查找使用阿拉丁产品的科研文献

Porous architectures based on halloysite nanotubes as photothermal materials for efficient solar steam generation

Miaomiao Xia,Lihua Chen,Chuantao Zhang,Qi-Meige Hasi,Zhenhua Li,Hailing Li

Solar steam generation assisted by photothermal materials has attracted extensive attention due to its advantages of excellent evaporation rate and high photothermal conversion efficiency. In this work, we report a simple method by employment of halloysite (Hal) nanotubes (HNT) and graphene oxide (GO) as raw materials to produce efficient solar photothermal materials (named as GO-HNT). The as-prepared GO-HNT has rich porosity, excellent 90% light absorption and good thermal insulation performance (thermal conductivity 0.162 W m −1  K −1 ). Based on these characteristics, GO-HNT can be used as a promising solar receiver. Correspondingly, the solar energy conversion efficiency of the GO-HNT solar receiver was measured to be 83.67%, 77.17% and 77.05% respectively under 1 sun, 2 sun and 3 sun irradiations. As a 1D nanocrystalline clay mineral, HNT have great advantages of environmentally friendly, cost-efficient and commercial availability with abundant reserves. In combination with its simple and scalable manufacture method, this GO-HNT-based solar receiver may hold great potentials for a broad range of applications, such as seawater desalination, distillation, sterilization, sewage treatment, etc.

Functionalization of Halloysite Nanotubes via Grafting of Dendrimer for Efficient Intracellular Delivery of siRNA

Zheru Long,Yan-Ping Wu,Hua-Ying Gao,Yi-Fang Li,Rong-Rong He,Mingxian Liu

Here, polyamidoamine grafted halloysite nanotubes (PAMAM-g-HNTs) were synthesized for loading of siRNA in order to intracellular delivery of siRNA and treat of breast cancer via gene therapy. The successful grafting of PAMAM on HNTs was confirmed by various analytical methods. The size, zeta potential, and grafting ratio of PAMAM-g-HNTs is ∼206.2 nm, +19.8 mV, and 3.04%, respectively. PAMAM-g-HNTs showed good cytocompatibility toward HUVECs (84.7%) and MCF-7 cells (82.3%) even at high concentration of 100 μg/mL. PAMAM-g-HNTs/siRNA exhibited enhanced cellular uptake efficiency of 94.3% compared with Lipofectamine 2000 (Lipo2000)/siRNA (83.6%). PAMAM-g-HNTs/small interfering RNA-vascular endothelial growth factor (siVEGF) led to 78.0% knockdown of cellular VEGF mRNA and induced 33.6% apoptosis in the MCF-7 cells, which is also much higher than that of Lipo2000/siVEGF. In vivo anti-cancer results demonstrated that PAMAM-g-HNTs/siVEGF treated 4T1-bearing mice showed enhanced anti-cancer efficacy than Lipo2000/siVEGF group. Also, the nanocarrier system showed negligible toxic effects toward the major organs of mice. In vivo fluorescence imaging studies showed that there is a slight decrease in the fluorescence signal of PAMAM-g-HNTs/cy5-siVEGF after 72 h post-injection. Therefore, PAMAM-g-HNTs show promising application as novel nanovectors for siRNA delivery and gene therapy of cancer.

Enhanced Therapeutic Efficacy of Doxorubicin for Breast Cancer Using Chitosan Oligosaccharide-Modified Halloysite Nanotubes

