High activity in the dry reforming of methane using a thermally switchable double perovskite and in situ generated molecular level nanocomposite

This work emphasizes the dry reforming of methane (DRM) reaction on citrate sol-gel-synthesized double perovskite oxides. Phase pure La2NiMnO6 shows very impressive DRM activity with H2/CO = 0.9, hence revealing a high prospect of next-generation catalysts. Although the starting double perovskite phase gets degraded into mostly binary oxide phases after a few hours of DRM activity, the activity continues up to 100 h. The regeneration of the original double perovskite out of decomposed phases by annealing at near synthesis temperature, followed by the spectacular retention of activity, is rather interesting and hitherto unreported. This result unravels unique reversible thermal switching between the original double perovskite phase and decomposed phases during DRM without compromising the activity and raises challenge to understand the role of decomposed phases evolved during DRM. We have addressed this unique feature of the catalyst via structure-property relationship using the in situ generated molecular level nanocomposite.

Fabrication of TiO2 microspikes for highly efficient intracellular delivery by pulse laser-assisted photoporation

The introduction of foreign cargo into living cells with high delivery efficiency and cell viability is a challenge in cell biology and biomedical research. Here, we demonstrate a nanosecond pulse laser-activated photoporation for highly efficient intracellular delivery using titanium dioxide (TiO₂) microspikes as a substratum. The TiO₂ microspikes were formed on titanium (Ti) substrate using an electrochemical anodization process. Cells were cultured on top of the TiO₂ microspikes as a monolayer, and the biomolecule was added. Due to pulse laser exposure of the TiO₂ microspike–cell membrane interface, the microspikes heat up and induce cavitation bubbles, which rapidly grow, coalesce and collapse to induce explosion, resulting in very strong fluid flow at the cell membrane surface. Thus, the cell plasma membrane disrupts and creates transient nanopores, allowing delivery of biomolecules into cells by a simple diffusion process. By this technique, we successfully delivered propidium iodide (PI) dye in HeLa cells with high delivery efficiency (93%) and high cell viability (98%) using 7 mJ pulse energy at 650 nm wavelength. Thus, our TiO₂ microspike-based platform is compact, easy to use, and potentially applicable for therapeutic and diagnostic purposes.

The introduction of foreign cargo into living cells with high delivery efficiency and cell viability by laser asisted photoporation on TiO₂ microspikes platform.

Formation of nanostructures on magnesium alloy by anodization for potential biomedical applications

In the present work, we have investigated the formation of nanostructures on AZ31 magnesium alloy using electrochemical anodization technique. The formed nanostructures were efficiently showed bone-like apatite formation followed by its gradual increase, when immersed in simulated body fluid (SBF) and it exhibited controlled degradation in 7 days. Cell viability study was performed using MG-63 cells (human osteosarcoma cell lines) and revealed that the nanostructured surface has excellent biocompatibility by enhancing both cell adhesion and cell growth. The detailed characterization of this anodized surface was evaluated by field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDS). Furthermore, surface-corrosion before and after anodization was examined by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies in SBF. The in-depth studies bring out the fact that native oxide in the sample is converted to a biocompatible nanostructure, which is created due to anodization in a particular electrolyte solution containing ethylene glycol and hybrid hydrofluoric acid mixture.