Photosynthesis with the chloroplast works efficiently because of the envelope structure that serves to carry enzymes and to simultaneously maintain the spatial separation of photosynthesis and cellular respiration.Ins...Photosynthesis with the chloroplast works efficiently because of the envelope structure that serves to carry enzymes and to simultaneously maintain the spatial separation of photosynthesis and cellular respiration.Inspired by the spatially separated architecture,a chloroplast-like structured photocatalyst(PdS@CdS@MoS_(2)),in which the PdS and MoS_(2) function as enzymes in the chloroplast and CdS shell functions as the chloroplast envelope,was developed to improve the photocatalytic H_(2) evolution.In this unique nanoscale bionic structure,the poriferous CdS shell enhances light absorption,generates photoinduced carriers,and separates oxidation and reduction reactions.Meanwhile,PdS and MoS_(2) dual cocatalysts enhance the charge separation efficiency through forming a built-in electric field with CdS.We demonstrate that the separation efficiency of carriers,carrier lifetime,and the yield of H_(2) are both higher than that of CdS nanoparticles,evidencing the feasibility of the chloroplast-like structure in enhancing the photocatalyst activity.This work emphasizes the synergism of the three key processes of the photocatalytic reaction by simulating the chloroplast structure and provides a general synthesis strategy,the synthesis of novel structured for photocatalysts for diverse applications in the energy field.展开更多
Two-dimensional(2D)hexagonal boron nitride(hBN),due to its extraordinary thermal,chemical,and optical properties,has arisen as an enticing material for the research community to explore for various applications,includ...Two-dimensional(2D)hexagonal boron nitride(hBN),due to its extraordinary thermal,chemical,and optical properties,has arisen as an enticing material for the research community to explore for various applications,including the use of site defects in hBN as single photon emitters(SPEs).In this review,we systematically summarize recent advanced strategies towards the controllable synthesis of 2D hBN using chemical vapor deposition,towards a full control of the domain size,orientation,morphology,layer number,and stacking order,etc.Moreover,we review the underlying mechanisms for single photon emission(SPE)in hBN and methods to selectively generate and tune the SPEs.Defects(e.g.,carbon substituted defects)are discussed for the potential use as emission sites.We finally give an outlook of future challenges and opportunities on desirable hBN synthesis and further investigation of SPEs in hBN,targeting to utilize hBN as single photon emitters in an industrial scale.展开更多
The scalable growth of wafer-sized single-crystal graphene in an energy-efficient manner and compatible with wafer process is critical for the killer applications of graphene in high-performance electronics and optoel...The scalable growth of wafer-sized single-crystal graphene in an energy-efficient manner and compatible with wafer process is critical for the killer applications of graphene in high-performance electronics and optoelectronics. Here, ultrafast epitaxial growth of single-crystal graphene wafers is realized on singlecrystal Cu90Ni10(1 1 1) thin films fabricated by a tailored two-step magnetron sputtering and recrystallization process. The minor nickel(Ni) content greatly enhances the catalytic activity of Cu, rendering the growth of a 4 in. single-crystal monolayer graphene wafer in 10 min on Cu90Ni10(1 1 1), 50 folds faster than graphene growth on Cu(1 1 1). Through the carbon isotope labeling experiments, graphene growth on Cu90Ni10(1 1 1) is proved to be exclusively surface-reaction dominated, which is ascribed to the Cu surface enrichment in the Cu Ni alloy, as indicated by element in-depth profile. One of the best benefits of our protocol is the compatibility with wafer process and excellent scalability. A pilot-scale chemical vapor deposition(CVD) system is designed and built for the mass production of single-crystal graphene wafers, with productivity of 25 pieces in one process cycle. Furthermore, we demonstrate the application of single-crystal graphene in electrically controlled liquid-crystal microlens arrays(LCMLA), which exhibit highly tunable focal lengths near 2 mm under small driving voltages. By integration of the graphene based LCMLA and a CMOS sensor, a prototype camera is proposed that is available for simultaneous light-field and light intensity imaging. The single-crystal graphene wafers could hold great promising for highperformance electronics and optoelectronics that are compatible with wafer process.展开更多
