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 capabilities, 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 this challenge is now being met 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.” Invented by researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley, CLAIRE extends the extremely high resolution of electron microscopy to the dynamic imaging of soft matter.
“Traditional electron microscopy damages soft materials and has therefore mainly been used to provide topographical or compositional information about robust inorganic solids or fixed sections of biological specimens,” says chemist Naomi Ginsberg, who leads CLAIRE’s development and holds appointments with Berkeley Lab’s Physical Biosciences Division and its Materials Sciences Division, as well as UC Berkeley’s departments of chemistry and physics.
“CLAIRE allows us to convert electron microscopy into a new non-invasive imaging modality for studying soft materials and providing spectrally specific information about them on the nanoscale.”
Ginsberg is also a member of the Kavli Energy NanoScience Institute (Kavli-ENSI) at Berkeley. She and her research group recently 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.
“What microscopic defects in molecular solids give rise to their functional optical and electronic properties? By what potentially controllable process do such solids form from their individual microscopic components, initially in the solution phase? The answers require observing the dynamics of electronic excitations or of molecules themselves as they explore spatially heterogeneous landscapes in condensed phase systems,” Ginsberg says.
“In our demonstration, we obtained optical images of aluminum nanostructures with 46 nanometer resolution, then validated the non-invasiveness of CLAIRE by imaging a conjugated polymer film. The high resolution, speed and non-invasiveness we demonstrated with CLAIRE positions us to transform our current understanding of key biomolecular interactions.”