 301 µm and hydrophobic barriers with widths as small as 387 µm. The miniaturized devices were shown to be compatible with redox-based colorimetric assays and enzymatic reactions. This miniaturization technique provides a new option for fabricating sub-millimeter-sized features in paper-based fluidic devices without requiring specialized equipment and could enable new capabilities and applications for microPADs.

No abstract

Microfluidic paper-based analytical devices (microPADs) have emerged as a promising platform for point-of-care diagnostic devices. While the inherent wicking properties of microPADs allow for fluid flow without supporting equipment, this also presents a major challenge in achieving robust fluid control, which becomes especially important when performing complex multi-step assays. Herein, we describe an ideal method of fluid control mediated by wax-printed fluidic time delays. This method relies on a simple fabrication technique, does not utilize chemicals/reagents that could affect downstream assays, is readily scalable, and has a wide temporal range of tunable fluid control. The delays are wax printed on both the top and bottom of pre-fabricated microPAD channels, without subsequent heating, to create hemi-/fully-enclosed channels. With these wax printed delays, we were able to tune the time it took aqueous solutions to wick across a 25 mm-long channel between 3.6 min and 13.4 min. We then employed these fluid delays in the sequential delivery of four dyes to a test zone. Additionally, we demonstrated the automation of two simple enzymatic assays with this fluid control modality. This method of fluid control may allow future researchers to automate more complex assays, thereby further advancing microPADs toward real-world applications.

3b. Laryngoscope, 127:1832-1837, 2017.