Renal Clearable Gold Nanoparticle-Functionalized Silk Film for in vivo Fluorescent Temperature Mapping.

Implantable optical sensing devices that can continuously monitor physiological temperature changes hold great potential toward applications in healthcare and medical field. Here, we present a conceptual foundation for the design of biocompatible temperature sensing device by integrating renal clearable luminescent gold nanoparticles (AuNPs) with silk film (AuNPs-SF). We found that the AuNPs display strong temperature dependence in both near-IR fluorescence intensity and lifetime over a large temperature range (10-60°C), with a fluorescence intensity sensitivity of 1.72%/°C and lifetime sensitivity of 0.09 µs/°C. When integrated, the AuNPs with biocompatible silk film are implanted in the dorsal region of mice. The fluorescence imaging of the AuNPs-SF in the body shows a linear relationship between the average fluorescence intensity and temperature. More importantly, <3.68% ID gold are left in the body, and no adverse effect is observed for 8 weeks. This AuNPs-SF can be potentially used as a flexible, biocompatible, and implantable sensing device for in vivo temperature mapping.

Facile in situ fabrication of biomorphic Co2P-Co3O4/rGO/C as an efficient electrocatalyst for the oxygen reduction reaction.

Streptococcus thermophilus, a Gram-positive (G+) bacterium featuring a teichoic acid-rich cell wall, has been employed as both a phosphorus source and template to synthesize a biomorphic Co2P-Co3O4/rGO/C composite as an efficient electrocatalyst for the oxygen reduction reaction (ORR). Different from the conventional method for the synthesis of phosphides, bio-derivative phosphorus vapor was emitted from the inside out, which facilitated the in situ transformation of the chemically adsorbed Co precursor on the bacteria into Co2P-Co3O4 heterogeneous nanoparticles, which featured a Co2P-rich body and Co3O4-rich surface. Besides, reduced graphene oxide (rGO) was also introduced in the synthetic process to keep Co2P-Co3O4 scattered and further promote the electron transport efficiency. All the Co2P-Co3O4 nanoparticles and rGO sheets were supported on the bacteria-derived carbon substrate with submicron-spherical morphology. The as-obtained Co2P-Co3O4/rGO/C composite exhibited excellent electrocatalytic performance for ORR with onset and half-wave potentials of 0.91 and 0.80 V vs. RHE, respectively. Furthermore, its long-term stability and methanol tolerance were better than those of commercial Pt/C. Thus, this work presents a new strategy of using an interior bio-phosphorus source to obtain heterojunction particles featuring a phosphide-rich body and oxide-rich surface, which may provide some insights for the construction of efficient heterogeneous electrocatalysts.

Porous Multicomponent Mn-Sn-Co Oxide Microspheres as Anodes for High-Performance Lithium-Ion Batteries.

Porous multicomponent Mn-Sn-Co oxide microspheres (MnSnO3-MC400 and MnSnO3-MC500) have been fabricated using CoSn(OH)6 nanocubes as templates via controlling pyrolysis of a CoSn(OH)6/Mn0.5Co0.5CO3 precursor at different temperatures in N2. During the pyrolysis process of CoSn(OH)6/Mn0.5Co0.5CO3 from 400 to 500 °C, the part of (Co,Mn)(Co,Mn)2O4 converts into MnCo2O4 accompanied with structural transformation. The MnSnO3-MC400 and MnSnO3-MC500 microspheres as secondary nanomaterials consist of MnSnO3, MnCo2O4, and (Co,Mn)(Co,Mn)2O4. Benefiting from the advantages of multicomponent synergy and porous secondary nanomaterials, the MnSnO3-MC400 and MnSnO3-MC500 microspheres as anodes exhibit the specific capacities of 1030 and 750 mA h g-1 until 1000 cycles at 1 A g-1 without an obvious capacity decay, respectively.

Hierarchical porous MnCo2O4 yolk-shell microspheres from MOFs as secondary nanomaterials for high power lithium ion batteries.

