How DNA molecules move in fluids

A research team from Saudi Arabia has developed a new analytical method that can capture the motion of macromolecules such as DNA in a homogenous fluid¹. 

The new method, known as lattice occupancy analysis, reveals an unexpected, non-random motion of DNA molecules.

Brownian motion — the seemingly erratic movement of particles suspended in a fluid — plays a key role in the transportation of small molecules and proteins in a living cell. It also controls the motion of small molecules inside catalytically active materials. These processes, the researchers say, could be better characterized by using the new method.   

“The new method could also be applicable to a broad range of studies related to Brownian motion ... including molecules observed in a fluid,” says Satoshi Habuchi, co-corresponding author of the study from the King Abdullah University of Science and Technology (KAUST), Saudi Arabia.  

Using single-molecule fluorescence microscopy, Habuchi and his teammate Maged F. Serag studied the pattern of the diffusive motion of DNA molecules in a fluid. They observed the movement at length scales larger than the size of the molecules. 

Detailed analysis demonstrated that the molecules’ non-random diffusion rate is what triggers the peculiar motion of the DNA molecules. 

According to the researchers, the DNA molecules used in this study can also be considered as a model system for studying the motion of semi-flexible polymer molecules in a specific medium.

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