Enhancement of Water Solubility of Fullerene by Cogrinding with Mixture of Cycloamyloses, Novel Cyclic .ALPHA.-1,4-Glucans, via Solid-Solid Mechanochemical Reaction

Abstract

Improvement of solubility for fullerene (C 60 ) was studied by cogrinding with cycloamyloses using a ball mill in the solid state. Cycloamylose is a novel cyclic a a-1,4-glucan produced from synthetic amylose by enzymatic reaction. Although sample solutions showed a pale yellow for the initial period of cogrinding with cycloamyloses and C 60 , the color varied to brown after 48 h. Subsequently, the solubility of C 60 was improved markedly to 560 (m mg/ml) at 96 h. From powder X-ray diffraction analysis, the peak intensity of crystalline C 60 decreased as the cogrinding time was extended. The UV-VIS absorption spectrum of C 60 shows absorption bands at 262 and 340 nm in water with cycloamyloses, and 258 and 328 nm in n-hexane. These results suggested that C 60 molecules were dispersed into cycloamyloses micellar system and the red-shift of the UV-VIS spectra was due to an intermolecular interaction between C 60 and cycloamyloses.

Large-ring Cyclodextrins

“…In particular, the LR-CD mixture showed a high solubilization effect for cholesterol in comparison with α-, β-and γ-CD. Furthermore, the Tomono group also reported the improvement of the solubility of fullerene (C 60 ) by co-grinding with LR-CD mixture in the solid state (64). The molecular state of C 60 in the complex was evaluated using powder X-ray diffraction, UV-VIS spectroscopy and dynamic light scattering measurement.…”

p-Sulfonatocalix[4]arene and imidazolium zwitterion stabilised nano-arrays of fullerene C60 and C70

“…11 Deep cavity calixarenes which have a larger hydrophobic surface area are effective in water solubilising large hydrophobic molecules, for example b-carotene in the presence of p-4-sulfonatophenyl or benzyl calix[n]arenes. 12 Herein we show that under certain conditions p-sulfonatocalix [4]arene is effective in solubilising fullerenes C 60 and C 70 in water. This is despite the well known lack of complementarity of size and shape of the cavity of this calixarene relative to the fullerenes.…”

“…Fukami et al have developed a C 60 solubilisation method involving mechanochemically co-grinding the fullerene with cycloamyloses, in doing so avoiding the use of organic solvents. 4 Deguchi et al found that C 60 particles as small as 20 nm are readily produced by grinding the fullerene in an agate mortar, the nanoparticles being successfully dispersed in water with or without the aid of a surfactant such as sodium dodecylsulfate. 5 Dispersed nanoparticles of fullerenes in water devoid of a stabilizer have also been developed by Scrivens et al This involves dissolving C 60 in an increasing content of polar molecules, starting with benzene, THF, acetone and then finally water.…”

“…This is despite the well known lack of complementarity of size and shape of the cavity of this calixarene relative to the fullerenes. It is the higher analogue of calixarenes and calix [4]naphthalene that can form such host-guest complexes, 11 with calix [4]arenes usually restricted to binding small molecules such as solvent and gas molecules. 13 We also show that sulfonated functionalised imidazolium zwitterions, with and without the presence of p-sulfonatocalix [4]arene, are effective in preparing water soluble colloidal suspensions of the fullerenes.…”

Cyclodextrins and Polymer Nanoparticles

“…The interesting role of CDs in drug delivery systems is not limited to their role in nanoparticle formation and characteristics-they can also be used in supramolecular structures; for example, two CDs most often b-CD, or their derivatives can form complexes with fullerenes C 60 [117][118][119][120][121], making them water-soluble products and thus easier to use for biological applications, among which are anti-HIV or DNA cleavage activities [122][123][124].…”