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1.
Nat Commun ; 11(1): 1861, 2020 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-32313096

RESUMO

Memristive devices are promising candidates to emulate biological computing. However, the typical switching voltages (0.2-2 V) in previously described devices are much higher than the amplitude in biological counterparts. Here we demonstrate a type of diffusive memristor, fabricated from the protein nanowires harvested from the bacterium Geobacter sulfurreducens, that functions at the biological voltages of 40-100 mV. Memristive function at biological voltages is possible because the protein nanowires catalyze metallization. Artificial neurons built from these memristors not only function at biological action potentials (e.g., 100 mV, 1 ms) but also exhibit temporal integration close to that in biological neurons. The potential of using the memristor to directly process biosensing signals is also demonstrated.


Assuntos
Potenciais de Ação , Eletrônica/instrumentação , Geobacter/metabolismo , Nanofios/química , Neurônios , Técnicas Biossensoriais , Eletricidade , Desenho de Equipamento , Humanos , Simulação de Dinâmica Molecular , Nanotecnologia/instrumentação , Nanofios/ultraestrutura , Redes Neurais de Computação , Sinapses/metabolismo , Dispositivos Eletrônicos Vestíveis
2.
Sci Adv ; 6(7): eaay2760, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32110728

RESUMO

Bacterial response to transient physical stress is critical to their homeostasis and survival in the dynamic natural environment. Because of the lack of biophysical tools capable of delivering precise and localized physical perturbations to a bacterial community, the underlying mechanism of microbial signal transduction has remained unexplored. Here, we developed multiscale and structured silicon (Si) materials as nongenetic optical transducers capable of modulating the activities of both single bacterial cells and biofilms at high spatiotemporal resolution. Upon optical stimulation, we capture a previously unidentified form of rapid, photothermal gradient-dependent, intercellular calcium signaling within the biofilm. We also found an unexpected coupling between calcium dynamics and biofilm mechanics, which could be of importance for biofilm resistance. Our results suggest that functional integration of Si materials and bacteria, and associated control of signal transduction, may lead to hybrid living matter toward future synthetic biology and adaptable materials.


Assuntos
Bactérias/metabolismo , Transdução de Sinais , Silício/química , Bactérias/ultraestrutura , Biofilmes , Sinalização do Cálcio , Nanofios/ultraestrutura
3.
Mater Sci Eng C Mater Biol Appl ; 108: 110371, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31924004

RESUMO

The objective of this paper is to demonstrate the potential of nanostructured polypyrrole formed by template free as platform for amperometric detection of DNA. The nanowires of polypyrrole (nw-PPy) are formed through electrochemical polymerization and chemically modified by electrochemical oxidation of ethylene diamine or dendrimers PAMAM to obtain aminated surface. The DNA probe and ferrocenyl group, as redox reporter, were covalently linked to the surface of nw-PPy. The chemical structure of nanostructured platform was characterized through SEM, FT-IR and XPS and the electrochemical properties through cyclic voltammetry and electrochemical impedance spectroscopy (EIS). We show that the properties of nw-PPy such as, hydrophilic character and large surface area have large effect on the electronic properties. Thus, the electrochemical performance is increased compared to others nanomaterials considering the obtained value of the rate of electron transfer of 18 s-1. These properties allow enhanced DNA sensing where detection limit of 0.36 atomolar without any amplification step. The biosensor can be applied in detection of genomic DNA of Mycobacterium tuberculosis and the mutated one which present the resistance to rifampicin and large selectivity was demonstrated. We believe that nw-PPy modified with redox marker is a promising platform for electrochemical biosensors and can be applied for various diagnosis prospects.


