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1.
Theranostics ; 14(6): 2605-2621, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38646639

RESUMO

Rationale: Nab-paclitaxel (Abx) is widely employed in malignant tumor therapy. In tumor cells and pro-tumoral M2-type macrophages, the IL4 receptor (IL4R) is upregulated. This study aimed to elucidate the selective delivery of Abx to M2-type macrophages by targeting IL4R and reprogramming them into an anti-tumoral M1-type. Methods: Abx was conjugated with the IL4R-binding IL4RPep-1 peptide using click chemistry (IL4R-Abx). Cellular internalization, macrophage reprogramming and signal pathways, and tumor growth and metastasis by IL4R-Abx were examined. Results: IL4R-Abx was internalized into M2 macrophages more efficiently compared to the unmodified Abx and control peptide-conjugated Abx (Ctrl-Abx), which was primarily inhibited using an anti-IL4R antibody and a receptor-mediated endocytosis inhibitor compared with a macropinocytosis inhibitor. IL4R-Abx reprogrammed the M2-type macrophages into M1-like phenotype and increased reactive oxygen species (ROS) levels and extracellular release of high mobility group box 1 (HMGB1) in M2 macrophages at higher levels than Abx and Ctrl-Abx. The conditioned medium of IL4R-Abx-treated M2 macrophages skewed M2 macrophages into the M1-like phenotype, in which an anti-HMGB1 antibody and a toll-like receptor 4 (TLR4) inhibitor induced a blockade. IL4R-Abx accumulated at tumors, heightened immune-stimulatory cells while reducing immune-suppressing cells, and hampered tumor growth and metastasis in mice more efficiently than Abx and Ctrl-Abx. Conclusions: These results indicate that IL4R-targeting allows enhancement of M2-macrophage shaping into M1-like phenotype by Abx through the ROS-HMGB1-TLR4 axis, improvement of antitumor immunity, and thereby inhibition of tumor growth and metastasis, presenting a new approach to cancer immunotherapy.


Assuntos
Albuminas , Proteína HMGB1 , Macrófagos , Paclitaxel , Espécies Reativas de Oxigênio , Receptor 4 Toll-Like , Animais , Receptor 4 Toll-Like/metabolismo , Proteína HMGB1/metabolismo , Camundongos , Espécies Reativas de Oxigênio/metabolismo , Macrófagos/metabolismo , Macrófagos/efeitos dos fármacos , Paclitaxel/farmacologia , Albuminas/metabolismo , Receptores de Interleucina-4/metabolismo , Linhagem Celular Tumoral , Transdução de Sinais/efeitos dos fármacos , Humanos , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Neoplasias/metabolismo , Camundongos Endogâmicos C57BL , Fenótipo , Camundongos Endogâmicos BALB C , Metástase Neoplásica , Feminino
2.
ACS Nano ; 18(1): 199-209, 2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38109681

RESUMO

Tumor-derived extracellular vesicles (TDEs) have potential for therapeutic cancer vaccine applications since they innately possess tumor-associated antigens, mediate antigen presentation, and can incorporate immune adjuvants for enhanced vaccine efficacy. However, the original TDEs also contain immune-suppressive proteins. To address this, we proposed a simple yet powerful preconditioning method to improve the overall immunogenicity of the TDEs. This approach involved inducing endoplasmic reticulum (ER) stress on parental tumor cells via N-glycosylation inhibition with tunicamycin. The generated immunogenic TDEs (iTDEs) contained down-regulated immunosuppressive proteins and up-regulated immune adjuvants, effectively activating dendritic cells (DCs) in vitro. Furthermore, in vivo evidence from a tumor-bearing mouse model showed that iTDEs activated DCs, enabling cytotoxic T lymphocytes (CTLs) to target tumors, and eventually established a systemic antitumor immune response. Additionally, iTDEs significantly delayed tumor recurrence in a postsurgery model compared with control groups. These findings highlight the immense potential of our strategy for utilizing TDEs to develop effective cancer vaccines.


