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1.
Small ; 20(26): e2310414, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38294968

RESUMO

As opposed to natural photosynthesis, a significant challenge in a semiconductor-based photocatalyst is the limited hole extraction efficiency, which adversely affects solar-to-fuel efficiency. Recent studies have demonstrated that photocatalysts featuring spatially isolated dual catalytic oxidation/reduction sites can yield enhanced hole extraction efficiencies. However, the decay dynamics of excited states in such photocatalysts have not been explored. Here a ternary barbell-shaped CdS/MoS2/Cu2S heterostructure is prepared, comprising CdS nanorods (NRs) interfaced with MoS2 nanosheets at both ends and Cu2S nanoparticles on the sidewall. By using transient absorption (TA) spectra, highly efficient charge separation within the CdS/MoS2/Cu2S heterostructure are identified. This is achieved through directed electron transfer to the MoS2 tips at a rate constant of >8.3 × 109 s-1 and rapid hole transfer to the Cu2S nanoparticles on the sidewall at a rate of >6.1 × 1010 s-1, leading to an exceptional overall charge transfer constant of 2.3 × 1011 s-1 in CdS/MoS2/Cu2S. The enhanced hole transfer efficiency results in a remarkably prolonged charge-separated state, facilitating efficient electron accumulation within the MoS2 tips. Consequently, the ternary CdS/MoS2/Cu2S heterostructure demonstrates a 22-fold enhancement in visible-light-driven H2 generation compare to pure CdS nanorods. This work highlights the significance of efficient hole extraction in enhancing the solar-to-H2 performance of semiconductor-based heterostructure.

2.
Small ; 19(18): e2207173, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36740721

RESUMO

The relatively short-lived excited states, such as the nascent electron-hole pairs (excitons) and the shallow trapping states, in semiconductor-based photocatalysts produce an exceptionally high charge carrier recombination rate, dominating a low solar-to-fuel performance. Here, a π-conjugated in-plane heterostructure between graphitic carbon nitride (g-CN) and carbon rings (Crings ) (labeling g-CN/Crings ) is effectively synthesized from the thermolysis of melamine-citric acid aggregates via a microwave-assisted heating process. The g-CN/Crings in-plane heterostructure shows remarkably suppressed excited-state decay and increased charge carrier population in photocatalysis. Kinetics analysis from the femtosecond time-resolved transient absorption spectroscopy illustrates that the g-CN/Crings π-conjugated heterostructure produces slower exciton annihilation (τ1  = 7.9 ps) and longer shallow electron trapping (τ2  = 407.1 ps) than pristine g-CN (τ1  = 3.6 ps, τ2  = 264.1 ps) owing to Crings incorporation, both of which enable more photoinduced electrons to participate in the photocatalytic reactions, thereby realizing photoactivity enhancement. As a result, the photocatalytic activity exhibits an eightfold enhancement in visible-light-driven H2 generation. This work provides a viable route of constructing π-conjugated in-plane heterostructures to suppress the excited-state decay and improve the photocatalytic performance.

3.
Small ; 19(33): e2301017, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37066713

RESUMO

Semiconductor-based heterostructures have exhibited great promise as a photocatalyst to convert solar energy into sustainable chemical fuels, however, their solar-to-fuel efficiency is largely restricted by insufficient interfacial charge separation and limited catalytically active sites. Here the integration of high-efficiency interfacial charge separation and sufficient single-atom metal active sites in a 2D van der Waals (vdW) heterostructure between ultrathin polymeric carbon nitride (p-CN) and Ni-containing Salphen-based covalent organic framework (Ni-COF) nanosheets is illustrated. The results reveal a NiN2 O2 chemical bonding in NiCOF nanosheets, leading to a highly separated single-atom Ni sites, which will function as the catalytically active sites to boost solar fuel production, as confirmed by X-ray absorption spectra and density functional theory calculations. Using ultrafast femtosecond transient adsorption (fs-TA) spectra, it shows that the vdW p-CN/Ni-COF heterostructure exhibits a faster decay lifetime of the exciton annihilation (τ = 18.3 ps) compared to that of neat p-CN (32.6 ps), illustrating an efficiently accelerated electron transfer across the vdW heterointerface from p-CN to Ni-COF, which thus allows more active electrons available to participate in the subsequent reduction reactions. The photocatalytic results offer a chemical fuel generation rate of 2.29 mmol g-1 h-1 for H2 and 6.2 µmol g-1 h-1 for CO, ≈127 and three times higher than that of neat p-CN, respectively. This work provides new insights into the construction of a π-conjugated vdW heterostructure on promoting interfacial charge separation for high-efficiency photocatalysis.