Hierarchical porous MnCo2O4 yolk-shell microspheres have been synthesized via a facile chemical precipitation method with subsequent calcination treatment. The hierarchical porous MnCo2O4 yolk-shell microspheres as secondary nanomaterials can improve the effective contact area between the MnCo2O4 electrode and electrolyte, accommodate the volume variations during cycling, and shorten the Li+ diffusion path in the nanoparticles. Benefiting from their particular structure and interconnected pores, as anodes for lithium ion batteries, the hierarchical porous MnCo2O4 yolk-shell microspheres show high reversible lithium storage capacity, excellent cycling performance and enhanced rate capability. More importantly, they also exhibit long-life and high-rate lithium storage as high as 691.3 mA h g-1 after 500 cycles even at 1 C.

Anchoring MnCo2O4 Nanorods from Bimetal-Organic Framework on rGO for High-Performance Oxygen Evolution and Reduction Reaction.

Oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are important reactions of energy storage and conversion devices. Therefore, it is highly desirable to design efficient and dual electrocatalysts for replacing the traditional noble-metal-based catalysts. Herein, we have developed a high-efficiency and low-cost MnCo2O4-rGO nanocomposite derived from bimetal-organic frameworks. For OER, MnCo2O4-rGO showed an onset potential of 1.56 V (vs reversible hydrogen electrode (RHE)) and a current density of 14.16 mA/cm2 at 1.83 V, being better than both pure MnCo2O4 and Pt/C. For ORR, MnCo2O4-rGO exhibited a half-wave potential (E 1/2) of 0.77 V (vs RHE), a current density of 3.33 mA/cm2 at 0.36 V, a high electron transfer number n (3.80), and long-term stability, being close to the performance of Pt/C. The high activity of MnCo2O4-rGO was attributed to the synergistic effect among rGO, manganese, and cobalt oxide. As a result, the resultant MnCo2O4-rGO has a great potential to be applied as a high-efficiency ORR and OER electrocatalyst.

Influence of fine-grain and solid-solution strengthening on mechanical properties and in vitro degradation of WE43 alloy.

As one of the most important potential candidate alloys for vascular stent application, Mg-Y-Zr based Mg-4.2wt%Y-2.4wt%Nd-0.6wt%Ce(La)-0.5wt%Zr (WE43) alloys were investigated in combination with the forming processes of micro-tubes with 2.0 mm diameter and 0.1 mm wall thickness. Orthogonal experimental design for alloy composition, vacuum melting ingot, heat treatment, integrated plastic deformation and micro-tube forward extrusion are included in the processing procedures. Significant improvements in both the mechanical properties and corrosion resistance in phosphate buffered saline solution for WE43 alloys were achieved through this processing sequence. The influence of the heat treatment and hot extrusion on in vitro degradation and plasticity was found to be associated with grain size reduction and the redistribution of intermetallic particles within the microstructure. As a result, the mechanical properties and the corrosion resistance of Mg alloys can be improved through fine-grain strengthening and solid-solution strengthening to some extent.

Vertically aligned ZnO nanowire arrays tip-grafted with silver nanoparticles for photoelectrochemical applications.

Herein, we demonstrate that uniform Ag nanoparticles could be directionally grafted on the tip of ZnO nanowire arrays by a simple photo-reduction method. Furthermore, the structure, position, and amount of Ag nanoparticles supported on ZnO nanowire arrays could be further rationally tailored by changing the reaction parameters such as the category, concentration of reagents, and annealing temperature. Moreover, their photoelectrochemical performances under both UV-vis and monochromatic light irradiation have been explored. Interestingly, the photocurrent density of Ag-ZnO heterostructures could reach up to 2.40 mA cm(-2), which is much higher than that of pure ZnO nanowire arrays. It has been proposed that the formation of ZnO nanowire arrays tip-grafted with Ag nanoparticles could promote the effective separation and directional transfer of photoexcited electron-hole pairs, and thus enhance the photoconversion properties.