The implantation of synthetic polymeric scaffolds induced foreign-body reaction(FBR)seriously influence the wound healing and impair functionality recovery.A novel short peptide,mechano-growth factor(MGF),was introduc...The implantation of synthetic polymeric scaffolds induced foreign-body reaction(FBR)seriously influence the wound healing and impair functionality recovery.A novel short peptide,mechano-growth factor(MGF),was introduced in this study to modify an electrospun polycaprolactone(PCL)fibrous scaffold to direct the macrophage phenotype transition and mitigate the FBR.In vitro studies discovered the cell signal transduction mechanism of MGF regulates the macrophage polarization via the expression of related genes and proteins.We found that macrophages response the MGF stimuli via endocytosis,then MGF promotes the histone acetylation and upregulates the STAT6 expression to direct an anti-inflammatory phenotype transition.Subsequently,an immunoregulatory electrospun PCL fibrous scaffold was modified by silk fibroin(SF)single-component layer-by-layer assembly,and the SF was decorated with MGF via click chemistry.Macrophages seeded on scaffold to identify the function of MGF modified scaffold in directing macrophage polarization in vitro.Parallelly,rat subcutaneous implantation model and rat tendon adhesion model were performed to detect the immunomodulatory ability of the MGF-modified scaffold in vivo.The results demonstrate that MGF-modified scaffold is beneficial to the transformation of macrophages to M2 phenotype in vitro.More importantly,MGF-functionalized scaffold can inhibit the FBR at the subcutaneous tissue and prevent tissue adhesion.展开更多
The cell membranes,derived from natural sources,possesses unique physicochemical properties of phospholipid bilayers and biological functionalities of membrane proteins.This makes it an ideal biomimetic coating to enh...The cell membranes,derived from natural sources,possesses unique physicochemical properties of phospholipid bilayers and biological functionalities of membrane proteins.This makes it an ideal biomimetic coating to enhance the in vivo circulation and retention time of micro/nanodrug carriers,provide targeted drug delivery effects,and neutralize bacterial toxins.Notably,recent studies have successfully coated various types of cell membranes onto the surfaces of macroscopic materials,such as electrospun fiber scaffolds and decellularized matrices,to promote tissue repair,modulate host responses to foreign materials,and alleviate inflammation.This review comprehensively summarizes the latest research progress in the modification of macroscopic biomaterials with cell membranes.The insights provided aim to serve as a valuable reference for the preparation of cell membrane biomimetic coatings and their applications in the field of tissue repair.展开更多
The Ru complexes have garnered a great deal of attention for antitumor phototherapy;however, achieving efficient cellular uptake and tumor-specific activation represents a major challenge. Herein, we synthesize a hypo...The Ru complexes have garnered a great deal of attention for antitumor phototherapy;however, achieving efficient cellular uptake and tumor-specific activation represents a major challenge. Herein, we synthesize a hypoxia-activated Ru complex(Ru ANM) and construct it into supramolecular polymers(Poly Ru ANM) through high binding affinity interaction. The amphiphilic supramolecular polymers possess self-assembly, resulting in the formation of diverse nanostructures exhibiting a range of morphologies by simply adjusting the host-guest ratio. As the polymer nanostructure size and morphology have been optimized, Poly Ru ANM prevents premature drug leakage and accumulates rapidly in the tumor cells. In the tumor hypoxia microenvironment, the polymer undergoes selective activation and disintegration, leading to the unlock of Ru complexes.Notably, the subsequent application of red light irradiation exacerbates the hypoxia and potentiates the liberation of the Ru complexes. This polymer design concept provides some novel insights into on-demand drug delivery and smart chemophotodynamic therapy.展开更多
Proton exchange membrane fuel cells(PEMFCs)are promising power sources owing to their high-power/energy densities and low pollution emissions.With the increasing demand for electricity for various low-power devices,sm...Proton exchange membrane fuel cells(PEMFCs)are promising power sources owing to their high-power/energy densities and low pollution emissions.With the increasing demand for electricity for various low-power devices,small-scale storage of electricity encountered bottle-neck,which provides new opportunities for PEMFC.Owing to the high specific energy of PEMFCs,the utilization of this technology for small-scale applications has recently attracted significant attention.In recent years,considerable effort has been made to advance PEMFC technology and applications,especially in the small-scale PEMFC commercial market.The current review provides a holistic overview of the cutting-edge developments of small-scale PEMFCs in the transportation,stationary,and portable power generator fields.In particular,we examine current literature on the development of small-scale PEMFCs and discuss the operating complexity of PEMFC systems for different applications.Finally,we provide a forwardlooking perspective on the strategies for small-scale high-specific-power PEMFC systems.展开更多
