In order to create a functionalized biodegradable polymer for vascular tissue engineering application,poly(DL- lactide-co-RS-β-malic acid)(PDLLMAc)was synthesized.PDLLMAc was obtained after hydrogenolysis of poly(DL-...In order to create a functionalized biodegradable polymer for vascular tissue engineering application,poly(DL- lactide-co-RS-β-malic acid)(PDLLMAc)was synthesized.PDLLMAc was obtained after hydrogenolysis of poly(DL- lactide-co-RS-β-benzyl malolactonate)(PDLLMA),which was from the ring-opening polymerization of DL-lactide(DLLA) and RS-β-benzyl malolactonate(MA)using stannous octoate as catalyst.The copolymers were characterized by ~1H-NMR, FTIR,GPC and DSC.The tensile strength and water uptake of the copoly...展开更多
Poly(lactide acid)(PLA)foams have shown considerable promise as eco-friendly alternatives to nondegradable plastic foams,such as polystyrene(PS)foams.Nevertheless,PLA foam typically suffers from low heat-resistance an...Poly(lactide acid)(PLA)foams have shown considerable promise as eco-friendly alternatives to nondegradable plastic foams,such as polystyrene(PS)foams.Nevertheless,PLA foam typically suffers from low heat-resistance and poor cellular structure stemming from its inherent slow crystallization rate and low melt strength.In this study,a high-performance PLA foam with well-defined cell morphology,exceptional strength and enhanced heat-resistance was successfully fabricated via a core-back microcellular injection molding(MIM)process.Differential scanning calorimetry(DSC)results revealed that the added hydrazine-based nucleating agent(HNA)significantly increased the crystallization temperature and accelerated the crystallization process of PLA.Remarkably,the addition of a 1.5 wt%of HNA led to a significant reduction in PLA’s cell size,from 43.5µm to 2.87µm,and a remarkable increase in cell density,from 1.08×10^(7)cells/cm^(3)to 2.15×10^(10)cells/cm^(3).This enhancement resulted in a final crystallinity of approximately 55.7%for the PLA blend foam,a marked improvement compared to the pure PLA foam.Furthermore,at 1.5 wt%HNA concentration,the tensile strength and tensile toughness of PLA blend foams demonstrated remarkable improvements of 136%and 463%,respectively.Additionally,the Vicat softening temperature of PLA blend foam increased significantly to 134.8°C,whereas the pure PLA foam exhibited only about 59.7℃.These findings underscore the potential for the preparation of lightweight injection-molded PLA foam with enhanced toughness and heat-resistance,which offers a viable approach for the production of high-performance PLA foams suitable for large-scale applications.展开更多
Poly(lactide-co-glycolide acid)(PLGA) is an extraordinary well-described polymer and has excellent pharmaceutical properties like high biocompatibility and good biodegradability. Hence, it is one of the most used mate...Poly(lactide-co-glycolide acid)(PLGA) is an extraordinary well-described polymer and has excellent pharmaceutical properties like high biocompatibility and good biodegradability. Hence, it is one of the most used materials for drug delivery and biomedical systems, also being present in several US Food and Drug Administration-approved carrier systems and therapeutic devices. For both applications, the quantification of the polymer is inalienable. During the development of a production process, parameters like yield or loading efficacy are essential to be determined. Although PLGA is a well-defined biomaterial,it still lacks a sensitive and convenient quantification approach for PLGA-based systems. Thus, we present a novel method for the fast and precise quantification of PLGA by RP-HPLC. The polymer is hydrolyzed into its monomers, glycolic acid and lactic acid. Afterwards, the monomers are derivatized with the absorption-enhancing molecule 2,4′-dibromoacetophenone. Furthermore, the wavelength of the derivatized monomers is shifted to higher wavelengths, where the used solvents show a lower absorption,increasing the sensitivity and detectability. The developed method has a detection limit of 0.1 mg/mL,enabling the quantification of low amounts of PLGA. By quantifying both monomers separately, information about the PLGA monomer ratio can be also directly obtained, being relevant for degradation behavior. Compared to existing approaches, like gravimetric or nuclear magnetic resonance measurements, which are tedious or expensive, the developed method is fast, ideal for routine screening, and it is selective since no stabilizer or excipient is interfering. Due to the high sensitivity and rapidity of the method, it is suitable for both laboratory and industrial uses.展开更多
Lactide was synthesized using lactic acid and stannous octoate as raw material and catalyst, respectively. Poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) was prepared by lactide and poly (ethylene glycol) (PEG) via...Lactide was synthesized using lactic acid and stannous octoate as raw material and catalyst, respectively. Poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) was prepared by lactide and poly (ethylene glycol) (PEG) via ring-opening polymerization. The most appropriate technological conditions of synthesis of lactide were researched in the paper. The copolymers were measured by Infrared spectroscopy (IR) and <sup>1</sup>H nuclear magnetic resonance (<sup>1</sup>H NMR). The results proved that the lactide and PLA-PEG were synthesized successfully. Hydrophilic performance of the copolymer was measured by a water contact angle tester after prepared into a flat membrane. The water contact angle changed from 81.5? to 71.6?, which proved that the hydrophily of PLA-PEG was better than PLA.展开更多
