Molar concentration from sequential 2-D water-window X-ray ptychography and X-ray fluorescence in hydrated cells

Abstract

Recent developments in biological X-ray microscopy have allowed structural information and elemental distribution to be simultaneously obtained by combining X-ray ptychography and X-ray fluorescence microscopy. Experimentally, these methods can be performed simultaneously; however, the optimal conditions for each measurement may not be compatible. Here, we combine two distinct measurements of ultrastructure and elemental distribution, with each measurement performed under optimised conditions. By combining optimised ptychography and fluorescence information we are able to determine molar concentrations from two-dimensional images, allowing an investigation into the interactions between the environment sensing filopodia in fibroblasts and extracellular calcium. Furthermore, the biological ptychography results we present illustrate a point of maturity where the technique can be applied to solve significant problems in structural biology.

Attosecond Pulse Amplification in a Plasma-Based X-Ray Laser Dressed by an Infrared Laser Field

“…Ultrashort coherent X-ray pulses provide a unique combination of record-high spatial and temporal resolution, which finds numerous applications, ranging from dynamical imaging of nanostructured materials and controlling chemical reactions to manipulation of absorption and ionization properties of atoms on a sub-fs time scale [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. One of the most promising applications of such pulses is an ultrafast imaging of large biological molecules, in particular, proteins.…”

Frontier methods in coherent X-ray diffraction for high-resolution structure determination

“…The resultant images allowed the localization of nanoparticle clusters, although individual nanoparticles could not be revealed due to the modest resolution of 250 nm (Maiden et al 2013). This has been taken one step further with fully hydrated, but fixed cells being imaged within the water window by ptychography (Jones et al 2016). Careful characterization of the cellular mass density of mouse embryonic fibroblasts (MEF) through a combination of ptychography and X-ray fluorescence experiments allowed quantitative determination of the molar concentration of several elements within different sub-cellular compartments.…”

Correlative cellular ptychography with functionalized nanoparticles at the Fe L-edge

“…One method ideally suited to probe individual nanoparticles inside cells is coherent diffractive imaging (CDI) since it can image thick specimens with high resolution and contrast [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] . Since the first experimental demonstration in 1999 5 , various CDI methods have been developed 24 and a particularly powerful approach for imaging extended objects such as whole cells is ptychographic CDI (also known as ptychography) [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] . In ptychography, an extended sample is observed by illuminating with a coherent wave via a 2D raster scan.…”

“…During such a 2D scan, diffraction patterns are recorded from overlapping fields of views with a pre-defined trajectory. The overlap between views can then be used as a strong constraint in phase retrieval algorithms 29 , leading to a unique, robust reconstruction of the complex exit wave of the object and the illumination function 26,[30][31][32][33][34][35][36][37][38][39][40][41] . Furthermore, by measuring diffraction intensity with a numerical aperture significantly higher than that of X-ray lenses, ptychography can reach spatial resolutions far beyond those of conventional X-ray microscopy.…”