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SU fabricated the metal nanoshell arrays on the substrates, measured the optical properties, carried out the BSA binding experiment, and drafted the manuscript. NZ participated in the design of the study and helped draft the manuscript. KE and KY conceived of the study, participated in its design and coordination, and helped draft the manuscript. All this website authors read and approved the final manuscript.”
“Background X-ray fluorescence (XRF) is a highly sensitive, non-destructive technique that is able to detect element traces for material elemental analysis. It is now widely used in various fields of science such as material processing [1], cultural patrimony [2], archaeology [3], medical and biology [4], environment [5], etc. Two approaches are possible to increase the XRF lateral resolution for chemical mapping. First, the primary probe diameter can be decreased as the detector click here aperture is increased to keep a significant signal-to-noise ratio. This is the general tendency both for in-lab classical XRF and in synchrotron

environment where 30-nm resolution can be offered on few beamlines (see example in [6]). The second solution consists in keeping the primary beam diameter constant 17-DMAG (Alvespimycin) HCl and decreasing the detector input aperture. In this latter case, it must be approached as much as possible towards the surface to keep a significant XRF signal detection. However, the detector steric hindrance impedes approaching at sub-millimetre distance from the surface without primary beam shadowing. A solution is to use a sharp monocapillary to collect the XRF signal near the surface. The XRF signal is proportional to the primary source brightness and thus, in both modes, the higher is the brightness, the higher the signal-to-noise ratio can be expected. Thanks to the development of new focusing optics like polycapillary lens [7, 8], micro-XRF analysis became possible using laboratory and even portable X-ray sources [9].