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1.
Int J Biol Macromol ; 266(Pt 1): 131399, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38641504

RESUMEN

Developing an injectable hemostatic dressing with shape recovery and high blood absorption ratio for rapid hemostasis in noncompressible hemorrhage maintains a critical clinical challenge. Here, double-network cryogels based on carboxymethyl chitosan, sodium alginate, and methacrylated sodium alginate were prepared by covalent crosslinking and physical crosslinking, and named carboxymethyl chitosan/methacrylated sodium alginate (CM) cryogels. Covalent crosslinking was achieved by methacrylated sodium alginate in the freeze casting process, while physical crosslinking was realized by electrostatic interaction between the amino group of carboxymethyl chitosan and the carboxyl group of sodium alginate. CM cryogels exhibited large water swelling ratios (8167 ± 1062 %), fast blood absorption speed (2974 ± 669 % in 15 s), excellent compressive strength (over 160 kPa for CM100) and shape recovery performance. Compared with gauze and commercial gelatin sponge, better hemostatic capacities were demonstrated for CM cryogel with the minimum blood loss of 40.0 ± 8.9 mg and the lowest hemostasis time of 5.0 ± 2.0 s at hemostasis of rat liver. Made of natural polysaccharides with biocompatibility, hemocompatibility, and cytocompatibility, the CM cryogels exhibit shape recovery and high blood absorption rate, making them promising to be used as an injectable hemostatic dressing for rapid hemostasis in noncompressible hemorrhage.


Asunto(s)
Alginatos , Quitosano , Quitosano/análogos & derivados , Criogeles , Hemorragia , Hemostasis , Hemostáticos , Quitosano/química , Criogeles/química , Alginatos/química , Animales , Hemorragia/tratamiento farmacológico , Ratas , Hemostasis/efectos de los fármacos , Hemostáticos/química , Hemostáticos/farmacología , Materiales Biocompatibles/química , Humanos , Masculino
2.
Anal Chem ; 93(36): 12346-12352, 2021 09 14.
Artículo en Inglés | MEDLINE | ID: mdl-34469684

RESUMEN

Synthetic DNA walkers are artificially designed DNA self-assemblies with the capability of performing quasi-mechanical movement at the micro/nanoscale and have shown extensive promise in biosensing, intracellular imaging, and drug delivery. However, DNA walkers are usually constructed by covalently or coordinately binding DNA strands specifically to hard surfaces, thereby greatly limiting their movement efficiency. Herein, we report an intraparticle and interparticle transferable DNA walker (dynamic micelle-supported DNA walker, DM-walker) constructed by immobilizing walking tracks and walking arms onto the corona of DNA micelles according to the principle of Watson-Crick base pairing. The DNAzyme-powered walking arm can drive the intraparticle and interparticle movements of the DM-walker due to the fact that the dynamic structure of the DNA micelle helps overcome the spatial barrier between the arms and tracks in the system, resulting in high walking efficiency. Moreover, the whole DM-walker can be constructed by self-assembly, getting rid of the tedious process and low efficiency of fixing DNA strands on hard surfaces. Taking miRNA-10b as a model target, the DM-walker demonstrates high walking efficiency (reaction duration of 20 min) and high sensitivity (LOD of 87 pM). The proposed DM-walker provides an avenue to develop novel DNA walkers on dynamic interfaces and holds great potential in clinical diagnosis.


Asunto(s)
Técnicas Biosensibles , MicroARNs , ADN , Límite de Detección , Micelas
3.
J Colloid Interface Sci ; 553: 503-511, 2019 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-31229869

