Characterization of C60 fullerene complexation with antibiotic doxorubicin

C60 Fullerene Clusters Stabilize the Biologically Inactive Form of Topotecan

There is a range of experimental proofs that biologically relevant compounds change their activity in the presence of C₆₀ fullerene clusters in aqueous solution, which most frequently act as a nanoplatform for drug delivery. Inspired by this evidence, we made an effort to investigate the interaction of fullerene clusters with the antibiotic topotecan (TPT). This study proceeded in three steps, namely, UV/vis titration to confirm complexation and in vitro assays on proliferating and nonproliferating cells to elucidate the role of C₆₀ fullerene in the putative change in TPT activity. Surprisingly, although the nonproliferating cell assay is consistent with the titration data and confirms complex formation, it contradicted the results of the proliferating cell assay. The latter showed that the mixture of TPT and fullerene affects the cells in the same way as pure TPT, as if there were no fullerenes in solution at all, whereas the action of TPT was expected to be enhanced. We explained this contradiction by the specific stabilization of the biologically inactive carboxylate form of the antibiotic adsorbed in the alkaline shell of large fullerene clusters, which leads to neutralization of the drug delivery function and almost zero net biological effect of the antibiotic in vitro. The practical outcome of the work is that fullerene clusters can be used for the selective delivery of pH-sensitive drug forms.

C60-β-cyclodextrin conjugates for enhanced nucleus delivery of doxorubicin

We demonstrate the use of water-soluble C₆₀-β-cyclodextrin conjugates to encapsulate and deliver doxorubicin to the cell nucleus. The behaviour of the fullerene aggregates inside cells is dictated by the functionalization of the C₆₀ cage. While both the C₆₀ conjugates are taken up by lysosomes upon cellular entry, only the one with a hydroxylated cage rapidly escaped the lysosome. The drug delivery system (DDS) with a hydroxylated C₆₀ cage showed significantly enhanced doxorubicin delivery to the cell nucleus, whereas the DDS with a hydrophobic C₆₀ cage was trapped in the lysosome for a longer time and showed significantly reduced doxorubicin delivery to the nucleus. This study opens new paths towards advanced fullerene-based DDSs for small molecule drugs.

The Impact of Fullerenes as Doxorubicin Nano-Transporters on Metallothionein and Superoxide Dismutase Status in MCF-10A Cells

This study aimed to synthesise C₆₀–DOX complexes followed by the analysis of their effect on the concentration of metallothionein (MT) as a non-enzymatic antioxidant and on the concentration and activity of superoxide dismutase (SOD) as an antioxidant enzyme in healthy human mammary MCF-10A cells. Dynamic light scattering and electrophoretic light scattering were used to establish the size and zeta potential of the complexes. The MT and SOD concentrations were determined using the ELISA method; SOD activity was determined by tetrazolium salt reduction inhibition. Lower MT concentration following exposure of cells to both DOX and C₆₀ fullerene compared to the control sample was found. However, the concentration of this protein increased as a consequence of the C₆₀–DOX complexes action on MCF-10A cells compared to the control. C₆₀ used alone did not affect the concentration and activity of SOD in MCF-10A cells. Application of free DOX did not activate cellular antioxidant defence in the form of an increase in SOD concentration or its activity. In contrast treatment of cells with the C₆₀–DOX complex resulted in a decrease in SOD1 concentration and a significant increase in SOD activity compared to cells treated with free DOX, C₆₀ and control. Thus, it was found that C₆₀–DOX complexes showed potential for protective effects against DOX-induced toxicity to MCF-10A cells.

