Boron-Doped Dinickel Phosphide to Enhance Polysulfide Conversion and Suppress Shuttling in Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries are promising for next-generation high-energy energy storage systems. However, the slow reaction kinetics render mobile polysulfides hardly controlled, yielding shuttling effects and eventually damaging Li metal anodes. To improve the cyclability of Li-S batteries, high-efficiency catalysts are desired to accelerate polysulfide conversion and suppress the shuttling effect. Herein, we studied a doping system with Ni2P and Ni2B as the end members and found a B-doped Ni2P catalyst that demonstrates high activity for Li-S batteries. As anionic dopants, B demonstrates an interesting reverse electron transfer to P and tunes the electronic structure of Ni2P dramatically. The resultant B-doped Ni2P exhibits short Ni-B bonds and strong Ni-S interaction, and the electron donation of B to P further enhances the adsorption of polysulfide on catalysts. The S-S bonds of polysulfides were activated appropriately, therefore decreasing a low energy barrier for conversion reactions.

Rapid dissolution microneedle based on polyvinyl alcohol/chitosan for local oral anesthesia.

At present, the main clinical methods of oral local anesthesia are direct injection of anesthetic and surface ointment. However, the pain and fear caused by the injection, the discomfort of topical anesthetic creams, and the scour and moist oral environment during the procedure pose great challenges to oral anesthesia. Herein, we designed a Lido-PVP/PVA DMNP microneedle (MN) for oral local anesthesia. The microneedle tip was consisted of Polyvinylpyrrolidone/Polyvinyl alcohol (PVP/PVA), which can quickly dissolve and release the lidocaine hydrochloride (Lido) drug within 5 min to achieve rapid anesthesia. The backing was composed of polyvinyl alcohol/chitosan (PVA/CS), and its excellent adhesion can overcome saliva erosion and anchor firmly to the oral mucosa, significantly improving the utilization rate of drugs, as well as the patient compliance. MNs have good mechanical properties for tissue insertion while possessing high drug loading (3 mg/MNs). Von Frey tests proved that MNs showed a faster and more effective local anesthetic effect (anesthesia takes effect at 5 min) compared to cream (anesthesia takes effect at 30 min). In addition, the excellent biocompatibility and no skin irritation endowed Lido-PVP/PVA DMNP MNs a great potential for oral local anesthesia in the oral cavity.

Vanadium Intercalation into Niobium Disulfide to Enhance the Catalytic Activity for Lithium-Sulfur Batteries.

Despite their high specific energy and great promise for next-generation energy storage, lithium-sulfur (Li-S) batteries suffer from polysulfide shuttling, slow redox kinetics, and poor cyclability. Catalysts are needed to accelerate polysulfide conversion and suppress the shuttling effect. However, a lack of structure-activity relationships hinders the rational development of efficient catalysts. Herein, we studied the Nb-V-S system and proposed a V-intercalated NbS2 (Nb3VS6) catalyst for high-efficiency Li-S batteries. Structural analysis and modeling revealed that undercoordinated sulfur anions of [VS6] octahedra on the surface of Nb3VS6 may break the catalytic inertness of the basal planes, which are usually the primary exposed surfaces of many 2D layered disulfides. Using Nb3VS6 as the catalyst, the resultant Li-S batteries delivered high capacities of 1541 mAh g-1 at 0.1 C and 1037 mAh g-1 at 2 C and could retain 73.2% of the initial capacity after 1000 cycles. Such an intercalation-induced high activity offers an alternative approach to building better Li-S catalysts.

Polytonic Drug Release via Multi-Hierarchical Microstructures Enabled by Nano-Metamaterials.

