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1.
Sci Total Environ ; 753: 142050, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-32898811

RESUMO

Particulate photocatalysts developed for the solar energy-driven reduction of the greenhouse gas CO2 have a small product range and low specificity. Hybrid photosynthesis expands the number of products with photocatalysts harvesting sunlight and transferring charges to microbes harboring versatile metabolisms for bioproduction. Besides CO2, abiotic photocatalysts have been employed to increase microbial production yields of reduced compounds from organic carbon substrates. Most single-reactor hybrid photosynthesis systems comprise CdS assembled in situ by microbial activity. This approach limits optimization of the morphology, crystal structure, and crystallinity of CdS for higher performance, which is usually done via synthesis methods incompatible with life. Here, shape and activity optimized CdS nanorods were hydrothermally produced and subsequently applied to Cupriavidus necator for the heterotrophic and autotrophic production of the bioplastic polyhydroxybutyrate (PHB). C. necator with CdS NR under light produced 1.5 times more PHB when compared to the same bacterium with suboptimal commercially-available CdS. Illuminated C. necator with CdS NR synthesized 1.41 g PHB from fructose over 120 h and 28 mg PHB from CO2 over 48 h. Interestingly, the beneficial effect of CdS NR was specific to C. necator as the metabolism of other microbes often employed for bioproduction including yeast and bacteria was negatively impacted. These results demonstrate that hybrid photosynthesis is more productive when the photocatalyst characteristics are optimized via a separated synthesis process prior to being coupled with microbes. Furthermore, bioproduction improvement by CdS-based photocatalyst requires specific microbial species highlighting the importance of screening efforts for the development of performant hybrid photosynthesis.


Assuntos
Cupriavidus necator , Nanotubos , Dióxido de Carbono , Frutose , Hidroxibutiratos
2.
J Biomed Nanotechnol ; 16(6): 885-898, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33187584

RESUMO

The surface modification of titanium is effective in promoting osseointegration and is widely used in the treatment of bone diseases. Epimedii Folium (EF) plays an important role in the treatment of metabolic bone diseases. However, few studies have so far been reported on their combined use in such treatments. In the present study, EF water extract was coated onto the surface of TiO2 nanotubes (TNT) by electrochemical anodization to obtain EF-TNT. Through analysis of surface morphology characteristics, it was demonstrated that EF was successfully coated on the surface of TiO2 nanotubes. In vitro drug release data suggested that the quantity of EF water extract released was a significant quantity over 4 days, reaching a total of 80%, the release continuing in total for approximately 2 weeks. By using scanning electron microscopy and immunofluorescent staining, it was found that, EF-TNT more strongly promoted adhesion, proliferation, and differentiation of MC3T3-E1 osteoblasts compared with Ti and TNT. Quantitative reverse transcript polymerase chain reaction (qRT-PCR) analysis indicated that the expression of key genes for proliferation and differentiation of osteoblasts, such as COL1a1, ALP, OPN, and Runx2, were up-regulated by EF-TNT. Network pharmacology analysis suggested that EF water extract not only regulated the proliferation and differentiation of osteoblasts but also caused a regulatory effect on osteoclasts via multiple signaling pathways, such as RANKL-RANK-induced signaling and TGF-ß signaling. These findings indicate that the EF-TNT promotes differentiation and proliferation of osteoblasts, and represents considerable potential for use in clinical applications.


Assuntos
Nanotubos , Água , Diferenciação Celular , Proliferação de Células , Medicamentos de Ervas Chinesas , Osteoblastos , Propriedades de Superfície , Titânio/farmacologia
3.
Nat Commun ; 11(1): 4963, 2020 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-33009406

RESUMO

Bacterial nanotubes are membranous structures that have been reported to function as conduits between cells to exchange DNA, proteins, and nutrients. Here, we investigate the morphology and formation of bacterial nanotubes using Bacillus subtilis. We show that nanotube formation is associated with stress conditions, and is highly sensitive to the cells' genetic background, growth phase, and sample preparation methods. Remarkably, nanotubes appear to be extruded exclusively from dying cells, likely as a result of biophysical forces. Their emergence is extremely fast, occurring within seconds by cannibalizing the cell membrane. Subsequent experiments reveal that cell-to-cell transfer of non-conjugative plasmids depends strictly on the competence system of the cell, and not on nanotube formation. Our study thus supports the notion that bacterial nanotubes are a post mortem phenomenon involved in cell disintegration, and are unlikely to be involved in cytoplasmic content exchange between live cells.


