Designed Monomers and Polymers最新文献

The donor-acceptor type π-conjugated polymers having heterole units were prepared by the reaction of a regioregular organometallic polymer having both reactive titanacyclopentadiene and electron-donor thiophene-2,5-diyl units in the main chain with electrophiles such as diphenyltin dichloride, dichlorophenylphosphine, and diiodophenylarsine. For example, a polymer having electron-accepting phosphole unit was obtained in 54% yield whose number-average molecular weight (M_n) and molecular weight distribution (M_w/M_n) were estimated as 3,000 and 1.9, respectively. The obtained polymer exhibits a high highest occupied molecular orbital (HOMO) and low lowest unoccupied molecular orbital (LUMO) energy levels (-5.13 eV and -3.25 eV, respectively) due to the electron-donating thiophene and electron-accepting phosphole units. Reflecting upon the alternating structure of thiophene and phosphole, the polymer exhibits a band gap energy level (E_g) of 1.78 eV which is narrower than that of a derivative of poly(thiophene) (E_g = 2.25 eV).

Polyhydroxyalkanoates (PHAs) are biopolymers that are produced within the microbial cells in the presence of excess carbon and nutrient limitation. Different strategies have been studied to increase the quality and quantity of this biopolymer which in turn can be utilized as biodegradable polymers replacing conventional petrochemical plastics. In the present study, Bacillus endophyticus, a gram-positive PHA-producing bacterium, was cultivated in the presence of fatty acids along with beta-oxidation inhibitor acrylic acid. A novel approach for incorporating different hydroxyacyl groups provided using fatty acids as co-substrate and beta-oxidation inhibitors to direct the intermediates to co-polymer synthesis was experimented. It was observed that higher fatty acids and inhibitors had a greater influence on PHA production. The addition of acrylic acid along with propionic acid had a positive impact, giving 56.49% of PHA along with sucrose which was 1.2-fold more than the control devoid of fatty acids and inhibitors. Along with the copolymer production, the possible PHA pathway functional leading to the copolymer biosynthesis was hypothetically interpreted in this study. The obtained PHA was analyzed by FTIR and ¹H NMR to confirm the copolymer production, which indicated the presence of poly3hydroxybutyrate-co-hydroxyvalerate (PHB-co-PHV), poly3hydroxybutyrate-co-hydroxyhexanoate (PHB-co-PHx).

Morphine is a widely used opioid analgesic. However, standard morphine dosages and administration methods exhibit a short half-life and pose a risk of respiratory depression. Sustained-release microspheres can deliver prolonged efficacy and reduce side effects. We present a new controlled-release morphine gelatine microsphere (MGM) prepared using an emulsification-crosslinking strategy. The gelatine microsphere design improves the bioavailability of morphine. And it not only increases the clinical analgesic efficacy but also the safety of clinical medication through a gradual, sustained release. Besides, we describe MGMs' preparation, release, pharmacodynamics, and pharmacokinetics. And the drug metabolism pathway. We calculate the release rate of morphine by measuring plasma morphine concentration over time and pharmacokinetic parameters. It optimized the manufacturing process of MGMs, which makes the analgesic effect have a longer duration. MGMs analgesic effect shows dose dependence. After they were administrated, MGMs were released more slowly. Peak concentration was reduced, and the relative bioavailability improved. It even reached 88.84%. Its pharmacokinetic process was consistent with the two-component first-order absorption model. MGMs deliver sustained-release and long-action pharmacokinetics. It shows design goals of improving drug bioavailability, prolonging drug residence time in vivo, and maintaining stable blood drug concentration.

Recent years have witnessed an enormous development in photoinduced systems, opening up possibilities for advancements in industry and academia in terms of green chemistry providing environmentally friendly conditions and spatiotemporal control over the reaction medium. A vast number of research have been conducted on photoinduced systems focusing on the development of new polymerization methods, although scarcely investigated, depolymerization of the synthesized polymers by photochemical means is also possible. Herein, we provide a comprehensive study of visible light induced dimanganese decacarbonyl (Mn₂(CO)₁₀) assisted depolymerization system for poly(methyl methacrylate) with chlorine chain end prepared by Atom Transfer Radical Polymerization. Contrary to the conventional procedures demanding high temperatures, the approach offers ambient temperature for the photodepolymerization process. This novel light-controlled concept is easily adaptable to macroscales and expected to promote further research in the fields matching with the environmental concerns.

Well-defined functional poly(p-phenyl styrenesulfonate) and poly(p-phenyl styrene-sulfonate-co-styrene) were successfully synthesized by the atom transfer radical polymerization (ATRP) using CuBr/bpy(PMDETA) catalyst and 1-phenylethyl bromide (1-PEBr) as an ATRP initiator in diphenyl ether (DPE) or dimethyl formamide (DMF). In both homo- and copolymers, the CuBr/PMDETA catalytic system in DPE or DME showed higher yield than CuBr/bpy and the polydispersity index (PDI) of polymer was low. Using PMDETA or bpy as a ligand in DMF, the high yield with high PDI was obtained than in DPE. We found that the CuBr/PMDETA catalyzed ATRP of p-phenyl styrenesulfonate and copolymerization with styrene comonomer in DPE proceeded in a controlled manner. The polymers containing sulfonic acid were obtained by the chemical deprotection of protecting group, followed by acidification. The molecular structure, molecular weights and thermal properties of the copolymers were determined by nuclear magnetic resonance (¹H NMR) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, size exclusion chromatography (SEC), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively.

