From nearly 100 submissions for the 2016 WITec Paper Awards, the jury selected the three best publications: they document how through correlative microscopy information on the chemical and structural composition of a material can be linked for a more comprehensive understanding. The annual awards recognize outstanding scientific work published the preceding year that employed a WITec device as part of its experimental setup. The evaluation criteria include the significance of the results for the scientific community and the originality of the techniques used.
The 2016 Gold Paper Award is presented to Admir Masic (right in image) from the Max-Planck-Institute of Colloids and Interfaces (Potsdam, Germany) and James Weaver (middle) from Harvard University (Cambridge, USA) for their microscopic analysis of the teeth of the red sea urchin by WITec representitive Tavis Ezell (left). Its razor-sharp, extremely hard and lifelong-regenerating biting tools have long been regarded as a model of biomineralization. To analyze the molecular and elemental composition of the teeth, the researchers used confocal Raman microscopy and energy-dispersive X-ray spectroscopy (EDX). Atomic Force Microscopy (AFM) was used for high-resolution structural characterization. Chemical and structural data and images could be perfectly correlated: the hardest part of the T-shaped, calcium carbonate (calcite) teeth contains the highest proportion of magnesium, while their interior contains the least magnesium and predominately organic material. They conclude their report with the finding:
"The correlative Raman-SEM/EDX approach shows remarkable potential for the characterization of complex biological tissues and enables the acquisition of complementary information regarding structural complexity, elemental composition and short range chemical bonds. An "all-in-one" Raman-SEM device could therefore make this approach the method of choice for the high-throughput, "synchrotron-free" laboratory-based characterization of biological materials." WITec brought such an integrated device to market in the Fall of 2014; the Raman Imaging and Scanning Electron (RISE) Microscope.
The Silver Paper Award is conferred upon Fernando Rubio-Marcos, Adolfo Del Campo, Pascal Marchet and Jose Fernández from the Institute of Ceramics (Madrid, Spain). They analyzed barium titanate (BaTiO3), a ferroelectric material widely used in electroceramics, and found to their surprise that the domain walls of the material can be altered by polarized light. The effect was verified through Raman microscopy. The researchers believe that this light-stimulated behavior can lead to technological applications such as the development of data storage that can be read without contact, or remotely-controlled piezo-actuators.
The Bronze WITec Paper Award goes to the working group of Jeongyong Kim of Sungkyunkwan University (South Korea) for the detection of minuscule defects in single layers of molybdenum disulfide (MoS2) using confocal Raman microscopy, high-resolution Scanning Near-field Optical Microscopy (SNOM) and electron microscopy. These defects were able to be sought out primarily by virtue of their photoluminescence (PL). The smallest structural defects however, those of only 20 nanometers, could not be investigated with a conventional confocal Raman microscope. For these measurements a WITec SNOM was required, with which high-resolution optical and Raman images could be recorded simultaneously. Thin MoS2 is a so-called two-dimensional material with the properties of a semiconductor. As the optical and electrical properties of semiconductors are strongly affected by defects and grain boundaries, their detection is of great importance.
Admir Masic and James Weaver: Large area sub-micron chemical imaging of magnesium in sea urchin teeth. J. Struct. Biol. 2015, 189: 269.
Fernando Rubio-Marcos, Adolfo Del Campo, Pascal Marchet and Jose F. Fernández: Ferrolectric domain wall motion induced by polarized light. Nature Communications 2015, 6: 6594.
Yongjun Lee, Seki park, Hyun Kim, Gang Hee Han, Young Hee Lee and Jeongyong Kim: Characterization of the structural defects in CVD-grown monolayered MoS2 using near-field photoluminescence imaging. Nanoscale 2015, 7: 11909