Assuntos
Vacinas Anticâncer , Vesículas Extracelulares , Neoplasias , Camundongos , Animais , Vacinas Anticâncer/uso terapêutico , Neoplasias/terapia , Linfócitos T Citotóxicos , Adjuvantes Imunológicos , Retículo Endoplasmático , Células Dendríticas
3.
Nat Commun ; 14(1): 8282, 2023 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-38092772

RESUMO

Structural variants (SVs), accounting for a larger fraction of the genome than SNPs/InDels, are an important pool of genetic variation, enabling environmental adaptations. Here, we perform long-read sequencing data of 320 Tibetan and Han samples and show that SVs are highly involved in high-altitude adaptation. We expand the landscape of global SVs, apply robust models of selection and population differentiation combining SVs, SNPs and InDels, and use epigenomic analyses to predict enhancers, target genes and biological functions. We reveal diverse Tibetan-specific SVs affecting the regulatory circuitry of biological functions, including the hypoxia response, energy metabolism and pulmonary function. We find a Tibetan-specific deletion disrupts a super-enhancer and downregulates EPAS1 using enhancer reporter, cellular knock-out and DNA pull-down assays. Our study expands the global SV landscape, reveals the role of gene-regulatory circuitry rewiring in human adaptation, and illustrates the diverse functional roles of SVs in human biology.


Assuntos
Altitude , Genoma , Humanos , Hipóxia/genética , Análise de Sequência de DNA , Adaptação Fisiológica/genética
4.
Res Sq ; 2023 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-36711714

RESUMO

Legg-Calvé-Perthes disease is juvenile idiopathic osteonecrosis of the femoral head (ONFH) that has no effective clinical resolutions. Previously, local injection of bone morphogenetic protein-2 (BMP2) for ONFH treatment showed a heterogeneous bone repair and a high incidence of heterotopic ossification (HO) due to the BMP2 leakage. Here, we developed a BMP2-hydrogel treatment via a transphyseal bone wash and subsequential injection of BMP2-loaded hydrogel. In vivo studies showed that a hydrogel of gelatin-heparin-tyramine retained the BMP2 for four weeks. The injection of the hydrogel can efficiently prevent leakage. With the bone wash, the injected hydrogel had a broad distribution in the head. In vivo studies on pigs revealed that the BMP2-hydrogel treatment produced a homogeneous bone regeneration without HO. It preserved the subchondral contour and restored the subchondral endochondral ossification, although it increased growth plate fusions. In summary, the study demonstrated a promising BMP2-hydrogel treatment for ONFH treatment, especially for teenagers.

5.
Nanomaterials (Basel) ; 14(1)2023 12 26.
Artigo em Inglês | MEDLINE | ID: mdl-38202527

RESUMO

The thermomechanical properties of carbon fiber reinforced silicon carbide ceramic matrix composites (Cf/SiC CMCs) were studied up to 2000 °C using high-temperature in situ flexural testing in argon. The CMC specimens were fabricated using an ultrahigh concentration (66 vol%) aqueous slurry containing nano-sized silicon carbide powder. The SiC powder compacts were obtained by drying the slurry and were densified using the precursor impregnation and pyrolysis (PIP) method with field assisted sintering technology/spark plasma sintering (FAST/SPS). The high relative density of the SiC green body (77.6%) enabled densification within 2.5 days using four PIP cycles. In contrast, conventional PIP processes take over 7 days. The in situ flexural strength of the Cf/SiC CMC was 434 MPa at 1750 °C, which was 84% higher than the room temperature value. The value further increased to 542 MPa at 2000 °C. Possible mechanisms to explain the excellent strength of the CMC at elevated temperatures are discussed.

