RESUMO
As one of the most important smart materials, fluorescent hydrogel actuators can produce both color and shape changes under external stimuli. In the present work, an effective approach to develop a novel fluorescent hydrogel actuator with pH and thermo dual responsiveness is proposed. Through incorporating pH-responsive perylene tetracarboxylic acid (PTCA), which is a typical fluorescent moiety with aggregation-caused quenching (ACQ) effect, into an anisotropic poly(N-isopropylacrylamide)-polyacrylamide (PNIPAm-PAAm) structure, the obtained hydrogel exhibits stable thermoresponsive shape deformation and switchable fluorescence performance upon a pH trigger. Therefore, fluorescence-quenching-based and actuation-based information can be revealed when exposed to UV light and immersed into warm water, respectively. Moreover, the thermoresponsive actuating behavior can be applied to further hide the fluorescence-quenching-based images. The present work may provide new insights into the design and preparation of novel stimuli-responsive hydrogel actuators.
Assuntos
Corantes Fluorescentes/química , Hidrogel de Polietilenoglicol-Dimetacrilato/química , Temperatura , Fluorescência , Concentração de Íons de Hidrogênio , Tamanho da Partícula , Propriedades de SuperfícieRESUMO
Distraction osteogenesis (DO) is a widely used self-tissue engineering. However, complications and discomfort due to the long treatment period are still the bottleneck of DO. Novel strategies to accelerate bone formation in DO are still needed. P38 is capable of regulating the osteogenic differentiation of both mesenchymal stem cells (MSCs) and osteoblasts, which are crucial to bone regeneration. However, it is not clear whether targeting p38 could regulate bony formation in DO. The purpose of the current work was to investigate the effects of local application of either p38 agonist anisomycin or p38 inhibitor SB203580 in a rat model of DO. 30 adult rats were randomly divided into 3 groups: (A) rats injected with DMSO served as the control group; (B) rats injected with p38 agonist anisomycin; (C) rats injected with p38 inhibitor SB203580. All the rats were subjected to mandibular distraction and the injection was performed daily during this period. The distracted mandibles were harvested on days 15 and 30 after surgery and subjected to the following analysis. Micro-computed tomography and histological evaluation results showed that local application of p38 agonist anisomycin increased new bone formation in DO, whereas p38 inhibitor SB203580 decreased it. Immunohistochemical analysis suggested that anisomycin promoted MSC recruitment in the distraction gap. In conclusion, this study demonstrated that local application of p38 agonist anisomycin can increase new bone formation during DO. This study may lead to a novel cell-based strategy for the improvement of bone regeneration.
Assuntos
Anisomicina/farmacologia , Regeneração Óssea/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Células-Tronco Mesenquimais/efeitos dos fármacos , Osteogênese por Distração/métodos , Osteogênese/efeitos dos fármacos , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Animais , Inibidores Enzimáticos/farmacologia , Imidazóis/farmacologia , Masculino , Mandíbula/fisiologia , Mandíbula/cirurgia , Células-Tronco Mesenquimais/enzimologia , Células-Tronco Mesenquimais/fisiologia , Piridinas/farmacologia , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Microtomografia por Raio-X , Proteínas Quinases p38 Ativadas por Mitógeno/antagonistas & inibidoresRESUMO
A new strategy for fabricating glucose biosensor was presented by layer-by-layer assembled chitosan (CS)/gold nanoparticles (GNp)/glucose oxidase (GOD) multilayer films modified Pt electrode. First, a cleaned Pt electrode was immersed in poly(allylamine) (PAA), and then transferred to GNp, followed by the adsorption of GOD (GOD/GNp/PAA/Pt). Second, the GOD/GNp/PAA/Pt electrode was immersed in CS, and then transferred to GNp, followed by the adsorption of GOD (GOD/GNp/CS/GOD/GNp/PAA/Pt). Third, different layers of multilayer films modified Pt electrodes were assembled by repeating the second process. Film assembling and characterization were studied by quart crystal microbalance, and properties of the resulting glucose biosensors were measured by electrochemical measurements. The results confirmed that the assembling process of multilayer films was simple to operate, the immobilized GOD displayed an excellent catalytic property to glucose, and GNp in the biosensing interface efficiently improved the electron transfer between analyte and electrode surface. The amperometric response of the biosensors uniformly increased from one to six layers of multilayer films, and then reached saturation after the seven layers. Among the resulting biosensors, the biosensor based on the six layers of multilayer films was best. It showed a wide linear range of 0.5-16 mM, with a detection limit of 7.0 microM estimated at a signal-to-noise ratio of 3, fast response time (within 8s). Moreover, it exhibited good reproducibility, long-term stability and interference free. This method can be used for constructing other thin films, which is a universal immobilization method for biosensor fabrication.
