The crystallization kinetics of semicrystalline polymers is often studied with isothermal experiments and analyzed by fitting the data with analytical expressions of the Avrami and Lauritzen and Hoffman(LH)theories.To...The crystallization kinetics of semicrystalline polymers is often studied with isothermal experiments and analyzed by fitting the data with analytical expressions of the Avrami and Lauritzen and Hoffman(LH)theories.To correctly carry out the analysis,precautions in both experiments and data fitting should be taken.Here,we systematically discussed the factors that influence the validity of the crystallization kinetics study.The basic concepts and fundamentals of the Avrami and LH theories were introduced at first.Then,experimental protocols were discussed in detail.To clarify the impact of various experimental parameters,selected common polymers,i.e.,polypropylene and polylactide,were studied using various experimental techniques(i.e.,differential scanning calorimetry and polarized light optical microscopy).Common mistakes were simulated under conditions when non-ideal experimental parameters were applied.Furthermore,from a practical point of view,we show how to fit the experimental data to the Avrami and the LH theories,using an Origin■App developed by us.展开更多
Melt extrusion-based additive manufacturing(ME-AM)is a promising technique to fabricate porous scaffolds for tissue engi-neering applications.However,most synthetic semicrystalline polymers do not possess the intrinsi...Melt extrusion-based additive manufacturing(ME-AM)is a promising technique to fabricate porous scaffolds for tissue engi-neering applications.However,most synthetic semicrystalline polymers do not possess the intrinsic biological activity required to control cell fate.Grafting of biomolecules on polymeric surfaces of AM scaffolds enhances the bioactivity of a construct;however,there are limited strategies available to control the surface density.Here,we report a strategy to tune the surface density of bioactive groups by blending a low molecular weight poly(ε-caprolactone)5k(PCL5k)containing orthogonally reactive azide groups with an unfunctionalized high molecular weight PCL75k at different ratios.Stable porous three-dimensional(3D)scaf-folds were then fabricated using a high weight percentage(75 wt.%)of the low molecular weight PCL 5k.As a proof-of-concept test,we prepared films of three different mass ratios of low and high molecular weight polymers with a thermopress and reacted with an alkynated fluorescent model compound on the surface,yielding a density of 201-561 pmol/cm^(2).Subsequently,a bone morphogenetic protein 2(BMP-2)-derived peptide was grafted onto the films comprising different blend compositions,and the effect of peptide surface density on the osteogenic differentiation of human mesenchymal stromal cells(hMSCs)was assessed.After two weeks of culturing in a basic medium,cells expressed higher levels of BMP receptor II(BMPRII)on films with the conjugated peptide.In addition,we found that alkaline phosphatase activity was only significantly enhanced on films contain-ing the highest peptide density(i.e.,561 pmol/cm^(2)),indicating the importance of the surface density.Taken together,these results emphasize that the density of surface peptides on cell differentiation must be considered at the cell-material interface.Moreover,we have presented a viable strategy for ME-AM community that desires to tune the bulk and surface functionality via blending of(modified)polymers.Furthermore,the use of alkyne-azide“click”chemistry enables spatial control over bioconjugation of many tissue-specific moieties,making this approach a versatile strategy for tissue engineering applications.展开更多
Mixed Sn-Pb perovskites are attracting significant attention due to their narrow bandgap and consequent potential for all-perovskite tandem solar cells.However,the conventional hole transport materials can lead to ban...Mixed Sn-Pb perovskites are attracting significant attention due to their narrow bandgap and consequent potential for all-perovskite tandem solar cells.However,the conventional hole transport materials can lead to band misalignment or induce degradation at the buried interface of perovskite.Here we designed a self-assembled material 4-(9H-carbozol-9-yl)phenylboronic acid(4PBA)for the surface modification of the substrate as the hole-selective contact.It incorporates an electron-rich carbazole group and conjugated phenyl group,which contribute to a substantial interfacial dipole moment and tune the substrate’s energy levels for better alignment with the Sn-Pb perovskite energy levels,thereby promoting hole extraction.Meanwhile,enhanced perovskite crystallization and improved contact at bottom of the perovskite minimized defects within perovskite bulk and at the buried interface,suppressing non-radiative recombination.Consequently,Sn-Pb perovskite solar cells using 4PBA achieved efficiencies of up to 23.45%.Remarkably,the 4PBA layer provided superior interfacial chemical stability,and effectively mitigated device degradation.Unencapsulated devices retained 93.5%of their initial efficiency after 2000 h of shelf storage.展开更多
Capillary hydrodynamic fractionation（CHDF） with turbidity detection at a single wavelength is an analytical technique that is often used for sizing the sub-micrometric particles of hydrophobic colloids.This article ...Capillary hydrodynamic fractionation（CHDF） with turbidity detection at a single wavelength is an analytical technique that is often used for sizing the sub-micrometric particles of hydrophobic colloids.This article investigates three sources of errors that affect the particle size distribution（PSD） estimated by CHDF：diameter calibration errors,uncertainties in the particle refractive index（PRI）,and instrumental broadening（IB）.The study is based on simulated and experimental examples that involve unimodal and bimodal PSDs.Small errors in the diameter calibration curve can produce important deviations in the number average diameter due to systematic shifts suffered by the PSD modes.Moderate uncertainties in the PRI are unimportant in the analysis of unimodal PSDs,but in the specific case of bimodal PSDs,errors in the PRI can strongly affect the estimated number concentration of each mode.The typical IB correction（based on the IB function estimated from narrow standards） produces slightly erroneous average diameters but can lead to PSDs with underestimated widths and distorted shapes.In practice,the three investigated sources of errors can be present simultaneously,and uncertainties in the average diameters,the shape and width of the PSD,and the number concentration of the PSD modes are unavoidable.展开更多
