A novel trifunctional initiator with one alkyne and two trifluoromethanesulfonate moieties was synthesized from a protected alcohol 5-hydroxyl-2-phenyl-1, 3-dioxane. The alkyne func- tionalized intermediate with two p...A novel trifunctional initiator with one alkyne and two trifluoromethanesulfonate moieties was synthesized from a protected alcohol 5-hydroxyl-2-phenyl-1, 3-dioxane. The alkyne func- tionalized intermediate with two protected alcohol groups was synthesized by reacting with propargyl bromide. The alcohol groups were cleaved using a mixture of tetrahydrofuran and hydrochloric acid aqueous solution. In the last step the initiator was synthesized us- ing triflic anhydride in carbon tetrachloride. The initiator was characterized by 1H NMR and used for the polymerization of 2-ethyl-2-oxazoline which gives polymers with narrow distribution. For comparison a similar initiator with two tosylates was prepared and used for the polymerization of the monomer 2-ethyl-2-oxazoline, the resulting product has a wide molecular weight distribution and most of the initiator remains unreacted after 24 h which may be due to the steric hindrance between the two tosylate groups. To further explore the steric hindrance phenomenon, a linear tosylate initiator was synthesized, but still some of the initiator remains unreacted, illustrating that both steric hindrance and electrophilic balance affect the efficiency of the cationic ring-opening polymerization. All of the polymers were characterized in detail by using IH NMR, matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy, and size exclusion chromatography to confirm the purity and distribution of the polymers.展开更多
Poly(2-oxazoline)(POx)has been regarded as a potential candidate for drug delivery carrier to meet the challenges of nanomedicine clinical translation,due to its excellent biocompatibility and self-assembly properties...Poly(2-oxazoline)(POx)has been regarded as a potential candidate for drug delivery carrier to meet the challenges of nanomedicine clinical translation,due to its excellent biocompatibility and self-assembly properties.The drug loading capacity and stability of amphiphilic POxs as drug nanocarriers,however,tend to be insufficient.Herein,we report a strategy to prepare nucleobase-crosslinked POx nanoparticles(NPs)with enhanced stability and ultra-high paclitaxel(PTX)loading capacity for breast cancer therapy.An amphiphilic amine-functionalized POx(PMBEOx-NH_(2))was firstly prepared through a click reaction between cysteamines and vinyl groups in poly(2-methyl-2-oxazoline)-block-poly(2–butyl–2-oxazoline-co-2-butenyl-2-oxazoline)(PMBEOx).Complementary nucleobase-pairs adenine(A)and uracil(U)were subsequently conjugated to PMBEOx-NH2 to give functional POxs(POxA and POxU),respectively.Due to the nucleobase interactions formed between A and U,NPs formed by POxA and POxU at a molar ratio of 1:1 displayed ultrahigh PTX loading capacity(38.2%,PTX/POxA@U),excellent stability,and reduced particle size compared to the uncross-linked PTX-loaded NPs(PTX/PMBEOx).Besides the prolonged blood circulation and enhanced tumor accumulation,the smaller PTX/POxA@U NPs also have better tumor penetration ability compared with PTX/PMBEOx,thus leading to a higher tumor suppression rate in two murine breast cancer models(E0711 and 4T1).These results proved that the therapeutic effect of chemotherapeutic drugs could be improved remarkably through a reasonable optimization of nanocarriers.展开更多
This study aimed to investigate the ability of the novel materials D-α-tocopheryl poly(2-ethyl-2-oxazoline) succinate(TPOS) to construct pH-sensitive liposomes. TPOS was initially synthesized and characterized by TLC...This study aimed to investigate the ability of the novel materials D-α-tocopheryl poly(2-ethyl-2-oxazoline) succinate(TPOS) to construct pH-sensitive liposomes. TPOS was initially synthesized and characterized by TLC, FTIR, and ~1H-NMR. The buffering capacity of polyethylene glycol-distearoyl phosphatidylethanolamine(PEG-DSPE) and TPOS was determined by acid-base titration, and TPOS displayed a slower downtrend and gentler slope of titration curve than PEG-DSPE within pH 7.4–5.0. Studies on the in vitro drug release demonstrated that TPOS modified docetaxel(DOC) liposomes(TPOS-DOC-L) had a slower drugrelease rate at pH 7.4 similar to PEGylated-DOC liposomes(PEG-DOC-L), whereas the release rate reached approximately 86.92% ± 1.69% at pH 6.4. In vitro cellular uptake assays by microplate reader, and flow cytometry revealed that TPOS modified coumarin 6 liposomes(TPOS-C6-L) had stronger cellular uptake at pH 6.4 than that at pH 7.4( P < 0.01). Conversely, for PEGylated C6 liposomes(PEG-C6-L) and conventional C6 liposomes(C6-L), very similar cellular uptakes were exhibited at different pH values. Confocal laser scanning microscopy images showed that PEG-C6-L and C6-L were mainly located in lysosomes. By contrast, TPOS-C6-L showed broader cytoplasmic release and distribution at 4 h. MTT assay showed that the cytotoxicity of TPOS-DOC-L was similar to that of PEG-DOC-L and conventional DOC liposomes(DOC-L) at the same DOC concentration and at pH 7.4, but was much lower than those at pH 6.4 after 48 h of incubation. The apoptosis of PEG-DOC-L and DOC-L had no remarkable improvement with decreased pH from 7.4 to 6.4. Meanwhile, TPOS-DOC-Lsignificantly induced the apoptosis of HeLa cells with decreased pH. Therefore, TPOS can be a biomaterial for the construction of a pH-sensitive drug delivery system.展开更多
