The Experts below are selected from a list of 9624 Experts worldwide ranked by ideXlab platform
Jeffrey O Hollinger - One of the best experts on this subject based on the ideXlab platform.
-
synthesis of biocompatible segmented Polyurethanes from aliphatic diisocyanates and diurea diol chain extenders
Acta Biomaterialia, 2005Co-Authors: Scott A Guelcher, Katie M Gallagher, Jonathan E Didier, Derek B Klinedinst, John S Doctor, Aaron S Goldstein, Garth L Wilkes, Eric J Beckman, Jeffrey O HollingerAbstract:Abstract Many polyurethane elastomers display excellent mechanical properties and adequate biocompatibility. However, many medical-grade Polyurethanes are prepared from aromatic diisocyanates and can degrade in vivo to carcinogenic aromatic diamines, although the question of whether the concentrations of these harmful degradation products attain physiologically relevant levels is currently unresolved and strongly debated. It is therefore desirable to synthesize new medical-grade Polyurethanes from less toxic aliphatic diisocyanates. In this paper, biocompatible segmented polyurethane elastomers were synthesized from aliphatic diisocyanates (1,4-diisocyanatobutane (BDI) and lysine methyl ester diisocyanate (LDI)), novel diurea diol chain extenders based on tyrosine and tyramine, and a model poly(ethylene glycol) (PEG) diol soft segment. The objectives were to design a hard segment similar in structure to that of MDI-based Polyurethanes and also investigate the effects of systematic changes in structure on mechanical and biological properties. The non-branched, symmetric polyurethane prepared from BDI and a tyramine-based chain extender had the highest modulus at 37 °C. Introduction of symmetric short-chain branches (SCBs) incorporated in the tyrosine-based chain extender lowered the modulus by an order of magnitude. Polyurethanes prepared from LDI were soft polymers that had a still lower modulus due to the asymmetric SCBs that hindered hard segment packing. Polyurethanes prepared from tyramine and tyrosine chain extenders thermally degraded at temperatures ranging from 110 to 150 °C, which are lower than that reported previously for phenyl urethanes. All four Polyurethanes supported the attachment, proliferation, and high viability of MG-63 human osteoblast-like cells in vitro. Therefore, the non-cytotoxic chemistry of these Polyurethanes make them good candidates for further development as biomedical implants.
-
synthesis of biocompatible segmented Polyurethanes from aliphatic diisocyanates and diurea diol chain extenders
Acta Biomaterialia, 2005Co-Authors: Scott A Guelcher, Katie M Gallagher, Jonathan E Didier, Derek B Klinedinst, John S Doctor, Aaron S Goldstein, Garth L Wilkes, Eric J Beckman, Jeffrey O HollingerAbstract:Many polyurethane elastomers display excellent mechanical properties and adequate biocompatibility. However, many medical-grade Polyurethanes are prepared from aromatic diisocyanates and can degrade in vivo to carcinogenic aromatic diamines, although the question of whether the concentrations of these harmful degradation products attain physiologically relevant levels is currently unresolved and strongly debated. It is therefore desirable to synthesize new medical-grade Polyurethanes from less toxic aliphatic diisocyanates. In this paper, biocompatible segmented polyurethane elastomers were synthesized from aliphatic diisocyanates (1,4-diisocyanatobutane (BDI) and lysine methyl ester diisocyanate (LDI)), novel diurea diol chain extenders based on tyrosine and tyramine, and a model poly(ethylene glycol) (PEG) diol soft segment. The objectives were to design a hard segment similar in structure to that of MDI-based Polyurethanes and also investigate the effects of systematic changes in structure on mechanical and biological properties. The non-branched, symmetric polyurethane prepared from BDI and a tyramine-based chain extender had the highest modulus at 37 degrees C. Introduction of symmetric short-chain branches (SCBs) incorporated in the tyrosine-based chain extender lowered the modulus by an order of magnitude. Polyurethanes prepared from LDI were soft polymers that had a still lower modulus due to the asymmetric SCBs that hindered hard segment packing. Polyurethanes prepared from tyramine and tyrosine chain extenders thermally degraded at temperatures ranging from 110 to 150 degrees C, which are lower than that reported previously for phenyl urethanes. All four Polyurethanes supported the attachment, proliferation, and high viability of MG-63 human osteoblast-like cells in vitro. Therefore, the non-cytotoxic chemistry of these Polyurethanes make them good candidates for further development as biomedical implants.
Xinling Wang - One of the best experts on this subject based on the ideXlab platform.