Infrared(IR)light photodetection based on two dimensional(2D)materials of proper bandgap has attracted increasing attention.However,the weak IR absorption in 2D materials,due to their ultrathin attribute and indirect ...Infrared(IR)light photodetection based on two dimensional(2D)materials of proper bandgap has attracted increasing attention.However,the weak IR absorption in 2D materials,due to their ultrathin attribute and indirect bandgap in multilayer structures,degrades their performance when used as IR photodetectors.In this work,we utilize the fact that few-layer MoTe2 flake has a near-IR(NIR)bandgap and demonstrate a^60-fold enhancement of NIR response by introducing a gold hollow nanorods on the surface.Such gold hollow nanorods have distinct absorption peak located also at the NIR regime,therefore induces strong resonance,benefitting NIR absorption in MoTe2,resulting in strong near-field enhancement.With the evidence from steady and transient state optical spectra,we confirm that the enhancement of NIR response originates only photon absorption,rather than electron transport at interfaces as observed in other heterostructures,therefore,precluding the requirement of high-quality interfaces for commercial applications.展开更多
The functional recovery of peripheral nerve injury(PNI)is unsatisfactory,whereas diabetes mellitus(DM)and its related complications further attenuate the restoration of diabetic PNI(DPNI).Adipose-derived stem cells(AD...The functional recovery of peripheral nerve injury(PNI)is unsatisfactory,whereas diabetes mellitus(DM)and its related complications further attenuate the restoration of diabetic PNI(DPNI).Adipose-derived stem cells(ADSCs)are promising candidates for treatment of DPNI due to their abundant source,excellent differentiation and paracrine ability.Our results showed that ADSCs remarkably enhanced the proliferation and migration of Schwann cells and endothelial cells,and tube formation.Mechanistically,ADSCs could regulate Nrf2/HO-1,NF-κB and PI3K/AKT/mTOR signaling pathways,showing multiple functions in reducing oxidative stress and inflammation,and regulating cell metabolism,growth,survival,proliferation,angiogenesis,differentiation of Schwann cell and myelin formation.In current study,novel graphene foam(GF)/hydrogel-based scaffold was developed to deliver ADSCs for treatment of DPNI.GF/hydrogel scaffold exhibited excellent mechanical strength,suitable porous network,superior electrical conductivity,and good biocompatibility.In vitro results revealed that GF/hydrogel scaffold could obviously accelerate proliferation of Schwann cells.Moreover,in vivo experiments demonstrated that ADSCs-loaded GF/hydrogel scaffold significantly promoted the recovery of DPNI and inhibited the atrophy of targeted muscles,thus providing a novel and attractive therapeutic approach for DPNI patients.展开更多
Direct messenger ribonucleic acid(mRNA)delivery to target cells or tissues has revolutionized the field of biotechnology.However,the applicability of regenerative medicine is limited by the technical difficulties of v...Direct messenger ribonucleic acid(mRNA)delivery to target cells or tissues has revolutionized the field of biotechnology.However,the applicability of regenerative medicine is limited by the technical difficulties of various mRNA-loaded nanocarriers.Herein,we report a new conductive hybrid film that could guide osteogenic differentiation of human adipose-derived mesenchymal stem cells(hADMSCs)via electrically controlled mRNA delivery.To find optimal electrical conductivity and mRNAloading capacity,the polypyrrole-graphene oxide(PPy-GO)hybrid film was electropolymerized on indium tin oxide substrates.We found that the fluorescein sodium salt,a molecule partially mimicking the physical and chemical properties of mRNAs,can be effectively absorbed and released by electrical stimulation(ES).The hADMSCs cultivated on the PPy-GO hybrid film loaded with pre-osteogenic mRNAs showed the highest osteogenic differentiation under electrical stimulation.This platform can load various types of RNAs thus highly promising as a new nucleic acid delivery tool for the development of stem cell-based therapeutics.展开更多
In-plane anisotropy(IPA)due to asymmetry in lattice structures provides an additional parameter for the precise tuning of characteristic polarization-dependent properties in two-dimensional(2D)materials,but the narrow...In-plane anisotropy(IPA)due to asymmetry in lattice structures provides an additional parameter for the precise tuning of characteristic polarization-dependent properties in two-dimensional(2D)materials,but the narrow range within which such method can modulate properties hinders significant development of related devices.Herein we present a novel periodic phase engineering strategy that can remarkably enhance the intrinsic IPA obtainable from minor variations in asymmetric structures.By introducing alternant monoclinic and rutile phases in 2D VO_(2)single crystals through the regulation of interfacial thermal strain,the IPA in electrical conductivity can be reversibly modulated in a range spanning two orders of magnitude,reaching an unprecedented IPA of 113.Such an intriguing local phase engineering in 2D materials can be well depicted and predicted by a theoretical model consisting of phase transformation,thermal expansion,and friction force at the interface,creating a frame-work applicable to other 2D materials.Ultimately,the considerable adjustability and reversibility of the presented strategy provide opportunities for future polarization-dependent photoelectric and optoelectronic devices.展开更多
基金supported by the Gansu Provincial Development and Reform Commission(NDRC,No.2013-1336).
