Nosocomial infections affect implanted medical devices and greatly challenge their functional outcomes,becoming sometimes life threatening for the patients.Therefore,aggressive antibiotic therapies are administered,wh...Nosocomial infections affect implanted medical devices and greatly challenge their functional outcomes,becoming sometimes life threatening for the patients.Therefore,aggressive antibiotic therapies are administered,which often require the use of last-resort drugs,if the infection is caused by multi-drug-resistant bacteria.Reducing the risk of bacterial contamination of medical devices in the hospitals has thus become an emerging issue.Promising routes to control these infections are based on materials provided with intrinsic bactericidal properties(i.e.,chemical action)and on the design of surface coatings able to limit bacteria adhesion and fouling phenomena(i.e.,physical action),thus preventing bacterial biofilm formation.Here,we report the development and validation of coatings made of layer-by-layer deposition of electrospun poly(vinylidene fluoride-co-trifluoro ethylene)P(VDF-TrFE)fibers with controlled orientations,which ultimately gave rise to antifouling surfaces.The obtained 10-layer surface morphology with 90°orientation fibers was able to efficiently prevent the adhesion of bacteria,by establishing a superhydrophobic-like behavior compatible with the Cassie-Baxter regimen.Moreover,the results highlighted that surface wettability and bacteria adhesion could be controlled using fibers with diameter comparable to bacteria size(i.e.,achievable via electrospinning process),by tuning the intra-fiber spacing,with relevant implications in the future design of biomedical surface coatings.展开更多
Poly（d,l-lactide-co-p-dioxanone） （P（LA-co-PDO）） copolymers with different chain microstructures were synthesized by onestep or two-step bulk ring-opening polymerizations of d,l-lactide （LA） and p-dioxanone （...Poly（d,l-lactide-co-p-dioxanone） （P（LA-co-PDO）） copolymers with different chain microstructures were synthesized by onestep or two-step bulk ring-opening polymerizations of d,l-lactide （LA） and p-dioxanone （PDO） monomers using stannous octoate [Sn（Oct）2]/n-dodecanol as the initiating system. The average sequence lengths of the lactidyl （LLA） and dioxanyl （LpDo） units were calculated from the ^1H NMR spectra. It was found that both LLA and Lpoo values from the two-step syntheses were significantly longer than those from the corresponding one-step syntheses, indicating more blocky structure achieved for the twostep copolymers. Corresponding to this difference in microstructure, the two-step copolymers were semi-crystalline, while the one-step copolymers were completely amorphous. In conclusion, the crystallinity of P（LA-co-PDO） copolymers could be adjusted conveniently to meet specific applications by changing the microstructure of the copolymers via different polymerization routes.展开更多
Integrating poly（lactic acid） （PLA）, glycolic acid （GA） and ethylene glycol （EG） will hopefully result in a novel copolymer that combines such advantages as fastened and controllable release rate and improved ...Integrating poly（lactic acid） （PLA）, glycolic acid （GA） and ethylene glycol （EG） will hopefully result in a novel copolymer that combines such advantages as fastened and controllable release rate and improved flexibility together with good biocompatibility. In this study, p-dioxanone （PDO） was employed to copolymerize with DL-lactide （LA） via ring-opening melt polymerization using Sn（Oct）2 as an initiator and ethylene glycol as a co-initiator. The obtained degradable macrodiols （HO-P（LA-co-PDO）-OH） were just such a copolymer consisting of PLA, GA and EG. 1HNMR was employed to characterize the copolymers, and the effect of PDO/LA molar ratios in the feedstock on the molecular weights of HO-P（LA-co-PDO）-OH was investigated by means of endhydroxyl analysis, 1H NMR or GPC-MALLs. The results confirmed the successful synthesis of HO-P（LA-co-PDO）-OH and revealed that one end-hydroxyl of the micarodiols was donated by LA or PDO and the other one by the co-initiator EG. In addition, the molecular weights of HO-P（LA-co-PDO）-OH increased with decreasing PDO/LA ratios.展开更多
