The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Klaus Schindhelm - One of the best experts on this subject based on the ideXlab platform.
-
polydimethylsiloxane polyether mixed macrodiol based polyurethane elastomers Biostability
Biomaterials, 2000Co-Authors: Darren J. Martin, Pathiraja A. Gunatillake, Simon J. Mccarthy, Gordon Francis Meijs, Laura Poole A Warren, Klaus SchindhelmAbstract:A series of four thermoplastic polyurethane elastomers were synthesized with varying proportions of poly(hexamethylene oxide) (PHMO) and poly(dimethylsiloxane) (PDMS) macrodiols. The macrodiol ratios (by weight) employed were (% PDMS:% PHMO) 100:0, 80:20, 50:50 and 20:80. The weight fraction of macrodiol in each polymer was fixed at 60%. The mixed macrodiols were reacted with 4,4'-methylenediphenyl diisocyanate (MDI) and 1,4-butanediol (BDO) chain extender. The Biostability of these polymers was assessed by strained subcutaneous implantation in sheep for three months followed by microscopic examination. Pellethane 2363-80A and 2363-55D were employed as control materials. The mechanical properties of the polymers were tested and discussed along with the Biostability results. The results showed that soft, flexible PDMS-based polyurethanes with very promising Biostability can be successfully produced using the mixed macrodiol approach. The formulation with 80% PDMS macrodiol produced the best result in terms of a combination of flexibility, strength and Biostability.
-
Polydimethylsiloxane/polyether-mixed macrodiol-based polyurethane elastomers : Biostability
Biomaterials, 2000Co-Authors: Darren J. Martin, Laura A. Poole Warren, Pathiraja A. Gunatillake, Simon J. Mccarthy, Gordon Francis Meijs, Klaus SchindhelmAbstract:A series of four thermoplastic polyurethane elastomers were synthesized with varying proportions of poly(hexamethylene oxide) (PHMO) and poly(dimethylsiloxane) (PDMS) macrodiols. The macrodiol ratios (by weight) employed were (% PDMS:% PHMO) 100:0, 80:20, 50:50 and 20:80. The weight fraction of macrodiol in each polymer was fixed at 60%. The mixed macrodiols were reacted with 4,4'-methylenediphenyl diisocyanate (MDI) and 1,4-butanediol (BDO) chain extender. The Biostability of these polymers was assessed by strained subcutaneous implantation in sheep for three months followed by microscopic examination. Pellethane 2363-80A and 2363-55D were employed as control materials. The mechanical properties of the polymers were tested and discussed along with the Biostability results. The results showed that soft, flexible PDMS-based polyurethanes with very promising Biostability can be successfully produced using the mixed macrodiol approach. The formulation with 80% PDMS macrodiol produced the best result in terms of a combination of flexibility, strength and Biostability.
Darren J. Martin - One of the best experts on this subject based on the ideXlab platform.
-
Designing Biostable Polyurethane Elastomers for Biomedical Implants
Australian Journal of Chemistry, 2003Co-Authors: Pathiraja A. Gunatillake, Darren J. Martin, Simon J. Mccarthy, Gordon Francis Meijs, Raju AdhikariAbstract:The chemical structure, synthesis, morphology, and properties of polyurethane elastomers are briefly discussed. The current understanding of the effect of chemical structure and the associated morphology on the stability of polyurethanes in the biological environments is reviewed. The degradation of conventional polyurethanes appears as surface or deep cracking, stiffening, and deterioration of mechanical properties, such as flex-fatigue resistance. Polyester and poly( tetramethylene oxide) based polyurethanes degrade by hydrolytic and oxidative degradation of ester and ether functional groups, respectively. The recent approaches to develop polyurethanes with improved long-term Biostability are based on developing novel polyether, hydrocarbon, polycarbonate, and siloxane macrodiols to replace degradation-prone polyester and polyether macrodiols in polyurethane formulations. The new approaches are discussed with respect to synthesis, properties and Biostability based on reported in vivo studies. Among the newly developed materials, siloxane-based polyurethanes have exhibited excellent Biostability and are expected to find many applications in biomedical implants.