文摘Photosynthesis with the chloroplast works efficiently because of the envelope structure that serves to carry enzymes and to simultaneously maintain the spatial separation of photosynthesis and cellular respiration.Inspired by the spatially separated architecture,a chloroplast-like structured photocatalyst(PdS@CdS@MoS_(2)),in which the PdS and MoS_(2) function as enzymes in the chloroplast and CdS shell functions as the chloroplast envelope,was developed to improve the photocatalytic H_(2) evolution.In this unique nanoscale bionic structure,the poriferous CdS shell enhances light absorption,generates photoinduced carriers,and separates oxidation and reduction reactions.Meanwhile,PdS and MoS_(2) dual cocatalysts enhance the charge separation efficiency through forming a built-in electric field with CdS.We demonstrate that the separation efficiency of carriers,carrier lifetime,and the yield of H_(2) are both higher than that of CdS nanoparticles,evidencing the feasibility of the chloroplast-like structure in enhancing the photocatalyst activity.This work emphasizes the synergism of the three key processes of the photocatalytic reaction by simulating the chloroplast structure and provides a general synthesis strategy,the synthesis of novel structured for photocatalysts for diverse applications in the energy field.
基金Z.L.acknowledge the support from Research Grant Council of Hong Kong SAR(16304518),NSFC-RGC Joint Research Scheme(N_HKUST607/17)the Innovation and Technology Commission(ITCCNERC14SC01)+3 种基金the Zhongshan City Burea of Science and Technology(2019AG018)the IER foundation(HT-JD-CXY-201907)research fund of Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory(NO.2020B1212030010)Guangdong Provincial Department of Science and Technology(grants 2020A0505090003).
文摘Two-dimensional(2D)hexagonal boron nitride(hBN),due to its extraordinary thermal,chemical,and optical properties,has arisen as an enticing material for the research community to explore for various applications,including the use of site defects in hBN as single photon emitters(SPEs).In this review,we systematically summarize recent advanced strategies towards the controllable synthesis of 2D hBN using chemical vapor deposition,towards a full control of the domain size,orientation,morphology,layer number,and stacking order,etc.Moreover,we review the underlying mechanisms for single photon emission(SPE)in hBN and methods to selectively generate and tune the SPEs.Defects(e.g.,carbon substituted defects)are discussed for the potential use as emission sites.We finally give an outlook of future challenges and opportunities on desirable hBN synthesis and further investigation of SPEs in hBN,targeting to utilize hBN as single photon emitters in an industrial scale.