Novel amphiphilic triblock copolymer poly（p-dioxanone-co-5-benzyloxytrimethylene carbonate）-block-poly（ethylene glycol）-block-poly（p-dioxanone-co-5-benzyloxytrimethylene carbonate） （p（PDO-co-BTMC）-b-PEG-b-p（...Novel amphiphilic triblock copolymer poly（p-dioxanone-co-5-benzyloxytrimethylene carbonate）-block-poly（ethylene glycol）-block-poly（p-dioxanone-co-5-benzyloxytrimethylene carbonate） （p（PDO-co-BTMC）-b-PEG-b-p（PDO-co-BTMC）） was successfully synthesized using immobilized porcine pancreas lipase on porous silica particles （IPPL） as the catalyst for the fLrSt time. 1H NMR, 13C NMR and GPC analysis were used to confirm the structures of resulting copolymers. The molecular weight （Mn） of the copolymer with feed ratio of 69：20：11 （BTMC： PDO： PEG ） was 31300 g/mol and the polydispersity was 1.85, while the Mn decreased to 25000 g/mol and polydispersity of 1.93 with the feed ratio of 50：40：10.展开更多
To determine the possibility of blending 2, 3, 5-triiodobenzoic acid( TIBA) and poly( p-dioxanone)( PPDO) to produce X-ray visible PPDO filaments,melt-blended PPDO with different concentrations of TIBA was obtained. S...To determine the possibility of blending 2, 3, 5-triiodobenzoic acid( TIBA) and poly( p-dioxanone)( PPDO) to produce X-ray visible PPDO filaments,melt-blended PPDO with different concentrations of TIBA was obtained. Several radiopaque filaments of PPDO polymer filled with radiopaque TIBA particles were prepared via melt-blending. Material properties of the composite filaments were investigated using various material characterization techniques,including scanning electron microscope( SEM),thermogravimetric analysis( TGA),X-ray Diffraction( XRD),dynamic rheometry and micro-CT scan. In this article,the dispersion of TIBA in PPDO,the properties of the filament,and the ratio of PPDO and TIBA and the corresponding X-ray visibility in vivo were studied. SEM results showed the dispersion of the contrast imaging agent TIBA was relatively even in the PPDO polymer. Xray analysis in vitro confirmed the enhanced radiopacity of the filaments with respect to the pure PPDO filament. The presence of iodine element in the composite filament could allow the bioabsorbable material to be monitored in vivo, and made it potential to be used in biomedical applications.展开更多
In this paper, poly （acrylamide-co-acrylic acid） （P（AM-co-AA）） hydrogel was pre- pared in an aqueous solution by using glow-discharge electrolysis plasma （GDEP） induced copoly- merization of acrylamide （AM） ...In this paper, poly （acrylamide-co-acrylic acid） （P（AM-co-AA）） hydrogel was pre- pared in an aqueous solution by using glow-discharge electrolysis plasma （GDEP） induced copoly- merization of acrylamide （AM） and acrylic acid （AA）, in which N,N＇-methylenebisacrylamide （MBA） was used as a crosslinker. A mechanism for the synthesis of P（AM-co-AA） hydrogel was proposed. To optimize the synthesis condition, the following parameters were examined in detail： the discharge voltage, discharge time, the content of the crosslinker, and the mass ratio of AM to AA. The results showed that the optimum pH range for cationic dyes removal was found to be 5.0-10.0. The P（AM-co-AA） hydrogel exhibits a very high adsorption potential and the ex- perimental adsorption capacities for Crystal violet （CV） and Methylene blue （MB） were 2974.3 mg/g and 2303.6 mg/g, respectively. The adsorption process follows a pseudo-second-order kinetic model. In addition, the adsorption mechanism of P（AM-co-AA） hydrogel for cationic dyes was also discussed.展开更多
