An in situ synthesized TiC particle reinforced composite layer on Ti6Al4V were fabricated by laser induced reaction of the pre placed mixed powders of Ti and Cr 3C 2. The microstructure of the composite layer was stro...An in situ synthesized TiC particle reinforced composite layer on Ti6Al4V were fabricated by laser induced reaction of the pre placed mixed powders of Ti and Cr 3C 2. The microstructure of the composite layer was strongly related to the composition of original powders and also the laser processing parameters. Under certain processing parameters, the matrix of the composite layer was transferred from dual α + β to single phase β with increasing Cr 3C 2 content in the original powder mixture. The TiC particles were fine and uniformly dispersed in the matrix. Furthermore, the fine TiC particles show excellent compatibility with the matrix, thus offering good wear performance.展开更多
Aim To develop pluronic F127 （PF127） based formulations of penciclovir （PCV） aimed at enhancing its ocular bioavailability. Methods Thermosensitive in situ gels of penciclovir were prepared through combination of ...Aim To develop pluronic F127 （PF127） based formulations of penciclovir （PCV） aimed at enhancing its ocular bioavailability. Methods Thermosensitive in situ gels of penciclovir were prepared through combination of HPMC K4M or carbopol 934P and pluronic F127. Optimized formulations were examined through measuring gelation temperature, rheology speciality, drug release behavior, pharmacokinetics and ocular irritation. Results The gelation temperature was reduced by adding HPMC K4M or carbopol 934P, and the viscosity was enhanced slightly. Either HPMC K4M or carbopol 934P delayed the release of PCV from in situ gel. PCV was released by non-Fickian diffusion. The study of ocular irritation for different PCV formulations did not show any irritation or damage for the cornea. PCV bioavailability from combination of carbopol 934P and pluronic F127 gels was higher than that obtained from any other gels. Conclusion Pluronic F127 formulations of PCV can be used as liquid for administration by instilling into the eye. Facilitated by the appropriate eye temperature, the formulations were transformed to gel phase. On the basis of in vitro and in vivo results, PCV formulations containing HPMC K4M or carbopol 934P and low concentration of pluronic F127 （12%） showed potential for use as a drug delivery system with improved ocular bioavailability.展开更多
Irregular articular cartilage injury is a common type of joint trauma,often resulting from intense impacts and other factors that lead to irregularly shaped wounds,the limited regenerative capacity of cartilage and th...Irregular articular cartilage injury is a common type of joint trauma,often resulting from intense impacts and other factors that lead to irregularly shaped wounds,the limited regenerative capacity of cartilage and the mismatched shape of the scaffods have contributed to unsatisfactory therapeutic outcomes.While injectable materials are a traditional solution to adapt to irregular cartilage defects,they have limitations,and injectable materials often lack the porous microstructures favorable for the rapid proliferation of cartilage cells.In this study,an injectable porous polyurethane scaffold named PU-BDO-Gelatin-Foam(PUBGF)was prepared.After injection into cartilage defects,PUBGF forms in situ at the site of the defect and exhibits a dynamic microstructure during the initial two weeks.This dynamic microstructure endows the scaffold with the ability to retain substances within its interior,thereby enhancing its capacity to promote chondrogenesis.Furthermore,the chondral repair efficacy of PUBGF was validated by directly injecting it into rat articular cartilage injury sites.The injectable PUBGF scaffold demonstrates a superior potential for promoting the repair of cartilage defects when compared to traditional porous polyurethane scaffolds.The substance retention ability of this injectable porous scaffold makes it a promising option for clinical applications.展开更多
