Electroosmotic flow velocity in DNA modified nanochannels

Area of Science:

• Microfluidics
• Surface Chemistry
• Physical Chemistry

Background:

• Electroosmotic flow (EOF) is crucial for fluid manipulation in microchannels.
• Surface modification of microchannels impacts EOF characteristics.
• Understanding EOF in nanoscale devices is essential for advanced applications.

Purpose of the Study:

• To systematically investigate electroosmotic flow (EOF) in DNA-grafted hard polydimethylsiloxane (h-PDMS) channels.
• To explore the influence of DNA type, incubation time, pH, ionic concentration, and UV illumination on EOF velocity.
• To analyze EOF behavior across a range of channel sizes (50 nm to 2.5 μm).

Main Methods:

• Utilized the current-slope method for systematic EOF velocity measurements.
• Experimentally studied the effects of various parameters on EOF in modified and pristine channels.
• Investigated EOF in h-PDMS channels grafted with different DNA types.

Main Results:

• DNA grafting density and surface charge, influenced by DNA type and incubation time, significantly affect EOF velocity.
• pH effects on EOF are less pronounced in DNA-modified channels compared to pristine channels.
• UV illumination substantially increases EOF velocity in DNA-modified channels but has minimal effect on pristine channels.
• EOF velocity shows channel size dependence at low ionic concentrations but becomes independent at high concentrations.
• DNA brushes enhance EOF velocity under high ionic concentration and thin electric double layer (EDL) conditions.

Conclusions:

• DNA surface modification offers a tunable approach to control EOF in microfluidic devices.
• UV treatment presents a promising method for enhancing EOF in DNA-modified microchannels.
• The interplay between ionic concentration, channel size, and surface modification dictates EOF behavior, particularly concerning EDL effects.