RESUMEN

Novel organic-inorganic composite membranes were prepared conveniently by compositing of carbon dots (CDs) possessing different hydrophilicity into the low cost blended polymers of polyvinylpyrrolidone (PVP) and polyethersulfone (PES). The hydrophilicity of the CDs arises from its surface hydrophilic groups, which could be adjusted by controlling the reaction temperature and duration time. A series of homogeneous composite membranes doping with different hydrophilic CDs of up to about 10 wt% were obtained. Comprehensive characterizations were made in order to know the influence of different hydrophilic CDs on the properties of the prepared membranes. It is found that the doped CDs could cause the change in microphase separation and benefit proton conduction of the composite membranes. The more doped CDs, the higher the conductivity. A highest conductivity of 0.086 S cm-1 was reached by a composite membrane doped with both hydrophilic and hydrophobic CDs. Moreover, the incorporated CDs brought on the changes in properties of the composite membranes including free volume, hydrophilicity, acid doping level and swelling. A single fuel cell test was made based on the CDs blended membrane and indicating its potential to be used as the membrane electrolyte in high temperature proton exchange membrane fuel cells.

4.
Mol Med Rep ; 20(2): 1306-1312, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31173216

RESUMEN

17ß­estradiol (E2) and aquaporin 2 (AQP2) are associated with endometrial receptivity, and E2 directly regulates AQP2 expression in endometrial cancer cells. The present study aimed to investigate the role of AQP2 in embryo implantation. Normal endometrial samples were collected at the Women's Hospital (Hangzhou, China) from women seeking in vitro fertilization and embryo transfer; women with endometrial abnormalities were excluded from the study. Samples were categorized into early­mid proliferative, late proliferative, early secretory, mid­secretory and late secretory phase groups, according to the menstrual cycle. The mRNA and protein expression levels of AQP2 were assessed in normal human endometrium in response to E2 via reverse transcription­quantitative polymerase chain reaction and western blotting, respectively. The effects of AQP2 on spheroid attachment were assessed using an in vitro co­culture assay with small interfering (si)RNA against AQP2. The highest expression levels of AQP2 were observed in the late proliferative and mid­secretory phases, with the lowest levels detected in the early proliferative and late secretory phases. In addition, treatment with 10­9 or 10­7 M E2 for 24 h upregulated AQP2 in the cultured endometrium. Knockdown of AQP2 by siRNA significantly decreased JAr spheroid attachment; however, this effect was significantly reversed when AQP2 siRNA­transfected cells were treated with 10­7 M E2. The results of the present study suggested that AQP2 expression levels in human endometrium may be mediated by estrogen, and low AQP2 expression levels may be a potential cause of impaired uterine receptivity.


Asunto(s)
Acuaporina 2/genética , Endometrio/metabolismo , Estradiol/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Esferoides Celulares/metabolismo , Adulto , Acuaporina 2/metabolismo , Adhesión Celular/efectos de los fármacos , Línea Celular Tumoral , Femenino , Humanos , Ciclo Menstrual/efectos de los fármacos
5.
Anal Bioanal Chem ; 411(19): 4569-4576, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-30327835

RESUMEN

A simple fluorescence biosensor is developed based on the enzyme-assisted cascade amplification strategy. The amplification system consists of a hairpin-structure DNA (H-DNA) and exonuclease III. The target DNA can hybridize with the H-DNA and initiate exonuclease III-assisted target recycling amplification to generate abundant G-rich DNA (G-DNA). One region of G-DNA is designed to possess the same sequence as target DNA. Thus, the G-DNA can also hybridize with H-DNA and initiate the digestion of H-DNA. The cascade strategy in this amplification system causes the concentration of G-DNA to grow exponentially. The fluorescence intensity of N-methylmesoporphyrin IX (NMM) is highly enhanced due to the formation of G-quadruplex configuration. Under optimal conditions, the cascade system could achieve an admirable sensitivity with a detection limit of 52 fM for HIV DNA, and guarantees a satisfactory specificity. Moreover, the cascade system could be implemented for other target DNA detections by substituting the recognition region of the H-DNA. In this way, a detection limit of 65 fM for HBV DNA could be achieved by the cascade system. The target DNA analysis in a real serum sample further indicates that this biosensor has potential for future application in clinical diagnosis. Graphical abstract A simple and label-free cascade amplification strategy is developed by exploiting hairpin DNA and EXO III for sensitive DNA detection.


