Thermomechanical properties of polyurethanes（PUs） strongly depend on the molecular interactions and microphase structure. In this work, two chain extenders with different ratios, flexile 1,4-butanediol（BDO） and br...Thermomechanical properties of polyurethanes（PUs） strongly depend on the molecular interactions and microphase structure. In this work, two chain extenders with different ratios, flexile 1,4-butanediol（BDO） and branched trimethylolpropane mono allyl ether（TMPAE）, are used to tune the molecular interactions and microphase structures of a series of biodegradable thermoplastic polyurethanes（TPUs）. In TPUs, the biodegradable polycaprolactone（PCL, M_n of 2000） is used as soft segment while 1,6-diisocyanatohexane（HDI） and chain extenders are used as hard segment. Fourier transform infrared spectroscopy（FTIR）, proton nuclear magnetic resonance spectroscppy（~1 H-NMR）, gel permeation chromatography（GPC）, differential scanning calorimetry（DSC）, dynamic mechanical analysis（DMA） and mechanical tests were performed to characterize the bulk structure and properties of TPUs. Compared with BDO, the steric bulk of TMPAE is larger. The increment of TMPAE can help to increase the hydrogen bond content, microphase separation, and the elastic modulus ratio（R）, which would strongly affect the thermomechanical property of the TPUs. The results of this work verify the importance of the structure of chain extender on the properties of TPUs. It provides valuable information for further understanding the structure-property relationships of these polyurethanes.展开更多
Polyurethane micelles（PM）-based nanovehicles have shown great potential in targeted delivery of therapeutics and diagnostics into tumors.However,the pathways of PMs entering cancer cells and the action mechanism of ...Polyurethane micelles（PM）-based nanovehicles have shown great potential in targeted delivery of therapeutics and diagnostics into tumors.However,the pathways of PMs entering cancer cells and the action mechanism of targeting ligands have yet to be understood.In this contribution,the actively-targeted PM were developed using trastuzumab as a model targeting group.It was found that PM were mainly taken up by SKOV-3 tumor cells via a micropinocytosis process,while the incorporation of trastuzumab to PM enabled a receptor-mediated endocytosis of nanocarriers in cancer cells,leading to more efficient cell entry and enhanced anticancer efficacy of chemotherapeutic drugs both in vitro and in vivo.This study is advantageous to the understanding of the action mechanism of trastuzumab,and significant for the construction of improved formulations for targeted delivery and precise therapy.展开更多
基金financially supported by the National Natural Science Foundation of China (No. 51573114)the National Science Fund for Distinguished Young Scholars of China (No. 51425305)the Project of State Key Laboratory of Polymer Materials Engineering (Sichuan University) (No. SKLPME 2016-2-04)
文摘Thermomechanical properties of polyurethanes（PUs） strongly depend on the molecular interactions and microphase structure. In this work, two chain extenders with different ratios, flexile 1,4-butanediol（BDO） and branched trimethylolpropane mono allyl ether（TMPAE）, are used to tune the molecular interactions and microphase structures of a series of biodegradable thermoplastic polyurethanes（TPUs）. In TPUs, the biodegradable polycaprolactone（PCL, M_n of 2000） is used as soft segment while 1,6-diisocyanatohexane（HDI） and chain extenders are used as hard segment. Fourier transform infrared spectroscopy（FTIR）, proton nuclear magnetic resonance spectroscppy（~1 H-NMR）, gel permeation chromatography（GPC）, differential scanning calorimetry（DSC）, dynamic mechanical analysis（DMA） and mechanical tests were performed to characterize the bulk structure and properties of TPUs. Compared with BDO, the steric bulk of TMPAE is larger. The increment of TMPAE can help to increase the hydrogen bond content, microphase separation, and the elastic modulus ratio（R）, which would strongly affect the thermomechanical property of the TPUs. The results of this work verify the importance of the structure of chain extender on the properties of TPUs. It provides valuable information for further understanding the structure-property relationships of these polyurethanes.
基金financially supported by the National Natural Science Foundation of China(Nos.51273126 and 51573112)the National Science Fund for Distinguished Young Scholars of China(No.51425305)the Youth Science and Technology Innovation Team of Sichuan Province(No.2015TD0001)
文摘Polyurethane micelles（PM）-based nanovehicles have shown great potential in targeted delivery of therapeutics and diagnostics into tumors.However,the pathways of PMs entering cancer cells and the action mechanism of targeting ligands have yet to be understood.In this contribution,the actively-targeted PM were developed using trastuzumab as a model targeting group.It was found that PM were mainly taken up by SKOV-3 tumor cells via a micropinocytosis process,while the incorporation of trastuzumab to PM enabled a receptor-mediated endocytosis of nanocarriers in cancer cells,leading to more efficient cell entry and enhanced anticancer efficacy of chemotherapeutic drugs both in vitro and in vivo.This study is advantageous to the understanding of the action mechanism of trastuzumab,and significant for the construction of improved formulations for targeted delivery and precise therapy.