Jing Yang,Yanping Wu,Yan Shen,Changren Zhou,Yi-Fang Li,Rong-Rong He,Mingxian Liu

Halloysite nanotubes (HNTs) are natural aluminosilicates with unique hollow lumen structure, also having high specific area, good biocompatibility, nontoxicity, and low price. Here, we designed a chitosan oligosaccharide-grafted HNTs (HNTs-g-COS) as a doxorubicin (DOX) carrier for treating breast cancer both in vitro and in vivo. The structure of HNTs-g-COS was first characterized by various methods. HNTs-g-COS showed positively charged surface and improved hemocompatibility. DOX-loaded HNTs-g-COS (DOX@HNTs-g-COS) released in cell lysate in a controlled manner. The IC50 value of DOX@HNTs-g-COS toward MCF-7 cells was 1.17 μg mL–1, while it was 2.43 μg mL–1 for free DOX. DOX@HNTs-g-COS increased the apoptosis effects of MCF-7 cells as shown in flow cytometry results. Also, reactive oxygen species of cells induced by DOX@HNTs-g-COS were drug-dose-dependent. DOX@HNTs-g-COS could enter the MCF-7 cells and induce mitochondrial damage as well as attack the nuclei. The in vivo antitumor effect of DOX@HNTs-g-COS was investigated in 4T1-bearing mice. The tumor-inhibition ratio of DOX@HNTs-g-COS was 83.5%, while it was 46.1% for free DOX. All mice treated with DOX@HNTs-g-COS survived over 60 days. DOX@HNTs-g-COS showed fewer ruptured cardiomyocytes and no obvious systemic toxicity. Therefore, the rational designed HNTs nanocarrier for chemotherapy drug showed promising applications in tumor treatment.

Preparation and characterization of novel modified halloysite-Fe3O4-Ag/polyurea nanocomposites with antibacterial property

Heqing Fu,Lingyuan Liao,Xiaoya Li,Weifeng Chen

First, modified halloysite-Fe3O4 nanotubes (mHNT-Fe3O4) were synthesized. Second, mHNT-Fe3O4-Ag was synthesized by reduction process. Third, mHNT-Fe3O4-Ag was covalently incorporated into the polyurea (PUA) matrix and the mHNT-Fe3O4-Ag/PUA nanocomposites were prepared. The mHNT-Fe3O4-Ag was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, UV-vis absorption spectra, transmission electron microscopy, thermogravimetric analysis, and dynamic mechanical analysis. The experimental results shown that thermal stability, tensile strength, and storage modulus of nanocomposites were improved with the increasing of the content of mHNT-Fe3O4-Ag. Meanwhile, mHNT-Fe3O4-Ag/PUA nanocomposites had excellent magnetic properties and good antibacterial property.

Folic acid-conjugated chitosan oligosaccharide-magnetic halloysite nanotubes as a delivery system for camptothecin

Pierre Dramou,Meriem Fizir,Abdoh Taleb,Asma Itatahine,Nasiru Sintali Dahiru,Yamina Ait Mehdi,Liu Wei,Jingyi Zhang,Hua He

In this research, to achieve enhanced intracellular uptake of anticancer drug carriers for efficient chemotherapy, folic acid conjugated chitosan oligosaccharides assembled magnetic halloysite nanotubes (FA-COS/MHNTs) have been tailored as multitask drug delivery system towards camptothecin (CPT). Besides magnetic targeting, the nanocomposites have been reacted with folate complex in order to selectively target cancer cells over expressing the folic acid receptor. HNTs showed to have a high storage capacity of CPT. In vitro, the release results indicated that CPT outflow from the nanocarriers at pH 5 was much greater than that at both pH 6.8 and 7.4. MTT assays showed that the CPT-loaded nanocarriers exhibited stronger cell growth inhibitory against colon cancer cell. Furthermore, nanocarriers gained specificity to target cancer cells because of the enhanced cell uptake mediated by FA moiety and presence of COS. Therefore, the rational designed HNTs nanocarrier for chemotherapy drug showed great potential as tumor-targeted drug delivery carrier.

Fabrication of high performance superhydrophobic coatings by spray-coating of polysiloxane modified halloysite nanotubes

Keying Feng,Guang-Yu Hung,Jiashang Liu,Mingqing Li,Changren Zhou,Mingxian Liu

Superhydrophobic coatings with high water contact angles, ultralow sliding angles, excellent stability, oil/water separation, and self-cleaning functions were fabricated by spray-coating the suspensions of polysiloxane modified halloysite nanotubes (POS@HNTs) onto various substrates. The hydrophobic treatment of HNTs was performed by hydrolytic co-condensation of n -hexadecyltriethoxylsilane and tetraethoxysilane on the surfaces of the HNTs. A thick POS layer is located on the surfaces of the HNTs, which makes HNTs hydrophobic. The POS@HNTs were characterized using scanning electron microscopy, transmission electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction analysis, X-ray photoelectron spectroscopy and thermogravimetric analysis. The effects of the ratio of silane and HNTs on the transparency, morphology, and wettability of the coatings were investigated. The transparency of the coating decreases with the increase in the silane loading. The water contact angles of the POS@HNTs coating increase with the increase in the silane loading, but the water sliding angles of the coatings are nearly independent on their ratio. The stability, oil/water separation, and self-healing capability of the coatings were also studied. The coatings on different substrates show high contact angle towards different liquid, e.g. 1 M HCl, 1 M NaOH, tea, and milk. Also, the POS@HNTs coated meshes can efficiently separate oils from water with high separation efficiency. In addition, the POS@HNTs coated gloves show a self-cleaning effect. All these results suggest that the POS@HNTs exhibit great potential for their application in waterproof materials, self-cleaning coating, and oil/water separation devices.

