The resonance light-scattering (RLS) of human serum albumin (HSA) and bovine serum albumin (BSA) is reported for the first time, and applied to study photochemical reaction of HSA and BSA. The fact of photocrosslinkin...The resonance light-scattering (RLS) of human serum albumin (HSA) and bovine serum albumin (BSA) is reported for the first time, and applied to study photochemical reaction of HSA and BSA. The fact of photocrosslinking self-association effect in HSA and BSA solutions is identified by the enhancement of RLS. The fluorescence quenching at about 350 nm and 700 nm proves that tryptophan (Trp) residues are one of the photochemical activity sites in HSA and BSA molecules. The Rayleigh scattering (RS) spectra of HSA and BSA that were neglected in fluorescence spectra before are found at about 296 nm, 592 nm and 888 nm for the first time, and are of adventageous to studying the aggregation of HSA or BSA. The possible photochemical reaction mechanism is also proposed.展开更多
The recent developments in the photoinitiated cross-linking of polyethylene and the significant breakthrough of its industrial application are reviewed. The enhanced photo-initiation system, the dynamics of photoiniti...The recent developments in the photoinitiated cross-linking of polyethylene and the significant breakthrough of its industrial application are reviewed. The enhanced photo-initiation system, the dynamics of photoinitiated crosslinking, the optimum conditions, the crystal morphological structures and related properties, and the photo- and thermo-oxidation stability of photocrosslinked polyethylene (XLPE) materials have been elucidated systematically. A new technique for producing photocrosslinked XLPE-insulated wire and cable is described in detail. It can be expected that the future applications of photocrosslinking technique of polyolefins will be very promising.展开更多
Three-dimensional(3D)hydrogel models play a crucial role in tissue engineering for promoting tissue regeneration.A biomimetic microchannel network system in the 3D hydrogel model is necessary for optimal cellular func...Three-dimensional(3D)hydrogel models play a crucial role in tissue engineering for promoting tissue regeneration.A biomimetic microchannel network system in the 3D hydrogel model is necessary for optimal cellular function.This report describes the preparation of a biomimetic hydrogel scaffold with an internal microchannel network,using electrospinning techniques and the sacrificial template method for 3D cell culture.Microchannels and cavities were created within the gelatin methacryloyl(GelMA)hydrogel by sacrificing polyvinyl alcohol(PVA)electrospun fibers(>10µm),resulting in the creation of microvessel-like channels.Mechanical characterizations,swelling properties,and biodegradation analysis were conducted to investigate the feasibility of a biomimetic microchannel network hydrogel scaffold for 3D cell culture applications.Compared to pure GelMA hydrogel,the hydrogel with microchannels promoted cell proliferation,adhesion,and endothelial tube formation.Moreover,the results confirmed that the biomimetic microchannel network scaffold had a major impact on the distribution and arrangement of human umbilical vein endothelial cells(HUVECs)and can enable the formation of artificial microvasculature by the culture of HUVECs and cell media perfusion.展开更多
This study presents a simple and robust three-dimensional human hepatic tissue model to emulate steatotic and fibrotic conditions and provide an in vitro model for drug testing and mechanistic studies.Using a photolit...This study presents a simple and robust three-dimensional human hepatic tissue model to emulate steatotic and fibrotic conditions and provide an in vitro model for drug testing and mechanistic studies.Using a photolithographic biofabrication method with a photomask featuring hexagonal units,liver cells,including a human hepatic cell line(HepG2-C3A)and a human hepatic stellate cell line(LX-2)were embedded in gelatin methacryloyl hydrogel.Hepatic steatosis was induced by supraphysiological concentration of free fatty acids;hepatic fibrosis was induced by transforming growth factor-β1.Induction of steatosis was confirmed by Oil Red O and BODIPY staining and was inhibited with toyocamycin and obeticholic acid.Induction of fibrosis was confirmed by immunostaining for collagen type I and alpha smooth muscle actin and inhibited by rapamycin and curcumin treatment.This model was further preliminarily validated using primary human hepatocytes in a similar setup.These constructs provide a viable,biologically relevant,and higher throughput model of hepatic steatosis and fibrosis and may facilitate the study of the mechanisms of disease and testing of liver-directed drugs.展开更多