Assuntos
Técnicas Biossensoriais , DNA Bacteriano/análise , Técnicas Eletroquímicas/métodos , Mycobacterium tuberculosis/genética , Nanoestruturas/química , Polímeros/química , Pirróis/química , Dendrímeros/química , Eletrólitos/química , Compostos Ferrosos/química , Ouro/química , Cinética , Metalocenos/química , Mycobacterium tuberculosis/isolamento & purificação , Nanoestruturas/ultraestrutura , Nanofios/química , Nanofios/ultraestrutura , Espectroscopia Fotoeletrônica , Espectroscopia de Infravermelho com Transformada de Fourier
4.
Nano Lett ; 19(9): 6569-6576, 2019 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-31381357

RESUMO

Reports reveal that the piezoresistance coefficients of silicon carbide (SiC) nanowires (NWs) are 2 to 4 times smaller than those of their corresponding bulk counterparts. It is a challenge to eliminate contamination in adhering NWs onto substrates. In this study, a new setup was developed, in which NWs were manipulated and fixed by a goat hair and conductive silver epoxy in air, respectively, in the absence of any depositions. The goat hair was not consumed during manipulation of the NWs. The process took advantage of the stiffness and tapered tip of the goat hair, which is unlike the loss issue of beam sources in depositions. With the new fixing method, in situ transmission electron microscopy (TEM) electromechanical coupling measurements were performed on pristine SiC NWs. The piezoresistance coefficient and carrier mobility of SiC NW are -94.78 × 10-11 Pa-1 and 30.05 cm2 V-1 s-1, respectively, which are 82 and 527 times respectively greater than those of SiC NWs reported previously. We, for the first time, report that the piezoresistance coefficient of SiC NW is 17 times those of its bulk counterparts. These findings provide new insights to develop high performance SiC devices and to help avoid catastrophic failure when working in harsh environments.


Assuntos
Compostos Inorgânicos de Carbono/química , Cabelo/química , Nanofios/química , Compostos de Silício/química , Prata/química , Estresse Mecânico , Animais , Cabras , Microscopia Eletrônica de Transmissão , Nanofios/ultraestrutura
5.
Biosens Bioelectron ; 142: 111527, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31344601

RESUMO

In this work, a modification procedure for the functionalization of silicon nanowire (SiNW) is applied in biological field effect transistor (BioFET) system. The proposed method precedes the silanization reaction in a manner that the only SiNW and not its SiO2 substrate is functionalized by (3-Aminopropyl) triethoxysilane (APTES) initiators. This method has an effective role in increasing the sensitivity of BioFET sensors and can be applied in commercial ones. Furthermore, we introduce an efficient computational technique to estimate unknown senor parameters. To that end, Bayesian inversion is used to determine the number of PSA target molecules bound to the receptors in both selective and nonselective SiNWs. The approach is coupled with the Poisson-Boltzmann-drift-diffusion (PBDD) equations to provide a comprehensive system to model all biosensor interactions.


Assuntos
Anticorpos Imobilizados/química , Técnicas Biossensoriais/métodos , Nanofios/química , Antígeno Prostático Específico/sangue , Silício/química , Algoritmos , Teorema de Bayes , Técnicas Biossensoriais/instrumentação , Desenho de Equipamento , Humanos , Nanotecnologia/métodos , Nanofios/ultraestrutura , Propilaminas/química , Antígeno Prostático Específico/análise , Silanos/química
6.
Nat Nanotechnol ; 14(8): 783-790, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31263191

RESUMO

New tools for intracellular electrophysiology that push the limits of spatiotemporal resolution while reducing invasiveness could provide a deeper understanding of electrogenic cells and their networks in tissues, and push progress towards human-machine interfaces. Although significant advances have been made in developing nanodevices for intracellular probes, current approaches exhibit a trade-off between device scalability and recording amplitude. We address this challenge by combining deterministic shape-controlled nanowire transfer with spatially defined semiconductor-to-metal transformation to realize scalable nanowire field-effect transistor probe arrays with controllable tip geometry and sensor size, which enable recording of up to 100 mV intracellular action potentials from primary neurons. Systematic studies on neurons and cardiomyocytes show that controlling device curvature and sensor size is critical for achieving high-amplitude intracellular recordings. In addition, this device design allows for multiplexed recording from single cells and cell networks and could enable future investigations of dynamics in the brain and other tissues.


