3D-printed devices for multiplexed semi-quantitative competitive lateral flow immunoassays.

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Assay Development

Background:

• Lateral flow immunoassays (LFIAs) are prevalent for rapid, point-of-need diagnostics but face challenges in multiplexing and semi-quantitative analysis, especially for small molecules.
• Current multiplexed LFIAs often require large sample volumes and multiple test strips, increasing device size and complexity.
• Competitive immunoassay formats for low molecular weight compounds are particularly constrained by spatial limitations on planar membranes.

Purpose of the Study:

• To develop novel 3D-printed devices for multiplexed lateral flow immunoassays (LFIAs).
• To enable simultaneous, semi-quantitative, naked-eye detection of multiple analytes using minimal sample volume.
• To overcome the spatial constraints of traditional planar LFIAs.

Main Methods:

• Designed two 3D-printed devices with eight assay lanes each, accommodating both backed and unbacked nitrocellulose membranes.
• Utilized inkjet printing to deposit capture reagents as text symbols for intuitive result expression.
• Controlled concentration thresholds for text readability to achieve semi-quantitative analysis.
• Employed 8-OHdG, caffeine, and acetaminophen as model analytes for proof of concept.

Main Results:

• Successfully demonstrated simultaneous detection of caffeine and acetaminophen in mixed solutions using a small sample volume (350 μL).
• Achieved visual distinction of four concentration levels for both caffeine and acetaminophen without crosstalk.
• Validated the use of inkjet-printed text symbols for intuitive, semi-quantitative result interpretation.
• Showcased the capability of 3D-printed LFIAs to handle multiplexed assays effectively.

Conclusions:

• 3D-printed LFIA devices offer a viable solution to spatial limitations in multiplexed assay development.
• This technology enables efficient, simultaneous, and semi-quantitative detection of multiple analytes with minimal sample volume.
• The developed devices hold significant potential for point-of-need diagnostics, particularly for low molecular weight compounds and drug testing.