New water soluble and photocrosslinkable prepolymers containing acrylate and quaternary ammonium salt groups were synthesized from epoxy phenolic resin via ring-opening reaction with acrylic acid and with aqueous solu...New water soluble and photocrosslinkable prepolymers containing acrylate and quaternary ammonium salt groups were synthesized from epoxy phenolic resin via ring-opening reaction with acrylic acid and with aqueous solution of triethylamine hydrochloride successively. The second reaction needs no phase transfer catalyst to accelerate, since the product formed can act as a phase transfer catalyst. The prepolymer obtained contains both photocrosslinkable acrylate groups and hydrophilic quaternary ammonium salt groups. Optimum conditions for these reactions were studied. The photosensitivity of the prepolymer was also investigated. The effects of different photoinitiators, different crosslinkable diluent monomers and amine accelerator on the photosensitivity of the prepolymer were compared. The photoinitiator of hydrogen abstraction type is still effective without using amine or alcohol as accelerator, because the prepolymer contains a H beside the OH groups formed in the ring-opening reactions.展开更多
Controlled drug delivery holds great potential for effective tumor treatment owing to the merits of overcoming drug resistance and improving therapeutic efficacy while minimizing systemic toxicity.However,accurate and...Controlled drug delivery holds great potential for effective tumor treatment owing to the merits of overcoming drug resistance and improving therapeutic efficacy while minimizing systemic toxicity.However,accurate and controllable delivery of chemotherapeutics into tumor tissue with high efficiency remains a huge challenge.Taking advantage of the UV-emitting characteristics of upconversion nanoparticles(UCNPs),herein we for the first time report an MMP-2 enzyme and near infrared(NIR)dual-mediated sequential drug delivery and in-situ immobilization(ENDDI)system that is fabricated by decorating UCNPs with MMP-2 responsive and photocrosslinkable peptide bearing anticancer drug doxorubicin(DOX)for overcoming multidrug resistance.Upon cleavage with tumor-specific MMP-2,the peptide fragment containing a photolabile benzophenone(BP)and DOX could be released and in-situ immobilized within the tumor through the covalent crosslinking reaction between BP and neighboring biomolecules under the excitation of converted UVemission from UCNPs,which remarkably blocks the exocytosis of DOX leading to prolonged drug retention,achieving significant suppression of DOX-resistant breast tumors.Our current dual stimuli-mediated sequential drug delivery and in-situ immobilization represent a generalizable strategy for the effective treatment of multidrug resistant tumors.展开更多
Photoinitiated crosslinking of ethylene-propylene-diene terpolymer （EPDM） blends filled with calcium carbonate, talc and calcined kaolin （CK） in the presence of benzil dimethyl ketal as photoinitiator and trimethy...Photoinitiated crosslinking of ethylene-propylene-diene terpolymer （EPDM） blends filled with calcium carbonate, talc and calcined kaolin （CK） in the presence of benzil dimethyl ketal as photoinitiator and trimethylolpropane triacrylate as crosslinker and their related properties have been studied by different analytical methods, The results from gel content and heat extension determination show that the efficiency ofphotocrosslinking of EPDM increases with increasing the content of diene and its molecular weight. The EPDM blends with 100 phr different inorganic fillers can be photocrosslinked to gel content of above 60% by 5 s UV-irradiation under optimum conditions. Under the same conditions of irradiation, the orders of photocrosslinking rate and final gel content are EPDM/CaCO3 〉 EPDM/talc 〉 EPDM/CK. The data from thermogravimetric analysis, dynamic mechanical thermal analysis, electrical properties, mechanical tests and scanning electron microscopy show that UV irradiation crosslinking apparently enhances the thermal stability, mechanical properties and electrical properties of the photocrosslinked EPDM/inorganic filler samples. Although the attenuated total-reflection FTIR data show that inorganic fillers can promote the surface photo-oxidation of EPDM/inorganic filler samples with increasing the irradiation time, the above related properties of the photocrosslinked EPDM blends irradiated within 5 s are enough to satisfy many applications in the cable industry.展开更多
基金the National Natural Science Foundation of China ! 29961001the Foundation for Talents Striding across the Century of Guangxi
文摘The resonance light-scattering (RLS) of human serum albumin (HSA) and bovine serum albumin (BSA) is reported for the first time, and applied to study photochemical reaction of HSA and BSA. The fact of photocrosslinking self-association effect in HSA and BSA solutions is identified by the enhancement of RLS. The fluorescence quenching at about 350 nm and 700 nm proves that tryptophan (Trp) residues are one of the photochemical activity sites in HSA and BSA molecules. The Rayleigh scattering (RS) spectra of HSA and BSA that were neglected in fluorescence spectra before are found at about 296 nm, 592 nm and 888 nm for the first time, and are of adventageous to studying the aggregation of HSA or BSA. The possible photochemical reaction mechanism is also proposed.
