共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
In this article we report experimental and theoretical results of angle-dependent laser light scattering of nano titanium
dioxide nucleated on silica particles. It was observed that the experimental scattering profile from nano-titania coated silica
(TCS) particle resembles that of a Rayleigh scattering. It can be inferred from the light scattering profile that nucleating
fine particles onto a surface of a bigger particle (core), the resulting scattering profile is dominated by the smaller particles.
Thin film transmittance measurement of TCS particles also supports this claim. The theoretical scattering predictions do not
match with the experimental findings and the reasons for the discrepancies are addressed. This Rayleigh-like scattering property
of TCS particles can be used in cosmetic formulations as a replacement for nanoparticles to provide protection from harmful
ultraviolet rays. This study helps to provide insights into these systems for their potential usage in cosmetics. 相似文献
3.
Biogenic silica nanoparticles (25-30 nm in diameter) were synthesized from rice husks. The characterizations revealed that the silica nanoparticles were composed of smaller primary particles (ca. 4.2 nm in diameter), and their clustering led to a porous structure with a surface area of 164 m(2)/g. Under the controlled melting catalyzed by K(+), such silica nanoparticle clusters can gradually fuse to form semicrystalline porous silica frameworks with tunable pore size and structural integrity. 相似文献
4.
5.
The suitability of using spherical metal and dielectric nanoparticles on the top of a silicon solar cell has been investigated. An enhancement index factor (EIF) for each wavelength of light and an averaged EIF for the AM 1.5 solar spectrum, weighted by the photon flux, has been introduced. These factors estimate the effect of the nanoparticles in improving the performance of the solar cells, considering the absorption loss due to joule heating, fraction of radiation scattered into the substrate and the front scattered radiation pattern. A systematic comparison between silver and dielectric nanoparticles (silica, silicon nitride, titanium dioxide) shows that titanium dioxide and silicon nitride nano particles of sizes ≥100?nm exhibit larger enhancements compared to that of silver nanoparticles of similar sizes. Further, as the dielectric constant of the dielectric nanoparticles increases, the optimal particle size corresponding to maximal enhancement shifts towards lower value. At optimal particle sizes, the enhancement is 1.5–2 times greater than that due to silver nanoparticles. 相似文献
6.
The in vivo biodistribution and urinary excretion of spherical mesoporous silica nanoparticles (MSNs) are evaluated by tail-vein injection in ICR mice, and the effects of the particle size and PEGylation are investigated. The results indicate that both MSNs and PEGylated MSNs of different particle sizes (80-360 nm) distribute mainly in the liver and spleen, a minority of them in the lungs, and a few in the kidney and heart. The PEGylated MSNs of smaller particle size escape more easily from capture by liver, spleen, and lung tissues, possess longer blood-circulation lifetime, and are more slowly biodegraded and correspondingly have a lower excreted amount of degradation products in the urine. Neither MSNs nor PEGylated MSNs cause tissue toxicity after 1 month in vivo. 相似文献
7.
Xiaoqiong Cao Yanhui Han Min Gu Hengjun Du Mingyue Song Xiaoai Zhu Gaoxing Ma Che Pan Weicang Wang Ermin Zhao Timothy Goulette Biao Yuan Guodong Zhang Hang Xiao 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(36)
The recent ban of titanium dioxide (TiO2) as a food additive (E171) in France intensified the controversy on safety of foodborne‐TiO2 nanoparticles (NPs). This study determines the biological effects of TiO2 NPs and TiO2 (E171) in obese and non‐obese mice. Oral consumption (0.1 wt% in diet for 8 weeks) of TiO2 (E171, 112 nm) and TiO2 NPs (33 nm) does not cause severe toxicity in mice, but significantly alters composition of gut microbiota, for example, increased abundance of Firmicutes phylum and decreased abundance of Bacteroidetes phylum and Bifidobacterium and Lactobacillus genera, which are accompanied by decreased cecal levels of short‐chain fatty acids. Both TiO2 (E171) and TiO2 NPs increase abundance of pro‐inflammatory immune cells and cytokines in the colonic mucosa, indicating an inflammatory state. Importantly, TiO2 NPs cause stronger colonic inflammation than TiO2 (E171), and obese mice are more susceptible to the effects. A microbiota transplant study demonstrates that altered fecal microbiota by TiO2 NPs directly mediate inflammatory responses in the mouse colon. Furthermore, proteomic analysis shows that TiO2 NPs cause more alterations in multiple pathways in the liver and colon of obese mice than non‐obese mice. This study provides important information on the health effects of foodborne inorganic nanoparticles. 相似文献
8.