Assuntos
Eletrofisiologia/instrumentação , Nanofios/química , Transistores Eletrônicos , Potenciais de Ação , Animais , Células Cultivadas , Desenho de Equipamento , Humanos , Miócitos Cardíacos/metabolismo , Nanofios/ultraestrutura , Neurônios/metabolismo
7.
Molecules ; 24(12)2019 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-31238523

RESUMO

Copper nanowires (Cu NWs) were modified with graphene oxide (GO) nanosheets to obtain a sensor for simultaneous voltammetric determination of ascorbic acid (AA), dopamine (DA) and acetaminophen (AC). The nanocomposite was obtained via sonication, and its structures were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS). The electrochemical oxidation activity of the materials (placed on a glassy carbon electrode) was studied by cyclic voltammetry and differential pulse voltammetry. Due to the synergistic effect of Cu NWs and GO, the specific surface, electrochemical oxidation performance and conductivity are improved when compared to each individual component. The peaks for AA (-0.08 V), DA (+0.16 V), and AC (+0.38 V) are well separated. The sensor has wide linear ranges which are from 1-60 µM, 1-100 µM, and 1-100 µM for AA, DA, and AC, respectively, when operated in the differential pulse voltammetric mode. The detection limits are 50, 410 and 40 nM, respectively. Potential interferences by uric acid (20 µM), glucose (10 mM), NaCl (1 mM), and KCl (1 mM) were tested for AA (1 µΜ), DA (1 µΜ), and AC (1 µΜ) and were found to be insignificant. The method was successfully applied to the quantification of AA, DA, and AC in spiked serum samples.


Assuntos
Cobre/química , Técnicas Eletroquímicas , Grafite/química , Nanoestruturas/química , Nanofios/química , Acetaminofen/sangue , Acetaminofen/metabolismo , Ácido Ascórbico/sangue , Ácido Ascórbico/metabolismo , Técnicas Biossensoriais , Dopamina/sangue , Dopamina/metabolismo , Humanos , Nanoestruturas/ultraestrutura , Nanofios/ultraestrutura , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
8.
PLoS One ; 14(6): e0218122, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31226121

RESUMO

Semiconductor nanowires are increasingly used in optoelectronic devices. However, their effects on human health have not been assessed fully. Here, we investigate the effects of gallium phosphide nanowires on human lung adenocarcinoma cells. Four different geometries of nanowires were suspended in the cell culture for 48 hours. We show that cells internalize the nanowires and that the nanowires have no effect on cell proliferation rate, motility, viability and intracellular ROS levels. By blocking specific internalization pathways, we demonstrate that the nanowire uptake is the result of a combination of processes, requiring dynamin and actin polymerization, which suggests an internalization through macropinocytosis and phagocytosis.


Assuntos
Adenocarcinoma de Pulmão/metabolismo , Nanofios/química , Células A549 , Adenocarcinoma de Pulmão/patologia , Contagem de Células , Morte Celular , Forma do Núcleo Celular , Proliferação de Células , Sobrevivência Celular , Endocitose , Humanos , Nanofios/ultraestrutura , Espécies Reativas de Oxigênio/metabolismo
9.
Nano Lett ; 19(6): 3569-3574, 2019 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-31117749

RESUMO

A novel method to fabricate porous Fe-Ni-Co nanowires directly by electrodepositing into polycarbonate membranes is reported when the electrolyte pH < 0.5. Hydrogen bubbles are used as a dynamic porous template created by operating in electrolytes with very low pH to drive the proton reduction reaction. The electrolyte pH was adjusted with sulfuric acid, and the added sulfate ions are thought to help reduce bubble coalescence, but not detachment at the electrode surface, to facilitate metal deposition within the nanopores. Porous nanowires were obtained when the electrolyte pH was less than 1.0. The average alloy composition was found to be pH sensitive, which shifted from an Fe-rich porous alloy to a Ni-rich porous alloy as the electrolyte pH decreased.