The development of small-diameter vascular grafts that can meet the long-term patency required for implementation in clinical practice presents a key challenge to the research field.Although techniques such as the bra...The development of small-diameter vascular grafts that can meet the long-term patency required for implementation in clinical practice presents a key challenge to the research field.Although techniques such as the braiding of scaffolds can offer a tunable platform for fabricating vascular grafts,the effects of braided silk fiber skeletons on the porosity,remodeling,and patency in vivo have not been thoroughly investigated.展开更多
Proton exchange membrane(PEM)fuel cell has been regarded as a promising approach to the decarbonization and diversification of energy sources.In recent years,durability and cost issues of PEM fuel cells are increasing...Proton exchange membrane(PEM)fuel cell has been regarded as a promising approach to the decarbonization and diversification of energy sources.In recent years,durability and cost issues of PEM fuel cells are increasingly significant with the rapid increase of power density.However,the failure to maintain the cell consistency,as one major cause of the above issue,has attracted little attention.Therefore,this study intends to figure out the underlying cause of cell inconsistency and provide solutions to it from the perspective of multi-physics transport coupled with electrochemical reactions.The PEM fuel cells with electrodes under two compression modes are firstly discussed to fully explain the relationship of cell performance and consistency to electrode structure and multi-physics transport.The result indicates that one main cause of cell inconsistency is the intrinsic conflict between the separated transport and cooperated consumption of oxygen and electron throughout the active area.Then,a mixed-pathway electrode design is proposed to reduce the cell inconsistency by enhancing the mixed transport of oxygen and electron in the electrode.It is found that the mixing of pathways in electrodes at under-rib region is more effective than that at the under-channel region,and can achieve an up to 40%reduction of the cell inconsistency with little(3.3%)sacrificed performance.In addition,all the investigations are implemented based on a self-developed digitalization platform that reconstructs the complex physical–chemical system of PEM fuel cells.The fully observable physical information of the digitalized cells provides strong support to the related analysis.展开更多
The O_(2) permeation barrier across the nanoscale ionomer films on electrocatalysts contributes to a major performance loss of proton exchange membrane(PEM)fuel cells under low Pt loading.Enhancing O_(2) transport thr...The O_(2) permeation barrier across the nanoscale ionomer films on electrocatalysts contributes to a major performance loss of proton exchange membrane(PEM)fuel cells under low Pt loading.Enhancing O_(2) transport through the ionomer films is essential for developing low Pt loading catalyst materials in high-performance PEM fuel cells.This study found that adding an ionic liquid(IL)can effectively mitigate the dense ionomer ultrathin sublayer formed on the Pt surface,which severely hinders O_(2) transport to the catalyst sites.The molecular dynamics simulation results show that adding the IL significantly alters the ionomer ultrathin sublayer structure by inhibiting its tight arrangement of perfluorosulfonic acid chains but scarcely impacts the ultrathin sublayer thickness.Additionally,the IL addition provides a larger free space for O_(2) dissolution in the ultrathin sublayer.Consequently,due to IL molecules’presence,the O_(2) density in the ultrathin sublayer on the Pt surface is improved by an order of magnitude,which will benefit the catalytic efficiency,and the O_(2) permeation flux across the ionomer film is increased by up to 8 times,which will reduce the O_(2) transport loss of the catalyst layer.展开更多
Orthodontic forces can cause stress and strain concentration and microcracks on tooth root surfaces.This study aimed to analyze whether a lingual orthodontic appliance was more likely to cause root stress concentratio...Orthodontic forces can cause stress and strain concentration and microcracks on tooth root surfaces.This study aimed to analyze whether a lingual orthodontic appliance was more likely to cause root stress concentration and root resorption than the traditional buccal appliance.A finite element model of the root of the maxillary central incisor with straight,buccal,and lingual curvatures was established.A load perpendicular to the tooth surface on the buccal and lingual surfaces of the central incisor was applied,and the stress and strain concentration at the root apex was compared.The stress and strain at the root apex of the lingual cingulum group were lesser than those of the buccal group;little difference was observed between the lingual and buccal clinical crown central augmentation groups.The stress and strain at the root apex of the lingual direction movement group were greater than those of the buccal direction movement group.The direction of the root curvature also influenced the amount of stress and strain at the root apex.The difference in the risk of root resorption between lingual and buccal orthodontics is dependent on the height of the bracket placement.The loading direction of the orthodontic force and direction of the root curvature also affect the stress and strain at the root apex.展开更多
基金We acknowledge the funding support from the National Natural Science Foundation of China(31971258,11532004)the 111 Project(B06023,B13003)Chongqing Postdoctoral Science Foundation(csts2019jcyj-bsh0068).
