Encapsulation Mechanism of Molecular Nanocarriers Based on Unimolecular Micelle Forming Dendritic Core−Shell Structural Polymers

A series of dendritic core−shell structural polymers with different shell densities were synthesized based on dendritic polyester Boltorn H40 and were demonstrated to form unimolecular micelles in chloroform. The encapsulation mechanism study using Congo red as a guest molecule by fluorescence and UV−vis methods showed that the interaction of Congo red with hydroxyl groups in the dendritic core−shell polymer led to encapsulation. Moreover, the results also indicated that the dendrimer with 43.4% hydroxyl groups end-capped by the long alkyl chains showed the best encapsulation capacity. However, lower and higher alkyl densities both led to lower encapsulation capacities. The former was attributed to the poor compatibility of the polymer with chloroform, and the later was caused by less location sites for the guest molecule inside the core−shell polymer

Soluble and Meltable Hyperbranched Polyborosilazanes toward High-Temperature Stable SiBCN Ceramics

High-temperature stable siliconborocarbonitride (SiBCN) ceramics produced from single-source preceramic polymers have received increased attention in the last two decades. In this contribution, soluble and meltable polyborosilazanes with hyperbranched topology (hb-PBSZ) were synthesized via a convenient solvent-free, catalyst-free and one-pot A₂ + B₆ strategy, an aminolysis reaction of the A₂ monomer of dichloromethylsilane and the B₆ monomer of tris­(dichloromethylsilylethyl)­borane in the presence of hexamethyldisilazane. The amine transition reaction between the intermediates of dichlorotetramethyldisilazane and tri­(trimethylsilylmethylchlorosilylethyl)­borane led to the formation of dendritic units of aminedialkylborons rather than trialkylborons. The cross-linked hb-PBSZ precursors exhibited a ceramic yield higher 80%. The resultant SiBCN ceramics with a boron atomic composition of 6.0–8.5% and a representative formula of Si₁B_0.19C_1.21N_0.39O_0.08 showed high-temperature stability and retained their amorphous structure up to 1600 °C. These hyperbranched polyborosilazanes with soluble and meltable characteristics provide a new perspective for the design of preceramic polymers possessing advantages for high-temperature stable polymer-derived ceramics with complex structures/shapes

Controlling Poly(3-hexylthiophene) Crystal Dimension: Nanowhiskers and Nanoribbons

Controlling Poly(3-hexylthiophene) Crystal Dimension: Nanowhiskers and Nanoribbon

Polymer-Derived Ceramic Composite Fibers with Aligned Pristine Multiwalled Carbon Nanotubes

Polymer-derived ceramic fibers with aligned multiwalled carbon nanotubes (MWCNTs) are fabricated through the electrospinning of polyaluminasilazane solutions with well-dispersed MWCNTs followed by pyrolysis. Poly(3-hexylthiophene)-b-poly (poly (ethylene glycol) methyl ether acrylate) (P3HT-b-PPEGA), a conjugated block copolymer compatible with polyaluminasilazane, is used to functionalize MWCNT surfaces with PPEGA, providing a noninvasive approach to disperse carbon nanotubes in polyaluminasilazane chloroform solutions. The electrospinning of the MWCNT/polyaluminasilazane solutions generates polymer fibers with aligned MWCNTs where MWCNTs are oriented along the electrospun jet by a sink flow. The subsequent pyrolysis of the obtained composite fibers produces ceramic fibers with aligned MWCNTs. The study of the effect of polymer and CNT concentration on the fiber structures shows that the fiber size increases with the increment of polymer concentration, whereas higher CNT content in the polymer solutions leads to thinner fibers attributable to the increased conductivity. Both the SEM and TEM characterization of the polymer and ceramic fibers demonstrates the uniform orientation of CNTs along the fibers, suggesting excellent dispersion of CNTs and efficient CNT alignment via the electrospinning. The electrical conductivity of a ceramic fibers with 1.2% aligned MWCNTs is measured to be 1.58 × 10−6 S/cm, which is more than 500 times higher than that of bulk ceramic (3.43 × 10−9 S/cm). Such an approach provides a versatile method to disperse CNTs in preceramic polymer solutions and offers a new approach to integrate aligned CNTs in ceramics

