Urinary‐based infections affect millions of people worldwide. Such bacterial infections are mainly caused by Escherichia coli (E. coli) biofilm formation in the bladder and/or urinary catheters. Herein, the authors present a hybrid enzyme/photocatalytic microrobot, based on urease‐immobilized TiO2/CdS nanotube bundles, that can swim in urea as a biocompatible fuel and respond to visible light. Upon illumination for 2 h, these microrobots are able to remove almost 90% of bacterial biofilm, due to the generation of reactive radicals, while bare TiO2/CdS photocatalysts (non‐motile) or urease‐coated microrobots in the dark do not show any toxic effect. These results indicate a synergistic effect between the self‐propulsion provided by the enzyme and the photocatalytic activity induced under light stimuli. This work provides a photo‐biocatalytic approach for the design of efficient light‐driven microrobots with promising applications in microbiology and biomedicine.
Achieving fast ionic conductivity in the electrolyte
at low operating
temperatures while maintaining the stable and high electrochemical
performance of solid oxide fuel cells (SOFCs) is challenging. Herein,
we propose a new type of electrolyte based on perovskite Sr0.5Pr0.5Fe0.4Ti0.6O3−δ for low-temperature SOFCs. The ionic conducting behavior of the
electrolyte is modulated using Mg doping, and three different Sr0.5Pr0.5Fe0.4–x
Mg
x
Ti0.6O3−δ (x = 0, 0.1, and 0.2) samples are prepared. The
synthesized Sr0.5Pr0.5Fe0.2Mg0.2Ti0.6O3−δ (SPFMg0.2T) proved to be an optimal electrolyte material, exhibiting
a high ionic conductivity of 0.133 S cm–1 along
with an attractive fuel cell performance of 0.83 W cm–2 at 520 °C. We proved that a proper amount of Mg doping (20%)
contributes to the creation of an adequate number of oxygen vacancies,
which facilitates the fast transport of the oxide ions. Considering
its rapid oxide ion transport, the prepared SPFMg0.2T presented
heterostructure characteristics in the form of an insulating core
and superionic conduction via surface layers. In addition, the effect
of Mg doping is intensively investigated to tune the band structure
for the transport of charged species. Meanwhile, the concept of energy
band alignment is employed to interpret the working principle of the
proposed electrolyte. Moreover, the density functional theory is utilized
to determine the perovskite structures of SrTiO3−δ and Sr0.5Pr0.5Fe0.4–x
Mg
x
Ti0.6O3−δ (x = 0, 0.1, and 0.2) and their electronic states.
Further, the SPFMg0.2T with 20% Mg doping exhibited low
dissociation energy, which ensures the fast and high ionic conduction
in the electrolyte. Inclusively, Sr0.5Pr0.5Fe0.4Ti0.6O3−δ is a promising
electrolyte for SOFCs, and its performance can be efficiently boosted
via Mg doping to modulate the energy band structure.
Carbon-based nanomaterials (C-BNM) have recently attracted an increased attention as the materials with potential applications in industry and medicine. Bioresistance and proinflammatory potential of C-BNM is the main obstacle for their medicinal application which was documented in vivo and in vitro. However, there are still limited data especially on graphene derivatives such as graphene platelets (GP). In this work, we compared multi-walled carbon nanotubes (MWCNT) and two different types of pristine GP in their potential to activate inflammasome NLRP3 (The nod-like receptor family pyrin domain containing 3) in vitro. Our study is focused on exposure of THP-1/THP1-null cells and peripheral blood monocytes to C-BNM as representative models of canonical and alternative pathways, respectively. Although all nanomaterials were extensively accumulated in the cytoplasm, increasing doses of all C-BNM did not lead to cell death. We observed direct activation of NLRP3 via destabilization of lysosomes and release of cathepsin B into cytoplasm only in the case of MWCNTs. Direct activation of NLRP3 by both GP was statistically insignificant but could be induced by synergic action with muramyl dipeptide (MDP), as a representative molecule of the family of pathogen-associated molecular patterns (PAMPs). This study demonstrates a possible proinflammatory potential of GP and MWCNT acting through NLRP3 activation.
The present work exploits Ti sheets and TiO 2 nanotube (TNT) layers and their surface modifications for the proliferation of different cells. Ti sheets with a native oxide layer, Ti sheets with a crystalline thermal oxide layer, and two kinds of TNT layers (prepared via electrochemical anodization) with a defined inner diameter of 12 and 15 nm were used as substrates. A part of the Ti sheets and the TNT layers was additionally coated by thin TiO 2 coatings using atomic layer deposition (ALD). An increase in cell growth of WI-38 fibroblasts (>50%), MG-63 osteoblasts (>30%), and SH-SY5Y neuroblasts (>30%) was observed for all materials coated by five cycles ALD compared to their uncoated counterparts. The additional ALD TiO 2 coatings changed the surface composition of all materials but preserved their original structure and protected them from unwanted crystallization and shape changes. The presented approach of mild surface modification by ALD has a significant effect on the materials' biocompatibility and is promising toward application in implant materials.
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