Assuntos
Bacillus subtilis/citologia , Bacillus subtilis/metabolismo , Viabilidade Microbiana , Nanotubos/química , Bacillus subtilis/genética , Bacillus subtilis/ultraestrutura , Conjugação Genética , DNA Bacteriano/genética , Plasmídeos/genética
4.
Sensors (Basel) ; 20(20)2020 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-33080785

RESUMO

The COronaVIrus Disease (COVID-19) is a newly emerging viral disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Rapid increase in the number of COVID-19 cases worldwide led the WHO to declare a pandemic within a few months after the first case of infection. Due to the lack of a prophylactic measure to control the virus infection and spread, early diagnosis and quarantining of infected as well as the asymptomatic individuals are necessary for the containment of this pandemic. However, the current methods for SARS-CoV-2 diagnosis are expensive and time consuming, although some promising and inexpensive technologies are becoming available for emergency use. In this work, we report the synthesis of a cheap, yet highly sensitive, cobalt-functionalized TiO2 nanotubes (Co-TNTs)-based electrochemical sensor for rapid detection of SARS-CoV-2 through sensing the spike (receptor binding domain (RBD)) present on the surface of the virus. A simple, low-cost, and one-step electrochemical anodization route was used for synthesizing TNTs, followed by an incipient wetting method for cobalt functionalization of the TNTs platform, which was connected to a potentiostat for data collection. This sensor specifically detected the S-RBD protein of SARS-CoV-2 even at very low concentration (range of 14 to 1400 nM (nano molar)). Additionally, our sensor showed a linear response in the detection of viral protein over the concentration range. Thus, our Co-TNT sensor is highly effective in detecting SARS-CoV-2 S-RBD protein in approximately 30 s, which can be explored for developing a point of care diagnostics for rapid detection of SARS-CoV-2 in nasal secretions and saliva samples.


Assuntos
Betacoronavirus/metabolismo , Técnicas Biossensoriais/métodos , Nanotubos/química , Glicoproteína da Espícula de Coronavírus/análise , Titânio/química , Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/virologia , Técnicas Eletroquímicas , Humanos , Limite de Detecção , Pandemias , Pneumonia Viral/diagnóstico , Pneumonia Viral/virologia , Sistemas Automatizados de Assistência Junto ao Leito , Domínios Proteicos , Glicoproteína da Espícula de Coronavírus/química
5.
Int J Nanomedicine ; 15: 6945-6960, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33061361

RESUMO

Background: Natural clay nanomaterials are an emerging class of biomaterial with great potential for tissue engineering and regenerative medicine applications, most notably for osteogenesis. Materials and Methods: Herein, for the first time, novel tissue engineering scaffolds were prepared by 3D bioprinter using nontoxic and bioactive natural attapulgite (ATP) nanorods as starting materials, with polyvinyl alcohol as binder, and then sintered to obtain final scaffolds. The microscopic morphology and structure of ATP particles and scaffolds were observed by transmission electron microscope and scanning electron microscope. In vitro biocompatibility and osteogenesis with osteogenic precursor cell (hBMSCs) were assayed using MTT method, Live/Dead cell staining, alizarin red staining and RT-PCR. In vivo bone regeneration was evaluated with micro-CT and histology analysis in rat cranium defect model. Results: We successfully printed a novel porous nano-ATP scaffold designed with inner channels with a dimension of 500 µm and wall structures with a thickness of 330 µm. The porosity of current 3D-printed scaffolds ranges from 75% to 82% and the longitudinal compressive strength was up to 4.32±0.52 MPa. We found firstly that nano-ATP scaffolds with excellent biocompatibility for hBMSCscould upregulate the expression of osteogenesis-related genes bmp2 and runx2 and calcium deposits in vitro. Interestingly, micro-CT and histology analysis revealed abundant newly formed bone was observed along the defect margin, even above and within the 3D bioprinted porous ATP scaffolds in a rat cranial defect model. Furthermore, histology analysis demonstrated that bone was formed directly following a process similar to membranous ossification without any intermediate cartilage formation and that many newly formed blood vessels are within the pores of 3D-printed scaffolds at four and eight weeks. Conclusion: These results suggest that the 3D-printed porous nano-ATP scaffolds are promising candidates for bone tissue engineering by osteogenesis and angiogenesis.