Assuntos
Cobalto/química , Ferro/química , Nanofios/química , Níquel/química , Ligas/química , Galvanoplastia/métodos , Hidrogênio/química , Nanotecnologia/métodos , Nanofios/ultraestrutura , Cimento de Policarboxilato/química , Porosidade
10.
Int J Nanomedicine ; 14: 3155-3176, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31118629

RESUMO

Background: Traditional physicochemical approaches for the synthesis of compounds, drugs, and nanostructures developed as potential solutions for antimicrobial resistance or against cancer treatment are, for the most part, facile and straightforward. Nevertheless, these approaches have several limitations, such as the use of toxic chemicals and production of toxic by-products with limited biocompatibility. Therefore, new methods are needed to address these limitations, and green chemistry offers a suitable and novel answer, with the safe and environmentally friendly design, manufacturing, and use of minimally toxic chemicals. Green chemistry approaches are especially useful for the generation of metallic nanoparticles or nanometric structures that can effectively and efficiently address health care concerns. Objective: Here, tellurium (Te) nanowires were synthesized using a novel green chemistry approach, and their structures and cytocompatibility were evaluated. Method: An easy and straightforward hydrothermal method was employed, and the Te nanowires were characterized using transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy, and optical microscopy for morphology, size, and chemistry. Cytotoxicity tests were performed with human dermal fibroblasts and human melanoma cells (to assess anticancer properties). The results showed that a treatment with Te nanowires at concentrations between 5 and 100 µg/mL improved the proliferation of healthy cells and decreased cancerous cell growth over a 5-day period. Most importantly, the green chemistry -synthesized Te nanowires outperformed those produced by traditional synthetic chemical methods. Conclusion: This study suggests that green chemistry approaches for producing Te nanostructures may not only reduce adverse environmental effects resulting from traditional synthetic chemistry methods, but also be more effective in numerous health care applications.


Assuntos
Antineoplásicos/farmacologia , Química Verde/métodos , Nanopartículas Metálicas/química , Nanofios/química , Telúrio/química , Morte Celular , Linhagem Celular Tumoral , Fibroblastos/citologia , Fibroblastos/ultraestrutura , Humanos , Concentração Inibidora 50 , Melanoma/patologia , Melanoma/ultraestrutura , Nanopartículas Metálicas/ultraestrutura , Nanofios/ultraestrutura , Espectroscopia Fotoeletrônica , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
11.
Colloids Surf B Biointerfaces ; 180: 401-410, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31082778

RESUMO

Cobalt nanowires (CoNWs) simultaneously possessing advantages in photothermal effect, targeting drug delivery and photoacoustic imaging property are hopefully promising strategies to further improve the treatment efficiency and reduce the side effects of cancer chemotherapy. Herein, a unique cobalt-based structure decorated with graphene oxide (GO) and polyethylene glycol (PEG) is fabricated through a facile approach. The resultant nanohybrids show relatively low cytotoxicity, favorable biocompatibility as well as inherit the outstanding properties of cobalt. Moreover, CoNWs decorated with GO and PEG (CoNWs-GO-PEG) can load therapeutic drug molecules (e.g., doxorubicin, DOX) with a high drug loading capacity (992.91 mg/g), and simultaneously they are responsive to pH, NIR (near-infrared) irradiation and magnetism stimulation. Accordingly, CoNWs-GO-PEG-DOX shows the satisfactory effect of eliminating cancer cells with synergistic chemo-photothermal therapy in vitro. Current work provides a solid demonstration of the potential of CoNWs-GO-PEG for serving as a targeted antitumor agent in synergistic chemo-photothermal therapy.