基金supported by the National Basic Research Program of China(2016YFA0200101 and 2014CB932500)the National Natural Science Foundation of China(21525310,51432002,51520105003,61432007,and 61176052)Beijing Municipal Science&Technology Commission(Z161100002116021 and Z181100004818001)
文摘The scalable growth of wafer-sized single-crystal graphene in an energy-efficient manner and compatible with wafer process is critical for the killer applications of graphene in high-performance electronics and optoelectronics. Here, ultrafast epitaxial growth of single-crystal graphene wafers is realized on singlecrystal Cu90Ni10(1 1 1) thin films fabricated by a tailored two-step magnetron sputtering and recrystallization process. The minor nickel(Ni) content greatly enhances the catalytic activity of Cu, rendering the growth of a 4 in. single-crystal monolayer graphene wafer in 10 min on Cu90Ni10(1 1 1), 50 folds faster than graphene growth on Cu(1 1 1). Through the carbon isotope labeling experiments, graphene growth on Cu90Ni10(1 1 1) is proved to be exclusively surface-reaction dominated, which is ascribed to the Cu surface enrichment in the Cu Ni alloy, as indicated by element in-depth profile. One of the best benefits of our protocol is the compatibility with wafer process and excellent scalability. A pilot-scale chemical vapor deposition(CVD) system is designed and built for the mass production of single-crystal graphene wafers, with productivity of 25 pieces in one process cycle. Furthermore, we demonstrate the application of single-crystal graphene in electrically controlled liquid-crystal microlens arrays(LCMLA), which exhibit highly tunable focal lengths near 2 mm under small driving voltages. By integration of the graphene based LCMLA and a CMOS sensor, a prototype camera is proposed that is available for simultaneous light-field and light intensity imaging. The single-crystal graphene wafers could hold great promising for highperformance electronics and optoelectronics that are compatible with wafer process.
基金This project was supported by the Research Grant Council of Hong Kong SAR(No.1620441)NSFC-RGC Joint Research Scheme(No.N_HKUST607/17)+4 种基金the Innovation and Technology Commission(No.ITC-CNERC14SC01)the Zhongshan Municipal Bureau of Science&Technology(No.ZSST19EG03)National Natural Science Foundation of China(NSFC)(Nos.11825203,51872100,21825103,21501060 and 51727809)National Basic Research Program of China(Nos.2015CB932600 and 2019kfyRCPY059)Foundation of Shenzhen Science and Technology Innovation Committee(No.JCYJ20180504170444967).
文摘Infrared(IR)light photodetection based on two dimensional(2D)materials of proper bandgap has attracted increasing attention.However,the weak IR absorption in 2D materials,due to their ultrathin attribute and indirect bandgap in multilayer structures,degrades their performance when used as IR photodetectors.In this work,we utilize the fact that few-layer MoTe2 flake has a near-IR(NIR)bandgap and demonstrate a^60-fold enhancement of NIR response by introducing a gold hollow nanorods on the surface.Such gold hollow nanorods have distinct absorption peak located also at the NIR regime,therefore induces strong resonance,benefitting NIR absorption in MoTe2,resulting in strong near-field enhancement.With the evidence from steady and transient state optical spectra,we confirm that the enhancement of NIR response originates only photon absorption,rather than electron transport at interfaces as observed in other heterostructures,therefore,precluding the requirement of high-quality interfaces for commercial applications.
基金This study is financially supported by the National Natural Science Foundation of China(Nos.81971758,51890892,81971712,81870346,and 81700432)the Natural Science Foundation of Shanghai Science and Technology Committee(No.20ZR1431600)+7 种基金This research is also supported by the National Natural Science Foundation of China(No.11761161004)Z.L.acknowledge supports by the National Natural Science Foundation of China-Research Grants Council Joint Research Scheme(Nos.11761161004 and N_HKUST607/17)the IER foundation(No.HT-JD-CXY-201907)“International science and technology cooperation projects”of Science and Technological Bureau of Guangzhou Huangpu District(No.2019GH06)Guangdong Science and Technology Department(No.2020A0505090003)Research Fund of Guangdong-Hong Kong-Macao Joint Laboratory for Intelligent Micro-Nano Optoelectronic Technology(No.2020B1212030010)Technical assistance from the Materials Characterization and Preparation Facilities of The Hong Kong University Of Science And Technology is greatly appreciatedWe also acknowledge the support of Guangdong Provincial Key Laboratory Program(No.2021B1212040001)from the Department of Science and Technology of Guangdong Province.