A new thermostable Co(II)-based compound, namely [Co₃(L)₂(HTEA)₂]_n (1, HL = isonicotinic acid, H₃TEA = triethanolamine), has been successfully synthesized by the isomicotinic acid ligand and HTEA anion. The photocatalytic property of 1 was also investigated, indicating that it shows excellent photocatalytic activity for the degradation of Rhodamine B (MB) solution under the UV light irradiation. For the treatment of trigeminal neuralgia, the content of the inflammatory cytokines released into the trigeminal ganglion tissue fluid was measured with enzyme-linked immunosorbent assay (ELISA) assay. Then, the real-time Reverse Transcription-Polymerase Chain Reaction (RT-PCR) was conducted and the activation of the nuclear factor kappa-B (NF-κB) inflammatory signaling pathway was measured.

Sesamin, a significant lignin compound isolated from sesame (Sesamum indicum Linn), is well known for its antioxidant, anti-inflammatory, and tissue growth promotion properties. Bioabsorbable poly(ε-caprolactone) (PCL) is also a well-known polymer applied to various fields of medicine as biomaterials. The main objective of this research was to produce a prototype material from PCL and sesamin by electrospinning technique for bone tissue engineering applications. Dichloromethane and dimethylformamide (7:3) mixture was used as the solvent system for fabrication of PCL nanofiber with different loads of sesamin concentrations (1-6 wt%). The crystallinity levels decreasing and the entrapment efficiency increasing (86.87%-93.97%) were observed while sesamin concentrations were increased. The infrared spectra of electrospun mats confirmed that sesamin corporated into fibrous networks. The sesamin-loaded PCL nanofibrous membranes showed a significant release of sesamin in the range of 1.28-8.16 μg/mL within 10 weeks. The release data were fitted to zero order, first order, Higuchi and Korsmeyer-Peppas models to evaluate sesamin-releasing mechanisms and kinetics. The releasing kinetics of sesamin followed the Fickian diffusion mechanism of Korsmeyer-Peppas (R² = 0.99). In vitro experiments with an osteosarcoma cell line (MG-63) revealed cell attachment, biocompatibility, and promotion of bone marker expression, the alkaline phosphatase (ALP) activity were studied. The electrospun PCL nanofiber loaded with sesamin had the potential as a scaffold for sesamin delivery to bone cells and applications in biomedicine.

Development of polymer-based flooding technology to improve oil recovery efficiency, water dispersion copolymerization of acrylamide, cationic monomer methacryloxyethyltrimethyl ammonium chloride (METAC), and anionic monomer acrylic acid (AA) were carried out in aqueous ammonium sulfate solution with polyvinyl pyrrolidone (PVP) as the stabilizer. The copolymers were characterized by ¹H-NMR, FT-IR, TG, and SEM to confirm that they were prepared successfully and exhibited excellent salt-resistant property. Moreover, the effect of the aqueous solution of ammonium sulfate (AS) concentration, stabilizer concentration, and initiator concentration on the viscosity and size were systematically investigated. To further improve the thermal endurance properties of copolymer, hydrophobic monomers with different alkyl chain lengths were added to the above system. The acrylamide-based quadripolymer possessed prominent thermal and salt endurance properties by utilizing the advantages of zwitterionic structure and hydrophobic monomer. With the temperature rising, the viscosity retention could reach 70.2% in the water and 63.8% in the saline. This work had expected to provide a new strategy to design polymers with excellent salinity tolerance and thermal-resistance performances.

Hyaluronic acid (HA) is a naturally occurring biopolymer, with a remarkable wound healing property. Zinc-oxide non-eugenol is a material widely used for periodontal dressing in dentistry. However, it has been reported that zinc oxide non-eugenol is toxic to osteoblasts and fibroblasts. Hence, the present study aimed to evaluate the drug release and cytotoxicity of HA and zinc-oxide gels. Hydrogels of HA and zinc oxide were formulated with carbopol as a carrier. In vitro drug release was performed by UV spectrophotometry, dialysis, and vial bag methods. Cytotoxicity assessment of HA and zinc-oxide gels was performed in human periodontal ligament fibroblasts (HPdLF) and human gingival fibroblasts (hGFs). An inverted phase-contrast microscope was used to assess the morphological changes. At 24 and 48 hr, HPdLF cells showed the highest viability in 0.1% low molecular weight-HA (LMW-HA) with a median value of 131.9, and hGFs showed the highest viability in 5% LMW-HA with a median of 129.56. The highest viability of HPdLF cells was observed in 5% high molecular weight-HA (HMW-HA), with a median value of 127.11. hGFs showed the highest viability in 1% HMW-HA with a median value of 97.99. Within the limitations of the present study, we concluded that LMW-HA is more efficient than HMW-HA. Both HPdLF and hGF cells showed complete cell morbidity with zinc-oxide hydrogels. Therefore, zinc oxide-based gels in concentrations as low as 9% could be toxic intraorally to soft tissues that harbor gingival and periodontal ligament fibroblasts.

Through the self-assembly reaction of 5-substituted isophthalic acid and bis(imidazolyl) ligands with Cd(II) ion or Zn(II) ion, two new coordination polymers with the chemical formulae of [Cd(5-meo-ip)(bmip)]_n (1) and [Zn(5-pro-ip)(bip)]_n·2 n(H₂O) (2) (5-meo-H₂ip = 5-methoxyisophthalic acid, 5-pro-H₂ip = 5-propoxyisophthalic acid, bmip = 1,3-bis(2-methylimidazolyl)propane bip = 1,3-bis(imidazolyl)propane) were successfully obtained and structurally characterized by a series of characterization techniques. Moreover, compounds 1-2 show intense blue luminescence at room temperature. Furthermore, the assessment of their treatment activity on the uterine fibroids combined with ultrasound therapy was evaluated and the specific mechanism was investigated at the same time. Firstly, the effect of compound treatment on uterine fibroids apoptosis was detected via flow cytometry. Next, the apoptotic signaling pathway activation was detected through the Caspase-3 and Caspase-8 Activity Assay Kit.