pH-Switched Near-Infrared Fluorescent Strategy for Ratiometric Detection of ONOO- in Lysosomes and Precise Imaging of Oxidative Stress in Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is well-known as a kind of autoimmune disease, which brings unbearable pain to the patients by multiple organ complications besides arthritis. To date, RA can be hardly cured, but early diagnosis and standard treatment can relieve symptoms and pain. Therefore, an effective tool to assist the early diagnosis of RA deserves considerable attention. On account of the overexpressed ONOO- during the early stage of RA, a near-infrared (NIR) receptor, Lyso-Cy, is proposed in this work by linker chemistry to expand the conjugated rhodamine framework by cyanine groups. Contributed by the pH-sensitive spiral ring in rhodamine, receptor Lyso-Cy has been found to be workable in lysosomes specifically, which was confirmed by the pH-dependent spectra with a narrow responding region and a well-calculated pKa value of 5.81. We presented an excellent ratiometric sensing protocol for ONOO- in an acidic environment, which was also available for targeting ONOO- in lysosomes selectively. This innovative dual-targeting responsive design is expected to be promising for assisting RA diagnosis at an early stage with respect to the joint inflammatory model established in this work at the organism level.

Synergistic Effects of Pyrrolic N/Pyridinic N on Ultrafast Microwave Synthesized Porous CoP/Ni2P to Boost Electrocatalytic Hydrogen Generation.

Transition metal phosphides are ideal inexpensive electrocatalysts for water-splitting, but the catalytic activity still falls behind that of noble metal catalysts. Therefore, developing valid strategies to boost the electrocatalytic activity is urgent to promote large-scale applications. Herein, a microwave combustion strategy (20 s) is applied to synthesize N-doped CoP/Ni2P heterojunctions (N-CoP/Ni2P) with porous structure. The porous structure expands the specific surface area and accelerates the mass transport efficiency. Importantly, the pyrrolic N/pyridinic N content is adjusted by changing the amount of urea during the synthesis process and then optimizing the adsorption/desorption capacity for H*/OH* to enhance the catalyst activity. Then, the synthesized N-CoP/Ni2P exhibits small overpotentials of 111 and 133 mV for HER in acidic and alkaline electrolytes and 290 mV for OER in alkaline electrolytes. This work provides an original and efficient approach to the synthesis of porous metal phosphides.

CoNiFe alloy nanoparticles encapsulated into nitrogen-doped carbon nanotubes toward superior electrocatalytic overall water splitting in alkaline freshwater/seawater under large-current density.

Developing bifunctional catalysts for overall water splitting with high activity and durability at high current density remains a challenge. In an attempt to overcome this bottleneck, in this work, unique CoNiFe-layered double hydroxide nanoflowers are in situ grown on nickel-iron (NiFe) foam through a corrosive approach and following a chemical vapor deposition process to generate nitrogen-doped carbon nanotubes at the presence of melamine (CoNiFe@NCNTs). The coupling effects between various metal species act a key role in accelerating the reaction kinetics. Moreover, the in situ formed NCNTs also favor promoting electrocatalytic activity and stability. For oxygen evolution reaction it requires low overpotentials of 330 and 341 mV in 1M KOH and 1M KOH + seawater to drive 500 mA cm-2. Moreover, water electrolysis can be operated with CoNiFe@NCNTs as both anode and cathode with small voltages of 1.95 and 1.93 V to achieve 500 mA cm-2 in 1M KOH and 1M KOH + seawater, respectively.

MnOx Film-Coated NiFe-LDH Nanosheets on Ni Foam as Selective Oxygen Evolution Electrocatalysts for Alkaline Seawater Oxidation.

