Surface Roughness Modulates Diffusion and Fibrillation of Amyloid‑β Peptide

The presence of surfaces influences the kinetics of amyloid-β (Aβ) peptide fibrillation. Although it has been generally recognized that the fibrillation process can be assisted or accelerated by surface chemistry, the impact of surface topography, i.e., roughness, on peptide fibrillation is relatively little understood. Here we study the role of surface roughness on surface-mediated fibrillation using polymer coatings of varying roughness as well as polymer microparticles. Using single-molecule tracking, atomic force microscopy, and the thioflavin T fluorescence technique, we show that a rough surface decelerates the two-dimensional (2D) diffusion of peptides and retards the surface-mediated fibrillation. A higher degree of roughness that presents an obstacle to peptide diffusion is found to inhibit the fibrillation process

Surface Roughness Modulates Diffusion and Fibrillation of Amyloid‑β Peptide

The presence of surfaces influences the kinetics of amyloid-β (Aβ) peptide fibrillation. Although it has been generally recognized that the fibrillation process can be assisted or accelerated by surface chemistry, the impact of surface topography, i.e., roughness, on peptide fibrillation is relatively little understood. Here we study the role of surface roughness on surface-mediated fibrillation using polymer coatings of varying roughness as well as polymer microparticles. Using single-molecule tracking, atomic force microscopy, and the thioflavin T fluorescence technique, we show that a rough surface decelerates the two-dimensional (2D) diffusion of peptides and retards the surface-mediated fibrillation. A higher degree of roughness that presents an obstacle to peptide diffusion is found to inhibit the fibrillation process

Mesoporous Cobalt Molybdenum Nitride: A Highly Active Bifunctional Electrocatalyst and Its Application in Lithium–O₂ Batteries

Bifunctional electrocatalysts for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) play a critical role in fuel cells and metal–air batteries. In this article, mesoporous cobalt molybdenum nitride (Co₃Mo₃N) is prepared using a coprecipitation method followed by ammonia annealing treatment. Much more active sites generated by well designed mesoporous nanostructure and intrinsically electronic configuration lead to excellent electrocatalytic performance for ORR/OER in Li–O₂ cells, delivering considerable specific capacity and alleviating polarization. It is manifested that high charge–discharge efficiency and good cycle stability were obtained in the LiTFSI/TEGDME electrolyte owing to a stable interface between optimized electrolyte and electrode material

Molybdenum Nitride/N-Doped Carbon Nanospheres for Lithium‑O₂ Battery Cathode Electrocatalyst

Molybdenum nitride/N-doped carbon nanospheres (MoN/N–C) are synthesized by hydrothermal method followed by ammonia annealing. The as-prepared MoN/N–C nanospheres manifest considerable electrocatalytic activity toward oxygen reduction reaction in nonaqueous electrolytes because of its nanostructure and the synergetic effect between MoN and N–C. Furthermore, the MoN/N–C nanospheres are explored as cathode catalyst for Li–O₂ batteries with tetra-(ethylene glycol) dimethyl ether as the electrolyte. The assembled batteries deliver alleviated overpotentials and improved battery lifespan, and their excellent performances should be attributed to the unique hierarchical structure and high fraction of surface active sites of cathode catalyst

Surface Roughness Modulates Diffusion and Fibrillation of Amyloid‑β Peptide

The presence of surfaces influences the kinetics of amyloid-β (Aβ) peptide fibrillation. Although it has been generally recognized that the fibrillation process can be assisted or accelerated by surface chemistry, the impact of surface topography, i.e., roughness, on peptide fibrillation is relatively little understood. Here we study the role of surface roughness on surface-mediated fibrillation using polymer coatings of varying roughness as well as polymer microparticles. Using single-molecule tracking, atomic force microscopy, and the thioflavin T fluorescence technique, we show that a rough surface decelerates the two-dimensional (2D) diffusion of peptides and retards the surface-mediated fibrillation. A higher degree of roughness that presents an obstacle to peptide diffusion is found to inhibit the fibrillation process

Surface Roughness Modulates Diffusion and Fibrillation of Amyloid‑β Peptide

The presence of surfaces influences the kinetics of amyloid-β (Aβ) peptide fibrillation. Although it has been generally recognized that the fibrillation process can be assisted or accelerated by surface chemistry, the impact of surface topography, i.e., roughness, on peptide fibrillation is relatively little understood. Here we study the role of surface roughness on surface-mediated fibrillation using polymer coatings of varying roughness as well as polymer microparticles. Using single-molecule tracking, atomic force microscopy, and the thioflavin T fluorescence technique, we show that a rough surface decelerates the two-dimensional (2D) diffusion of peptides and retards the surface-mediated fibrillation. A higher degree of roughness that presents an obstacle to peptide diffusion is found to inhibit the fibrillation process

Synthesis of Nitrogen-Doped MnO/Graphene Nanosheets Hybrid Material for Lithium Ion Batteries

Nitrogen-doped MnO/graphene nanosheets (N-MnO/GNS) hybrid material was synthesized by a simple hydrothermal method followed by ammonia annealing. The samples were systematically investigated by X-ray diffraction analysis, Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and atomic force microscopy. N-doped MnO (N-MnO) nanoparticles were homogenously anchored on the thin layers of N-doped GNS (N-GNS) to form an efficient electronic/ionic mixed conducting network. This nanostructured hybrid exhibited a reversible electrochemical lithium storage capacity as high as 772 mAh g^–1 at 100 mA g^–1 after 90 cycles, and an excellent rate capability of 202 mA h g^–1 at a high current density of 5 A g^–1. It is expected that N-MnO/GNS hybrid could be a promising candidate material as a high capacity anode for lithium ion batteries

Synergistic Construction of Efficient Heterostructure Electrocatalysis for High-Performance Lithium–Sulfur Batteries

Since a sluggish conversion reaction and shuttling of polysulfides have been barriers to high-performance Li–S batteries, it is particularly critical to establish nanostructured electrocatalysts with high specific surface area and electron conductivity, an excellent anchoring capability, and long-term durability. Herein, a robust binary synergistic MoS2/MXene heterostructure is proposed by the homogeneous growth of MoS2 on an MXene substrate. Due to the hierarchical structure and strong interfacial coupling effect, the binary synergistic MoS2/MXene heterostructure not only suppresses the restacking of MoS2 and MXene nanosheets but also provides abundant active sites to capture polysulfides and catalyze its conversion reaction. Typically, polysulfides are immobilized by MoS2 nanosheets; then, the anchored polysulfides are rapidly transferred from MoS2 to MXene via heterointerfaces. The MXene surface is endowed with abundant oxygen terminations, which accelerates the polysulfide conversion kinetics to a great extent. Therefore, the assembled Li–S battery delivers a reversible capacity of 981 mA h g–1 at 0.5 C after 300 cycles. Even at high rate of 5 C, capacity is still maintained at an excellent level of 408 mA h g–1 after 500 cycles with a Coulombic efficiency of 96.5%. Even more fascinating, at 0.2 C, the MoS2/MXene cathode can realize a high sulfur loading of 4.0 mg cm–2 and with capacities of 608 mA h g–1 over 500 cycles, which will promote the practical applications of Li–S batteries