Showing papers by "Hong Liu published in 2017"
TL;DR: In this article, a series of Cd0.2Zn0.8S and UiO-66-NH2 nanocomposites with different contents were fabricated via a facile solvothermal method and evaluated by photocatalytic H2 evolution and CO2 reduction under visible-light irradiation.
Abstract: Metal-organic frameworks (MOFs), a new class of porous crystalline materials, have attracted great interest as fascinating materials for sustainable energy and environmental remediation. However, the functionalization and diversification of MOFs are still challenging and imperative for the development of highly active MOF-based materials. In this study, a series of Cd0.2Zn0.8S@UiO-66-NH2 nanocomposites with different UiO-66-NH2 contents were fabricated via a facile solvothermal method. The photocatalytic performances of the obtained Cd0.2Zn0.8S@UiO-66-NH2 nanocomposites were evaluated by photocatalytic H2 evolution and CO2 reduction under visible-light irradiation. The resultant hybrids exhibit significantly enhanced photocatalytic activity for hydrogen evolution and CO2 reduction as compared with pristine components, and the optimal UiO-66-NH2 content is 20 wt%. The composite can show a hydrogen evolution rate of 5846.5 μmol h−1 g−1 and a CH3OH production rate of 6.8 μmol h−1 g−1. The remarkable enhancement of the photocatalytic activity should be attributed to the efficient charge separation and transfer on the interface between Cd0.2Zn0.8S and UiO-66-NH2. Furthermore, the Cd0.2Zn0.8S@UiO-66-NH2 photocatalysts show excellent stability during photocatalytic hydrogen evolution and CO2 reduction. This work demonstrates that MOF-based composite materials hold great promise for applications in the field of energy conversion and environmental purification.
398 citations
TL;DR: Detailed electrochemical investigations andoretical calculations demonstrate that the nanosheet structure, N doping, and particular crystalline phase of Mo2C produce more exposed Mo active sites, including Mo atoms on the C plane and doped N atoms, which will facilitate the understanding and optimization of Mo-based electrocatalysts in the energy conversion field.
Abstract: Probing competent electrocatalysts for hydrogen evolution reaction (HER) of water splitting is one of the most hopeful approaches to confront the energy and environmental crisis. Herein, we highlight ultrathin N-doped Mo2C nanosheets (N-Mo2C NSs) in the role of greatly efficient platinum-free-based electrocatalysts for the HER. The transformation of crystal phase and structure between MoO2 nanosheets with a thickness of ∼1.1 nm and N-Mo2C NSs with a thickness of ∼1.0 nm is studied in detail. Structural analyses make clear that the surfaces of the N-Mo2C NSs are absolutely encompassed by apical Mo atoms, hence affording an ideal catalyst prototype to expose the role of Mo atoms for the duration of HER catalysis. Theoretical calculations demonstrate that the nanosheet structure, N doping, and particular crystalline phase of Mo2C produce more exposed Mo active sites, including Mo atoms on the C plane and doped N atoms. Through detailed electrochemical investigations, N-Mo2C NSs possess HER activity with an o...
312 citations
TL;DR: In this article, the authors summarized the progress in solar light absorption with various photocatalysts, including the most recent progress concerning light-chemical conversion mechanisms, classified as photatalytic redox and photothermal catalysis.
Abstract: The realization of light–chemical energy conversion using solar light is an ideal goal in renewable energy studies. Many reports are concerned with extracting energy from solar light and the use/storage of the converted energy. Due to the progress in solar light absorption with various photocatalysts, the various energy conversion mechanisms using different photonic energies should be summarized. Therefore, the photocatalytic work that light can achieve with a certain photonic energy range, from UV light to visible light to near-infrared light, is summarized in this review, including the most recent progress concerning light–chemical conversion mechanisms, classified as photocatalytic redox and photothermal catalysis. This review mostly concerns the mechanisms and specific strategies of light–chemical energy conversion based on various photonic energies.
194 citations
TL;DR: In this paper, a CdS/MoS2/Mo sheets system simultaneously containing photocatalysts, co-catalysts and conductive supports, was prepared via the one-step hydrothermal process by Mo sheets as template and Mo sources.