6.
Pharmaceutics ; 14(12)2022 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-36559097

RESUMO

Doxorubicin (DOX) is a representative anticancer drug with a unique ability to induce immunogenic cell death of cancer cells. However, undesired toxicity on immune cells has remained a significant challenge, hindering the usage of DOX in cancer immunotherapy. Here, we report a combined therapy to avoid the off-target toxicity of DOX by adapting ultrasound-responsive liposomal doxorubicin and focused ultrasound exposure. Histological analysis demonstrated that the combined therapy induced less hemosiderosis of splenocytes and improved tumor infiltration of cytotoxic T lymphocytes. Additionally, in vivo therapeutic evaluation results indicate that the combined therapy achieved higher efficacy when combined with PD-1 immune-checkpoint blockade therapy by improving immunogenicity.

7.
Materials (Basel) ; 15(19)2022 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-36234288

RESUMO

The degradation behavior of yttria-stabilized zirconia by thermal aging was investigated in terms of phase transformation, local atomic structure, and electrical conductivity. The average grain size of 8YSZ was increased from 20.83 µm to 25.81 µm with increasing aging temperature. All 8YSZ samples degraded at different temperatures had a predominantly cubic structure. The (400) peak of 8YSZ deteriorated at 1300 and 1400 °C shifted to a high angle, and the peak of tetragonal was not indexed. For 8YSZ degraded at 1500 °C, the (400) peak shifted to a lower angle, and the peak of tetragonal was identified. Analysis of the local microstructure of aged 8YSZ using extended X-ray absorption fine structure showed that the intensity of the Zr-O peak gradually increased and that the intensity of the peak of cationic Zr decreased as the aging temperature increased. The changes in the peaks indicate that the oxygen vacancies were reduced and Y3+ ions escaped from the lattice, leading to the destabilization of 8YSZ. The activation energies of 8YSZ at 1300 °C and 1400 °C were derived to be 0.86 and 0.87 eV, respectively, and the activation energy of 8YSZ at 1500 °C increased significantly to 0.92 eV. With the thermal deterioration of 8YSZ, the cation (Y3+) escaped from the lattice and the number of oxygen vacancies decreased, resulting in the formation of a tetragonal structure and high activation energy at 1500 °C.

8.
Front Physiol ; 12: 780312, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34899399

RESUMO

Brown and beige adipocytes are specialized to dissipate energy as heat. Sgk2, encoding a serine/threonine kinase, has been identified as a brown and beige adipocyte-specific gene in rodents and humans; however, its function in brown/beige adipocytes remains unraveled. Here, we examined the regulation and role of Sgk2 in brown/beige adipose tissue thermogenesis. We found that transcriptional coactivators PGC-1α and NT-PGC-1α activated by the ß3 adrenergic receptor-cAMP-PKA pathway are recruited to the Sgk2 promoter, triggering Sgk2 transcription in response to cold. SGK2 elevation was closely associated with increased serine/threonine phosphorylation of proteins carrying the consensus RxRxxS/T phosphorylation site. However, despite cold-dependent activation of SGK2, mice lacking Sgk2 exhibited normal cold tolerance at 4°C. In addition, Sgk2+/+ and Sgk2-/- mice induced comparable increases in energy expenditure during pharmacological activation of brown and beige adipose tissue with a ß3AR agonist. In vitro loss- and gain-of-function studies further demonstrated that Sgk2 ablation or activation does not alter thermogenic gene expression and mitochondrial respiration in brown adipocytes. Collectively, our results reveal a new signaling component SGK2, although dispensable for cold-induced thermogenesis that adds an additional layer of complexity to the ß3AR signaling network in brown/beige adipose tissue.