-
facile preparation of mussel inspired polyurethane hydrogel and its rapid curing behavior
ACS Applied Materials & Interfaces, 2014Co-Authors: Peiyu Sun, Jing Wang, Xiong Yao, Ying Peng, Zhen Zheng, Xinling WangAbstract:A facile method was found to incorporate a mussel-inspired adhesive moiety into synthetic polymers, and mussel mimetic Polyurethanes were developed as adhesive hydrogels. In these polymers, a urethane backbone was substituted for the polyamide chain of mussel adhesive proteins, and dopamine was appended to mimic the adhesive moiety of adhesive proteins. A series of mussel mimetic Polyurethanes were created through a step-growth polymerization based on hexamethylene diisocyanate as a hard segment, PEG having different molecular weights as a soft segment, and lysine-dopamine as a chain extender. Upon a treatment with Fe3+, the aqueous mussel mimetic polyurethane solutions can be triggered by pH adjustment to form adhesive hydrogels instantaneously; these materials can be used as injectable adhesive hydrogels. Upon a treatment with NaIO4, the mussel mimetic polyurethane solutions can be cured in a controllable period of time. The successful combination of the unique mussel-inspired adhesive moiety with a tun...
-
Facile Preparation of Mussel-Inspired Polyurethane Hydrogel and Its Rapid Curing Behavior
2014Co-Authors: Peiyu Sun, Jing Wang, Xiong Yao, Ying Peng, Zhen Zheng, Xinling WangAbstract:A facile method was found to incorporate a mussel-inspired adhesive moiety into synthetic polymers, and mussel mimetic Polyurethanes were developed as adhesive hydrogels. In these polymers, a urethane backbone was substituted for the polyamide chain of mussel adhesive proteins, and dopamine was appended to mimic the adhesive moiety of adhesive proteins. A series of mussel mimetic Polyurethanes were created through a step-growth polymerization based on hexamethylene diisocyanate as a hard segment, PEG having different molecular weights as a soft segment, and lysine-dopamine as a chain extender. Upon a treatment with Fe3+, the aqueous mussel mimetic polyurethane solutions can be triggered by pH adjustment to form adhesive hydrogels instantaneously; these materials can be used as injectable adhesive hydrogels. Upon a treatment with NaIO4, the mussel mimetic polyurethane solutions can be cured in a controllable period of time. The successful combination of the unique mussel-inspired adhesive moiety with a tunable polyurethane structure can result in a new kind of mussel-inspired adhesive polymers
Scott A Guelcher - One of the best experts on this subject based on the ideXlab platform.
-
synthesis of biocompatible segmented Polyurethanes from aliphatic diisocyanates and diurea diol chain extenders
Acta Biomaterialia, 2005Co-Authors: Scott A Guelcher, Katie M Gallagher, Jonathan E Didier, Derek B Klinedinst, John S Doctor, Aaron S Goldstein, Garth L Wilkes, Eric J Beckman, Jeffrey O HollingerAbstract:Abstract Many polyurethane elastomers display excellent mechanical properties and adequate biocompatibility. However, many medical-grade Polyurethanes are prepared from aromatic diisocyanates and can degrade in vivo to carcinogenic aromatic diamines, although the question of whether the concentrations of these harmful degradation products attain physiologically relevant levels is currently unresolved and strongly debated. It is therefore desirable to synthesize new medical-grade Polyurethanes from less toxic aliphatic diisocyanates. In this paper, biocompatible segmented polyurethane elastomers were synthesized from aliphatic diisocyanates (1,4-diisocyanatobutane (BDI) and lysine methyl ester diisocyanate (LDI)), novel diurea diol chain extenders based on tyrosine and tyramine, and a model poly(ethylene glycol) (PEG) diol soft segment. The objectives were to design a hard segment similar in structure to that of MDI-based Polyurethanes and also investigate the effects of systematic changes in structure on mechanical and biological properties. The non-branched, symmetric polyurethane prepared from BDI and a tyramine-based chain extender had the highest modulus at 37 °C. Introduction of symmetric short-chain branches (SCBs) incorporated in the tyrosine-based chain extender lowered the modulus by an order of magnitude. Polyurethanes prepared from LDI were soft polymers that had a still lower modulus due to the asymmetric SCBs that hindered hard segment packing. Polyurethanes prepared from tyramine and tyrosine chain extenders thermally degraded at temperatures ranging from 110 to 150 °C, which are lower than that reported previously for phenyl urethanes. All four Polyurethanes supported the attachment, proliferation, and high viability of MG-63 human osteoblast-like cells in vitro. Therefore, the non-cytotoxic chemistry of these Polyurethanes make them good candidates for further development as biomedical implants.