Assuntos
Regeneração Óssea/fisiologia , Células-Tronco Mesenquimais/citologia , Engenharia Tecidual/métodos , Tecidos Suporte/química , Animais , Osso e Ossos/fisiologia , Cálcio/metabolismo , Chlorocebus aethiops , Condrogênese , Força Compressiva , Regulação da Expressão Gênica , Humanos , Compostos de Magnésio/química , Masculino , Teste de Materiais , Nanotubos/química , Osteogênese/fisiologia , Álcool de Polivinil/química , Porosidade , Impressão Tridimensional , Ratos Sprague-Dawley , Compostos de Silício/química , Células Vero , Microtomografia por Raio-X
6.
Water Res ; 186: 116380, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32919139

RESUMO

Filamentous fungi are believed to remove a wide range of environmental xenobiotics due to their characteristically non-specific catabolic metabolisms. Nonetheless, irregular hyphal spreading can lead to clogging problems in treatment facilities and the dependence of pollutant bioavailability on hyphal surface features severely limits their applicability in water treatment. Here, we propose a scalable and facile methodology to structurally modify fungal hyphae, allowing for both the maximization of pollutant sorption and fungal pellet morphology self-regulation. Halloysite-doped mycelium architectures were efficiently constructed by dipping Aspergillus fumigatus pellets in halloysite nanotube-dispersed water. Ultrastructure analyses using scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy revealed that the nanotubes were mainly attached to the outer surface of the pellets. Fungal viability and exoenzyme production were hardly affected by the halloysites. Notably, nanotube doping appeared to be extremely robust given that detachments rarely occurred even in high concentrations of organic solvents and salt. It was also demonstrated that the doped halloysites weakened hyphal growth-driven gelation, thus maintaining sphere-like pellet structures. The water treatment potential of the hybrid fungal mycelia was assessed through both cationic toxic organic/inorganic-contaminated water and real dye industry wastewater clean-ups. Aided by the mesoporous halloysite sites on their surface, the removal abilities of the hybrid structures were significantly enhanced. Moreover, inherent low sorption ability of HNT for heavy metals was found to be overcome by the aid of fungal mycelia. Finally, universal feature of the dipping-based doping way was confirmed by using different filamentous fungi. Given that traditional approaches to effectively implement fungus-based water treatment are based mostly on polymer-based immobilization techniques, our proposed approach provides a novel and effective alternative via simple doping of living fungi with environmentally-benign clays such as halloysite nanotubes.


Assuntos
Nanotubos , Purificação da Água , Cerâmica , Argila , Hifas
7.
Water Res ; 186: 116327, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32846377

RESUMO

The presence of contaminants of emerging concern (CECs) in various water bodies and the associated threats to eco-system and human society have raised increasing concerns. To fight against such a problem, TiO2 photocatalysis is considered to be a powerful tool. In recent decades, TiO2 nanotube array (TNA) fabricated by electrochemical anodization emerged as a viable immobilized catalyst and its applications on CECs removal have gained a considerable amount of research interest. We herein present a critical review on the development of TNA and its applications on the removal of aqueous CECs. In this work, the CECs removal in different TNA based processes, the CECs removal mechanisms, the role of TNA properties, the role of operational parameters, and the role of water matrices are discussed. Moreover, perspectives on the current research progress are presented and recommendations on future research are elaborated.


Assuntos
Nanotubos , Catálise , Humanos , Titânio , Águas Residuárias
8.
Chemosphere ; 261: 127778, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32739692

RESUMO

Vibration is one of the most prevalent energy sources in natural environment, which can also be harvested and utilized to drive chemical reaction. Herein, mechanical vibration is used for enhancing the catalytic decomposition of formaldehyde at ambient temperature with the assistance of four well-defined morphologies α-MnO2 (nanowire, nanotube, nanorod and nanoflower). In particular, α-MnO2 nanowire exhibits the best catalytic activity, which can completely mineralize formaldehyde into carbon dioxide at ambient temperature by harvesting the vibration energy. To the best of our knowledge, this may be the first report that α-MnO2, as a non-noble metal catalyst, can completely decompose formaldehyde to carbon dioxide at ambient temperature. The characterization results show that α-MnO2 nanowire has a much higher oxygen vacancy concentration than other three catalysts. In addition, thermal effect generated from friction between nanoparticles induced by ultrasonic vibration may enhance its catalytic activity. More importantly, it is the vibration that effectively promotes the activation of O2 adsorbed on the surface oxygen vacancy to produce more , thus increasing the catalytic decomposition performance. The strategy presented herein demonstrates a new approach for efficient use of mechanical vibration to improve catalytic activity of traditional catalysts.