Nanoantibiotics: Functions and Properties at the Nanoscale to Combat Antibiotic Resistance

One primary mechanism for bacteria developing resistance is frequent exposure to antibiotics. Nanoantibiotics (nAbts) is one of the strategies being explored to counteract the surge of antibiotic resistant bacteria. nAbts are antibiotic molecules encapsulated with engineered nanoparticles (NPs) or artificially synthesized pure antibiotics with a size range of ≤100 nm in at least one dimension. NPs may restore drug efficacy because of their nanoscale functionalities. As carriers and delivery agents, nAbts can reach target sites inside a bacterium by crossing the cell membrane, interfering with cellular components, and damaging metabolic machinery. Nanoscale systems deliver antibiotics at enormous particle number concentrations. The unique size-, shape-, and composition-related properties of nAbts pose multiple simultaneous assaults on bacteria. Resistance of bacteria toward diverse nanoscale conjugates is considerably slower because NPs generate non-biological adverse effects. NPs physically break down bacteria and interfere with critical molecules used in bacterial processes. Genetic mutations from abiotic assault exerted by nAbts are less probable. This paper discusses how to exploit the fundamental physical and chemical properties of NPs to restore the efficacy of conventional antibiotics. We first described the concept of nAbts and explained their importance. We then summarized the critical physicochemical properties of nAbts that can be utilized in manufacturing and designing various nAbts types. nAbts epitomize a potential Trojan horse strategy to circumvent antibiotic resistance mechanisms. The availability of diverse types and multiple targets of nAbts is increasing due to advances in nanotechnology. Studying nanoscale functions and properties may provide an understanding in preventing future outbreaks caused by antibiotic resistance and in developing successful nAbts.

Green and rapid preparation of long-term stable aqueous dispersions of fullerenes and endohedral fullerenes: The pros and cons of an ultrasonic probe

A green, scalable, and sustainable approach to prepare aqueous fullerene dispersions (AFD) C60, C70, endohedral metallofullerene Gd@C82, and their derivatives C60Cl6, C70Cl10, and supramolecular and ester-like derivatives, 10 fullerene species total, is proposed. For the first time, an immersed ultrasonic probe was used to preparing dispersions for pristine fullerenes without addends. Both ultrasound-assisted solvent-exchange and direct sonication techniques for AFD preparation using an immersed probe were tested. The average time for AFD preparation decreases 10-15 times compared to an ultrasound-bath-assisted technique, while final fullerene concentrations in AFDs remained at tens of ppm (up to 80 ppm). The aqueous dispersions showed long-term stability, a negatively charged surface with a zeta potential up to -32 mV with an average nanocluster diameter of no more than 180 nm. The total anionic and cationic compositions of samples were found by inductively coupled plasma atomic emission spectroscopy and chromatographic techniques. The highlights and challenges of using an ultrasound probe for AFD production are discussed.

C60 Fullerene Governs Doxorubicin Effect on Metabolic Profile of Rat Microglial Cells In Vitro

Background: C₆₀ fullerenes and their derivatives are actively investigated for the use in neuroscience. Applications of these nanoscale materials require the examination of their interaction with different neural cells, especially with microglia, because these cells, like other tissue resident phagocytes, are the earliest and most sensitive responders to nanoparticles. The aim of this study was to investigate the effect of C₆₀ fullerene and its nanocomplex with doxorubicin (Dox) on the metabolic profile of brain-resident phagocytes-microglia-in vitro. Methods: Resting microglial cells from adult male Wistar rats were used in experiments. Potential C₆₀ fullerene targets in microglial cells were studied by computer simulation. Microglia oxidative metabolism and phagocytic activity were examined by flow cytometry. Griess reaction and arginase activity colorimetric assay were used to explore arginine metabolism. Results: C₆₀ fullerene when used alone did not influence microglia oxidative metabolism and phagocytic activity but shifted arginine metabolism toward the decrease of NO generation. Complexation of C₆₀ fullerene with Dox (C₆₀-Dox) potentiated the ability of the latter to stimulate NO generation. Conclusion: The capability of C₆₀ fullerenes used alone to cause anti-inflammatory shift of microglia arginine metabolism makes them a promising agent for the correction of neuroinflammatory processes involved in neurodegeneration. The potentiating action of C₆₀ fullerene on the immunomodulatory effect of Dox allows us to consider the C₆₀ molecule as an attractive vehicle for this antitumor agent.

