A gadofullerene based liver-specific MRI contrast agent for an early diagnosis of orthotopic hepatocellular carcinoma.

Hepatocellular carcinoma has become one of the most prevalent cancers, with a high mortality rate. Accurate diagnosis at an earlier stage is regarded as an effective measure to reduce the disease-related mortality of liver cancer. Magnetic resonance imaging (MRI) as a non-invasive checking mode has become a powerful tool in medical diagnosis. However, MRI contrast agents for liver-specific imaging either have some side effects or the imaging effect is not ideal. Thus, development of more efficient and security MRI contrast agents for the early diagnosis of hepatocellular carcinoma is urgent. Herein, a kind of water-soluble gadofullerene nanoparticle (GFNP) with high efficiency and security has been successfully used to achieve in situ liver cancer imaging. By comparing GFNPs with different functional groups, Gd@C82 modified by a hydroxyl group (GF-OH) presents the highest contrast efficiency both in vitro and in vivo. Notably, the smallest tumor with a diameter of only 0.5 mm could be clearly observed by GF-OH using MRI. Moreover, the imaging window of GF-OH is more than 3-6 hours. In addition, GF-OH can be mostly excreted from the living body and causes no serious toxicity. These results demonstrate that GF-OH is a safe, efficient MRI contrast agent for the diagnosis of early orthotopic hepatocellular carcinoma.

Characterization and Cytotoxicity of Polyprenol Lipid and Vitamin E-TPGS Hybrid Nanoparticles for Betulinic Acid and Low-Substituted Hydroxyl Fullerenol in MHCC97H and L02 Cells.

BACKGROUND: This study demonstrated an innovative formulation including the polyprenol (GBP) lipid and vitamin E-TPGS hybrid nanoparticles (NPs) which was aimed to control the transfer of betulinic acid (BA) and low-substituted hydroxyl fullerenol (C60(OH)n). Additionally, it developed BA-C60(OH)n-GBP-TPGS-NPs delivery system and researched the anti-hepatocellular carcinoma (HCC) effects. MATERIALS AND METHODS: The NPs were prepared by nanoprecipitation with ultrasonic-assisted emulsification (UAE) method. It was characterized by scanning electronic microscopy (SEM), transmission electron microscopy (TEM), FTIR spectrum, size distribution and zeta potential. Physical and chemical properties were evaluated through measurement of drug release, stability studies, drug loading efficiency (DE) and encapsulation efficiency (EE). Biological activities were evaluated through measurement of MTT assay, lactate dehydrogenase leakage assay (LDH), cell proliferation assays, cell apoptosis analysis, comet assay, wound healing assay, cell invasion and Western blot analysis. RESULTS AND CONCLUSIONS: The NPs exhibited clear distribution characteristics, improved solubility and stability. BA and C60(OH)n for the NPs displayed a biphasic release pattern with sustained drug release properties. The mixture of C60(OH)n with different hydroxyl groups may have a certain effect on the stability of the NPs system itself. The NPs could effectively inhibit MHCC97H cell proliferation, migration and invasion in vitro. Combined use of C60(OH)n and BA in GBP lipids may improve the inhibit effect of C60(OH)n or BA against HCC cells and reduce cytotoxicity and genotoxicity of C60(OH)n for normal cells. We concluded that one of the important mechanisms of BA-C60(OH)n-GBP-TPGS-NPs inhibiting MHCC97H cells is achieved by up-regulating the expression of Caspase-3, Caspase-8 and Caspase-9.

Aspartic acid derivatized hydroxylated fullerenes as drug delivery vehicles for docetaxel: an explorative study.

The objective of the present study was to deliver docetaxel to cancerous cells with enhanced efficacy and safety profile, using aspartic acid linked fullerenols. This aspartic acid derivatized fullerenol conjugate linked with docetaxel was characterized by UV, FT-IR and NMR spectroscopy. Studies for particle size, PDI, zeta potential and FE-SEM were also performed. The conjugate was evaluated for release kinetics, cancer cell cytotoxicity, cellular uptake using confocal laser microscopy and also for pharmacokinetic profile. Cytotoxic studies proved that there was almost 4.3 folds decrease in IC50 with significantly enhanced cellular uptake of the nanometric conjugates. It was observed that the bioavailability was enhanced by 5.8 folds when compared to that of pure DTX. The developed nanoconstructs were erythrocyte compatible and offered decreased protein binding. The findings are encouraging and offer a novel carrier with enhanced efficacy and safety of a drug, belonging to BCS class IV.