″Nano-metamaterials″, rationally designed novel class metamaterials with multilevel microarchitectures and both characteristic sizes and whole sizes at the nanoscale, are introduced into the area of drug delivery system (DDS), and the relationship between release profile and treatment efficacy at the single-cell level is revealed for the first time. Fe3+ -core-shell-corona nano-metamaterials (Fe3+ -CSCs) are synthesized using a dual-kinetic control strategy. The hierarchical structure of Fe3+ -CSCs, with a homogeneous interior core, an onion-like shell, and a hierarchically porous corona. A novel polytonic drug release profile occurred, which consists of three sequential stages: burst release, metronomic release, and sustained release. The Fe3+ -CSCs results in overwhelming accumulation of lipid reactive oxygen species (ROS), cytoplasm ROS, and mitochondrial ROS in tumor cells and induces unregulated cell death. This cell death modality causes cell membranes to form blebs, seriously corrupting cell membranes to significantly overcome the drug-resistance issues. It is first demonstrated that nano-metamaterials of well-defined microstructures can modulate drug release profile at the single cell level, which in turn alters the downstream biochemical reactions and subsequent cell death modalities. This concept has significant implications in the drug delivery area and can serve to assist in designing potential intelligent nanostructures for novel molecular-based diagnostics and therapeutics.

Dopamine and DNA functionalized manganese whitlockite nanocrystals for magnetic resonance imaging and chemo-photothermal therapy of tumors.

Multifunctional inorganic nanomaterials have opened new avenues for cancer diagnosis and therapy. However, the difficulty to functionalize them has prevented their wider application, owing to the lack of active groups on their surfaces. Here we report a novel method to functionalize manganese whitlockite (Mn-WH) with polydopamine (PDA) and hairpin DNA (hpDNA) to improve the water stability and anti-cancer effects of Mn-WH nanoparticles (Mn-WH NPs). Compared to WH NPs, the Mn-WH@PDA-hpDNA NPs exhibit better water dispersibility, high drug loading capacity, excellent photothermal performance, stable MRI imaging ability, and outstanding chemo-photothermal synergistic therapeutic potential against tumors. After intratumoral injection in nude mice, the Mn-WH@PDA-hpDNA-DOX NPs promote complete tumor ablation upon exposure to 808 laser-irradiation. The nanoparticles showed no major side effects or toxicity. Thus, these results indicate that the Mn-WH@PDA-hpDNA-DOX NPs have excellent potential as anti-cancer agents, along with excellent magnetic resonance imaging (MRI) capabilities and the reported functionalization approach provides a novel and effective strategy for the surface functionalization of inorganic nanomaterials.

Tuning the Local Coordination of CoP1-xSx between NiAs- and MnP-Type Structures to Catalyze Lithium-Sulfur Batteries.

The slow conversion and rapid shuttling of polysulfides remain major challenges that hinder the practical application of lithium-sulfur (Li-S) batteries. Efficient catalysts are needed to accelerate the conversion and suppress the shuttling. However, the lack of a rational understanding of catalysis poses obstacles to the design of catalysts, thereby limiting the rapid development of Li-S batteries. Herein, we theoretically analyze the modulation of the electronic structure of CoP1-xSx caused by the NiAs-to-MnP-type transition and its influence on catalytic activity. We found that the interacting d-orbitals of the active metal sites play a determining role in adsorption and catalysis, and the optimal dz2-, dxz-, and dyz-orbitals in an appropriately distorted five-coordinate pyramid enable higher catalytic activity compared with their parent structures. Finally, rationally designed catalysts and S were electrospun into carbonized nanofibers to form nanoreactor chains for use as cathodes. The resultant Li-S batteries exhibited superior properties over 1000 cycles with only a decay rate of 0.031% per cycle and demonstrated a high capacity of 887.4 mAh g-1 at a high S loading of 10 mg cm-2. The structural modulation and bonding analyses in this study provide a powerful approach for the rational design of Li-S catalysts.

A Dual-Kinetic Control Strategy for Designing Nano-Metamaterials: Novel Class of Metamaterials with Both Characteristic and Whole Sizes of Nanoscale.