Abstract: Co-catalysts for H2 production are often made from expensive noble metals, such as the most efficient Pt. The alternative non-noble metal co-catalysts with low cost and high efficiency are therefore highly desirable for economically viable H2 production. Herein, we demonstrated that a CdS/MoS2/Mo sheets system simultaneously containing photocatalysts, co-catalysts, and conductive supports, was prepared via the one-step hydrothermal process by Mo sheets as template and Mo sources. The obtained CdS/MoS2/Mo sheets possess the superior photocatalytic H2 production via water splitting under visible light irradiation, which achieved an extraordinary H2 production of 4540 μmol h−1 g−1, up to 28.6 and 3.6 times greater than that of CdS alone and Pt/CdS. The synergetic effect of MoS2 as co-catalysts and Mo sheets as conductive supports contribute to the dramatically improved photocatalytic H2 evolution activity of CdS photocatalysts, by means of facilitating charge carriers separation and providing active sites for proton reduction. These findings provide a straightforward and practical route to produce cheap and efficient co-catalysts for large-scale water splitting.
190 citations
TL;DR: In this paper, a review of the underlying principles and key functional features of 1D 1D ribbon-like nanobelts and their heterostructures is presented, and the prospects of this type of novel hybrid photocatalyst are discussed.
Abstract: Semiconductor photocatalysis is a promising approach to combat both environmental pollution and the global energy shortage. Advanced TiO 2 -based photocatalysts with novel photoelectronic properties are benchmark materials that have been pursued for their high solar energy conversion efficiency. Among the different morphological TiO 2 nanostructures, TiO 2 nanobelts (NBs) attract more attention due to their unique physical properties and ideal 1D ribbon-like morphology that is favorable for constructing heterostructures by assembling second-phase nanoparticles on the surface of the NBs. A large number of studies have proven that well-designed TiO 2 NB heterostructures can not only broaden the photocatalytically active light band of TiO 2 but also enhance the light absorption performance and the photo-induced carrier separation ability. The TiO 2 NB heterostructure has become a versatile and powerful tool for building high-performance TiO 2 -based photocatalysts, which has stimulated intense research activities focused on the growth, properties, and applications of the 1D TiO 2 NB and its heterostructures. This review attempts to cover all these aspects, including the underlying principles and key functional features of TiO 2 NBs and TiO 2 NB heterostructures in a comprehensive way and also discuss the prospects of this type of novel hybrid photocatalyst.
189 citations
TL;DR: This study demonstrates that CAR T-cell immunotherapy targeting intracellular/secreted solid tumor antigens can elicit a potent antitumor response and offers a promising new avenue for liver cancer immunotherapy.
Abstract: Purpose: The majority of tumor-specific antigens are intracellular and/or secreted and therefore inaccessible by conventional chimeric antigen receptor (CAR) T-cell therapy. Given that all intracellular/secreted proteins are processed into peptides and presented by class I MHC on the surface of tumor cells, we used alpha-fetoprotein (AFP), a specific liver cancer marker, as an example to determine whether peptide–MHC complexes can be targets for CAR T-cell therapy against solid tumors. Experimental Design: We generated a fully human chimeric antigen receptor, ET1402L1-CAR (AFP-CAR), with exquisite selectivity and specificity for the AFP158–166 peptide complexed with human leukocyte antigen (HLA)-A*02:01. Results: We report that T cells expressing AFP-CAR selectively degranulated, released cytokines, and lysed liver cancer cells that were HLA-A*02:01+/AFP+ while sparing cells from multiple tissue types that were negative for either expressed proteins. In vivo, intratumoral injection of AFP-CAR T cells significantly regressed both Hep G2 and AFP158-expressing SK-HEP-1 tumors in SCID-Beige mice (n = 8 for each). Moreover, intravenous administration of AFP-CAR T cells in Hep G2 tumor-bearing NSG mice lead to rapid and profound tumor growth inhibition (n = 6). Finally, in an established intraperitoneal liver cancer xenograft model, AFP-CAR T cells showed robust antitumor activity (n = 6). Conclusions: This study demonstrates that CAR T-cell immunotherapy targeting intracellular/secreted solid tumor antigens can elicit a potent antitumor response. Our approach expands the spectrum of antigens available for redirected T-cell therapy against solid malignancies and offers a promising new avenue for liver cancer immunotherapy. Clin Cancer Res; 23(2); 478–88. ©2016 AACR.
152 citations
TL;DR: In this article, the effect of diffraction, shock reflection and detonation instability on the propagation of detonation is examined, and the analysis of critical length scale between the cell size and BR when the detonation fails or succeeds as it passes the obstacles is also performed.