文摘The implantation of synthetic polymeric scaffolds induced foreign-body reaction(FBR)seriously influence the wound healing and impair functionality recovery.A novel short peptide,mechano-growth factor(MGF),was introduced in this study to modify an electrospun polycaprolactone(PCL)fibrous scaffold to direct the macrophage phenotype transition and mitigate the FBR.In vitro studies discovered the cell signal transduction mechanism of MGF regulates the macrophage polarization via the expression of related genes and proteins.We found that macrophages response the MGF stimuli via endocytosis,then MGF promotes the histone acetylation and upregulates the STAT6 expression to direct an anti-inflammatory phenotype transition.Subsequently,an immunoregulatory electrospun PCL fibrous scaffold was modified by silk fibroin(SF)single-component layer-by-layer assembly,and the SF was decorated with MGF via click chemistry.Macrophages seeded on scaffold to identify the function of MGF modified scaffold in directing macrophage polarization in vitro.Parallelly,rat subcutaneous implantation model and rat tendon adhesion model were performed to detect the immunomodulatory ability of the MGF-modified scaffold in vivo.The results demonstrate that MGF-modified scaffold is beneficial to the transformation of macrophages to M2 phenotype in vitro.More importantly,MGF-functionalized scaffold can inhibit the FBR at the subcutaneous tissue and prevent tissue adhesion.
基金National Natural Science Foundation of China(grant number 31971258,32371405).
文摘The cell membranes,derived from natural sources,possesses unique physicochemical properties of phospholipid bilayers and biological functionalities of membrane proteins.This makes it an ideal biomimetic coating to enhance the in vivo circulation and retention time of micro/nanodrug carriers,provide targeted drug delivery effects,and neutralize bacterial toxins.Notably,recent studies have successfully coated various types of cell membranes onto the surfaces of macroscopic materials,such as electrospun fiber scaffolds and decellularized matrices,to promote tissue repair,modulate host responses to foreign materials,and alleviate inflammation.This review comprehensively summarizes the latest research progress in the modification of macroscopic biomaterials with cell membranes.The insights provided aim to serve as a valuable reference for the preparation of cell membrane biomimetic coatings and their applications in the field of tissue repair.
基金supported by the National Natural Science Foundation of China (22078046)the Fundamental Research Fundamental Funds for the Central Universities (DUT22LAB601)+2 种基金the Liaoning Binhai Laboratory (LB-2023-03)the China Postdoctoral Science Foundation (2023M740487)the Postdoctoral Fellowship Program of CPSF (GZC20230353)。
文摘The Ru complexes have garnered a great deal of attention for antitumor phototherapy;however, achieving efficient cellular uptake and tumor-specific activation represents a major challenge. Herein, we synthesize a hypoxia-activated Ru complex(Ru ANM) and construct it into supramolecular polymers(Poly Ru ANM) through high binding affinity interaction. The amphiphilic supramolecular polymers possess self-assembly, resulting in the formation of diverse nanostructures exhibiting a range of morphologies by simply adjusting the host-guest ratio. As the polymer nanostructure size and morphology have been optimized, Poly Ru ANM prevents premature drug leakage and accumulates rapidly in the tumor cells. In the tumor hypoxia microenvironment, the polymer undergoes selective activation and disintegration, leading to the unlock of Ru complexes.Notably, the subsequent application of red light irradiation exacerbates the hypoxia and potentiates the liberation of the Ru complexes. This polymer design concept provides some novel insights into on-demand drug delivery and smart chemophotodynamic therapy.
基金This research is funded by the National Natural Science Foundation of China(No.52106105)the China Postdoctoral Science Foundation(No.2022TQ0231)the Tianjin Research Innovation Project for Postgraduate Students(No.2021YJSB127).
文摘Proton exchange membrane fuel cells(PEMFCs)are promising power sources owing to their high-power/energy densities and low pollution emissions.With the increasing demand for electricity for various low-power devices,small-scale storage of electricity encountered bottle-neck,which provides new opportunities for PEMFC.Owing to the high specific energy of PEMFCs,the utilization of this technology for small-scale applications has recently attracted significant attention.In recent years,considerable effort has been made to advance PEMFC technology and applications,especially in the small-scale PEMFC commercial market.The current review provides a holistic overview of the cutting-edge developments of small-scale PEMFCs in the transportation,stationary,and portable power generator fields.In particular,we examine current literature on the development of small-scale PEMFCs and discuss the operating complexity of PEMFC systems for different applications.Finally,we provide a forwardlooking perspective on the strategies for small-scale high-specific-power PEMFC systems.
