Microfluidic assays for DNA manipulation based on a block copolymer immobilization strategy

Area of Science:

• Biophysics
• Molecular Biology
• Microfluidics

Background:

• Investigating DNA biophysics and protein interactions requires effective methods for manipulating and visualizing isolated DNA strands.
• Current methods may suffer from noise due to non-specific adsorption of molecules.

Purpose of the Study:

• To develop a novel method for manipulating and visualizing single DNA molecules within microfluidic channels.
• To create a surface functionalization strategy that minimizes non-specific adsorption and enhances single-molecule detection.

Main Methods:

• Utilized a block copolymer surface functionalization strategy with poly(l-lysine-graft-polyethylene glycol) (PLL-g-PEG) to coat microfluidic channels.
• Immobilized single lambda-phage DNA molecules and extended them using molecular combing and hydrodynamic flow.
• Ensured DNA extension did not exceed contour length, attributed to low surface tension of the coated surface.

Main Results:

• The PLL-g-PEG coated surface demonstrated passivity to adsorption, minimizing background noise.
• Successful immobilization and extension of single DNA molecules were achieved.
• The method proved effective for visualizing DNA under different extension forces.

Conclusions:

• The developed microfluidic method offers a robust platform for single-molecule DNA manipulation and visualization.
• The PLL-g-PEG coating enhances single-molecule detection capabilities and stability.
• This technique is proposed for exploring DNA-protein interactions due to its simplicity and compatibility with microfluidics.