Assuntos
Poluentes Atmosféricos/química , Formaldeído/química , Compostos de Manganês/química , Nanoestruturas/química , Adsorção , Carcinógenos , Catálise , Nanopartículas , Nanotubos/química , Nanofios , Oxirredução , Óxidos/química , Oxigênio/química , Temperatura , Vibração
9.
J Environ Manage ; 271: 111019, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32778301

RESUMO

Kaolinite nanotubes were synthesized by a simple scrolling process and decorated by ZnO nanoparticles as a novel nanocomposite (ZnO/KNTs). The synthetic ZnO/KNTs composite was characterized as an effective photocatalyst in the oxidation of levofloxacin pharmaceutical residuals in the water resources. The composite displays a surface area of 95.4 m2/g, average pore diameter of 5.8 nm, and bandgap energy of 2.12 eV. It is of high catalytic activity in the oxidation of levofloxacin in the presence of visible light source. The complete oxidation for 10 mg/L of levofloxacin was recognized after 55 min, 45 min, and 30 min with applying 30 mg, 40 mg, and 50 mg of ZnO/KNTs as catalyst dosage, respectively. Additionally, it achieved complete oxidation for 20 mg/L and 30 mg/L of levofloxacin after 45 min and 75 min, respectively using 50 mg as catalyst dosage. The degradation efficiency was confirmed by detecting the residual TOC after the treatment tests and the formed intermediate compounds were identified to suggest the degradation pathways. In addition to the oxidation pathway, the mechanism was evaluated based on the active trapping tests that proved the dominance of hydroxyl radicals as the essential active species. Finally, the ZnO/KNTs composite is of promising recyclability properties and achieved better results than several studied photocatalysts in literature.


Assuntos
Nanotubos , Preparações Farmacêuticas , Óxido de Zinco , Argila , Levofloxacino , Luz , Água
10.
Nature ; 585(7823): 91-95, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32788726

RESUMO

Signalling between cells of the neurovascular unit, or neurovascular coupling, is essential to match local blood flow with neuronal activity. Pericytes interact with endothelial cells and extend processes that wrap capillaries, covering up to 90% of their surface area1,2. Pericytes are candidates to regulate microcirculatory blood flow because they are strategically positioned along capillaries, contain contractile proteins and respond rapidly to neuronal stimulation3,4, but whether they synchronize microvascular dynamics and neurovascular coupling within a capillary network was unknown. Here we identify nanotube-like processes that connect two bona fide pericytes on separate capillary systems, forming a functional network in the mouse retina, which we named interpericyte tunnelling nanotubes (IP-TNTs). We provide evidence that these (i) have an open-ended proximal side and a closed-ended terminal (end-foot) that connects with distal pericyte processes via gap junctions, (ii) carry organelles including mitochondria, which can travel along these processes, and (iii) serve as a conduit for intercellular Ca2+ waves, thus mediating communication between pericytes. Using two-photon microscope live imaging, we demonstrate that retinal pericytes rely on IP-TNTs to control local neurovascular coupling and coordinate light-evoked responses between adjacent capillaries. IP-TNT damage following ablation or ischaemia disrupts intercellular Ca2+ waves, impairing blood flow regulation and neurovascular coupling. Notably, pharmacological blockade of Ca2+ influx preserves IP-TNTs, rescues light-evoked capillary responses and restores blood flow after reperfusion. Our study thus defines IP-TNTs and characterizes their critical role in regulating neurovascular coupling in the living retina under both physiological and pathological conditions.


Assuntos
Nanotubos , Acoplamento Neurovascular , Pericitos/metabolismo , Animais , Isquemia Encefálica/metabolismo , Isquemia Encefálica/patologia , Cálcio/metabolismo , Sinalização do Cálcio , Capilares/fisiopatologia , Capilares/efeitos da radiação , Comunicação Celular , Feminino , Junções Comunicantes/metabolismo , Hemodinâmica , Masculino , Camundongos , Mitocôndrias/metabolismo , Acoplamento Neurovascular/fisiologia , Pericitos/citologia , Pericitos/patologia , Retina/citologia , Retina/patologia
11.
12.
J Contemp Dent Pract ; 21(5): 475-480, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32690826

RESUMO

AIM: Gold nanorods (GNRs) have gained interest as a promising carrier for antibiotics. Gold nanorods may reduce the development of antimicrobial resistance in certain microbial species. Although applications of GNRs to mitigate oral biofilms are under development, their use in the oral cavity may have adverse effects. The aim of this study was to evaluate the potential penetration of GNRs into the tooth enamel structure using confocal laser scanning microscopy (CLSM) and scanning transmission electron microscopy (STEM). MATERIALS AND METHODS: Our approach was to synthesize GNRs with cationic [cetyltrimethylammoniumbromide (CTAB)] and anionic [11-mercaptoundecanoic acid (MUDA)] surface coatings. We hypothesized that penetration would be surface coating dependent. RESULTS: Regardless of the chemical modification of the GNRs of size ∼20 nm × 8 nm, exposure of these materials did not result in superficial penetration into the enamel. CONCLUSION: Within the limitations of this study, it is concluded that the use of CLSM and STEM is a feasible approach to investigate the penetration of nanomaterials into the tooth structure. CLINICAL SIGNIFICANCE: Exposure of the enamel with chemically modified GNRs of size ∼20 nm × 8 nm will not result in superficial penetration into the enamel.