Two polymeric adsorbents, poly(methyl p-vinylbenzyl ether) and poly(phenyl p-vinylbenzyl ether), were synthesized from chloromethylated polystyrene. Their adsorption property for phenol in hexane solution was investig...Two polymeric adsorbents, poly(methyl p-vinylbenzyl ether) and poly(phenyl p-vinylbenzyl ether), were synthesized from chloromethylated polystyrene. Their adsorption property for phenol in hexane solution was investigated. The results showed that the two adsorbents adsorb phenol from hexane solution through hydrogen-bonding and π-π stacking interaction.展开更多
Two crosslinkable poly（p-phenyleneethynylene）s（PPEs）： poly[2,5-di（2＇-ethyl-hexyloxy）-1,4-phenylenecthynylene] with end-capped vinyl（PPE1） and poly[2,5-di（allyloxy）-1,4-phenyleneethynylene-2,5-di（2＇-ethyl...Two crosslinkable poly（p-phenyleneethynylene）s（PPEs）： poly[2,5-di（2＇-ethyl-hexyloxy）-1,4-phenylenecthynylene] with end-capped vinyl（PPE1） and poly[2,5-di（allyloxy）-1,4-phenyleneethynylene-2,5-di（2＇-ethyl-hexyloxy）-1,4-phenyleneethynylene]（PPE2） were synthesized. Via the thermal addition reactions of vinyl end groups of PPE1 and allyloxy side groups of PPE2, crosslinked polymers C-PPE1 and C-PPE2 were obtained, respectively. The two polymers were characterized by wide-angle X-ray diffraction（WXRD）, ultraviolet-visible（UV-Vis） absorption, and photoluminescence（PL）. The results indicate that in the solid state, the polymer chains of PPE1 were packed with a low degree of crystallinity because of the sterically hindered（2＇-ethyl-hexyl）oxy branched side chains, but, because of the introduction of allyloxy side chains, the polymer chains of PPE2 were packed in an order fashion with a high degree of crystallinity. Because of the high crosslinking density in C-PPE2, the formation of aggregates and excimer was hampered by the formed crosslinking network more effectively in C-PPE2 film than in C-PPE1 film.展开更多
The morphology and crytal structure of poly(p-phenylene terephthalate) (PPT), prepared by confined thin filmmelt (CTFMP) and solution (CTFSP) and bulk solution polymerization, were characterized by transmission electr...The morphology and crytal structure of poly(p-phenylene terephthalate) (PPT), prepared by confined thin filmmelt (CTFMP) and solution (CTFSP) and bulk solution polymerization, were characterized by transmission electronmicroscopy, electron dimaction and molecular modeling. The unit cell is monoclinic (P2_1/a space group) with parameters a =7.89, b = 5.49, c = 12.65 A, α=γ= 90°, β=100.33°, density = 1.48 g/cm^3, the a, b and β values differing slightly from thosereported previously in the literature. A degree of variation in relative intensities of hk0 reflections in, apparently, untilted[001] ED patterns was observed from a given sample, suggesting some variation in molecular packing. ED evidence wasfound for a second phase, with [001] appearing the same as for phase Ⅱ of the related poly(p-oxybenzoate) (PpOBA)polymer. CTFMP crystals polymerized above 220℃ (up to 370℃) and CTFSP crystals polymerized at 300℃ consisted oflamellae 100-200 A thick.展开更多
Polymeric β-cyclodextrin (β-CD) supported by crosslinked poly(acrylamide-co-vinylamine) was synthesized as anartificial analog of hydrolytic enzyme and its catalysis of the hydrolysis of p-nitrophenyl acetate (p-NPA...Polymeric β-cyclodextrin (β-CD) supported by crosslinked poly(acrylamide-co-vinylamine) was synthesized as anartificial analog of hydrolytic enzyme and its catalysis of the hydrolysis of p-nitrophenyl acetate (p-NPA) was theninvestigated. The result showed that the polymer-supported β-CD could accelerate the hydrolytic reaction of p-NPA morequickly than β-CD itself and crosslinked poly(acrylamide-co-vinylamine) alone. The acceleration rate of the polymer-supported β-CD was about 10 times as fast as that of free β-CD in 0.01 mol/L phosphate buffer (pH 7.4) containing 32%DMSO at 37±0.1℃ when the molar amount of β-CD units in the polymer was equal to that of free β-CD in the experiments.The enhanced acceleration of thc polymer-supported β-CD should be ascribed to the cooperative contribution of theinclusion effect of β-CD ring and the nucleophilic effect of amino groups on the polymeric support.展开更多