Biotransport kinetics and intratumoral biodistribution of malonodiserinolamide-derivatized [60]fullerene in a murine model of breast adenocarcinoma.

[60]Fullerene is a highly versatile nanoparticle (NP) platform for drug delivery to sites of pathology owing to its small size and both ease and versatility of chemical functionalization, facilitating multisite drug conjugation, drug targeting, and modulation of its physicochemical properties. The prominent and well-characterized role of the enhanced permeation and retention (EPR) effect in facilitating NP delivery to tumors motivated us to explore vascular transport kinetics of a water-soluble [60]fullerene derivatives using intravital microscopy in an immune competent murine model of breast adenocarcinoma. Herein, we present a novel local and global image analysis of vascular transport kinetics at the level of individual tumor blood vessels on the micron scale and across whole images, respectively. Similar to larger nanomaterials, [60]fullerenes displayed rapid extravasation from tumor vasculature, distinct from that in normal microvasculature. Temporal heterogeneity in fullerene delivery to tumors was observed, demonstrating the issue of nonuniform delivery beyond spatial dimensions. Trends in local region analysis of fullerene biokinetics by fluorescence quantification were in agreement with global image analysis. Further analysis of intratumoral vascular clearance rates suggested a possible enhanced penetration and retention effect of the fullerene compared to a 70 kDa vascular tracer. Overall, this study demonstrates the feasibility of tracking and quantifying the delivery kinetics and intratumoral biodistribution of fullerene-based drug delivery platforms, consistent with the EPR effect on short timescales and passive transport to tumors.

Positron emission tomography (PET) guided glioblastoma targeting by a fullerene-based nanoplatform with fast renal clearance.

Various carbonaceous nanomaterials, including fullerene, carbon nanotube, graphene, and carbon dots, have attracted increasing attention during past decades for their potential applications in biological imaging and therapy. In this study, we have developed a fullerene-based tumor-targeted positron emission tomography (PET) imaging probe. Water-soluble functionalized C60 conjugates were radio-labeled with 64Cu and modified with cyclo (Arg-Gly-Asp) peptides (cRGD) for targeting of integrin αvß3 in glioblastoma. The specificity of fluorescein-labeled C60 conjugates against cellular integrin αvß3 was evaluated in U87MG (integrin αvß3 positive) and MCF-7 cells (integrin αvß3 negative) by confocal fluorescence microscopy and flow cytometry. Our results indicated that cRGD-conjugated C60 derivatives showed better cellular internalization compared with C60 derivatives without the cRGD attachment. Moreover, an interesting finding on intra-nuclei transportation of cRGD-conjugated C60 derivatives was observed in U87MG cells. In vivo serial PET studies showed preferential accumulation of cRGD-conjugated C60 derivatives at in U87MG tumors. In addition, the pharmacokinetic profiles of these fullerene-based nanoparticles conjugated with cRGD and 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) fit well with the three compartment model. The renal clearance of C60-based nanoparticles is remarkably fast, which makes this material very promising for safer cancer theranostic applications. STATEMENT OF SIGNIFICANCE: Safety is one of the major concerns for nanomedicine and nanomaterials with fast clearance profile are highly desirable. Fullerene is a distinct type of zero-dimensional carbon nanomaterial with ultrasmall size, uniform dispersity, and versatile reactivity. Here we have developed a fullerene-based tumor-targeted positron emission tomography imaging probe using water-soluble functionalized C60 conjugates radio-labeled with 64Cu and modified with cyclo (Arg-Gly-Asp) peptides (cRGD) for glioblastoma targeting. The improved tumor targeting property along with fast renal clearance behavior of C60-based nanoparticles makes this material very promising for future safer cancer theranostic applications.

Visible light-switched cytosol release of siRNA by amphiphilic fullerene derivative to enhance RNAi efficacy in vitro and in vivo.