Assuntos
Ouro , Nanotubos , Cetrimônio , Compostos de Cetrimônio , Esmalte Dentário
13.
J Adhes Dent ; 22(4): 399-407, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32666066

RESUMO

PURPOSE: The aim of this study was to evaluate the chemomechanical properties, antibacterial activity, and cytotoxicity of an experimental adhesive resin containing halloysite nanotubes (HNT), doped with alkyl trimethyl ammonium bromide (ATAB). MATERIALS AND METHODS: A filler of HNT doped with ATAB was obtained (ATAB:HNT) and incorporated (5 wt%) into a resin blend made of bisphenol A glycerolate dimethacrylate, 2-hydroxyethyl methacrylate and a photoinitiator/co-initiator system (GATAB:HNT). The same resin blend without ATAB:HNT was used as control (Ctrl). The ATAB:HNT filler was assessed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The two tested adhesives were evaluated for degree of conversion (DC) in vitro and in situ, softening in alcohol, dentin microtensile bond strength (µTBS), antibacterial activity, and cytotoxicity (n = 5). RESULTS: SEM showed that the nanotubes had a characteristic tubular-needle morphology, while the TEM analysis confirmed the presence of ATAB inside the lumens of HNT. The incorporation of ATAB:HNT induced no reduction (p > 0.05) of the DC either in situ or in vitro. No difference was encountered after the softening challenge test (p > 0.05) and no difference was found in µTBS between the two adhesives, both at 24 h (p > 0.05) and after 6 months of storage in distilled water (p > 0.05). However, ATAB:HNT reduced Streptococcus mutans viability (p < 0.05) without a cytotoxic effect on pulp cells (p > 0.05). CONCLUSIONS: GATAB:HNT adhesive demonstrated appropriate polymerization without significant differences in softening after solvent immersion, while concomitantly maintaining reliable bond strength after 6 months of water aging. Moreover, the ATAB:HNT filler can provide antibacterial activity to the adhesive resin without affecting pulp cell viability.


Assuntos
Colagem Dentária , Nanotubos , Brometos , Argila , Cimentos Dentários , Dentina , Adesivos Dentinários , Teste de Materiais , Microscopia Eletrônica de Varredura , Compostos de Amônio Quaternário , Cimentos de Resina , Resistência à Tração
14.
Int J Nanomedicine ; 15: 4151-4169, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32606670

RESUMO

Purpose: Focused ultrasound (FUS) is a noninvasive method to produce thermal and mechanical destruction along with an immune-stimulatory effect against cancer. However, FUS ablation alone appears insufficient to generate consistent antitumor immunity. In this study, a multifunctional nanoparticle was designed to boost FUS-induced immune effects and achieve systemic, long-lasting antitumor immunity, along with imaging and thermal enhancement. Materials and Methods: PEGylated PLGA nanoparticles encapsulating astragalus polysaccharides (APS) and gold nanorods (AuNRs) were constructed by a simple double emulsion method, characterized, and tested for cytotoxicity. The abilities of PA imaging and thermal-synergetic ablation efficiency were analyzed in vitro and in vivo. The immune-synergistic effect on dendritic cell (DC) differentiation in vitro and the immune response in vivo were also evaluated. Results: The obtained APS/AuNR/PLGA-PEG nanoparticles have an average diameter of 255.00±0.1717 nm and an APS-loading efficiency of 54.89±2.07%, demonstrating their PA imaging capability and high biocompatibility both in vitro and in vivo. In addition, the as-prepared nanoparticles achieved a higher necrosis cell rate and induced apoptosis rate in an in vitro cell suspension assay, greater necrosis area and decreased energy efficiency factor (EEF) in an in vivo rabbit liver assay, and remarkable thermal-synergic performance. In particular, the nanoparticles upregulated the expression of MHC-II, CD80 and CD86 on cocultured DCs in vitro, followed by declining phagocytic function and enhanced interleukin (IL)-12 and interferon (INF)-γ production. Furthermore, they boosted the production of tumor necrosis factor (TNF)-α, IFN-γ, IL-4, IL-10, and IgG1 (P< 0.001) but not IgG2a. Immune promotion peaked on day 3 after FUS in vivo. Conclusion: The multifunctional APS/AuNR/PLGA-PEG nanoparticles can serve as an excellent synergistic agent for FUS therapy, facilitating real-time imaging, promoting thermal ablation effects, and boosting FUS-induced immune effects, which have the potential to be used for further clinical FUS treatment.


