Non-destructive microscopy technique created
6 Apr 2016 by Evoluted New Media
The ability to view nanoscale objects and processes without destroying them is now possible after research carried out at the Oak Ridge National Laboratory in the US.
The ability to view nanoscale objects and processes without destroying them is now possible after research carried out at the Oak Ridge National Laboratory in the US.
Imaging techniques that use X-rays or electron beams can alter, or even destroy the sample.
This new technique is called scanning microwave impedance microscopy (sMIM). A sample was encapsulated in liquid inside a chamber with a membrane-made window 8 to 50nm thick. A scanning probe microscope was moved across this membrane injecting microwaves into the chamber and a high resolution map of the image was created from where the microwaves were transmitted or blocked.
Alexander Tselev, study leader, said: “Our imaging is non-destructive and free from the damage frequently caused to samples, such a living cells or electrochemical processes, by imaging with X-ray or electron beams. Its spatial resolution is better than what is achievable with optical microscopes for similar in-liquid samples.”
The injected microwaves are 100 million times weaker than those used in a home microwave and oscillate in opposite directions several billions times every second. This means potentially destructive chemical reactions cannot occur as the technique produces negligible heat and does not damage the sample.
The method could allow scientists to watch processes as they occur, allowing chemical reactions to be viewed as they unfold – rather than stopping the reactions at various stages to observe them.
Andrei Kolmakov, senior author from the National Institute of Standards and Technology (NIST), said: “At NIST, we developed environmental chambers with ultra-thin membranes to perform electron microscopy and other analytical techniques in liquids. Conversations between the ORNL and NIST scientists resulted in the idea to try non-destructive microwaves so the environmental chambers could be used for broader studies.”
The scientists will now try to improve the sensitivity and spatial resolution of the system. A possible way to do this will be to make the wall of the environmental chamber thinner using graphene or hexagonal boron nitride.
The scientists’ work was published in ACS Nano.