4.
Environ Sci Technol ; 57(11): 4481-4491, 2023 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-36881938

RESUMO

The effects of sex and pregnancy on the bioaccumulation and tissue distribution of legacy and emerging per- and polyfluoroalkyl substances (PFASs) in Chinese water snakes were investigated. The bioaccumulation factor of PFASs showed a positive correlation with their protein-water partition coefficients (log KPW), and steric hindrance effects were observed when the molecular volume was > 357 Å3. PFAS levels in females were significantly lower than those in males. The chemical composition of pregnant females was significantly different from that of non-pregnant females and males. The maternal transfer efficiencies of perfluorooctane sulfonic acid were higher than those of other PFASs, and a positive correlation between the maternal transfer potential and log KPW was observed for other PFASs. Tissues with high phospholipid content exhibited higher concentrations of ∑PFASs. Numerous physiological changes occurred in maternal organ systems during pregnancy, leading to the re-distribution of chemicals among different tissues. The change in tissue distribution of PFASs that are easily and not-so-easily maternally transferred was in the opposite direction. The extent of compound transfer from the liver to the egg determined tissue re-distribution during pregnancy.


Assuntos
Ácidos Alcanossulfônicos , Fluorocarbonos , Poluentes Químicos da Água , Feminino , Gravidez , Humanos , Bioacumulação , Distribuição Tecidual , Poluentes Químicos da Água/análise , Água , Fluorocarbonos/análise , China
5.
Nano Lett ; 22(9): 3825-3831, 2022 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-35499361

RESUMO

Conductive polymers (CPs) are promising biomaterials to address signal connection at biointerfaces for tissue regeneration. However, regulating material microstructure at the subcellular scale to provide a more seamless interface between conductive substrates and cells remains a great challenge. Here, we demonstrate that chemical factors and enzyme-carried subcellular structures at lesion site provide a natural bioreactor to self-assemble conductive microvesicles (CMVs) for improving bioelectrical signal reconstruction. The synthesized CMVs contribute to the electrical conduction of the injured nerve in the early stage. Moreover, CMVs are eventually expelled via lymphatic capillary to minimize space-occupying and chronic inflammation. Therefore, we provide a prototype to integrate specific physiological microenvironments and polymer chemistry to manufacture subcellular functional materials with self-adaptive interface in vivo for biomedical applications.


Assuntos
Polímeros , Engenharia Tecidual , Materiais Biocompatíveis/química , Condutividade Elétrica , Estresse Oxidativo
6.
Nature ; 537(7620): 412-428, 2016 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-27501245

