Fluorimetric determination of histidine by exploiting its inhibitory effect on the oxidation of thiamine by cobalt-containing Prussian Blue nanocubes.

A fluorometric assay for histidine (His) is described. It is based on the inhibitory effect of His on nanocubes consisting of cobalt-containing Prussian Blue analog (CoFe NCbs), which have a strong oxidation effect on thiamine (THI) in the presence of NaOH. THI is nonfluorescent but the oxidized form (thiochrome; ThC) has a strong blue fluorescence, with excitation/emission maxima at 370/445 nm. His inhibits the oxidation effect of the CoFe NCbs due to the strong interaction between its imidazole side chain and the amino groups of the CoFe NCbs. This method is fast and has good sensitivity and selectivity. The lower detection limit is 14.3 nM of His, the linear range extends from 0.05 to 2.5 µM, and the relative standard deviation is calculated to be 1.5%. The method was successfully employed to quantify His in spiked serum samples. Graphical abstractSchematic representation of cobalt-containing Prussian Blue nanocubes (CoFe NCbs)-thiamine (THI)-based fluorometric assay for Histine (His). His inhibits the generation of thiochrome (ThC; the oxidized form of THI). The detection limit is 14.3 nM with the linear range of 0.05-2.5 µM.

Challenges and advances for glioma therapy based on inorganic nanoparticles.

Glioma is one of the most serious central nervous system diseases, with high mortality and poor prognosis. Despite the continuous development of existing treatment methods, the median survival time of glioma patients is still only 15 months. The main treatment difficulties are the invasive growth of glioma and the obstruction of the blood-brain barrier (BBB) to drugs. With rapid advancements in nanotechnology, inorganic nanoparticles (INPs) have shown favourable application prospects in the diagnosis and treatment of glioma. Due to their extraordinary intrinsic features, INPs can be easily fabricated, while doping with other elements and surface modification by biological ligands can be used to enhance BBB penetration, targeted delivery and biocompatibility. Guided glioma theranostics with INPs can improve and enhance the efficacy of traditional methods such as chemotherapy, radiotherapy and gene therapy. New strategies, such as immunotherapy, photothermal and photodynamic therapy, magnetic hyperthermia therapy, and multifunctional inorganic nanoplatforms, have also been facilitated by INPs. This review emphasizes the current state of research and clinical applications of INPs, including glioma targeting and BBB penetration enhancement methods, in vivo and in vitro biocompatibility, and diagnostic and treatment strategies. As such, it provides insights for the development of novel glioma treatment strategies.

Drug in Therapeutic Polymer: Sinomenine-Loaded Oxidation-Responsive Polymeric Nanoparticles for Rheumatoid Arthritis Treatment.

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease that frequently involves cartilage damage and the destruction of the bone structure, ultimately resulting in disability and long-term pain. It is clear that overexpression of reactive oxygen species (ROS) and the complex inflammatory microenvironment are the main causes of RA pathogenesis; thereby, the efficacy of any single-drug treatment is limited. Herein, we formulated a therapeutic hyaluronic acid derivative (PAM-HA) with adsorption capacity to the subchondral bone, a long retention time within inflamed joints, and ROS-scavenging capacity, which was used as a drug carrier for realizing the controlled release of sinomenine (Sin) within arthritic joints. This "drug in therapeutic polymer" design strategy was aimed at realizing antioxidant and anti-inflammatory combination therapy for RA. In vivo experiments suggest that PAM-HA@Sin NPs can be retained in the inflamed joints of rats for a long time compared with commercially available free Sin injections. As expected, therapeutic PAM-HA polymeric carriers can increase joint lubrication and reduce oxidative stress, while the released Sin induces downregulation of proinflammatory factors (TNF-α and IL-1ß) and upregulation of anti-inflammatory factors (Arg-1 and IL-10) via the NF-κB pathway. In summary, a ROS-scavenging hyaluronic acid (HA) derivative was developed as the nanocarrier for Sin delivery to simultaneously remodel the oxidative/inflammatory microenvironment in RA, which opens up new horizons for the development of therapeutic polymers and the combined therapeutic strategies.

In situ synthesis of nitrogen site activated cobalt sulfide@N, S dual-doped carbon composite for a high-performance asymmetric supercapacitor.

