Rapid and variable-volume sample loading in sieving electrophoresis microchips using negative pressure combined with...

Area of Science:

• Microfluidics
• Analytical Chemistry
• Biotechnology

Background:

• Chip-based sieving electrophoresis offers miniaturized separation capabilities.
• Efficient and controllable sample loading is crucial for microfluidic device performance.

Purpose of the Study:

• To develop a rapid and variable-volume sample loading scheme for chip-based sieving electrophoresis.
• To integrate negative pressure with electrokinetic force for enhanced sample introduction.

Main Methods:

• Utilized a low-cost microvacuum pump and a single potential supply for sample loading.
• Employed linear polyacrylamide (LPA) and hydroxyethylcellulose (HEC) as sieving materials.
• Applied subambient pressure to the sample waste reservoir to draw sample and buffer solutions.

Main Results:

• Achieved rapid sample loading with variable plug volumes controlled by loading time.
• Demonstrated low sample consumption (1.7 x 10^2 nL) and fast analyte transport (0.024 s).
• Produced high-quality, non-distorted sample plugs for injection.

Conclusions:

• The developed method offers a versatile and efficient approach for sample loading in chip-based sieving electrophoresis.
• The system shows potential for improving throughput, repeatability, and sensitivity.
• This technique facilitates precise control over sample plug volume and quality.