Azomethine ylide addition impact on functionalized [60]Fullerene and [60]Boron-Nitride: Anticancer Doxorubicin and Boronic Chalcone drugs binding characteristics with mono- and bis-nanocarriers

By functionalizing [60]Fullerene (C60) and [60]Boron-Nitride ([60]BN), novel systems are proposed under two alternatives according to the intruder localization modes. To detail their bindings with Doxorubicin (DOX) and Boronic Chalcone (BCHA), we studied the azomethine ylide (AZMYtrp and AZMYtyr) addition impact on the drug-loading efficacy. As a result, the formation of reactive [60]CBNAZMYtrp nanocarriers mainly proceeded through photoexcitation on the triplet state, in contrast to those of [60]BNCAZMYtrp. The addition of amino acids strongly improved the interaction between DOX/BCHA and mono- and bis-nanocarriers compared to isolated anticancer drugs randomly dispersed in the solvent. Eight possible bis-nanocarriers regioisomers are cheeked for the second AZMYtrp addition sites. In fact, the trans1 isomer is considered as the most stable to adsorb DOX-DOX, DOX-BCHA or BCHA-BCHA with mole fraction of about 84 %. The lowest electronic bandgap (0.529 eV) of B25N25C10AZMYtyrAZMYtyr confirmed that the presence of hydrogen-bonding and OH-π, CH-π and CO-π interactions improved the binding affinity of bis-nanocarriers with DOX-DOX. The AZMYtrp indole ring hydrogen is bonded with the anticancer drug hydroxyl group and stabilized DOX-DOX-bis-nanocarriers complexes. The formation of new sp³ regions and π-π interactions with the carbon-doped [60]BN decreased the bandgap (0.64 eV) and stabilized the B25N25C10AZMYtyrAZMYtyr-DOX-BCHA complex.

Synergy of Chemo- and Photodynamic Therapies with C60 Fullerene-Doxorubicin Nanocomplex

A nanosized drug complex was explored to improve the efficiency of cancer chemotherapy, complementing it with nanodelivery and photodynamic therapy. For this, nanomolar amounts of a non-covalent nanocomplex of Doxorubicin (Dox) with carbon nanoparticle C₆₀ fullerene (C₆₀) were applied in 1:1 and 2:1 molar ratio, exploiting C₆₀ both as a drug-carrier and as a photosensitizer. The fluorescence microscopy analysis of human leukemic CCRF-CEM cells, in vitro cancer model, treated with nanocomplexes showed Dox’s nuclear and C₆₀’s extranuclear localization. It gave an opportunity to realize a double hit strategy against cancer cells based on Dox’s antiproliferative activity and C₆₀’s photoinduced pro-oxidant activity. When cells were treated with 2:1 C₆₀-Dox and irradiated at 405 nm the high cytotoxicity of photo-irradiated C₆₀-Dox enabled a nanomolar concentration of Dox and C₆₀ to efficiently kill cancer cells in vitro. The high pro-oxidant and pro-apoptotic efficiency decreased IC₅₀ 16, 9 and 7 × 10³-fold, if compared with the action of Dox, non-irradiated nanocomplex, and C₆₀’s photodynamic effect, correspondingly. Hereafter, a strong synergy of therapy arising from the combination of C₆₀-mediated Dox delivery and C₆₀ photoexcitation was revealed. Our data indicate that a combination of chemo- and photodynamic therapies with C₆₀-Dox nanoformulation provides a promising synergetic approach for cancer treatment.

The Impact of Surface Functionalization on the Biophysical Properties of Silver Nanoparticles

Among metal-based nanoparticles, silver nanoparticles (AgNPs) are particularly appealing because of their stability, functionality, and documented antimicrobial properties. AgNPs also offer the possibility of different surface modifications. In this work, we functionalized AgNPs with thiobarbituric acid or 11-mercaptoundecanoic acid residues to improve the nanoparticles’ biological activities. Subsequently, we assessed the physicochemical properties of newly synthesized AgNPs using a wide range of biophysical methodologies, including UV/vis and fluorescence spectroscopy, atomic force and scanning electron microscopy, and dynamic light scattering and isothermal titration calorimetry. Next, we examined the effect of nanoparticles functionalization on AgNPs mutagenicity and toxicity. Our study revealed that AgNPs’ surface modification affects nanoparticles aggregation, and also impacts nanoparticles’ interaction with model acridine mutagen ICR-191. AgNPs coated with MUA showed the most interesting interactions with tested ICR-191, slightly modulating its toxicity properties by decreasing the viability in treated cells.