By mechanism-transformation (anionic --> cationic) poly(styrene-6-2-ethyl-2-oxazoline) diblock copolymer, PS-b-PEOx, was synthesized in two steps. The first step is the polymerization of styrene block capped with e...By mechanism-transformation (anionic --> cationic) poly(styrene-6-2-ethyl-2-oxazoline) diblock copolymer, PS-b-PEOx, was synthesized in two steps. The first step is the polymerization of styrene block capped with ethylene oxide and its tosylation; the second step is the cationic ring-opening polymerization of 2-ethyl-2-oxazoline. The products were thoroughly characterized by various methods, such as H-1-NMR, IR, DMA, TEM and SAXS. The results show that the copolymer obtained possesses high molecular weight and narrow molecular weight distribution.展开更多
Functional multiblock poly(ether-b-amide)(PEBA)copolymers,comprised of PA1212(polyamide 1212)as hard segments and Jeffamine ED-2003 as soft segments,were successfully prepared via two-step melt polycondensation withou...Functional multiblock poly(ether-b-amide)(PEBA)copolymers,comprised of PA1212(polyamide 1212)as hard segments and Jeffamine ED-2003 as soft segments,were successfully prepared via two-step melt polycondensation without any amidation catalyst.Here,using diamino-terminated poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide)(PPO-PEO-PPO),Jeffamine ED-2003,enhances the compatibility between polyamide oligomer and polyether,which is better than the traditional route using hydroxyl-terminated polyether.The chemical structure of multiblock PEBAs,as well as the microphase separated structure with crystalline phase of polyamide and polyether,were confirmed by heteronuclear multiple-bond correlation spectrum,heteronuclear multiple quantum correlation spectrum,Fourier transform infrared spectroscopy(FT-IR),differential scanning calorimetry and dynamic mechanical analysis.The hydrophilic PEBA copolymers showed water adsorption ranging from 87.3%to 17.1%depending on the polyether content,and specially showed moisture responsive behavior within seconds when exposed to moisture.The corresponding mechanism was studied using time-resolved attenuated total reflectance FT-IR spectroscopy in the molecular level and the water diffusion coefficient was estimated to be 1.07×10^(–8)cm^(2)∙s^(-1).Two-dimensional correlation FT-IR spectra analysis was performed to confirm that the interaction between water and polyether phase was in preference to that between water and polyamide matrix,and water molecule only forms hydrogen bond with the polyether segment.Due to the incorporation of PEO segments,the PEBAs have the surface resistivity varying from 5.6×10^(9)to 6.5×10^(10)Ω,which makes PEBA potential candidate as permanent antistatic agent.展开更多
Atmospheric CO_(2)concentrations are soaring due to the continued use of fossil fuels in energy production,an anthropogenic activity that is playing a leading role in global warming.Thus,research aimed at the capture ...Atmospheric CO_(2)concentrations are soaring due to the continued use of fossil fuels in energy production,an anthropogenic activity that is playing a leading role in global warming.Thus,research aimed at the capture and conversion of CO_(2)into value-added products,such as cyclic carbonates,is booming.While CO_(2)is an abundant,cheap,non-toxic,and readily accessible Cl feedstock,its thermodynamic stability necessitates the development of highly efficient catalysts that are able to promote chemical reactions under mild conditions.In this work,a novel mesoporous poly(ionic liquid)with dual active sites was synthesized through a facile method that involves co-polymerization,post-synthetic metalation,and supercritical CO_(2)drying.Due to a high density of nucleophilic and electrophilic sites,the as-prepared poly(ionic liquid),denoted as P2D-4BrBQA-Zn,offers excellent performance in a CO_(2)cycloaddition reaction using epichlorohydrin as the substrate(98.9%conversion and 96.9%selectivity).Moreover the reaction is carried out under mild,solvent-free,and additive-free conditions.Notably,P2D-4BrBQA-Zn also efficiently promotes the conversion of various other epoxide substrates into cyclic carbonates.Overall,the catalyst is found to have excellent substrate compatibility,stability,and recyclability.展开更多