Assuntos
Cobalto/química , Hipertermia Induzida , Nanofios/química , Neoplasias/terapia , Fototerapia , Células 3T3 , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Doxorrubicina/farmacologia , Doxorrubicina/uso terapêutico , Liberação Controlada de Fármacos , Grafite/química , Hemólise/efeitos dos fármacos , Fenômenos Magnéticos , Camundongos , Nanofios/ultraestrutura , Neoplasias/tratamento farmacológico , Polietilenoglicóis/química , Coelhos , Propriedades de Superfície
12.
Mater Sci Eng C Mater Biol Appl ; 99: 1075-1091, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30889640

RESUMO

The choice of material types for tissue engineering scaffolds and the design of methods are contributive in yielding the proper result. In this study, 1-5% wt. Alumina nanowires are added to (Polyhydroxybutyrate-Chitosan) PHB-CTS alloy solution, and the scaffolds are prepared by electrospinning method. The fiber diameters, porosity percentages and uniform distribution of Alumina nanowires are assessed by SEM, EDS and TEM. The surface roughness of the fibers is confirmed by FESEM and AFM. The crystallinity of nanofibers is calculated by DSC and verified by FTIR. The tensile strength of the PHB-CTS scaffold increase up to >10 fold in presence of 3% wt. Alumina. Formation of calcium phosphate sediments only on the surface of Alumina containing scaffolds after 7 and 28 days of immersion in SBF is observed by SEM, and verified by XRD analysis. Proliferation and viability of MG-63 cells and alkaline phosphatase secretion are significantly higher on scaffolds containing Alumina than that of the PHB or PHB-CTS. The appropriate properties of Alumina which affected in cell behavior, hydrophilicity enhancement, bioactivity and mechanical properties make it contribution agent in bone tissue engineering.


Assuntos
Óxido de Alumínio/farmacologia , Osso e Ossos/fisiologia , Quitosana/farmacologia , Hidroxibutiratos/farmacologia , Nanofios/química , Poliésteres/farmacologia , Engenharia Tecidual/métodos , Tecidos Suporte/química , Fosfatase Alcalina/metabolismo , Osso e Ossos/efeitos dos fármacos , Linhagem Celular Tumoral , Forma Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Humanos , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Imageamento Tridimensional , Nanofibras/química , Nanofibras/ultraestrutura , Nanofios/ultraestrutura , Porosidade , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Água/química
13.
Nanotechnology ; 30(21): 214003, 2019 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-30699399

RESUMO

Due to their high aspect ratio and increased surface-to-foot-print area, arrays of vertical semiconductor nanowires are used in numerous biological applications, such as cell transfection and biosensing. Here we focus on two specific valuable biosensing approaches that, so far, have received relatively limited attention in terms of their potential capabilities: cellular mechanosensing and lightguiding-induced enhanced fluorescence detection. Although proposed a decade ago, these two applications for using vertical nanowire arrays have only very recently achieved significant breakthroughs, both in terms of understanding their fundamental phenomena, and in the ease of their implementation. We review the status of the field in these areas and describe significant findings and potential future directions.


Assuntos
Técnicas Biossensoriais , Mecanotransdução Celular/fisiologia , Nanofios/química , Semicondutores , Biomarcadores/urina , Linhagem Celular , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Humanos , Interleucina-8/urina , Luz , Células MCF-7 , Subfragmentos de Miosina/química , Subfragmentos de Miosina/metabolismo , Nanofios/ultraestrutura , Espectrometria de Fluorescência/métodos , Fator de Necrose Tumoral alfa/urina , Xylella/citologia , Xylella/fisiologia , Óxido de Zinco/química
14.
Bioelectrochemistry ; 125: 38-45, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30261369

