An injection molded microchip for nucleic acid purification from 25 microliter samples using isotachophoresis

Area of Science:

• Biotechnology
• Analytical Chemistry
• Microfluidics

Background:

• Nucleic acid purification is critical for molecular diagnostics.
• Existing methods can be time-consuming or require large sample volumes.
• Microfluidic devices offer potential for faster, more efficient purification.

Purpose of the Study:

• To develop and validate a novel microchip device for rapid nucleic acid purification.
• To assess the efficiency and compatibility of the purified nucleic acids for downstream applications.

Main Methods:

• Utilized isotachophoresis (ITP) on a microchip device with optimized channel dimensions and geometry.
• Incorporated a capillary barrier for sample loading and a separated buffering reservoir to manage electrolysis.
• Fabricated the device using injection molding of PMMA and COC plastics.
• Quantified nucleic acid recovery using fluorescent assays and validated DNA purity with quantitative PCR (qPCR).

Main Results:

• Achieved an average nucleic acid recovery efficiency of 81% for masses ranging from 250pg to 250ng.
• Demonstrated successful purification of DNA from whole blood samples.
• Confirmed the PCR compatibility of the purified DNA, enabling successful qPCR amplification.

Conclusions:

• The novel microchip device enables efficient and rapid nucleic acid purification from small biological sample volumes.
• The device design mitigates common microfluidic challenges like Joule heating and dispersion.
• The purified nucleic acids are suitable for sensitive downstream molecular analyses such as qPCR.