Recently,poly(ethylene oxide)(PEO)-based solid polymer electrolytes have been attracting great attention,and efforts are currently underway to develop PEO-based composite electrolytes for next generation high performa...Recently,poly(ethylene oxide)(PEO)-based solid polymer electrolytes have been attracting great attention,and efforts are currently underway to develop PEO-based composite electrolytes for next generation high performance all-solid-state lithium metal batteries.In this article,a novel sandwich structured solid-state PEO composite electrolyte is developed for high performance all-solid-state lithium metal batteries.The PEO-based composite electrolyte is fabricated by hot-pressing PEO,LiTFSI and Ti_(3)C_(2)T_(x) MXene nanosheets into glass fiber cloth(GFC).The as-prepared GFC@PEO-MXene electrolyte shows high mechanical properties,good electrochemical stability,and high lithium-ion migration number,which indicates an obvious synergistic effect from the microscale GFC and the nanoscale MXene.Such as,the GFC@PEO-1 wt%MXene electrolyte shows a high tensile strength of 43.43 MPa and an impressive Young's modulus of 496 MPa,which are increased by 1205%and 6048%over those of PEO.Meanwhile,the ionic conductivity of GFC@PEO-1 wt%MXene at 60℃ reaches 5.01×10^(-2) S m^(-1),which is increased by around 200%compared with that of GFC@PEO electrolyte.In addition,the Li/Li symmetric battery based on GFC@PEO-1 wt%MXene electrolyte shows an excellent cycling stability over 800 h(0.3 mA cm^(-2),0.3 mAh cm^(-2)),which is obviously longer than that based on PEO and GFC@PEO electrolytes due to the better compatibility of GFC@PEO-1 wt%MXene electrolyte with Li anode.Furthermore,the solid-state Li/LiFePO_(4) battery with GFC@PEO-1 wt%MXene as electrolyte demonstrates a high capacity of 110.2–166.1 mAh g^(-1) in a wide temperature range of 25–60C,and an excellent capacity retention rate.The developed sandwich structured GFC@PEO-1 wt%MXene electrolyte with the excellent overall performance is promising for next generation high performance all-solid-state lithium metal batteries.展开更多
BACKGROUND Poly(ADP-ribose)polymerase inhibitors(PARPis)are approved as first-line therapies for breast cancer gene(BRCA)-positive,human epidermal growth factor receptor 2-negative locally advanced or metastatic breas...BACKGROUND Poly(ADP-ribose)polymerase inhibitors(PARPis)are approved as first-line therapies for breast cancer gene(BRCA)-positive,human epidermal growth factor receptor 2-negative locally advanced or metastatic breast cancer.They are also effective for new and recurrent ovarian cancers that are BRCA-or homologous recombination deficiency(HRD)-positive.However,data on these mutations and PARPi use in the Middle East are limited.AIM To assess BRCA/HRD prevalence and PARPi use in patients in the Middle East with breast/ovarian cancer.METHODS This was a single-center retrospective study of 57 of 472 breast cancer patients tested for BRCA mutations,and 25 of 65 ovarian cancer patients tested for HRD.These adult patients participated in at least four visits to the oncology service at our center between August 2021 and May 2023.Data were summarized using descriptive statistics and compared using counts and percentages.Response to treatment was assessed using Response Evaluation Criteria in Solid Tumors criteria.RESULTS Among the 472 breast cancer patients,12.1%underwent BRCA testing,and 38.5%of 65 ovarian cancer patients received HRD testing.Pathogenic mutations were found in 25.6%of the tested patients:26.3%breast cancers had germline BRCA(gBRCA)mutations and 24.0%ovarian cancers showed HRD.Notably,40.0%of gBRCA-positive breast cancers and 66.0%of HRD-positive ovarian cancers were Middle Eastern and Asian patients,respectively.PARPi treatment was used in 5(33.3%)gBRCA-positive breast cancer patients as first-line therapy(n=1;7-months progression-free),for maintenance(n=2;>15-months progression-free),or at later stages due to compliance issues(n=2).Four patients(66.6%)with HRD-positive ovarian cancer received PARPi and all remained progression-free.CONCLUSION Lower testing rates but higher BRCA mutations in breast cancer were found.Ethnicity reflected United Arab Emirates demographics,with breast cancer in Middle Eastern and ovarian cancer in Asian patients.展开更多
Polymer science encompasses a different range of materials critical to industries spanning from packaging to biomedicine. Understanding the synthesis, characterization, and applications of common homopolymers and copo...Polymer science encompasses a different range of materials critical to industries spanning from packaging to biomedicine. Understanding the synthesis, characterization, and applications of common homopolymers and copolymers is fundamental to advancing polymer research and development. In this comprehensive review, we explore various preparation methods, including free radical, anionic, and cationic polymerization, utilized for synthesizing homopolymers and copolymers. Furthermore, we investigate solvent choices commonly employed for polymer characterization, ranging from neat conditions, polar protic and polar aprotic solvents. We also explored characterization techniques, including Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR), Atomic Force Microscopy (AFM), Differential Scanning Calorimetry (DSC), and Thermogravimetric Analysis (TGA). In addition to industrial applications, we highlight the diverse biological applications of homopolymers, poly(2-hydroxyethyl methacrylate) (pHEMA) and polystyrene, which find its extensive use in biomedicine. By synthesizing and analyzing this wealth of information, this review aims to provide a comprehensive understanding of the synthesis, characterization, and applications of homopolymers and copolymers, with a particular focus on their biological applications. This holistic approach not only contributes to advancements in polymer science and technology but also fosters innovation in biomedicine, ultimately benefiting human health and well-being.展开更多