微乳液化学剪裁制备纳米钛酸钡和二氧化钛 总被引:1,自引:0,他引:1
以钛酸丁酯、氢氧化钡和正己醇制备凝胶,用吐温-80/正已醇/环己烷/水制成w/O型微乳液在25℃下进行化学剪裁,将前驱物在550℃下煅烧,分别制备出了纳米钛酸钡和纳米二氧化钛.对产物进行X-射线粉末衍射(XRD)、透射电镜(TEM)、红外(IR)和差热(DTA)分析,研究了煅烧温度对BaTi03和Ti02纳米质点粒径和组成的影响.结果表明,最好的煅烧温度是550℃.所得纳米钛酸钡为具有较好晶型的六方晶体,粒径在30~42nm之间,钡钛摩尔比为1:1;纳米二氧化钛为单一的锐钛矿型八面体结构,平均粒径小于50nm.实验表明,通过凝胶.微乳液法合成的纳米物质可以有效地减少团聚,控制微粒的组成和粒径,且操作简单,成本低. 相似文献
9.
G. Devanand Venkatasubbu S. Ramasamy V. Ramakrishnan J. Kumar 《Advanced Powder Technology》2013,24(6):947-954
A novel titanium dioxide nanocarrier was synthesized for targeted delivery of the anticancer drug, paclitaxel, by grafting folic acid (FA) onto the PEGylated titanium dioxide nanoparticles. Titanium dioxide is used in biomedical field for its stability and no toxicity characteristics. Titanium dioxide is one of the most promising nanoparticles (NPs) capable of a wide variety of applications in medicine and life science. Polyethylene glycol (PEG), when attached to the surface of the nanoparticles, increases the biocompatibility of the nanoparticles. PEGylated nanocarriers evade the reticuloendothelial system (RES). Folic acid (FA) is used as the ligand to target folate receptors, which are found abundant in cancer cells. FA–PEG–TiO2 nanoparticles when used as drug carriers have the ability to target cancer cells and also capable of evading the reticuloendothelial system. Titanium dioxide nanoparticles were synthesized by wet chemical method. It was annealed at 450° for 3 h. XRD analysis confirms the formation of anatase titanium dioxide. Analyses by transmission electron microscopy (TEM) and dynamic light scattering (DLS) revealed that the nanoparticles had an average size of 12 nm and uniform size distribution. The PEGylation and folic acid grafting was confirmed by UV spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). The study on the loading of anticancer drug paclitaxel revealed that the titanium dioxide nanocarrier possessed a considerably higher adsorption capability. In addition, the in vitro release profile of paclitaxel from FA–PEG–TiO2 nanoparticles was characterized by an initial fast release followed by a sustained release phase. 相似文献
10.
The majority of cancer mortality is associated with cancer metastasis. Epithelial‐to‐mesenchymal transition (EMT) is a process by which cells attain migratory and invasive properties, eventually leading to cancer metastasis. Here, it is shown that titanium dioxide nanoparticles (nano‐TiO2), a common food additive, can induce the EMT process in colorectal cancer cells. Nano‐TiO2 exposure is observed to activate transforming growth factor‐β (TGF‐β)/mitogen‐activated protein kinase (MAPK) and wingless (Wnt) pathways, and drive the EMT process. Similarly, silica nanoparticles (nano‐SiO2) and hydroxyapatite nanoparticles (nano‐HA), as food‐based additives, can be ingested and accumulated in the stomach, and are found to be able to induce the EMT progression. The implication of this work can be profound for colorectal cancer patients where these food additives may unknowingly and unnecessarily hasten the progression of their cancers. 相似文献
11.
Nanomaterials, recently have found burgeoning attention in the field of agriculture, owing to the positive correlation between nanoparticle (NP) application and the enhanced nutritional status of the applied plants. A wide range of NPs, namely carbon‐based NPs, titanium dioxide NPs, silica NPs etc. has been found to influence plants in a positive way by increasing their nutrient uptake ratio, nutrient usage efficiency, among others. All these attributes have paved the way for possible improvement in plant growth, development, vigour etc. through the use of these NPs, mainly as nanofertiliser. In view of all these, it can also be concluded that in the global scenario of increased demand of food production and supply in the coming years, nanotechnology promises to play a critical role. In this review, an attempt has been made to consolidate all the positive trends with respect to application of NPs on plants, along with their probable mechanism of action, which may provide a comprehensive insight for researchers working in this field.Inspec keywords: reviews, nanoparticles, agriculture, nanotechnology, titanium compounds, crops, nanofabrication, fertilisers, food products, nanobiotechnologyOther keywords: nanotechnological interventions, plant growth, positive correlation, nanoparticle application, enhanced nutritional status, applied plants, carbon‐based NPs, titanium dioxide NPs, silica NPs, influence plants, nutrient uptake ratio, nutrient usage efficiency, positive trends 相似文献
12.