RESUMO

During chronic viral infection, virus-specific CD8(+) T cells become exhausted, exhibit poor effector function and lose memory potential. However, exhausted CD8(+) T cells can still contain viral replication in chronic infections, although the mechanism of this containment is largely unknown. Here we show that a subset of exhausted CD8(+) T cells expressing the chemokine receptor CXCR5 has a critical role in the control of viral replication in mice that were chronically infected with lymphocytic choriomeningitis virus (LCMV). These CXCR5(+) CD8(+) T cells were able to migrate into B-cell follicles, expressed lower levels of inhibitory receptors and exhibited more potent cytotoxicity than the CXCR5(-) [corrected] subset. Furthermore, we identified the Id2-E2A signalling axis as an important regulator of the generation of this subset. In patients with HIV, we also identified a virus-specific CXCR5(+) CD8(+) T-cell subset, and its number was inversely correlated with viral load. The CXCR5(+) subset showed greater therapeutic potential than the CXCR5(-) [corrected] subset when adoptively transferred to chronically infected mice, and exhibited synergistic reduction of viral load when combined with anti-PD-L1 treatment. This study defines a unique subset of exhausted CD8(+) T cells that has a pivotal role in the control of viral replication during chronic viral infection.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Centro Germinativo/citologia , Coriomeningite Linfocítica/imunologia , Coriomeningite Linfocítica/virologia , Vírus da Coriomeningite Linfocítica/imunologia , Receptores CXCR5/metabolismo , Transferência Adotiva , Animais , Linfócitos B/imunologia , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/transplante , Diferenciação Celular , Doença Crônica , Feminino , Centro Germinativo/imunologia , Infecções por HIV/imunologia , Infecções por HIV/virologia , Humanos , Proteína 2 Inibidora de Diferenciação/metabolismo , Vírus da Coriomeningite Linfocítica/crescimento & desenvolvimento , Masculino , Camundongos , Receptores CXCR5/deficiência , Transdução de Sinais , Subpopulações de Linfócitos T/citologia , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Subpopulações de Linfócitos T/transplante , Carga Viral/imunologia , Replicação Viral/imunologia
7.
Nanotechnology ; 32(14): 145302, 2021 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-33108771

RESUMO

We present a template-assisted fabrication method for a large-scale ordered arrays of ZnO nanorods (ZnO-NRs) modified with Ag nanoparticles (Ag-NPs), which possess high-density three-dimensional (3D) hot spots uniformly dispersed all over the substrate, being beneficial to ultrahigh sensitivity of surface enhanced Raman scattering (SERS) detection. These achieved Ag-NPs@ZnO-NRs arrays show high sensitivity, good spectral uniformity and reproducibility as substrates for SERS detection. Using the arrays, both dye molecules (rhodamine 6G, R6G) and organic pollutants like toxic pesticides (thiram and methyl parathion) are detected, with the detection limits of thiram and methyl parathion being 0.79 × 10-9 M and 1.51 × 10-8 M, respectively. In addition, the Ag-NPs@ZnO-NRs arrays have a self-cleaning function because the analyte molecules can be photocatalytic degraded using ultraviolet irradiation, showing that the 3D recyclable arrays have promising opportunities to be applied in rapid SERS-based detection of toxic organic pesticides.

8.
Environ Sci Technol ; 55(11): 7731-7740, 2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-34003641

RESUMO

In this study, the carbon and chlorine isotope fractionation during ultraviolet-photolysis of polychlorinated biphenyls (PCBs, including PCB18, PCB77, PCB110, and PCB138) in n-hexane (Hex), methanol/water (MeOH/H2O), and silica gel was first investigated to explore their mechanistic processes. We observed a significant variation in ΛCl-C (εCl/εC) for the same PCBs in different photochemical systems, implying that PCB degradation processes in various photoreaction systems could differ. Although all substrates showed normal apparent carbon/chlorine kinetic isotope effects (C-/Cl-AKIE >1), the putative inverse C-AKIE of nondechlorinated pathways was suggested by 13C depletion of the average carbon isotope composition of PCB138 and corresponding dechlorinated products in MeOH/H2O, which might originate from the magnetic isotope effect. Significant negative correlations were found between C-AKIE and relative disappearance quantum yields ("Φ") of ortho-dechlorinated substrates (PCB18, PCB110, and PCB138) in Hex and MeOH/H2O. However, the C-AKIE and "Φ" of PCB77 (meta/para-dechlorinated congener) obviously deviated from the above correlations. Furthermore, significantly different product-related carbon isotope enrichment factors of PCB77 in Hex were found. These results demonstrated the existence of dechlorination position-specific and masking effects in carbon isotope fractionations.