Interparticle Electromagnetic Coupling in Assembled Gold-Necklace Nanoparticles

A unique phenomenon of interparticle electromagnetic coupling in closely spaced gold nanoparticles has been observed by probing the ultrafast electron dynamics of spherical gold nanoparticles with those of a gold-necklace nanoparticle system. Electron−electron scattering and electron−phonon relaxation (two main aspects of electron dynamics) are found to be significantly different for gold-necklace particles when compared to spherical gold nanoparticles. On inter band gap excitation, appreciably slower and pump-power independent electron−electron scattering has been observed for necklace particles (∼500 fs for Au-neck compared to ∼200 fs for Au-spherical nanoparticles). Significantly slower pump-power dependent electron−phonon relaxation has also been observed for the necklace particle system. The electron dynamics for gold-necklace particles is quite unique, and existing models of electron−electron scattering and electron−phonon relaxation were unsuccessful in explaining the dynamics in this system. The results are thus explained by incorporating efficient dipolar electronic coupling between the neighboring nanoparticles

Fluorescence Imaging-Incorporated Transcriptome Study of Glutathione Depletion-Enhanced Ferroptosis Therapy via Targeting Gold Nanoclusters

Ferroptosis plays an important role in tumor inhibition and is a new type of programmed cell death. Recent studies have shown that glutathione (GSH) depletion is an effective method to enhance the therapeutic efficacy of ferroptosis; however, a systematic investigation of the phenomenon is limited. Herein, we provide a facile fluorescence imaging-incorporated transcriptome strategy to visualize the process and explore the mechanism of GSH depletion-enhanced ferroptosis. The proposed multifunctional nanoplatform is achieved using simple transferrin receptor aptamer-functionalized fluorescent gold nanoclusters (termed TfRA-AuNCs), which exhibit efficient hydroxyl radical generation and GSH-depleting capabilities. Live cell fluorescence imaging results revealed that TfRA-AuNCs were endocytosed into 4T1 cells and were mostly distributed in lysosomes. In vitro results indicated that TfRA-AuNCs enhanced the ferroptosis effect in 4T1 cells. Importantly, transcriptome analysis indicated that 4T1 cells treated with TfRA-AuNCs regulated the expression change of ferroptosis-related genes, and the Kyoto Encyclopedia of Genes and Genomes pathway identified the GSH metabolism pathway involved in ferroptosis, thus revealing the exact molecular mechanism of ferroptosis induced by TfRA-AuNCs at the RNA level. Furthermore, in vivo results confirmed the tumor inhibition effect, tumor-targeted fluorescence imaging, and long-term biocompatibility after TfRA-AuNC treatment. This study introduces a new possibility for the mechanistic study of nanoagent-induced ferroptosis in tumor treatment

New Indole-Based Light-Emitting Oligomers: Structural Modification, Photophysical Behavior, and Electroluminescent Properties

A novel series of indole-based conjugated oligomers were synthesized by Wittig−Horner−Emmons olefination from the aryl-bridged bisindole aldehydes and the corresponding bisphosphonates. The introduction of indole into the light-emitting materials made these oligmers exhibit favorable properties. They were thermally stable, and the UV−vis spectra of the oligomers could be modulated by the arylenevinylene units; their PL and EL spectra also showed similar properties that can be further modulated. The highest luminance achieved in a device with the configuration ITO/PEDOT:PSS/oligomer/Ba/Al was 2536 cd/m2 at 7.5 V for oligomer P6, and the highest external EL quantum efficiency of 0.39% and luminous efficiency of 0.97 cd/A were attained by oligomer P1

Image1_Adjuvant therapy with Huatan Sanjie Granules improves the prognosis of patients with primary liver cancer: a cohort study and the investigation of its mechanism of action based on network pharmacology.TIF

