Self-Curing Phthalonitrile Resin with Disulfide Bond as the Curing Group

To further investigate the presence of a radical mechanism in the curing process of phthalonitrile resins, a conventional radical initiation unit (disulfide segment) was introduced into phthalonitrile resins for the first time. A disulfide-bond-containing phthalonitrile monomer (DPBPN) was successfully synthesized. Its self-curing reaction could be promoted by disulfide segments in the precursor. Rheological measurements and differential scanning calorimetry showed that DPBPN exhibited a low melting point (124.5 °C) and a wide processing window (120 °C). Infrared spectroscopy confirmed the formation of isoindoline, triazine, and phthalocyanine structures in the product. Thermal gravimetric analysis and dynamic mechanical analysis suggested the outstanding thermal stability and high glass transition temperature (Tg) of the cured resin with a moderate curing process

Self-Assembled DNA Generated Electric Current Biosensor for HER2 Analysis

We have developed a new DNA self-assembly amplification technology that generates electric current for electrochemical biosensing. The new technology was used for detection of human epidermal growth factor receptor 2 (HER2). In our technology, an aptamer was utilized both as a ligand for recognition and as a signal generating reporter. The aptasensor is based on a sandwich format and a DNA primer on a HER2 aptamer initiates auxiliary DNA self-assembled on the electrode to form a long one-dimensional DNA. The resulting DNA is then reacted with molybdate to generate electrochemical current. The sensitivity of the aptasensor with DNA self-assembly was greater than that of the aptasensor without DNA self-assembly due to the extended length of the DNA strand. Aptasensor analysis of HER2 in serum of breast cancer patients and healthy individuals is highly correlated (<i>R</i>² = 0.9924) with ELISA measurements, with a <i>p</i> value of 1.37 × 10^–7. The analysis of HER2 in serum (confirmed by ELISA) suggests that HER2 levels in breast cancer patients are much higher than healthy individuals. For HER2 positive patients, the levels are higher than those of HER2 negative patients. After surgery, there is a drop of HER2 levels in serum, suggesting potential clinical applications of the new self-assembled DNA electric current generating biosensor. Unlike proteins, DNA is easily amplifiable. The DNA signal amplification method presented here enables effective current generation, which can find wide range of biomedical applications for protein detection

Bio-Based Adenine-Derived Polyimide as a Dual-Functional Binder for the Silicon Anode in Lithium-Ion Batteries

Silicon represents one of the most promising candidates for anode materials in the forthcoming generation of lithium-ion batteries. However, the practical implementation of silicon as an anode material is hindered by the tremendous volume expansion during battery cycling, ultimately leading to a rapid capacity degradation. The development of advanced binders stands out as a highly effective strategy for enhancing the cycling stability of silicon anodes. Herein, we construct bio-based adenine-containing polyimides (APIs) as a dual-functional binder for lithium-ion batteries. Due to the dual interfacial interactions of adenine segments with the silicon and the conductive carbon, the API can restrain the silicon volume expansion and maintain the electrode structure integrity, contributing to the stable solid electrolyte interphase and improved conductivity pathway. Compared with the conventional polyimides (PI), API exhibits slower capacity decay and excellent rate performance, as well as better cycling stability than poly(vinylidene fluoride), sodium carboxymethyl cellulose, and poly acrylic acid binders. This molecular structure design provides insights for the preparation of multifunctional high-performance binders for the silicon anode

MOF-Templated Fabrication of Hollow Co₄N@N-Doped Carbon Porous Nanocages with Superior Catalytic Activity

Metallic Co₄N catalysts have been considered as one of the most promising non-noble materials for heterogeneous catalysis because of their high electrical conductivity, great magnetic property, and high intrinsic activity. However, the metastable properties seriously limit their applications for heterogeneous water phase catalysis. In this work, a novel Co-metal–organic framework (MOF)-derived hollow porous nanocages (PNCs) composed of metallic Co₄N and N-doped carbon (NC) were synthesized for the first time. This hollow three-dimensional (3D) PNC catalyst was synthesized by taking advantage of Co-MOF as a precursor for fabricating 3D hollow Co₃O₄@C PNCs, along with the NH₃ treatment of Co-oxide frames to promote the in situ conversion of Co-MOF to Co₄N@NC PNCs, benefiting from the high intrinsic activity and electron conductivity of the metallic Co₄N phase and the good permeability of the hollow porous nanostructure as well as the efficient doping of N into the carbon layer. Besides, the covalent bridge between the active Co₄N surface and PNC shells also provides facile pathways for electron and mass transport. The obtained Co₄N@NC PNCs exhibit excellent catalytic activity and stability for 4-nitrophenol reduction in terms of low activation energy (<i>E</i>_a = 23.53 kJ mol^–1), high turnover frequency (52.01 × 10²⁰ molecule g^–1 min^–1), and high apparent rate constant (<i>k</i>_app = 2.106 min^–1). Furthermore, its magnetic property and stable configuration account for the excellent recyclability of the catalyst. It is hoped that our finding could pave the way for the construction of other hollow transition metal-based nitride@NC PNC catalysts for wide applications

