Developing advanced technologies to address the bacterial associated infections is an urgent requirement for metallic implants and devices.Here,we report a novel phosphonate/quaternary amine block polymer as the high-...Developing advanced technologies to address the bacterial associated infections is an urgent requirement for metallic implants and devices.Here,we report a novel phosphonate/quaternary amine block polymer as the high-efficiency antibacterial coating for metallic substrates.Three pDEMMP-b-pTMAEMA block polymers that bearing identical phosphonate segments(repeat units of 15)but varied cationic segments(repeat units of 8,45,and 70)were precisely prepared.Stable cationic polymer coatings were constructed on TC4 substrates based on the strong covalent binding between phosphonate group and metallic substrate.Robust relationship between the segment chain length of the polymer coating and the antibacterial property endowed to the substrates have been established based on quantitative and qualitative evaluations.Results showed that the antibacterial rate of the modified TC4 surface were 95.8%of S.aureus and 92.9%of E.coli cells attached.Interestingly,unlike the cationic free polymer or cationic hydrogels,the surface anchored cationic polymers do compromise the viability of the attached C2C12 cells but without significant cytotoxicity.In addition,the phosphonate/quate rnary amine block polymers can be easily constructed on titanium,stainless steel,and Ni/Cr alloy with significantly improved antibacterial property,indicating the generality of the block polymer for surface antibacterial modification of bio-metals.展开更多
A selenium-functionalizedε-caprolactone was synthesized by introducing a phenyl selenide group at the 7-position.A polymer was obtained through the ring-opening polymerization of this monomer in a base/thiourea binar...A selenium-functionalizedε-caprolactone was synthesized by introducing a phenyl selenide group at the 7-position.A polymer was obtained through the ring-opening polymerization of this monomer in a base/thiourea binary organocatalytic system.A living polymerization process was achieved under mild conditions.The resulting polymers had a controlled molecular weight with a narrow molecular weight distributions and high end-group fidelity.Random copolymers could be obtained by copolymerizing this monomer withε-caprolactone.The thermal degradation temperature of the obtained copolymers decreased with the increasing molar ratio of selenide functionalized monomer in copolymers,while the glass transition temperature increased.In addition,the phenyl selenide side group could be further modified to a polyselenonium salt,which resulted in a polymer with good antibacterial properties.The survival rate of E.coli and S.aureus was only 9%with a polymer concentration of 62.5μg/mL.展开更多
Background: Abdominal adhesions develop on damaged peritoneal surfaces and constitute a significant health related problem. Previous animal studies have shown promising anti-adhesive effects when administering the pol...Background: Abdominal adhesions develop on damaged peritoneal surfaces and constitute a significant health related problem. Previous animal studies have shown promising anti-adhesive effects when administering the polycation α-poly-L-lysine (αPL) and the polyanion poly-L-glutamate (PG) together. The objective of the study was to examine the effect of these differently charged polypeptides when administered by spraying and to evaluate any possible effect on fibrinolysis, fibrosis and inflammation. Methods: Rabbits were treated with PLPG after cecal abrasive surgery and analysis from peritoneal biopsies of active tPa/PAI-1 complex and from peritoneal fluid of IL-6 and active TGFb1 at day 0, 1, 4 and 10 were measured after surgery. Histological specimens were analyzed on day 10 regarding inflammation and fibrosis. Peritoneal adhesions were evaluated by adhesion score. All values were compared to the control group (NaCl). Results: PLPG-treated rabbits had a significant diminished adhesion score on day 10 as compared to the control group (p < 0.005). Significantly reduced collagen depositions on the peritoneum were seen in the PLPG group when evaluating the histological specimens (p < 0.05). No significant differences between the experimental and control groups were seen in peritoneal fluid when analyzing for active protein levels. Conclusion: This is the first study to investigate the effect on key parameters in adhesion formation as well as the preventive effect of the PLPG complex on abdominal adhesions in rabbits and also the first study where administration by spraying the polypeptides was used. PLPG was non-toxic in this setting and without significant differences in adhesion formation parameters and a significant reduction in adhesions was observed. This was verified both macroscopically and histologically.展开更多
