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

Background/unmet need

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.

Invention Description

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.

Market potential/applications

Companies developing point-of-care diagnostics 

Development Stage

Lab/bench prototype