The preparation of TiO2/poly(L-lactide-co-ε-caprolactone)(PLCL) nanocomposites and their properties were reported.TiO2nanoparticles were surface modified by ring-opening polymerization of ε-caprolactone(ε-CL)...The preparation of TiO2/poly(L-lactide-co-ε-caprolactone)(PLCL) nanocomposites and their properties were reported.TiO2nanoparticles were surface modified by ring-opening polymerization of ε-caprolactone(ε-CL).The resulting poly(ε-caprolactone)-grafted TiO2(g-TiO2) was characterized by Fourier transform infrared spectroscopy(FTIR),thermogravimetric analysis(TGA) and transmission electron microscopy(TEM).The g-TiO2can be uniformly dispersed in chloroform and the g-TiO2/PLCL nanocomposites were successfully fabricated through solvent-casting method.The effects of the content of g-TiO2nanoparticles on tensile properties and shape memory properties were investigated.A significant improvement in the tensile properties of the 5% g-TiO2/PLCL mass fraction nanocomposite is obtained:an increase of 113% in the tensile strength and an increase of 11% in the elongation at break over pure PLCL polymer.The g-TiO2/PLCL nanocomposites with a certain amount of g-TiO2content have better shape memory properties than pure PLCL polymer.The g-TiO2nanoparticles play an additional physical crosslinks which are contributed to improvement of the shape memory properties.展开更多
In oil and gas field, the application of kinetic hydrate inhibitors (KHIs) independently has remained problematic in high subcooling and high water-cut situation. One feasible method to resolve this problem is the c...In oil and gas field, the application of kinetic hydrate inhibitors (KHIs) independently has remained problematic in high subcooling and high water-cut situation. One feasible method to resolve this problem is the combined use of KHIs and some synergists, which would enhance KHIs’ inhibitory effect on both hydrate nucleation and hydrate crystal growth. In this study, a novel kind of KHI copolymer poly(N-vinyl-2-pyrrolidone-co-2-vinyl pyridine)s (HGs) is used in conjunction with TBAB to show its high performance on hydrate inhibition. The performance of HGs with different monomer ratios in structure II tetrahydrofuran (THF) hydrate is investigated using kinetic hydrate inhibitor evaluation apparatus by step-cooling method and isothermal cooling method. With the combined gas hydrate inhibitor at the concentration of 1.0 wt%, the induction time of 19 wt% THF solution could be prolonged to 8.5 h at a high subcooling of 6℃. Finally, the mechanism of HGs inhibiting the formation of gas hydrate is proposed.展开更多
PANI copolymer micro/nanostructures with different surface wettability were obtained from the chemical oxidation copolymerization of aniline(Ani)with 2-ethyl aniline(EA)at diverse[EA]/[Ani+EA]molar ratios,by employing...PANI copolymer micro/nanostructures with different surface wettability were obtained from the chemical oxidation copolymerization of aniline(Ani)with 2-ethyl aniline(EA)at diverse[EA]/[Ani+EA]molar ratios,by employing ammonium persulfate as an oxidant.The results revealed that the poly(aniline-co-2-ethyl aniline)(PANI-EA)copolymer micro/nanostructures exhibited satisfactory anticorrosion performance for carbon steel,and the corrosion protection efficiency increased with the increase of water repellent property.Poly(2-ethyl aniline)(PEA)showed the largest contact angle(CA=145°)and show the best corrosion protection for the carbon steel(h=87.29%).It is found that the superior anticorrosion property of PEA is attributed to its high hydrophobicity,low conductivity and low porosity.展开更多
Comblike poly(methyl methacrylate) was synthesized by atom transfer radical polymerization of methyl methacrylate with poly(ethyl 2-bromoacrylate) as a macroinitiator, which was prepared by conventional free radical p...Comblike poly(methyl methacrylate) was synthesized by atom transfer radical polymerization of methyl methacrylate with poly(ethyl 2-bromoacrylate) as a macroinitiator, which was prepared by conventional free radical polymerization of ethyl 2-bromoacrylate. The obtained comblike polymers were characterized by GPC and 1H NMR.展开更多
Disubstituted oxazoles were prepared conveniently by treatment of aromatic -methyl ketones and nitriles with poly[styrene(iodosodiacetate)] in one-pot process.