Assuntos
Bifenilos Policlorados , Carbono , Isótopos de Carbono , Fracionamento Químico , Cloro
9.
Nanotechnology ; 31(20): 205303, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-31995539

RESUMO

It is of great significance to develop a simple and effective method for constructing large-scale high-quality surface-enhanced Raman scattering (SERS) substrate. Here, an Ag nanoparticle-assembled micro-bowl array was prepared by a close-packed polystyrene (PS) sphere monolayer templated electrodeposition approach. The fabricated Ag nanoparticle-assembled micro-bowl array shows high SERS sensitivity to rhodamine 6G (R6G) under an ultra-low concentration of 1 fM, and exhibits excellent SERS spectral uniformity with a small relative standard deviation (RSD) of 7.6% and good reproducibility (a RSD ∼8.2% for the average peak intensities from different batches of SERS substrates). The fabricated micro-bowl array SERS substrate was employed to detect pesticide residue (thiram and methyl parathion) on vegetables. The limit of detections (LODs) for the two pesticides are lower than the maximum residue limits (MRLs) set by the European Union respectively, showing promising application in rapid inspection of food safety.

10.
J Cell Physiol ; 234(6): 8788-8796, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30317606

RESUMO

The in vitro and in vivo effects of physalin D on macrophage M1/M2 polarization were investigated. In silico analysis was first performed for biological function prediction of different physalins. The results suggest physalins have similar predicted biological functions due to their similarities in chemical structures. The cytotoxicity of physalins was then analyzed based on cell apoptosis rate and cell viability evaluation. Physalin D was chosen for further study due to its minimal cytotoxicity. Bone marrow macrophages were isolated and induced with lipopolysaccharide/interferon (IFN)-γ for M1 polarization and interleukin (IL)-4/IL-13 for M2 polarization. The results showed that physalin D can repolarize M1 phenotype cells toward M2 phenotype. In addition, physalin D is protective in M2 macrophages to maintain the M2 phenotype in the presence of IFN-γ. On the molecular level, we found that physalin D suppressed the signal transducers and activators of transcription (STAT)1 activation and blocked STAT1 nuclear translocation. Conversely, physalin D can also activate STAT6 and enhance STAT6 nuclear translocation for M2 polarization. Taken together, these results suggested that physalin D regulates macrophage M1/M2 polarization via the STAT1/6 pathway.


Assuntos
Macrófagos/efeitos dos fármacos , Fator de Transcrição STAT1/metabolismo , Fator de Transcrição STAT6/metabolismo , Secoesteroides/farmacologia , Animais , Regulação da Expressão Gênica/efeitos dos fármacos , Terapia de Imunossupressão , Inflamação , Lipopolissacarídeos/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Estrutura Molecular , Fator de Transcrição STAT1/genética , Fator de Transcrição STAT6/genética , Secoesteroides/química
12.
J Surg Res ; 205(2): 464-473, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27664897

RESUMO

BACKGROUND: Mesenchymal stem cell (MSC) transplantation is an effective treatment therapy for ischemic ulcers. However, in high-glucose microenvironment, the original inflammation-inhibiting function of MSCs leads to turns into secreting large amounts of inflammatory mediators, such as tumor necrosis factor alpha, for example, which decreases their capacity and becomes poor quality stem cells over inflammation cells for diabetic foot ulcers repair in the healing of diabetic foot ulcers. Erythropoietin (EPO) is an anti-inflammatory, proangiogenic cytokine. It is unclear whether EPO-activated MSCs with biomaterials can promote the effective healing of diabetic foot ulcers. METHODS: Cultivated MSCs in MSC-L, MSC-H, EPO-G, Akt-G, and mTOR-G, then separated the supernatant-conditioned medium of these groups to stimulate human umbilical vein endothelial cells on proliferation and migration experiments; a new type of biomaterial planted with the EPO-activated MSCs was applied to the diabetic foot ulcers of the C57 mice. RESULTS: In vitro experiments showed that EPO could stimulate MSCs to secrete vascular endothelial growth factor in high-glucose microenvironment. More importantly, EPO could reduce the damage to MSCs by high-glucose microenvironment, promote their proliferation and migration functions, and inhibit the high-glucose-induced MSCs from secreting the inflammatory mediator tumor necrosis factor alpha. In vivo experiments showed greater angiogenesis in EPO-MSC group than in control group, ulcer healing in EPO-MSC group was significantly better than that in control group, and MSCs partially differentiated into endothelial cells. EPO-activated MSCs could inhibit the monocyte invasion of localized diabetic foot ulcers. CONCLUSIONS: Our results indicate that EPO-activated MSCs can promote the effective healing of diabetic foot ulcers. The mechanism is that EPO can change stem cells from excessive inflammation into general inflammation and improved diabetic foot ulcers inflammatory microenvironment.