Increasingly intricate in their multilevel multiscale microarchitecture, metamaterials with unique physical properties are challenging the inherent constraints of natural materials. Their applicability in the nanomedicine field still suffers because nanomedicine requires a maximum size of tens to hundreds of nanometers; however, this size scale has not been achieved in metamaterials. Therefore, "nano-metamaterials," a novel class of metamaterials, are introduced, which are rationally designed materials with multilevel microarchitectures and both characteristic sizes and whole sizes at the nanoscale, investing in themselves remarkably unique and significantly enhanced material properties as compared with conventional nanomaterials. Microarchitectural regulation through conventional thermodynamic strategy is limited since the thermodynamic process relies on the frequency-dependent effective temperature, Teff (ω), which limits the architectural regulation freedom degree. Here, a novel dual-kinetic control strategy is designed to fabricate nano-metamaterials by freezing a high-free energy state in a Teff (ω)-constant system, where two independent dynamic processes, non-solvent induced block copolymer (BCP) self-assembly and osmotically driven self-emulsification, are regulated simultaneously. Fe3+ -"onion-like core@porous corona" (Fe3+ -OCPCs) nanoparticles (the products) have not only architectural complexity, porous corona and an onion-like core but also compositional complexity, Fe3+ chelating BCP assemblies. Furthermore, by using Fe3+ -OCPCs as a model material, a microstructure-biological performance relationship is manifested in nano-metamaterials.

Regulated Electrodeposition of Na Metal in Monolithic ZIF-Pillared Graphene Anodes.

Sodium (Na) metal batteries receive increasing attention because of their high energy densities and low costs that are enabled by the abundant Na resources. However, dendritic growth and low efficiency of Na-metal anodes limit the practical applications of Na-metal batteries. Here, we propose a three-dimensionally pillared structure in which carbonized nanoparticles of zeolite imidazolate framework-8 (ZIF-8) are sandwiched between reduced graphene oxide (rGO) sheets (ZIF-8-C@rGO). Such a pillared structure enables two advantages over rGO. First, the sodiation products of ZIF-8 (NaZn13, Na2O, and N-doped carbon) have a strong chemical affinity to Na metal, thereby inducing favorable nucleation of Na metal to guide Na deposition. Second, the pillared structure could facilitate the diffusion of Na ions through rGO sheets and help homogenize the current distribution, leading to a uniform deposition of Na metal. As a result, ZIF-8-C@rGO exhibits a dendrite-free morphology during Na plating/stripping and excellent cycling stability with high Coulombic efficiency of over 99.8% for at least 2000 h. A symmetric cell could maintain more than 4000 h with a stable average overpotential of only 30 mV at a capacity of 1 mA h cm-2. This work demonstrates that the design of a ZIF-pillared structure could combine thermodynamic and kinetic regulating factors to offer an alternative solution to the development of durable Na electrodes for high-performance Na-metal batteries.

Bioremediation of oily sludge by solid complex bacterial agent with a combined two-step process.

In the present research, a bioremediation process was developed using solid complex bacterial agents (SCBA) through a combined two-step biodegradation process. Four isolated strains showed high efficiency for the degradation of total petroleum hydrocarbons (TPH) and the reduction of COD of the oily sludge, at 96.6% and 92.6%, respectively. The mixed strains together with bran prepared in form of SCBA exhibited improved performance compared to individual strains, all of which had an optimal temperature of around 35 °C. The use of SCBA provided advantages over commonly used liquid media for storage and transportation. The two-step process, consisting of firstly biosurfactant-assisted oil recovery and secondly biodegradation of the remaining TPH with SCBA, demonstrated the capability for treating oily sludge with high TPH content (>10 wt%) and short process period (60 days). The large-scale (5 tons oily sludge) field test, achieving a TPH removal efficiency of 93.8% and COD reduction of 91.5%, respectively, confirmed the feasibility and superiority of the technology for industrial applications.

Eurocristatine, a plant alkaloid from Eurotium cristatum, alleviates insulin resistance in db/db diabetic mice via activation of PI3K/AKT signaling pathway.