Assuntos
Técnicas Biossensoriais/instrumentação , Quitosana/química , Eletroquímica/instrumentação , Glucose Oxidase/química , Glucose/análise , Microeletrodos , Platina/química , Técnicas Biossensoriais/métodos , Materiais Revestidos Biocompatíveis/química , Cristalização/métodos , Eletroquímica/métodos , Enzimas Imobilizadas/química , Desenho de Equipamento , Análise de Falha de Equipamento , Ouro/química , Membranas Artificiais , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
The major challenge in current clinic contrast agents (CAs) and chemotherapy is the poor tumor selectivity and response. Based on the self-quench property of IR820 at high concentrations, and different contrast effect ability of Gd-DOTA between inner and outer of liposome, we developed "bomb-like" light-triggered CAs (LTCAs) for enhanced CT/MRI/FI multimodal imaging, which can improve the signal-to-noise ratio of tumor tissue specifically. IR820, Iohexol and Gd-chelates were firstly encapsulated into the thermal-sensitive nanocarrier with a high concentration. This will result in protection and fluorescence quenching. Then, the release of CAs was triggered by near-infrared (NIR) light laser irradiation, which will lead to fluorescence and MRI activation and enable imaging of inflammation. In vitro and in vivo experiments demonstrated that LTCAs with 808 nm laser irradiation have shorter T1 relaxation time in MRI and stronger intensity in FI compared to those without irradiation. Additionally, due to the high photothermal conversion efficiency of IR820, the injection of LTCAs was demonstrated to completely inhibit C6 tumor growth in nude mice up to 17 days after NIR laser irradiation. The results indicate that the LTCAs can serve as a promising platform for NIR-activated multimodal imaging and photothermal therapy.
Assuntos
Meios de Contraste/química , Imagem Multimodal/métodos , Neoplasias Experimentais/diagnóstico por imagem , Animais , Feminino , Compostos Heterocíclicos/química , Humanos , Verde de Indocianina/análogos & derivados , Verde de Indocianina/química , Raios Infravermelhos , Lipossomos/química , Imageamento por Ressonância Magnética/métodos , Camundongos Endogâmicos BALB C , Camundongos Nus , Imagem Multimodal/instrumentação , Neoplasias/patologia , Neoplasias Experimentais/terapia , Compostos Organometálicos/química , Fototerapia/métodos , Razão Sinal-Ruído , Nanomedicina Teranóstica/instrumentação , Nanomedicina Teranóstica/métodosRESUMO
Recent advances in serial block-face imaging using scanning electron microscopy (SEM) have enabled the rapid and efficient acquisition of 3-dimensional (3D) ultrastructural information from a large volume of biological specimens including brain tissues. However, volume imaging under SEM is often hampered by sample charging, and typically requires specific sample preparation to reduce charging and increase image contrast. In the present study, we introduced carbon-based conductive resins for 3D analyses of subcellular ultrastructures, using serial block-face SEM (SBF-SEM) to image samples. Conductive resins were produced by adding the carbon black filler, Ketjen black, to resins commonly used for electron microscopic observations of biological specimens. Carbon black mostly localized around tissues and did not penetrate cells, whereas the conductive resins significantly reduced the charging of samples during SBF-SEM imaging. When serial images were acquired, embedding into the conductive resins improved the resolution of images by facilitating the successful cutting of samples in SBF-SEM. These results suggest that improving the conductivities of resins with a carbon black filler is a simple and useful option for reducing charging and enhancing the resolution of images obtained for volume imaging with SEM.
Assuntos
Resinas Epóxi/química , Imageamento Tridimensional/métodos , Microscopia Eletrônica de Varredura/métodos , Fuligem/química , Animais , Encéfalo/ultraestrutura , Condutividade Elétrica , Rim/ultraestrutura , Camundongos Endogâmicos C57BL , Reprodutibilidade dos Testes , Manejo de Espécimes/métodosRESUMO
A new physical method, namely boiling treatment, was developed to aid flotation separation of acrylonitrile-butadiene-styrene (ABS) and polystyrene (PS) plastics. Boiling treatment was shown to be effective in producing a hydrophilic surface on ABS plastic. Fourier Transform Infrared analysis was conducted to investigate the mechanism of boiling treatment of ABS. Surface rearrangement of polymer may be responsible for surface change of boiling treated ABS, and the selective influence of boiling treatment on the floatability of boiling treated plastics may be attributed to the difference in the molecular mobility of polymer chains. The effects of flotation time, frother concentration and particle size on flotation behavior of simple plastic were investigated. Based on flotation behavior of simple plastic, flotation separation of boiling treatment ABS and PS with different particle sizes was achieved efficiently. The purity of ABS and PS was up to 99.78% and 95.80%, respectively; the recovery of ABS and PS was up to 95.81% and 99.82%, respectively. Boiling treatment promotes the industrial application of plastics flotation and facilitates plastic recycling.
Assuntos
Resinas Acrílicas/química , Butadienos/química , Polímeros/química , Poliestirenos/química , Eliminação de Resíduos/métodos , Interações Hidrofóbicas e Hidrofílicas , Tamanho da Partícula , ReciclagemRESUMO
OBJECTIVE: To study the effect and the key points in the operative procedure of the one-stage reconstruction of postburn whole auricle defect with medpor car scaffold covered with superficial temporoparietal fascia (TPF) flap. METHODS: Medpor car scaffold was embedded under the superficial temporal (TFP) fascia. Razor-thin skin was grafted onto the surface of the fascia flap. RESULTS: Fifteen patients with postburn whole auricle defect were treated by one-stage reconstruction with Medpor ear scaffold during the last four years. It was successful in all the patients with satisfactory appearance of the reconstructed ears. CONCLUSION: Medpor possessed friendly biological compatibility. The reconstruction gave satisfactory results, and its advantages consisted of short operational time, easy manipulation, less injury to patients and good auricular contour.