Cationic macromolecules are attractive for use as small interfering RNA (siRNA) carriers due to their performance in non-immunological reactions, customization during synthesis, and low costs compared to viral carriers. However, their low transfection efficiency substantially hinders their application in both clinical practices and academic research, which is mostly attributable to the low capacity of siRNA/cationic macromolecule complexes to escape lysosomes. To address this challenge, we designed an amphiphilic fullerene derivative (C60-Dex-NH2) for efficient and controllable siRNA delivery. To synthesize C60-Dex-NH2, terminally aminated dextran was conjugated to C60. The conjugate was further cationized by covalently introducing ethylenediamine to the dextran. The physicochemical characteristics of C60-Dex-NH2 was examined with elemental analyses, gel permeation chromatography, solid-state nuclear magnetic resonance (13C, HPDEC), agarose gel electrophoresis, and dynamic light scattering. The cytotoxicity, cellular uptake, intracellular distribution, and in vitro RNA interference (RNAi) of siRNA/C60-Dex-NH2 complex was evaluated in the human breast cancer cell line MDA-MB-231. The RNAi efficiencies mediated by C60-Dex-NH2in vivo was evaluated in subcutaneous tumor-bearing mice. The results showed that C60-Dex-NH2 has a specific amphiphilic skeleton and could form micelle-like aggregate structures in water, which could prevent siRNA from destroying by reactive oxygen species (ROS). When exposed to visible light, C60-Dex-NH2 could trigger controllable ROS generation which could destroy the lysosome membrane, promote the lysosomal escape, and enhance the gene silencing efficiency of siRNA in vitro and in vivo. The gene silencing efficiency could reach a maximum of 53% in the MDA-MB-231-EGFP cells and 69% in the 4T1-GFP-Luc2 tumor-bearing mice. STATEMENT OF SIGNIFICANCE: We designed a novel photosensitive amphiphilic carrier (C60-Dex-NH2) for efficient and controllable siRNA delivery, which can be used in gene therapy. We showed that C60-Dex-NH2 could destroy lysosome membrane via controllable generation of ROS when exposed to light, which can help siRNA to escape from lysosome before degradation. This can enhance the gene silencing efficiency significantly and provides a useful way to regulate RNAi efficiency by light. One advantage for C60-Dex-NH2 system is C60 has broad absorbance spectrum and can be activated by weak visible light; Furthermore, C60-Dex-NH2 has a specific amphiphilic structure, which may prevent siRNA from degrading and allows C60-Dex-NH2 to embed into the lipid membrane of lysosome to improve the ROS induced lysosomal disturbance after internalization.

The effects of non-invasive radiofrequency electric field hyperthermia on biotransport and biodistribution of fluorescent [60]fullerene derivative in a murine orthotopic model of breast adenocarcinoma.

The aim of this study is to understand the combined and differential biokinetic effects of radiofrequency (RF) electric-field hyperthermia as an adjunctive therapy to [60]fullerene nanoparticle-based drug delivery systems in targeting the micro-vasculature and micro-environments of breast cancer tumors. Intravital microscopy (IVM) is an ideal tool to provide the spatial and temporal resolution needed for quantification in this investigation. The water-soluble and fluorescent [60]fullerene derivative (C60-serPF) was designed to be an amphiphilic nanostructure, which is able to cross several biological membranes and accumulate in tumor tissues by passing through abnormally leaky tumor blood vessels. To elucidate the coupled effects of the highly permeable, but heterogeneous tumor vasculature, with the permeabilizing effects of mild (40-42°C) hyperthermia produced by a local RF field, we controlled variables across tumor and non-tumor mammary gland microvasculature with and without application of RF hyperthermia in each condition. We notice that tumor tissue is characterized by more intense drug extravasation than in contralateral mammary fat pad tissue, which is consistent with enhanced permeability and retention (EPR) effects. The analysis of a permeability parameter (Papp), C60-serPF velocity, and the time of compound influx into the intra- and extra-vascular space suggest that mild RF hyperthermia can improve nanoparticle delivery into tumor tissue.

Aminated carbon-based "cargo vehicles" for improved delivery of methotrexate to breast cancer cells.

The purpose of study was to conjugate and evaluate methotrexate with C60-fullerenes and multi-walled carbon nanotubes (MWCNTs) for better drug delivery to cancer cells, and also to compare these two systems. C60-fullerenes and MWCNTs were functionalized by 1,3-dipolar cycloaddition using glycine and paraformaldehyde. Methotrexate (MTX) was esterified and conjugated to the functionalized carbon-based carriers. The conjugates were characterized for micromeritics and drug conjugation. The systems were evaluated for drug release in various pH, MTT cytotoxicity assay, protein binding, cellular uptake, haemolytic profile and pharmacokinetics. Spectroscopic studies confirmed the successful conjugation of drug to the aminated carbon-based carriers. The developed systems released more drug at the pH of cancer cells to that of the pH of plasma. The carriers were compatible with erythrocytes and offered substantial cytotoxicity. Better cellular uptake was confirmed by confocal laser scanning microscopy. C60-fullerenes/MWCNTs modulated the pharmacokinetic profile of drug in desired manner, resulting in better retention and compartment availability. However, the results from C60-fullerenes were observed to be better than that from MWCNTs. The present findings established the potential of carbon-based aminated nanocarriers for delivery of methotrexate in safer and effective manner.

