Sub-nanometer resolution XPS depth profiling: Sensing of atoms

Escherichia coli Colonization of Intestinal Epithelial Layers In Vitro in the Presence of Encapsulated Bifidobacterium breve for Its Protection against Gastrointestinal Fluids and Antibiotics

“…Yolk–shell encapsulation through SiO 2 nanoparticle assembly reduced elemental surface concentrations of carbon, nitrogen, and phosphorus (Table ), while oxygen and silicon appeared in a ratio of 2.1. This ratio confirms full encapsulation of bacteria with SiO 2 nanoparticles with a thickness that, in a freeze-dried state, exceeds the XPS depth of information, that is, around 5 nm . The presence of SiO 2 nanoparticles was furthermore confirmed by decomposition of the O 1s electron binding energy spectrum (Figure S2B), demonstrating Si–O as the major component in the shell.…”

“…This ratio confirms full encapsulation of bacteria with SiO 2 nanoparticles with a thickness that, in a freeze-dried state, exceeds the XPS depth of information, that is, around 5 nm. 34 The presence of SiO 2 nanoparticles was furthermore confirmed by decomposition of the O 1s electron binding energy spectrum (Figure S2B), demonstrating Si−O as the major component in the shell. Alginate hydrogel encapsulation also reduced nitrogen counts (Table 1), but O 1s peak components representative of cell surface proteins remained detectable (Figure S2C), probably because the hydrogel shell collapsed into a thin layer upon freeze-drying as required for XPS analysis.…”

Application of X-ray photoelectron spectroscopy (XPS) and a functional near infrared spectroscopy (fNIRS) in medicine

“…The high accuracy of determining the energy of currently produced XPS spectrometers allows, with the help of an appropriate software, to determine even the position of atoms in the Z direction (vertically to the surface of the sample) [10]. In Fig 3 . the spectrum in the Z axis direction is shown for the mono layer of the self-organizing film (SAM) containing iron and nitrogen.…”

Depth profiling of noble gas atoms implanted in Al matrix: A photoelectron energy loss spectroscopy study

“…intensities in angle resolved XPS measurements, however additional stoichiometric constraints are critical for successful recovery of relative concentration profiles [27,28]. On the other hand, the intensity of the surface and bulk plasmon excitations has been used as a signature of microstructure and material growth mechanisms [29].…”