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Fabrication of Three-dimensional Paper-based Microfluidic Devices for Immunoassays
Published on: March 9, 2017
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A paper-based microfluidic platform with shape-memory-polymer-actuated fluid valves for automated multi-step
Hao Fu1,2, Pengfei Song1,2,3, Qiyang Wu1,2
11Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON M5S 3G8 Canada.
Microsystems & Nanoengineering
|October 23, 2019
Summary
Automated immunoassays are now possible on paper microfluidic devices using shape-memory polymer valves. This integrated platform enables multi-step enzyme-linked immunosorbent assays (ELISAs) with reliable fluid control and smartphone data transmission.
Area of Science:
- Biomedical Engineering
- Analytical Chemistry
- Materials Science
Background:
- Automated, multi-step immunoassays are crucial for point-of-care diagnostics.
- Paper-based microfluidic devices offer a low-cost, portable platform for assays.
- Existing platforms often lack sophisticated fluid control for complex protocols.
Purpose of the Study:
- To develop an integrated paper-based microfluidic platform with shape-memory polymer (SMP)-actuated valves for automated enzyme-linked immunosorbent assays (ELISAs).
- To enable automated, multi-step immunoassays on a single microfluidic paper-based analytical device (μPAD).
- To integrate a portable reader for device control, data acquisition, and wireless transmission for telemedicine applications.
Main Methods:
- Fabrication of a single-layer μPAD storing reagents for sequential delivery.
- Utilized shape-memory polymer (SMP) sheets attached to paper cantilever beams to actuate hydrophilic paper bridges, controlling fluid flow.
- Developed a portable colorimetric reader for valve operation, signal quantification, and data transmission.
- Implemented a valve malfunction detection mechanism.
Main Results:
- Demonstrated reliable operation of individual paper valves (97% success rate) and the entire μPAD (93% success rate).
- Achieved a low limit of detection (LOD) of 27 pM for rabbit IgG using direct ELISAs.
- Successfully quantified tumor necrosis factor (TNF)-α levels in rat laryngeal tissue using sandwich ELISAs, showing comparable results to conventional methods.
Conclusions:
- The developed μPAD with SMP-actuated valves provides a reliable and automated platform for multi-step immunoassays.
- The integrated system, including a portable reader, supports telemedicine applications through wireless data transmission.
- This technology holds significant potential for low-cost, automated diagnostics in resource-limited settings.