Development of Gd3N@C80 encapsulated redox nanoparticles for high-performance magnetic resonance imaging.

As novel magnetic resonance imaging (MRI) contrast agent, gadofullerene encapsulated redox nanoparticles (Gd3NPs) were prepared by encapsulation of Gd3N@C80 in the core of core-shell-type polymer micelles composed of original polyamine with a reactive oxygen species (ROS)-scavenging ability. Because Gd3NPs possess biocompatible PEG shell with a smaller size (ca. 50 nm), they had high colloidal stability in a physiological environment, and showed low cytotoxicity. Specific accumulation of Gd3NPs in a tumor was confirmed in tumor-bearing mice after systemic administration. The tumor/muscle (T/M) ratio of the Gd ion reached five at 7.5 h after the administration. T1-weighted MRI signal enhancement of the T/M ratio increased by 8% at 6 h postinjection of Gd3NPs (Gd dose:14.35 µmol/kg). Although Gd3NPs showed a tendency for extended blood circulation, they did not have severe adverse effects, probably due to the confinement of Gd in a hydrophobic fullerene in addition to the ROS-scavenging capacity of these nanoparticles. In sharp contrast, systemic administration of Gd-chelate nanoparticles (GdCNPs) to mice disrupts liver function, increases leukocyte counts, and destroys spleen and skin tissues. Leaking of Gd ions from GdCNPs may cause such adverse effects. Based on these results, we expect that Gd3NPs is high-performance MRI contrast agents for tumor diagnosis.

Enhanced brain penetration of hexamethonium in complexes with derivatives of fullerene C60.

The present report describes development of hexamethonium complexes based on fullerene C60. Hexamethonium has a limited penetration into CNS and therefore can antagonize central effects of nicotine only when given at high doses. In the present studies conducted in laboratory rodents, intraperitoneal administration of hexamethonium-fullerene complexes blocked effects of nicotine (convulsions and locomotor stimulation). When compared to equimolar doses of hexamethonium, complexes of hexamethonium with derivatives of fullerene C60 were 40 times more potent indicating an enhanced ability to interact with central nicotine receptors. Thus, fullerene C60 derivatives should be explored further as potential carrier systems for polar drug delivery into CNS.

Fullerene (C60)-based tumor-targeting nanoparticles with "off-on" state for enhanced treatment of cancer.

The traditional drug delivery systems always suffer from the unexpected drug release during circulation and the sluggish release of drug in target site. To address the problem, an "off-on" type drug delivery system with precise control was developed in this study. Doxorubicin (DOX) was covalently conjugated to fullerene (C60) nanoaggregates via a reactive oxygen species (ROS)-sensitive thioketal linker (C60-DOX NPs), and then the hydrophilic shell (Distearoyl-sn-glycero-3-phosphoethanolamine-PEG-CNGRCK2HK3HK11, DSPE-PEG-NGR) was attached to the outer surface of C60-DOX, giving it (C60-DOX-NGR NP) excellent stability in physiological solutions and active tumor-targeting capacity. C60-DOX-NGR NPs were able to entrap DOX efficiently even at acidic environment (pH5.5) when they were "off" state. In sharp contrast, when the NPs were "on" state, a large number of ROS were generated by C60, leading to the breaking of ROS-sensitive linker, thereby enabling the burst release of DOX. The "off" or "on" state of C60-DOX-NGR NPs could be precisely remote-controlled by a 532nm laser (at a low power density) with a high spatial/temporal resolution. In the in vivo and in vitro studies, the C60-based drug delivery system with "off-on" state exhibited a high antitumor efficacy and a low toxicity to normal tissues due to its tumor-targeting ability, remote-controlled drug release property and combined therapeutic effect (photodynamic therapy combined with chemotherapy).

A tumor-specific cleavable nanosystem of PEG-modified C60@Au hybrid aggregates for radio frequency-controlled release, hyperthermia, photodynamic therapy and X-ray imaging.

