Nav: Home

Cryo-force spectroscopy reveals the mechanical properties of DNA components

February 08, 2019

Physicists from the University of Basel have developed a new method to examine the elasticity and binding properties of DNA molecules on a surface at extremely low temperatures. With a combination of cryo-force spectroscopy and computer simulations, they were able to show that DNA molecules behave like a chain of small coil springs. The researchers reported their findings in Nature Communications.

DNA is not only a popular research topic because it contains the blueprint for life - it can also be used to produce tiny components for technical applications. In a process known as DNA origami, scientists can manipulate the genetic material in such a way that folding the DNA strands creates tiny two- and three-dimensional structures. These can be used, for example, as containers for pharmaceutical substances, as conductive tubes and as highly sensitive sensors.

Measurement at low temperatures

To be able to form the desired shapes, it is important to be familiar with the structure, the elasticity and the binding forces of the DNA components being used. These physical parameters cannot be measured at room temperature, because the molecules are constantly in motion.

The same is not true at low temperatures: the team led by Professor Ernst Meyer from the Swiss Nanoscience Institute and the University of Basel's Department of Physics have now used cryo-force microscopy for the first time to characterize DNA molecules and examine their binding forces and elasticity.

Detached piece by piece

The scientists placed only few nanometer long DNA strands containing 20-cytosine nucleotides on a gold surface. At a temperature of 5 Kelvin, one end of the DNA strand was then pulled upwards using the tip of an atomic force microscope. In the process, the individual components of the strand freed themselves from the surface little by little. This enabled the physicists to record their elasticity as well as the forces required to detach the DNA molecules from the gold surface.

"The longer the detached piece of DNA, the softer and more elastic the DNA segment becomes," explains lead author Dr. Rémy Pawlak. This is because the individual components of the DNA behave like a chain of multiple coil springs connected to one another. Thanks to the measurements, the researchers were able to determine the spring constant for the individual DNA components.

Computer simulations clarify that the DNA is detached discontinuously from the surface. This is due to the breaking up of bonds between the cytosine bases and the DNA backbone from the gold surface, and their abrupt movements over the gold surface. The theoretical elasticity values correlate very closely with the experiments and confirm the model of serially arranged springs.

Snapshots provide insight

The studies confirm that cryo-force spectroscopy is very well suited to examining the forces, elasticity and binding properties of DNA strands on surfaces at low temperatures.

"As with cryogenic electron microscopy, we take a snapshot with cryo-force spectroscopy, which gives us an insight into the properties of DNA," explains Meyer. "In future, we could also make use of scanning probe microscope images to determine nucleotide sequences."
-end-


University of Basel

Related Dna Articles:

Penn State DNA ladders: Inexpensive molecular rulers for DNA research
New license-free tools will allow researchers to estimate the size of DNA fragments for a fraction of the cost of currently available methods.
It is easier for a DNA knot...
How can long DNA filaments, which have convoluted and highly knotted structure, manage to pass through the tiny pores of biological systems?
How do metals interact with DNA?
Since a couple of decades, metal-containing drugs have been successfully used to fight against certain types of cancer.
Electrons use DNA like a wire for signaling DNA replication
A Caltech-led study has shown that the electrical wire-like behavior of DNA is involved in the molecule's replication.
Switched-on DNA
DNA, the stuff of life, may very well also pack quite the jolt for engineers trying to advance the development of tiny, low-cost electronic devices.
Researchers are first to see DNA 'blink'
Northwestern University biomedical engineers have developed imaging technology that is the first to see DNA 'blink,' or fluoresce.
Finding our way around DNA
A Salk team developed a tool that maps functional areas of the genome to better understand disease.
A 'strand' of DNA as never before
In a carefully designed polymer, researchers at the Institute of Physical Chemistry of the Polish Academy of Sciences have imprinted a sequence of a single strand of DNA.
Doubling down on DNA
The African clawed frog X. laevis genome contains two full sets of chromosomes from two extinct ancestors.
'Poring over' DNA
Church's team at Harvard's Wyss Institute for Biologically Inspired Engineering and the Harvard Medical School developed a new electronic DNA sequencing platform based on biologically engineered nanopores that could help overcome present limitations.

Related Dna Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Digital Manipulation
Technology has reshaped our lives in amazing ways. But at what cost? This hour, TED speakers reveal how what we see, read, believe — even how we vote — can be manipulated by the technology we use. Guests include journalist Carole Cadwalladr, consumer advocate Finn Myrstad, writer and marketing professor Scott Galloway, behavioral designer Nir Eyal, and computer graphics researcher Doug Roble.
Now Playing: Science for the People

#529 Do You Really Want to Find Out Who's Your Daddy?
At least some of you by now have probably spit into a tube and mailed it off to find out who your closest relatives are, where you might be from, and what terrible diseases might await you. But what exactly did you find out? And what did you give away? In this live panel at Awesome Con we bring in science writer Tina Saey to talk about all her DNA testing, and bioethicist Debra Mathews, to determine whether Tina should have done it at all. Related links: What FamilyTreeDNA sharing genetic data with police means for you Crime solvers embraced...