基金The project was successively supported by the National Natural Science Foundation of China(No. 5880104, No. 59543002 and No. 59773030).
文摘The recent developments in the photoinitiated cross-linking of polyethylene and the significant breakthrough of its industrial application are reviewed. The enhanced photo-initiation system, the dynamics of photoinitiated crosslinking, the optimum conditions, the crystal morphological structures and related properties, and the photo- and thermo-oxidation stability of photocrosslinked polyethylene (XLPE) materials have been elucidated systematically. A new technique for producing photocrosslinked XLPE-insulated wire and cable is described in detail. It can be expected that the future applications of photocrosslinking technique of polyolefins will be very promising.
基金supported by the National Natural Science Foundation of China(No.31870934)the Natural Science Foundation for Young Scientists of Shanxi Province(No.202103021223100),China.
文摘Three-dimensional(3D)hydrogel models play a crucial role in tissue engineering for promoting tissue regeneration.A biomimetic microchannel network system in the 3D hydrogel model is necessary for optimal cellular function.This report describes the preparation of a biomimetic hydrogel scaffold with an internal microchannel network,using electrospinning techniques and the sacrificial template method for 3D cell culture.Microchannels and cavities were created within the gelatin methacryloyl(GelMA)hydrogel by sacrificing polyvinyl alcohol(PVA)electrospun fibers(>10µm),resulting in the creation of microvessel-like channels.Mechanical characterizations,swelling properties,and biodegradation analysis were conducted to investigate the feasibility of a biomimetic microchannel network hydrogel scaffold for 3D cell culture applications.Compared to pure GelMA hydrogel,the hydrogel with microchannels promoted cell proliferation,adhesion,and endothelial tube formation.Moreover,the results confirmed that the biomimetic microchannel network scaffold had a major impact on the distribution and arrangement of human umbilical vein endothelial cells(HUVECs)and can enable the formation of artificial microvasculature by the culture of HUVECs and cell media perfusion.
基金YSZ received funding from National Institutes of Health(K99CA201603,R00CA201603,R21EB025270,R21EB026175,R01EB028143,R03EB027984)National Science Foundation(1935105)+1 种基金Brigham Research Institute New England Anti-Vivisection Foundation,and American Fund for Alternatives to Animal Research(AFAAR).AZ received funding from National Institutes of Health(K08DK113244,R01MD012579)SD received funding from National Institutes of Health(R01MD012579-UT20664DS).
文摘This study presents a simple and robust three-dimensional human hepatic tissue model to emulate steatotic and fibrotic conditions and provide an in vitro model for drug testing and mechanistic studies.Using a photolithographic biofabrication method with a photomask featuring hexagonal units,liver cells,including a human hepatic cell line(HepG2-C3A)and a human hepatic stellate cell line(LX-2)were embedded in gelatin methacryloyl hydrogel.Hepatic steatosis was induced by supraphysiological concentration of free fatty acids;hepatic fibrosis was induced by transforming growth factor-β1.Induction of steatosis was confirmed by Oil Red O and BODIPY staining and was inhibited with toyocamycin and obeticholic acid.Induction of fibrosis was confirmed by immunostaining for collagen type I and alpha smooth muscle actin and inhibited by rapamycin and curcumin treatment.This model was further preliminarily validated using primary human hepatocytes in a similar setup.These constructs provide a viable,biologically relevant,and higher throughput model of hepatic steatosis and fibrosis and may facilitate the study of the mechanisms of disease and testing of liver-directed drugs.