-
synthesis of biocompatible segmented Polyurethanes from aliphatic diisocyanates and diurea diol chain extenders
Acta Biomaterialia, 2005Co-Authors: Scott A Guelcher, Katie M Gallagher, Jonathan E Didier, Derek B Klinedinst, John S Doctor, Aaron S Goldstein, Garth L Wilkes, Eric J Beckman, Jeffrey O HollingerAbstract:Many polyurethane elastomers display excellent mechanical properties and adequate biocompatibility. However, many medical-grade Polyurethanes are prepared from aromatic diisocyanates and can degrade in vivo to carcinogenic aromatic diamines, although the question of whether the concentrations of these harmful degradation products attain physiologically relevant levels is currently unresolved and strongly debated. It is therefore desirable to synthesize new medical-grade Polyurethanes from less toxic aliphatic diisocyanates. In this paper, biocompatible segmented polyurethane elastomers were synthesized from aliphatic diisocyanates (1,4-diisocyanatobutane (BDI) and lysine methyl ester diisocyanate (LDI)), novel diurea diol chain extenders based on tyrosine and tyramine, and a model poly(ethylene glycol) (PEG) diol soft segment. The objectives were to design a hard segment similar in structure to that of MDI-based Polyurethanes and also investigate the effects of systematic changes in structure on mechanical and biological properties. The non-branched, symmetric polyurethane prepared from BDI and a tyramine-based chain extender had the highest modulus at 37 degrees C. Introduction of symmetric short-chain branches (SCBs) incorporated in the tyrosine-based chain extender lowered the modulus by an order of magnitude. Polyurethanes prepared from LDI were soft polymers that had a still lower modulus due to the asymmetric SCBs that hindered hard segment packing. Polyurethanes prepared from tyramine and tyrosine chain extenders thermally degraded at temperatures ranging from 110 to 150 degrees C, which are lower than that reported previously for phenyl urethanes. All four Polyurethanes supported the attachment, proliferation, and high viability of MG-63 human osteoblast-like cells in vitro. Therefore, the non-cytotoxic chemistry of these Polyurethanes make them good candidates for further development as biomedical implants.
Qiang Fu - One of the best experts on this subject based on the ideXlab platform.
-
biodegradable multiblock polyurethane micelles with tunable reduction sensitivity for on demand intracellular drug delivery
RSC Advances, 2014Co-Authors: Xueling He, Qiang Fu, Jiehua Li, Mingming Ding, Liang LiAbstract:Redox-responsive nanovehicles containing disulfide bonds are particularly promising for targeted intracellular drug delivery. However, conventional reduction-sensitive nanocarriers generally lack control of stimuli-responsiveness due to their poor structural tunability. In this study, we developed a class of biodegradable multiblock Polyurethanes bearing varied amounts of disulfide linkages in their backbone. The reducible Polyurethanes exhibit interesting phase behavior and self-assembly properties, as well as triggered release profiles under an intracellular reduction-mimicking environment. It was found that the redox-sensitive polyurethane micelles can rapidly enter tumor cells and efficiently transport the encapsulated payloads into the cytosol. In vitro cytotoxicity studies demonstrated that the paclitaxel-loaded polyurethane micelles could inhibit the proliferation of tumor cells effectively, with the inhibition effects controlled by adjusting the disulfide content in the polymeric backbone. In addition, the drug-free nanomicelles possess good cytocompatibility toward both cancer cells and healthy cells. These multiblock bioresponsive Polyurethanes hold great promise in the further development of controllable intracellular drug transporters.
-
synthesis and characterization of ph sensitive biodegradable polyurethane for potential drug delivery applications
Macromolecules, 2011Co-Authors: Lijuan Zhou, Lunquan Yu, Jiehua Li, Zhigao Wang, Mingming Ding, Qiang FuAbstract:To obtain a pH-sensitive multifunctional polyurethane micelle drug carrier, a novel pH-sensitive macrodiol containing acid-cleavable hydrazone linkers, poly(e-caprolactone)−hydrazone−poly(ethylene glycol)−hydrazone−poly(e-caprolactone) diol (PCL−Hyd−PEG−Hyd−PCL), was synthesized and characterized with proton nuclear magnetic resonance spectra (1H NMR). A series of pH-sensitive biodegradable Polyurethanes (pHPUs) were designed and synthesized using pH-sensitive macrodiol, l-lysine ethyl ester diisocyanate (LDI) and l-lysine derivative tripeptide as chain extender, which can provide an active reaction site for the development of positive target polyurethane micelles for drug delivery. The bulk structures of the prepared Polyurethanes were carefully characterized with 1H NMR, gel permeation chromatograph (GPC), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR). The Polyurethanes could be cleaved in acidic media (pH ∼ 4−6) as well as degraded in PBS and enzymatic solu...