Micro-encapsulated phase-change materials(micro PCMs) with Na_2 HPO_4·12 H_2 O encapsulated in poly(lactic acid)(PLA) shell were prepared by a solvent evaporation–precipitation method that involves the use of a ...Micro-encapsulated phase-change materials(micro PCMs) with Na_2 HPO_4·12 H_2 O encapsulated in poly(lactic acid)(PLA) shell were prepared by a solvent evaporation–precipitation method that involves the use of a coaxial needle. The effects of PLA concentration, stirring speed, injection rate of core and shell solutions, and polyvinyl alcohol(PVA) concentration on phase change properties were investigated. The thermal properties of microP CMs were characterized by differential scanning calorimetry(DSC). The capsules prepared under the optimal conditions are about 2 mm in diameter and show a latent heat of up to 122.2 J·g^(-1).展开更多
基金supported by the National Natural Scientific Foundation of China(No.21674107)the Fundamental Research Funds for the Central Universities(No.WK2340000066)the financial support from CASTWAS President’s PhD Fellowship Programme 2013
文摘A novel trifunctional initiator with one alkyne and two trifluoromethanesulfonate moieties was synthesized from a protected alcohol 5-hydroxyl-2-phenyl-1, 3-dioxane. The alkyne func- tionalized intermediate with two protected alcohol groups was synthesized by reacting with propargyl bromide. The alcohol groups were cleaved using a mixture of tetrahydrofuran and hydrochloric acid aqueous solution. In the last step the initiator was synthesized us- ing triflic anhydride in carbon tetrachloride. The initiator was characterized by 1H NMR and used for the polymerization of 2-ethyl-2-oxazoline which gives polymers with narrow distribution. For comparison a similar initiator with two tosylates was prepared and used for the polymerization of the monomer 2-ethyl-2-oxazoline, the resulting product has a wide molecular weight distribution and most of the initiator remains unreacted after 24 h which may be due to the steric hindrance between the two tosylate groups. To further explore the steric hindrance phenomenon, a linear tosylate initiator was synthesized, but still some of the initiator remains unreacted, illustrating that both steric hindrance and electrophilic balance affect the efficiency of the cationic ring-opening polymerization. All of the polymers were characterized in detail by using IH NMR, matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy, and size exclusion chromatography to confirm the purity and distribution of the polymers.
基金financially supported by the National Natural Science Foundation of China (51973215, 52025035, 52103194, 22105199, 51829302)Bureau of International Cooperation Chinese Academy of Science (121522KYSB20200029)the Youth Innovation Promotion Association of Chinese Academy of Sciences (2020232)
文摘Poly(2-oxazoline)(POx)has been regarded as a potential candidate for drug delivery carrier to meet the challenges of nanomedicine clinical translation,due to its excellent biocompatibility and self-assembly properties.The drug loading capacity and stability of amphiphilic POxs as drug nanocarriers,however,tend to be insufficient.Herein,we report a strategy to prepare nucleobase-crosslinked POx nanoparticles(NPs)with enhanced stability and ultra-high paclitaxel(PTX)loading capacity for breast cancer therapy.An amphiphilic amine-functionalized POx(PMBEOx-NH_(2))was firstly prepared through a click reaction between cysteamines and vinyl groups in poly(2-methyl-2-oxazoline)-block-poly(2–butyl–2-oxazoline-co-2-butenyl-2-oxazoline)(PMBEOx).Complementary nucleobase-pairs adenine(A)and uracil(U)were subsequently conjugated to PMBEOx-NH2 to give functional POxs(POxA and POxU),respectively.Due to the nucleobase interactions formed between A and U,NPs formed by POxA and POxU at a molar ratio of 1:1 displayed ultrahigh PTX loading capacity(38.2%,PTX/POxA@U),excellent stability,and reduced particle size compared to the uncross-linked PTX-loaded NPs(PTX/PMBEOx).Besides the prolonged blood circulation and enhanced tumor accumulation,the smaller PTX/POxA@U NPs also have better tumor penetration ability compared with PTX/PMBEOx,thus leading to a higher tumor suppression rate in two murine breast cancer models(E0711 and 4T1).These results proved that the therapeutic effect of chemotherapeutic drugs could be improved remarkably through a reasonable optimization of nanocarriers.
基金supported by National Natural Science Foundation of China (81102394)Natural Science Foundation of Liaoning Province (20170540575)
文摘This study aimed to investigate the ability of the novel materials D-α-tocopheryl poly(2-ethyl-2-oxazoline) succinate(TPOS) to construct pH-sensitive liposomes. TPOS was initially synthesized and characterized by TLC, FTIR, and ~1H-NMR. The buffering capacity of polyethylene glycol-distearoyl phosphatidylethanolamine(PEG-DSPE) and TPOS was determined by acid-base titration, and TPOS displayed a slower downtrend and gentler slope of titration curve than PEG-DSPE within pH 7.4–5.0. Studies on the in vitro drug release demonstrated that TPOS modified docetaxel(DOC) liposomes(TPOS-DOC-L) had a slower drugrelease rate at pH 7.4 similar to PEGylated-DOC liposomes(PEG-DOC-L), whereas the release rate reached approximately 86.92% ± 1.69% at pH 6.4. In vitro cellular uptake assays by microplate reader, and flow cytometry revealed that TPOS modified coumarin 6 liposomes(TPOS-C6-L) had stronger cellular uptake at pH 6.4 than that at pH 7.4( P < 0.01). Conversely, for PEGylated C6 liposomes(PEG-C6-L) and conventional C6 liposomes(C6-L), very similar cellular uptakes were exhibited at different pH values. Confocal laser scanning microscopy images showed that PEG-C6-L and C6-L were mainly located in lysosomes. By contrast, TPOS-C6-L showed broader cytoplasmic release and distribution at 4 h. MTT assay showed that the cytotoxicity of TPOS-DOC-L was similar to that of PEG-DOC-L and conventional DOC liposomes(DOC-L) at the same DOC concentration and at pH 7.4, but was much lower than those at pH 6.4 after 48 h of incubation. The apoptosis of PEG-DOC-L and DOC-L had no remarkable improvement with decreased pH from 7.4 to 6.4. Meanwhile, TPOS-DOC-Lsignificantly induced the apoptosis of HeLa cells with decreased pH. Therefore, TPOS can be a biomaterial for the construction of a pH-sensitive drug delivery system.
