Extraction and Purification of Nicotine from Tobacco Rhizomes by Supercritical CO2.

Currently, in the ongoing development of the tobacco industry, a large amount of tobacco rhizomes is discarded as waste. These wastes are usually disposed of through incineration or burial. However, these tobacco wastes still have some economic value. High-purity nicotine has a promising market outlook as the primary raw material for electronic cigarette liquid. Nicotine is not only found in tobacco leaves but also in the rhizomes of tobacco plants. This study presents a method for treating tobacco waste and extracting high-purity nicotine from it. After mixing the raw material powder and entrainer in specific ratios, as much of the nicotine in tobacco roots can be extracted as possible using supercritical carbon dioxide extraction. The effects of temperature, the ratio of the entrainer, and the volume fraction of ethanol in the entrainer on the nicotine yield in supercritical fluid extraction (SFE) at 25 MPa for 120 min were discussed. By using 90% ethanol (a raw material mass-to-volume ratio of 1:5) as the entrainer, we obtained the highest nicotine yield of 0.49% at 65 °C. Meanwhile, the purity of the crude extract was 61.71%, and after purification, it increased to 97.57%. In this way, we can not only obtain nicotine with market value but also further reduce the harm to the environment caused by tobacco waste disposal.

Biosynthesis of Ag nanoparticles and two-dimensional element distribution in Arabidopsis.

Metallic nanoparticles can be synthesised in living plants, which provide a friendly approach. In this work, the authors aimed to study the synthesis of silver nanoparticles (AgNPs) in Arabidopsis and the two-dimensional (2D) distribution of Ag and other elements (Ca, P, S, Mg, and CI) in the Arabidopsis plant tissues. The concentrations of Ag in the plant tissues were determined by inductively coupled plasma-atomic emission spectrometer, showing that the majority of Ag was retained in the roots. Transmission electron micrographs showed the morphology of AgNPs and the location in plant cells. The distributions of Cl and Ag were consistent in plant tissues by 2D proton-induced X-ray emission. In conclusion, this is the first report of the AgNP synthesis in Arabidopsis living plants and its 2D distribution of important elements, which provide a new clue for further research.

Investigation on the 2D-Distribution of Metallic Elements after Hair Dyeing.

Long-term use of hair dyes has potential effects on metal content in hair. However, little research dissects the specific distribution and composition variations of the metal after dyeing. In this study, we investigated the morphological change and metallic elements content variation after dyeing. The results showed that the concentration of essential metal elements decreased, among which the Ca, K, and Na decreased sharply even above 50%. As for the heavy metal, the most significant observation is that Pb increased almost by five times after dyeing. Besides, it revealed, using scanning electron microscope coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), that Pb concentrated at the outer layer of the hair. In addition, two-dimensional proton-induced X-ray emission (2D-PIXE) was applied to analyze the distribution of metallic elements along the longitudinal and cross section of the hair. The results showed that Ca and Zn distributed evenly in the hair along the longitudinal and cross section. It is the first time that 2D-PIXE is applied to analyze the metallic distribution in the hair. This method exhibits high sensitivity and can be widely used in the environmental and medical field to analyze the distribution of metallic elements.

In vivo biosynthesis and spatial distribution of Ag nanoparticles in maize (Zea mays L.).

Nanoparticles (NPs), especially biosynthesised in living plants by absorbing soluble salts and reducing metal ions, are extensively used in various fields. This work aimed at investigating the in vivo biosynthesis of silver NPs (Ag-NPs) in maize and the spatial distribution of the NPs and some important nutrient elements in the plant. The content of silver in plant was examined by inductively coupled plasma-atomic emission spectrometer showing that Ag can be absorbed by plant as soluble salts. The NPs in different parts of maize plant were detected and analysed by transmission electron microscopy, demonstrating the synthesis of NPs and their transport from the root to the shoots. Two-dimensional proton induced X-ray emission of silver, chlorine and several nutrient elements elucidated the possible relationship between synthesis of NPs and several nutrient elements in plant tissues. To their knowledge, this is the first report of possibility of synthesis of Ag-NPs in living plants maize (Zea mays L.). This study presents direct evidence for synthesis of NPs and distribution of related nutrient elements in maize, which has great significance for studying synthetic application of NPs in crop plants.

