Ameloblasts are specialized cells derived from the dental epithelium that produce enamel,a hierarchically structured tissue comprised of highly elongated hydroxylapatite(OHAp)crystallites.The unique function of the ep...Ameloblasts are specialized cells derived from the dental epithelium that produce enamel,a hierarchically structured tissue comprised of highly elongated hydroxylapatite(OHAp)crystallites.The unique function of the epithelial cells synthesizing crystallites and assembling them in a mechanically robust structure is not fully elucidated yet,partly due to limitations with in vitro experimental models.Herein,we demonstrate the ability to generate mineralizing dental epithelial organoids(DEOs)from adult dental epithelial stem cells(aDESCs)isolated from mouse incisor tissues.DEOs expressed ameloblast markers,could be maintained for more than five months(11 passages)in vitro in media containing modulators of Wnt,Egf,Bmp,Fgf and Notch signaling pathways,and were amenable to cryostorage.When transplanted underneath murine kidney capsules,organoids produced OHAp crystallites similar in composition,size,and shape to mineralized dental tissues,including some enamel-like elongated crystals.DEOs are thus a powerful in vitro model to study mineralization process by dental epithelium,which can pave the way to understanding amelogenesis and developing regenerative therapy of enamel.展开更多
The development of highly efficient and stable Pd-based catalysts is crucial to improve their sluggish oxygen reduction reaction(ORR)kinetics in acid media.To improve ORR activity and utilization efficiency of Pd,an i...The development of highly efficient and stable Pd-based catalysts is crucial to improve their sluggish oxygen reduction reaction(ORR)kinetics in acid media.To improve ORR activity and utilization efficiency of Pd,an ideal catalyst should have ORR-favorable chemical environment,optimized geometric structure,and long periods of operation.In this work,we first synthesize a novel trimetallic Au@PdPb core–shell catalyst consisting of PdPb alloy nano-layers grown on the surface of ultrathin Au nanowires(NWs)by a two-step water-bath method.The Au@PdPb NWs have the merits of anisotropic one-dimensional nanostructure,high utilization efficiency of Pd atoms and doping of Pb atoms.Because of the structural and multiple compositional advantages,Au@PdPb NWs exhibit remarkably enhanced ORR activity with a high haIf-wave potential(0.827 V),much better than those of commercial Pd black(0.788 V)and bimetallic Au@Pd NWs(0.803 V).Moreover,Au@PdPb NWs display better electrocatalytic stability for the ORR than those of Pd black and Au@Pd NWs.This study demonstrates the validity of our approach for deriving highly ORR-active Pd-based catalysts by modifying their structure and composition.展开更多
基金supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea Government (MSIP) (NRF-2022R1A2B5B03001627)facilities operated by Northwestern University:EPIC and SPID facilities of Northwestern University’s NUANCE Center,which have received support from the SHyNE Resource (NSF ECCS-2025633)+4 种基金the IIN,and Northwestern’s MRSEC program (NSF DMR-1720139)MatCI,supported by the MRSEC program (NSF DMR-1720139) at the Materials Research Centerthe Northwestern University George M.O’Brien Kidney Research Core Center (NU GoKidney),an NIH/NIDDK funded program (P30DK114857)supported in part by NIH UH3 DE028872supported in part by the National Science Foundation through a Graduate Research Fellowship (DGE-1842165)
文摘Ameloblasts are specialized cells derived from the dental epithelium that produce enamel,a hierarchically structured tissue comprised of highly elongated hydroxylapatite(OHAp)crystallites.The unique function of the epithelial cells synthesizing crystallites and assembling them in a mechanically robust structure is not fully elucidated yet,partly due to limitations with in vitro experimental models.Herein,we demonstrate the ability to generate mineralizing dental epithelial organoids(DEOs)from adult dental epithelial stem cells(aDESCs)isolated from mouse incisor tissues.DEOs expressed ameloblast markers,could be maintained for more than five months(11 passages)in vitro in media containing modulators of Wnt,Egf,Bmp,Fgf and Notch signaling pathways,and were amenable to cryostorage.When transplanted underneath murine kidney capsules,organoids produced OHAp crystallites similar in composition,size,and shape to mineralized dental tissues,including some enamel-like elongated crystals.DEOs are thus a powerful in vitro model to study mineralization process by dental epithelium,which can pave the way to understanding amelogenesis and developing regenerative therapy of enamel.
基金supported by the Academic Research Fund(AcRF)Tier 1 Grant(No.RG105/19)from the Ministry of Education in Singapore,the National Natural Science Foundation of China(No.21875112)and the China Scholarship Council(No.201906090199).
文摘The development of highly efficient and stable Pd-based catalysts is crucial to improve their sluggish oxygen reduction reaction(ORR)kinetics in acid media.To improve ORR activity and utilization efficiency of Pd,an ideal catalyst should have ORR-favorable chemical environment,optimized geometric structure,and long periods of operation.In this work,we first synthesize a novel trimetallic Au@PdPb core–shell catalyst consisting of PdPb alloy nano-layers grown on the surface of ultrathin Au nanowires(NWs)by a two-step water-bath method.The Au@PdPb NWs have the merits of anisotropic one-dimensional nanostructure,high utilization efficiency of Pd atoms and doping of Pb atoms.Because of the structural and multiple compositional advantages,Au@PdPb NWs exhibit remarkably enhanced ORR activity with a high haIf-wave potential(0.827 V),much better than those of commercial Pd black(0.788 V)and bimetallic Au@Pd NWs(0.803 V).Moreover,Au@PdPb NWs display better electrocatalytic stability for the ORR than those of Pd black and Au@Pd NWs.This study demonstrates the validity of our approach for deriving highly ORR-active Pd-based catalysts by modifying their structure and composition.
