Stretching of single DNA molecules caused by accelerating flow on a microchip

Area of Science:

• Biophysics
• Fluid Dynamics
• Polymer Physics

Background:

• Investigating DNA behavior under external forces is crucial for understanding cellular processes.
• Microfluidic devices offer controlled environments for single-molecule studies.

Purpose of the Study:

• To investigate DNA elongation induced by fluidic stress.
• To elucidate the physical mechanism of DNA stretching in accelerating flow.

Main Methods:

• Single-DNA observation using fluorescence microscopy on a microfluidic chip.
• Monitoring T4 DNA molecule (166 kbp) stretching in areas of accelerating flow.
• Theoretical modeling of a coarse-grained nonlinear elastic polymer chain under shear stress.

Main Results:

• DNA long-axis length increased sigmoidal with increasing flow acceleration (shear).
• Observed DNA elongation dependent on shear stress magnitude along the DNA chain.
• Theoretical model supported experimental findings on DNA stretching.

Conclusions:

• Fluidic shear stress significantly elongates DNA molecules.
• The sigmoidal DNA elongation response is linked to the magnitude of flow acceleration.
• The study provides insights into polymer dynamics under flow-induced stress.