ABSTRACT
Covalent attachment of the enzymes glucose oxidase and catalase to carbon nanotubes enables the tandem catalytic conversion of glucose and H(2)O(2) formed to power autonomous movement of the nanotubes.
Subject(s)
Catalase/chemistry , Glucose Oxidase/chemistry , Motion , Nanotubes, Carbon/chemistry , Catalysis , Enzymes, Immobilized/chemistry , Glucose/chemistry , Hydrogen Peroxide/chemistry , Oxygen/chemistry , Particle Size , Surface Properties , Water/chemistryABSTRACT
Carbon nanotubes (CNT) are intensively being developed for biomedical applications including drug and gene delivery. Although all possible clinical applications will require compatibility of CNT with the biological milieu, their in vivo capabilities and limitations have not yet been explored. In this work, water-soluble, single-walled CNT (SWNT) have been functionalized with the chelating molecule diethylentriaminepentaacetic (DTPA) and labeled with indium ((111)In) for imaging purposes. Intravenous (i.v.) administration of these functionalized SWNT (f-SWNT) followed by radioactivity tracing using gamma scintigraphy indicated that f-SWNT are not retained in any of the reticuloendothelial system organs (liver or spleen) and are rapidly cleared from systemic blood circulation through the renal excretion route. The observed rapid blood clearance and half-life (3 h) of f-SWNT has major implications for all potential clinical uses of CNT. Moreover, urine excretion studies using both f-SWNT and functionalized multiwalled CNT followed by electron microscopy analysis of urine samples revealed that both types of nanotubes were excreted as intact nanotubes. This work describes the pharmacokinetic parameters of i.v. administered functionalized CNT relevant for various therapeutic and diagnostic applications.
Subject(s)
Nanotubes, Carbon/analysis , Animals , Female , Half-Life , Indium Radioisotopes , Injections, Intravenous , Mice , Mice, Inbred BALB C , Microscopy, Electron, Transmission , Molecular Structure , Pentetic Acid , Tissue DistributionABSTRACT
We demonstrate the possibility of using carbon nanotubes (CNTs) as potential devices able to improve neural signal transfer while supporting dendrite elongation and cell adhesion. The results strongly suggest that the growth of neuronal circuits on a CNT grid is accompanied by a significant increase in network activity. The increase in the efficacy of neural signal transmission may be related to the specific properties of CNT materials, such as the high electrical conductivity.
Subject(s)
Electrochemistry/methods , Nanotechnology/methods , Nanotubes, Carbon/chemistry , Neurons/metabolism , Animals , Astrocytes/metabolism , Cell Adhesion , Cell Survival , Crystallization , Dendrites/metabolism , Electronics , Glial Fibrillary Acidic Protein/metabolism , Hippocampus/metabolism , Humans , Immunohistochemistry , Models, Chemical , Signal Transduction , Time FactorsABSTRACT
Carbon nanotubes (CNTs) constitute a class of nanomaterials that possess characteristics suitable for a variety of possible applications. Their compatibility with aqueous environments has been made possible by the chemical functionalization of their surface, allowing for exploration of their interactions with biological components including mammalian cells. Functionalized CNTs (f-CNTs) are being intensively explored in advanced biotechnological applications ranging from molecular biosensors to cellular growth substrates. We have been exploring the potential of f-CNTs as delivery vehicles of biologically active molecules in view of possible biomedical applications, including vaccination and gene delivery. Recently we reported the capability of ammonium-functionalized single-walled CNTs to penetrate human and murine cells and facilitate the delivery of plasmid DNA leading to expression of marker genes. To optimize f-CNTs as gene delivery vehicles, it is essential to characterize their interactions with DNA. In the present report, we study the interactions of three types of f-CNTs, ammonium-functionalized single-walled and multiwalled carbon nanotubes (SWNT-NH3+; MWNT-NH3+), and lysine-functionalized single-walled carbon nanotubes (SWNT-Lys-NH3+), with plasmid DNA. Nanotube-DNA complexes were analyzed by scanning electron microscopy, surface plasmon resonance, PicoGreen dye exclusion, and agarose gel shift assay. The results indicate that all three types of cationic carbon nanotubes are able to condense DNA to varying degrees, indicating that both nanotube surface area and charge density are critical parameters that determine the interaction and electrostatic complex formation between f-CNTs with DNA. All three different f-CNT types in this study exhibited upregulation of marker gene expression over naked DNA using a mammalian (human) cell line. Differences in the levels of gene expression were correlated with the structural and biophysical data obtained for the f-CNT:DNA complexes to suggest that large surface area leading to very efficient DNA condensation is not necessary for effective gene transfer. However, it will require further investigation to determine whether the degree of binding and tight association between DNA and nanotubes is a desirable trait to increase gene expression efficiency in vitro or in vivo. This study constitutes the first thorough investigation into the physicochemical interactions between cationic functionalized carbon nanotubes and DNA toward construction of carbon nanotube-based gene transfer vector systems.