Taking advantages of fullerene (C60) and gold nanoparticles (AuNPs) for potentials in photodynamic therapy (PDT), drug delivery and radio frequency thermal therapy (RTT), a C60@Au hybrid nanocomposite was synthesized by chemical deposition of Au nanoparticles onto C60, and functionalized by PEG5000 via a pH cleavable hydrazone bond, making C60@Au-PEG keep the PEG on the surface of drug delivery system during circulation but dissociate PEG from the system after accumulation in tumor tissue, then doxorubicin (DOX) was loaded onto C60@Au-PEG with a very high drug loading efficiency. The release profiles of DOX from C60@Au-PEG/DOX showed strong dependences on radio frequency (RF). For the drug delivery, C60@Au-PEG/DOX afforded much higher antitumor efficacy owing to 8.6-fold higher DOX uptake of tumor than DOX. Besides, in this work, C60@Au-PEG/DOX not only served as a powerful RTT agent for RF-thermal ablation of tumor and a strong photosensitizer (PS) for PDT, but also as an X-ray contrast agent for tumor diagnosis. In the in vitro and in vivo studies, C60@Au-PEG/DOX showed excellent chemo-RF thermal-photodynamic therapeutic efficacy, RF-controlled drug releasing function, tumor targeting property, tumoral acid PEG dissociating character and X-ray imaging ability, demonstrating that there is a great potential of C60@Au-PEG/DOX for simultaneous diagnosis and therapy in cancer treatment. STATEMENT OF SIGNIFICANCE: A significant challenge in cancer therapy is to maximize the therapeutic efficacy and minimize the side effects. In the past decade, a lot of nanoparticles have been used as the carriers for efficient drug delivery. However, the design of drug delivery system (DDS) with stimuli-responsive controlled-release property, simultaneous diagnosis and therapy functions is still a challenge. Herein, we developed a new drug delivery system (C60@Au-PEG/DOX), and explored its applications in tumor therapy. The in vitro and in vivo results showed C60@Au-PEG/DOX could significantly improve the therapeutic efficacy and reduce the systemic toxicity through X-ray imaging guided locatable DOX release, photodynamic and photothermal therapies. These results are of interest as they demonstrate a multi-functional DDS for tumor theranostic applications.

Fullerene as a transporter for doxorubicin investigated by analytical methods and in vivo imaging.

Carbon nanomaterials, including fullerenes, exhibit not only unique structure and electronic properties but also a significant potential to serve as radical scavengers and/or anti-oxidants. Their conjugation with anticancer drugs such as doxorubicin (DOX) may help to balance severe negative side effects of these cytostatics and also improve the delivery of the drug taking advantage of the enhanced cellular uptake, selectivity to cancer cells, and pH regulated release. In this study, the fullerene (C60) surface was oxidized by concentrated nitric acid, which enabled simple DOX-fullerene conjugation based on π-π stacking and hydrophilic interactions with carboxylic groups. The strength of this noncovalent binding is pH dependent. At a low pH, the amino group of DOX is protonated, however at a higher pH, the amino group is deprotonated, resulting in stronger hydrophobic interactions with the fullerene walls. CE and HPLC were employed for characterization of resulting complexes. The cell toxicity of the conjugates was evaluated using Staphylococcus aureus and finally they were administered into the chicken embryo to assess the applicability for in vivo imaging.

A novel gadolinium-based trimetasphere metallofullerene for application as a magnetic resonance imaging contrast agent.

