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This study presents for the first time a new composite of carbon paste (CP), single-walled carbon na-notubes (SWCNTs) and Nd2O3 (NdOX). This versatile composite (NdOX-SWCNT/CPE) was applied to the oxidation of paracetamol (PCM). The newly formed surface was characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The re-sults showed greater conductivity and a higher surface area for the composite than those of the carbon paste alone. Moreover, the anodic peak currents for PCM increased from 1.6 to 3.6 mA with CPE and NdOX-SWCNT/CPE, indicating an increase of nearly 51.0％ for the anodic peak current. On the other hand, the anodic peak potentials shifted from 0.67 to 0.57 V. The detection limits were 0.05 mmol/L with NdOX-SWCNT/CPE and 0.50 mmol/L with SWCNT/CPE. The relative standard deviations (RSDs) were 1.5％(n =7). The accuracy and interference of the methods were evaluated with a urine chemistry control spiked with known quantities of PCM, uric acid, dopamine, ascorbic acid, caffeine, acetylsalicylic acid, tartrazine, sunset yellow, allure red, rutin, morin and metal ions. Finally, the novelty and usefulness of the composite were evaluated to quantify PCM in pharmaceutical dosage forms such as tablets, powders and syrups for children.
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Vertical single-walled carbon nanotubes (v-SWCNTs) array was constructed on glassy carbon electrode (GCE) by electrochemical method of electro-cyclic voltammetry (CV method).The synthesized electrode was very stable and was not easy to fall off.Via the amino groups of ethylenediamine (Ethylenediamine,EDA) and the carboxyl group of carboxylated carbon nanotubes,the SWCNTs were ordered to grow steadily on GCE(v-SWCNTs/EDA/GCE).The modified electrode was used to detect hydrochloric acid clenbuterol (CLE).The experimental results showed that the regular link of carbon nanotubes on GCE improved its utilization efficiency.The detection sensitivity of clenbuterol was 16.1 times higher than that of the bare GCE.Due to electron accelerating effect and nanometer effect of SWCNTs,the carboxyl peak current of SWCNTs was increased with the added CLE.The carboxyl peak current of SWCNTs had a good linear relationship with CLE concentration in the range of 10-120 ng/mL.The method was successfully applied to the determination of CLE in real urine samples with good recoveries.Also v-SWCNTs/EDA/GCE could be used as a new highly sensitive electrochemical sensor for CLE detection.
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Abstract This paper presents a study of the fluorescence quenching of 1-hydroxypyrene-3,6,8-trisulfonic acid (HPTS) in the presence of single-walled carbon nanotubes (SWCNT) using a fluorescence method. To investigate the quenching mechanism (dynamic or static) of HPTS, Stern-Volmer plots of single walled carbon nanotubes at different temperatures were used. The positive deviation from linearity in Stern-Volmer plots suggests that single walled carbon nanotubes follow a static quenching mechanism evidenced by the formation of a stable ground state complex. The results presented here help us to clarify the quenching mechanism in the interaction of a pyrene derived dye and carbon nanotubes. This study will open new possibilities in the use of the conjugate formed by SWCNTs and HPTS in the fabrication of a biosensor based on intracellular fluorescent probes.
Resumen Este artículo presenta el estudio de la desactivación de florescencia del ácido 1-hidroxipyreno-3,6,8-trisulfónico (HPTS) en presencia de nanotubos de carbono de pared única (SWCNT). Para investigar el mecanismo de desactivación (dinámico o estático) del HPTS se evaluaron nanotubos de carbono de pared única a diferentes temperaturas y se analizaron por medio de gráficas Stern-Volmer. La desviación positiva de la linealidad en las gráficas Stern-Volmer sugiere que los nanotubos de carbono de pared única actúan por medio de un mecanismo de desactivación estático, que se evidencia también por la formación de un complejo estable en estado fundamental. Los resultados presentados aquí nos ayudan a aclarar el mecanismo de desactivación de fluorescencia cuando tiene lugar la interacción entre un colorante derivado del pireno y nanotubos de carbono. Este estudio abre nuevas posibilidades para el uso de conjugados formados por SWCNT y HPTS en la fabricación de un biosensor basado en sondas fluorescentes intracelulares.
Resumo Este artigo apresentao estudo da diminuicao da fluorescência do ácido 1-hidroxipireno-3,6,8-trisulfônico (HPTS) em presença de nanotubos de carbono de parede simples (SWCNT). Para investigar o mecanismo da desativação (dinâmico ou estático) do HPTS se avaliaram nanotubos de parede simples em diferentes temperaturas e se analisaram por meio de gráficos Stern-Volmer. O desvio positivo de linearidade nos gráficos Stern-Volmer sugere que os nanotubos de carbono de parede simples atuam por meio de um mecanismo de desativação estática, que também se evidencia pela formação de um complexo estável fundamental. Os resultados apresentados aqui nos ajudam a aclarar o mecanismo de desativação de fluorescência quando ocorre a interação entre um corante derivado do pireno e nanotubos de carbono. Este estudo abre novas possibilidades para o uso de conjugados formados por SWCNT e HPTS na fabricação de um biosensor baseado em sondas fluorescentes intracelulares.