Biosynthesis of silver nanoparticles using Euglena gracilis, Euglena intermedia and their extract.

Extracellular and intracellular biosynthesis of silver nanoparticles (AgNPs) by Euglena gracilis (EG) strain and Euglena intermedia (EI) strain are reported in this study. The obtained nanoparticles showed an absorption peak approximates 420 nm in the UV-visible spectrum, corresponding to the plasmon resonance of AgNPs. According to the result of inductively coupled plasma-atomic emission spectrometer, the intakes of silver ions by EI and EG are roughly equal. The transmission electron microscope (TEM) analysis of the successful in vivo and in vitro synthesised AgNPs indicated the sizes, ranging from 6 to 24 nm and 15 to 60 nm in diameter, respectively, and a spherical-shaped polydispersal of the particles. The successful formation of AgNPs has been confirmed by energy dispersive X-ray analysis connected to the TEM. The Fourier transform infrared spectroscopy measurements reveal the presence of bioactive functional groups such as amines are found to be the capping and stabilising agents of nanoparticles. To our knowledge, this is the first report where two kinds of Euglena microalga were used as the potential source for in vivo and in vitro biosynthesis of AgNPs.

Tumor-Targeting Multifunctional Rattle-Type Theranostic Nanoparticles for MRI/NIRF Bimodal Imaging and Delivery of Hydrophobic Drugs.

The development of theranostic systems capable of diagnosis, therapy, and target specificity is considerably significant for accomplishing personalized medicine. Here, a multifunctional rattle-type nanoparticle (MRTN) as an effective biological bimodal imaging and tumor-targeting delivery system is fabricated, and an enhanced loading ability of hydrophobic anticancer drug (paclitaxel) is also realized. The rattle structure with hydrophobic Fe3 O4 as the inner core and mesoporous silica as the shell is obtained by one-step templates removal process, and the size of interstitial hollow space can be easily adjusted. The Fe3 O4 core with hydrophobic poly(tert-butyl acrylate) (PTBA) chains on the surface is not only used as a magnetic resonance imaging (MRI) agent, but contributes to improving hydrophobic drug loading amount. Transferrin (Tf) and a near-infrared fluorescent dye (Cy 7) are successfully modified on the surface of the nanorattle to increase the ability of near-infrared fluorescence (NIRF) imaging and tumor-targeting specificity. In vivo studies show the selective accumulation of MRTN in tumor tissues by Tf-receptor-mediated endocytosis. More importantly, paclitaxel-loaded MRTN shows sustained release character and higher cytotoxicity than the free paclitaxel. This theranostic nanoparticle as an effective MRI/NIRF bimodal imaging probe and drug delivery system shows great potential in cancer diagnosis and therapy.

Silica composite nanoparticles containing fluorescent solid core and mesoporous shell with different thickness as drug carrier.

Nonporous silica transitional approach was employed to create core-shell architectural nanocomposites, which performed particularly well in morphology and controllable synthesis. The silica nanocomposites containing fluorescent solid SiO2 core and mesoporous silica shell (F-nSiO2/mSiO2) presented distinct structures of narrow size distribution, stable and shell thickness independent fluorescence, and high specific surface area. Furthermore, the thickness of mesoporous shell could be precisely tailored by the amount of TEOS and solid SiO2 seeds. Drug delivery study of F-nSiO2/mSiO2 with different mesoporous thicknesses were carried out, and Peppas equation was adopted to demonstrate the controlled releasing mechanism of doxorubicin (DOX). The diffusion rate of DOX from F-nSiO2/mSiO2 nanocomposites depended on the thickness of mesoporous shell and electrostatic interaction between drug and silanol group, which facilitated an enhanced drug releasing activity at pH 5.5 than 7.4. What's more, particles loaded DOX showed similar cytotoxicity compared with pure DOX, while no obvious cytotoxicity of carrier was observed in MTT tests for blank particles. These characteristics mentioned above implied that core/shell structured F-nSiO2/mSiO2 had a great potential for controlled drug delivery system.