文摘Nosocomial infections affect implanted medical devices and greatly challenge their functional outcomes,becoming sometimes life threatening for the patients.Therefore,aggressive antibiotic therapies are administered,which often require the use of last-resort drugs,if the infection is caused by multi-drug-resistant bacteria.Reducing the risk of bacterial contamination of medical devices in the hospitals has thus become an emerging issue.Promising routes to control these infections are based on materials provided with intrinsic bactericidal properties(i.e.,chemical action)and on the design of surface coatings able to limit bacteria adhesion and fouling phenomena(i.e.,physical action),thus preventing bacterial biofilm formation.Here,we report the development and validation of coatings made of layer-by-layer deposition of electrospun poly(vinylidene fluoride-co-trifluoro ethylene)P(VDF-TrFE)fibers with controlled orientations,which ultimately gave rise to antifouling surfaces.The obtained 10-layer surface morphology with 90°orientation fibers was able to efficiently prevent the adhesion of bacteria,by establishing a superhydrophobic-like behavior compatible with the Cassie-Baxter regimen.Moreover,the results highlighted that surface wettability and bacteria adhesion could be controlled using fibers with diameter comparable to bacteria size(i.e.,achievable via electrospinning process),by tuning the intra-fiber spacing,with relevant implications in the future design of biomedical surface coatings.
基金supported by the National Natural Sciences Fund of China(No.50603025)the Opening Project of State Key Laboratory of Polymer Materials Engineering(Sichuan University).
文摘Poly（d,l-lactide-co-p-dioxanone） （P（LA-co-PDO）） copolymers with different chain microstructures were synthesized by onestep or two-step bulk ring-opening polymerizations of d,l-lactide （LA） and p-dioxanone （PDO） monomers using stannous octoate [Sn（Oct）2]/n-dodecanol as the initiating system. The average sequence lengths of the lactidyl （LLA） and dioxanyl （LpDo） units were calculated from the ^1H NMR spectra. It was found that both LLA and Lpoo values from the two-step syntheses were significantly longer than those from the corresponding one-step syntheses, indicating more blocky structure achieved for the twostep copolymers. Corresponding to this difference in microstructure, the two-step copolymers were semi-crystalline, while the one-step copolymers were completely amorphous. In conclusion, the crystallinity of P（LA-co-PDO） copolymers could be adjusted conveniently to meet specific applications by changing the microstructure of the copolymers via different polymerization routes.
基金supported by the National Key Technologies R&D Program of China(No.2006BA103B04)the Natural Key Scientific and Technological Project of Chongqing(No.CSTC 2008AB0027)
文摘Integrating poly（lactic acid） （PLA）, glycolic acid （GA） and ethylene glycol （EG） will hopefully result in a novel copolymer that combines such advantages as fastened and controllable release rate and improved flexibility together with good biocompatibility. In this study, p-dioxanone （PDO） was employed to copolymerize with DL-lactide （LA） via ring-opening melt polymerization using Sn（Oct）2 as an initiator and ethylene glycol as a co-initiator. The obtained degradable macrodiols （HO-P（LA-co-PDO）-OH） were just such a copolymer consisting of PLA, GA and EG. 1HNMR was employed to characterize the copolymers, and the effect of PDO/LA molar ratios in the feedstock on the molecular weights of HO-P（LA-co-PDO）-OH was investigated by means of endhydroxyl analysis, 1H NMR or GPC-MALLs. The results confirmed the successful synthesis of HO-P（LA-co-PDO）-OH and revealed that one end-hydroxyl of the micarodiols was donated by LA or PDO and the other one by the co-initiator EG. In addition, the molecular weights of HO-P（LA-co-PDO）-OH increased with decreasing PDO/LA ratios.