Garth L Wilkes - One of the best experts on this subject based on the ideXlab platform.
-
synthesis of biocompatible segmented Polyurethanes from aliphatic diisocyanates and diurea diol chain extenders
Acta Biomaterialia, 2005Co-Authors: Scott A Guelcher, Katie M Gallagher, Jonathan E Didier, Derek B Klinedinst, John S Doctor, Aaron S Goldstein, Garth L Wilkes, Eric J Beckman, Jeffrey O HollingerAbstract:Abstract Many polyurethane elastomers display excellent mechanical properties and adequate biocompatibility. However, many medical-grade Polyurethanes are prepared from aromatic diisocyanates and can degrade in vivo to carcinogenic aromatic diamines, although the question of whether the concentrations of these harmful degradation products attain physiologically relevant levels is currently unresolved and strongly debated. It is therefore desirable to synthesize new medical-grade Polyurethanes from less toxic aliphatic diisocyanates. In this paper, biocompatible segmented polyurethane elastomers were synthesized from aliphatic diisocyanates (1,4-diisocyanatobutane (BDI) and lysine methyl ester diisocyanate (LDI)), novel diurea diol chain extenders based on tyrosine and tyramine, and a model poly(ethylene glycol) (PEG) diol soft segment. The objectives were to design a hard segment similar in structure to that of MDI-based Polyurethanes and also investigate the effects of systematic changes in structure on mechanical and biological properties. The non-branched, symmetric polyurethane prepared from BDI and a tyramine-based chain extender had the highest modulus at 37 °C. Introduction of symmetric short-chain branches (SCBs) incorporated in the tyrosine-based chain extender lowered the modulus by an order of magnitude. Polyurethanes prepared from LDI were soft polymers that had a still lower modulus due to the asymmetric SCBs that hindered hard segment packing. Polyurethanes prepared from tyramine and tyrosine chain extenders thermally degraded at temperatures ranging from 110 to 150 °C, which are lower than that reported previously for phenyl urethanes. All four Polyurethanes supported the attachment, proliferation, and high viability of MG-63 human osteoblast-like cells in vitro. Therefore, the non-cytotoxic chemistry of these Polyurethanes make them good candidates for further development as biomedical implants.
-
synthesis of biocompatible segmented Polyurethanes from aliphatic diisocyanates and diurea diol chain extenders
Acta Biomaterialia, 2005Co-Authors: Scott A Guelcher, Katie M Gallagher, Jonathan E Didier, Derek B Klinedinst, John S Doctor, Aaron S Goldstein, Garth L Wilkes, Eric J Beckman, Jeffrey O HollingerAbstract:Many polyurethane elastomers display excellent mechanical properties and adequate biocompatibility. However, many medical-grade Polyurethanes are prepared from aromatic diisocyanates and can degrade in vivo to carcinogenic aromatic diamines, although the question of whether the concentrations of these harmful degradation products attain physiologically relevant levels is currently unresolved and strongly debated. It is therefore desirable to synthesize new medical-grade Polyurethanes from less toxic aliphatic diisocyanates. In this paper, biocompatible segmented polyurethane elastomers were synthesized from aliphatic diisocyanates (1,4-diisocyanatobutane (BDI) and lysine methyl ester diisocyanate (LDI)), novel diurea diol chain extenders based on tyrosine and tyramine, and a model poly(ethylene glycol) (PEG) diol soft segment. The objectives were to design a hard segment similar in structure to that of MDI-based Polyurethanes and also investigate the effects of systematic changes in structure on mechanical and biological properties. The non-branched, symmetric polyurethane prepared from BDI and a tyramine-based chain extender had the highest modulus at 37 degrees C. Introduction of symmetric short-chain branches (SCBs) incorporated in the tyrosine-based chain extender lowered the modulus by an order of magnitude. Polyurethanes prepared from LDI were soft polymers that had a still lower modulus due to the asymmetric SCBs that hindered hard segment packing. Polyurethanes prepared from tyramine and tyrosine chain extenders thermally degraded at temperatures ranging from 110 to 150 degrees C, which are lower than that reported previously for phenyl urethanes. All four Polyurethanes supported the attachment, proliferation, and high viability of MG-63 human osteoblast-like cells in vitro. Therefore, the non-cytotoxic chemistry of these Polyurethanes make them good candidates for further development as biomedical implants.
