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This paper envisions Ti40Zr10Cu36Pd14 bulk metallic glass as an oral implant material and evaluates its antibacterial performance in the inhabitation of oral biofilm formation in comparison with the gold standard Ti-6Al-4V implant material. Metallic glasses are superior in terms of biocorrosion and have a reduced stress shielding effect compared with their crystalline counterparts. Dynamic mechanical and thermal expansion analyses on Ti40Zr10Cu36Pd14 show that these materials can be thermomechanically shaped into implants. Static water contact angle measurement on samples surface shows an increased surface wettability on the Ti-6Al-4V surface after 48 ​h incubation in the water while the contact angle remains constant for Ti40Zr10Cu36Pd14. Further, high-resolution transmission and scanning transmission electron microscopy analysis have revealed that Ti40Zr10Cu36Pd14 interior is fully amorphous, while a 15 ​nm surface oxide is formed on its surface and assigned as copper oxide. Unlike titanium oxide formed on Ti-6Al-4V, copper oxide is hydrophobic, and its formation reduces surface wettability. Further surface analysis by X-ray photoelectron spectroscopy confirmed the presence of copper oxide on the surface. Metallic glasses cytocompatibility was first demonstrated towards human gingival fibroblasts, and then the antibacterial properties were verified towards the oral pathogen Aggregatibacter actinomycetemcomitans responsible for oral biofilm formation. After 24 ​h of direct infection, metallic glasses reported a >70% reduction of bacteria viability and the number of viable colonies was reduced by ∼8 times, as shown by the colony-forming unit count. Field emission scanning electron microscopy and fluorescent images confirmed the lower surface colonization of metallic glasses in comparison with controls. Finally, oral biofilm obtained from healthy volunteers was cultivated onto specimens surface, and proteomics was applied to study the surface property impact on species composition within the oral plaque.

Transition metal oxides/hydroxides exhibit reasonable oxygen activity in alkaline electrolytes and have been identified as potential electrocatalysts. Some highly active transition metal oxides or hydroxides can alter their surface chemistry in response to the electrolyte environment. This review presents the performance of some of the recently developed transition metal‐based oxides in electrocatalytic oxygen evolution reaction (OER). Despite the promising catalytic activity of many transition metals and their alloys due to their incompletely filled d orbitals, their low corrosion resistance in alkaline media barriers their use as electrocatalysts. Metallic glasses (MGs), with their disordered atomic structure, have many unique and exciting properties that cannot be found in crystalline metals. Metallic glasses′ unique chemical activity and corrosion resistance stem from their metastable and defective nature, as well as their structural and chemical homogeneity. In the case of Zr‐based MGs, the presence of MG−OHads and MG−Ox species on the surface for oxygen evolution enables rapid electron transfer to chemisorbed OH− with an "activated" MG surface leading to the generation of an amorphous Zr‐rich layer. Zr‐rich oxide layer formation favors the OER understood by decreased Tafel slope and highly stable nature during open circuit potential measurements in the alkaline solution. Unlike the as‐spun counterpart, the relatively small impedance magnitude and characteristic frequency for the post‐OER electrode corroborate the enhancement of oxygen evolution kinetics after electrochemistry. Compared with the early discovered electrodes, the MG‐oxide assembly outperforms many transition and precision metal‐based oxides and their composite forms regarding oxygen electroactivity and stability. [ABSTRACT FROM AUTHOR]

Cross-linked polymer composite fibers are gaining more and more interest in the fields of drug delivery, bone regeneration and biomineralization. This study focuses on the replacement of the radical initiator by photoinitiation via benzophenone, resulting in poly(ethylene oxide)-polybutadiene-carbon nanotube (PEO-PBu-CNT) nanofibers. The inclusion of small amounts of CNTs increases the rupture temperature and the first glass transition temperature Tg1 of the composite by 28 and 23 K, respectively, while decreasing the second glass transition temperature Tg2 by 20 K determined by dynamic mechanical analysis. A twice higher initial storage modulus of ~44 MPa can be detected for the CNT-containing samples, indicating the stiffening effect due to CNT addition. Primary X-ray diffraction peaks of PEO shift by 0.42° towards lower angles by the inclusion of CNTs, accounting for the generation of free volume within the polymer composite. Two orders of magnitude increase in Bode magnitude with a rise in Bode angle from 6° to 56° is detected by electrochemical impedance spectroscopy for the UV-cured PEO-PBu-CNT. Entanglement between the fibers, as well as a rough surface with a rigid structure, is observed upon small CNT additions. Finally, attenuated total reflectance--Fourier transform infrared and Raman spectroscopy allow the detection of the main peaks and intensity changes of these polymer composite structures for the UV-cured and uncured states. [ABSTRACT FROM AUTHOR]

Amorphous PdSiAu-based metallic glass thin films (MGTFs) obtained by physical vapor deposition were deposited on multilayered graphene (MLGR) supported on Si/SiO2, where the MLGR is carried to the top by upward pressure of the deposited atomic layer passing through the crystal lattice of graphene. Samples were electrochemically hydrogenated by chronoamperometry and characterized by cyclic voltammetry in 0.1 M H2SO4. MLGR-containing samples have a prominent Raman peak at 1415 cm−1. This sample shows ∼2.6 times larger hydrogen desorption charge and ∼4.5 times larger electrocatalytic hydrogen activity compared to the MLGR-free counterparts. Furthermore, the capacitance retrieved from the simulation of electrochemical impedance data indicates a ∼2.6 times increase upon MLGR inclusion. High-resolution (scanning) transmission electron microscopy after hydrogenation corroborates the existence of nm-sized PdHx crystals around the MGTF–Si/SiO2 interface and the presence of a graphene layer on top of the MGTF due to bond breaking between the MLGR and Si/SiO2. The enhanced hydrogen activity due to the synergistic effect of MLGR and MGTF layer-by-layer nanostructure reveals itself in the diffusion kinetics, where 50% faster hydrogen ion transfer into the MGTF is obtained when the MLGR top layer is present. The areal and volumetric hydrogen desorption charge exceed almost all the considered Pd-based counterparts, especially when comparing systems with similar thicknesses. Hence, the developed hybrid nanostructure can be envisaged as an alternative ultra-high hydrogen charger for small-scale applications. [ABSTRACT FROM AUTHOR]