Eurocristatine (ECT) is an alkaloid isolated from Eurotium cristatum, and it has been used in multiple applications. However, its use as a treatment for type 2 diabetes mellitus (T2DM) has not yet been reported. In this study, we investigated the anti-T2DM effect of ECT and explored its potential molecular mechanism. In vivo, after treatment with ECT (20, 40 mg/kg) for 6 weeks, fasting blood glucose (FBG) was remarkably reduced in db/db mice. Moreover, glucose tolerance, insulin sensitivity and hyperinsulinemia were ameliorated treatment with ECT. The values of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) also showed that ECT could alleviate liver toxicity caused by diabetes in db/db mice. In vitro, ECT (15 and 30 µM) alleviated insulin resistance by increasing glucose consumption, glucose uptake and glycogen content in high glucose-induced HepG2 cells. The Western blotting (WB) results showed that ECT could upregulate the expression of phosphatidylinositol 3-kinase (PI3K), increase the phosphorylation of insulin receptor substrate 1 (IRS1) and protein kinase B (AKT) in vivo and in vitro. Besides, ECT improved the glycogen content by inhibiting the expression of glycogen synthase kinase3ß (GSK3ß) and promoting that of glycogen synthase (GS). Furthermore, administration of the PI3K/AKT signaling pathway inhibitor LY294002 abolished the beneficial effects of ECT. These findings are the first to verify that ECT has the potential to improve glucose metabolism and alleviate insulin resistance by activating the PI3K/AKT signaling pathway in db/db mice.

Preparation of Injectable Composite Hydrogels by Blending Poloxamers with Calcium Carbonate-Crosslinked Sodium Alginate.

The effects of calcium carbonate-crosslinked sodium alginate on poloxamer hydrogels have been investigated. The mechanical strength, degradability, and thermal stability of hydrogels were characterized. The chemical and physical crosslinking in the composite hydrogels has resulted in an improvement of the compressive strength and elasticity of the hydrogels. These mixed hydrogels showed improved mechanical properties, elasticity, and stability as well as environmental responsiveness and injectability.

A novel bovine serum albumin and sodium alginate hydrogel scaffold doped with hydroxyapatite nanowires for cartilage defects repair.

Cartilage tissue engineering has become the trend of cartilage defect repair owing to the engineered biomimetic tissue that can mimic the structural, biological and functional characteristics of natural cartilage. Biomaterials with high biocompatibility and regeneration capacity are expected to be used in cartilage tissue engineering. Herein, in this study, a dual-network bovine serum albumin/sodium alginate with hydroxyapatite nanowires composite (B-S-H) hydrogel scaffold has been prepared for cartilage repair. The obtained B-S-H hydrogel scaffold exhibits ideal physical properties, such as excellent mechanical strength, high porosity and swelling ratio, as well as the excellent biological activity to promote the human bone marrow derived mesenchymal stem cells (hBMSCs) proliferation and differentiation. The in vivo study further shows that the B-S -H hydrogel scaffold can obviously promote the generation of new cartilage that integrates well with surrounding tissues and is similar to adjacent cartilage in terms of thickness. It is considered that the B-S-H hydrogel scaffold has great potential in the application of cartilage defects repair.

Ginsenoside Rg5/Rk1 ameliorated sleep via regulating the GABAergic/serotoninergic signaling pathway in a rodent model.

As the most common sleep disorder, insomnia seriously affects people's everyday lives. Phytochemicals have been shown to have excellent sleep-promoting effects. Therefore, this study was designed to investigate whether Rg5 and Rk1 extracted from ginseng had sleep-promoting effects and to explore their potential mechanisms. The results showed that Rg5 and Rk1 could significantly lessen the locomotor activity of mice and promote the sleep quality index, including increasing the amount of sleep in a pentobarbital sodium experiment with a threshold dose. In parallel, Rg5 and Rk1 could significantly shorten the sleep latency of mice and prolong the sleep time of mice. Furthermore, Rg5 and Rk1 augmented the GABA/Glu ratio, up-regulating the expression of the GABAA receptor and the GABAB receptor, whereas the GABAA receptor antagonist picrotoxin could antagonize the sleep quality of Rg5/Rk1. In addition, 5-HTP, the precursor of 5-HT, could enhance the sleep effect of Rg5 and Rk1 in mice, and both Rg5 and Rk1 could up-regulate the expression of 5-HT1A. These results were also confirmed by the detection of GABA and 5-HT in mouse cecum content. In conclusion, ginsenoside Rg5/Rk1 can exert sedative and hypnotic effects by affecting the GABA nervous system and the serotonin nervous system.