Hierarchical Hybrid Nanostructures Constructed by Fullerene and Molecular Tweezer

For the construction of well-defined hierarchical superstructures of pristine [60]fullerene (C₆₀) arrays, pyrene-based molecular tweezers (PT) were used as host molecules for catching and arranging C₆₀ guest molecules. The formation of host-guest complexes was systematically studied in solution as well as in the solid state. Two-dimensional proton nuclear magnetic resonance spectroscopic studies revealed that PT-host and C₆₀-guest complexes were closely related to the molecular self-assembly of PT. Ultraviolet and fluorescence spectroscopic titrations indicated the formation of stable 1:1 and 2:1 (PT/C₆₀) complexes. From the nonlinear curve-fitting analysis, equilibrium constants for the 1:1 (log K₁) and 2:1 (log K₂) complexes were estimated to be 4.96 and 5.01, respectively. X-ray diffraction results combined with transmission electron microscopy observations clearly exhibited the construction of well-defined layered superstructures of the PT-host and C₆₀-guest complexes. From electron mobility measurements, it was demonstrated that the well-defined hierarchical hybrid nanostructure incorporating a C₆₀ array exhibited a high electron mobility of 1.7 × 10^-2 cm² V^-1 s^-1. This study can provide a guideline for the hierarchical hybrid nanostructures of host-guest complex and its applications.

The theory of interceptor-protector action of DNA binding drugs

The review discusses the theory of interceptor-protector action (the IPA theory) as the new self-consistent biophysical theory establishing a quantitative interrelation between parameters measured in independent physico-chemical experiment and in vitro biological experiment for the class of DNA binding drugs. The elements of the theory provide complete algorithm of analysis, which may potentially be applied to any system of DNA targeting aromatic drugs. Such analytical schemes, apart from extension of current scientific knowledge, are important in the context of rational drug design for managing drug's response by changing the physico-chemical parameters of molecular complexation.

Interactions of newly synthesized platinum nanoparticles with ICR-191 and their potential application

One of the greatest challenges of modern medicine is to find cheaper and easier ways to produce transporters for biologically active substances, which will provide selective and efficient drug delivery to the target cells, while causing low toxicity towards healthy cells. Currently, metal-based nanoparticles are considered a successful and viable solution to this problem. In this work, we propose the use of novel synthesis method of platinum nanoparticles (PtNPs) connected with their precise biophysical characterization and assessment of their potential toxicity. To work as an efficient nanodelivery platform, nanoparticles should interact with the desired active compounds spontaneously and non-covalently. We investigated possible direct interactions of PtNPs with ICR-191, a model acridine mutagen with well-established biophysical properties and mutagenic activity, by Dynamic Light Scattering, fluorescence spectroscopy, and Isothermal Titration Calorimetry. Moreover, to determine the biological activity of ICR-191-PtNPs aggregates, we employed Ames mutagenicity test, eukaryotic cell line analysis and toxicity test against the model organism Caenorhabditis elegans. PtNPs' interesting physicochemical properties associated to the lack of toxicity in a tested range of concentrations, as well as their ability to modulate ICR-191 biological activity, suggest that these particles successfully work as potential delivery platforms for different biologically active substances.

Complexation with C60 Fullerene Increases Doxorubicin Efficiency against Leukemic Cells In Vitro

Conventional anticancer chemotherapy is limited because of severe side effects as well as a quickly evolving multidrug resistance of the tumor cells. To address this problem, we have explored a C₆₀ fullerene-based nanosized system as a carrier for anticancer drugs for an optimized drug delivery to leukemic cells.Here, we studied the physicochemical properties and anticancer activity of C₆₀ fullerene noncovalent complexes with the commonly used anticancer drug doxorubicin. C₆₀-Doxorubicin complexes in a ratio 1:1 and 2:1 were characterized with UV/Vis spectrometry, dynamic light scattering, and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The obtained analytical data indicated that the 140-nm complexes were stable and could be used for biological applications. In leukemic cell lines (CCRF-CEM, Jurkat, THP1 and Molt-16), the nanocomplexes revealed ≤ 3.5 higher cytotoxic potential in comparison with the free drug in a range of nanomolar concentrations. Also, the intracellular drug's level evidenced C₆₀ fullerene considerable nanocarrier function.The results of this study indicated that C₆₀ fullerene-based delivery nanocomplexes had a potential value for optimization of doxorubicin efficiency against leukemic cells.