General one-pot strategy to prepare multifunctional nanocomposites with hydrophilic colloidal nanoparticles core/mesoporous silica shell structure.

A general and facile strategy was developed to coat hydrophilic inorganic nanoparticles directly with mesoporous silica nanoparticles (MSNs). The cationic surfactant of cetyltrimethylammonium bromide (CTAB) was adsorbed to various negatively charged CdTe quantum dots, Fe(3)O(4) nanocrystals or Au nanoparticles, introducing the bilayer of CTAB overcoating with positive charge. The subsequent sol-gel reaction of TEOS with the basic catalyst resulted in uniform nanocomposites. The concentration of CTAB and NH(4)OH in the recipe strongly influenced the number of inorganic nanoparticles in the nanocomposites and the homogeneity of MSNs shell. One dimensional Au nanorods and larger size of solid SiO(2) nanoparticles were also able to coat with MSNs using a similar synthetic procedure. The proposed method was greatly simplified without the help of any mediators or silane coupling agents and excellent mesostructural performance was readily achieved. Compared to the methods known from the literatures for the coating of hydrophobic nanoparticles, this efficient way is especially useful for trapping different hydrophilic nanoparticles with arbitrary sizes and shapes into MSNs. These highly versatile multifunctional nanocomposites, together with the pH-responsible drug release behaviors, non-toxicity to normal cells and ease of uptake into cancer cells, are expected to be utilized as drug delivery system for simultaneous imaging and therapeutic applications.

Facile synthesis of pH sensitive polymer-coated mesoporous silica nanoparticles and their application in drug delivery.

pH-responsive polymer shell chitosan/poly (methacrylic acid) (CS-PMAA) was coated on mesoporous silica nanoparticles (MSN) through the facile in situ polymerization method. The resultant composite microspheres showed a flexible control over shell thickness, surface charges and hydrodynamic size by adjusting the feeding amount of MSN and the molar ratio of [-NH(2)]/MAA. The MSN/CS-PMAA composite microspheres were stable in the pH range of 5-8 as well as in the physiological saline (0.15M NaCl). Doxorubicin hydrochloride (DOX) was applied as a model drug to investigate the drug storage and release behavior. The results demonstrated that DOX could be effectively loaded into the composite microspheres. The cumulative release of DOX-loaded composite microspheres was pH dependent and the release rate was much faster at low pH (5.5) than that of pH 7.4. The cytotoxicity test by MTT assay showed that the blank carrier MSN/CS-PMAA microspheres were suitable as drug carriers. The cellular uptake of composite microspheres was investigated by confocal laser scanning microscopy (CLSM), which indicated that MSN/CS-PMAA could deliver the drugs into HeLa cell. The above results imply that the composite microspheres are a promising drug delivery system for cancer therapy.

Facile phase transfer of hydrophobic nanoparticles with poly(ethylene glycol) grafted hyperbranched poly(amido amine).

In order to enhance the dispersion ability of hydrophobic nanoparticles in water while maintaining their unique properties, we utilized poly(ethylene glycol) grafted hyperbranched poly(amido amine) (h-PAMAM-g-PEG) to modify three types of hydrophobic nanoparticle, CdSe, Au, and Fe(3)O(4), and transferred them into water to extend their applications in biology. Considering the large amounts of amino groups in hyperbranched poly(amido amine) (h-PAMAM) polymer, complexation interaction between h-PAMAM-g-PEG copolymer and nanoparticles was achieved and ligand exchange between the copolymers and original small molecules ligands occurred. The transferred nanoparticles could be easily dispersed in water with better stability, and their unique properties, such as fluorescence, surface plasmon resonance, and superparamagnetism, were well maintained in the ligand exchange process. In addition, increasing the number of grafted PEG showed a negative effect on the ligand exchange process. Due to the existence of h-PAMAM-g-PEG ligands, the stabilized nanoparticles have improved stability in aqueous and ionic solutions. In the case of CdSe nanoparticles, the h-PAMAM-g-PEG layer leads to a lower cytotoxicity when compared with bare CdSe particles, and they could be directly used in bioimaging.