Newly Designed Human-Like Collagen to Maximize Sensitive Release of BMP-2 for Remarkable Repairing of Bone Defects.

Designing the "ideal" hydrogel/matrix which can load bone morphogenetic protein-2 (BMP-2) in a low dose and with a sustained release is the key for its successful therapeutic application to enhance osteogenesis. The current use of natural collagen sponges as hydrogel/matrix is limited due to the collagen matrix showing weak mechanical strength and unmanageable biodegradability. Furthermore, the efficiency and safe dose usage of the BMP-2 has never been seriously considered other than purely chasing the lowest dose usage and extended-release time. In this paper, we customized a novel enzymatically cross-linked recombinant human-like collagen (HLC) sponge with low immunogenicity, little risk from hidden viruses, and easy production. We obtained a unique vertical pore structure and the porosity of the HLC, which are beneficial for Mesenchymal stem cells (MSCs) migration into the HLC sponge and angiopoiesis. This HLC sponge loading with low dose BMP-2 (1 µg) possessed high mechanical strength along with a burst and a sustained release profile. These merits overcome previous limitations of HLC in bone repair and are safer and more sensitive than commercial collagens. For the first time, we identified that a 5 µg dose of BMP-2 can bring about the side effect of bone overgrowth through this sensitive delivery system. Osteoinduction of the HLC-BMP sponges was proved by an in vivo mouse ectopic bone model and a rat cranial defect repair model. The method and the HLC-BMP sponge have the potential to release other growth factors and aid other tissue regeneration. Additionally, the ability to mass-produce HLC in our study overcomes the current supply shortage, which limits bone repair in the clinic.

Biodegradation of crude oil by Chelatococcus daeguensis HB-4 and its potential for microbial enhanced oil recovery (MEOR) in heavy oil reservoirs.

Biodegradation of crude heavy oil was investigated with Chelatococcus daeguensis HB-4 that was isolated from the produced fluid of Baolige Oilfield in China. Batch growth characterization and crude oil degradation tests confirmed HB-4 to be facultative anaerobic and able to degrade heavy oil. The oil degradation was found to occur through degrading long hydrocarbons chains to shorter ones, resulting in oil viscosity reduction. By mixing crude oil with glucose, or using sole crude oil as carbon source, the content of light fractions (C8-C22) increased by 4.97% while heavy fractions (C23-C37) decreased by 7.98%. It was also found that bioemulsifiers were produced rather than commonly observed biosurfactants in the fermentation process, which was attributed to the extracellular degradation of hydrocarbons. Core flooding tests demonstrated 20.5% oil recovery by microbial enhancement, and 59.8% viscosity reduction, showing potential of strain HB-4 for application in the oil industry, especially in enhanced heavy oil recovery.

PdO/SnO2 heterostructure for low-temperature detection of CO with fast response and recovery.

In this paper, we developed a simple two-step route to prepare a PdO/SnO2 heterostructure with the diameter of the SnO2 and PdO nanoparticles at about 15 nm and 3 nm, respectively. In the evaluation temperature window between 80 °C and 340 °C, PdO/SnO2 shows the best response to 100 ppm of CO at 100 °C with fast response time (14 s) and recovery time (8 s). Furthermore, the PdO/SnO2 nanoparticles exhibit a low detection limit and good selectivity to CO against interfering gases as well as rarely-seen low-temperature stability and reversibility. Such enhanced gas sensing performance could be attributed to both the ultrafine structure of PdO and the synergy between PdO and SnO2. The results clearly indicate the application of PdO/SnO2 as a pratical low-temperature sensing material for CO.

Ultrafine nanoparticles of W-doped SnO2 for durable H2S sensors with fast response and recovery.

Ultrafine nanoparticles of W-doped SnO2 with an average diameter of 6 nm were fabricated via a facile hydrothermal method. The material shows a reduced particle size and enhanced response to H2S gas as compared to the pristine SnO2 nanoparticles. The detection limit can be down to 100 ppb while the response time and recovery time of the 5%-doped one are reduced to 17 s and 7 s respectively. In addition, the material shows impressive long-term stability of the response through 40 cycles of injection with 10 ppm H2S, which is attractive for designing a durable hydrogen sulfide sensor. The doping of W results in the reduction of size and modification of the electronic band structure of SnO2, which reduces the response time and recovery time and further improves the sensing durability of the materials.