Inhibition of neurite growth, which is in large part mediated by the Nogo-66 receptor, affects neural regeneration following bone marrow mesenchymal stem cell transplantation. The tissue engineering scaffold poly（D,L...Inhibition of neurite growth, which is in large part mediated by the Nogo-66 receptor, affects neural regeneration following bone marrow mesenchymal stem cell transplantation. The tissue engineering scaffold poly（D,L-lactide-co-glycolic acid） has good histocompatibility and can promote the growth of regenerating nerve fibers. The present study used small interfering RNA to silence Nogo-66 receptor gene expression in bone marrow mesenchymal stem cells and Schwann cells, which were subsequently transplanted with poly（D,L-lactide-co-glycolic acid） into the spinal cord lesion regions in rats. Simultaneously, rats treated with scaffold only were taken as the control group. Hematoxylin-eosin staining and immunohistochemistry revealed that at 4 weeks after transplantation, rats had good motor function of the hind limb after treatment with Nogo-66 receptor gene-silenced ceils prus the poly（O,L-lactide-co-glycolic acid） scaffold compared with rats treated with scaffold only, and the number of bone marrow mesenchymal stem cells and neuron-like cells was also increased. At 8 weeks after transplantation, horseradish peroxidase tracing and transmission electron microscopy showed a large number of unmyelinated and myelinated nerve fibers, as well as intact regenerating axonal myelin sheath following spinal cord hemisection injury. These experimental findings indicate that transplantation of Nogo-66 receptor gene-silenced bone marrow mesenchymal stem cells and Schwann cells plus a poly（D,L-lactide-co-glycolic acid） scaffold can significantly enhance axonal regeneration of spinal cord neurons and improve motor function of the extremities in rats following spinal cord injury.展开更多
Biodegradable poly(alc-alt-Asp) was synthesized by ring-opening polymerization of the monomer 3-(S)-[(benzyloxycarbonyl)methyl] -morpholine-2, 5-dione and subsequent catalytic hydrogenation. Copolymers of the monomer ...Biodegradable poly(alc-alt-Asp) was synthesized by ring-opening polymerization of the monomer 3-(S)-[(benzyloxycarbonyl)methyl] -morpholine-2, 5-dione and subsequent catalytic hydrogenation. Copolymers of the monomer with glycolide, D,L-lactide and L-lactide were also prepared.展开更多
文摘In order to create a functionalized biodegradable polymer for vascular tissue engineering application,poly(DL- lactide-co-RS-β-malic acid)(PDLLMAc)was synthesized.PDLLMAc was obtained after hydrogenolysis of poly(DL- lactide-co-RS-β-benzyl malolactonate)(PDLLMA),which was from the ring-opening polymerization of DL-lactide(DLLA) and RS-β-benzyl malolactonate(MA)using stannous octoate as catalyst.The copolymers were characterized by ~1H-NMR, FTIR,GPC and DSC.The tensile strength and water uptake of the copoly...
基金supported by the National Natural Science Foundation of China(No.52003280)the Zhejiang Provincial Natural Science Foundation of China(No.LQ21B040003)+1 种基金the S&T Innovation 2025 Major Special Programme of Ningbo(No.2021Z052)the Chinese Academy of Sciences Pioneer Hundred Talents Program.
文摘Poly(lactide acid)(PLA)foams have shown considerable promise as eco-friendly alternatives to nondegradable plastic foams,such as polystyrene(PS)foams.Nevertheless,PLA foam typically suffers from low heat-resistance and poor cellular structure stemming from its inherent slow crystallization rate and low melt strength.In this study,a high-performance PLA foam with well-defined cell morphology,exceptional strength and enhanced heat-resistance was successfully fabricated via a core-back microcellular injection molding(MIM)process.Differential scanning calorimetry(DSC)results revealed that the added hydrazine-based nucleating agent(HNA)significantly increased the crystallization temperature and accelerated the crystallization process of PLA.Remarkably,the addition of a 1.5 wt%of HNA led to a significant reduction in PLA’s cell size,from 43.5µm to 2.87µm,and a remarkable increase in cell density,from 1.08×10^(7)cells/cm^(3)to 2.15×10^(10)cells/cm^(3).This enhancement resulted in a final crystallinity of approximately 55.7%for the PLA blend foam,a marked improvement compared to the pure PLA foam.Furthermore,at 1.5 wt%HNA concentration,the tensile strength and tensile toughness of PLA blend foams demonstrated remarkable improvements of 136%and 463%,respectively.Additionally,the Vicat softening temperature of PLA blend foam increased significantly to 134.8°C,whereas the pure PLA foam exhibited only about 59.7℃.These findings underscore the potential for the preparation of lightweight injection-molded PLA foam with enhanced toughness and heat-resistance,which offers a viable approach for the production of high-performance PLA foams suitable for large-scale applications.