Assuntos
Microambiente Celular/fisiologia , Pé Diabético/terapia , Eritropoetina/metabolismo , Transplante de Células-Tronco Mesenquimais/métodos , Células-Tronco Mesenquimais/metabolismo , Cicatrização/fisiologia , Animais , Biomarcadores/metabolismo , Movimento Celular , Proliferação de Células , Citocinas/metabolismo , Pé Diabético/metabolismo , Glucose/metabolismo , Células Endoteliais da Veia Umbilical Humana/fisiologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neovascularização Fisiológica/fisiologia , Resultado do Tratamento
13.
Nanotechnology ; 27(32): 325303, 2016 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-27363662

RESUMO

Hierarchical assembly of plasmonic nanostructures can induce high surface-enhanced Raman scattering (SERS) activity. However, it is a challenge to uniformly disperse the hierarchical nanostructures onto a planar substrate to achieve SERS signal reproducibility. This report presents a facile route to fabricate a hexagonally patterned flower-like silver particle array as the SERS substrate. First, hexagonally ordered silver hemisphere arrays with smooth surface are molded in the pores of an anodic aluminum oxide template. Ag-nanosheets are then electrodeposited onto the surface of individual silver hemispheres. The numerous nano-edges and nano-gaps between adjacent nanosheets render a large number of hot spots, leading to high SERS activity over a larger area of chip. The silver flower-like array is employed as the SERS substrate, which is able to detect 0.1 nM rhodamine 6 G and 1 µM 3,3',4,4'-tetrachlorobiphenyl (PCB-77, a persistent organic pollutant).

14.
Nanotechnology ; 27(38): 384001, 2016 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-27528554

RESUMO

An ordered array of hierarchically-structured core-nanosphere@space-layer@shell-nanoparticles has been fabricated for surface-enhanced Raman scattering (SERS) detection. To fabricate this hierarchically-structured chip, a long-range ordered array of Au/Ag-nanospheres is first patterned in the nano-bowls on the planar surface of ordered nanoporous anodic titanium oxide template. A ultra-thin alumina middle space-layer is then conformally coated on the Au/Ag-nanospheres, and Ag-nanoparticles are finally deposited on the surface of the alumina space-layer to form an ordered array of Au/Ag-nanosphere@Al2O3-layer@Ag-nanoparticles. Finite-difference time-domain simulation shows that SERS hot spots are created between the neighboring Ag-nanoparticles. The ordered array of hierarchical nanostructures is used as the SERS-substrate for a trial detection of methyl parathion (a pesticide) in water and a limit of detection of 1 nM is reached, indicating its promising potential in rapid monitoring of organic pollutants in aquatic environment.

15.
Nanotechnology ; 25(14): 145605, 2014 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-24633265

RESUMO

Large-scale hexagonally close-packed arrays of Au-nanobowls (Au-NBs) with tens of Ag-nanoparticles (Ag-NPs) dispersed in each bowl (denoted as Ag-NPs@Au-NB arrays) are achieved and utilized as effective surface-enhanced Raman scattering (SERS) substrates. The field enhancement benefiting from the special particle-in-cavity geometrical structure as well as the high density of SERS hot spots located in the sub-10 nm gaps between adjacent Ag-NPs and at the particle-cavity junctions all together contribute to the high SERS activity of the Ag-NPs@Au-NB arrays; meanwhile the ordered morphological features of the Ag-NPs@Au-NB arrays guarantee uniformity and reproducibility of the SERS signals. By modifying the Ag-NPs@Au-NB arrays with mono-6-thio-ß-cyclodextrin, the SERS detection sensitivity to 3,3('),4,4(')-tetrachlorobiphenyl (PCB-77, one congener of polychlorinated biphenyls (PCBs, kinds of persistent organic pollutants which represent a global environmental hazard)) can be further improved and a low concentration down to 5 × 10(-7) M can still be examined, showing promising potential for application in rapid detection of trace-level PCBs in the environment.