-
polydimethylsiloxane polyether mixed macrodiol based polyurethane elastomers Biostability
Biomaterials, 2000Co-Authors: Darren J. Martin, Pathiraja A. Gunatillake, Simon J. Mccarthy, Gordon Francis Meijs, Laura Poole A Warren, Klaus SchindhelmAbstract:A series of four thermoplastic polyurethane elastomers were synthesized with varying proportions of poly(hexamethylene oxide) (PHMO) and poly(dimethylsiloxane) (PDMS) macrodiols. The macrodiol ratios (by weight) employed were (% PDMS:% PHMO) 100:0, 80:20, 50:50 and 20:80. The weight fraction of macrodiol in each polymer was fixed at 60%. The mixed macrodiols were reacted with 4,4'-methylenediphenyl diisocyanate (MDI) and 1,4-butanediol (BDO) chain extender. The Biostability of these polymers was assessed by strained subcutaneous implantation in sheep for three months followed by microscopic examination. Pellethane 2363-80A and 2363-55D were employed as control materials. The mechanical properties of the polymers were tested and discussed along with the Biostability results. The results showed that soft, flexible PDMS-based polyurethanes with very promising Biostability can be successfully produced using the mixed macrodiol approach. The formulation with 80% PDMS macrodiol produced the best result in terms of a combination of flexibility, strength and Biostability.
-
Polydimethylsiloxane/polyether-mixed macrodiol-based polyurethane elastomers : Biostability
Biomaterials, 2000Co-Authors: Darren J. Martin, Laura A. Poole Warren, Pathiraja A. Gunatillake, Simon J. Mccarthy, Gordon Francis Meijs, Klaus SchindhelmAbstract:A series of four thermoplastic polyurethane elastomers were synthesized with varying proportions of poly(hexamethylene oxide) (PHMO) and poly(dimethylsiloxane) (PDMS) macrodiols. The macrodiol ratios (by weight) employed were (% PDMS:% PHMO) 100:0, 80:20, 50:50 and 20:80. The weight fraction of macrodiol in each polymer was fixed at 60%. The mixed macrodiols were reacted with 4,4'-methylenediphenyl diisocyanate (MDI) and 1,4-butanediol (BDO) chain extender. The Biostability of these polymers was assessed by strained subcutaneous implantation in sheep for three months followed by microscopic examination. Pellethane 2363-80A and 2363-55D were employed as control materials. The mechanical properties of the polymers were tested and discussed along with the Biostability results. The results showed that soft, flexible PDMS-based polyurethanes with very promising Biostability can be successfully produced using the mixed macrodiol approach. The formulation with 80% PDMS macrodiol produced the best result in terms of a combination of flexibility, strength and Biostability.
Chunmao Han - One of the best experts on this subject based on the ideXlab platform.
-
collagen chitosan porous scaffolds with improved Biostability for skin tissue engineering
Biomaterials, 2003Co-Authors: Changyou Gao, Xueqing Hu, Jiacong Shen, Zhengwei Mao, Jie Zhou, Chunmao HanAbstract:Porous scaffolds for skin tissue engineering were fabricated by freeze-drying the mixture of collagen and chitosan solutions. Glutaraldehyde (GA) was used to treat the scaffolds to improve their Biostability. Confocal laser scanning microscopy observation confirmed the even distribution of these two constituent materials in the scaffold. The GA concentrations have a slight effect on the cross-section morphology and the swelling ratios of the cross-linked scaffolds. The collagenase digestion test proved that the presence of chitosan can obviously improve the Biostability of the collagen/chitosan scaffold under the GA treatment, where chitosan might function as a cross-linking bridge. A detail investigation found that a steady increase of the Biostability of the collagen/chitosan scaffold was achieved when GA concentration was lower than 0.1%, then was less influenced at a still higher GA concentration up to 0.25%. In vitro culture of human dermal fibroblasts proved that the GA-treated scaffold could retain the original good cytocompatibility of collagen to effectively accelerate cell infiltration and proliferation. In vivo animal tests further revealed that the scaffold could sufficiently support and accelerate the fibroblasts infiltration from the surrounding tissue. Immunohistochemistry analysis of the scaffold embedded for 28 days indicated that the biodegradation of the 0.25% GA-treated scaffold is a long-term process. All these results suggest that collagen/chitosan scaffold cross-linked by GA is a potential candidate for dermal equivalent with enhanced Biostability and good biocompatibility.
-
Collagen/chitosan porous scaffolds with improved Biostability for skin tissue engineering.