Sequencing batch reactor(SBR)for enhanced biological phosphorus removal(EBPR)processes was used to investigate the impact of the temperature shock on the competition between phosphorus-accumulating organisms(PAOs)and ...Sequencing batch reactor(SBR)for enhanced biological phosphorus removal(EBPR)processes was used to investigate the impact of the temperature shock on the competition between phosphorus-accumulating organisms(PAOs)and glycogen accumulating organisms(GAOs)in start-up stage.During the 34 days operation,SBR was set with temperature variation(0-5 d,22±1℃;6-13 d,29±1℃;14-34 d,14±1℃).PAOs and GAOs were analyzed by fluorescent in situ hybridization(FISH),and intracellular polyphosphate granules were stained by Neisser-stain.The results showed that the influence of temperature shock on PAOs’abundance was more serious than that on GAOs in the enriching process.Under sudden and substantially temperature variation,from 22±1℃ to 29±1℃ and then to 14±1℃,the domination of PAOs was deteriorated.After temperature shock,PAOs’competitive advantages at low temperature that concluded in other study did not appear in our study.As mesophilic,GAOs(indicated by Alphaproteobacteria and Gammaproteobacteria)were more temperature adaptive and better grew and took the domination at 14±1℃ in the end.In the competition process,organisms of tetrad forming organisms(TFOs)-like shape which were considered as typical GAOs,were observed.With the evidence of poly-P granules containing by Neisser-straining and result of FISH,these organisms of TFOs-like shape were better to be assumed as adaption state or a special self-protecting shape of PAOs.展开更多
In situ-forming hydrogels are an attractive option for corneal regeneration, and the delivery of growth factorsfrom such constructs have the potential to improve re-epithelialization and stromal remodeling. However,ch...In situ-forming hydrogels are an attractive option for corneal regeneration, and the delivery of growth factorsfrom such constructs have the potential to improve re-epithelialization and stromal remodeling. However,challenges persist in controlling the release of therapeutic molecules from hydrogels. Here, an in situ-forming bioorthogonallycrosslinked hydrogel containing growth factors tethered via photocleavable linkages (PC-HAColhydrogel) was developed to accelerate corneal regeneration. Epidermal growth factor (EGF) was conjugated tothe hydrogel backbone through photo-cleavable (PC) spacer arms and was released when exposed to mild intensityultraviolet (UV) light (2–5 mW/cm2, 365 nm). The PC-HACol hydrogel rapidly gelled within a few minuteswhen applied to corneal defects, with excellent transparency and biocompatibility. After subsequentexposure to UV irradiation, the hydrogel promoted the proliferation and migration of corneal epithelial cells invitro. The rate of re-epithelialization was positively correlated to the frequency of irradiation, verified through exvivo rabbit cornea organ culture studies. In an in vivo rat corneal wound healing study, the PC-HACol hydrogelexposed to UV light significantly promoted re-epithelialization, the remodeling of stromal layers, and exhibitedsignificant anti-scarring effects, with minimal α-SMA and robust ALDH3A1 expression. Normal differentiation ofthe regenerated epithelia after healing was evaluated by expression of the corneal epithelial biomarker, CK12.The remodeled cornea exhibited full recovery of corneal thickness and layer number without hyperplasia of theepithelium.展开更多
A lack of biological activity hinders the application of synthetic hydrogels in tissue engineering and regenerative medicine.However,the use of glycopolypeptides in hydrogel synthesis may provide the materials with th...A lack of biological activity hinders the application of synthetic hydrogels in tissue engineering and regenerative medicine.However,the use of glycopolypeptides in hydrogel synthesis may provide the materials with the desired biological activities.Herein,we prepared three in situ-forming hydrogels from various phenol-functionalized glycopolypeptides.The gelation time,mechanical properties,degradation properties,and biocompatibility of the hydrogels were assessed.Gelation time ranged from 11 to 380s,depending on the concentration of horseradish peroxidase.The galactose-modified polypeptide hydrogel showed the highest storage modulus with an obvious stress relaxation phenomenon.The prepared hydrogels exhibited good degradation properties and compatibility to cells and tissues.Furthermore,the rate of immune cell accumulation around the mannosemodified polypeptide hydrogel was the fastest among the hydrogels.展开更多
文摘An in situ synthesized TiC particle reinforced composite layer on Ti6Al4V were fabricated by laser induced reaction of the pre placed mixed powders of Ti and Cr 3C 2. The microstructure of the composite layer was strongly related to the composition of original powders and also the laser processing parameters. Under certain processing parameters, the matrix of the composite layer was transferred from dual α + β to single phase β with increasing Cr 3C 2 content in the original powder mixture. The TiC particles were fine and uniformly dispersed in the matrix. Furthermore, the fine TiC particles show excellent compatibility with the matrix, thus offering good wear performance.