Intrauterine adhesion (IUA) is the fibrosis within the uterine cavity. It is the second most common cause of female infertility, significantly affecting women’s physical and mental health. Current treatment strategie...Intrauterine adhesion (IUA) is the fibrosis within the uterine cavity. It is the second most common cause of female infertility, significantly affecting women’s physical and mental health. Current treatment strategies fail to provide a satisfactory therapeutic outcome for IUA patients, leaving an enormous challenge for reproductive science. A self-healing adhesive hydrogel with antioxidant properties will be highly helpful in IUA prevention. In this work, we prepare a series of self-healing hydrogels (P10G15, P10G20, and P10G25) with antioxidant and adhesive properties. Those hydrogels exhibit good self-healing properties and can adapt themselves to different structures. They possess good injectability and fit the shape of the human uterus. Moreover, the hydrogels exhibit good tissue adhesiveness, which is desirable for stable retention and therapeutic efficacy. The in vitro experiments using P10G20 show that the adhesive effectively scavenges ABTS+, DPPH, and hydroxyl radicals, rescuing cells from oxidative stress. In addition, P10G20 offers good hemocompatibility and in vitro and in vivo biocompatibility. Furthermore, P10G20 lowers down the in vivo oxidative stress and prevents IUA with less fibrotic tissue and better endometrial regeneration in the animal model. It can effectively downregulate fibrosis-related transforming growth factor beta 1 (TGF-β1) and vascular endothelial growth factor (VEGF). Altogether, these adhesives may be a good alternative for the clinical treatment of intrauterine adhesion.展开更多
基金financially supported by the the National Natural Science Foundation of China (Nos.21922308 and 51820105005)the National Key R&D Program of China (No.2017YFE0117800)+3 种基金the financial support from the BIODEST projectfunding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No.778092The funding of MICINN (Spain) through grant PID2020-113045GB-C21 is gratefully acknowledgedthe Youth Innovation Promotion Association of the Chinese Academy of Sciences (No.Y201908)
文摘The crystallization kinetics of semicrystalline polymers is often studied with isothermal experiments and analyzed by fitting the data with analytical expressions of the Avrami and Lauritzen and Hoffman(LH)theories.To correctly carry out the analysis,precautions in both experiments and data fitting should be taken.Here,we systematically discussed the factors that influence the validity of the crystallization kinetics study.The basic concepts and fundamentals of the Avrami and LH theories were introduced at first.Then,experimental protocols were discussed in detail.To clarify the impact of various experimental parameters,selected common polymers,i.e.,polypropylene and polylactide,were studied using various experimental techniques(i.e.,differential scanning calorimetry and polarized light optical microscopy).Common mistakes were simulated under conditions when non-ideal experimental parameters were applied.Furthermore,from a practical point of view,we show how to fit the experimental data to the Avrami and the LH theories,using an Origin■App developed by us.
基金the European Research Council starting grant “Cell Hybridge” for financial support under the Horizon2020 framework program (Grant#637308)the Province of Limburg for support and funding
文摘Melt extrusion-based additive manufacturing(ME-AM)is a promising technique to fabricate porous scaffolds for tissue engi-neering applications.However,most synthetic semicrystalline polymers do not possess the intrinsic biological activity required to control cell fate.Grafting of biomolecules on polymeric surfaces of AM scaffolds enhances the bioactivity of a construct;however,there are limited strategies available to control the surface density.Here,we report a strategy to tune the surface density of bioactive groups by blending a low molecular weight poly(ε-caprolactone)5k(PCL5k)containing orthogonally reactive azide groups with an unfunctionalized high molecular weight PCL75k at different ratios.Stable porous three-dimensional(3D)scaf-folds were then fabricated using a high weight percentage(75 wt.%)of the low molecular weight PCL 5k.As a proof-of-concept test,we prepared films of three different mass ratios of low and high molecular weight polymers with a thermopress and reacted with an alkynated fluorescent model compound on the surface,yielding a density of 201-561 pmol/cm^(2).Subsequently,a bone morphogenetic protein 2(BMP-2)-derived peptide was grafted onto the films comprising different blend compositions,and the effect of peptide surface density on the osteogenic differentiation of human mesenchymal stromal cells(hMSCs)was assessed.After two weeks of culturing in a basic medium,cells expressed higher levels of BMP receptor II(BMPRII)on films with the conjugated peptide.In addition,we found that alkaline phosphatase activity was only significantly enhanced on films contain-ing the highest peptide density(i.e.,561 pmol/cm^(2)),indicating the importance of the surface density.Taken together,these results emphasize that the density of surface peptides on cell differentiation must be considered at the cell-material interface.Moreover,we have presented a viable strategy for ME-AM community that desires to tune the bulk and surface functionality via blending of(modified)polymers.Furthermore,the use of alkyne-azide“click”chemistry enables spatial control over bioconjugation of many tissue-specific moieties,making this approach a versatile strategy for tissue engineering applications.
