Physiological repair of large-sized bone defects is great challenging in clinic due to a lack of ideal grafts suitable for bone regeneration.Decalcified bone matrix(DBM)is considered as an ideal bone regeneration scaf...Physiological repair of large-sized bone defects is great challenging in clinic due to a lack of ideal grafts suitable for bone regeneration.Decalcified bone matrix(DBM)is considered as an ideal bone regeneration scaffold,but low cell seeding efficiency and a poor osteoinductive microenvironment greatly restrict its application in large-sized bone regeneration.To address these problems,we proposed a novel strategy of bone regeneration units(BRUs)based on microgels produced by photo-crosslinkable and microfluidic techniques,containing both the osteogenic ingredient DBM and vascular endothelial growth factor(VEGF)for accurate biomimic of an osteoinductive microenvironment.The physicochemical properties of microgels could be precisely controlled and the microgels effectively promoted adhesion,proliferation,and osteogenic differentiation of bone marrow mesenchymal stem cells(BMSCs)in vitro.BRUs were successfully constructed by seeding BMSCs onto microgels,which achieved reliable bone regeneration in vivo.Finally,by integrating the advantages of BRUs in bone regeneration and the advantages of DBM scaffolds in 3D morphology and mechanical strength,a BRU-loaded DBM framework successfully regenerated bone tissue with the desired 3D morphology and effectively repaired a large-sized bone defect of rabbit tibia.The current study developed an ideal bone biomimetic microcarrier and provided a novel strategy for bone regeneration and large-sized bone defect repair.展开更多
The development of high-efficiency electrocatalysts for oxygen evolution reactions （OERs） plays an important role in the water-splitting process. Herein, we report a facile way to obtain two-dimensional （2D） singl...The development of high-efficiency electrocatalysts for oxygen evolution reactions （OERs） plays an important role in the water-splitting process. Herein, we report a facile way to obtain two-dimensional （2D） single-unit-cell-thick layered double hydroxide （LDH） nanosheets （NSs, - 1.3 nm） within only 5 min. These nanosheets presented significantly enhanced OER performance compared to bulk LDH systems fabricated using the conventional co-precipitation method. The current strategy further allowed control over the chemical compositions and electrochemical activities of the LDH NSs. For example, CoFe-LDH NSs presented the lowest overpotential of 0.28 V at 10 mA/cm2, and the NiFe-LDHs NSs showed Tafel slopes of 33.4 mV/decade and nearly 100% faradaic efficiency, thus outperforming state-of-the-art IrO2 water electrolysis catalysts. Moreover, positron annihilation lifetime spectroscopy and high-resolution transmission electron microscopy observations confirmed that rich defects and distorted lattices occurred within the 2D LDH NSs, which could supply abundant electrochemically active OER sites. Periodic calculations based on density functional theory （DFT） further showed that the CoFe- and NiFe-LDHs presented very low energy gaps and obvious spin-polarization behavior, which facilitated high electron mobility during the OER process. Therefore, this work presents a combined experimental and theoretical study on 2D single-unit-cell-thick LDH NSs with high OER activities, which have potential application in water splitting for renewable energy.展开更多
Several planar conjugated polymers and model compounds containing pyrene units are synthesized.The pre-cursor polymers and model compounds are obtained through the Pd(0)-catalyzed Suzuki reaction,then the planar struc...Several planar conjugated polymers and model compounds containing pyrene units are synthesized.The pre-cursor polymers and model compounds are obtained through the Pd(0)-catalyzed Suzuki reaction,then the planar structure is formed through intramolecular cyclization in the presence of acid.We investigate the regioisomers in intramolecular cyclization reaction by using model compounds,suggesting that the syn-and anti-structures are formed in ladder-type polymer LP1,and the syn-structure is more easily formed in LP3.The planar conjugated polymers and model compounds show untypical features of ladder-type polymers,they display broad absorption and blue or blue-green emission in solution,and interchainπ-πstacking in film still occurs.Moreover,the new polymers and model compounds are characterized by nuclear magnetic resonance(NMR)spectroscopy,gel-permeation chromatography(GPC)and cyclic voltammetry(CV).展开更多
基金financially supported by the National Key Research and Development Program of China(2017YFC1103900)the National Natural Science Foundation of China(81871502,81701843,and 81671837)+3 种基金the Shanghai Excellent Technical Leader(18XD1421500)the Program of Shanghai Academic/Technology Research Leader(19XD1431100)the Shanghai Collaborative Innovation Program on Regenerative Medicine and Stem Cell Research(2019CXJQ01)the Clinical Research Plan of SHDC(No.SHDC2020CR2045B).