Assuntos
Astrágalo (Planta)/química , Neoplasias da Mama/terapia , Ouro/química , Nanopartículas Multifuncionais/química , Nanotubos/química , Polissacarídeos/química , Terapia por Ultrassom , Animais , Antígenos CD/metabolismo , Apoptose , Morte Celular , Diferenciação Celular , Linhagem Celular Tumoral , Proliferação de Células , Citocinas/metabolismo , Células Dendríticas/citologia , Feminino , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Imunoglobulina G/metabolismo , Linfócitos do Interstício Tumoral/imunologia , Camundongos Endogâmicos BALB C , Fagocitose , Técnicas Fotoacústicas , Poliésteres/síntese química , Poliésteres/química , Polietilenoglicóis/síntese química , Polietilenoglicóis/química , Coelhos , Nanomedicina Teranóstica , Fator A de Crescimento do Endotélio Vascular/metabolismo
15.
Int J Nanomedicine ; 15: 4171-4189, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32606671

RESUMO

Background: Angiogenic and osteogenic activities are two major problems with biomedical titanium (Ti) and other orthopedic implants used to repair large bone defects. Purpose: The aim of this study is to prepare hydroxyapatite (HA) coatings on the surface of Ti by using electrochemical deposition (ED), and to evaluate the effects of nanotopography and silicon (Si) doping on the angiogenic and osteogenic activities of the coating in vitro. Materials and Methods: HA coating and Si-doped HA (HS) coatings with varying nanotopographies were fabricated using two ED modes, ie, the pulsive current (PC) and cyclic voltammetry (CV) methods. The coatings were characterized through scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectrometer (XPS), and atomic force microscopy (AFM), and their in vitro bioactivity and protein adsorption were assessed. Using MC3T3-E1 pre-osteoblasts and HUVECs as cell models, the osteogenic and angiogenic capabilities of the coatings were evaluated through in vitro cellular experiments. Results: By controlling Si content in ~0.8 wt.%, the coatings resulting from the PC mode (HA-PC and HS-PC) and CV mode (HA-CV and HS-CV) had nanosheet and nanorod topographies, respectively. At lower crystallinity, higher ionic dissolution, smaller contact angle, higher surface roughness, and more negative zeta potential, the HS and PC samples exhibited quicker apatite deposition and higher BSA adsorption capacity. The in vitro cell study showed that Si doping was more favorable for enhancing the viability of the MC3T3-E1 cells, but nanosheet coating increased the area for cell spreading. Of the four coatings, HS-PC with Si doping and nanosheet topography exhibited the best effect in terms of up-regulating the expressions of the osteogenic genes (ALP, Col-I, OSX, OPN and OCN) in the MC3T3-E1 cells. Moreover, all leach liquors of the surface-coated Ti disks promoted the growth of the HUVECs, and the HS samples played a more significant role in promoting cell migration and tube formation than the HA samples. Of the four leach liquors, only the two HS samples up-regulated NO content and expressions of the angiogenesis-related genes (VEGF, bFGF and eNOS) in the HUVECs, and the HS-PC yielded a better effect. Conclusion: The results show that Si doping while regulating the topography of the coating can help enhance the bone regeneration and vascularization of HA-coated Ti implants.


Assuntos
Materiais Revestidos Biocompatíveis/farmacologia , Durapatita/farmacologia , Nanopartículas/química , Osteogênese , Próteses e Implantes , Silício/química , Titânio/farmacologia , Adsorção , Animais , Linhagem Celular , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Camundongos , Nanopartículas/ultraestrutura , Nanotubos/química , Neovascularização Fisiológica/efeitos dos fármacos , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Osteogênese/genética , Soroalbumina Bovina/química , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Difração de Raios X
16.
Int J Nanomedicine ; 15: 4471-4481, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32606689