Stable aqueous ZnO@polymer core-shell nanoparticles with tunable photoluminescence and their application in cell imaging.

Stable aqueous solutions of ZnO@polymer core-shell nanoparticles with tunable photoluminescence are prepared through a simple sol-gel route. The copolymer shell has many hydrophilic external groups and a hydrophobic internal layer which connects ZnO cores through covalent bonds. The optimal samples show quantum yield above 50% and stable emission for months. These samples with their concentrations of below 0.2 mg/mL are nontoxic to human cells. After uptake of these ZnO@polymer nanoparticles, the luminescent cells have enough life under UV light for microscopic imaging.

Photodynamic effects of 5-aminolevulinic acid and its hexylester on several cell lines.

5-aminolevulinic acid (ALA) and its hexyl-ester (He-ALA) has shown promising results in photodynamic detection and therapy of tumors. In this work, the photodynamic effects of ALA and He-ALA on neuroblastoma cells, hepatoma cells and fibroblast cells were comparatively studied. With the detection of fluorescence emission spectra, protoporphyrin IX (PpIX) induced by ALA or He-ALA was observed in these three cell lines. Confocal laser scanning microscope showed the diffuse PpIX fluorescence in cytoplasm of neuroblastoma cells. The kinetics of PpIX accumulation were different in these three kinds of cells. The PpIX content in hepatoma cells and fibroblast cells continuously increased with the incubation time of drugs until 12 h, while in neuroblastoma cells the PpIX content saturated around 8 h after incubation with ALA or He-ALA. In addition, the PpIX concentration in neuroblastoma cells was obviously higher than that in hepatoma cells and fibroblast cells, indicating that the PpIX production is cell line dependent. When incubated with ALA and irradiated with light, near 90% neuroblastoma cells were destroyed, while for hepatoma cells and fibroblast cells the death rate was around 50%. The results demonstrate that neuroblastoma cells are more sensitive to ALA-PDT and the neuro-tumor cells may be well suited for the treatment of ALA mediated photosensitization. Comparing to ALA, He-ALA can reach the similar results concerned PpIX production and PDT damaging in all three kinds of cells but with 10 times lower incubation concentration, demonstrating that He-ALA has higher efficiency than ALA on inactivation of cancer cells in vitro.

Comparison of 5-aminolevulinic acid and its hexylester mediated photodynamic action on human hepatoma cells.

5-Aminolevulinic acid (ALA) is a precursor to heme synthesis pathway and currently used to induce endogenous protoporphyrin IX (PpIX, a potent photosensitizer) for photodynamic therapy of cancer. ALA has, however, a limited ability to cross cellular membranes due to its low lipid solubility. The use of lipophilic ALA esters may increase cellular uptake, which results in an enhanced PpIX synthesis. In the present study, a comparison of ALA and its hexyl ester (He-ALA) was made in the QGY human hepatoma cell line with respect to PpIX production and its photocytotoxicity. The fluorescence emission spectrum of the cells incubated with He-ALA was identical to that of PpIX, indicating that He-ALA could induce PpIX in the cells. Fluorescence images demonstrated that the He-ALA induced PpIX was localized in the cytoplasm of the cells. Moreover, a similar amount of Pp IX was found in the cells incubated with 0.2 mmol/L He-ALA or 2 mmol/L ALA and a similar level of cell survival was reached following light exposure. These results suggest that He-ALA is much more efficient at producing PpIX and photocytotoxicity than ALA itself in the cells.