Storing solar energy within Ag-Paraffin@Halloysite microspheres as a novel self-heating catalyst

Yafei Zhao,Weixiao Kong,Zunlong Jin,Ye Fu,Wencai Wang,Yatao Zhang,Jindun Liu,Bing Zhang

With the rapid depletion of fossil fuels and the associated environmental issues, solar energy is identified as one of the most promising pollution-free and renewable resource. Herein, we prepared a novel Ag-Paraffin@Halloysite microsphere with the integrated abilities of storing solar energy and catalytic function by self-assembly method. The results show that Ag-Paraffin@Halloysite microsphere has a core-shell structure with paraffin as core and halloysite as shell, and Ag nanoparticles are dispersed uniformly on the surface of the microspheres. The high thermal storage capability, encapsulation ratio and encapsulation efficiency of Ag-Paraffin@Halloysite indicate that it can be used as an ideal heat storage material. Compared with pure paraffin, Ag-Paraffin@Halloysite has higher thermal conductivity, excellent thermal storage capacity, and faster transient thermal response. After heat storage, Ag-Paraffin@Halloysite shows much better catalytic activity (95.3% of conversion in 6 min) compared with the one without heat storage (71.1% of conversion in 6 min) for catalytic reduction of 4-nitrophenol. This result suggests its potential to be used as a self-heating catalyst for storing/releasing thermal energy during catalytic reactions. This work may offer a general and innovative approach to couple phase change materials with catalyst and open up a new avenue for utilization of solar energy in the fields of chemistry and chemical engineering.

Enhanced visible-light photocatalytic performance of electrospun carbon-doped TiO2/halloysite nanotube hybrid nanofibers

Ling Jiang,Yunpeng Huang,Tianxi Liu

In this work, the effects of halloysite nanotubes (HNTs) on the visible-light photocatalytic ability of electrospun carbon doped TiO 2 /HNT (C TH) nanofibers have been explored. Structural and morphological investigations demonstrate that incorporation of HNTs into anatase C TH hybrid nanofibers was easily achieved by using sol–gel processing combined with electrospinning approach, thus HNTs could be uniformly embedded in the electrospun nanofibers. The visible-light photocatalytic efficiency of C TH hybrid on the degradation of methyl blue (MB) was greatly enhanced with the combination of moderate amount of HNTs (8%), which was 23 times higher than that of commercial anatase TiO 2 . Mechanism of the enhancing effect of HNTs has been explored by analyzing the dual-effect of adsorption and photocatalysis in various amounts of HNTs incorporated C TiO 2 nanofibers. With nanotubular structure and considerable adsorption ability, incorporated HNTs functioned as porogen agent in C TH nanofibers. This simple incorporation approach increases the specific surface areas of nanofibers, which improves the mass transport of reactant into the nanofibers and the adsorption of visible-light by scattering, meanwhile may suppress the charge recombination and enhance photoinduced charge separation, thus efficiently enhancing visible-light photocatalytic performance of the C TH hybrid nanofibers.

