Navigation Links
Detecting mirror molecules

Harvard physicists have developed a novel technique that can detect molecular variants in chemical mixtures greatly simplifying a process that is one of the most important, though time-consuming, processes in analytical chemistry.

As described in a paper in Nature, post-doctoral researcher David Patterson, Professor of Physics John Doyle and Dr. Melanie Schnell of the Center for Free-Electron Laser Science (CFEL) in Hamburg, Germany developed a system that relies on finely-tuned microwave fields to identify molecular variants apart, and to determine how much variant is in a mixture.

The ability to tell such variants apart, researchers said, is critical because many chemical compounds exist in two forms, each of which is a mirror image of the other. Such molecules are called chiral, from the ancient Greek for hand, and are often described as being either "right-handed" or "left-handed."

Knowing whether a molecule is right- or left-handed, scientists say, is important, because each type of molecule behaves differently in chemical reactions. Much of biology, for example, is predicated on the idea that amino acids are "left-handed," while sugar molecules are "right-handed."

"The 'wrong' sort of a compound can function completely differently in an organism," explains Schnell, who leads an independent Max Planck research group for structure and dynamics of molecules at CFEL. "In the best case it is just ineffective. In the worst case it is toxic."

The challenge, however, is that telling the two variants of a chiral molecule apart is no easy job.

A common way to discern between them is to shine linear polarised light through them. While one variant will turn the plane of polarisation to the left, the other will turn it to the right. The problem with that method, researchers say, is that it produces rather weak effects, and can only be used on liquid samples, and it can be difficult to use on samples that contain a mixture of many different species.

"It's an extremely common situation to have a mixture say a blood sample, or something from a complex chemical process - that contains a left-handed version of some compounds and a right handed version others for example, left handed alanine along with right handed citric acid. Optical polarimetery really struggles with such a situation if there's more than about 3 compounds, it's pretty hopeless. We hope our technique will provide a tool which can produce a complete analysis of such a mixture".

In contrast, the method developed by Patterson, Doyle and Schnell, by comparison, relies on what is called the electric dipole moment of each molecule, or the way each interacts with an external electric field. As a consequence of their mirror-image construction, molecules rotate in opposite directions when certain microwave fields are applied and this results in a signature which tells if the molecules are left or right handed.

To measure the dipole moment of molecules, the team used microwaves.

Researchers fed a gaseous sample into a chamber, then cooled it to -226 degrees Celsius. As the cold gas interacted with a precisely-tuned microwave fieldwhich caused the molecules to spin and give off their own microwave radiation. By monitoring those emissions, researchers are able to tell whether the molecules are right- or left-handed.

The researchers tested their method using the organic compound 1,2-propanediol, and were able to reliably differentiate between the two variants, but also determine the ratio of variants in a mixture by finely-tuning the microwave frequency.

"We can soon measure mixtures of different compounds and determine the enantiomer ratios of each," explains Schnell. In a next step the researchers plan to apply the technique in a broadband spectrometer at CFEL that could then measure the ratios in other mixtures of substances.

In the longer run, the method opens the exciting perspective to develop a technique for separating variants a technique that, if successful, could be of great interest to a number of industries, particularly the development of new pharmaceuticals.


Contact: Peter Reuell
Harvard University

Related biology news :

1. Detecting breast cancers fingerprint in a droplet of blood
2. By detecting smallest virus, researchers open possibilities for early disease detection
3. Texas Biomed reports faster, more economical method for detecting bioterror threats
4. Holding a mirror to brain changes in autism
5. Iowa State, Ames Lab researchers invent new tool to study single biological molecules
6. New model gives hands-on help for learning the secrets of molecules
7. Weighing molecules 1 at a time
8. Nano-velcro clasps heavy metal molecules in its grips
9. Researchers develop new stamping process to pattern biomolecules at high resolution
10. A class of RNA molecules protects germ cells from damage, Penn vet researchers show
11. Dance of water molecules turns fire-colored beetles into antifreeze artists
Post Your Comments:
(Date:10/1/2015)... 2015  Biometrics includes diverse set of technologies ... such as fingerprints, eye retinas, facial patterns, voice ... technology has been constantly increasing in ... In addition to the most prominent popular method ... means of biometric authentication are rapidly gaining traction ...
(Date:9/29/2015)... , Sept. 29, 2015 News ... productivity while also saving energy , Minimized design ... Low Power Active Mode and embedded Fujitsu PalmSecure authentication ... Fujitsu today shows that good things come ... refreshed models to its enterprise desktop and mobile portfolio. ...
(Date:9/28/2015)... , September 28, 2015 ... expected to reach USD 12.03 billion by 2020, growing ... Technological advancements such as Backside Illumination (BSI) technique to ... over the forecast period.      (Logo: ... of the chip to reduce loss and, thus, reduce ...
Breaking Biology News(10 mins):
(Date:10/10/2015)... 10. Oktober, 2015 Am 8. Oktober ... Demokratischen Partei für Kalifornien) ihre Würdigung der International ... in die Aufzeichnungen des Kongresses eintragen lassen. Die ... Association (PPTA) und ihren Mitgliedsunternehmen unterstützt. Ihre ... des Bewusstseins über Plasmaspenden weltweit , Würdigung ...
(Date:10/9/2015)...  DePuy Synthes Trauma* announced today the U.S. launch ... Technology**, the only pre-hydrated demineralized cancellous bone tissue matrix ... ankle, hand and wrist), including fusion, and for filling ... 2015 Orthopaedic Trauma Association (OTA) Annual Meeting. ... bone growth) and osteoinductive 2,3 (stimulates new bone ...
(Date:10/8/2015)... and CARDIFF, UK (PRWEB) , ... October 08, 2015 , ... ... technology to literally see inside the living brain, providing a new tool to study ... The work is reported by Woo June Choi and Ruikang Wang of the UW ...
(Date:10/8/2015)... 8, 2015  ATCC, the premier global biological materials ... been selected by The Michael J. Fox Foundation for ... academic, pharmaceutical, and biotechnology organizations committed to speed a ... United States , and more than 5 million ... United States , and more than 5 million ...
Breaking Biology Technology: