Simple Bulk Readout of Digital Nucleic Acid Quantification Assays

Area of Science:

• Biotechnology
• Molecular Biology
• Genomics

Background:

• Digital assays offer high sensitivity for detecting rare cells and quantifying nucleic acid molecules.
• Current digital assay methods are limited by high costs and specialized equipment requirements.
• Existing digital assays are not routinely applied due to these accessibility barriers.

Purpose of the Study:

• To present a simplified readout method for digital droplet assays using conventional real-time PCR instruments.
• To enable bulk fluorescence measurement of droplet-based digital assays, reducing reliance on specialized hardware.
• To enhance the accessibility and routine application of digital assay technologies.

Main Methods:

• Developed a bulk fluorescence readout technique for droplet-based digital assays.
• Utilized a conventional real-time PCR instrument for assay measurement.
• Characterized assay performance with synthetic droplet mixtures and droplet digital multiple displacement amplification (MDA).

Main Results:

• The simplified method successfully measures bulk fluorescence from digital droplet assays.
• Performance was validated using synthetic mixtures and a droplet digital MDA assay.
• The methodology provides the benefits of partitioned assays without specialized readout instrumentation.

Conclusions:

• This bulk readout method simplifies and accelerates digital assay procedures, including digital PCR.
• It significantly lowers the barrier to entry for digital assay technologies by using standard equipment.
• The approach holds promise for applications in pharmaceutical quality control and astrobiology, despite a reduced dynamic range compared to droplet-counting platforms.