Novel self-healing anticorrosion coating based on L-valine and MBT-loaded halloysite nanotubes

Dong Chundong,Zhang Manxin,Xiang Tengfei,Yang Ling,Chan Wenming,Li Cheng

This work creatively utilized the pH-dependent electrostatic interactions between L-valine (L-Val) and halloysite nanotubes (HNTs) to fabricate pH-responsive anticorrosion materials and compared with 2-mercaptobenzothiazole (MBT)-loaded HNTs, which were assembled via layer-by-layer (LbL) self-assembly. These two methods can achieve controlled release of inhibitors and self-healing performance. However, the loading capacity of L-Val-loaded HNTs is higher than that of MBT’s. There are 12 and 7 wt%, respectively. The pH-responsive release property was systematically evaluated by ultraviolet–visible (UV/Vis) spectrophotometry measurement. It demonstrates that 98% of adsorbed L-Val molecules released from HNTs within 300 min at pH 10 while the loaded MBT needs 120 h to achieve the equal ratio. Moreover, the difference of the release rate has a significant impact on the artificial crossed scratch experiment and shows a great performance gap in photographs. By comparing electrochemical impedance spectroscopy (EIS) data of three epoxy coatings, it can be seen that the epoxy coating, which was mixed with L-Val-loaded HNTs, shows a better anticorrosion ability than the epoxy coating contains MBT-loaded HNTs after immersion in 3.5 wt% sodium chloride solution for 96 h. Crucially, the pH-responsive anticorrosion material we fabricated can offer a rapid self-healing performance when the coating damaged by mechanical scratch via visual test and atomic absorption spectroscopy.

High thermal conductivity and high impact strength of epoxy nanodielectrics with functionalized halloysite nanotubes

Hailin Mo,Ke Yang,Shengtao Li,Pingkai Jiang

Epoxy nanodielectrics with high thermal conductivity and high impact strength have become the increasingly desirable material of the electronic and electric industries. In this paper, three functionalized halloysite nanotubes (HNTs) named p-HNTs (treated by KH 560), b-HNTs (in situ grafted by benzidine) and d-HNTs (in situ grafted by 4,4′-(1,1′-biphenyl-4,4′-diyidioxy)dianiline) were used to fabricate thermally conductive epoxy/HNTs nanodielectrics with a high impact strength. It was found that the surface modification of HNTs play very important roles in enhancing the mechanical, thermal and dielectric properties of epoxy nanodielectrics. The obtained epoxy/b-HNTs nanodielectrics with 60 wt% filler presented the highest thermal conductivity of 0.85 W m−1 K−1 (about 30% higher than that of epoxy/HNTs nanodielectrics). The impact strength of epoxy/b-HNTs nanodielectrics is about 5.8 kJ m−2, 1.5 times that of epoxy/HNTs nanodielectrics. The epoxy/b-HNTs nanodielectrics also possessed excellent thermal stability and electrical insulation properties. In summary, the epoxy/b-HNTs nanodielectrics showed the best overall performance among all epoxy thermosets/in situ grafting HNTs. The results of the SEM images showed that the improved physical properties of epoxy nanodielectrics were attributed to the increased interaction between in situ grafted HNTs and the epoxy matrix and better dispersion of the in situ grafted HNTs in the epoxy matrix. The results suggested that the obtained epoxy nanodielectrics might be promising as efficient heat-releasing materials for thermal management and next generation electronic devices.

Spray-dried magnetic chitosan/Fe3O4/halloysite nanotubes/ofloxacin microspheres for sustained release of ofloxacin

Qin Wang,Junping Zhang,Aiqin Wang

A series of magnetic chitosan/Fe3O4/halloysite nanotubes/ofloxacin (CTS/Fe3O4/HNTs/OFL) microspheres was prepared by spray-drying for the sustained release of OFL. CTS was in situ crosslinked by glutaraldehyde in the spray-drying process. The magnetic microspheres were characterized by FT-IR, scanning electron microscopy and thermogravimetric analysis. The magnetic properties, encapsulation efficiency, drug loading and in vitro sustained release properties of the magnetic microspheres for OFL were also evaluated. The CTS/Fe3O4/HNTs/OFL microspheres show superparamagnetic properties and fast magnetic response. The Fe3O4 nanoparticles have a remarkable effect on the surface morphology of the microspheres compared with HNTs. The encapsulation efficiency and the cumulative release are closely related to HNTs and Fe3O4 contents, crosslinking density and CTS concentration. OFL is released from the magnetic CTS/Fe3O4/HNTs/OFL microspheres via anomalous transport.

Multifunctional nanocomposite based on halloysite nanotubes for efficient luminescent bioimaging and magnetic resonance imaging

Tao Zhou,Lei Jia,Yi-Feng Luo,Jun Xu,Ru-Hua Chen,Zhi-Jun Ge,Tie-Liang Ma,Hong Chen,Tao-Feng Zhu