Subject(s)
Nanotubes, Carbon/statistics & numerical data , FluorescenceABSTRACT
Objective To investigate the method for preparing oridonin-single-walled carbon nanotubes ( ORI-SWCNTs) nanocomposite and study its adsorption kinetics. Methods ORI-SWCNTs nanocomposite was prepared by using the method of solution mixing. The synthesized ORI-SWCNTs nanocomposite was characterized by using Laser particle size analyzer, Fourier transform infrared, DSC analysis, powder X-ray diffraction and electron microscopy techniques. Results The encapsulation efficiency and loading capacity of ORI in SWCNTs-COOH nanocarrier was estimated to be about (70.23±2.1) %and (27.29±1.2) %, respectively. The Zeta potential was (-34.29±1.2) mV, partical size was about (458±18) nm. The absorption of ORI on SWCNTs-COOH could be explained by pseudo-second-order model. Conclusion The established preparation process of ORI-SWCNTs nanocomposite by solution mixing is feasible, with higher loading efficiency and encapsulate efficiency..
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Objective To investigate the method for preparing oridonin-single-walled carbon nanotubes ( ORI-SWCNTs) nanocomposite and study its adsorption kinetics. Methods ORI-SWCNTs nanocomposite was prepared by using the method of solution mixing. The synthesized ORI-SWCNTs nanocomposite was characterized by using Laser particle size analyzer, Fourier transform infrared, DSC analysis, powder X-ray diffraction and electron microscopy techniques. Results The encapsulation efficiency and loading capacity of ORI in SWCNTs-COOH nanocarrier was estimated to be about (70.23±2.1) %and (27.29±1.2) %, respectively. The Zeta potential was (-34.29±1.2) mV, partical size was about (458±18) nm. The absorption of ORI on SWCNTs-COOH could be explained by pseudo-second-order model. Conclusion The established preparation process of ORI-SWCNTs nanocomposite by solution mixing is feasible, with higher loading efficiency and encapsulate efficiency..
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Objective:To investigate the effect on the phenotype and function of CIK cells induced from splenic lymphocyte in mice treated with carboxylated single-walled carbon nanotubes.Methods:CIK cells were treated with carboxylated single-walled carbon nanotubes at different concentrations.Cell growth status was observed using inverted fluorescence microscopy.The killing effect was de-termined by MTS method.Immunophenotype was analyzed by flow cytometry.Results: With the increase of the effect target ratio,the killer rate of CIK was gradually enhanced and the optimal effect target ratio was 20:1.With the increase of the dose of carboxylated single-walled carbon nanotubes,the proportion of Treg cells decreased.When CIK cells were treated with 0.5 μg/ml carboxylated single-walled carbon nanotubes(CNTs),the proportion of CD3+CD4+and CD3+CD8+was significantly higher than that of the control group(P<0.05),and the killing effects of CIK anchieved best results to B16 cells,H22 cells and RM-1cells.Conclusion: The carboxylated single-walled carbon nanotubes enhanced the ability of CIK cells to kill tumor cells,significantly which provide has potential value in tumor drug development.
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Novel and efficient therapeutic modalities are urgently needed for cancer patients .We focused on biological therapies including oncolytic virotherapy and immune therapy against cancer .In the study of oncolytic virotherapy , we have identified the crosstalk between virus-induced mitophagy and retinoic acid inducible gene I (RIG-I)-like receptors signaling.Importantly, we find that cell necrosis rather than apoptosis ( as supposed by previous studies ) contributes dominantly to oncolysis of measles virus Edmon-strain in cancer.Furthermore, we have clarified the role of mitophagy in switching cell death from apoptosis to necrosis .These novel findings are important for further improvement of oncolyticvirotherapy .5′-Triphosphate RNA ( ppp-RNA) is a specific ligand of the pat-tern recognition receptor retinoic acid-inducible gene I ( RIG-I) .By combining immune activation and specific gene silencing , we have designed three anticancer ppp-siRNAs targeting TGF-β1 , GLS1 and VEGF , respectively , and we find that these ppp-siRNAs possess potent antitumor efficacies both in vitro and in vivo .In addition , we have also utilized nanomaterials to treat cancers .Next, we want and try to block the immune escape of cancer by targeting immune checkpoints .