9.
Carbohydr Polym ; 158: 133-140, 2017 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-28024536

RESUMO

We describe the nanocomposite membrane for cell encapsulation using nanocelluose hydrogels. One of the surfaces of bacterial cellulose (BC) pellicles was coated with collagen to enhance cell adhesion and the opposite side of the BC pellicles was coated with alginate to protect transplanted cells from immune rejection by the reduced pore size of the composite membrane. The morphology of nanocomposite membrane was observed by scanning electron microscopy and the permeability of the membrane was estimated by the release test using different molecular weights of polymer solution. The nanocomposite membrane was permeable to small molecules but impermeable to large molecules such as IgG antibodies inferring the potential use in cell implantation. In addition, the BC-based nanocomposite membrane showed a superior mechanical property due to the incorporation of compared with alginate membranes. The cells attached efficiently to the surface of BC composite membranes with a high level of cell viability as well as bioactivity. Cells grown on the BC composite membrane kit released dopamine freely to the medium through the membrane, which showed that the BC composite membrane would be a promising cell encapsulation material in implantation.


Assuntos
Celulose/química , Colágeno/química , Nanocompostos , Polissacarídeos Bacterianos/química , Animais , Hidrogéis , Microscopia Eletrônica de Varredura , Células PC12 , Ratos
10.
Physiol Rep ; 4(20)2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27798359

RESUMO

The transcriptional coactivator PGC-1α plays a central role in hepatic gluconeogenesis. We previously reported that alternative splicing of the PGC-1α gene produces an additional transcript encoding the truncated protein NT-PGC-1α NT-PGC-1α is co-expressed with PGC-1α and highly induced by fasting in the liver. NT-PGC-1α regulates tissue-specific metabolism, but its role in the liver has not been investigated. Thus, the objective of this study was to determine the role of hepatic NT-PGC-1α in the regulation of gluconeogenesis. Adenovirus-mediated expression of NT-PGC-1α in primary hepatocytes strongly stimulated the expression of key gluconeogenic enzyme genes (PEPCK and G6Pase), leading to increased glucose production. To further understand NT-PGC-1α function in hepatic gluconeogenesis in vivo, we took advantage of a previously reported FL-PGC-1α-/- mouse line that lacks full-length PGC-1α (FL-PGC-1α) but retains a slightly shorter and functionally equivalent form of NT-PGC-1α (NT-PGC-1α254). In FL-PGC-1α-/- mice, NT-PGC-1α254 was induced by fasting in the liver and recruited to the promoters of PEPCK and G6Pase genes. The enrichment of NT-PGC-1α254 at the promoters was closely associated with fasting-induced increase in PEPCK and G6Pase gene expression and efficient production of glucose from pyruvate during a pyruvate tolerance test in FL-PGC-1α-/- mice. Moreover, FL-PGC-1α-/- primary hepatocytes showed a significant increase in gluconeogenic gene expression and glucose production after treatment with dexamethasone and forskolin, suggesting that NT-PGC-1α254 is sufficient to stimulate the gluconeogenic program in the absence of FL-PGC-1α Collectively, our findings highlight the role of hepatic NT-PGC-1α in stimulating gluconeogenic gene expression and glucose production.


Assuntos
Gluconeogênese/genética , Glucose/metabolismo , Fígado/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Adenoviridae/genética , Animais , Hepatócitos/metabolismo , Masculino , Camundongos , Fatores de Transcrição/metabolismo
11.
Water Res ; 95: 134-41, 2016 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-26990838

RESUMO

Finding a striking peculiarity of nanomaterials and evaluating its feasibility for practical use are interesting topics of research. We investigated the application of nanozeolite's outstanding reactivity for a rapid and effective method for radioactive cesium removal in the wastewater generated from nuclear power plant accident, as a new concept. Extremely fast removal of cesium, even without stirring, was achieved by the nanozeolite at efficiencies never observed with bulk materials. The nanozeolite reached an adsorption equilibrium state within 1 min. Cesium adsorption by nanozeolite was demonstrated at reaction rates of orders of magnitude higher than that of larger zeolite phases. This observation was strongly supported by the positive correlation between the rate constant ratio (k2,bulk/k2,nano) and the initial Cs concentrations with a correlation coefficient (R(2)) of 0.99. A potential drawback of a nanoadsorbent is the difficulty of particle settling and separation because of its high dispersivity in solution. However, our results also demonstrated that the nanozeolite could be easily precipitated from the high-salt solution with ferric flocculant. The flocculation index reached a steady state within 10 min. A series of our experimental results met the goal of rapid processing in the case of emergency by applying the well-suited nanozeolite adsorption and flocculation.


