RESUMO
We used digital in-line soft X-ray holography (DIXH) in the Gabor geometry to image human chromosomes. The divergent wave front was generated by diffraction of synchrotron radiation from a high aspect ratio pinhole. As under our experimental conditions the achievable resolution depends on the pinhole radius, high aspect ratio holes with diameters in the 100 nm range were prepared by focused ion beam (FIB) milling. The central maximum of the obtained Airy pattern was used to image chromosomes prepared from metaphase HeLa cells at experimental resolutions of 370±40 nm with soft X-rays at 260 eV photon energy provided by the BESSY II synchrotron radiation facility.
Assuntos
Holografia/métodos , Microscopia/métodos , Síncrotrons , Cromossomos Humanos/genética , Humanos , Raios XRESUMO
Femtosecond vacuum ultraviolet (VUV) radiation provided by the free-electron laser FLASH was used for digital in-line holographic microscopy and applied to image particles, diatoms and critical point dried fibroblast cells. To realize the classical in-line Gabor geometry, a 1 microm pinhole was used as spatial filter to generate a divergent light cone with excellent pointing stability. At a fundamental wavelength of 8 nm test objects such as particles and diatoms were imaged at a spatial resolution of 620 nm. In order to demonstrate the applicability to biologically relevant systems, critical point dried rat embryonic fibroblast cells were for the first time imaged with free-electron laser radiation.
Assuntos
Elétrons , Holografia/métodos , Lasers , Raios Ultravioleta , Animais , Diatomáceas/citologia , Ratos , Dióxido de Silício , Fatores de Tempo , VácuoRESUMO
Digital in-line soft x-ray holography (DIXH) was used to image immobilized polystyrene and iron oxide particles and to distinguish them based on their different x-ray absorption cross sections in the vicinity of the carbon K-absorption edge. The element-specific information from the resonant DIXH images was correlated with high-resolution scanning electron microscopy (SEM) pictures. We also present DIXH images of a cell nucleus and compare the contrast obtained for nuclear components with the appearance in optical microscopy.