OBJECTIVE: Macromolecular contrast agents for magnetic resonance imaging (MRI) are useful blood-pool agents because of their long systemic half-life and have found applications in monitoring tumor vasculature and angiogenesis. Macromolecular contrast agents have been able to overcome some of the disadvantages of the conventional small-molecule contrast agent Magnevist (gadolinium-diethylenetriaminepentaacetic acid), such as rapid extravasation and quick renal clearance, which limits the viable MRI time. There is an urgent need for new MRI contrast agents that increase the sensitivity of detection with a higher relaxivity, longer blood half-life, and reduced toxicity from free Gd3+ ions. Here, we report on the characterization of a novel water-soluble, derivatized, gadolinium-enclosed metallofullerene nanoparticle (Hydrochalarone-1) in development as an MRI contrast agent. MATERIALS AND METHODS: The physicochemical properties of Hydrochalarone-1 were characterized by dynamic light scattering (hydrodynamic diameter), atomic force microscopy (particle height), ζ potential analysis (surface charge), and inductively coupled plasma-mass spectrometry (gadolinium concentration). The blood compatibility of Hydrochalarone-1 was also assessed in vitro through analysis of hemolysis, platelet aggregation, and complement activation of human blood. In vitro relaxivities, in vivo pharmacokinetics, and a pilot in vivo acute toxicity study were also performed. RESULTS: An extensive in vitro and in vivo characterization of Hydrochalarone-1 is described here. The hydrodynamic size of Hydrochalarone-1 was 5 to 7 nm depending on the dispersing media, and it was negatively charged at physiological pH. Hydrochalarone-1 showed compatibility with blood cells in vitro, and no significant hemolysis, platelet aggregation, or complement activation was observed in vitro. In addition, Hydrochalarone-1 had significantly higher r1 and r2 in vitro relaxivities in human plasma in comparison with Magnevist and was not toxic at the doses administered in an in vivo pilot acute-dose toxicity study in mice.In vivo MRI pharmacokinetic analysis after a single intravenous injection of Hydrochalarone-1 (0.2 mmol Gd/kg) showed that the volume of distribution at steady state was approximately 100 mL/kg, suggesting prolonged systemic circulation. Hydrochalarone-1 also had a long blood half-life (88 minutes) and increased relaxivity, suggesting application as a promising blood-pool MRI contrast agent. CONCLUSIONS: The evidence suggests that Hydrochalarone-1, with its long systemic half-life, may have significant utility as a blood-pool MRI contrast agent.

Photodynamic therapy of a 2-methoxyestradiol tumor-targeting drug delivery system mediated by Asn-Gly-Arg in breast cancer.

Fullerene (C60) has shown great potential in drug delivery. In this study we exploited modified fullerene (diadduct malonic acid-fullerene-Asn-Gly-Arg peptide [DMA-C60-NGR]) as an antitumor drug carrier in order to build a new tumor-targeting drug delivery system. We also investigated the synergistic enhancement of cancer therapy using photodynamic therapy (PDT) induced by DMA-C60-NGR and 2-methoxyestradiol (2ME). Cytotoxicity tests indicated that DMA-C60-NGR had no obvious toxicity, while our drug delivery system (DMA-C60-2ME-NGR) had a high inhibition effect on MCF-7 cells compared to free 2ME. The tumor-targeting drug delivery system could efficiently cross cell membranes, and illumination induced the generation of intracellular reactive oxygen species and DNA damage. Furthermore, DMA-C60-2ME-NGR with irradiation had the highest inhibition effect on MCF-7 cells compared to the other groups. DMA-C60-NGR combined with 2ME showed a good synergistic photosensitization effect for inhibiting the growth of MCF-7 cells, demonstrating that DMA-C60-2ME-NGR may be promising for high treatment efficacy with minimal side effects in future therapy.

PEI-derivatized fullerene drug delivery using folate as a homing device targeting to tumor.

Fullerene (C60) has shown great potential in drug delivery. In this study, firstly, amine-functionalized C60 (C60-NH(2)) was achieved by introducing ethylenediamine onto the surface of C60, and then PEI-derivatized C60 (C60-PEI) was performed via a cationic polymerization of aziridine on the surface of C60-NH(2); FT-IR and TGA results verified the structure of water-soluble C60-PEI. C60-PEI was encapsulated with folic acid (FA) through an amide linker, and then docetaxel (DTX) was conjugated to C60-PEI-FA and obtained a drug delivery system, C60-PEI-FA/DTX. Compared with free DTX, the tumor targeting drug delivery could efficiently cross cell membranes, lead to more apoptosis and afford higher antitumor efficacy in a cultured PC3 cells in vitro. Furthermore, compared with free DTX in an in vivo murine tumor model, C60-PEI-FA/DTX afforded higher antitumor efficacy without obvious toxic effects to normal organs owing to its prolonged blood circulation and 7.5-fold higher DTX uptake of tumor, demonstrating that C60-PEI-FA/DTX may be promising for high treatment efficacy with minimal side effects in future therapy.

The prolongation of the lifespan of rats by repeated oral administration of [60]fullerene.

