http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Proteins and Carbon Nanotubes: Close Encounter in Water
Nepal, Dhriti,Geckeler, Kurt ,E. WILEY-VCH Verlag 2007 Small Vol.3 No.7
<P>The interactions between biological substances and carbon nanotubes (CNTs) and their effect on the nanotubes are of significant importance in this emerging era of nanobiotechnology. Consequently, highly stable dispersions of debundled CNTs in aqueous solution are an important prerequisite for their applications and for the development of nanotube-based molecular electronic and nanobiomedical devices. Here, we report that proteins can work as tools to this end if their primary structure and the pH value of the system are chosen appropriately. Proteins containing a large number of basic residues, for example, histone, are found to be the most promising protein tools for the dispersion of nanotubes. Apart from other interactions, the polarity of the protein seems to play a vital role in obtaining high yields of debundled nanotubes. In addition, an enrichment of metallic nanotubes in the products is observed, which offers a facile approach for separating nanotubes according to their electronic properties in the bulk.</P> <B>Graphic Abstract</B> <P>Watered down: The use of proteins as a tool for the dispersion of single-walled carbon nanotubes (SWNTs) in water is demonstrated. The suitability of the protein depends on its primary structure and the pH of the system. Proteins containing a high number of basic residues, such as histone, are the most promising for the dispersion of SWNTs (see picture). An enrichment of metallic nanotubes in the products is also observed. <img src='wiley_img/16136810-2007-3-7-SMLL200600511-content.gif' alt='wiley_img/16136810-2007-3-7-SMLL200600511-content'> </P>
Nanosized CuO Particles via a Supramolecular Strategy
Premkumar, T.,Geckeler, K. ,E. WILEY-VCH Verlag 2006 Small Vol.2 No.5
<B>Graphic Abstract</B> <P>Uniform cupric oxide nanoparticles have been prepared for the first time via a novel supramolecular complex (see image, left) by thermal decomposition, in which cucurbit[7]uril was selected to encapsulate copper acetate, which acts as the precursor for the CuO nanoparticles (right). The procedure affords particles with a narrow size distribution and of very small diameter (≈5 nm). <img src='wiley_img/16136810-2006-2-5-SMLL200500454-content.gif' alt='wiley_img/16136810-2006-2-5-SMLL200500454-content'> </P>
Cytotoxicity and cellular uptake of lysozyme‐stabilized gold nanoparticles
Lee, Yeonju,Geckeler, Kurt E. Wiley Subscription Services, Inc., A Wiley Company 2012 Journal of biomedical materials research. Part A Vol.a100 No.4
<P><B>Abstract</B></P><P>The particle size and surface properties of gold nanoparticles are critical factors for the interactions between nanoparticles and cells. To produce noncytotoxic gold nanoparticles, a straightforward method for the synthesis of gold nanoparticles designed involving the reduction and stabilization by a protein such as a lysozyme in conjunction with microwave irradiation. The cooperative combination of a lysozyme with a high affinity for metal ions and the microwave irradiation allowed to form biocompatible gold nanoparticles in an aqueous system. In addition, the cell toxicity and the cellular uptake pathways of the gold nanoparticles synthesized against mouse embryonic fibroblast NIH‐3T3 cells were studied and found to be taken up by receptor‐mediated endocytosis. In addition, the lysozyme‐stabilized gold nanoparticles are accumulated in the cytoplasm as well as the nucleus without any significant cytotoxicity. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2012.</P>
pH-Sensitive Dispersion and Debundling of Single-Walled Carbon Nanotubes: Lysozyme as a Tool
Nepal, Dhriti,Geckeler, Kurt ,E. WILEY-VCH Verlag 2006 Small Vol.2 No.3
<P>Highly dispersed and debundled carbon nanotubes were prepared in an aqueous solution of lysozyme using a combination of ultrasonication and ultracentrifugation. The product is a pH-sensitive dispersion, which remains in a highly dispersed state at pH<8 and pH>11, but in an aggregated state at pH 8–11. Photoluminescence measurements show that by changing the pH value, a reversible conversion of the highly dispersed state to the aggregated state (or vice versa) could be observed. Circular dichromism analysis confirmed that the secondary structure, as well as the majority of the tertiary structure, remains intact. Some lysozyme molecules were irreversibly bound to the nanotubes, which is possibly due to π–π or hydrophobic interactions. However, these interactions alone are not enough to produce fine dispersions of the nanotubes. Protonated amine interactions on the defect sites of the nanotubes play a vital role in the stabilization of the nanotubes below the isoelectric point and amine adsorption on the sidewalls of nanotubes occurs in cases where the pH value is higher than the isoelectric point.</P> <B>Graphic Abstract</B> <P>Lysozyme-stabilized carbon nanotubes are highly disperse in aqueous solution, and exhibit pH-sensitive emission. At pH 12.5, a typical emission pattern for individual, isolated nanotubes is obtained, which is not observed at pH 9.0 (see Figure). However, readjusting the pH value back at 12.5 recovered the emission properties. Such pH-sensitive reversibility in the dispersions holds great promise in the development of optical pH sensors. <img src='wiley_img/16136810-2006-2-3-SMLL200500351-content.gif' alt='wiley_img/16136810-2006-2-3-SMLL200500351-content'> </P>