文摘New water soluble and photocrosslinkable prepolymers containing acrylate and quaternary ammonium salt groups were synthesized from epoxy phenolic resin via ring-opening reaction with acrylic acid and with aqueous solution of triethylamine hydrochloride successively. The second reaction needs no phase transfer catalyst to accelerate, since the product formed can act as a phase transfer catalyst. The prepolymer obtained contains both photocrosslinkable acrylate groups and hydrophilic quaternary ammonium salt groups. Optimum conditions for these reactions were studied. The photosensitivity of the prepolymer was also investigated. The effects of different photoinitiators, different crosslinkable diluent monomers and amine accelerator on the photosensitivity of the prepolymer were compared. The photoinitiator of hydrogen abstraction type is still effective without using amine or alcohol as accelerator, because the prepolymer contains a H beside the OH groups formed in the ring-opening reactions.
基金supported by the National Natural Science Foundation of China(22077092)the Training Program of the Major Research Plan of the National Natural Science Foundation of China(91959123)+1 种基金the Open Project Program of the State Key Laboratory of Radiation Medicine and Protection(GZK1202132,GZK1202017,GZK1202140)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Controlled drug delivery holds great potential for effective tumor treatment owing to the merits of overcoming drug resistance and improving therapeutic efficacy while minimizing systemic toxicity.However,accurate and controllable delivery of chemotherapeutics into tumor tissue with high efficiency remains a huge challenge.Taking advantage of the UV-emitting characteristics of upconversion nanoparticles(UCNPs),herein we for the first time report an MMP-2 enzyme and near infrared(NIR)dual-mediated sequential drug delivery and in-situ immobilization(ENDDI)system that is fabricated by decorating UCNPs with MMP-2 responsive and photocrosslinkable peptide bearing anticancer drug doxorubicin(DOX)for overcoming multidrug resistance.Upon cleavage with tumor-specific MMP-2,the peptide fragment containing a photolabile benzophenone(BP)and DOX could be released and in-situ immobilized within the tumor through the covalent crosslinking reaction between BP and neighboring biomolecules under the excitation of converted UVemission from UCNPs,which remarkably blocks the exocytosis of DOX leading to prolonged drug retention,achieving significant suppression of DOX-resistant breast tumors.Our current dual stimuli-mediated sequential drug delivery and in-situ immobilization represent a generalizable strategy for the effective treatment of multidrug resistant tumors.
基金supported by the National Natural Science Foundation of China(No.20704040)
文摘Photoinitiated crosslinking of ethylene-propylene-diene terpolymer （EPDM） blends filled with calcium carbonate, talc and calcined kaolin （CK） in the presence of benzil dimethyl ketal as photoinitiator and trimethylolpropane triacrylate as crosslinker and their related properties have been studied by different analytical methods, The results from gel content and heat extension determination show that the efficiency ofphotocrosslinking of EPDM increases with increasing the content of diene and its molecular weight. The EPDM blends with 100 phr different inorganic fillers can be photocrosslinked to gel content of above 60% by 5 s UV-irradiation under optimum conditions. Under the same conditions of irradiation, the orders of photocrosslinking rate and final gel content are EPDM/CaCO3 〉 EPDM/talc 〉 EPDM/CK. The data from thermogravimetric analysis, dynamic mechanical thermal analysis, electrical properties, mechanical tests and scanning electron microscopy show that UV irradiation crosslinking apparently enhances the thermal stability, mechanical properties and electrical properties of the photocrosslinked EPDM/inorganic filler samples. Although the attenuated total-reflection FTIR data show that inorganic fillers can promote the surface photo-oxidation of EPDM/inorganic filler samples with increasing the irradiation time, the above related properties of the photocrosslinked EPDM blends irradiated within 5 s are enough to satisfy many applications in the cable industry.