122 citations
TL;DR: In this article, the authors synthesize yolk-shell CdS microcubes from Cd-Fe Prussian blue analogues (Cd−Fe-PBA) through a facile microwave-assisted hydrothermal process.
Abstract: Yolk–shell structures with a unique three-dimensional (3D) open architecture offer great advantages for constructing advanced photocatalysts. However, metal sulfides with yolk–shell nanostructures were rarely reported. In this work, unique yolk–shell CdS microcubes are synthesized from Cd–Fe Prussian blue analogues (Cd–Fe-PBA) through a facile microwave-assisted hydrothermal process. Their formation mechanism is also proposed based on the anion exchange and Kirkendall effect process. Benefitting from structural merits, including a 3D open structure, small size of primary nanoparticles, high specific surface area, and good structural robustness, the obtained yolk–shell CdS microcubes manifest excellent performances for photocatalytic hydrogen evolution from H2O under visible-light irradiation. The photocatalytic H2 evolution rate is 3051.4 μmol h−1 g−1 (with an apparent quantum efficiency of 4.9% at 420 nm), which is ∼2.43 times higher than that of conventional CdS nanoparticles. Furthermore, the yolk–shell CdS microcubes exhibit remarkable photocatalytic stability. This work demonstrates that MOF-derived yolk–shell structured materials hold great promise for application in the field of energy conversion.
109 citations
TL;DR: In this paper, the authors report ruthenium(II)-catalyzed redox-neutral annulation of benzamides and propargyl alcohols, in which propargy alcohols act as one-carbon units.
Abstract: Internal alkynes have been used widely in transition-metal-catalyzed cycloaddition reactions, in which they generally serve as two-carbon reaction partners. Herein, we report ruthenium(II)-catalyzed redox-neutral [4 + 1] annulation of benzamides and propargyl alcohols, in which propargyl alcohols act as one-carbon units. This synthetic utility of propargyl alcohols led to a series of potentially bioactive N-substituted quaternary isoindolinones with moderate to high yields under mild conditions. Without the requirement for an external metal oxidant, this title transformation is compatible with various functional groups, which further underscores its synthetic utility and versatile applicability. In addition, preliminary mechanism experiments have been conducted and a plausible mechanism is proposed.
104 citations
TL;DR: Rhodium(III)-catalyzed C-H activation/subsequent [4 + 1] cyclization reactions between benzamides and propargyl alcohols are reported in which propargy alcohols serve as unusual one-carbon units, leading to a series of isoindolinones bearing a quaternary carbon with moderate to good yields without the requirement for external metal oxidants.
100 citations
TL;DR: In this article, a hierarchical porous carbon rods composed of cross-linked carbon networks (Mo 2 C/CLCN) was synthesized by using Cu-MoO 2 rods as Mo source and Cu template.
TL;DR: Insightful insights are provided for a better understanding of the mechanisms of aspirin in anticancer effects, and a direction for the development of small-molecule inhibitors of heparanase is offered.
Abstract: Purpose: Recent epidemiological and clinical studies have suggested the benefit of aspirin for patients with cancer, which inspired increasing efforts to demonstrate the anticancer ability of aspirin and reveal the molecular mechanisms behind. Nevertheless, the anticancer activity and related mechanisms of aspirin remain largely unknown. This study aimed to confirm this observation, and more importantly, to investigate the potential target contributed to the anticancer of aspirin.Experimental Design: A homogeneous time-resolved fluorescence (HTRF) assay was used to examine the impact of aspirin on heparanase. Streptavidin pull-down, surface plasmon resonance (SPR) assay, and molecular docking were performed to identify heparanase as an aspirin-binding protein. Transwell, rat aortic rings, and chicken chorioallantoic membrane model were used to evaluate the antimetastasis and anti-angiogenesis effects of aspirin, and these phenotypes were tested in a B16F10 metastatic model, MDA-MB-231 metastatic model, and MDA-MB-435 xenograft model.Results: This study identified heparanase, an oncogenic extracellular matrix enzyme involved in cancer metastasis and angiogenesis, as a potential target of aspirin. We had discovered that aspirin directly binds to Glu225 region of heparanase and inhibits the enzymatic activity. Aspirin impeded tumor metastasis, angiogenesis, and growth in heparanase-dependent manner.Conclusions: In summary, this study has illustrated heparanase as a target of aspirin for the first time. It provides insights for a better understanding of the mechanisms of aspirin in anticancer effects, and offers a direction for the development of small-molecule inhibitors of heparanase. Clin Cancer Res; 23(20); 6267-78. ©2017 AACR.
