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
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
F-actins are semi-flexible polyelectrolytes and can be assembled into large polymer-actin complex with polymorphism through electrostatic interaction with polycations. This study investigates the structural phase beha...F-actins are semi-flexible polyelectrolytes and can be assembled into large polymer-actin complex with polymorphism through electrostatic interaction with polycations. This study investigates the structural phase behavior and the growth of polymer-actin complexes in terms of its longitudinal and lateral sizes. Our results show that formation of polymer-actin complexes is cooperative, and morphology and growth of polymer-actin complexes depend on polycation species and concentrations of polycation and salt in a constant actin concentration. We found that the longitudinal growth and lateral growth of polymer-actin complexes are dominated by different factors. This induces the structural polymorphism of polymer-actin complexes. Major factors to influence the polymorphism of polymer-actin complexes in polyelectrolytc system have been discussed. Our results indicate that the semi-flexible polyelectrolyte nature of F-actins is important for controlling the morphology and growth ofactin architectures in cell.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
基金This research is financially supported by SORST, JST and the Ministry of Education, Science, Sports, and Culture, Japan (Grant-in-Aid of Creative Scientific Research).
文摘F-actins are semi-flexible polyelectrolytes and can be assembled into large polymer-actin complex with polymorphism through electrostatic interaction with polycations. This study investigates the structural phase behavior and the growth of polymer-actin complexes in terms of its longitudinal and lateral sizes. Our results show that formation of polymer-actin complexes is cooperative, and morphology and growth of polymer-actin complexes depend on polycation species and concentrations of polycation and salt in a constant actin concentration. We found that the longitudinal growth and lateral growth of polymer-actin complexes are dominated by different factors. This induces the structural polymorphism of polymer-actin complexes. Major factors to influence the polymorphism of polymer-actin complexes in polyelectrolytc system have been discussed. Our results indicate that the semi-flexible polyelectrolyte nature of F-actins is important for controlling the morphology and growth ofactin architectures in cell.