BACKGROUND：It has been reported that chitosan nerve conduits could support axon elongation and improve relevant function during in vivo nerve regeneration. OBJECTIVE： To investigate in vitro biocompatibility of thre...BACKGROUND：It has been reported that chitosan nerve conduits could support axon elongation and improve relevant function during in vivo nerve regeneration. OBJECTIVE： To investigate in vitro biocompatibility of three novel, chitosan/polycation composite materials for nerve regeneration in cultured mouse Schwann cells and PC12 cells. DESIGN, TIME AND SETTING： The observational, control experiments for nerve tissue engineering were performed at the Department of Biological Sciences and Biotechnology of Tsinghua University from August 2007 to January 2008. MATERIALS： Mouse Schwann cells were isolated from the sciatic nerve of 5–7-day-old BALB/C mice. PC12 cells were purchased from the American Type Culture Collection （ATCC, USA）. Chitosan was purchased from Tsingdao Haisheng Co., China. Poly-L-lysine hydrochloride （PLL）, polyethyleneimine （PEI） poly-L-ornithine hydrobromide （POR）, and S-100 antibody was purchased from Sigma Chemical Co., USA. Cell Counting Kit-8 （CCK-8） was purchased from Dojindo Chemical Co., Japan. METHODS： Three chitosan/polycation composite materials for nerve regeneration （PLL-0.25, PEI-0.25, and POR-0.25） were produced by blending chitosan with 0.25% （w/w） poly-L-lysine, polyethyleneimine, and poly-L-ornithine. Pure chitosan was utilized as the control. After 3 days of culture, the morphology of mouse Schwann and PC12 cells cultured on all substrates was observed with an inverted phase contrast microscope. Mouse Schwann cells were stained by immunofluorescence labeling S-100 protein and nuclei, followed by identification with a confocal laser-scanning microscope. The amount of proliferating mouse Schwann and PC12 cells was determined by CCK-8 after 1, 3, and 5 days in culture. The level of PC12 cell differentiation on all substrates was assessed by measuring neurite length at 1, 3, and 5 days after seeding. MAIN OUTCOME MEASURES： Morphology and amount of proliferation of mouse Schwann cells and PC12 cells cultured on chitosan and three polycation-modif展开更多
基金the grant supports from the National Natural Science Foundation of China(No.21504046)the Six Talent Peaks Project in Jiangsu Province(SWYY-060)+1 种基金the Projects of Nanjing Normal University(No.184080H20192184080H10386)。
文摘Developing advanced technologies to address the bacterial associated infections is an urgent requirement for metallic implants and devices.Here,we report a novel phosphonate/quaternary amine block polymer as the high-efficiency antibacterial coating for metallic substrates.Three pDEMMP-b-pTMAEMA block polymers that bearing identical phosphonate segments(repeat units of 15)but varied cationic segments(repeat units of 8,45,and 70)were precisely prepared.Stable cationic polymer coatings were constructed on TC4 substrates based on the strong covalent binding between phosphonate group and metallic substrate.Robust relationship between the segment chain length of the polymer coating and the antibacterial property endowed to the substrates have been established based on quantitative and qualitative evaluations.Results showed that the antibacterial rate of the modified TC4 surface were 95.8%of S.aureus and 92.9%of E.coli cells attached.Interestingly,unlike the cationic free polymer or cationic hydrogels,the surface anchored cationic polymers do compromise the viability of the attached C2C12 cells but without significant cytotoxicity.In addition,the phosphonate/quate rnary amine block polymers can be easily constructed on titanium,stainless steel,and Ni/Cr alloy with significantly improved antibacterial property,indicating the generality of the block polymer for surface antibacterial modification of bio-metals.
基金financially supported by the National Natural Science Foundation of China(No.21871200)the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions。
文摘A selenium-functionalizedε-caprolactone was synthesized by introducing a phenyl selenide group at the 7-position.A polymer was obtained through the ring-opening polymerization of this monomer in a base/thiourea binary organocatalytic system.A living polymerization process was achieved under mild conditions.The resulting polymers had a controlled molecular weight with a narrow molecular weight distributions and high end-group fidelity.Random copolymers could be obtained by copolymerizing this monomer withε-caprolactone.The thermal degradation temperature of the obtained copolymers decreased with the increasing molar ratio of selenide functionalized monomer in copolymers,while the glass transition temperature increased.In addition,the phenyl selenide side group could be further modified to a polyselenonium salt,which resulted in a polymer with good antibacterial properties.The survival rate of E.coli and S.aureus was only 9%with a polymer concentration of 62.5μg/mL.