Ariano P Zamburlin P Gilardino A Mortera R Onida B Tomatis M Ghiazza M Fubini B Lovisolo D 《Small (Weinheim an der Bergstrasse, Germany)》2011,7(6):766-774
The effects of St?ber silica nanoparticles on neuronal survival, proliferation, and on the underlying perturbations in calcium homeostasis are investigated on the well-differentiated neuronal cell line GT1-7. The responses to nanoparticles 50 and 200 nm in diameter are compared. The 50-nm silica affects neuronal survival/proliferation in a dose-dependent way, by stimulating apoptotic processes. In contrast, the 200-nm silica does not show any toxic effect even at relatively high concentrations (292 μg mL?1). To identify the mechanisms underlying these effects, the changes in intracellular calcium concentration elicited by acute and chronic administration of the two silica nanoparticles are analyzed. The 50-nm silica at toxic concentrations generates huge and long-lasting increases in intracellular calcium, whereas the 200-nm silica only induces transient signals of much lower amplitude. These findings provide the first evidence that silica nanoparticles can induce toxic effects on neuronal cells in a size-dependent way, and that these effects are related to the degree of perturbation of calcium homeostasis. 相似文献
13.
Jonas Klein Michael Philippi Fatih Alarslan Tim Jähnichen Dirk Enke Martin Steinhart Markus Haase 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(10):2207674
High-temperature treatment of functional nanomaterials, through postsynthesis calcination, often represents an important step to unlock their full potential. However, such calcination steps usually severely limit the preparation of colloidal solutions of the nanoparticles due to the formation of sintered agglomerates. Herein, a simple route is reported to obtain colloidal solutions of calcined n-conductive antimony doped tin oxide (ATO) as well as titanium dioxide (TiO2) nanoparticles without the need for additional sacrificial materials. This is achieved by making use of the reduced contact between individual nanoparticles when they are assembled into aerogels. Following the calcination of the aerogels at 500 °C, redispersion of the nanoparticles into stable colloidal solutions with various solvents can be achieved. Although a slight degree of sintering is inevitable, the size of the resulting aggregates in solution is still remarkably small with values below 30 nm. 相似文献
14.
Kin Yuen Leong Z. A. Najwa K. Z. Ku Ahmad Hwai Chyuan Ong 《International Journal of Thermophysics》2017,38(5):77
Water is regarded as a poor absorber of solar energy. This affects the efficiency of solar thermal systems. The addition of nanoparticles to heat transfer fluids used in solar thermal systems can enhance their optical properties. These new-generation heat transfer fluids are known as nanofluids. The present study investigates the stability and optical properties of three nanofluids, including aluminum oxide (13 nm and <50 nm) and titanium dioxide (21 nm) nanofluids. The stability of the nanofluids was observed through a photo-capturing method and zeta potential measurements. Ultraviolet–visible (UV–Vis) spectrophotometer was used to measure the absorbance and transmittance of the prepared nanofluids. The effect of factors such as type of particle, type of surfactant, and pH of the solution on the optical properties of the nanofluids was also investigated. We found that the titanium dioxide nanofluid had better optical properties but lower stability compared to aluminum oxide nanofluids. 相似文献
15.