基金Supported by the National Natural Science Foundation of China(Grant no.59503002)and Polymer Physics Laboratory of Changchun Institute of Applied Chemistry,Chinese Academy of Sciences
文摘By mechanism-transformation (anionic --> cationic) poly(styrene-6-2-ethyl-2-oxazoline) diblock copolymer, PS-b-PEOx, was synthesized in two steps. The first step is the polymerization of styrene block capped with ethylene oxide and its tosylation; the second step is the cationic ring-opening polymerization of 2-ethyl-2-oxazoline. The products were thoroughly characterized by various methods, such as H-1-NMR, IR, DMA, TEM and SAXS. The results show that the copolymer obtained possesses high molecular weight and narrow molecular weight distribution.
基金financially supported by the National Natural Science Foundation of China (21978089 and 21878256)the Fundamental Research Funds for the Central Universities (22221818010)+1 种基金the 111 Project (B20031)the Program of Shanghai Subject Chief Scientist (21XD1433000)
文摘Functional multiblock poly(ether-b-amide)(PEBA)copolymers,comprised of PA1212(polyamide 1212)as hard segments and Jeffamine ED-2003 as soft segments,were successfully prepared via two-step melt polycondensation without any amidation catalyst.Here,using diamino-terminated poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide)(PPO-PEO-PPO),Jeffamine ED-2003,enhances the compatibility between polyamide oligomer and polyether,which is better than the traditional route using hydroxyl-terminated polyether.The chemical structure of multiblock PEBAs,as well as the microphase separated structure with crystalline phase of polyamide and polyether,were confirmed by heteronuclear multiple-bond correlation spectrum,heteronuclear multiple quantum correlation spectrum,Fourier transform infrared spectroscopy(FT-IR),differential scanning calorimetry and dynamic mechanical analysis.The hydrophilic PEBA copolymers showed water adsorption ranging from 87.3%to 17.1%depending on the polyether content,and specially showed moisture responsive behavior within seconds when exposed to moisture.The corresponding mechanism was studied using time-resolved attenuated total reflectance FT-IR spectroscopy in the molecular level and the water diffusion coefficient was estimated to be 1.07×10^(–8)cm^(2)∙s^(-1).Two-dimensional correlation FT-IR spectra analysis was performed to confirm that the interaction between water and polyether phase was in preference to that between water and polyamide matrix,and water molecule only forms hydrogen bond with the polyether segment.Due to the incorporation of PEO segments,the PEBAs have the surface resistivity varying from 5.6×10^(9)to 6.5×10^(10)Ω,which makes PEBA potential candidate as permanent antistatic agent.
基金financial support from the National Natural Science Foundation of China(22078274,21903066)。
文摘Atmospheric CO_(2)concentrations are soaring due to the continued use of fossil fuels in energy production,an anthropogenic activity that is playing a leading role in global warming.Thus,research aimed at the capture and conversion of CO_(2)into value-added products,such as cyclic carbonates,is booming.While CO_(2)is an abundant,cheap,non-toxic,and readily accessible Cl feedstock,its thermodynamic stability necessitates the development of highly efficient catalysts that are able to promote chemical reactions under mild conditions.In this work,a novel mesoporous poly(ionic liquid)with dual active sites was synthesized through a facile method that involves co-polymerization,post-synthetic metalation,and supercritical CO_(2)drying.Due to a high density of nucleophilic and electrophilic sites,the as-prepared poly(ionic liquid),denoted as P2D-4BrBQA-Zn,offers excellent performance in a CO_(2)cycloaddition reaction using epichlorohydrin as the substrate(98.9%conversion and 96.9%selectivity).Moreover the reaction is carried out under mild,solvent-free,and additive-free conditions.Notably,P2D-4BrBQA-Zn also efficiently promotes the conversion of various other epoxide substrates into cyclic carbonates.Overall,the catalyst is found to have excellent substrate compatibility,stability,and recyclability.