TL;DR: The findings indicate that the flexible, mechanically strong, surface nanoporous, biodegradable, and cytocompatible nanostructured rGO microfibers not only offer a more powerful substrate for NSCs adhesion and proliferation compared with 2D graphene film and tissue cluture plate but also regulate the NSC's differentiation into neurons and form a dense neural network surrounding the microfiber.
Abstract: We report the cytocompatibility and regulating effects of the nanostructured reduced graphene oxide (rGO) microfibers, which are synthesized through a capillary hydrothermal method, on neural differentiation of neural stem cells (NSCs). Our findings indicate that the flexible, mechanically strong, surface nanoporous, biodegradable, and cytocompatible nanostructured rGO microfibers not only offer a more powerful substrate for NSCs adhesion and proliferation compared with 2D graphene film and tissue cluture plate but also regulate the NSCs differentiation into neurons and form a dense neural network surrounding the microfiber. These results illustrate the great potential of nanostructured rGO microfibers as an artificial neural tissue engineering (NTE) scaffold for nerve regeneration.
TL;DR: In this paper, a micro pseudo-electrochemical polymerization reaction was proposed for in situ synthesis of polyaniline (PANI) on the surface of BaTiO 3 nanocubes to form a core-shell nanocube.
TL;DR: In this article, an array of ferroelectric nanowires for photoelectrochemical (PEC) hydrogen production was demonstrated. And the poling bias was manipulated to tune the photocurrent density in the range from ca. 0.7 − 11.5 μA·cm−2 (at 0 −V vs. Ag/AgCl) under irradiation of air mass 1.5 global (AM 1 −1.5 G) full sunlight at 100 mW/cm2, while the onset potential switches from −0.32 to − 0.46
TL;DR: This review article critically discusses examples of asymmetric synthesis of tailor-made α-amino acids via homologation of Ni(II) complexes of glycine and alanine Schiff bases, reported in the literature from 2013 through the end of 2016.
Abstract: This review article critically discusses examples of asymmetric synthesis of tailor-made α-amino acids via homologation of Ni(II) complexes of glycine and alanine Schiff bases, reported in the literature from 2013 through the end of 2016. Where it is possible, reaction mechanism and origin of the stereochemical outcome is discussed in detail. Special attention is given to various aspects of practicality and scalability of the reported methods. Among the most noticeable developments in this area are novel designs of axially chiral ligands, application of electro- and mechano-chemical (ball-milling) conditions, and development of dynamic kinetic resolution procedures.
TL;DR: In this article, two types of bio-wastes, Platanus fruit and willow catkins, were used to prepare hollow carbon micro-fibers, where their size and microstructure are dependent on the Platanus fibre fibers andwillow catkin fibers.
Abstract: Normally, structural details of the tissue of bio-waste affect the final properties of carbon materials. In this study, we selected two types of bio-wastes, Platanus fruit and willow catkins, to prepare hollow carbon micro-fibers, where their size and microstructure are dependent on the Platanus fruit fibers and willow catkin fibers. The electrode properties of the Platanus-derived hollow micro carbon fibers are much higher than those of the willow-derived micro carbon fibers, although carbonization and activation processes are the same for the two types of materials. It is found that the content of the organic-related elements, C, N, and S, and the content of inorganic ions, K or Na, are different. The high content of N and S induced a high doping concentration of the hollow carbon micro-fibers, which endows the Platanus-derived carbon materials with high conductivity, and the high content of inorganic elements causes a self-activation effect during the carbonization process and results in a special porous microstructure of the Platanus-derived carbon. Therefore, compared with the willow-derived hollow carbon micro-fibers, after carbonization and KOH activation, the hollow carbon micro-fibers derived from Platanus seeds possessed much higher supercapacitor electrode properties. After carbonization and activation under optimized conditions, the specific capacitance of the Platanus- and willow-derived hollow carbon micro-fibers are 304.65 F g−1 and 276.13 F g−1, respectively, at the current density of 0.5 A g−1, with a good rate capability and 88.5% and 81.05% capacity retention at 10 A g−1, respectively. The coin-type symmetric device of these two samples with 6 M KOH electrolyte exhibited a high specific capacitance of 286.5 and 267.5 F g−1, respectively, at 0.25 A g−1 (PFs 900, WFs 800), with an excellent cycling stability and 97.03% and 91.12% capacity retention after 10000 cycles, respectively. This work not only provided two types of promising supercapacitor carbon materials but also, most importantly, offered us clues for the design and synthesis of high-performance electrode materials using the knowledge gleaned from nature.