基金performed in parts due to grants from Ake Wiberg Foundation,Magnus Bergvall Foundation,Zoegas foundation and Regional hospital funds.
文摘Background: Abdominal adhesions develop on damaged peritoneal surfaces and constitute a significant health related problem. Previous animal studies have shown promising anti-adhesive effects when administering the polycation α-poly-L-lysine (αPL) and the polyanion poly-L-glutamate (PG) together. The objective of the study was to examine the effect of these differently charged polypeptides when administered by spraying and to evaluate any possible effect on fibrinolysis, fibrosis and inflammation. Methods: Rabbits were treated with PLPG after cecal abrasive surgery and analysis from peritoneal biopsies of active tPa/PAI-1 complex and from peritoneal fluid of IL-6 and active TGFb1 at day 0, 1, 4 and 10 were measured after surgery. Histological specimens were analyzed on day 10 regarding inflammation and fibrosis. Peritoneal adhesions were evaluated by adhesion score. All values were compared to the control group (NaCl). Results: PLPG-treated rabbits had a significant diminished adhesion score on day 10 as compared to the control group (p < 0.005). Significantly reduced collagen depositions on the peritoneum were seen in the PLPG group when evaluating the histological specimens (p < 0.05). No significant differences between the experimental and control groups were seen in peritoneal fluid when analyzing for active protein levels. Conclusion: This is the first study to investigate the effect on key parameters in adhesion formation as well as the preventive effect of the PLPG complex on abdominal adhesions in rabbits and also the first study where administration by spraying the polypeptides was used. PLPG was non-toxic in this setting and without significant differences in adhesion formation parameters and a significant reduction in adhesions was observed. This was verified both macroscopically and histologically.
基金National Basic Research Program of China, ("973" Program), No. 2005CB623905Tsinghua-Yue-Yuen Medical Science Fund, Beijing Municipal Science & Technology Commission, No. H060920050430the National Natural Science Foundation of China, No. 30670528, 30700848, 30772443
文摘BACKGROUND：It has been reported that chitosan nerve conduits could support axon elongation and improve relevant function during in vivo nerve regeneration. OBJECTIVE： To investigate in vitro biocompatibility of three novel, chitosan/polycation composite materials for nerve regeneration in cultured mouse Schwann cells and PC12 cells. DESIGN, TIME AND SETTING： The observational, control experiments for nerve tissue engineering were performed at the Department of Biological Sciences and Biotechnology of Tsinghua University from August 2007 to January 2008. MATERIALS： Mouse Schwann cells were isolated from the sciatic nerve of 5–7-day-old BALB/C mice. PC12 cells were purchased from the American Type Culture Collection （ATCC, USA）. Chitosan was purchased from Tsingdao Haisheng Co., China. Poly-L-lysine hydrochloride （PLL）, polyethyleneimine （PEI） poly-L-ornithine hydrobromide （POR）, and S-100 antibody was purchased from Sigma Chemical Co., USA. Cell Counting Kit-8 （CCK-8） was purchased from Dojindo Chemical Co., Japan. METHODS： Three chitosan/polycation composite materials for nerve regeneration （PLL-0.25, PEI-0.25, and POR-0.25） were produced by blending chitosan with 0.25% （w/w） poly-L-lysine, polyethyleneimine, and poly-L-ornithine. Pure chitosan was utilized as the control. After 3 days of culture, the morphology of mouse Schwann and PC12 cells cultured on all substrates was observed with an inverted phase contrast microscope. Mouse Schwann cells were stained by immunofluorescence labeling S-100 protein and nuclei, followed by identification with a confocal laser-scanning microscope. The amount of proliferating mouse Schwann and PC12 cells was determined by CCK-8 after 1, 3, and 5 days in culture. The level of PC12 cell differentiation on all substrates was assessed by measuring neurite length at 1, 3, and 5 days after seeding. MAIN OUTCOME MEASURES： Morphology and amount of proliferation of mouse Schwann cells and PC12 cells cultured on chitosan and three polycation-modif