Biomaterials, 2003Co-Authors: Changyou Gao, Zhengwei Mao, Jiacong Shen, Jie Zhou, Chunmao HanAbstract:Porous scaffolds for skin tissue engineering were fabricated by freeze-drying the mixture of collagen and chitosan solutions. Glutaraldehyde (GA) was used to treat the scaffolds to improve their Biostability. Confocal laser scanning microscopy observation confirmed the even distribution of these two constituent materials in the scaffold. The GA concentrations have a slight effect on the cross-section morphology and the swelling ratios of the cross-linked scaffolds. The collagenase digestion test proved that the presence of chitosan can obviously improve the Biostability of the collagen/chitosan scaffold under the GA treatment, where chitosan might function as a cross-linking bridge. A detail investigation found that a steady increase of the Biostability of the collagen/chitosan scaffold was achieved when GA concentration was lower than 0.1%, then was less influenced at a still higher GA concentration up to 0.25%. In vitro culture of human dermal fibroblasts proved that the GA-treated scaffold could retain the original good cytocompatibility of collagen to effectively accelerate cell infiltration and proliferation. In vivo animal tests further revealed that the scaffold could sufficiently support and accelerate the fibroblasts infiltration from the surrounding tissue. Immunohistochemistry analysis of the scaffold embedded for 28 days indicated that the biodegradation of the 0.25% GA-treated scaffold is a long-term process. All these results suggest that collagen/chitosan scaffold cross-linked by GA is a potential candidate for dermal equivalent with enhanced Biostability and good biocompatibility.
Pathiraja A. Gunatillake - One of the best experts on this subject based on the ideXlab platform.
-
Designing Biostable Polyurethane Elastomers for Biomedical Implants
Australian Journal of Chemistry, 2003Co-Authors: Pathiraja A. Gunatillake, Darren J. Martin, Simon J. Mccarthy, Gordon Francis Meijs, Raju AdhikariAbstract:The chemical structure, synthesis, morphology, and properties of polyurethane elastomers are briefly discussed. The current understanding of the effect of chemical structure and the associated morphology on the stability of polyurethanes in the biological environments is reviewed. The degradation of conventional polyurethanes appears as surface or deep cracking, stiffening, and deterioration of mechanical properties, such as flex-fatigue resistance. Polyester and poly( tetramethylene oxide) based polyurethanes degrade by hydrolytic and oxidative degradation of ester and ether functional groups, respectively. The recent approaches to develop polyurethanes with improved long-term Biostability are based on developing novel polyether, hydrocarbon, polycarbonate, and siloxane macrodiols to replace degradation-prone polyester and polyether macrodiols in polyurethane formulations. The new approaches are discussed with respect to synthesis, properties and Biostability based on reported in vivo studies. Among the newly developed materials, siloxane-based polyurethanes have exhibited excellent Biostability and are expected to find many applications in biomedical implants.
-
polydimethylsiloxane polyether mixed macrodiol based polyurethane elastomers Biostability
Biomaterials, 2000Co-Authors: Darren J. Martin, Pathiraja A. Gunatillake, Simon J. Mccarthy, Gordon Francis Meijs, Laura Poole A Warren, Klaus SchindhelmAbstract:A series of four thermoplastic polyurethane elastomers were synthesized with varying proportions of poly(hexamethylene oxide) (PHMO) and poly(dimethylsiloxane) (PDMS) macrodiols. The macrodiol ratios (by weight) employed were (% PDMS:% PHMO) 100:0, 80:20, 50:50 and 20:80. The weight fraction of macrodiol in each polymer was fixed at 60%. The mixed macrodiols were reacted with 4,4'-methylenediphenyl diisocyanate (MDI) and 1,4-butanediol (BDO) chain extender. The Biostability of these polymers was assessed by strained subcutaneous implantation in sheep for three months followed by microscopic examination. Pellethane 2363-80A and 2363-55D were employed as control materials. The mechanical properties of the polymers were tested and discussed along with the Biostability results. The results showed that soft, flexible PDMS-based polyurethanes with very promising Biostability can be successfully produced using the mixed macrodiol approach. The formulation with 80% PDMS macrodiol produced the best result in terms of a combination of flexibility, strength and Biostability.
-
Polydimethylsiloxane/polyether-mixed macrodiol-based polyurethane elastomers : Biostability
Biomaterials, 2000Co-Authors: Darren J. Martin, Laura A. Poole Warren, Pathiraja A. Gunatillake, Simon J. Mccarthy, Gordon Francis Meijs, Klaus SchindhelmAbstract:A series of four thermoplastic polyurethane elastomers were synthesized with varying proportions of poly(hexamethylene oxide) (PHMO) and poly(dimethylsiloxane) (PDMS) macrodiols. The macrodiol ratios (by weight) employed were (% PDMS:% PHMO) 100:0, 80:20, 50:50 and 20:80. The weight fraction of macrodiol in each polymer was fixed at 60%. The mixed macrodiols were reacted with 4,4'-methylenediphenyl diisocyanate (MDI) and 1,4-butanediol (BDO) chain extender. The Biostability of these polymers was assessed by strained subcutaneous implantation in sheep for three months followed by microscopic examination. Pellethane 2363-80A and 2363-55D were employed as control materials. The mechanical properties of the polymers were tested and discussed along with the Biostability results. The results showed that soft, flexible PDMS-based polyurethanes with very promising Biostability can be successfully produced using the mixed macrodiol approach. The formulation with 80% PDMS macrodiol produced the best result in terms of a combination of flexibility, strength and Biostability.