Compared to freshwater electrolysis, seawater electrolysis to produce hydrogen is preferable and more promising, but this technology is plagued by the electrode's corrosion and oxidative reactions of the competitive Cl- ion on the anode. To develop efficient oxygen evolution reaction (OER) catalysts for seawater electrolysis, the ultrathin MnOx film-covered NiFe-layered double-hydroxide nanosheet array is directly assembled on Ni foam (MnOx/NiFe-LDH/NF) by hydrothermal and electrodeposition in turn. This catalyst demonstrates excellent OER-selective activity in alkaline saline electrolytes. In 1 M KOH/0.5 M NaCl and 1 M KOH/seawater electrolytes, MnOx/NiFe-LDH/NF exhibits lower overpotentials at 100 mA cm-2 (η100 values of 265 and 276 mV, respectively) and Tafel slopes (73 and 77 mV decade-1, respectively) than does the NiFe-LDH/NF electrode (η100 values of 298 and 327 mV and Tafel slopes of 91 and 140 mV decade-1, respectively). In alkaline saline solutions, the stability and durability of the former are also better than those of the latter. The good OER selectivity and catalytic performance are attributed to the MnOx overlayer that selectively blocks Cl- anions from approaching catalytic centers, and the good conductivity, fast kinetics, more oxygen vacancies, and abundant active sites of MnOx/NiFe-LDH/NF. The robust stability is due to the enhanced resistance for Cl- corrosion stemming from the MnOx protective film. Hence, MnOx/NiFe-LDH/NF can act as a promising OER electrocatalyst for alkalized natural seawater electrolysis.

Sonication-Free Dispersion of Single-Walled Carbon Nanotubes for High-Sorption-Capacity Aerogel Fabrication.

Homogenously dispersing single-walled carbon nanotubes (SWNTs) in solvents has been one critical step towards exploiting their exceptional properties in high-performance components. However, the solubility of SWNTs is severely limited by the inert tube surfaces and strong tube-tube van der Waals attractions. Starting with carbon nanotubides, i.e., negatively charged SWNTs reduced by alkali metals, we herein propose a sonication-free approach to prepare an aqueous dispersion of SWNTs. The approach combines the spontaneous dissolution of nanotubides in polar aprotic solvents with polyvinylpyrrolidone wrapping and dialysis in deionized H2O, which results in well-dispersed, neutralized SWNTs. The gelation of concentrated SWNT dispersion leads to the formation of hydrogels, which is subsequently transformed into SWNT aerogels through lyophilization. The prepared SWNT aerogels exhibit high-mass-sorption capacities for organic solvent absorption, paving the way towards harvesting the extraordinary properties of SWNTs.

Self-supported Ru-Fe-Ox nanospheres as efficient electrocatalyst to boost overall water-splitting in acid and alkaline media.

Developing electrocatalysts with high activity and durability for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in both acidic and alkaline electrolytes remains challenging. In this study, we synthesize a self-supported ruthenium-iron oxide on carbon cloth (Ru-Fe-Ox/CC) using solvothermal methods followed by air calcination. The morphology of the nanoparticle exposes numerous active sites vital for electrocatalysis. Additionally, the strong electronic interaction between Ru and Fe enhances electrocatalytic kinetics optimization. The porous structure of the carbon cloth matrix facilitates mass transport, improving electrolyte penetration and bubble release. Consequently, Ru-Fe-Ox/CC demonstrates excellent catalytic performance, achieving low overpotentials of 32 mV and 28 mV for HER and 216 mV and 228 mV for OER in acidic and alkaline electrolytes, respectively. Notably, only 1.48 V and 1.46 V are required to reach 10 mA cm-2 for efficient water-splitting in both mediums, exhibiting remarkable stability. This research offers insights into designing versatile, highly efficient catalysts suitable for varied pH conditions.

A near-IR ratiometric fluorescent probe for the precise tracking of senescence: a multidimensional sensing assay of biomarkers in cell senescence pathways.

Senescence is a complex physiological process that can be induced by a range of factors, and cellular damage caused by reactive oxygen species (ROS) is one of the major triggers. In order to learn and solve age-related diseases, tracking strategies through biomarkers, including senescence-associated ß-galactosidase (SA-ß-gal), with high sensitivity and accuracy, have been considered as a promising solution. However, endogenous ß-gal accumulation is not only associated with senescence but also with other physiological processes. Therefore, additional assays are needed to define cellular senescence further. In this work, a fancy fluorescent probe SA-HCy-1 for accurately monitoring senescence is developed, with SA-ß-gal and HClO as targets under high lysosomal pH conditions (pH > 6.0) specifically, on account of the role ß-gal commonly played as an ovarian cancer biomarker. Therefore, precise tracking of cellular senescence could be achieved in view of these three dimensions, with response in dual fluorescence channels providing a ratiometric sensing pattern. This elaborate strategy has been verified to be suitable for biological applications by skin photo-aging evaluation and cellular passage tracing, displaying a significantly improved sensitivity compared with the commercial X-gal kit measurement.