Self assembly of amphiphilic C60 fullerene derivatives into nanoscale supramolecular structures

<p>Abstract</p> <p>Background</p> <p>The amphiphilic fullerene monomer (AF-1) consists of a "buckyball" cage to which a Newkome-like dendrimer unit and five lipophilic C₁₂chains positioned octahedrally to the dendrimer unit are attached. In this study, we report a novel fullerene-based liposome termed 'buckysome' that is water soluble and forms stable spherical nanometer sized vesicles. Cryogenic electron microscopy (Cryo-EM), transmission electron microscopy (TEM), and dynamic light scattering (DLS) studies were used to characterize the different supra-molecular structures readily formed from the fullerene monomers under varying pH, aqueous solvents, and preparative conditions.</p> <p>Results</p> <p>Electron microscopy results indicate the formation of bilayer membranes with a width of ~6.5 nm, consistent with previously reported molecular dynamics simulations. Cryo-EM indicates the formation of large (400 nm diameter) multilamellar, liposome-like vesicles and unilamellar vesicles in the size range of 50–150 nm diameter. In addition, complex networks of cylindrical, tube-like aggregates with varying lengths and packing densities were observed. Under controlled experimental conditions, high concentrations of spherical vesicles could be formed. <it>In vitro </it>results suggest that these supra-molecular structures impose little to no toxicity. Cytotoxicity of 10–200 μM buckysomes were assessed in various cell lines. Ongoing studies are aimed at understanding cellular internalization of these nanoparticle aggregates.</p> <p>Conclusion</p> <p>In this current study, we have designed a core platform based on a novel amphiphilic fullerene nanostructure, which readily assembles into supra-molecular structures. This delivery vector might provide promising features such as ease of preparation, long-term stability and controlled release.</p

Self assembly of amphiphilic Cfullerene derivatives into nanoscale supramolecular structures-4

<p><b>Copyright information:</b></p><p>Taken from "Self assembly of amphiphilic Cfullerene derivatives into nanoscale supramolecular structures"</p><p>http://www.jnanobiotechnology.com/content/5/1/6</p><p>Journal of Nanobiotechnology 2007;5():6-6.</p><p>Published online 2 Aug 2007</p><p>PMCID:PMC2000908.</p><p></p>on. Kidney, Liver, and Macrophage cells exhibited little differences when compared to PBS controls after exposure to AF-1 at different concentrations and analyzed for membrane integrity (LDH) as well as cellular proliferation (MTT). Samples A, B, C, D and E are 2 mg/mL AF-1, 0.2 mg/mL AF-1, 0.02 mg/mL AF-1, cells only, and control respectively. Cells were treated with 0.1% HOfor negative control of MTT and 0.9% Triton X-100 for positive control of LDH

Self assembly of amphiphilic Cfullerene derivatives into nanoscale supramolecular structures-2

<p><b>Copyright information:</b></p><p>Taken from "Self assembly of amphiphilic Cfullerene derivatives into nanoscale supramolecular structures"</p><p>http://www.jnanobiotechnology.com/content/5/1/6</p><p>Journal of Nanobiotechnology 2007;5():6-6.</p><p>Published online 2 Aug 2007</p><p>PMCID:PMC2000908.</p><p></p>ckysomes. The scale bar is 100 nm in all the images. In micrographs (A, B, C) AF-1 was prepared in 10 mM HEPES at pH 8.0; in (D, E, F) AF-1 was prepared in 0.2 M phosphate-citrate and in (G, H, I) in 1 × PBS buffer at pH 7.15. The concentration of AF-1 was 2 mg/mL and preparations were made at room temperature. Images are representative of 20–30 different areas on the grid

Self assembly of amphiphilic Cfullerene derivatives into nanoscale supramolecular structures-5

<p><b>Copyright information:</b></p><p>Taken from "Self assembly of amphiphilic Cfullerene derivatives into nanoscale supramolecular structures"</p><p>http://www.jnanobiotechnology.com/content/5/1/6</p><p>Journal of Nanobiotechnology 2007;5():6-6.</p><p>Published online 2 Aug 2007</p><p>PMCID:PMC2000908.</p><p></p>on following several washes with PBS. Cells were fixed and counterstained with DAPI. (A) Superimposed image of fluorescein and DAPI emission. (B) Panel A superimposed with bright field image of cells. (C) Fluorescein emission at 520 nm. (D) DAPI emission at 461 nm. The scale bar for all panels is 50 μm

Self assembly of amphiphilic Cfullerene derivatives into nanoscale supramolecular structures-0

<p><b>Copyright information:</b></p><p>Taken from "Self assembly of amphiphilic Cfullerene derivatives into nanoscale supramolecular structures"</p><p>http://www.jnanobiotechnology.com/content/5/1/6</p><p>Journal of Nanobiotechnology 2007;5():6-6.</p><p>Published online 2 Aug 2007</p><p>PMCID:PMC2000908.</p><p></p>epared in 10 mM citrate at pH 7.0 and in (C) Buckysomes were prepared in 1 × PBS buffer at pH 7.15. The concentration of AF-1 was 2 mg/mL and preparations were made at room temperature. Images are representative of 20–30 different areas on the grid

Self assembly of amphiphilic Cfullerene derivatives into nanoscale supramolecular structures-1

<p><b>Copyright information:</b></p><p>Taken from "Self assembly of amphiphilic Cfullerene derivatives into nanoscale supramolecular structures"</p><p>http://www.jnanobiotechnology.com/content/5/1/6</p><p>Journal of Nanobiotechnology 2007;5():6-6.</p><p>Published online 2 Aug 2007</p><p>PMCID:PMC2000908.</p><p></p>D, E are 200 nm. Image C is a 45° tilt of B. The bilayer diameter is ~6.5 nm. Buckysomes were prepared in 10 mM citrate at pH 7.0 at a concentration of 2.0 mg/mL. (see Methods for detailed methodology on sample preparation)

Self assembly of amphiphilic Cfullerene derivatives into nanoscale supramolecular structures-6

<p><b>Copyright information:</b></p><p>Taken from "Self assembly of amphiphilic Cfullerene derivatives into nanoscale supramolecular structures"</p><p>http://www.jnanobiotechnology.com/content/5/1/6</p><p>Journal of Nanobiotechnology 2007;5():6-6.</p><p>Published online 2 Aug 2007</p><p>PMCID:PMC2000908.</p><p></p>epared in 10 mM citrate at pH 7.0 and in (C) Buckysomes were prepared in 1 × PBS buffer at pH 7.15. The concentration of AF-1 was 2 mg/mL and preparations were made at room temperature. Images are representative of 20–30 different areas on the grid