RESUMO

In this work, low cost α-MnO2 nanowires and α-MnO2 nanowires supported on carbon Vulcan (α-MnO2/C) have been synthesized via a simple and facile hydrothermal method for application in microbial fuel cells. The prepared samples have been characterized by X-ray diffraction (XRD), Raman spectroscopy and field emission scanning electron microscopy (FE-SEM). Electrocatalytic activities of the samples have been evaluated by means of cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) in a neutral phosphate buffer solution. EIS was performed at different potentials to gain further insight into the kinetic properties of α-MnO2/C. Both catalysts were used in air cathode microbial fuel cells to achieve power densities of 180 and 111 mWm-2 for α-MnO2/C and pristine α-MnO2 nanowires, respectively. α-MnO2/C functions as a good and economical alternative for Pt free catalysts in practical MFC applications, as shown by the findings of stability test and voltage generation cycles in long-term operation of MFC.


Assuntos
Fontes de Energia Bioelétrica/economia , Compostos de Manganês/química , Nanofios/química , Óxidos/química , Oxigênio/química , Carbono/química , Catálise , Técnicas Eletroquímicas , Eletrodos/economia , Compostos de Manganês/economia , Nanofios/economia , Nanofios/ultraestrutura , Oxirredução , Óxidos/economia
15.
Bioelectrochemistry ; 125: 90-96, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30342231

RESUMO

Biocompatible materials, such as zwitterionic poly(carboxybetaine methacrylate) (polyCBMA), are of extraordinary importance in growth of bioelectronics and biosensors, because they not only greatly suppress nonspecific protein adsorption, but also have rich functional groups to facilitate the fixation of biological molecules. A novel nanocomposite was synthesized herein through modification polyCBMA onto conducting polymer polyaniline (PANI) nanowire surface. The prepared polyCBMA/PANI composite, integrating the good conductivity of PANI nanowires with the excellent antifouling capability of polyCBMA, provided a wonderful matrix for the growth of ultrasensitive and low fouling biosensor. Carcinoembryonic antigen (CEA), an important biomarker for a variety of cancers, was utilized as a model test. Furthermore its antibody was fixed onto polyCBMA/PANI for the preparation of CEA biosensor. DPV was applied as a sensing principle with information at which peak potential and current the signals were recorded. The peak currents were in inverse proportion to the logarithm of CEA concentration in the range from 1.0×10-14gmL-1 to 1.0×10-10gmL-1, with a detect limit of 3.05fgmL-1. Furthermore, this low fouling, label-free biosensor has been utilized for assaying in undiluted human serum samples with resisting serious nonspecific protein adsorption, demonstrating its feasible potential application in clinical analysis of CEA.


Assuntos
Compostos de Anilina/química , Anticorpos Imobilizados/química , Betaína/química , Técnicas Biossensoriais/métodos , Antígeno Carcinoembrionário/sangue , Nanofios/química , Ácidos Polimetacrílicos/química , Condutividade Elétrica , Técnicas Eletroquímicas/métodos , Humanos , Imunoensaio/métodos , Limite de Detecção , Nanofios/ultraestrutura
16.
ACS Sens ; 3(11): 2385-2393, 2018 11 26.
Artigo em Inglês | MEDLINE | ID: mdl-30387341

RESUMO

Though the chemical origin of a metal oxide gas sensor is widely accepted to be the surface reaction of detectants with ionsorbed oxygen, how the sensing material transduces the chemical reaction into an electrical signal (i.e., resistance change) is still not well-recognized. Herein, the single ZnO NW is used as a model to investigate the relationship between the microstructure and sensing performance. It is found that the acetone responses arrive at the maximum at the NW diameter ( D) of ∼110 nm at the D range of 80 to 400 nm, which is temperature independent in the temperature region of 200 °C-375 °C. The electrical properties of the single NW field effect transistors illustrate that the electron mobility decreases but electron concentration increases with the D ranging from ∼60 nm to ∼150 nm, inferring the good crystal quality of thinner ZnO NWs and the abundant crystal defects in thicker NWs. Subsequently, the surface charge layer ( L) is calculated to be a constant of 43.6 ± 3.7 nm at this D range, which cannot be explained by the conventional D- L model in which the gas-sensing maximum appears when D approximates 2 L. Furthermore, the crystal defects in the single ZnO NW are probed by employing the microphotoluminescence technique. The mechanism is proposed to be the compromise of the two kinds of crystal defects in ZnO (i.e., more donors and fewer acceptors favor the gas-sensing performance), which is again verified by the gas sensors based on the NW contacts.