Stable and Biocompatible Monodispersion of C60 in Water by Peptides

The lack of solubility in water and the formation of aggregates hamper many opportunities for technological exploitation of C₆₀. Here, different peptides were designed and synthesized with the aim of monomolecular dispersion of C₆₀ in water. Phenylalanines were used as recognizing moieties, able to interact with C₆₀ through π-π stacking, while a varying number of glycines were used as spacers, to connect the two terminal phenylalanines. The best performance in the dispersion of C₆₀ was obtained with the FGGGF peptidic nanotweezer at a pH of 12. A full characterization of this adduct was carried out. The peptides disperse C₆₀ in water with high efficiency, and the solutions are stable for months both in pure water and in physiological environments. NMR measurements demonstrated the ability of the peptides to interact with C₆₀. AFM measurements showed that C₆₀ is monodispersed. Electrospray ionization mass spectrometry determined a stoichiometry of C₆₀@(FGGGF)₄. Molecular dynamics simulations showed that the peptides assemble around the C₆₀ cage, like a candy in its paper wrapper, creating a supramolecular host able to accept C₆₀ in the cavity. The peptide-wrapped C₆₀ is fully biocompatible and the C₆₀ "dark toxicity" is eliminated. C₆₀@(FGGGF)₄ shows visible light-induced reactive oxygen species (ROS) generation at physiological saline concentrations and reduction of the HeLa cell viability in response to visible light irradiation.

C60 fullerene and its nanocomplexes with anticancer drugs modulate circulating phagocyte functions and dramatically increase ROS generation in transformed monocytes

Background

C₆₀ fullerene-based nanoformulations are proposed to have a direct toxic effect on tumor cells. Previous investigations demonstrated that C₆₀ fullerene used alone or being conjugated with chemotherapeutic agents possesses a potent anticancer activity. The main aim of this study was to investigate the effect of C₆₀ fullerene and its nanocomplexes with anticancer drugs on human phagocyte metabolic profile in vitro.

Methods

Analysis of the metabolic profile of phagocytes exposed to C₆₀ fullerene in vitro revealed augmented phagocytic activity and down-regulated reactive nitrogen species generation in these cells. Additionally, cytofluorimetric analysis showed that C₆₀ fullerene can exert direct cytotoxic effect on normal and transformed phagocytes through the vigorous induction of intracellular reactive oxygen species generation.

Results

Cytotoxic action as well as the pro-oxidant effect of C₆₀ fullerene was more pronounced toward malignant phagocytes. At the same time, C₆₀ fullerenes have the ability to down-regulate the pro-oxidant effect of cisplatin on normal cells. These results indicate that C₆₀ fullerenes may influence phagocyte metabolism and have both pro-oxidant and antioxidant properties.

Conclusions

The antineoplastic effect of C₆₀ fullerene has been observed by direct toxic effect on tumor cells, as well as through the modulation of the functions of effector cells of antitumor immunity.

In vitro study of the anticancer activity of various doxorubicin-containing dispersions