Assuntos
Poluentes Ambientais/análise , Ouro/química , Nanoestruturas/química , Bifenilos Policlorados/análise , Prata/química , Análise Espectral Raman/métodos , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Nanopartículas , Nanoestruturas/ultraestrutura , Reprodutibilidade dos Testes , beta-Ciclodextrinas
16.
Phys Chem Chem Phys ; 16(8): 3686-92, 2014 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-24419246

RESUMO

NiO-nanoflakes (NiO-NFs) grafted Ni-nanorod (Ni-NR) arrays stuck out of the porous anodic aluminum oxide (AAO) template are achieved by a combinatorial process of AAO-confined electrodeposition of Ni-NRs, selectively etching part of the AAO template to expose the Ni-NRs, wet-etching the exposed Ni-NRs in ammonia to obtain Ni(OH)2-NFs grafted onto the cone-shaped Ni-NRs, and annealing to transform Ni(OH)2-NFs in situ into NiO-NFs. By top-view sputtering, Ag-nanoparticles (Ag-NPs) are decorated on each NiO-NFs grafted Ni-NR (denoted as NiO-NFs@Ni-NR). The resultant Ag-NPs-decorated NiO-NFs@Ni-NR (denoted as Ag-NPs@NiO-NFs@Ni-NR) arrays exhibit not only strong surface-enhanced Raman scattering (SERS) activity but also reproducible SERS-signals over the whole array. It is demonstrated that the strong SERS-activity is mainly ascribed to the high density of sub-10 nm gaps (hot spots) between the neighboring Ag-NPs, the semiconducting NiO-NFs induced chemical enhancement effect, and the lightning rod effect of the cone-shaped Ni-NRs. The three-level hierarchical nanostructure arrays stuck out of the AAO template can be utilized to probe polychlorinated biphenyls (PCBs, a kind of global environmental hazard) with a concentration as low as 5 × 10(-6) M, showing promising potential in SERS-based rapid detection of organic environmental pollutants.


Assuntos
Óxido de Alumínio/química , Nanopartículas Metálicas/química , Nanotubos/química , Níquel/química , Prata/química , Nanotubos/ultraestrutura , Bifenilos Policlorados/análise , Porosidade , Rodaminas/química , Análise Espectral Raman
17.
ACS Nano ; 18(4): 3583-3596, 2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38252681

RESUMO

The administration of drugs resident to counteract fluid washout has received considerable attention. However, the fabrication of a biocompatible system with adequate adhesion and tissue penetration capability remains challenging. This study presents a cell membrane-inspired carrier at the subcellular scale that facilitates interfacial adhesion and tissue penetration to improve drug delivery efficiency. Both chitosan oligosaccharide (COS) and oleic acid (OA) modified membranes exhibit a high affinity for interacting with the negatively charged glycosaminoglycan layer, demonstrating that the zeta potential of the carrier is the key to determining spontaneous penetration and accumulation within the bladder tissue. In vivo modeling has shown that a high surface charge significantly improves the retention of the drug carrier in the presence of urine washout. Possibly due to charge distribution, electric field gradients, and lipid membrane softening, the high positive surface charge enabled the carriers to penetrate the urinary bladder barrier and/or enter the cell interior. Overall, this study represents a practical and effective delivery strategy for tissue binders.