Asunto(s)
ADN/análisis , Técnicas Biosensibles , Exodesoxirribonucleasas/química , Fluorescencia , Límite de Detección , Mesoporfirinas/química , Técnicas de Amplificación de Ácido Nucleico
6.
Talanta ; 188: 685-690, 2018 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-30029432

RESUMEN

Taking advantage of the homogeneous and heterogeneous electrochemical biosensors, a simple, sensitive, and selective electrochemical biosensor is constructed by combining entropy-driven amplification (EDA) with DNA walker. This electrochemical biosensor realizes the biorecognition and EDA operation in homogeneous solution, which is beneficial to improve the recognition and amplification efficiency. A two-leg DNA walker generated by EDA can walk on the surface of gold electrode for cleaving the immobilized substrate DNA and releasing the electroactive labels, giving rise to a significant decrease of the electrochemical signal. The immobilization of the electroactive labels ensures the reproducibility and reliability of the biosensor. The present cascade amplification assay can be applied to detect target DNA with a detection limit of 0.29 fM, and base mutations can be easily distinguished. Moreover, the proposed electrochemical biosensor shows a satisfactory performance for the detection of target DNA in human serum. Thus, the novel electrochemical biosensor holds promising potential for a future application in disease diagnosis.


Asunto(s)
Técnicas Biosensibles/métodos , ADN Catalítico/química , ADN/sangre , Técnicas Electroquímicas/métodos , Ácidos Nucleicos Inmovilizados/sangre , Nanoestructuras/química , ADN/metabolismo , Electrodos , Oro/química , Humanos , Plomo/química , Límite de Detección , Azul de Metileno/química , Técnicas de Amplificación de Ácido Nucleico/métodos , Hibridación de Ácido Nucleico , Reproducibilidad de los Resultados
7.
Sci Rep ; 8(1): 3985, 2018 03 05.
Artículo en Inglés | MEDLINE | ID: mdl-29507303

RESUMEN

Twin pregnancies have a higher prevalence of intrahepatic cholestasis of pregnancy (ICP) than single pregnancies. It is unknown whether in vitro fertilization-embryo transfer (IVF-ET) influences the fetal outcomes in twin pregnancies complicated by ICP. This study aimed to explore the impact of IVF-ET on the perinatal outcomes of ICP in twin pregnancy. Clinical data from 142 twin pregnant women complicated with ICP were retrospectively analyzed, including 51 patients who conceived through IVF-ET (IVF group) and 91 patients with spontaneous conception (SC group). Several biochemical indicators and perinatal outcomes were analyzed. Compared to the SC group, the IVF group had a higher incidence of early-onset ICP (P = 0.015) and more frequent clinical symptoms (P = 0.020), including skin pruritus, skin scratch, and jaundice. Furthermore, the IVF group had higher rates of neonatal asphyxia (IVF vs. SC, 9.80% vs. 1.10%, P = 0.023) and premature delivery (IVF vs. SC, 96.08% vs. 83.52%, P = 0.027) compared to the SC group. The IVF-conceived twin pregnancy group had a higher risk of early-onset ICP and suffered from clinical symptoms and poor perinatal outcomes.


Asunto(s)
Colestasis Intrahepática/complicaciones , Transferencia de Embrión , Fertilización In Vitro , Embarazo Gemelar , Adulto , Transferencia de Embrión/métodos , Femenino , Fertilización , Fertilización In Vitro/métodos , Humanos , Embarazo , Complicaciones del Embarazo , Resultado del Embarazo , Estudios Retrospectivos
8.
Biosens Bioelectron ; 105: 159-165, 2018 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-29412940

RESUMEN

DNA can be modified to function as a scaffold for the construction of a DNA nanomachine, which can then be used in analytical applications if the DNA nanomachine can be triggered by the presence of a diagnostic DNA or some other analyte. We herein propose a novel and powerful DNA nanomachine that can detect DNA via combining the tandem strand displacement reactions and a DNA walker. Three different DNA sensing platforms are described, where the whole DNA machine was constructed on a gold electrode (GE). This cascade multiple amplification strategy exhibited an excellent sensitivity. Under optimal conditions, the electrochemical sensor could achieve a detection limit of 36 fM with a linear range from 50 to 500 fM. In particular, the electrochemical sensor could easily distinguish the base mutations. More interestingly, the DNA nanomachine could be used to construct analog AND and OR logic gates. We demonstrate that electrochemical signals generated from the different input combinations can be used to distinguish multiple target DNAs. The practical applicability of the present biosensor is demonstrated by the detection of target DNA in human serum with satisfactory results, which holds great potential for a future application in clinical diagnosis.