文摘Aim To develop pluronic F127 （PF127） based formulations of penciclovir （PCV） aimed at enhancing its ocular bioavailability. Methods Thermosensitive in situ gels of penciclovir were prepared through combination of HPMC K4M or carbopol 934P and pluronic F127. Optimized formulations were examined through measuring gelation temperature, rheology speciality, drug release behavior, pharmacokinetics and ocular irritation. Results The gelation temperature was reduced by adding HPMC K4M or carbopol 934P, and the viscosity was enhanced slightly. Either HPMC K4M or carbopol 934P delayed the release of PCV from in situ gel. PCV was released by non-Fickian diffusion. The study of ocular irritation for different PCV formulations did not show any irritation or damage for the cornea. PCV bioavailability from combination of carbopol 934P and pluronic F127 gels was higher than that obtained from any other gels. Conclusion Pluronic F127 formulations of PCV can be used as liquid for administration by instilling into the eye. Facilitated by the appropriate eye temperature, the formulations were transformed to gel phase. On the basis of in vitro and in vivo results, PCV formulations containing HPMC K4M or carbopol 934P and low concentration of pluronic F127 （12%） showed potential for use as a drug delivery system with improved ocular bioavailability.
基金supported by the National Natural Science Foundation of China(Nos.52273119,51973018 and 81571410)the Beijing Science and Technology Project(Z191100002019017).
文摘Irregular articular cartilage injury is a common type of joint trauma,often resulting from intense impacts and other factors that lead to irregularly shaped wounds,the limited regenerative capacity of cartilage and the mismatched shape of the scaffods have contributed to unsatisfactory therapeutic outcomes.While injectable materials are a traditional solution to adapt to irregular cartilage defects,they have limitations,and injectable materials often lack the porous microstructures favorable for the rapid proliferation of cartilage cells.In this study,an injectable porous polyurethane scaffold named PU-BDO-Gelatin-Foam(PUBGF)was prepared.After injection into cartilage defects,PUBGF forms in situ at the site of the defect and exhibits a dynamic microstructure during the initial two weeks.This dynamic microstructure endows the scaffold with the ability to retain substances within its interior,thereby enhancing its capacity to promote chondrogenesis.Furthermore,the chondral repair efficacy of PUBGF was validated by directly injecting it into rat articular cartilage injury sites.The injectable PUBGF scaffold demonstrates a superior potential for promoting the repair of cartilage defects when compared to traditional porous polyurethane scaffolds.The substance retention ability of this injectable porous scaffold makes it a promising option for clinical applications.
基金This research was supported by the National Nature Science Foundation of China(Grant No.50821002,National Creative Research Groups)Mega-Projects of Science Research for Water(No.2008ZX07207-005-003)the National Natural Science Foundation of China(Grant No.50638020).