Hollow Ni-CoSe2 Embedded in Nitrogen-Doped Carbon Nanocomposites Derived from Metal-Organic Frameworks for High-Rate Anodes.

Developing high-rate anode materials with large capacity for lithium ion batteries (LIBs) is quite necessary for the booming electric vehicles industry. The utilization of stable and conductive hollow structures for electrode composite materials could make the desired performances possible in the future. Thus, in this study, a hollow structured Ni-CoSe2 embedded in N-doped amorphous carbon nanocomposite (Ni-CoSe2@NC) has been successfully synthesized with metal-organic frameworks (MOFs) as precursors. Such strategy integrates both the merits of the multicomponents and the hollow structure; the latter could facilitate both mass and charge transport, and the former (the N-doped carbon) could not only offer plenty of surface defects, improving the surface capacitive contributions, but also stabilize the electrode structure during the charge/discharge processes. As a result, the metal selenide composite delivers outstanding high-rate properties with good stability as the anode for LIBs. The structure and components design could also be extended to other anode composites in the future.

Surface grafting of rare-earth ions doped hydroxyapatite nanorods (HAp:Ln(Eu/Tb)) with hydrophilic copolymers based on ligand exchange reaction: Biological imaging and cancer treatment.

Rare-earth ions doped hydroxyapatite nanoparticles (HAp:Ln NPs) have demonstrated to be very promising candidates for biological imaging applications owing to their small size and chemical compositions similar to bone. However, these HAp:Ln NPs with controllable size and morphology should be prepared under hydrothermal treatment with hydrophobic molecules as the protective layers. The hydrophobic nature of these luminescent HAp:Ln NPs largely impeded their applications in biomedical fields. In this study, a novel and effective strategy has been developed for the surface modification of HAp:Ln nanorods through the combination of surface ligand exchange reaction and reversible-addition fragmentation chain transfer (RAFT) polymerization using 2-methacryloyloxyethyl phosphorylcholine (MPC) and itaconic acid (IA) as the monomers. Herein, a small molecule adenosine 5'-monophosphate disodium salt (AMP) that contains a phosphate group and two hydroxyl groups was used to displace the hydrophobic oleic acid on pristine HAp NPs through surface ligand exchange reaction owing to its stronger interaction with HAp NPs. On the other hand, the MPC and IA were introduced on HAp NPs through RAFT polymerization after the chain transfer agent was immobilized on the HAp NPs through the esterification reaction. The poly(IA-MPC) could not only endow the high water dispersibility but also be used for loading anticancer agent cisplatin (CDDP) through coordination interaction. To evaluate their potential biomedical applications, the cell uptake behavior, drug loading capacity and release behavior as well as cell viability of HAp:Ln-AMP-poly(IA-MPC) polymeric composites were examined. We demonstrated that the method developed in this work is very effective for introduction of functional polymers onto HAp:Ln nanorods. The HAp:Ln-AMP-poly(IA-MPC) composites are promising for cell imaging and controlled delivery of CDDP.

Multicomponent metal-organic framework derivatives for optimizing the selective catalytic performance of styrene epoxidation reaction.

Multicomponent metal-organic framework (MOF) derivatives have attracted strong interest in energy and environmental fields. However, most of the papers focus on single MOF derivatives; reports on multicomponent MOF derivatives and their catalytic studies are relatively few. Here, we report an easy-to-operate strategy to obtain multicomponent MOF derivatives by treating multicomponent MOFs under a suitable gas atmosphere and at high temperature. We used ZIF-67 as a template to introduce Zn and successfully obtained multicomponent MOFs. After carbonization, the multicomponent MOF derivatives with Co and CoO nanoparticles exhibit higher conversion of styrene (≈99%), higher selectivity (≈70%) and better stability compared to MOFs and single component MOF derivatives.