Asunto(s)
Técnicas Biosensibles/métodos , ADN/análisis , Disparidad de Par Base , ADN/sangre , ADN/genética , Técnicas Electroquímicas/métodos , Humanos , Límite de Detección , Técnicas de Amplificación de Ácido Nucleico/métodos
9.
Mol Med Rep ; 16(3): 3503-3509, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-28713996

RESUMEN

The pathogenesis of stress urinary incontinence (SUI) is unclear. Aquaporins (AQPs) are a family of transmembrane proteins that transport water and small solutes, including glycerol, across cell membranes. AQPs have been demonstrated to serve a role in skin hydration, cellular proliferation, migration, immunity, wound healing and vascular remodeling in multiple organs. Furthermore, studies have confirmed that abnormal synthesis and degradation of collagens in extracellular matrix (ECM) remodeling contributes to SUI, by altering normal tissue architecture and mechanical properties. The authors previously demonstrated that AQP2 expressed in the human endometrium varies during the menstrual cycle. However, it is unknown whether AQP2 serves a role in the pathogenesis of SUI in the urethral supporting tissue. In the present study, AQP2 location and expression was examined in the anterior vaginal wall, and investigated the association between AQP2 and collagen I/III in female SUI. Western blotting, immunohistochemistry and immunofluorescence were used to measure AQP2 expression levels, and to reveal the location of AQP2 in the anterior vaginal wall, as well as fibroblasts in SUI and non­SUI. The association between AQP2 and collagen I/III was subsequently investigated by AQP2­small interfering RNA knockdown and overexpression 2 in fibroblasts. AQP2 expression in the anterior vaginal wall was significantly increased in women without SUI compared with those with SUI (P<0.05). Downregulation of AQP2 significantly decreased the mRNA and protein expression of collagen I/III, while AQP2 overexpression significantly increased the mRNA and protein expression of collagen I/III in fibroblasts (P<0.05). AQP2 was demonstrated to be expressed in the anterior vaginal wall and fibroblasts, and to regulate the expression level of collagen I/III in the anterior vaginal wall and fibroblasts, suggesting that AQP2 is associated with the pathogenesis of female SUI through collagen metabolism during ECM remodeling.


Asunto(s)
Acuaporina 2/metabolismo , Regulación hacia Abajo , Incontinencia Urinaria de Esfuerzo/etiología , Incontinencia Urinaria de Esfuerzo/metabolismo , Vagina/metabolismo , Vagina/patología , Western Blotting , Colágeno Tipo I/metabolismo , Colágeno Tipo III/metabolismo , Matriz Extracelular/metabolismo , Femenino , Fibroblastos/metabolismo , Fibroblastos/patología , Técnicas de Silenciamiento del Gen , Humanos , Persona de Mediana Edad , Incontinencia Urinaria de Esfuerzo/patología
10.
J Colloid Interface Sci ; 497: 333-342, 2017 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-28301829

RESUMEN

Two N3-substituted imidazoles 1,2-dimethylimidazole and 1-butyl-2-methylimidazole were chosen to functionalize poly(aryl ether ketone), respectively. The generated imidazolium cations could electrostatically react with sulfonate ions of the sulfonated poly(ether ether ketone) forming the ionic crosslinking structure of the membranes. The changes in crosslinking degree and the alkyl chain-length on N3 site of the imidazoliums could highly affect the properties of the anion exchange membranes (AEMs). The AEMs functionalized by 1-butyl-2-methylimidazole exhibited superior properties compared to those functionalized by 1,2-dimethylimidazole according to the tolerance tests of the AEMs towards hot alkaline solutions. After exposed to 1M KOH at 80°C for 200h, the 1-butyl-2-methylimidazole modified AEMs maintained the ion exchange capacity of above 85%, the conductivity of about 70%, and the tensile stress at break of around 80%, respectively. The hydrophile-lipophile balance of the polymer membranes was calculated and proposed to better understand the correlation between structures and properties of the AEMs. The degradation of the imidazolium functional groups of the AEMs under the attack of hydroxide ions was evidenced by FT-IR analysis.