Simon J. Mccarthy - One of the best experts on this subject based on the ideXlab platform.
-
Designing Biostable Polyurethane Elastomers for Biomedical Implants
Australian Journal of Chemistry, 2003Co-Authors: Pathiraja A. Gunatillake, Darren J. Martin, Simon J. Mccarthy, Gordon Francis Meijs, Raju AdhikariAbstract:The chemical structure, synthesis, morphology, and properties of polyurethane elastomers are briefly discussed. The current understanding of the effect of chemical structure and the associated morphology on the stability of polyurethanes in the biological environments is reviewed. The degradation of conventional polyurethanes appears as surface or deep cracking, stiffening, and deterioration of mechanical properties, such as flex-fatigue resistance. Polyester and poly( tetramethylene oxide) based polyurethanes degrade by hydrolytic and oxidative degradation of ester and ether functional groups, respectively. The recent approaches to develop polyurethanes with improved long-term Biostability are based on developing novel polyether, hydrocarbon, polycarbonate, and siloxane macrodiols to replace degradation-prone polyester and polyether macrodiols in polyurethane formulations. The new approaches are discussed with respect to synthesis, properties and Biostability based on reported in vivo studies. Among the newly developed materials, siloxane-based polyurethanes have exhibited excellent Biostability and are expected to find many applications in biomedical implants.
-
polydimethylsiloxane polyether mixed macrodiol based polyurethane elastomers Biostability
Biomaterials, 2000Co-Authors: Darren J. Martin, Pathiraja A. Gunatillake, Simon J. Mccarthy, Gordon Francis Meijs, Laura Poole A Warren, Klaus SchindhelmAbstract:A series of four thermoplastic polyurethane elastomers were synthesized with varying proportions of poly(hexamethylene oxide) (PHMO) and poly(dimethylsiloxane) (PDMS) macrodiols. The macrodiol ratios (by weight) employed were (% PDMS:% PHMO) 100:0, 80:20, 50:50 and 20:80. The weight fraction of macrodiol in each polymer was fixed at 60%. The mixed macrodiols were reacted with 4,4'-methylenediphenyl diisocyanate (MDI) and 1,4-butanediol (BDO) chain extender. The Biostability of these polymers was assessed by strained subcutaneous implantation in sheep for three months followed by microscopic examination. Pellethane 2363-80A and 2363-55D were employed as control materials. The mechanical properties of the polymers were tested and discussed along with the Biostability results. The results showed that soft, flexible PDMS-based polyurethanes with very promising Biostability can be successfully produced using the mixed macrodiol approach. The formulation with 80% PDMS macrodiol produced the best result in terms of a combination of flexibility, strength and Biostability.
-
Polydimethylsiloxane/polyether-mixed macrodiol-based polyurethane elastomers : Biostability
Biomaterials, 2000Co-Authors: Darren J. Martin, Laura A. Poole Warren, Pathiraja A. Gunatillake, Simon J. Mccarthy, Gordon Francis Meijs, Klaus SchindhelmAbstract:A series of four thermoplastic polyurethane elastomers were synthesized with varying proportions of poly(hexamethylene oxide) (PHMO) and poly(dimethylsiloxane) (PDMS) macrodiols. The macrodiol ratios (by weight) employed were (% PDMS:% PHMO) 100:0, 80:20, 50:50 and 20:80. The weight fraction of macrodiol in each polymer was fixed at 60%. The mixed macrodiols were reacted with 4,4'-methylenediphenyl diisocyanate (MDI) and 1,4-butanediol (BDO) chain extender. The Biostability of these polymers was assessed by strained subcutaneous implantation in sheep for three months followed by microscopic examination. Pellethane 2363-80A and 2363-55D were employed as control materials. The mechanical properties of the polymers were tested and discussed along with the Biostability results. The results showed that soft, flexible PDMS-based polyurethanes with very promising Biostability can be successfully produced using the mixed macrodiol approach. The formulation with 80% PDMS macrodiol produced the best result in terms of a combination of flexibility, strength and Biostability.