Assuntos
Césio , Águas Residuárias , Adsorção , Radioisótopos de Césio , Cloreto de Sódio , Zeolitas
12.
Carbohydr Polym ; 140: 43-50, 2016 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-26876826

RESUMO

Here we describe a unique conductive bacterial cellulose (BC) composite with silicon nanoparticles (SiNPs) and polyaniline. BC was used as a template for binding SiNPs resulting in a very promising anode material for Li-ion rechargeable batteries that showed a high specific capacity. The surfaces of the SiNPs were modified with phytic acid to enhance the binding of aniline monomer to the surface. A conformal coating of polyaniline (PANi) was formed on the modified SiNPs by in situ polymerization of aniline monomers. We also found that the phytic acid on the SiNPs was critical to ensure encapsulation of SiNPs with PANi. In addition, the phosphoric acid-tagged surface of the SiNPs enhanced the adhesion of SiNPs to the BC fibers. The resulting three dimensional network of BC was flexible and provided stress dissipation in the conductive BC composites. Flexural testing of conductive BC composites showed stable electrical conductivity even after repetitive bending over 100 times.


Assuntos
Compostos de Anilina/química , Celulose/química , Condutividade Elétrica , Fenômenos Mecânicos , Nanocompostos/química , Nanopartículas/química , Silício/química , Modelos Moleculares , Conformação Molecular , Estresse Mecânico , Temperatura
13.
Chemosphere ; 150: 765-771, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26683820

RESUMO

In this study, the equilibrium, kinetics and thermodynamics of cesium adsorption by nanocrystalline mordenite were investigated under cesium contamination with high-salt solution, simulating the case of an operation and decommissioning of nuclear facilities or an accident during the processes. The adsorption rate constants were determined using a pseudo second-order kinetic model. The kinetic results strongly demonstrated that the cesium adsorption rate of nano mordenite is extremely fast, even in a high-salt solution, and much faster than that of micro mordenite. In the equilibrium study, the Langmuir isotherm model fit the cesium adsorption data of nano mordenite better than the Freundlich model, which suggests that cesium adsorption onto nano mordenite is a monolayer homogeneous adsorption process. The obtained thermodynamic parameters indicated that the adsorption involved a very stable chemical reaction. In particular, the combination of rapid particle dispersion and rapid cesium adsorption of the nano mordenite in the solution resulted in a rapid and effective process for cesium removal without stirring, which may offer great advantages for low energy consumption and simple operation.


Assuntos
Silicatos de Alumínio/química , Césio/química , Adsorção , Cinética , Cloreto de Sódio/análise , Soluções , Termodinâmica
14.
Biomaterials ; 58: 93-102, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25941786

RESUMO

Carbon nanotubes (CNTs) have shown great potential in biomedical fields. However, in vivo applications of CNTs for regenerative medicine have been hampered by difficulties associated with the fabrication of three-dimensional (3D) scaffolds of CNTs due to CNTs' nano-scale nature. In this study, we devised a new method for biosynthesis of CNT-based 3D scaffold by in situ hybridizing CNTs with bacterial cellulose (BC), which has a structure ideal for tissue-engineering scaffolds. This was achieved simply by culturing Gluconacetobacter xylinus, BC-synthesizing bacteria, in medium containing CNTs. However, pristine CNTs aggregated in medium, which hampers homogeneous hybridization of CNTs with BC scaffolds, and the binding energy between hydrophobic pristine CNTs and hydrophilic BC was too small for the hybridization to occur. To overcome these problems, an amphiphilic comb-like polymer (APCLP) was adsorbed on CNTs. Unlike CNT-coated BC scaffolds (CNT-BC-Imm) formed by immersing 3D BC scaffolds in CNT solution, the APCLP-adsorbed CNT-BC hybrid scaffold (CNT-BC-Syn) showed homogeneously distributed CNTs throughout the 3D microporous structure of BC. Importantly, in contrast to CNT-BC-Imm scaffolds, CNT-BC-Syn scaffolds showed excellent osteoconductivity and osteoinductivity that led to high bone regeneration efficacy. This strategy may open a new avenue for development of 3D biofunctional scaffolds for regenerative medicine.