11.
Talanta ; 166: 87-92, 2017 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-28213264

RESUMEN

Simple, rapid, sensitive, and specific detection of cancer cells plays a pivotal role in the diagnosis and prognosis of cancer. A sandwich electrochemical biosensor was developed based on polyadenine (polydA)-aptamer modified gold electrode (GE) and polydA-aptamer functionalized gold nanoparticles/graphene oxide (AuNPs/GO) hybrid for the label-free and selective detection of breast cancer cells (MCF-7) via a differential pulse voltammetry (DPV) technique. Due to the intrinsic affinity between multiple consecutive adenines of polydA sequences and gold, polydA modified aptamer instead of thiol terminated aptamer was immobilized on the surface of GE and AuNPs/GO. The label-free MCF-7 cells could be recognized by polydA-aptamer and self-assembled onto the surface of GE. The polydA-aptamer functionalized AuNPs/GO hybrid could further bind to MCF-7 cells to form a sandwich sensing system. Characterization of the surface modified GE was carried out by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) using Fe(CN)63-/4- as a redox probe. Under the optimized experimental conditions, a detection limit of 8 cellsmL-1 (3σ/slope) was obtained for MCF-7 cells by the present electrochemical biosensor, along with a linear range of 10-105 cellsmL-1. By virtue of excellent sensitivity, specificity and repeatability, the present electrochemical biosensor provides a potential application in point-of-care cancer diagnosis.


Asunto(s)
Aptámeros de Nucleótidos/química , Técnicas Biosensibles/métodos , Neoplasias de la Mama/diagnóstico , Separación Celular/métodos , Poli A/química , Técnicas Biosensibles/instrumentación , Separación Celular/instrumentación , Electroquímica , Electrodos , Oro/química , Grafito/química , Humanos , Límite de Detección , Nanopartículas del Metal/química , Óxidos/química
12.
Anal Bioanal Chem ; 409(7): 1797-1803, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-27981340

RESUMEN

To specifically and sensitively identify bisphenol A (BPA) with a simple and rapid method is very important for food safety. Using an anti-BPA aptamer and Mo2C nanotubes, we developed a label-free and low-background signal biosensor for BPA detection. The anti-BPA aptamer drastically increased the fluorescence signal of N-methylmesoporphyrin IX under an assistance of Help-DNA. Additionally, BPA can interact with the anti-BPA aptamer and switch its conformation to prevent the formation of a G-quadruplex, resulting in fluorescence quenching. Simultaneously, Mo2C nanotubes can reduce the background signals due to the adsorption of Help-DNA on their surface. This method shows a linear range of 2-20 nM with a detection limit of 2 nM for detecting BPA. This label-free BPA aptasensor with low background signal is inexpensive, easy to use, and can be applied to determine BPA in real water samples. Graphical Abstract A low-background and label-free biosensor was designed based on Mo2C nanotubes and aptamer for BPA detection.


Asunto(s)
Compuestos de Bencidrilo/análisis , Molibdeno/química , Nanotubos/química , Fenoles/análisis , Límite de Detección , Microscopía Electrónica de Rastreo , Microscopía Electrónica de Transmisión
13.
Sci Rep ; 6: 34810, 2016 10 07.
Artículo en Inglés | MEDLINE | ID: mdl-27713517

RESUMEN

A series of complex logic gates were constructed based on graphene oxide and DNA-templated silver nanoclusters to perform both arithmetic and nonarithmetic functions. For the purpose of satisfying the requirements of progressive computational complexity and cost-effectiveness, a label-free and universal platform was developed by integration of various functions, including half adder, half subtractor, multiplexer and demultiplexer. The label-free system avoided laborious modification of biomolecules. The designed DNA-based logic gates can be implemented with readout of near-infrared fluorescence, and exhibit great potential applications in the field of bioimaging as well as disease diagnosis.