TL;DR: A Cp*Rh(III)-catalyzed directed C−H methylation of quinoline N-oxides at the C-8 position using commercially available organotrifluoroborates as reagents features perfect regioselectivity, relatively mild reaction conditions, and diverse functional group tolerance with good to excellent yields.
Abstract: Herein, we report a Cp*Rh(III)-catalyzed directed C−H methylation of quinoline N-oxides at the C-8 position using commercially available organotrifluoroborates as reagents. This method features perfect regioselectivity, relatively mild reaction conditions, and diverse functional group tolerance with good to excellent yields. Additionally, direct C-8 arylated quinoline N-oxides products could also be obtained under the same conditions. Preliminary mechanistic experiments were conducted and a possible mechanism was proposed.
TL;DR: In this paper, as-received and pre-coated SiC whiskers (SiC w )/SiC ceramics were prepared by phenolic resin molding and reaction sintering at 1650°C.
TL;DR: In this paper, hierarchical porous carbon with highly ordered straight micro-channels was prepared using a facile melt vacuum infiltration method using continuous filament glass fiber arrays as the template and glucose as the precursor.
Abstract: Hierarchical porous carbon with highly ordered straight micro-channels was prepared though a facile melt vacuum infiltration method using continuous filament glass fiber arrays as the template and glucose as the precursor. The as-prepared carbon material shows high specific surface areas up to 1880 m2 g−1 profited from the unique structure of straight micro-channels. A fine pore structure is formed in the channel wall through KOH activation after the removal of the glass fiber array. Electrochemical evaluation of the carbon material indicates that the hierarchical porous carbon exhibits a high specific capacitance of 283 F g−1 at a current density of 0.25 A g−1 with an alkaline electrolyte (6 M KOH) in a three-electrode system. It also demonstrates excellent cycling stability with a capacity retention of 88.5% over 10 000 cycles at a high current density of 6 A g−1. These exciting results demonstrate a very simple and low-cost method for large-scale preparation of electrode materials for supercapacitors.
TL;DR: In this paper, a novel, facile, and one-step hydrothermal approach was developed to synthesize urchin-like anatase TiO2 hierarchical nanostructures assembled from ultrathin nanobelts using urea as the morphology-directing agent.
Abstract: Nanostructured TiO2 materials with a controlled morphology and structure have drawn considerable attention to both fundamental research and practical applications owing to their unique characteristics. Herein, a novel, facile, and one-step hydrothermal approach was developed to synthesize urchin-like anatase TiO2 hierarchical nanostructures assembled from ultrathin nanobelts using urea as the morphology-directing agent. The effects of the urea concentration in the preparation process were discussed intensively. Photocatalytic experiments showed that the urchin-like anatase TiO2 nanostructures possessed a much higher degradation rate of methyl orange and phenol than the most successful commercial semiconductor photocatalyst P25. The reasons for the highly efficient photocatalytic activity was ascribed to the high specific surface area (171 m2 g−1) and ultrathin 1D nanobelts of anatase TiO2 self-assembled into the urchin-like hollow spheres. The urchin-like anatase TiO2 nanostructures as photocatalysts have potential applications in environmental and energy fields for photocatalytic degradation, hydrogen production, Li-ion batteries, and dye-sensitized solar cells. In addition, new hydrothermal method can be developed for synthesis of other hierarchical nanostructures.
TL;DR: The diboration of alkynes has become the most straightforward and powerful method for the synthesis of functionalized 1,2-diborylalkenes, which are widely used as building blocks in organic synthesis.