Introduction: The aim of this research was to study the impact of various doxorubicin (Dox)-containing nanofluids, e.g. singlewalled carbon nanotube (SWCNT)+Dox, graphene oxide (GO)+Dox and DextranPNIPAM (copolymer)+Dox mixtures on HeLa cells (human transformed cervix epithelial cells, as a model for cancer cells) depending on their concentration. Methods: Structural analysis of GO+Dox complex was accomplished using Hartree-Fock level of theory in 6-31G** basis set in Gaussian. Dynamic light scattering (DLS), zeta-potential, scanning electron microscopy and confocal laser scanning microscopy were used. The cell viability was analyzed by the MTT assay. Results: The viability of HeLa cells was studied with the MTT assay after the incubation with various Dox-containing dispersions depending on their concentration. The size of the particles was determined by DLS. The morphology of the nanoparticles (NPs) was studied by scanning electron microscopy and their uptake into cells was visualized by confocal laser scanning microscopy. It was found that the Dextran-PNIPAM+Dox nanofluid in contrast to Dox alone showed higher toxicity towards HeLa cells up to 80% after 24 hours of incubation, whereas the SWCNT+Dox and GO+Dox nanofluids at the same concentrations protected cells from Dox. Conclusion: The importance of Dextran-PNIPAM copolymer as a universal platform for drug delivery was established, and the huge potential of Dextran-PNIPAM+Dox NPs as novel anticancer agents was noted. Based on the in vitro study of the SWCNT+Dox and GO+Dox nanofluids, it was concluded that SWCNT and GO NPs can be effective cytoprotectors against the highly toxic drugs.

A Novel Nanoconjugate of Landomycin A with C60 Fullerene for Cancer Targeted Therapy: In Vitro Studies

Introduction

Landomycins are a subgroup of angucycline antibiotics that are produced by Streptomyces bacteria and possess strong antineoplastic potential. Literature data suggest that enhancement of the therapeutic activity of this drug may be achieved by means of creating specific drug delivery systems. Here we propose to adopt C₆₀ fullerene as flexible and stable nanocarrier for landomycin delivery into tumor cells.

Methods

The methods of molecular modelling, dynamic light scattering and Fourier transform infrared spectroscopy were used to study the assembly of C₆₀ fullerene and the anticancer drug Landomycin A (LA) in aqueous solution. Cytotoxic activity of this nanocomplex was studied in vitro towards two cancer cell lines in comparison to human mesenchymal stem cells (hMSCs) using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) test and a live/dead assay. The morphology of the cells incubated with fullerene-drug nanoparticles and their uptake into target cells were studied by scanning electron microscopy and fluorescence light microscopy.

Results

The viability of primary cells (hMSCs, as a model for healthy cells) and cancer cell lines (human osteosarcoma cells, MG-63, and mouse mammary cells, 4T1, as models for cancer cells) was studied after incubation with water-soluble C₆₀ fullerenes, LA and the mixture C₆₀ + LA. The C₆₀ + LA nanocomplex in contrast to LA alone showed higher toxicity towards cancer cells and lower toxicity towards normal cells, whereas the water-soluble C₆₀ fullerenes at the same concentration were not toxic for the cells.

Conclusions

The obtained physico-chemical data indicate a complexation between the two compounds, leading to the formation of a C₆₀ + LA nanocomposite. It was concluded that immobilization of LA on C₆₀ fullerene enhances selectivity of action of this anticancer drug in vitro, indicating on possibility of further preclinical studies of novel C₆₀ + LA nanocomposites on animal tumor models.

Fullerene as a doxorubicin nanotransporter for targeted breast cancer therapy: Capillary electrophoresis analysis

The clinical use of doxorubicin (DOX) is limited by dose-related cardiomyopathy, which becomes more prevalent with increasing cumulative doses of the drug. Complexes of fullerene with DOX were designed and studied using biophysical methods. The ability of DOX to release from fullerene at different pHs was analyzed. It has been shown that the size of the fullerene-DOX complexes was ∼280 nm. The zeta potential for fullerene was -30 mV, for DOX -8 mV, and for fullerene-DOX conjugates -24 mV. Drug release was studied by CE with LIF detection. When fullerene-DOX conjugates were separated in a pH 7.5 buffer, 43% of all DOX signals were derived from free DOX, with the signal increasing as pH decreased. At pH 5.25, all DOX had been released and 100% of the signal was derived from free DOX. The release of DOX from complexes with fullerene at lower pH can be used in targeted antineoplastic therapy, resulting in lower toxicity for less acidic non-target tissue.

Does C60 fullerene act as a transporter of small aromatic molecules?