RESUMO

Background: Ineffective integration has been recognized as one of the major causes of early orthopedic failure of titanium-based implants. One strategy to address this problem is to develop modified titanium surfaces that promote osteoblast differentiation. This study explored titanium surfaces modified with TiO2 nanotubes (TiO2 NTs) capable of localized drug delivery into bone and enhanced osteoblast cell differentiation. Materials and Methods: Briefly, TiO2 NTs were subjected to anodic oxidation and loaded with Metformin, a widely used diabetes drug. To create surfaces with sustainable drug-eluting characteristics, TiO2 NTs were spin coated with a thin layer of chitosan. The surfaces were characterized via scanning electron microscopy, atomic force microscopy, and contact angle measurements. The surfaces were then exposed to mesenchymal bone marrow stem cells (MSCs) to evaluate cell adhesion, growth, differentiation, and morphology on the modified surfaces. Results: A noticeable increase in drug release time (3 days vs 20 days) and a decrease in burst release characteristics (85% to 7%) was observed in coated samples as compared to uncoated samples, respectively. Chitosan-coated TiO2 NTs exhibited a considerable enhancement in cell adhesion, proliferation, and genetic expression of type I collagen, and alkaline phosphatase activity as compared to uncoated TiO2 NTs. Conclusion: TiO2 NT surfaces with a chitosan coating are capable of delivering Metformin to a bone site over a sustained period of time with the potential to enhance MSCs cell attachment, proliferation, and differentiation.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Quitosana/química , Liberação Controlada de Fármacos , Metformina/farmacologia , Nanotubos/química , Osteoblastos/citologia , Titânio/química , Fosfatase Alcalina/metabolismo , Animais , Adesão Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Humanos , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Nanotubos/ultraestrutura , Osteoblastos/efeitos dos fármacos , Osteoblastos/ultraestrutura , Osteogênese/efeitos dos fármacos , Ratos Wistar , Molhabilidade
17.
Life Sci ; 257: 118108, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32682920

RESUMO

AIM: Preparation of pegylated gold nanorods (PEG-AuNRs) that are capable of converting near infrared (NIR) light into heat. Evaluation of cancer therapeutic efficacy and long-term toxicity of the proposed photothermal therapy in comparison with other conventional modalities. MATERIALS AND METHODS: Prepared PEG-AuNRs were characterized by measuring their absorption spectra, zeta potential, and transmission electron microscope (TEM). Cancer therapeutic efficacy was assessed by monitoring tumor growth, measuring DNA damage and superoxide dismutase (SOD) and malondialdehyde (MDA) levels in addition to examining tumor histopathology. Further analysis concerning the toxicity of all the proposed treatment modalities was also assessed by evaluating the cytotoxicity and genotoxicity in liver and kidney tissues. KEY FINDINGS: The results demonstrated that both photothermal therapy (PEG-AuNRs + NIR laser) and chemotherapy (cisplatin) have higher efficacy in diminishing Ehrlich tumor growth with significance DNA damage over the other treatment modalities. Concerning the biosafety issue, mice treated photothermally exhibited lower MDA level and higher SOD activity in liver and kidney tissues compared with other treated groups. DNA damage represented by tail moment and olive moment of kidney tissues exhibited lower values for photothermal treated group and higher values for cisplatin treated group. SIGNIFICANCE: Photothermal therapy (PEG-AuNRs + NIR laser) potentiates higher efficacy in treating Ehrlich tumor with minimum toxicity in comparison with other conventional treatment modalities.


Assuntos
Carcinoma de Ehrlich/terapia , Ouro/administração & dosagem , Nanotubos/toxicidade , Fototerapia/métodos , Animais , Carcinoma de Ehrlich/patologia , Ensaio Cometa , Dano ao DNA/efeitos dos fármacos , Feminino , Ouro/uso terapêutico , Ouro/toxicidade , Malondialdeído/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Eletrônica de Transmissão , Nanotubos/ultraestrutura , Transplante de Neoplasias , Estresse Oxidativo , Superóxido Dismutase/metabolismo
18.
J Appl Oral Sci ; 28: e20190771, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32609187

RESUMO

OBJECTIVE: Titanium dioxide nanotubes are nanostructures that can accelerate the oxidation reaction of bleaching procedures and promote a more effective whitening effect. This study evaluated physicochemical properties of bleaching agents incorporated with titanium dioxide (TiO2) nanotubes, and the effects on tooth color change at different periods. METHODOLOGY: 40 premolars were treated according to the following groups (n=10): CP - 10% carbamide peroxide (1 hour daily/21 days); CPN - CP incorporated into TiO2; HP - 40% hydrogen peroxide (three 40-minute sessions/7 days apart); HPN - HP incorporated into TiO2. Color shade was evaluated at five different periods (baseline, after 7, 14 and 21 days of bleaching, and 7 days after end of treatment) according to Vita Classical, CIELab and CIEDE2000 scales. Mean particle size (P), polydispersity (PO) and zeta potential (ZP) were evaluated using dynamic light scattering. Data on the different variables were analyzed by mixed model tests for measures repeated in time (ZP e L*), generalized linear models for measures repeated in time (P, PO, Vita Classical and b*), and Friedman and Mann-Whitney tests (a* and color change/ΔE and ΔE00). RESULTS: CP and CPN presented higher P, higher PO and lower ZP than HP and HPN (p≤0.05). All groups showed a significant decrease in Vita Classical color scores after 7 days of bleaching (p<0.05), and HPN presented a greater significant reduction than the other groups. L* increased in TiO2 presence, in all groups, without any differences (p>0.05) in bleaching time. A significant reduction occurred in the a* and b* values for all the groups, and HPN presented lower a* and b* values (p<0.05) than CPN. ΔE was clinically noticeable after 7 days, in all groups, and all groups resulted in a perceptible color change according to ΔE00. CONCLUSION: TiO2 did not influence physicochemical properties of the bleaching agents. HPN presented more effective tooth bleaching than CPN.