文摘The functional recovery of peripheral nerve injury(PNI)is unsatisfactory,whereas diabetes mellitus(DM)and its related complications further attenuate the restoration of diabetic PNI(DPNI).Adipose-derived stem cells(ADSCs)are promising candidates for treatment of DPNI due to their abundant source,excellent differentiation and paracrine ability.Our results showed that ADSCs remarkably enhanced the proliferation and migration of Schwann cells and endothelial cells,and tube formation.Mechanistically,ADSCs could regulate Nrf2/HO-1,NF-κB and PI3K/AKT/mTOR signaling pathways,showing multiple functions in reducing oxidative stress and inflammation,and regulating cell metabolism,growth,survival,proliferation,angiogenesis,differentiation of Schwann cell and myelin formation.In current study,novel graphene foam(GF)/hydrogel-based scaffold was developed to deliver ADSCs for treatment of DPNI.GF/hydrogel scaffold exhibited excellent mechanical strength,suitable porous network,superior electrical conductivity,and good biocompatibility.In vitro results revealed that GF/hydrogel scaffold could obviously accelerate proliferation of Schwann cells.Moreover,in vivo experiments demonstrated that ADSCs-loaded GF/hydrogel scaffold significantly promoted the recovery of DPNI and inhibited the atrophy of targeted muscles,thus providing a novel and attractive therapeutic approach for DPNI patients.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(Nos.NRF-2019M3A9H_(2)031820,NRF-2021R1A2C1010747,and NRF-2022R1A2C4002217)Korean Fund for Regenerative Medicine funded by Ministry of Science and ICT,and Ministry of Health and Welfare(Grant No.RS-2022-00070316)+1 种基金the Bio&Medical Technology Development Program funded by the Ministry of Science,ICT and Future Planning,Republic of Korea(NRF-2017M3A9E4047243)d K.S.also thankful for The Council of Higher Education(CoHE,100/2000)PhD Scholarship Program,Turkey.
文摘Direct messenger ribonucleic acid(mRNA)delivery to target cells or tissues has revolutionized the field of biotechnology.However,the applicability of regenerative medicine is limited by the technical difficulties of various mRNA-loaded nanocarriers.Herein,we report a new conductive hybrid film that could guide osteogenic differentiation of human adipose-derived mesenchymal stem cells(hADMSCs)via electrically controlled mRNA delivery.To find optimal electrical conductivity and mRNAloading capacity,the polypyrrole-graphene oxide(PPy-GO)hybrid film was electropolymerized on indium tin oxide substrates.We found that the fluorescein sodium salt,a molecule partially mimicking the physical and chemical properties of mRNAs,can be effectively absorbed and released by electrical stimulation(ES).The hADMSCs cultivated on the PPy-GO hybrid film loaded with pre-osteogenic mRNAs showed the highest osteogenic differentiation under electrical stimulation.This platform can load various types of RNAs thus highly promising as a new nucleic acid delivery tool for the development of stem cell-based therapeutics.
基金This work was supported by the National Natural Science Foundation of China(Grants No.51872100,21825103,and 51727809)the Institute for Basic Science(Grant No.IBS-R019-D1)of South Korea.
文摘In-plane anisotropy(IPA)due to asymmetry in lattice structures provides an additional parameter for the precise tuning of characteristic polarization-dependent properties in two-dimensional(2D)materials,but the narrow range within which such method can modulate properties hinders significant development of related devices.Herein we present a novel periodic phase engineering strategy that can remarkably enhance the intrinsic IPA obtainable from minor variations in asymmetric structures.By introducing alternant monoclinic and rutile phases in 2D VO_(2)single crystals through the regulation of interfacial thermal strain,the IPA in electrical conductivity can be reversibly modulated in a range spanning two orders of magnitude,reaching an unprecedented IPA of 113.Such an intriguing local phase engineering in 2D materials can be well depicted and predicted by a theoretical model consisting of phase transformation,thermal expansion,and friction force at the interface,creating a frame-work applicable to other 2D materials.Ultimately,the considerable adjustability and reversibility of the presented strategy provide opportunities for future polarization-dependent photoelectric and optoelectronic devices.