Countless studies showed that [60]fullerene (C(60)) and derivatives could have many potential biomedical applications. However, while several independent research groups showed that C(60) has no acute or sub-acute toxicity in various experimental models, more than 25 years after its discovery the in vivo fate and the chronic effects of this fullerene remain unknown. If the potential of C(60) and derivatives in the biomedical field have to be fulfilled these issues must be addressed. Here we show that oral administration of C(60) dissolved in olive oil (0.8 mg/ml) at reiterated doses (1.7 mg/kg of body weight) to rats not only does not entail chronic toxicity but it almost doubles their lifespan. The effects of C(60)-olive oil solutions in an experimental model of CCl(4) intoxication in rat strongly suggest that the effect on lifespan is mainly due to the attenuation of age-associated increases in oxidative stress. Pharmacokinetic studies show that dissolved C(60) is absorbed by the gastro-intestinal tract and eliminated in a few tens of hours. These results of importance in the fields of medicine and toxicology should open the way for the many possible -and waited for- biomedical applications of C(60) including cancer therapy, neurodegenerative disorders, and ageing.

Fullerenes for cancer diagnosis and therapy: preparation, biological and clinical perspectives.

Cancer is a major public health problem in the world. There is a great need to apply novel technologies and drugs to revolutionize multiple aspects of cancer diagnosis and therapy. Advances in nanotechnology and nanomaterials have the potential to achieve the objective of early diagnosis and early therapy of cancer in the future. During the past few years, fullerene and its derivatives have been considered as some of the most promising nanomaterials because of their unique properties that enable a variety of medicinal applications. They can deliver drugs or small therapeutic molecules to the cancer cells. In this review, we will discuss how fullerene derivatives have been introduced into the field of cancer diagnosis and therapy. It will be highlighted that fullerene derivatives are used as anti-tumor drugs. Furthermore, preparation, characterization, pharmacokinetics and bio-distribution of fullerene and its derivatives reported in recent years will be summarized.

Biosafety assessment of Gd@C82(OH)22 nanoparticles on Caenorhabditis elegans.

Gd@C(82)(OH)(22), a water-soluble endohedral metallofullerene derivative, has been proven to possess significant antineoplastic activity in mice. Toxicity studies of the nanoparticle have shown some evidence of low or non toxicity in mice and cell models. Here we employed Caenorhabditis elegans (C. elegans) as a model organism to further evaluate the short- and long-term toxicity of Gd@C(82)(OH)(22) and possible behavior changes under normal and stress culture conditions. With treatment of Gd@C(82)(OH)(22) at 0.01, 0.1, 1.0 and 10 µg ml(-1) within one generation (short-term), C. elegans showed no significant decrease in longevity or thermotolerance compared to the controls. Furthermore, when Gd@C(82)(OH)(22) treatment was extended up to six generations (long-term), non-toxic effects to the nematodes were found. In addition, data from body length measurement, feeding rate and egg-laying assays with short-term treatment demonstrated that the nanoparticles have no significant impact on the individual growth, feeding behavior and reproductive ability, respectively. In summary, this work has shown that Gd@C(82)(OH)(22) is tolerated well by worms and it has no apparent toxic effects on longevity, stress resistance, growth and behaviors that were observed in both adult and young worms. Our work lays the foundations for further developments of this anti-neoplastic agent for clinical applications.

Subcellular distribution of polyhydroxylated metallofullerene Gd@C82(OH)22 in different tissues of tumor-bearing mice.

Endohedral metallofullerenes have unique chemical and physical properties that are essential for biomedical applications. They can be used as a radiotracer in magnetic resonance and X-ray imaging (MRI and XRI). Polyhydroxylated metallofullerene Gd@C82(OH)x has been studied as a new high efficient contrast agents for MRI and has also shown high efficiency for antitumor growth. Previous studies have shown that Gd@C82(OH)22 mainly accumulated in bone, pancreas, liver and kidney after intraperitoneal administration. However, whether the nanoparticles can enter into cells and the site of their potential action remains unclear. In this work, the distribution patterns of Gd@C82(OH)22 in subcellular compartments were studied using the techniques of differential centrifugation and ICP-MS analysis. The results indicate that the Gd@C82(OH)22 can enter into cells and the subcellular distribution patterns are significantly different from that of GdCl3. GdCl3 has much higher bioavailability for mice than Gd@C82(OH)22. Therefore, the present data suggest that Gd@C82(OH)22 in living systems may be not decomposed to release free Gd3+ ion and may be metabolized as a pristine carbon cage.