Assuntos
Nanofios/química , Óxido de Zinco/química , Acetona/análise , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Gases/análise , Nanofios/ultraestrutura , Temperatura
17.
ACS Appl Mater Interfaces ; 10(47): 40880-40889, 2018 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-30387980

RESUMO

Increasingly serious electromagnetic radiation pollution puts higher demands on wearable devices. Electronic sensor skin capable of shielding electromagnetic radiation can provide extra protection in emerging fields such as electronic skins, robotics, and artificial intelligence, but combining the sensation and electromagnetic shielding performance together remains a great challenge. Here, inspired by the structure and functions of the human skin, a multifunctional electronic skin (M-E-skin) with both tactile sensing and electromagnetic radiation shielding functions is proposed. The tactile sensing of human skin is mimicked with irregular dermislike rough surfaces, and the electromagnetic shielding performance not available on natural skin is introduced by mimicking the ultraviolet electromagnetic radiation absorption of melanin in epidermis. The M-E-skin shows superior sensitivity (9.8 × 104 kPa-1 for the pressure range 0-0.2 kPa and 3.5 × 103 kPa-1 within 0.2-20 kPa), broad operating range (0-20 kPa), fast response and relaxation times (<62.5 ms), great pressuring-relaxing stability (10 kPa, 1000 cycles), low operating voltage (0.1 V), low power consumption (1.5 nW), and low detection limit (5 Pa). Besides, a broad range of electromagnetic wave (0.5-7.5 GHz) is shielded more than 99.66% by the M-E-skin. This work holds great potential to enlarge the application scope of current electronic skins.


Assuntos
Biomimética , Fenômenos Eletromagnéticos , Sensação , Dispositivos Eletrônicos Vestíveis , Humanos , Nanofios/ultraestrutura , Prata/química
18.
Sci Rep ; 8(1): 15832, 2018 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-30361540

RESUMO

The inactivation of pathogens in liquids has broad applications, ranging from water disinfection to food pasteurization. However, common cell inactivation methods (e.g., chlorination, ultraviolet radiation and thermal treatment) have significant drawbacks such as carcinogenic byproduct formation, energy intensiveness and/or nutrient structure destruction. Here, we fabricated a new approach to address these challenges by applying a low-voltage electroporation disinfection cell (EDC) and investigate the critical mechanisms of cell transport to allow high inactivation performance. The EDC prototypes were equipped with two one-dimensional (1D) nanostructure-assisted electrodes that enabled high electric field strength (>107 V m-1) near the electrode surface with a low applied voltage (1 V). We have identified that during electroporation disinfection, electrophoresis, dielectrophoresis and hydraulic flow are the three major mechanisms which transport cells into the vicinity of the electrode surface to achieve superior disinfection performance. The EDC treated 70 ml of bacteria sample with an initial cell concentration of 107 CFU ml-1 and achieved complete bacteria inactivation (survival rate <0.00001%; no live bacteria detected). Our findings will help to establish a foundation for the future development and implementation of low-voltage electroporation for cell inactivation.


