Researchers develop breakthrough technique for non-invasive electron microscopy for soft materials

July 25, 2016 , US Department of Energy
CLAIRE extends the resolution of electron microscopy to allow high-resolution, non-invasive imaging of soft matter. Soft aluminum nanostructures on polymer films were imaged. The inset shows a detailed view of a cluster of six aluminum nanostructures. These films could not have been directly imaged with traditional electron microscopy. Credit: US Department of Energy

Using the Molecular Foundry's imaging capabilities, scientists developed a technique, called "CLAIRE," that allows the incredible resolution of electron microscopy to be used for non-invasive imaging of biomolecules and other soft matter. The new technique offers both clarity and speed.

CLAIRE could lead to the understanding of key biological processes and help accelerate the development of new technologies such as high-efficiency photovoltaic cells.

Soft matter encompasses a broad swath of materials, including liquids, polymers, gels, foam and—most importantly—biomolecules. At the heart of soft materials, governing their overall properties and abilities, are the interactions of nano-sized components. Observing the dynamics behind these interactions is critical to understanding key biological processes, such as protein crystallization and metabolism, and could help accelerate the development of important new technologies, such as artificial photosynthesis or high-efficiency photovoltaic cells. Observing these dynamics at sufficient resolution has been a major challenge, but scientists are now meeting this challenge with a new non-invasive nanoscale imaging technique that goes by the acronym of CLAIRE.

CLAIRE stands for "cathodoluminescence activated imaging by resonant energy transfer" and combines elements of optical and scanning microscopy into a single imaging platform. The system utilizes an ultrathin scintillating film that is placed between the and sample. When the film is excited by the electron beam, it transfers energy and causes the sample to radiate. In this way, an image can be formed that is not restricted by the optical diffraction limit.

Invented by users of the Molecular Foundry, CLAIRE extends the incredible resolution of to the dynamic imaging of . The research team demonstrated CLAIRE's imaging capabilities by applying the technique to aluminum nanostructures and polymer films that could not have been directly imaged with electron microscopy. They obtained optical of aluminum nanostructures with 46-nanometer resolution and then validated the non-invasiveness of CLAIRE by imaging a conjugated polymer film. The high , speed, and non-invasiveness could transform the way key biomolecular interactions are studied.

More information: Connor G. Bischak et al. Cathodoluminescence-Activated Nanoimaging: Noninvasive Near-Field Optical Microscopy in an Electron Microscope, Nano Letters (2015). DOI: 10.1021/acs.nanolett.5b00716

Journal information: Nano Letters

Provided by US Department of Energy