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An economic and facilely prepared dopamine ( DA) sensor have been successfully fabricated by the electrodeposition of copper on single-walled carbon nanotubes ( SWNTs )/Nafion-modified glassy carbon electrode. The morphology of the material was observed by scanning electron microscopy ( SEM) and element composition of the material was investigated by energy dispersive X-ray spectroscopy ( EDX ) . Tests with various scan rates and pH conditions indicated that an adsorption-controlled process occured in the electrochemical system. The mechanism of the electrode reaction of dopamine involved a two-electron process which was accompanied by a deprotonation step. Electrochemical parameters were calculated with the electron transfer number as 2 . 67 , the charge transfer coefficients as 0 . 6 , the apparent heterogeneous electron transfer rate constant as 1. 38 s-1 . Under the optimal conditions with differential pulse voltammetric measurement, the linear equation was Ipa(μA)=-0. 054c (μmol/L)-3. 82(R2=0. 9988), with linear range of 5-100 μmol/L and detection limit of 0 . 0135 μmol/L ( S/N=3 ) . The main advantages of sensor included facile fabrication approach, high sensitivity, good stability and high reproducibility. The sensor was applied to the detection of DA in volunteer urine by differential pulse voltammetry with favorable recoveries of 96 . 5%-100 . 4% and relative standard deviations (RSDs) of 1. 2%-2. 4%.
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Objective To develop a new type of electrochemical immunosensor for the detection of ochratoxin A (OTA ) . Methods Double layers of self‐assembly immunosensor for the detection of OTA were constructed based on the composite single‐walled carbon nanotubes(SWNTs)/chitosan(CS) membrane immobilized on glassy carbon electrode(GC) .Scanning electron mi‐croscopy(SEM) ,square wave voltammetry and cyclic voltammetry were used to analyze the characterization of the sensor ,then its specificity for detection was studied .Results SWNTs/CS composit membrane could increase the sensitivity of OTA detection sig‐nificantly ,and effectively distinguish the different types of mycotoxins .Conclusion The electrochemical immunosensor developed in the study is easy to operate and could detect OTA rapidly with good specificity and low detection limit .
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Intravesical chemotherapy is an important part of the treatment for superficial bladder cancer. However, the response to it is limited and its side effects are extensive. Functional single-walled carbon nanotubes (SWNT) have shown promise for tumor-targeted accumulation and low toxicity. In the present study, we performed in vivo and in vitro investigations to determine whether SWNT-based drug delivery could induce high tumor depression in rat bladder cancer and could decrease the side effects of pirarubicin (tetrahydropyranyl-adriamycin, THP). We modified SWNT with phospholipid-branched polyethylene glycol and constructed an SWNT-THP conjugate via a cleavable ester bond. The cytotoxicity of SWNT-THP against the human bladder cancer cell line BIU-87 was evaluated in vitro. Rat bladder cancer in situ models constructed by N-methyl-N-nitrosourea intravesical installation (1 g/L, 2 mg/rat once every 2 weeks for 8 weeks) were used for in vivo evaluation of the cytotoxicity of SWNT and SWNT-THP. Specific side effects in the THP group including urinary frequency (N = 12), macroscopic hematuria (N = 1), and vomiting (N = 7) were identified; however, no side effects were observed with SWNT-THP treatment. Flow cytometry was used to assess the cytotoxicity in vitro and in vivo. Results showed that SWNT alone did not yield significant tumor depression compared to saline (1.74 ± 0.56 and 1.23 ± 0.42%) in vitro. SWNT-THP exhibited higher tumor depression than THP-saline in vitro (74.35 ± 2.56 and 51.24 ± 1.45%) and in vivo (52.46 ± 2.41 and 96.85 ± 0.85%). The present findings indicate that SWNT delivery of THP for the treatment of bladder cancer leads to minimal side effects without loss of therapeutic efficacy. Therefore, this nanotechnology may play a crucial role in the improvement of intravesical treatment of bladder cancer.
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Animals , Female , Humans , Rats , Antineoplastic Agents/administration & dosage , Doxorubicin/analogs & derivatives , Nanotubes, Carbon , Urinary Bladder Neoplasms/drug therapy , Administration, Intravesical , Antineoplastic Agents/adverse effects , Doxorubicin/administration & dosage , Doxorubicin/adverse effects , Rats, Sprague-DawleyABSTRACT
Organics of the phthalocyanine category have very good nonlinear optical properties. The single-walled carbon nanotubes were modified by using the phenoxy phthalocyanine. Characterization analysis was made by means of the transmission electron microscope (TEM), ultraviolet visible absorptive spectra, fluorescent spectra and Raman spectra. Under the TEM, it was observed that the composite looked like sugarcoated haws. By comparing the ultraviolet visible absorptive spectra before and after absorption, it was disclosed that the spectral intensity and the intensity of the peaks in the fluorescent spectra dropped remarkably. This shows that the single-walled carbon nanotubes have absorbed a large number of phenoxy phthalocyanines. Raman analysis revealed that in the Raman spectra, the position of the main peaks of the single-walled carbon nanotubes after absorption moved in the direction of long waves. The analysis suggests that the movement of the Raman spectra results from the change in the state of the single-walled carbon nanotubes before and after absorption.