C₆₀ fullerene is reported to directly interact with biomolecules, such as aromatic mutagens or anticancer drugs. Therefore, it is extensively studied for its potential application in the fields of drug delivery and chemoprevention. Understanding the nature of fullerene-drugs interactions might contribute to optimization and modification of the existing chemotherapy systems. Possible interactions between ICR-191, a model acridine mutagen, with well-established biophysical properties and mutagenic activity, and C₆₀ fullerene aqueous solution were investigated by broad range of biophysical methods, such as Dynamic Light Scattering, Isothermal Titration Calorimetry, and Atomic Force Microscopy. Additionally, to determine biological activity of ICR-191-C₆₀ fullerene mixtures, Ames mutagenicity test was employed. It was demonstrated that C₆₀ fullerene interacts non-covalently with ICR-191 and has strong affinity to bacterial membranes. The obtained results provide practical insight into C₆₀ fullerene interactions with aromatic compounds.

Noncovalent interaction assisted fullerene for the transportation of some brain anticancer drugs: A theoretical study

The treatment of brain cancer like glioblastoma multiforme often uses chemotherapeutic drugs like temozolomide, procarbazine, carmustine, and lomustine. Fullerene loaded with these drugs help to cross the blood brain barriers. The adsorptions of the four drug molecules on the surface of the fullerene are studied mostly by using density functional theory (DFT) based method at the M06-2X/6-31G(d) level of calculations. In all four cases, the estimated interactions are noncovalent type and the average adsorption energy lies in between -5 and -11kcal/mol in the gas phase. In the aqueous and protein environment such interactions are weakened further. The binding affinity is further assessed by performing MP2 based calculations to provide interaction energies with a reasonable accuracy. Stabilities and reactivities of the drug adsorbed fullerene complexes are determined from chemical reactivity descriptors. The attached drug molecules increase the polarity of the pristine C₆₀ thus facilitating the drug delivery within the biological systems. The semiconducting behavior of C₆₀ is retained in the C₆₀-drug composite systems. The computed DOS, IR, UV spectra, and molecular orbitals in the vicinity of Fermi level are analyzed to reveal the nature of the noncovalent interactions between C₆₀ and drug molecules. The Wiberg bond order values are used to estimate the strength of the adsorption of the drug molecule on C₆₀. In all four C₆₀-drug interactions, the chemical characteristics of the drug molecule are least perturbed by the C₆₀ moiety thereby suggesting it to be a good carrier for the delivery of these brain anticancer drug molecules to the target cells.

Determination of the equilibrium constant of C60 fullerene binding with drug molecules

C₆₀-Fullerene/drug association is described by an up-scaled model that allows the microscopic equilibrium association constant to be correctly determined.

A nanocomplex of C60 fullerene with cisplatin: design, characterization and toxicity

The self-organization of C₆₀ fullerene and cisplatin in aqueous solution was investigated using the computer simulation, dynamic light scattering and atomic force microscopy techniques. The results evidence the complexation between the two compounds. The genotoxicity of С₆₀ fullerene, Cis and their complex was evaluated in vitro with the comet assay using human resting lymphocytes and lymphocytes after blast transformation. The cytotoxicity of the mentioned compounds was estimated by Annexin V/PI double staining followed by flow cytometry. The results clearly demonstrate that water-soluble C₆₀ fullerene nanoparticles (0.1 mg/mL) do not induce DNA strand breaks in normal and transformed cells. C₆₀ fullerene in the mixture with Cis does not influence genotoxic Cis activity in vitro, affects the cell-death mode in treated resting human lymphocytes and reduces the fraction of necrotic cells.

Structural self-organization of C60 and cisplatin in physiological solution

The specific features of structural self-organization of C60 fullerene and antitumor drug cisplatin (Cis) in physiological solution (0.9% NaCl) have been investigated by means of small-angle neutron scattering, scanning electron and atomic force microscopies, as well as isothermal titration calorimetry, dynamic light scattering and UV-Vis spectroscopy. The formation of C60 + Cis complexes, has been reported, unveiling the mechanism of medico-biological synergy observed during administration of the mixture of these drugs.