Asunto(s)
Computadores Moleculares , ADN , Conceptos Matemáticos , ADN/química , Grafito/química , Lógica , Nanopartículas del Metal , Óxidos/química , Plata/química
14.
Nanotechnology ; 27(35): 355102, 2016 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-27458235

RESUMEN

This work describes a novel and general redox-responsive controlled drug delivery-release nanocarrier with mesoporous carbon nanoparticles (MCNs) gated by customized fluorescent carbon dots (CDs). The modification of MCNs with a disulfide unit enables the system to be sensitive to intracellular glutathione (GSH). The CDs anchoring onto the surface of the MCNs via an electrostatic interaction block the mesopores and thus prevent the leakage of doxorubicin (DOX) loaded inside the channel of the MCNs. Upon the addition of GSH at the physiological environment, the integrity of the system is disrupted due to the dissociation of the disulfide bond; meanwhile stripping the CDs opens the gate and thus triggers the rapid release of the encapsulated DOX. The fluorescence of the CDs is quenched/'turned off' when linking to the MCNs, while it is restored/'turned on' when detaching the CDs from the surface of the MCNs. Thus the fluorescent CDs serve as both a controllable drug release gatekeeper and a fluorescent probe for the visualization of the drug delivery process. By combining these inherent capabilities, the present drug delivery system may be a promising route for designing custom-made visual controlled-release nanodevices specifically governed by in situ stimulus in the cells.


Asunto(s)
Sistemas de Liberación de Medicamentos , Carbono , Doxorrubicina , Portadores de Fármacos , Colorantes Fluorescentes , Glutatión , Nanopartículas , Porosidad , Dióxido de Silicio
15.
J Mater Chem B ; 4(30): 5178-5184, 2016 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-32263516

RESUMEN

A pH and redox responsive bi-trigger continuous drug release nanocarrier is developed by capping mesoporous carbon nanoparticles (MCNs) with polyacrylic acid (PAA), termed as PAA-ss-MCN. The nanocarrier contains disulfide bond units and exhibits pH responsive behavior. It provides promising potential for drug loading due to the internal uniform channels and large surface area of MCNs. PAA grafted on the exterior surface of MCNs acts as a gating layer, generating a novel nano-container and a pH-responsive intelligent nanovalve. By loading doxorubicin (DOX) in PAA-ss-MCN, its sequential release is achieved via two approaches: (1) the intracellular acidic environment induces partial release from the surface of the PAA gating layer, (2) release of the drug sealed in nanochannels via disruption of the integrity of the nanocarrier by glutathione (GSH) caused dissociation of disulfide bonds in the physiological environment. As a result, release of 62% loaded drug is readily achieved. After culturing with HeLa cells, DOX transports into the cell interior and therein exhibits pH- and GSH-sensitive release. As most tumor sites exhibit more acidic environments or high redox potential, the pH- and GSH-sensitive releasing capability of PAA-ss-MCN is particularly useful for controllable drug delivery by taking advantage of the inherent characteristics of tumor cells.

16.
Anal Bioanal Chem ; 405(15): 5353-8, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23515609

RESUMEN

Ionic liquids have attracted much attention in the analysis of a variety of species. The functional groups in ionic liquids can result in highly efficient separation and enrichment and, because of their typical lack of volatility, they are environmentally benign. We grafted imidazole cations onto the surface of chloromethyl polystyrene, denoted PS-CH2-[MIM](+)Cl(-), and this modified polymer was used to selectively extract the protein hemoglobin (Hb). The prepared extractant PS-CH2-[MIM](+)Cl(-), containing 2 mmol immobilized imidazole groups per gram polymer, was characterized by FT-IR, surface charge analysis, and elemental analysis. The adsorption efficiency was 91%. The adsorption capacity of the PS-CH2-[MIM](+)Cl(-) for Hb was 23.6 µg mg(-1), and 80% of the retained Hb could be readily recovered by use of 0.5% (m/v) aqueous sodium dodecyl sulfate (SDS) solution as eluate. The activity of the eluted Hb was approximately 90%. The prepared imidazole-containing solid phase polymer was used for direct adsorption of Hb without use of any other solid matrix as support of the ionic liquid. The material was used in practice to isolate Hb from human whole blood.