Oxygen Vacancy-Reinforced Water-Assisted Proton Hopping for Enhanced Catalytic Hydrogenation

Water-assisted proton hopping (WAPH) has been intensively investigated for promoting the performance of metal oxide-supported catalysts for hydrogenation. However, the effects of the structure of the metal oxide support on WAPH have received little attention. Herein, we construct oxygen vacancy-bearing, MoO3–x-supported Pd nanoparticle catalysts (Pd/MoO3–x-R), where the oxygen vacancies can promote WAPH, thereby facilitating catalytic hydrogenation. The experimental results and theoretical calculations show that the oxygen vacancies favor the adsorption of water, which assists the proton hopping across the surface of the metal oxide, enhancing the catalytic hydrogenation. Our finding will provide a potential approach to the design of metal oxide-supported catalysts for hydrogenation

Effect of suppressed PGC-1α expression on OA-induced VSMC proliferation and migration.

<p>VSMCs were transfected with siRNA S1 or the negative control (siRNA N). The interference effect was assessed by quantitative PCR (A) and western blot (B). Effects of decreased PGC-1α on OA-induced VSMC proliferation were determined by MTT assay (C) and cell counting (D). Effects of decreased PGC-1α on OA-induced VSMC migration were determined by wound healing (E) and transwell analysis (F). Data in VSMC proliferation and migration detections represent the means±SEM of 18 determinants from 3 independently prepared samples each with 6 measurements. Data in PGC-1α mRNA level detections are expressed as means±SEM of five different experiments normalized to β-actin levels. Data in PGC-1α protein level detections are expressed as means±SEM of four different experiments normalized to GAPDH levels. **P<0.01, #P<0.001 vs. control or N group.</p

Effects of PGC-1α on OA-induced p-ERK activity in VSMCs.

<p>PDGF-BB and pharmacological ERK-MAPK inhibitor PD98059 were chosen as positive and negative controls of ERK phosphorylation, respectively. VSMCs were made quiescent by serum-starvation for 24 h and then stimulated with PDGF-BB (100 ng/ml) for 30 min, PD98059 (50 uM) for 1 h before stimulation with PDGF-BB (100 ng/mL), or 0.4 mmol/L OA for 2 h. Proteins extracted following these treatments and phosphorylation of ERK was determined by western blot (A). VSMCs were also treated with 48 h adenovirus infection and then incubated with 0.4 mmol/L OA for 24 h. Phosphorylation of ERK was also analyzed with elevated PGC-1α level by western blot (B). Data were shown as the ratio of p-ERK/total ERK. The ratios of control were designated as 1.0. Individual data in this chart represent the mean±SEM of 4 determinants. #P<0.001 vs. control or positive/negative group.</p

Effect of overexpressed PGC-1α on OA-induced VSMC proliferation and migration.

<p>VSMCs were treated with 48 h adenovirus infection, then incubated with 0.4 mmol/L OA for 24 h. PGC-1α expression was analysised by quantitative PCR (A) and western blot (B). Effects of PGC-1α overexpression on OA-induced VSMC proliferation were determined by MTT assay (C) and cell counting (D). Effects of PGC-1α overexpression on OA-induced VSMC migration were determined by wound healing (E) and transwell analysis (F). Data in VSMC proliferation and migration detections represent the means±SEM of 18 determinants from 3 independently prepared samples each with 6 measurements. Data in PGC-1α mRNA level detections are expressed as means±SEM of five different experiments normalized to β-actin levels. Data in PGC-1α protein level detections are expressed as means±SEM of four different experiments normalized to GAPDH levels. *P<0.05, **P<0.01, #P<0.001 vs. control or GFP group.</p

Changes of PGC-1α expression and VSMC proliferation/migration in response to increased proportion of PA in fatty acid mixtures.

<p>VSMCs were incubated with various FFAs for 24 h before analysis. Effects of PA on PGC-1α expression was determined by quantitative PCR (A) and western blot analysis (B). Effects of increased PA on PGC-1α expression were determined by quantitative PCR (C). Effects of increased PA on OA-induced VSMC proliferation were determined by MTT assay (D) and cell counting (E). Effects of increased PA on OA-induced VSMC migration were determined by wound healing (F) and transwell analysis (G,H). Data in VSMC proliferation and migration detections represent the means±SEM of 18 determinants from 3 independently prepared samples each with 6 measurements. Data in PGC-1α mRNA level detections are expressed as means±SEM of five different experiments normalized to β-actin levels. Data in PGC-1α protein level detections are expressed as means±SEM of four different experiments normalized to GAPDH levels. *P<0.05, **P<0.01, #P<0.001 vs. control</p