Photoinduced DNA Cleavage of Fullerols,Water-Soluble Polyhydroxylated [C_(60)] Fullerene Derivatives

The effects of polyhydroxylated [C60 ] fullerene derivatives fullerols on DNA was studied, using the piasmid pXJ41-neo DNA as the experimental model. The cleaved DNA products were detected by agarose gel electrophoresis. The results showed that fullerols could stimulate DNA cleavage in dose and irradiation dependent manners. 0.4 mmol/L fullerols together with 1.5 h exposure to a 500 W tungsten halogen lamp at a distance of 20 cm could convert most of plasmid DNA from the intact form into the nicked and linear forms. Scavengers of various reactive oxygen species （ROS） including sodium azide, mannitol and superoxide dismu- tase （SOD） could inhibit the photoinduced DNA cleavage of fuUerols. These data presented for the first time the photoinduced biological activities of fullerols, and implied a possible use of these fullerene derivatives as the candidates for novel photosensitizers in the biomedical therapy.

Laser flash photolysis of fullerols of C_(60) and of C_(70) in aqueous solutions

Fullerols of C 60 and of C 70 \ [C 60 (OH)\-\%n\%, C 70 (OH)\-\%m\%], water\|soluble fullerene derivatives, unlike some other fullerene derivatives (such as C 60 (C\-4H\-6O), C 60 (C\-3H\-7N) and C 60 [C(COOEt)\-2]\-\%x\%), do not result in excited triplet state but in ionization via monophotonic process in aqueous solutions with 248 nm laser. The quantum yields of formation of hydrated electron ( Φ e - ) are determined to be 0.08 and 0.11 for fullerols of C 60 and of C 70 respectively at room temperature (ca. 15℃) with KI solution used as reference. By laser flash photolysis and oxidation of sulfate radical anion SO -· \-4, the fullerol radical cation or neutral radical of C 60 is confirmed to be existent and the transient absorption spectra of fullerol radical cation of C 70 are observed for the first time.

SYNTHESIS AND CHARACTERIZATION OF HYDROXYLATED FULLERENE EPOXIDE—AN INTERMEDIATE FOR FORMING FULLEROL

A new C 60 derivative hydroxylated fullerene epoxide [C 60 (OH) x (O) y ] was prepared by the reaction of C 60 benzene solution with aqueous NaOH and H 2O 2 in the presence of tetrabutylammonium hydroxide(TBAH) as the catalyzer. The structure of hydroxylated fullerene epoxide was characterized by FT IR, NMR and MS , and it was found that it is easy to hydrolyze to fullerol.

An Improved Method for Fullerol Preparation Based on Dialysis

A dialysis-based method was developed to remove Na ions in fullerol preparation by a conventional synthetic route. Fullerol was synthesized using a typical two-phase reaction in the presence of tetrabutylammonium hydroxide. Its structure was confirmed by UV spectra, Fourier transform infrared spectroscopy spectra, 1 H nuclear magnetic resonance, and matrix-assisted laser desorption/ionization time of flight mass spectra. The content of Na element was determined by inductive coupled plasma atomic emission spectroscopy. The mass content of Na in the product obtained from the conventional route was about 10%, and it could be almost completely eliminated by dialysis with a membrane of molecular weight cut-off (MWCO) 8-15 kDa. The yield of fullerol by the dialysis method was slightly higher than by the conventional route. These results indicate that dialysis may have a potential application for fullerol preparation.

Fullerol-hydrogel microfluidic spheres for in situ redox regulation of stem cell fate and refractory bone healing

The balance of redox homeostasis is key to stem cell maintenance and differentiation.However,this balance is disrupted by the overproduced reactive oxygen species(ROS)in pathological conditions,which seriously impair the therapeutic efficacy of stem cells.In the present study,highly dispersed fullerol nanocrystals with enhanced bioreactivity were incorporated into hydrogel microspheres using one-step innovative microfluidic technology to construct fullerol-hydrogel microfluidic spheres(FMSs)for in situ regulating the redox homeostasis of stem cells and promoting refractory bone healing.It was demonstrated that FMSs exhibited excellent antioxidant activity to quench both intracellular and extracellular ROS,sparing stem cells from oxidative stress damage.Furthermore,these could effectively promote the osteogenic differentiation of stem cells with the activation of FoxO1 signaling,indicating the intrinsically osteogenic property of FMSs.By injecting the stem cells-laden FMSs into rat calvarial defects,the formation of new bone was remarkably reinforced,which is a positive synergic effect from modulating the ROS microenvironment and enhancing the osteogenesis of stem cells.Collectively,the antioxidative FMSs,as injectable stem cell carriers,hold enormous promise for refractory bone healing,which can also be expanded to deliver a variety of other cells,targeting diseases that require in situ redox regulation.