Assuntos
Clareadores , Nanotubos , Clareadores Dentários , Clareamento Dental , Cor , Esmalte Dentário , Peróxido de Hidrogênio , Peróxidos , Titânio , Ureia
19.
Chemosphere ; 261: 127731, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32731023

RESUMO

Well-aligned ZnO nanorod arrays were assembled on activated carbon fibers by a stepwise sequence of sol-gel and hydrothermal synthesis methods. These ZnO nanorod arrays on activated carbon fibers having different characteristics such as surface area, rod concentration, aspect ratio and defect level, were applied as catalysts for the photodegradation of an aqueous methylene blue solution. They showed very promising methylene blue adsorbility in the dark (ca. 0.025-0.031 mg methylene blue m-2 catalyst, vs. 0.072 mg methylene blue m-2 activated carbon fibers). Significantly, the defect level of ZnO nanorod arrays has a major effect on the turnover frequency compared to other characteristics. A synergistic effect between activated carbon fibers and ZnO nanocrystals on enhancing turnover frequency was more significant for the well-assembled ZnO nanorod arrays on activated carbon fibers catalysts compared to the mechanically mixed ZnO powder with activated carbon fibers catalyst. Further, turnover frequency for the ZnO nanorod arrays on activated carbon fibers (0.00312 molmethylene blue molZnO-1 h-1) was twice higher than that for the corresponding bare ZnO nanorod arrays, and 3 times higher than that for a commercial ZnO powder. In addition, ZnO nanorod arrays on activated carbon fibers show high degradation (77.5%) and mineralization (55.0%) levels for methylene blue, and also good reusability (or stability) as demonstrated by a sequential 5-time recycle routine. These outstanding features indicate that activated carbon fibers supported ZnO nanorod arrays have significant potential to be used as catalysts for photodegradation.


Assuntos
Fibra de Carbono/química , Carvão Vegetal/química , Azul de Metileno/análise , Nanotubos/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Óxido de Zinco/química , Catálise , Azul de Metileno/química , Modelos Teóricos , Nanopartículas/química , Fotólise , Propriedades de Superfície , Raios Ultravioleta
20.
Science ; 368(6495): 1108-1113, 2020 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-32499439

RESUMO

Enabling near-infrared light sensitivity in a blind human retina may supplement or restore visual function in patients with regional retinal degeneration. We induced near-infrared light sensitivity using gold nanorods bound to temperature-sensitive engineered transient receptor potential (TRP) channels. We expressed mammalian or snake TRP channels in light-insensitive retinal cones in a mouse model of retinal degeneration. Near-infrared stimulation increased activity in cones, ganglion cell layer neurons, and cortical neurons, and enabled mice to perform a learned light-driven behavior. We tuned responses to different wavelengths, by using nanorods of different lengths, and to different radiant powers, by using engineered channels with different temperature thresholds. We targeted TRP channels to human retinas, which allowed the postmortem activation of different cell types by near-infrared light.


Assuntos
Cegueira/terapia , Ouro , Raios Infravermelhos , Nanotubos , Degeneração Retiniana/terapia , Limiar Sensorial/efeitos da radiação , Canais de Cátion TRPC/fisiologia , Visão Ocular/efeitos da radiação , Animais , Cegueira/fisiopatologia , Modelos Animais de Doenças , Potenciais Evocados Visuais/fisiologia , Potenciais Evocados Visuais/efeitos da radiação , Engenharia Genética , Células HEK293 , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Estimulação Luminosa , Ratos , Células Fotorreceptoras Retinianas Cones/fisiologia , Células Fotorreceptoras Retinianas Cones/efeitos da radiação , Degeneração Retiniana/fisiopatologia , Células Ganglionares da Retina/fisiologia , Células Ganglionares da Retina/efeitos da radiação , Limiar Sensorial/fisiologia , Serpentes , Canais de Cátion TRPC/genética , Canais de Cátion TRPV/genética , Canais de Cátion TRPV/fisiologia , Visão Ocular/fisiologia , Córtex Visual/fisiopatologia , Córtex Visual/efeitos da radiação
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