Junpeng Zheng

Planar Quinary Cluster inside a Fullerene Cage: Synthesis and Structural Characterizations of Sc3NC@C80-Ih

The endohedral fullerene Sc(3)NC@C(80)-I(h) has been synthesized and characterized; it has an unprecedented planar quinary cluster in a fullerene cage. It is also the first chemical compound in which the presence of an unprecedented (NC)(3-) trianion has been disclosed. The fascinating intramolecular dynamics in Sc(3)NC@C(80)-I(h) enables the whole molecule to display high polarity and promising ferroelectricity. This finding inspires the possibility that such a planar quinary cluster may be useful in constructing many other endohedral fullerenes.

Study of the Inhibitory Effect of Water-Soluble Fullerenes on Plant Growth at the Cellular Level

The effect of water-soluble fullerene C(70)(C(COOH)(2))(4-8) on plant growth was investigated, using the transgenic seedling lines expressing fluorescent makers. The retarded roots with shortened length and loss of root gravitropism were observed for seedlings grown in the fullerene-containing medium. Fluorescence imaging revealed the abnormalities of root tips in hormone distribution, cell division, microtubule organization, and mitochondrial activity. The study of the inhibitory effects at the cellular level provides new information on the phytotoxicity mechanism of fullerene.

Structural Effect and Mechanism of C70‐Carboxyfullerenes as Efficient Sensitizers against Cancer Cells

Carboxyfullerenes with different adduct numbers and cage sizes are tested as photosensitizers for photodynamic therapy (PDT). The photodynamic efficiency of these carboxyfullerenes depends mainly on the cage size, C(60) versus C(70) , and to a lesser extent on the adduct numbers. In particular, malonic acid modified C(70) fullerenes are more efficient than their C(60) counterparts as photosensitizers, and the mechanism of cell death induced by C(70) -carboxyfullerene under light irradiation is investigated in detail. The results indicate that cell death occurs via necrosis accompanied by membrane blebbing, which is a unique phenomenon for photosensitizer-induced cell death. Since C(70) -carboxyfullerene displays an efficient PDT property and negligible dark cytotoxicity, it is promising for use in PDT applications, especially in vascular capillary diseases usually occurring under the surface.

Protective effect of C70-carboxyfullerene against oxidative-induced stress on postmitotic muscle cells.

Satellite muscle cells play an important role in regeneration of skeletal muscle. However, they are particularly vulnerable to oxidative stress. Herein, we address our efforts on the cytoprotective activities of carboxyfullerenes with different cage size (C60 vs C70) and adduct number on postmitotic muscle cell (C2C12 cell). The correlation of the structural effect on the cytoprotective capability of carboxyfullerenes was evaluated. We find that quadri-malonic acid C70 fullerene (QF70) exhibits higher capability on protecting cells from oxidative-induced stress among these tested carboxyfullerenes. The accumulation of intracellular superoxide dismutase (SOD) is proposed to play an important role in their diverse antioxidative ability. Moreover, the pretreatment of QF70 could also obviously enhance the viability of myotubes originated from oxidative-stressed C2C12 cells, which facilitates the future application of carboxyfullerenes in tissue engineering and nanomedicine.

Recent Progress of Molecular Imaging Probes Based on Gadofullerenes

Abstract Paramagnetic gadofullerenes and their derivatives exhibit more advantages than commercial Magnevist™ (Gd-DTPA) therefore have become competitive candidates for MR imaging probes. One of the most important properties is the stable fullerene cages are believed to hinder both chemical attacks on the inner clusters and the escape of the toxic lanthanide ions, which should effectively suppress the toxicity of naked Gd 3+ ions. Some functionalized gadofullerides are also available for further conjugation to fabricate multifunctional probes. This review presented the latest findings of MRI imaging probes based on various gadofullerenes, including Gd@C 60 , Gd@C 82 and Gd 3 N@C 80 and discussed the derivative strategy of gadofullerenes determining their relaxivity properties, biodistributions as well as their potential applications as nanoplatform for multifunctional probes.

Enhanced Photodynamic Efficiency of an Aptamer-Guided Fullerene Photosensitizer toward Tumor Cells

Fullerene-based photosensitizers exhibit great potential in photodynamic therapy (PDT). Based on the high photodynamic efficacy of trimalonic acid-modified C70 fullerene (TF70), we constructed an aptamer-guided TF70 photosensitizer and investigated its photodynamic effect. Conjugation of the novel aptamer (named R13) could effectively enhance the PDT efficiency of TF70 against A549 lung cancer cells in the presence of serum. The lysosomal location of the TF70-R13 conjugate inside cells facilitates the production of intracellular reactive oxygen species (ROS), which can efficiently kill cells, under light irradiation. The enhanced photodynamic efficiency, along with its good biocompatibility in the dark, makes TF70-R13 a highly promising photosensitizer for tumor-specific PDT.

C70-carboxyfullerenes as efficient antioxidants to protect cells against oxidative-induced stress.

Oxidative stress induced by excessive production of reactive oxygen species (ROS) has been implicated in the etiology of many human diseases. Acquiring a highly efficient antioxidant with good biocompatibility is of significance in eliminating the deleterious effect induced by the oxidative stress. Herein, we address our efforts on investigating the cytoprotective effect of carboxyfullerenes on H2O2-injured cells. Meanwhile, the uptake and intracellular location of carboxyfullerenes were studied. The results show that C70-carboxyfullerenes (dimalonic acid C70 fullerene (DF70) and trimalonic acid C70 fullerene (TF70)) exhibit an obviously protective effect against oxidative stress on C2C12 cells at concentrations as low as 2.5 μmol L(-1), whereas C60-carboxyfullerenes (dimalonic acid C60 fullerene (DF60) and quadri-malonic acid C60 fullerene (QF60)) show a protective effect at relatively higher concentration (40 μmol L(-1)). The molecular structure of carboxyfullerenes and the physiological state of cells play an important role in the different cytoprotective capability. Further study reveals that DF70 and TF70 could enter into cells and mainly localize into the lysosome, which possibly involves the protective mechanism by stabilizing lysosome. The use of a significantly low concentration of C70-carboxyfullerene as the antioxidative agent will benefit the therapeutic approaches aiming at alleviating ROS-induced injuries such as muscle disorder and arthritis.