When a nanoparticle meets a superhalogen: a case study with C60 fullerene

The ability of a selected nanoparticle to form stable systems with superhalogens (i.e. AlF4, AlCl4, MgF3, MgCl3, LiF2, LiCl2, and LiI2) is examined on the basis of theoretical considerations supported by ab initio calculations. It is demonstrated that the C60 fullerene molecule should form stable and strongly bound (C60)˙(+)(superhalogen)(-) radical cation salts when combined with an appropriately chosen superhalogen radical (acting as an oxidizing agent). The conclusion is supported by providing: (i) the structural deformation of superhalogens and C60 nanoparticles upon ionization, (ii) predicted charge flow between the fullerene and each superhalogen (which allows estimating the amount of electron density withdrawn from the C60 molecule during the ionization process), (iii) the localization of the spin density distribution, and (iv) the interaction energies for the compounds obtained both at the B3LYP/6-31+G(d) level and at the B3LYP-D3/6-31+G(d) level. Solvent effects have been considered in the present study by means of the polarizable continuum model. It is found that the stability of C60/superhalogen species can be improved in solvents. We believe that the results provided in this contribution may likely be of prospective relevance in the future studies on the issue of binding and removal of this potentially risky nanoparticle.

Study of the complexation between Landomycin A and C60 fullerene in aqueous solution

We report here the first investigation of the non-covalent complexation between C₆₀ fullerene and angucycline antibiotic Landomycin A.

Complex of C60 Fullerene with Doxorubicin as a Promising Agent in Antitumor Therapy

The main aim of this work was to evaluate the effect of doxorubicin in complex with C60 fullerene (C60 + Dox) on the growth and metastasis of Lewis lung carcinoma in mice and to perform a primary screening of the potential mechanisms of C60 + Dox complex action. We found that volume of tumor from mice treated with the C60 + Dox complex was 1.4 times less than that in control untreated animals. The number of metastatic foci in lungs of animals treated with C60 + Dox complex was two times less than that in control untreated animals. Western blot analysis of tumor lysates revealed a significant decrease in the level of heat-shock protein 70 in animals treated with C60 + Dox complex. Moreover, the treatment of tumor-bearing mice was accompanied by the increase of cytotoxic activity of immune cells. Thus, the potential mechanisms of antitumor effect of C60 + Dox complex include both its direct action on tumor cells by inducing cell death and increasing of stress sensitivity and an immunomodulating effect. The obtained results provide a scientific basis for further application of C60 + Dox nanocomplexes as treatment agents in cancer chemotherapy.

Interaction of C60 fullerene complexed to doxorubicin with model bilipid membranes and its uptake by HeLa cells

With an aim to elucidate the effects of C60 fullerene complexed with antibiotic doxorubicin (Dox) on model bilipid membranes (BLM), the investigation of the electrical properties of BLM under the action of Dox and C60 fullerene, and of their complex, C60+Dox,was performed. The complex as well as its components exert a clearly detectable influence on BLM, which is concentration-dependent and also depends on phospholipid composition. The mechanism of this effect originates either from intermolecular interaction of the drug with fatty-acid residues of phospholipids, or from membranotropic effects of the drug-induced lipid peroxidation, or from the sum of these two effects. By fluorescence microscopy the entering of C60 + Dox complex into HeLa cells was directly shown.

C60 fullerene affects elastic properties and osmoregulation reactions of human lymphocytes

The influence of aqueous solution of pristine C60 fullerene (C60FAS) on functional activity of lymphocytes from a healthy person was studied for the first time. By means of atomic force microscopy, it was found that C60FAS in a concentration of 0.1 mg/ml increases the stiffness of the lymphocyte membrane by 41% (p < 0.05) and lowers the functional activity of the plasmalemma surface, thereby constraining the use of its membrane material in physiological reactions using a hypotonic model in vitro. However, a cell retains the ability to regulate its volume and demonstrates relative resistance to hypo-osmotic stress. The resistance of lymphocytes in hypo-osmotic medium is facilitated by activation of the nucleus by C60 fullerene particles, which regulates the implementation of two consistent phases of an increase and decrease of cell volume, thereby retaining cell viability. All these indicate the impact of C60 fullerene on the cellular nucleus.