基金The authors graciously acknowledge professor Deling Kong's lab for their assistance with the animal experiments.This project was supported by the National Natural Science Foundation of China(T2288101,32000968,32071359,11827803,and U20A20390)Beijing Natural Science Foundation(M22026)Fundamental Research Funds for the Central Universities,and 111 Project(B13003).
文摘The development of small-diameter vascular grafts that can meet the long-term patency required for implementation in clinical practice presents a key challenge to the research field.Although techniques such as the braiding of scaffolds can offer a tunable platform for fabricating vascular grafts,the effects of braided silk fiber skeletons on the porosity,remodeling,and patency in vivo have not been thoroughly investigated.
基金supported by the National Natural Science Foundation of China(52176196)the Natural Science Foundation of Tianjin(China)for Distinguished Young Scholars(18JCJQJC46700).
文摘Proton exchange membrane(PEM)fuel cell has been regarded as a promising approach to the decarbonization and diversification of energy sources.In recent years,durability and cost issues of PEM fuel cells are increasingly significant with the rapid increase of power density.However,the failure to maintain the cell consistency,as one major cause of the above issue,has attracted little attention.Therefore,this study intends to figure out the underlying cause of cell inconsistency and provide solutions to it from the perspective of multi-physics transport coupled with electrochemical reactions.The PEM fuel cells with electrodes under two compression modes are firstly discussed to fully explain the relationship of cell performance and consistency to electrode structure and multi-physics transport.The result indicates that one main cause of cell inconsistency is the intrinsic conflict between the separated transport and cooperated consumption of oxygen and electron throughout the active area.Then,a mixed-pathway electrode design is proposed to reduce the cell inconsistency by enhancing the mixed transport of oxygen and electron in the electrode.It is found that the mixing of pathways in electrodes at under-rib region is more effective than that at the under-channel region,and can achieve an up to 40%reduction of the cell inconsistency with little(3.3%)sacrificed performance.In addition,all the investigations are implemented based on a self-developed digitalization platform that reconstructs the complex physical–chemical system of PEM fuel cells.The fully observable physical information of the digitalized cells provides strong support to the related analysis.
基金This research was supported by the National Natural Science Foundation of China(Grant No.51921004)the Natural Science Foundation for Outstanding Young Scholars of Tianjin(Grant No.18JCJQJC46700).
文摘The O_(2) permeation barrier across the nanoscale ionomer films on electrocatalysts contributes to a major performance loss of proton exchange membrane(PEM)fuel cells under low Pt loading.Enhancing O_(2) transport through the ionomer films is essential for developing low Pt loading catalyst materials in high-performance PEM fuel cells.This study found that adding an ionic liquid(IL)can effectively mitigate the dense ionomer ultrathin sublayer formed on the Pt surface,which severely hinders O_(2) transport to the catalyst sites.The molecular dynamics simulation results show that adding the IL significantly alters the ionomer ultrathin sublayer structure by inhibiting its tight arrangement of perfluorosulfonic acid chains but scarcely impacts the ultrathin sublayer thickness.Additionally,the IL addition provides a larger free space for O_(2) dissolution in the ultrathin sublayer.Consequently,due to IL molecules’presence,the O_(2) density in the ultrathin sublayer on the Pt surface is improved by an order of magnitude,which will benefit the catalytic efficiency,and the O_(2) permeation flux across the ionomer film is increased by up to 8 times,which will reduce the O_(2) transport loss of the catalyst layer.
基金This work was supported by the National Natural Science Foundation of China(No.U20A20390 and 11827803).
文摘Orthodontic forces can cause stress and strain concentration and microcracks on tooth root surfaces.This study aimed to analyze whether a lingual orthodontic appliance was more likely to cause root stress concentration and root resorption than the traditional buccal appliance.A finite element model of the root of the maxillary central incisor with straight,buccal,and lingual curvatures was established.A load perpendicular to the tooth surface on the buccal and lingual surfaces of the central incisor was applied,and the stress and strain concentration at the root apex was compared.The stress and strain at the root apex of the lingual cingulum group were lesser than those of the buccal group;little difference was observed between the lingual and buccal clinical crown central augmentation groups.The stress and strain at the root apex of the lingual direction movement group were greater than those of the buccal direction movement group.The direction of the root curvature also influenced the amount of stress and strain at the root apex.The difference in the risk of root resorption between lingual and buccal orthodontics is dependent on the height of the bracket placement.The loading direction of the orthodontic force and direction of the root curvature also affect the stress and strain at the root apex.
