a story lives forever
Sign in
Form submission failed!

Stay signed in

Recover your password?
Form submission failed!

Web of Stories Ltd would like to keep you informed about our products and services.

Please tick here if you would like us to keep you informed about our products and services.

I have read and accepted the Terms & Conditions.

Please note: Your email and any private information provided at registration will not be passed on to other individuals or organisations without your specific approval.

Video URL

You must be registered to use this feature. Sign in or register.


Using nanotechnology to do evolutionary experiments


Using primers to see single particles
Manfred Eigen Scientist
Comments (0) Please sign in or register to add comments

That's one thing, to pick up single molecules, that's fine, but if there are other molecules around...

[Q] If you want to look at the virus in the blood.

If you want to not only see single molecules but also seeing low concentrations. We will come to the virus later. I want to see a single virus particle in a millilitre of blood, or when I divide my thing it's only a few microlitre, and I want to see that... that particle. How can I do this? Well, a virus is a nucleic acid.  The genome of a virus is... the AIDS virus is an RNA molecule. So, I can make a primer. I have already said what a primer is... it's a sequence, let's say of twenty nucleotides... twenty monomers, which is complementary to a part of the sequence you are looking for, and since the AIDS virus sequences are known we can easily make such primers towards certain parts of the AIDS RNA... of the HIV RNA. So, those primers we can couple with the fluorescing group. In other words we put on a dye, a fluorescing dye. Now, there comes a problem. It turns out that you need at least a certain number of these primers for them to bind to the target... for those who know concentration values it's about nanomolar, 10-9 molar. If you go below with your primer concentration it wouldn't bind any more. Why not? Because the nucleic acid is folded, and it has to unfold in order to let the primer completely bind to it; and that folding is a internal first order reaction, the binding is a second order reaction combination with the molecule, and that needs a certain concentration to compete.

But what I want to do is I want to see a concentration much lower than 10-9 molar, I want to see a single virus particle. One virus particle per millilitre, well one virus particle per litre is about 10-24 molar, per millilitre is about 10-20, 10-21 molar, or one per microlitre is 10-18 molar. So I want to see when I divide my sample into microlitre probes into which I focus my laser light, I could see in fact concentrations as low as 10-18 molar, but they are a billion times as large as the primer concentration, and the primer of course contains a dye and fluorescence too.

So there are ways you have to use electric fields, you have to trap the molecule, you have to use different charges for the primer and the large molecule, there are now new polymers which are complementary which are called PNA. They are like are like RNA but have a peptide backbone which is not negatively charged. So you have to use all those tricks now to manipulate the single molecule in order to get them where you want to measure them. And that's a method which has been worked out, so that I can say nowadays we can use nanotechnology... we can manufacture technical devices in the range of micron... micrometre... where we can try to manipulate molecules using electric fields to carry them through and use laser beams which are focused into such a small area.

Nobel Prize winning German biophysical chemist, Manfred Eigen (1927-2019), was best known for his work on fast chemical reactions and his development of ways to accurately measure these reactions down to the nearest billionth of a second. He published over 100 papers with topics ranging from hydrogen bridges of nucleic acids to the storage of information in the central nervous system.

Listeners: Ruthild Winkler-Oswatitch

Ruthild Winkler-Oswatitsch is the eldest daughter of the Austrian physicist Klaus Osatitsch, an internationally renowned expert in gas dynamics, and his wife Hedwig Oswatitsch-Klabinus. She was born in the German university town of Göttingen where her father worked at the Kaiser Wilhelm Institute of Aerodynamics under Ludwig Prandtl. After World War II she was educated in Stockholm, Sweden, where her father was then a research scientist and lecturer at the Royal Institute of Technology.

In 1961 Ruthild Winkler-Oswatitsch enrolled in Chemistry at the Technical University of Vienna where she received her PhD in 1969 with a dissertation on "Fast complex reactions of alkali ions with biological membrane carriers". The experimental work for her thesis was carried out at the Max Planck Institute for Physical Chemistry in Göttingen under Manfred Eigen.

From 1971 to the present Ruthild Winkler-Oswatitsch has been working as a research scientist at the Max Planck Institute in Göttingen in the Department of Chemical Kinetics which is headed by Manfred Eigen. Her interest was first focused on an application of relaxation techniques to the study of fast biological reactions. Thereafter, she engaged in theoretical studies on molecular evolution and developed game models for representing the underlying chemical proceses. Together with Manfred Eigen she wrote the widely noted book, "Laws of the Game" (Alfred A. Knopf Inc. 1981 and Princeton University Press, 1993). Her more recent studies were concerned with comparative sequence analysis of nucleic acids in order to find out the age of the genetic code and the time course of the early evolution of life. For the last decade she has been successfully establishing industrial applications in the field of evolutionary biotechnology.

Tags: virus, nucleic acid, AIDS, HIV, RNA molecule, PNA, Peptide nucleic acid, ribonucleic acid, fluorescing dye, primers, nanotechnology

Duration: 4 minutes, 26 seconds

Date story recorded: July 1997

Date story went live: 29 September 2010