Assuntos
Eletroporação/métodos , Escherichia coli/citologia , Viabilidade Microbiana , Transporte Biológico , Simulação por Computador , Desinfecção , Escherichia coli/ultraestrutura , Nanofios/ultraestrutura
19.
J Biomed Mater Res A ; 106(12): 3099-3110, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30325096

RESUMO

Periodontitis is an inflammatory disease leading to tooth loss, alveolar bone absorption and disorder of masticatory function. Guided tissue regeneration (GTR) is one of the most common strategies for regeneration of lost periodontium. During surgical process, barrier membranes, and osteoinductive/osteoconductive materials should be placed, respectively, which may increase risks of infection, bleeding, and difficulty of operation. Here, we introduced a new kind of hydroxyapatite (HAp) nanowires modified polylactic acid (PLA) membrane to achieve barrier/osteoinduction dual functions. The physicochemical property measurements suggested the two sides of the composite membrane did not change after composition. Then a rat mandibular defect model was established to investigate barrier and osteoinductive effects of this composite membrane. After implantation, effects of functional cells engraftment and osteoinduction were detected by scanning electron microscope (SEM), histomorphometric measurement, immunohistochemical staining, and Micro-CT scanning. SEM images showed HAp side engrafted more cells than PLA side. The result of immunohistochemical staining suggested HAp/PLA promoted the expression of bone-related markers. Moreover, there were more newly formed bones with better quality in HAp/PLA group. Therefore, this composite membrane would be a promising biomaterial in tissue engineering for bone regeneration due to its barrier/osteoinduction dual functions. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 3099-3110, 2018.


Assuntos
Regeneração Óssea , Substitutos Ósseos/uso terapêutico , Durapatita/uso terapêutico , Traumatismos Mandibulares/terapia , Nanofios/uso terapêutico , Poliésteres/uso terapêutico , Animais , Regeneração Óssea/efeitos dos fármacos , Substitutos Ósseos/química , Durapatita/química , Masculino , Mandíbula/efeitos dos fármacos , Mandíbula/patologia , Mandíbula/fisiologia , Traumatismos Mandibulares/patologia , Nanofios/química , Nanofios/ultraestrutura , Poliésteres/química , Ratos , Ratos Wistar
20.
J Biomater Appl ; 33(3): 352-362, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30223735

RESUMO

Polymer-based drug-eluting stents (DESs) represented attractive application for the treatment of cardiovascular diseases; however, polymer coating has caused serious adverse responses to tissues such as chronic inflammation due to acidic by-products. Therefore, polymer-free DESs have recently emerged as promising candidates for the treatment; however, burst release of drug(s) from the surface limited its applications. In this study, we focused on delivery of therapeutic drug from polymer-free (or -less) DESs through surface modification using cobalt oxide nanowires (Co3O4 NWs) to improve and control the drug release. The results demonstrated that Co3O4 NWs could be simply fabricated on cobalt-chromium substrate by ammonia-evaporation-induced method. The Co3O4 NWs were uniformly arrayed with diameters of 50-100 nm and lengths of 10 µm. It was found that Co3O4 NWs were comparatively stable without any delamination or change of the morphology under in vitro long-term stability using circulating system. Sirolimus was used as a model drug for studying in vitro release behavior under physiological conditions. The sirolimus release behavior from flat cobalt-chromium showed an initial burst (over 90%) after one day. On the other hand, Co3O4 NWs presented a sustained sirolimus release rate for up to seven days. Similarly, the polymer-less specimens on Co3O4 NWs substrates sustained sirolimus release for a longer-period of time when compared to flat Co-Cr substrates. In summary, the current approach of using Co3O4 NWs-based substrates might have a great potential to sustain drug release for drug-eluting implants and medical devices including stents.


Assuntos
Anti-Infecciosos/administração & dosagem , Cobalto/química , Preparações de Ação Retardada/química , Stents Farmacológicos , Nanofios/química , Óxidos/química , Sirolimo/administração & dosagem , Ligas/química , Anti-Infecciosos/química , Cromo/química , Liberação Controlada de Fármacos , Nanofios/ultraestrutura , Sirolimo/química
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