基金the financial support of the National Natural Science Foundation of China(No.20104005).
文摘Novel amphiphilic triblock copolymer poly（p-dioxanone-co-5-benzyloxytrimethylene carbonate）-block-poly（ethylene glycol）-block-poly（p-dioxanone-co-5-benzyloxytrimethylene carbonate） （p（PDO-co-BTMC）-b-PEG-b-p（PDO-co-BTMC）） was successfully synthesized using immobilized porcine pancreas lipase on porous silica particles （IPPL） as the catalyst for the fLrSt time. 1H NMR, 13C NMR and GPC analysis were used to confirm the structures of resulting copolymers. The molecular weight （Mn） of the copolymer with feed ratio of 69：20：11 （BTMC： PDO： PEG ） was 31300 g/mol and the polydispersity was 1.85, while the Mn decreased to 25000 g/mol and polydispersity of 1.93 with the feed ratio of 50：40：10.
基金Biomedical Textile Materials Science and Technolgy(111 Project),China(No.B07024)the Fundamendtal Research funds for the Central Universities,China(Samples 2232015A3-02,16D 110119)+1 种基金Science and Technology Support Program of Shanghai,China(No.16441903803)National Postdoctoral Foundation,China(No.2016M590299)
文摘To determine the possibility of blending 2, 3, 5-triiodobenzoic acid( TIBA) and poly( p-dioxanone)( PPDO) to produce X-ray visible PPDO filaments,melt-blended PPDO with different concentrations of TIBA was obtained. Several radiopaque filaments of PPDO polymer filled with radiopaque TIBA particles were prepared via melt-blending. Material properties of the composite filaments were investigated using various material characterization techniques,including scanning electron microscope( SEM),thermogravimetric analysis( TGA),X-ray Diffraction( XRD),dynamic rheometry and micro-CT scan. In this article,the dispersion of TIBA in PPDO,the properties of the filament,and the ratio of PPDO and TIBA and the corresponding X-ray visibility in vivo were studied. SEM results showed the dispersion of the contrast imaging agent TIBA was relatively even in the PPDO polymer. Xray analysis in vitro confirmed the enhanced radiopacity of the filaments with respect to the pure PPDO filament. The presence of iodine element in the composite filament could allow the bioabsorbable material to be monitored in vivo, and made it potential to be used in biomedical applications.
基金supported by National Natural Science Foundation of China(No.21367023)Natural Science Foundation of Gansu Province,China(No.1208RJZA161)Key Project of Young Teachers’ Scientific Research Promotion of Northwest Normal University of China(Nos.NWNU-LKQN-10-16 and NWNU-LKQN-12-9)
文摘In this paper, poly （acrylamide-co-acrylic acid） （P（AM-co-AA）） hydrogel was pre- pared in an aqueous solution by using glow-discharge electrolysis plasma （GDEP） induced copoly- merization of acrylamide （AM） and acrylic acid （AA）, in which N,N＇-methylenebisacrylamide （MBA） was used as a crosslinker. A mechanism for the synthesis of P（AM-co-AA） hydrogel was proposed. To optimize the synthesis condition, the following parameters were examined in detail： the discharge voltage, discharge time, the content of the crosslinker, and the mass ratio of AM to AA. The results showed that the optimum pH range for cationic dyes removal was found to be 5.0-10.0. The P（AM-co-AA） hydrogel exhibits a very high adsorption potential and the ex- perimental adsorption capacities for Crystal violet （CV） and Methylene blue （MB） were 2974.3 mg/g and 2303.6 mg/g, respectively. The adsorption process follows a pseudo-second-order kinetic model. In addition, the adsorption mechanism of P（AM-co-AA） hydrogel for cationic dyes was also discussed.