基金supported by the Joint Fund of Provincial Science and Technology Research and Development Plan of Henan Province(232301420004)and the Outstanding Youth Fund of the Natural Science Foundation of Henan Province(242300421069)the Energy for future-E4F Postdoctoral fellowship program MSCA-COFUND(101034297).
文摘Mixed Sn-Pb perovskites are attracting significant attention due to their narrow bandgap and consequent potential for all-perovskite tandem solar cells.However,the conventional hole transport materials can lead to band misalignment or induce degradation at the buried interface of perovskite.Here we designed a self-assembled material 4-(9H-carbozol-9-yl)phenylboronic acid(4PBA)for the surface modification of the substrate as the hole-selective contact.It incorporates an electron-rich carbazole group and conjugated phenyl group,which contribute to a substantial interfacial dipole moment and tune the substrate’s energy levels for better alignment with the Sn-Pb perovskite energy levels,thereby promoting hole extraction.Meanwhile,enhanced perovskite crystallization and improved contact at bottom of the perovskite minimized defects within perovskite bulk and at the buried interface,suppressing non-radiative recombination.Consequently,Sn-Pb perovskite solar cells using 4PBA achieved efficiencies of up to 23.45%.Remarkably,the 4PBA layer provided superior interfacial chemical stability,and effectively mitigated device degradation.Unencapsulated devices retained 93.5%of their initial efficiency after 2000 h of shelf storage.
基金the financial support from CONICET,Universidad Nacional del Litoral,Universidad Tecnologica Nacional,Secretaria de Politicas Universitarias(Argentina)the financial support from the Basque Government(GV-IT-303-10)Ministerio de Ciencia e Innovacion(MICINN,Ref.CTQ2011-25572)and UPV/EHU(UFI 11/56)
文摘Capillary hydrodynamic fractionation（CHDF） with turbidity detection at a single wavelength is an analytical technique that is often used for sizing the sub-micrometric particles of hydrophobic colloids.This article investigates three sources of errors that affect the particle size distribution（PSD） estimated by CHDF：diameter calibration errors,uncertainties in the particle refractive index（PRI）,and instrumental broadening（IB）.The study is based on simulated and experimental examples that involve unimodal and bimodal PSDs.Small errors in the diameter calibration curve can produce important deviations in the number average diameter due to systematic shifts suffered by the PSD modes.Moderate uncertainties in the PRI are unimportant in the analysis of unimodal PSDs,but in the specific case of bimodal PSDs,errors in the PRI can strongly affect the estimated number concentration of each mode.The typical IB correction（based on the IB function estimated from narrow standards） produces slightly erroneous average diameters but can lead to PSDs with underestimated widths and distorted shapes.In practice,the three investigated sources of errors can be present simultaneously,and uncertainties in the average diameters,the shape and width of the PSD,and the number concentration of the PSD modes are unavoidable.
基金supported by the National Natural Science Foundation of China(52103184,81660265,81960276)Natural Science Foundation of Jiangxi Province(20224BAB206026)+1 种基金Key Research and Development Program of Jiangxi Province(20202BBGL73065)Funding for Basic Scientific Research and‘Young Talent Support Plan’of Xi’an Jiaotong University(xzy012022038).
文摘Intrauterine adhesion (IUA) is the fibrosis within the uterine cavity. It is the second most common cause of female infertility, significantly affecting women’s physical and mental health. Current treatment strategies fail to provide a satisfactory therapeutic outcome for IUA patients, leaving an enormous challenge for reproductive science. A self-healing adhesive hydrogel with antioxidant properties will be highly helpful in IUA prevention. In this work, we prepare a series of self-healing hydrogels (P10G15, P10G20, and P10G25) with antioxidant and adhesive properties. Those hydrogels exhibit good self-healing properties and can adapt themselves to different structures. They possess good injectability and fit the shape of the human uterus. Moreover, the hydrogels exhibit good tissue adhesiveness, which is desirable for stable retention and therapeutic efficacy. The in vitro experiments using P10G20 show that the adhesive effectively scavenges ABTS+, DPPH, and hydroxyl radicals, rescuing cells from oxidative stress. In addition, P10G20 offers good hemocompatibility and in vitro and in vivo biocompatibility. Furthermore, P10G20 lowers down the in vivo oxidative stress and prevents IUA with less fibrotic tissue and better endometrial regeneration in the animal model. It can effectively downregulate fibrosis-related transforming growth factor beta 1 (TGF-β1) and vascular endothelial growth factor (VEGF). Altogether, these adhesives may be a good alternative for the clinical treatment of intrauterine adhesion.