Simulated Sunlight‐Mediated Photodynamic Therapy for Melanoma Skin Cancer by Titanium‐Dioxide‐Nanoparticle–Gold‐Nanocluster–Graphene Heterogeneous Nanocomposites
下载免费PDF全文
![点击此处可从《Small (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Yan Cheng Yun Chang Yanlin Feng Ning Liu Xiujuan Sun Yuqing Feng Xi Li Haiyuan Zhang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(20)
Simulated sunlight has promise as a light source able to alleviate the severe pain associated with patients during photodynamic therapy (PDT); however, low sunlight utilization efficiency of traditional photosensitizers dramatically limits its application. Titanium‐dioxide‐nanoparticle–gold‐nanocluster–graphene (TAG) heterogeneous nanocomposites are designed to efficiently utilize simulated sunlight for melanoma skin cancer PDT. The narrow band gap in gold nanoclusters (Au NCs), and staggered energy bands between Au NCs, titanium dioxide nanoparticles (TiO2 NPs), and graphene can result in efficient utilization of simulated sunlight and separation of electron–hole pairs, facilitating the production of abundant hydroxyl and superoxide radicals. Under irradiation of simulated sunlight, TAG nanocomposites can trigger a series of toxicological responses in mouse B16F1 melanoma cells, such as intracellular reactive oxygen species production, glutathione depletion, heme oxygenase‐1 expression, and mitochondrial dysfunctions, resulting in severe cell death. Furthermore, intravenous or intratumoral administration of biocompatible TAG nanocomposites in B16F1‐tumor‐xenograft‐bearing mice can significantly inhibit tumor growth and cause severe pathological tumor tissue changes. All of these results demonstrate prominent simulated sunlight‐mediated PDT effects. 相似文献
16.
Maoquan Chu Qiang Wu Hui Yang Ruiqi Yuan Shengke Hou Yifeng Yang Yajuan Zou Shi Xu Kaiyi Xu Ailing Ji Lingyi Sheng 《Small (Weinheim an der Bergstrasse, Germany)》2010,6(5):670-678
Fluorescent quantum dots (QDs) have great potential for in vivo biomedical imaging and diagnostic applications. However, these nanoparticles are composed of heavy metals and are very small in diameter, and their possible toxicity must therefore be considered. As yet, no studies have reported the transfer of QDs between mother and fetus. The transfer of CdTe/CdS QDs of different sizes and dosages, and with different outer capping materials, from pregnant mice to fetuses is investigated. It is shown that QDs may be transferred from female mice to their fetuses across the placental barrier. Smaller QDs are more easily transferred than larger QDs and the number of QDs transferred increases with increasing dosage. Capping with an inorganic silica shell or organic polyethylene glycol reduces QD transfer but does not eliminate it. These results suggest that the clinical utility of QDs could be limited in pregnant women. 相似文献
17.
Moghal J Kobler J Sauer J Best J Gardener M Watt AA Wakefield G 《ACS applied materials & interfaces》2012,4(2):854-859
Mesoporous silica nanoparticles are used to fabricate antireflectance coatings on glass substrates. The combination of mesoporous silica nanoparticles in conjunction with a suitable binder material allows mechanically robust single layer coatings with a reflectance <0.1% to be produced by simple wet processing techniques. Further advantages of these films is that their structure results in broadband antireflective properties with a reflection minimum that can tuned between 400 nm and 1900 nm. The ratio of binder material to mesoporous nanoparticles allows control of the refractive index. In this report, we discuss how control of the structural properties of the coatings allows optimization of the optical properties. 相似文献
18.
A thin layer of nanoparticle titanium dioxide was immobilized on polyamide 6 (PA6) fiber using titanium sulfate and urea at low temperature hydrothermal condition. The titanium dioxide loaded fabric was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry and thermal gravimetry techniques. The optical and mechanical properties, water absorption and degradation of methylene blue dye under ultraviolet (UV) irradiation of the PA6 fabric before and after treatments were also examined. It was found that when PA6 fabric was treated in titanium sulfate and urea aqueous solution, anatase nanocrystalline titanium dioxide was synthesized and simultaneously adhered onto the fiber surface. The average crystal size of titanium dioxide nanoparticles was about 13.2 nm. The thermal behavior of PA6 fiber distinctly changed and the onset decomposition temperature decreased. As compared with the untreated fabric, the protection against UV radiation was improved. The water absorbency increased slightly. As the fabric dimensions were reduced in warp and weft directions, the breaking load and tensile strain increased to some extent. The titanium dioxide coated fabric could degradate methylene blue dye under UV irradiation. 相似文献
19.
M. A. Pugachevskii 《Technical Physics Letters》2012,38(4):328-331
A method for obtaining titanium dioxide (TiO2) nanoparticles by laser ablation has been developed. Pulsed laser irradiation at an intensity of 109 W/m2 leads to sputtering of titanium dioxide in the form of particles with dimensions within 10?C50 nm. The phase composition and morphology of obtained nanoparticles have been studied by the methods of transmission electron microscopy and X-ray diffraction. Thermal annealing above 600°C leads to an increase in the average particle size and induces the structural transition of titanium dioxide from anatase to rutile modification. Quantitative dependences of the particle size and phase composition on the annealing temperature are established. It is established that, using the laser ablation method, it is possible to obtain the anatase phase of TiO2 with increased thermal stability. 相似文献