Abstract: The diboration of alkynes has become the most straightforward and powerful method for the synthesis of functionalized 1,2-diborylalkenes, which are widely used as building blocks in organic synthesis. The present review provides a comprehensive summary of the diboration of alkynes, including platinum-, palladium-, cobalt-, copper-, iridium-, gold-, iron-, base- and small organic molecule-catalyzed diboration, direct and metal-free diboration, and base-promoted diboration of alkynes up to early 2017. The reaction conditions, regio- and stereoselectivities, and mechanisms are summarized in detail. Moreover, synthetic applications and perspectives on the diboration of alkynes are also discussed.
TL;DR: The construct promoted proliferation and accelerated osteogenic differentiation of rBMSCs, and would be prosperous for their further applications.
TL;DR: It is revealed that miR‐503‐5p functions as the mechano‐sensitive miRNA and inhibits BMSCs osteogenic differentiation subjected to mechanical stretch and bone formation in OTM tension sides.
TL;DR: An insight is offered into key areas in which the marriage of neuroscience and nanotechnology has revolutionized the industry, including the entrance of nanotechnology into future research arenas including optogenetics, molecular/ion sensing and monitoring, and piezoelectric effects.
Abstract: Unlocking the secrets of the brain is a task fraught with complexity and challenge – not least due to the intricacy of the circuits involved. With advancements in the scale and precision of scientific technologies, we are increasingly equipped to explore how these components interact to produce a vast range of outputs that constitute function and disease. Here, an insight is offered into key areas in which the marriage of neuroscience and nanotechnology has revolutionized the industry. The evolution of ever more sophisticated nanomaterials culminates in network-operant functionalized agents. In turn, these materials contribute to novel diagnostic and therapeutic strategies, including drug delivery, neuroprotection, neural regeneration, neuroimaging and neurosurgery. Further, the entrance of nanotechnology into future research arenas including optogenetics, molecular/ion sensing and monitoring, and piezoelectric effects is discussed. Finally, considerations in nanoneurotoxicity, the main barrier to clinical translation, are reviewed, and direction for future perspectives is provided.
TL;DR: Ru(II)-catalyzed redox-neutral [3+2] annulation reactions of N-ethoxycarbamoyl indoles and internal alkynes via C-H bond activation are reported, featuring a broad internal alkyne scope, good to excellent regioselectivity, diverse functional group tolerance, and mild reaction conditions.
Abstract: Ru(II)-catalyzed redox-neutral [3+2] annulation reactions of N-ethoxycarbamoyl indoles and internal alkynes via C–H bond activation are reported. This method features a broad internal alkyne scope, including various aryl/alkyl-, alkyl/alkyl-, and diaryl-substituted alkynes, good to excellent regioselectivity, diverse functional group tolerance, and mild reaction conditions. The N-ethoxycarbamoyl directing group, temperature, CsOAc, and ruthenium catalyst proved to be crucial for conversion and high regioselectivity. Additionally, preliminary mechanistic experiments were conducted, and a possible mechanism was proposed.
TL;DR: The pseudopaper ELISA based on patterned photonic nitrocellulose is promising for sensitive, high-throughput bioanalysis and reduces the consumption of sample and reagent by 33 times compared with conventional ELISA.
Abstract: We report an enzyme-link immunosorbent assay (ELISA) based on patterned pseudopaper that is made of photonic nitrocellulose for highly sensitive fluorescence bioanalysis. The pseudopaper is fabricated using self-assembled monodisperse SiO2 nanoparticles that are patterned on a polypropylene substrate as template. The self-assembled nanoparticles have a close-packed hexagonal (opal) structure, so the resulting nitrocellulose has a complementary (inverse opal) photonic structure. Owing to the slow-photon effect of the photonic structure, fluorescence emission for ELISA is enhanced by up to 57-fold without increasing the assay time or complexity. As the detection signal is significantly amplified, a simple smartphone camera suffices to serve as the detector for rapid and on-site analysis. As a demonstration, human IgG is quantitatively analyzed with a detection limit of 3.8 fg/mL, which is lower than that of conventional ELISA and paper-based ELISA. The consumption of sample and reagent is also reduced by 33...
01 May 2017
TL;DR: These films are used as a new biocompatible platform for promoting neural stem cell (NSC) differentiation and exhibit significantly positive effects on NSC attachment and proliferation without measurable toxicity.
