“Raman scattering provides information on the ways molecules vibrate, which is equivalent to taking their fingerprint. It’s a bit like a bar code,” said the internationally renowned professor. “Raman signals are specific for each molecule and thus useful in identifying these molecules.”
Richard Martel and his research team at the Department of Chemistry of the Université de Montréal have discovered a method to improve detection of the infinitely small. Their discovery is presented in the November 24 online edition of the journal Nature Photonics. Credit: Universite de Montreal
Applications of the discovery: retail, banks, hospitals, etc.
The discovery by Martel’s team is that Raman scattering of dye-nanotube particles is so large that a single particle of this type can be located and identified. All one needs is an optical scanner capable of detecting this particle, much like a fingerprint.
“By incorporating these nanoparticles in an object, you can make it perfectly traceable,” he said. Due to their unique structure, carbon nanotubes, which are electrically conductive, can be used as containers for various molecules. Coupled with a dye, these nanoprobes can increase the complexity and strength of the received signal.
Nanoprobes, which are composed of around one hundred dye molecules aligned inside a cylinder, are 50,000 times smaller than a human hair. They are about one nanometre (nm) in diameter and 500 nm long, yet they send a Raman signal one million times stronger than the other molecules in the surrounding.
According to Professor Martel, the applications from this discovery are numerous. In medicine, nanoprobes could lead to improved diagnostics and better treatment by adhering to the surface of diseased cells. These specifically modified nanoprobes could, in effect, be grafted to bacteria or even proteins, allowing them to be easily identified.
One could also imagine custom officers scanning our passports with Raman multispectral mode (i.e., involving several signals). Nanoprobes could also be used in banknote ink, making counterfeiting virtually impossible.
The beauty of it, said Martel, is that the phenomenon is generalized, and many types of dyes can be used to make nanoprobes or tags, whose “bar codes” are all different. “So far, more than 10 different tags have been made, and it seems the sky’s the limit,” he said. “We could, in theory, create as many of these tags as there are bacteria and use this principle to identify them with a microscope operating in Raman mode.”
The story of Raman signals
Raman scattering mode is an optical phenomenon discovered in 1928 by the physicist Chandrasekhara Venkata Raman. The effect involves the inelastic scattering of photons, i.e. the physical phenomenon by which a medium can modify the frequency of the light impinging on it. The difference corresponds to an exchange of energy (wavelength) between the light beam and the medium. In this way, scattered light does not have the same wavelength as incidental light. The technique has become widely used since the advent of the laser in the industry and for research .
But until now, molecular Raman signals have been too weak to serve the needs of optical imaging effectively. So researchers have used other more sensitive techniques but which are less specific because they have no “bar code.” “It is technically possible, however, to enhance the Raman signals of molecules using rough metallic surfaces,” said Martel. “But their sizes limit the applications of Raman spectroscopy and imaging.”
By aligning dye molecules encapsulated in carbon nanotubes, the researchers were able to amplify the Raman signals of these molecules, which until now have not been strong enough to detect. The article presents experimental evidence of extraordinary scattering of visible light on a nanoparticle.Besides Richard Martel, E. Gaufrès, N. Y. Wa Tang, F. Lapointe, J. Cabana, M. A. Nadon, N. Cottenye, F. Raymond, all of the Université de Montréal, and T. Szkopek, University McGill, contributed to this discovery.
William Raillant-Clark | alfa
Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München
Second research flight into zero gravity
21.10.2016 | Universität Zürich
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.
Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
21.10.2016 | Health and Medicine
21.10.2016 | Information Technology
21.10.2016 | Materials Sciences