文摘Physiological repair of large-sized bone defects is great challenging in clinic due to a lack of ideal grafts suitable for bone regeneration.Decalcified bone matrix(DBM)is considered as an ideal bone regeneration scaffold,but low cell seeding efficiency and a poor osteoinductive microenvironment greatly restrict its application in large-sized bone regeneration.To address these problems,we proposed a novel strategy of bone regeneration units(BRUs)based on microgels produced by photo-crosslinkable and microfluidic techniques,containing both the osteogenic ingredient DBM and vascular endothelial growth factor(VEGF)for accurate biomimic of an osteoinductive microenvironment.The physicochemical properties of microgels could be precisely controlled and the microgels effectively promoted adhesion,proliferation,and osteogenic differentiation of bone marrow mesenchymal stem cells(BMSCs)in vitro.BRUs were successfully constructed by seeding BMSCs onto microgels,which achieved reliable bone regeneration in vivo.Finally,by integrating the advantages of BRUs in bone regeneration and the advantages of DBM scaffolds in 3D morphology and mechanical strength,a BRU-loaded DBM framework successfully regenerated bone tissue with the desired 3D morphology and effectively repaired a large-sized bone defect of rabbit tibia.The current study developed an ideal bone biomimetic microcarrier and provided a novel strategy for bone regeneration and large-sized bone defect repair.
基金This work was supported by the National Basic Research Program of China （No. 2014CB932103）, the National Natural Science Foundation of China （Nos. 21301016 and 21473013）, and the Beijing Municipal Natural Science Foundation （No. 2152016）.
文摘The development of high-efficiency electrocatalysts for oxygen evolution reactions （OERs） plays an important role in the water-splitting process. Herein, we report a facile way to obtain two-dimensional （2D） single-unit-cell-thick layered double hydroxide （LDH） nanosheets （NSs, - 1.3 nm） within only 5 min. These nanosheets presented significantly enhanced OER performance compared to bulk LDH systems fabricated using the conventional co-precipitation method. The current strategy further allowed control over the chemical compositions and electrochemical activities of the LDH NSs. For example, CoFe-LDH NSs presented the lowest overpotential of 0.28 V at 10 mA/cm2, and the NiFe-LDHs NSs showed Tafel slopes of 33.4 mV/decade and nearly 100% faradaic efficiency, thus outperforming state-of-the-art IrO2 water electrolysis catalysts. Moreover, positron annihilation lifetime spectroscopy and high-resolution transmission electron microscopy observations confirmed that rich defects and distorted lattices occurred within the 2D LDH NSs, which could supply abundant electrochemically active OER sites. Periodic calculations based on density functional theory （DFT） further showed that the CoFe- and NiFe-LDHs presented very low energy gaps and obvious spin-polarization behavior, which facilitated high electron mobility during the OER process. Therefore, this work presents a combined experimental and theoretical study on 2D single-unit-cell-thick LDH NSs with high OER activities, which have potential application in water splitting for renewable energy.
基金supported by the National Natural Science Foundation of China(Nos.21274037 and 21474026)Hebei Province for Distinguished Young Scholar(No.B2012201031)+2 种基金Natural Science Foundation of Hebei Province of China(No.B2013201174)the Program for New Century Excellent Talents in University(No.NCET-12-0684)Training Program for Innovative Research Team and Leading Talent in Hebei Province University(No.LJRC024).
文摘Several planar conjugated polymers and model compounds containing pyrene units are synthesized.The pre-cursor polymers and model compounds are obtained through the Pd(0)-catalyzed Suzuki reaction,then the planar structure is formed through intramolecular cyclization in the presence of acid.We investigate the regioisomers in intramolecular cyclization reaction by using model compounds,suggesting that the syn-and anti-structures are formed in ladder-type polymer LP1,and the syn-structure is more easily formed in LP3.The planar conjugated polymers and model compounds show untypical features of ladder-type polymers,they display broad absorption and blue or blue-green emission in solution,and interchainπ-πstacking in film still occurs.Moreover,the new polymers and model compounds are characterized by nuclear magnetic resonance(NMR)spectroscopy,gel-permeation chromatography(GPC)and cyclic voltammetry(CV).