基金the National Natural Science Foundation of China(No.29974015)the Visiting Scholar Foundation of Key Lab.In University for the financial support
文摘Two polymeric adsorbents, poly(methyl p-vinylbenzyl ether) and poly(phenyl p-vinylbenzyl ether), were synthesized from chloromethylated polystyrene. Their adsorption property for phenol in hexane solution was investigated. The results showed that the two adsorbents adsorb phenol from hexane solution through hydrogen-bonding and π-π stacking interaction.
基金Supported by the National Natural Science Foundation of China(Nos.20771030 and 20671025)
文摘Two crosslinkable poly（p-phenyleneethynylene）s（PPEs）： poly[2,5-di（2＇-ethyl-hexyloxy）-1,4-phenylenecthynylene] with end-capped vinyl（PPE1） and poly[2,5-di（allyloxy）-1,4-phenyleneethynylene-2,5-di（2＇-ethyl-hexyloxy）-1,4-phenyleneethynylene]（PPE2） were synthesized. Via the thermal addition reactions of vinyl end groups of PPE1 and allyloxy side groups of PPE2, crosslinked polymers C-PPE1 and C-PPE2 were obtained, respectively. The two polymers were characterized by wide-angle X-ray diffraction（WXRD）, ultraviolet-visible（UV-Vis） absorption, and photoluminescence（PL）. The results indicate that in the solid state, the polymer chains of PPE1 were packed with a low degree of crystallinity because of the sterically hindered（2＇-ethyl-hexyl）oxy branched side chains, but, because of the introduction of allyloxy side chains, the polymer chains of PPE2 were packed in an order fashion with a high degree of crystallinity. Because of the high crosslinking density in C-PPE2, the formation of aggregates and excimer was hampered by the formed crosslinking network more effectively in C-PPE2 film than in C-PPE1 film.
基金This research was supported, in part, by grants from the National Science Foundation (NSF-DMR Intemational Program 96-16255 (F. R. and P. H. G.) and NSF-DMR Polymer Program 93-12823 and 96-16255 (J. Y., G. S., J. L. and P. H. G.)) and Grant Agency of the
文摘The morphology and crytal structure of poly(p-phenylene terephthalate) (PPT), prepared by confined thin filmmelt (CTFMP) and solution (CTFSP) and bulk solution polymerization, were characterized by transmission electronmicroscopy, electron dimaction and molecular modeling. The unit cell is monoclinic (P2_1/a space group) with parameters a =7.89, b = 5.49, c = 12.65 A, α=γ= 90°, β=100.33°, density = 1.48 g/cm^3, the a, b and β values differing slightly from thosereported previously in the literature. A degree of variation in relative intensities of hk0 reflections in, apparently, untilted[001] ED patterns was observed from a given sample, suggesting some variation in molecular packing. ED evidence wasfound for a second phase, with [001] appearing the same as for phase Ⅱ of the related poly(p-oxybenzoate) (PpOBA)polymer. CTFMP crystals polymerized above 220℃ (up to 370℃) and CTFSP crystals polymerized at 300℃ consisted oflamellae 100-200 A thick.
文摘Polymeric β-cyclodextrin (β-CD) supported by crosslinked poly(acrylamide-co-vinylamine) was synthesized as anartificial analog of hydrolytic enzyme and its catalysis of the hydrolysis of p-nitrophenyl acetate (p-NPA) was theninvestigated. The result showed that the polymer-supported β-CD could accelerate the hydrolytic reaction of p-NPA morequickly than β-CD itself and crosslinked poly(acrylamide-co-vinylamine) alone. The acceleration rate of the polymer-supported β-CD was about 10 times as fast as that of free β-CD in 0.01 mol/L phosphate buffer (pH 7.4) containing 32%DMSO at 37±0.1℃ when the molar amount of β-CD units in the polymer was equal to that of free β-CD in the experiments.The enhanced acceleration of thc polymer-supported β-CD should be ascribed to the cooperative contribution of theinclusion effect of β-CD ring and the nucleophilic effect of amino groups on the polymeric support.