文摘Sequencing batch reactor(SBR)for enhanced biological phosphorus removal(EBPR)processes was used to investigate the impact of the temperature shock on the competition between phosphorus-accumulating organisms(PAOs)and glycogen accumulating organisms(GAOs)in start-up stage.During the 34 days operation,SBR was set with temperature variation(0-5 d,22±1℃;6-13 d,29±1℃;14-34 d,14±1℃).PAOs and GAOs were analyzed by fluorescent in situ hybridization(FISH),and intracellular polyphosphate granules were stained by Neisser-stain.The results showed that the influence of temperature shock on PAOs’abundance was more serious than that on GAOs in the enriching process.Under sudden and substantially temperature variation,from 22±1℃ to 29±1℃ and then to 14±1℃,the domination of PAOs was deteriorated.After temperature shock,PAOs’competitive advantages at low temperature that concluded in other study did not appear in our study.As mesophilic,GAOs(indicated by Alphaproteobacteria and Gammaproteobacteria)were more temperature adaptive and better grew and took the domination at 14±1℃ in the end.In the competition process,organisms of tetrad forming organisms(TFOs)-like shape which were considered as typical GAOs,were observed.With the evidence of poly-P granules containing by Neisser-straining and result of FISH,these organisms of TFOs-like shape were better to be assumed as adaption state or a special self-protecting shape of PAOs.
基金supported by a departmental core grant fromResearch to Prevent Blindness (RPB) as well as funding from the NationalEye Institute (NIH R01 EY035697, R01 EY033363-03,K99EY034168, and P30 EY026877)Harrington Discovery InstituteScholar-Innovator Program, and the Basic Science Research Programthrough the National Research Foundation of Korea (NRF) funded by theMinistry of Education (RS-2023-00247051)Experiments were alsoperformed in the Stanford Nano Shared Facilities and the StanfordSchool of Engineering Soft Materials Facility.
文摘In situ-forming hydrogels are an attractive option for corneal regeneration, and the delivery of growth factorsfrom such constructs have the potential to improve re-epithelialization and stromal remodeling. However,challenges persist in controlling the release of therapeutic molecules from hydrogels. Here, an in situ-forming bioorthogonallycrosslinked hydrogel containing growth factors tethered via photocleavable linkages (PC-HAColhydrogel) was developed to accelerate corneal regeneration. Epidermal growth factor (EGF) was conjugated tothe hydrogel backbone through photo-cleavable (PC) spacer arms and was released when exposed to mild intensityultraviolet (UV) light (2–5 mW/cm2, 365 nm). The PC-HACol hydrogel rapidly gelled within a few minuteswhen applied to corneal defects, with excellent transparency and biocompatibility. After subsequentexposure to UV irradiation, the hydrogel promoted the proliferation and migration of corneal epithelial cells invitro. The rate of re-epithelialization was positively correlated to the frequency of irradiation, verified through exvivo rabbit cornea organ culture studies. In an in vivo rat corneal wound healing study, the PC-HACol hydrogelexposed to UV light significantly promoted re-epithelialization, the remodeling of stromal layers, and exhibitedsignificant anti-scarring effects, with minimal α-SMA and robust ALDH3A1 expression. Normal differentiation ofthe regenerated epithelia after healing was evaluated by expression of the corneal epithelial biomarker, CK12.The remodeled cornea exhibited full recovery of corneal thickness and layer number without hyperplasia of theepithelium.
基金supported by the National Natural Science Foundation of China(Grant Nos.2157412751622307+3 种基金5152010500451833010 and51773199)the Youth Innovation Promotion AssociationCAS。
文摘A lack of biological activity hinders the application of synthetic hydrogels in tissue engineering and regenerative medicine.However,the use of glycopolypeptides in hydrogel synthesis may provide the materials with the desired biological activities.Herein,we prepared three in situ-forming hydrogels from various phenol-functionalized glycopolypeptides.The gelation time,mechanical properties,degradation properties,and biocompatibility of the hydrogels were assessed.Gelation time ranged from 11 to 380s,depending on the concentration of horseradish peroxidase.The galactose-modified polypeptide hydrogel showed the highest storage modulus with an obvious stress relaxation phenomenon.The prepared hydrogels exhibited good degradation properties and compatibility to cells and tissues.Furthermore,the rate of immune cell accumulation around the mannosemodified polypeptide hydrogel was the fastest among the hydrogels.