文摘Poly(lactide-co-glycolide acid)(PLGA) is an extraordinary well-described polymer and has excellent pharmaceutical properties like high biocompatibility and good biodegradability. Hence, it is one of the most used materials for drug delivery and biomedical systems, also being present in several US Food and Drug Administration-approved carrier systems and therapeutic devices. For both applications, the quantification of the polymer is inalienable. During the development of a production process, parameters like yield or loading efficacy are essential to be determined. Although PLGA is a well-defined biomaterial,it still lacks a sensitive and convenient quantification approach for PLGA-based systems. Thus, we present a novel method for the fast and precise quantification of PLGA by RP-HPLC. The polymer is hydrolyzed into its monomers, glycolic acid and lactic acid. Afterwards, the monomers are derivatized with the absorption-enhancing molecule 2,4′-dibromoacetophenone. Furthermore, the wavelength of the derivatized monomers is shifted to higher wavelengths, where the used solvents show a lower absorption,increasing the sensitivity and detectability. The developed method has a detection limit of 0.1 mg/mL,enabling the quantification of low amounts of PLGA. By quantifying both monomers separately, information about the PLGA monomer ratio can be also directly obtained, being relevant for degradation behavior. Compared to existing approaches, like gravimetric or nuclear magnetic resonance measurements, which are tedious or expensive, the developed method is fast, ideal for routine screening, and it is selective since no stabilizer or excipient is interfering. Due to the high sensitivity and rapidity of the method, it is suitable for both laboratory and industrial uses.
文摘Lactide was synthesized using lactic acid and stannous octoate as raw material and catalyst, respectively. Poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) was prepared by lactide and poly (ethylene glycol) (PEG) via ring-opening polymerization. The most appropriate technological conditions of synthesis of lactide were researched in the paper. The copolymers were measured by Infrared spectroscopy (IR) and <sup>1</sup>H nuclear magnetic resonance (<sup>1</sup>H NMR). The results proved that the lactide and PLA-PEG were synthesized successfully. Hydrophilic performance of the copolymer was measured by a water contact angle tester after prepared into a flat membrane. The water contact angle changed from 81.5? to 71.6?, which proved that the hydrophily of PLA-PEG was better than PLA.
基金sponsored by the Science and Technology Foundation of Tianjin Health Bureau,No. 2010ky04the Application Basis and Front Technology Projects of Tianjin (Science and Technology Foundation of Tianjin),No.12JCYBJC18000
文摘Inhibition of neurite growth, which is in large part mediated by the Nogo-66 receptor, affects neural regeneration following bone marrow mesenchymal stem cell transplantation. The tissue engineering scaffold poly（D,L-lactide-co-glycolic acid） has good histocompatibility and can promote the growth of regenerating nerve fibers. The present study used small interfering RNA to silence Nogo-66 receptor gene expression in bone marrow mesenchymal stem cells and Schwann cells, which were subsequently transplanted with poly（D,L-lactide-co-glycolic acid） into the spinal cord lesion regions in rats. Simultaneously, rats treated with scaffold only were taken as the control group. Hematoxylin-eosin staining and immunohistochemistry revealed that at 4 weeks after transplantation, rats had good motor function of the hind limb after treatment with Nogo-66 receptor gene-silenced ceils prus the poly（O,L-lactide-co-glycolic acid） scaffold compared with rats treated with scaffold only, and the number of bone marrow mesenchymal stem cells and neuron-like cells was also increased. At 8 weeks after transplantation, horseradish peroxidase tracing and transmission electron microscopy showed a large number of unmyelinated and myelinated nerve fibers, as well as intact regenerating axonal myelin sheath following spinal cord hemisection injury. These experimental findings indicate that transplantation of Nogo-66 receptor gene-silenced bone marrow mesenchymal stem cells and Schwann cells plus a poly（D,L-lactide-co-glycolic acid） scaffold can significantly enhance axonal regeneration of spinal cord neurons and improve motor function of the extremities in rats following spinal cord injury.
文摘Biodegradable poly(alc-alt-Asp) was synthesized by ring-opening polymerization of the monomer 3-(S)-[(benzyloxycarbonyl)methyl] -morpholine-2, 5-dione and subsequent catalytic hydrogenation. Copolymers of the monomer with glycolide, D,L-lactide and L-lactide were also prepared.