Objective: Nowadays, primary liver carcinoma (PLC) is one of the major contributors to the global cancer burden, and China has the highest morbidity and mortality rates in the world. As a well-known Chinese herbal medicine (CHM) prescription, Huatan Sanjie Granules (HSG) has been used clinically for many years to treat PLC with remarkable efficacy, but the underlying mechanism of action remains unclear.Methods: A clinical cohort study was conducted to observe the overall survival of PLC patients with vs. without oral administration of HSG. Meanwhile, the BATMAN-TCM database was used to retrieve the potential active ingredients in the six herbs of HSG and their corresponding drug targets. PLC–related targets were then screened through the Gene Expression Omnibus (GEO) database. The protein–protein interaction (PPI) network of targets of HSG against PLC was constructed using Cytoscape software. The cell function assays were further carried out for verification.Results: The results of the cohort study showed that the median survival time of PLC patients exposed to HSG was 269 days, which was 23 days longer than that of the control group (HR, 0.62; 95% CI, 0.38–0.99; p = 0.047). In particular, the median survival time of Barcelona Clinic Liver Cancer stage C patients was 411 days in the exposure group, which was 137 days longer than that in the control group (HR, 0.59; 95% CI, 0.35–0.96; p = 0.036). Meanwhile, the enrichment analysis result for the obtained PPI network consisting of 362 potential core therapeutic targets suggest that HSG may inhibit the growth of liver cancer (LC) cells by blocking the PI3K-Akt/MAPK signaling pathways. Furthermore, the above prediction results were verified by a series of in vitro assays. Specifically, we found that the expressions TP53 and YWHA2, the targets of the hepatitis B virus signaling pathway, were significantly affected by HSG.Conclusion: HSG shows promising therapeutic efficacy in the adjuvant treatment of PLC.</p

Marthiapeptide A, an Anti-infective and Cytotoxic Polythiazole Cyclopeptide from a 60 L Scale Fermentation of the Deep Sea-Derived <i>Marinactinospora thermotolerans</i> SCSIO 00652

A new sequential tristhiazole-thiazoline-containing cyclic peptide, marthiapeptide A (1), was isolated from a 60 L scale culture of the deep South China Sea-derived strain Marinactinospora thermotolerans SCSIO 00652. The planar structure and absolute configuration of 1 were elucidated by application of spectroscopic techniques, as well as by single-crystal X-ray diffraction and chiral-phase HPLC analysis of the acid hydrolysates. Marthiapeptide A (1) exhibited antibacterial activity against a panel of Gram-positive bacteria, with MIC values ranging from 2.0 to 8.0 μg/mL, and displayed strong cytotoxic activity against a panel of human cancer cell lines with IC50 values ranging from 0.38 to 0.52 μM

Ultralight Multiwalled Carbon Nanotube Aerogel

Ultralight multiwalled carbon nanotube (MWCNT) aerogel is fabricated from a wet gel of well-dispersed pristine MWCNTs. On the basis of a theoretical prediction that increasing interaction potential between CNTs lowers their critical concentration to form an infinite percolation network, poly(3-(trimethoxysilyl) propyl methacrylate) (PTMSPMA) is used to disperse and functionalize MWCNTs where the subsequent hydrolysis and condensation of PTMSPMA introduces strong and permanent chemical bonding between MWCNTs. The interaction is both experimentally and theoretically proven to facilitate the formation of a MWCNT percolation network, which leads to the gelation of MWCNT dispersion at ultralow MWCNT concentration. After removing the liquid component from the MWCNT wet gel, the lightest ever free-standing MWCNT aerogel monolith with a density of 4 mg/cm3 is obtained. The MWCNT aerogel has an ordered macroporous honeycomb structure with straight and parallel voids in 50−150 μm separated by less than 100 nm thick walls. The entangled MWCNTs generate mesoporous structures on the honeycomb walls, creating aerogels with a surface area of 580 m2/g which is much higher than that of pristine MWCNTs (241 m2/g). Despite the ultralow density, the MWCNT aerogels have an excellent compression recoverable property as demonstrated by the compression test. The aerogels have an electrical conductivity of 3.2 × 10−2 S·cm−1 that can be further increased to 0.67 S·cm−1 by a high-current pulse method without degrading their structures. The excellent compression recoverable property, hierarchically porous structure with large surface area, and high conductivity grant the MWCNT aerogels exceptional pressure and chemical vapor sensing capabilities