Cobalt sulfides with high theoretical capacity are considered as potential electrodes for supercapacitors (SCs). However, the insufficient reactive sites and low electrical conductivity of bulky cobalt sulfides restrict their applications. Here, we proposed an efficient approach for in situ formation of nitrogen site activated cobalt sulfide@N, S dual-doped carbon composite (CS@NSC) by vulcanizing the cobalt-glutamine complex (CG) precursor in a tube furnace. The effects of the molecular structure and calcination temperature of CG precursors on the morphology, structure and electrochemical performance of CS@NSC were studied. The designed CS@NSC-2 exhibited a specific capacity of 593 C g-1 at the current density of 1 A g-1 and good cyclic stability with 88.7% retention after 2000 cycles. Moreover, an asymmetric supercapacitor (ASC) was fabricated by CS@NSC-2 (positive electrode) and activated carbon (AC) (negative electrode), which delivered ultra-high energy density of 67.8 Wh kg-1 at a power density of 400 W kg-1 and possessed 83.1% capacitance retention after 5000 cycles. The eco-friendly method was also suitable for synthesizing nickel sulfide. This work may provide an innovative horizon for the in situ formation of active sites in electrode materials.

FRET-based fluorometry assay for curcumin detecting using PVP-templated Cu NCs.

A novel fluorometric strategy is proposed for detecting curcumin by polyvinyl pyrrolidone-templated Cu NCs (PVP-Cu NCs) as a fluorescent probe which exhibits excitation/emission peaks at 380/510 nm. The fluorescent excitation and emission spectra of PVP-Cu NCs have a striking overlap with the UV-vis spectrum of curcumin, and the fluorescence lifetime of PVP-Cu NCs decreases after the addition of curcumin. Curcumin leads to fluorescence quenching based on fluorescence resonance energy transfer. This method allows for the determination of curcumin in the range of 0.1-10 µg mL-1 and the detection limit is 21 ng mL-1. Furthermore, this method displays good selectivity and is successfully applied for real sample analysis.

Tri-(Fe/F/N)-doped porous carbons as electrocatalysts for the oxygen reduction reaction in both alkaline and acidic media.

Developing a low cost, sustainable and high-performance precious-metal free catalyst to replace platinum (Pt)-based catalysts for the oxygen reduction reaction (ORR) in fuel cells has recently attracted significant attention. It is crucial to produce more abundant and more uniformly dispersed ORR active sites for improving the ORR performance of the catalyst. Herein, we synthesized tri-(Fe/F/N)-doped porous carbons as high-efficiency electrocatalysts for the ORR by using Fe-zeolitic imidazolate framework-8 (Fe-ZIF-8) and ammonium fluoride as precursors. The results indicate that the as-prepared FeFNC-5 catalysts exhibit superior ORR activity, methanol tolerance, and long-term stability compared to commercial 20 wt% Pt/C in both alkaline and acidic media because of the abundant and dispersed Fe-Nx and pyridinic-N active sites, high specific surface area, and hierarchical porous structure. This work provides a new method and insights into the synthesis of Fe, F, and N triple-doped porous carbons as high-efficiency ORR electrocatalysts.

Designed MnS/Co9S8 micro-flowers composites with serrate edges as high-performance electrodes for asymmetric supercapacitor.

The three-dimensional (3D) MnS/Co9S8 (MCS) micro-flowers composites with serrate edges on Ni foam were successfully prepared by a facile hydrothermal method. The time-dependent experiments showed that the structure was assembled by two-dimensional (2D) nanobelts. The serrate edges structures of MCS can enrich electroactive sites and enhance the specific capacity (1070 C/g at 1 A/g). In addition, MCS exhibited good cycling stability of 86% after 1000 cycles. Further, an asymmetric supercapacitor device was constructed by using MCS as the positive electrode and activated carbon (AC) as the negative electrode, which exhibited high energy density of 34.1 Wh/kg at power density of 400 W/kg with good cycling stability. The superior electrochemical performances demonstrated that the micro-flowers composites with serrate edges could offer a new opportunity in developing energy storage devices.

DNA-assisted synthesis of nickel cobalt sulfide nanosheets as high-performance battery-type electrode materials.

Nickel-cobalt sulfide (NiCo2S4) nanosheets were successfully fabricated by an environment-friendly hydrothermal method with the assistance of DNA molecules. Different morphological samples were prepared by adjusting the concentrations of DNA. The NiCo2S4 nanosheets derived from 0.2 µg/mL DNA (denoted as DS2) exhibited a desirable mesoporous feature with superior electrochemical performance compared with other samples. As a battery-type electrode material, it exhibited a high specific capacity of 644C g-1 at the current density of 1 A/g, superior rate capability of 74.3% retention at 15 A/g and remarkable cycling stability of 90.5% after 1500 cycles. Thus, the electrode material of NiCo2S4 nanosheets assisted by DNA molecule offered great potential in eco-friendly energy storage device applications.