Assuntos
Celulose/química , Gluconacetobacter xylinus/química , Nanotubos de Carbono/química , Adsorção , Animais , Regeneração Óssea , Osso e Ossos/patologia , Coloides/química , Simulação por Computador , Feminino , Hibridização In Situ , Camundongos , Camundongos Endogâmicos ICR , Microscopia Eletrônica de Transmissão , Polímeros/química , Porosidade , Engenharia Tecidual/métodos , Alicerces Teciduais/química , Tomografia Computadorizada por Raios X
15.
Colloids Surf B Biointerfaces ; 130: 222-8, 2015 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-25910635

RESUMO

Nanofibrous 2,2,6,6-tetramethylpiperidine-1-oxyl(TEMPO)-oxidized bacterial cellulose (TOBC) was used as a dispersant of hydroxyapatite (HA) nanoparticles in aqueous solution. The surfaces of TOBC nanofibers were negatively charged after the reaction with the TEMPO/NaBr/NaClO system at pH 10 and room temperature. HA nanoparticles were simply adsorbed on the TOBC nanofibers (HA-TOBC) and dispersed well in DI water. The well-dispersed HA-TOBC colloidal solution formed a hydrogel after the addition of gelatin, followed by crosslinking with glutaraldehyde (HA-TOBC-Gel). The chemical modification of the fiber surfaces and the colloidal stability of the dispersion solution confirmed TOBC as a promising HA dispersant. Both the Young's modulus and maximum tensile stress increased as the amount of gelatin increased due to the increased crosslinking of gelatin. In addition, the well-dispersed HA produced a denser scaffold structure resulting in the increase of the Young's modulus and maximum tensile stress. The well-developed porous structures of the HA-TOBC-Gel composites were incubated with Calvarial osteoblasts. The HA-TOBC-Gel significantly improved cell proliferation as well as cell differentiation confirming the material as a potential candidate for use in bone tissue engineering scaffolds.


Assuntos
Osso e Ossos/fisiologia , Celulose/química , Durapatita/química , Nanofibras/química , Nanopartículas/química , Engenharia Tecidual/métodos , Alicerces Teciduais/química , Adsorção , Animais , Animais Recém-Nascidos , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Osso e Ossos/citologia , Osso e Ossos/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Óxidos N-Cíclicos/química , Módulo de Elasticidade , Hidrogéis/química , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Nanofibras/ultraestrutura , Nanopartículas/ultraestrutura , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Osteoblastos/fisiologia , Osteogênese/fisiologia , Porosidade , Ratos Sprague-Dawley , Resistência à Tração
16.
Carbohydr Polym ; 116: 223-8, 2015 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-25458293

RESUMO

TEMPO-oxidized bacterial cellulose (TOBC)-sodium alginate (SA) composites were prepared to improve the properties of hydrogel for cell encapsulation. TOBC fibers were obtained using a TEMPO/NaBr/NaClO system at pH 10 and room temperature. The fibrillated TOBCs mixed with SA were cross-linked in the presence of Ca(2+) solution to form hydrogel composites. The compression strength and chemical stability of the TOBC/SA composites were increased compared with the SA hydrogel, which indicated that TOBC performed an important function in enhancing the structural, mechanical and chemical stability of the composites. Cells were successfully encapsulated in the TOBC/SA composites, and the viability of cells was investigated. TOBC/SA composites can be a potential candidate for cell encapsulation engineering.