Asunto(s)
Fraccionamiento Químico/métodos , Hemoglobinas/química , Imidazoles/química , Poliestirenos/química , Adsorción , Propiedades de Superficie
17.
ChemSusChem ; 6(2): 275-82, 2013 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-23303655

RESUMEN

Covalently cross-linked polymer membranes were fabricated from poly(aryl sulfone benzimidazole) (SO(2)PBI) and poly(vinylbenzyl chloride) (PVBCl) as electrolytes for high-temperature proton-exchange-membrane fuel cells. The cross-linking imparted organo insolubility and chemical stability against radical attack to the otherwise flexible SO(2)PBI membranes. Steady phosphoric acid doping of the cross-linked membranes was achieved at elevated temperatures with little swelling. The acid-doped membranes exhibited increased mechanical strength compared to both pristine SO(2)PBI and poly[2,2'-(m-phenylene)-5,5'-bibenzimidazole] (mPBI). The superior characteristics of the cross-linked SO(2)PBI membranes allowed higher acid doping levels and, therefore, higher proton conductivity. Fuel-cell tests with the cross-linked membranes demonstrated a high open circuit voltage and improved power performance and durability.


Asunto(s)
Bencimidazoles/química , Fuentes de Energía Bioeléctrica , Membranas Artificiales , Polivinilos/química , Sulfonas/química , Acetamidas/química , Conductividad Eléctrica , Fenómenos Mecánicos , Solubilidad , Temperatura
18.
Talanta ; 88: 352-7, 2012 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-22265510

RESUMEN

A miniature analytical system based on a lab-on-valve platform is developed for trace metal analysis by bead injection spectroscopy. A multipurpose flow cell integrated into a lab-on-valve is furnished with two pieces of fiber optics to communicate with light source and charge coupled device (CCD) spectrometer, respectively, in order to monitor real-time absorbance of the samples. Micro-beads loaded with chromogenic reagent are packed into the multipurpose flow cell to form a renewable microcolumn for solid phase extraction by bead injection. When the sample solution flows through the microcolumn, the target analyte will be captured on the surface of beads and detected directly by the CCD spectrometer without elution. The beads are automatically discarded from the multipurpose flow cell after each analytical cycle. This analytical system was employed to determine trace copper by loading of a chromogenic reagent 2-carboxy-2'-hydroxy-5'-sulfoformazylbenzene (zincon) on the beads of an anion exchanger (Sephadex QAE A-25). With a sample volume of 2.5mL, a detection limit of 3µgL(-1) and a linear range of 10-100µgL(-1) were obtained for copper, along with a RSD value of 2.5% (at the 50µgL(-1) level). The accuracy and practical applicability of the proposed system were validated by analysing certified reference materials, i.e., GBW10010, GBW09101, GBW08608, and further demonstrated by spiking recovery of copper in a water sample.


Asunto(s)
Cobre/análisis , Oligoelementos/análisis , Dextranos , Análisis de Inyección de Flujo/instrumentación , Análisis de Inyección de Flujo/métodos , Formazáns/química , Agua Dulce/química , Cabello/química , Humanos , Concentración de Iones de Hidrógeno , Límite de Detección , Microesferas , Fibras Ópticas , Oryza/química , Estándares de Referencia , Extracción en Fase Sólida/métodos , Análisis Espectral/instrumentación , Análisis Espectral/métodos , Electricidad Estática
19.
J Clin Endocrinol Metab ; 96(9): E1399-408, 2011 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-21715543