Assuntos
Quitosana , Lipossomos , Sistemas de Liberação de Medicamentos , Portadores de Fármacos
18.
Regen Biomater ; 11: rbad117, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38223293

RESUMO

Engineering myocardium has shown great clinal potential for repairing permanent myocardial injury. However, the lack of perfusing blood vessels and difficulties in preparing a thick-engineered myocardium result in its limited clinical use. We prepared a mixed gel containing fibrin (5 mg/ml) and collagen I (0.2 mg/ml) and verified that human umbilical vein endothelial cells (HUVECs) and human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) could form microvascular lumens and myocardial cell clusters by harnessing the low-hardness and hyperelastic characteristics of fibrin. hiPSC-CMs and HUVECs in the mixed gel formed self-organized cell clusters, which were then cultured in different media using a three-phase approach. The successfully constructed vascularized engineered myocardial tissue had a spherical structure and final diameter of 1-2 mm. The tissue exhibited autonomous beats that occurred at a frequency similar to a normal human heart rate. The internal microvascular lumen could be maintained for 6 weeks and showed good results during preliminary surface re-vascularization in vitro and vascular remodeling in vivo. In summary, we propose a simple method for constructing vascularized engineered myocardial tissue, through phased cultivation that does not rely on high-end manufacturing equipment and cutting-edge preparation techniques. The constructed tissue has potential value for clinical use after preliminary evaluation.

19.
Environ Toxicol Chem ; 43(7): 1557-1568, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38695729

RESUMO

Persistent organic pollutants pose a great threat to amphibian populations, but information on the bioaccumulation of contaminants in amphibians remains scarce. To examine the tissue distribution and maternal transfer of organic halogenated pollutants (OHPs) in frogs, seven types of tissues from black-spotted frog (muscle, liver, kidney, stomach, intestine, heart, and egg) were collected from an e-waste-polluted area in South China. Among the seven frog tissues, median total OHP concentrations of 2.3 to 9.7 µg/g lipid weight were found (in 31 polychlorinated biphenyl [PCB] individuals and 15 polybrominated diphenyl ether [PBDE], dechlorane plus [syn-DP and anti-DP], bexabromobenzene [HBB], polybrominated biphenyl] PBB153 and -209], and decabromodiphenyl ethane [DBDPE] individuals). Sex-specific differences in contaminant concentration and compound compositions were observed among the frog tissues, and eggs had a significantly higher contaminant burden on the whole body of female frogs. In addition, a significant sex difference in the concentration ratios of other tissues to the liver was observed in most tissues except for muscle. These results suggest that egg production may involve the mobilization of other maternal tissues besides muscle, which resulted in the sex-specific distribution. Different parental tissues had similar maternal transfer mechanisms; factors other than lipophilicity (e.g., molecular size and proteinophilic characteristics) could influence the maternal transfer of OHPs in frogs. Environ Toxicol Chem 2024;43:1557-1568. © 2024 SETAC.


Assuntos
Poluentes Orgânicos Persistentes , Animais , Feminino , Distribuição Tecidual , Masculino , Poluentes Orgânicos Persistentes/metabolismo , Monitoramento Ambiental , Éteres Difenil Halogenados/metabolismo , Anuros/metabolismo , China , Ranidae/metabolismo , Poluentes Químicos da Água/metabolismo , Poluentes Químicos da Água/análise
20.
Bioact Mater ; 34: 221-236, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38235307

RESUMO

Small-diameter tissue-engineered vascular grafts (sdTEVGs) have garnered significant attention as a potential treatment modality for vascular bypass grafting and replacement therapy. However, the intimal hyperplasia and thrombosis are two major complications that impair graft patency during transplantation. To address this issue, we fabricated the covalent-organic framework (COF)-based carbon monoxide (CO) nanogenerator-and co-immobilized with LXW-7 peptide and heparin to establish a multifunctional surface on TEVGs constructed from acellular blood vessels for preventing thrombosis and stenosis. The cell-adhesive peptide LXW-7 could capture endothelial-forming cells (EFCs) to promote endothelialization, while the antithrombotic molecule heparin prevented thrombus formation. The reactive oxygen species (ROS)-triggered CO release suppressed the adhesion and activation of macrophages, leading to the reduction of ROS and inflammatory factors. As a result, the endothelial-to-mesenchymal transition (EndMT) triggered by inflammation was restricted, facilitating the maintenance of the homeostasis of the neo-endothelium and preventing pathological remodeling in TEVGs. When transplanted in vivo, these vascular grafts exhibited negligible intimal hyperplasia and remained patent for 3 months. This achievement provided a novel approach for constructing antithrombotic and anti-hyperplastic TEVGs.

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