基金support of the Fundamental Research Funds for the Central Universities(No.2022CDJQY-004)the Fund for Innovative Research Groups of Natural Science Foundation of Hebei Province(No.A2020202002).
文摘Recently,poly(ethylene oxide)(PEO)-based solid polymer electrolytes have been attracting great attention,and efforts are currently underway to develop PEO-based composite electrolytes for next generation high performance all-solid-state lithium metal batteries.In this article,a novel sandwich structured solid-state PEO composite electrolyte is developed for high performance all-solid-state lithium metal batteries.The PEO-based composite electrolyte is fabricated by hot-pressing PEO,LiTFSI and Ti_(3)C_(2)T_(x) MXene nanosheets into glass fiber cloth(GFC).The as-prepared GFC@PEO-MXene electrolyte shows high mechanical properties,good electrochemical stability,and high lithium-ion migration number,which indicates an obvious synergistic effect from the microscale GFC and the nanoscale MXene.Such as,the GFC@PEO-1 wt%MXene electrolyte shows a high tensile strength of 43.43 MPa and an impressive Young's modulus of 496 MPa,which are increased by 1205%and 6048%over those of PEO.Meanwhile,the ionic conductivity of GFC@PEO-1 wt%MXene at 60℃ reaches 5.01×10^(-2) S m^(-1),which is increased by around 200%compared with that of GFC@PEO electrolyte.In addition,the Li/Li symmetric battery based on GFC@PEO-1 wt%MXene electrolyte shows an excellent cycling stability over 800 h(0.3 mA cm^(-2),0.3 mAh cm^(-2)),which is obviously longer than that based on PEO and GFC@PEO electrolytes due to the better compatibility of GFC@PEO-1 wt%MXene electrolyte with Li anode.Furthermore,the solid-state Li/LiFePO_(4) battery with GFC@PEO-1 wt%MXene as electrolyte demonstrates a high capacity of 110.2–166.1 mAh g^(-1) in a wide temperature range of 25–60C,and an excellent capacity retention rate.The developed sandwich structured GFC@PEO-1 wt%MXene electrolyte with the excellent overall performance is promising for next generation high performance all-solid-state lithium metal batteries.
文摘BACKGROUND Poly(ADP-ribose)polymerase inhibitors(PARPis)are approved as first-line therapies for breast cancer gene(BRCA)-positive,human epidermal growth factor receptor 2-negative locally advanced or metastatic breast cancer.They are also effective for new and recurrent ovarian cancers that are BRCA-or homologous recombination deficiency(HRD)-positive.However,data on these mutations and PARPi use in the Middle East are limited.AIM To assess BRCA/HRD prevalence and PARPi use in patients in the Middle East with breast/ovarian cancer.METHODS This was a single-center retrospective study of 57 of 472 breast cancer patients tested for BRCA mutations,and 25 of 65 ovarian cancer patients tested for HRD.These adult patients participated in at least four visits to the oncology service at our center between August 2021 and May 2023.Data were summarized using descriptive statistics and compared using counts and percentages.Response to treatment was assessed using Response Evaluation Criteria in Solid Tumors criteria.RESULTS Among the 472 breast cancer patients,12.1%underwent BRCA testing,and 38.5%of 65 ovarian cancer patients received HRD testing.Pathogenic mutations were found in 25.6%of the tested patients:26.3%breast cancers had germline BRCA(gBRCA)mutations and 24.0%ovarian cancers showed HRD.Notably,40.0%of gBRCA-positive breast cancers and 66.0%of HRD-positive ovarian cancers were Middle Eastern and Asian patients,respectively.PARPi treatment was used in 5(33.3%)gBRCA-positive breast cancer patients as first-line therapy(n=1;7-months progression-free),for maintenance(n=2;>15-months progression-free),or at later stages due to compliance issues(n=2).Four patients(66.6%)with HRD-positive ovarian cancer received PARPi and all remained progression-free.CONCLUSION Lower testing rates but higher BRCA mutations in breast cancer were found.Ethnicity reflected United Arab Emirates demographics,with breast cancer in Middle Eastern and ovarian cancer in Asian patients.
文摘Polymer science encompasses a different range of materials critical to industries spanning from packaging to biomedicine. Understanding the synthesis, characterization, and applications of common homopolymers and copolymers is fundamental to advancing polymer research and development. In this comprehensive review, we explore various preparation methods, including free radical, anionic, and cationic polymerization, utilized for synthesizing homopolymers and copolymers. Furthermore, we investigate solvent choices commonly employed for polymer characterization, ranging from neat conditions, polar protic and polar aprotic solvents. We also explored characterization techniques, including Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR), Atomic Force Microscopy (AFM), Differential Scanning Calorimetry (DSC), and Thermogravimetric Analysis (TGA). In addition to industrial applications, we highlight the diverse biological applications of homopolymers, poly(2-hydroxyethyl methacrylate) (pHEMA) and polystyrene, which find its extensive use in biomedicine. By synthesizing and analyzing this wealth of information, this review aims to provide a comprehensive understanding of the synthesis, characterization, and applications of homopolymers and copolymers, with a particular focus on their biological applications. This holistic approach not only contributes to advancements in polymer science and technology but also fosters innovation in biomedicine, ultimately benefiting human health and well-being.