Assuntos
Alginatos/química , Celulose/química , Gluconacetobacter xylinus , Hidrogéis/química , Nanocompostos/química , Polissacarídeos Bacterianos/química , Animais , Proliferação de Células , Sobrevivência Celular , Celulose/biossíntese , Força Compressiva , Óxidos N-Cíclicos/química , Gluconacetobacter xylinus/metabolismo , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Camundongos , Microscopia/métodos , Células NIH 3T3 , Nanocompostos/ultraestrutura , Oxidantes/química , Oxirredução , Polissacarídeos Bacterianos/biossíntese , Espectroscopia de Infravermelho com Transformada de Fourier
17.
Chem Commun (Camb) ; 50(22): 2954-7, 2014 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-24503867

RESUMO

Thermoresponsive biopolymeric microstructures are prepared by exploiting the thermal phase transitions of emulsified elastin-like polypeptides (ELPs). ELP microbeads prepared below the transition temperature (Tt) have positively thermoresponsive pores. ELP microcapsules prepared above Tt have negatively thermoresponsive pores. Interestingly, the ELP microcapsules prepared at the temperature of the transition state displayed bidirectional thermoresponsive behavior.


Assuntos
Peptídeos/química , Biopolímeros/química , Elastina , Corantes Fluorescentes/química , Microscopia Confocal , Porosidade , Rodaminas/química , Temperatura
18.
Colloids Surf B Biointerfaces ; 102: 238-42, 2013 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-23000681

RESUMO

Magnetic BC was biosynthesized by culturing Gluconacetobacter xylinus in a medium containing magnetite nanoparticle (MNP) clusters. The stable dispersion of MNP clusters in an aqueous solution was achieved using amphiphilic comb-like polymer (CLP) stabilizers to disperse the MNPs. Subsequently, a conducting polymer was synthesized on the magnetic BC fibers by the chemical oxidative polymerization of aniline. The BC fiber was fully coated with polyaniline, forming hydrogen bonds. The colloidal stability of the CLP-modified MNPs was characterized by optical imaging and UV-visible spectroscopy. The chemical structure and morphology of the hybrid BC layers were observed using Fourier transform infrared spectroscopy and scanning electron microscopy. Magnetic and conductive properties were measured to confirm the immobilization of MNPs and polyaniline.


Assuntos
Compostos de Anilina/química , Bactérias/metabolismo , Celulose/química , Nanocompostos/química , Polímeros/química , Celulose/metabolismo
19.
ACS Appl Mater Interfaces ; 4(10): 5114-7, 2012 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-23046153

RESUMO

Magnetic nanoparticles (MNPs) were covalently immobilized on the surface of Acetobacter xylinus and the location of the bacteria was controlled to manipulate bacterial bioactivation. The bacteria were positioned in the middle of an incubation tube by applying an external magnetic field, and the cellulose produced at the different metabolizing locations was characterized by X-ray diffraction, electron microscopy, and differential scanning calorimetry. To the best of our knowledge, this is the first experiment in which MNPs were employed in the control of cell metabolism.


Assuntos
Celulose/biossíntese , Gluconacetobacter xylinus/metabolismo , Nanopartículas de Magnetita/química , Dióxido de Silício/química
20.
Chem Commun (Camb) ; 48(42): 5082-4, 2012 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-22344464

RESUMO

A newly prepared iminocoumarin-functionalized magnetic nanosilica (Ni@SiO(2)-1) was found to form a selective stable complex with Cu(2+) over other metal ions. Quantification of Cu(2+) ions in aqueous solution using Ni@SiO(2)-1 is demonstrated through a fluorescent demetallization ensemble process.


Assuntos
Cobre/análise , Cumarínicos/química , Magnetismo , Nanopartículas/química , Dióxido de Silício/química , Espectrometria de Fluorescência , Complexos de Coordenação/química , Cobre/isolamento & purificação , Íons/química , Nanopartículas/ultraestrutura , Níquel/química
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