RESUMEN

BACKGROUND: Accumulating evidence suggests that aquaporins (AQP) can facilitate cell migration, invasion, and proliferation in tumor development in addition to water transport. OBJECTIVE: The aim of this study was to examine AQP2 expression in the endometrial tissues from patients with endometrial carcinoma (EC) and determine the roles and mechanisms of AQP2 in estrogen-related cell migration, invasion, adhesion, and proliferation of Ishikawa (IK) cells. APPROACH: AQP2 expression levels were measured in human endometrial cells and estradiol (E(2))-treated IK cells, and the estrogen-response element was identified. After blocking down and up-regulating the endogenous expression of AQP2 in IK cells, cell morphology, capacity for invasion, migration and adhesion, and expression markers of membrane/cytoskeleton were analyzed. RESULTS: AQP2 was expressed in endometrial tissues from patients with EC and endometriosis, both of which are estrogen-dependent diseases. In IK cells, E(2) dose-dependently increased AQP2 expression, which was blocked by the estrogen receptor inhibitor ICI182780. An estrogen-response element was identified in the AQP2 promoter. E(2) significantly increased the migration, invasion, adhesion, and proliferation of IK cells. AQP2 knockdown attenuated E(2)-enhanced migration, invasion, and adhesion. AQP2 knockdown reduced not only the E(2)-enhanced expression of F-actin and annexin-2 but also the E(2)-induced alteration of cell morphology. Moreover, higher expression levels of F-actin and annexin-2 were detected in the endometrial tissues from patients with EC. CONCLUSIONS: AQP2 mediates E(2)-enhanced migration, invasion, and adhesion through alteration of F-actin and annexin-2 expression and reorganization of F-actin, and inhibition of AQP may be a potential method for antitumor therapy.


Asunto(s)
Acuaporina 2/genética , Carcinoma/genética , Movimiento Celular/genética , Neoplasias Endometriales/genética , Estradiol/genética , Estrógenos/genética , Elementos de Respuesta/genética , Actinas/genética , Actinas/metabolismo , Adulto , Anciano , Anexina A2/genética , Anexina A2/metabolismo , Acuaporina 2/metabolismo , Carcinoma/metabolismo , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Neoplasias Endometriales/metabolismo , Estradiol/metabolismo , Estradiol/farmacología , Estrógenos/metabolismo , Estrógenos/farmacología , Femenino , Humanos , Persona de Mediana Edad , Elementos de Respuesta/efectos de los fármacos
20.
J Colloid Interface Sci ; 361(1): 219-25, 2011 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-21658699

RESUMEN

Anion exchange membranes with semi-interpenetrating polymer network (semi-IPN) were prepared based on quaternized chitosan (QCS) and polystyrene (PS). The PS was synthesized by polymerization of styrene monomers in the emulsion of the QCS in an acetic acid aqueous solution under nitrogen atmosphere at elevated temperatures. The semi-IPN system was formed by post-cross-linking of the QCS. A hydroxyl ionic conductivity of 2.80×10(-2) S cm(-1) at 80°C and a tensile stress at break of 20.0 MPa at room temperature were reached, respectively, by the semi-IPN membrane containing 21 wt.% of the PS. The durability of the semi-IPN membrane in alkaline solutions was tested by monitoring the variation of the conductivity and the mechanical strength. The degradation of the conductivity at 80°C was about 5% by immersing the membrane in a 1 mol L(-1) KOH solution at room temperature for 72 h and at 60°C for 50 h, respectively. The tensile stress at break at room temperature could maintain about 20.0 MPa for the membrane soaking in a 10 mol L(-1) KOH solution at ambient temperature for more than 70 h. The water swelling of the semi-IPN membranes was discussed based on the stress relaxation model of polymer chains, and it obeyed the Schott's second-order swelling kinetics.


Asunto(s)
Aniones/química , Quitosano/química , Membranas Artificiales , Poliestirenos/química , Quitosano/síntesis química , Intercambio Iónico , Polimerizacion , Poliestirenos/síntesis química , Temperatura , Resistencia a la Tracción , Agua/química
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