基金Project(50903023) supported by the National Natural Science Foundation of ChinaProject(HEUCF201210005) supported by the Fundamental Research Funds for the Central Universities,ChinaProject(2010RFQXG037) supported by Harbin Special Fund for Innovation Talents of Science and Technology,China
文摘The preparation of TiO2/poly(L-lactide-co-ε-caprolactone)(PLCL) nanocomposites and their properties were reported.TiO2nanoparticles were surface modified by ring-opening polymerization of ε-caprolactone(ε-CL).The resulting poly(ε-caprolactone)-grafted TiO2(g-TiO2) was characterized by Fourier transform infrared spectroscopy(FTIR),thermogravimetric analysis(TGA) and transmission electron microscopy(TEM).The g-TiO2can be uniformly dispersed in chloroform and the g-TiO2/PLCL nanocomposites were successfully fabricated through solvent-casting method.The effects of the content of g-TiO2nanoparticles on tensile properties and shape memory properties were investigated.A significant improvement in the tensile properties of the 5% g-TiO2/PLCL mass fraction nanocomposite is obtained:an increase of 113% in the tensile strength and an increase of 11% in the elongation at break over pure PLCL polymer.The g-TiO2/PLCL nanocomposites with a certain amount of g-TiO2content have better shape memory properties than pure PLCL polymer.The g-TiO2nanoparticles play an additional physical crosslinks which are contributed to improvement of the shape memory properties.
基金supported by the National Basic Research Program of China ("973" Program) (Grant No. 2009CB219504-03)the National Natural Science Foundation of China (Grant No 51106054)the Colleges and Universities High-level Talents Program of Guangdong
文摘In oil and gas field, the application of kinetic hydrate inhibitors (KHIs) independently has remained problematic in high subcooling and high water-cut situation. One feasible method to resolve this problem is the combined use of KHIs and some synergists, which would enhance KHIs’ inhibitory effect on both hydrate nucleation and hydrate crystal growth. In this study, a novel kind of KHI copolymer poly(N-vinyl-2-pyrrolidone-co-2-vinyl pyridine)s (HGs) is used in conjunction with TBAB to show its high performance on hydrate inhibition. The performance of HGs with different monomer ratios in structure II tetrahydrofuran (THF) hydrate is investigated using kinetic hydrate inhibitor evaluation apparatus by step-cooling method and isothermal cooling method. With the combined gas hydrate inhibitor at the concentration of 1.0 wt%, the induction time of 19 wt% THF solution could be prolonged to 8.5 h at a high subcooling of 6℃. Finally, the mechanism of HGs inhibiting the formation of gas hydrate is proposed.
基金financial supports of the National Natural Science Foundation of China (No. 41476059)the Natural Science Foundation of Hebei Province (No. E2018108011)
文摘PANI copolymer micro/nanostructures with different surface wettability were obtained from the chemical oxidation copolymerization of aniline(Ani)with 2-ethyl aniline(EA)at diverse[EA]/[Ani+EA]molar ratios,by employing ammonium persulfate as an oxidant.The results revealed that the poly(aniline-co-2-ethyl aniline)(PANI-EA)copolymer micro/nanostructures exhibited satisfactory anticorrosion performance for carbon steel,and the corrosion protection efficiency increased with the increase of water repellent property.Poly(2-ethyl aniline)(PEA)showed the largest contact angle(CA=145°)and show the best corrosion protection for the carbon steel(h=87.29%).It is found that the superior anticorrosion property of PEA is attributed to its high hydrophobicity,low conductivity and low porosity.
文摘Comblike poly(methyl methacrylate) was synthesized by atom transfer radical polymerization of methyl methacrylate with poly(ethyl 2-bromoacrylate) as a macroinitiator, which was prepared by conventional free radical polymerization of ethyl 2-bromoacrylate. The obtained comblike polymers were characterized by GPC and 1H NMR.
文摘Disubstituted oxazoles were prepared conveniently by treatment of aromatic -methyl ketones and nitriles with poly[styrene(iodosodiacetate)] in one-pot process.
基金Supported by the National Natural Science Foundation of China(21476065)the China National Tobacco Corporation
文摘Micro-encapsulated phase-change materials(micro PCMs) with Na_2 HPO_4·12 H_2 O encapsulated in poly(lactic acid)(PLA) shell were prepared by a solvent evaporation–precipitation method that involves the use of a coaxial needle. The effects of PLA concentration, stirring speed, injection rate of core and shell solutions, and polyvinyl alcohol(PVA) concentration on phase change properties were investigated. The thermal properties of microP CMs were characterized by differential scanning calorimetry(DSC). The capsules prepared under the optimal conditions are about 2 mm in diameter and show a latent heat of up to 122.2 J·g^(-1).