2 research outputs found
Radial Growth of Self-Catalyzed GaAs Nanowires and the Evolution of the Liquid Ga-Droplet Studied by Time-Resolved in Situ Xāray Diffraction
We report on a growth
study of
self-catalyzed GaAs nanowires based on time-resolved in situ X-ray
structure characterization during molecular-beam-epitaxy in combination
with ex situ scanning-electron-microscopy. We reveal the evolution
of nanowire radius and polytypism and distinguish radial growth processes
responsible for tapering and side-wall growth. We interpret our results
using a model for diameter self-stabilization processes during growth
of self-catalyzed GaAs nanowires including the shape of the liquid
Ga-droplet and its evolution during growth
Adsorption and Inactivation of SARS-CoVā2 on the Surface of Anatase TiO<sub>2</sub>(101)
We investigated the adsorption of
severe acute respiratory syndrome
corona virus 2 (SARS-CoV-2), the virus responsible for the current
pandemic, on the surface of the model catalyst TiO2(101)
using atomic force microscopy, transmission electron microscopy, fluorescence
microscopy, and X-ray photoelectron spectroscopy, accompanied by density
functional theory calculations. Three different methods were employed
to inactivate the virus after it was loaded on the surface of TiO2(101): (i) ethanol, (ii) thermal, and (iii) UV treatments.
Microscopic studies demonstrate that the denatured spike proteins
and other proteins in the virus structure readsorb on the surface
of TiO2 under thermal and UV treatments. The interaction
of the virus with the surface of TiO2 was different for
the thermally and UV treated samples compared to the sample inactivated
via ethanol treatment. AFM and TEM results on the UV-treated sample
suggested that the adsorbed viral particles undergo damage and photocatalytic
oxidation at the surface of TiO2(101) which can affect
the structural proteins of SARS-CoV-2 and denature the spike proteins
in 30 min. The role of Pd nanoparticles (NPs) was investigated in
the interaction between SARS-CoV-2 and TiO2(101). The presence
of Pd NPs enhanced the adsorption of the virus due to the possible
interaction of the spike protein with the NPs. This study is the first
investigation of the interaction of SARS-CoV-2 with the surface of
single crystalline TiO2(101) as a potential candidate for
virus deactivation applications. Clarification of the interaction
of the virus with the surface of semiconductor oxides will aid in
obtaining a deeper understanding of the chemical processes involved
in photoinactivation of microorganisms, which is important for the
design of effective photocatalysts for air purification and self-cleaning
materials