Hollow-Channel Microfluidic Paper-Based Analytical Devices
Life Sciences : Diagnostics
Available for licensing
- Richard Crooks, Ph.D. , Chemistry and Biochemistry
- Christophe Renault , University of Texas at Austin
- Stephen Fosdick , University of Texas at Austin
- Xiang Li , University of Texas at Austin
The fabrication of point-of-care diagnostics on patterned paper instead of glass or plastic is expected to reduce the cost of the sensors. Most paper-based devices rely on capillary action to move the sample across the device. This strategy obviates the need for an external pump, producing cost savings and simplicity.
However, capillary-driven flow is relatively slow and limits the size of the paper device. UT Austin researchers propose a technique to fabricate hollow channels in paper-based point-of-care devices. By removing the cellulose fibers from within the channel, we can use fast, pressure-driven flow and hence shorten the liquid transport time in the paper device.
The invention consists of a specific method to fabricate hollow channels in a microfluidic paper-based device. The resulting hollow channels enable flow at low pressure (less than 0.5 mbar). The purpose of this invention is to fabricate point-of-care sensors where the mass of a simple droplet of sample (few tens of microliters) is able to induce pressure-driven flow within the device.
- Hollow channels allow flow of more viscous solutions and sensing of micrometer-sized objects, such as bacteria or microbeads.
- Unlike existing solutions that require high pressure flow in hollow channels, the proposed design only requires the pressure of a single drop of liquid (˜0.2 mbar) to induce fast pressure-driven flow.
- Seven times faster flow rate than capillary-driven flow
- High flow rate reduces analysis time and also makes it possible to use larger fluidic networks.
- The microfluidic channels in the paper-based device are mainly free of cellulose fibers which could cause non-specific absorption.
- No external equipment, such as a syringe pump, is required to force the liquid into the channel, which means that this type of hollow channel should be suitable for point-of-care.
- At least one wall of the channel is made hydrophilic.
- The device is fabricated in a single wax-patterning strip.
- The flow can be controlled from 0 to several mm/s by leaving paper barriers or wax weirs along the hollow channel.
- Electrodes can be integrated in the hollow channel to perform useful and reproducible electrochemistry.
Companies developing point-of-care diagnostics