Abstract: Physical cues from nanostructured biomaterials have been shown to possess regulating effects on stem cell fate. In this study, nanostructured molybdenum disulfide (MoS2 ) thin films (MTFs) are prepared by assembling MoS2 nanosheets on a flat substrate. These films are used as a new biocompatible platform for promoting neural stem cell (NSC) differentiation. The results show that the nanostructured MTFs exhibit significantly positive effects on NSC attachment and proliferation without measurable toxicity. More importantly, immunostaining and real-time polymerase chain reaction assessments show that the nanostructured MTFs induce NSC differentiation into neural cells at higher efficiency. It is found that the MTFs have a good electrical conductivity and offer larger surface areas for NSC attachment and spreading compared with conventional tissue culture plates. Furthermore, multilayered cylindrical 3D living scaffolds are constructed by rolling up NSC-cultured MoS2 -polyvinylidene fluoride (PVDF) nanofiber films that are prepared by chemically assembling MoS2 nanostructures on electrospun PVDF flexible films. These living nerve scaffolds have a great potential for applications in nerve regeneration as cylindrical 3D living scaffolds.
TL;DR: Hydroxyapatite nanostructure mediated stem cell osteogenic differentiation excluding growth factors provides a powerful cue to design biomaterials with special nanostructures, and helps to elucidate the interaction of stem cell and biomaterialS nanoststructures.
Abstract: It is well-accepted that most osteogenic differentiation processes do need growth factors assistance to improve efficiency. As a material cue, hydroxyapatite (HAp) can promote osteogenic differentiation of stem cells only in a way. Up to now, rare work related to the relationship between HAp nanostructures and stem cells in osteogenic differentiation process without the assistance of growth factors has been reported. In this study, one-dimensional (1D) HAp nanostructures with tunable length were synthesized by an oleic acid assisted solvothermal method by adjusting the alcohol/water ratio (η). The morphology of 1D HAp nanostructures can be changed from long nanowires into nanorods with the η value change. Different substrates constructed by 1D HAp nanostructures were prepared to investigate the effect of morphology of nanostructured HAp on stem cell fate without any growth factors or differentiation induce media. Human adipose-derived stem cells (hADSCs), a kind of promising stem cell for autologous stem cell tissue engineering, were used as the stem cell model. The experiments prove that HAp morphology can determine the performance of hADSCs cultured on different substrates. Substrate constructed by HAp nanorods (100 nm) is of little benefit to osteogenic differentiations. Substrate constructed on HAp long nanowires (50 μm) causes growth and spread inhibition of hADSCs, which even causes most cells death after 7 days of culture. However, substrate constructed by HAp short nanowires (5 μm) can destine the hADSCs differentiation to osteoblasts efficiently in normal medium (after 3 weeks) without any growth factors. It is surprise that hADSCs have changed to polyhedral morphology and exhibited the tendency to osteogenic differentiation after only 24 h culture. Hydroxyapatite nanostructures mediated stem cell osteogenic differentiation excluding growth factors provides a powerful cue to design biomaterials with special nanostructures, and helps to elucidate the interaction of stem cell and biomaterials nanostructures. The results from this study are promising for application in bone tissue engineering.
TL;DR: The hydrophilic CQD-HAp hybrid nanorods have prolonged fluorescence life, and exhibit a higher fluorescence quantum yield than pure CQDs, and can more efficiently kill human cervical cancer cells, rather than human prostatic cancer cells.
Abstract: Carbon quantum dots (CQDs) are a new type of fluorescent nanoparticle for cell imaging and tracking However, they would easily diffuse and quench, followed by the loss of their fluorescence ability By connecting their functional groups with other nanoparticles, the CQDs will be protected from destruction and exhibit long-time fluorescence Here, carbon quantum dot-hydroxyapatite (CQD-HAp) hybrid nanorods were prepared by the self-assembly of CQDs on the surface of HAp nanorods through a facile one-pot process The morphology and size of the CQD-HAp hybrid nanorods can be well controlled by using oleic acid, which meanwhile is the source of CQDs The hydrophilic CQD-HAp hybrid nanorods have prolonged fluorescence life due to the connection between CQDs and HAp nanorods, and exhibit a higher fluorescence quantum yield than pure CQDs In addition, when hybrid nanorods load doxorubicin (Dox) to form Dox-CQD-HAp hybrid nanorods, they can more efficiently kill human cervical cancer (HeLa) cells, rather than human prostatic cancer (PC-3) cells Long time fluorescence for cell imaging and high efficiency in killing cancer cells as a drug-delivery medium make CQD-HAp hybrid nanorods have great potential applications in the bio-field