A 3D paper microfluidic device for enzyme-linked assays: Application to DNA analysis

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Microfluidics

Background:

• Paper-based analytical devices (PADs) offer low-cost diagnostics.
• Enzyme-linked assays are crucial for sensitive analyte detection.
• Existing methods may lack sensitivity or require complex instrumentation.

Purpose of the Study:

• To develop a microfluidic enzyme-linked paper analytical device (μEL-PAD).
• To demonstrate the μEL-PAD's capability for sensitive DNA detection.
• To compare μEL-PAD performance against traditional lateral flow assays (LFAs).

Main Methods:

• Utilized a wash-free sandwich coupling for bead/analyte/enzyme complex formation.
• Employed a vertical flow device with wax-printed paper and nitrocellulose membrane.
• Quantified results using open-source smartphone software after chromogenic substrate interaction.

Main Results:

• Achieved a limit of detection (LOD) <10 genome copies/μL for Staphylococcus epidermidis DNA.
• Demonstrated a limit of quantification (LOQ) <10 genome copies/μL.
• Outperformed traditional LFAs by 70-fold (LOD) and 1000-fold (LOQ).

Conclusions:

• The μEL-PAD is a universal, sensitive, and quantitative paper-based platform.
• It enables high-sensitivity detection of analytes like proteins and nucleic acids.
• The device shows promise for low-cost, simple, and sensitive point-of-care testing.