Subject(s)
DNA/chemistry , Gene Transfer Techniques , Genetic Vectors/chemistry , Nanotubes, Carbon/chemistry , Plasmids/chemistry , Cations , DNA/administration & dosage , DNA/genetics , Genetic Vectors/genetics , Lysine/analogs & derivatives , Microscopy, Electron, Scanning , Plasmids/genetics , Quaternary Ammonium Compounds/chemistry , Surface Plasmon ResonanceABSTRACT
Functionalized cationic carbon nanotubes are able to form a stable complex with CpG ODN based on charge interaction and to increase the immunostimulatory activity of CpG motifs.
Subject(s)
Adjuvants, Immunologic/administration & dosage , Adjuvants, Immunologic/chemistry , CpG Islands/immunology , Interferon-gamma/metabolism , Nanotubes, Carbon/chemistry , Oligonucleotides/chemistry , Oligonucleotides/immunology , Animals , Cations , Interleukin-6/metabolism , Kinetics , Lymphocytes/drug effects , Lymphocytes/immunology , Mice , Oligonucleotides/administration & dosage , Surface Plasmon ResonanceABSTRACT
Organofullerene derivatives have shown a great potential in a wide variety of biological activities such as DNA photocleavage, HIV-protease inhibition, neuroprotection and apoptosis. Among the plethora of functionalized organofullerenes that have been synthesized, fullerene-based amino acids are particularly appealing for structural studies and biological applications. When the fullerene-framework is incorporated into peptides, its original properties can be substantially modified. In addition, the water-solubility of the fullerene derivatives is enhanced, which makes such molecules amenable to biological studies. In this review, recent advances in the growing field of medicinal chemistry of fullerene derivatives will be discussed. Emphasis will be given to the synthesis of the biggest unnatural amino acid 3,4-fulleroproline (Fpr) and its derivatives. For example, Fpr derivatives have been found to interact with different hydrolytic enzymes and selectively discriminate between rationally designed peptides. Fullerene-based peptides have been found to substantially activate enzymes involved in the oxidative deamination of biogenic amines. In addition, their membranotropic properties and effects on the structure and permeability of the lipid bilayer of phosphatidylcholine liposomes as well as the transmembrane transport of bivalent metal ions have been studied. Finally, applications in medicinal chemistry of such types of amino acids and peptides will be highlighted.
Subject(s)
Amino Acids , Fullerenes , Peptides , Amino Acids/chemical synthesis , Amino Acids/chemistry , Amino Acids/pharmacology , Animals , Fullerenes/chemistry , Fullerenes/pharmacology , Humans , Molecular Structure , Peptides/chemical synthesis , Peptides/chemistry , Peptides/pharmacology , SolubilitySubject(s)
DNA/administration & dosage , Drug Delivery Systems , Genetic Therapy/methods , Plasmids/administration & dosage , Animals , CHO Cells , Carbon , Cell Membrane/metabolism , Cricetinae , DNA/chemistry , Ethylene Glycols/chemistry , HeLa Cells , Humans , Indicators and Reagents , Microscopy, Electron, Transmission , Particle Size , Pyrrolidines/chemistry , Quaternary Ammonium Compounds/chemistryABSTRACT
Functionalised carbon nanotubes are able to cross the cell membrane and to accumulate in the cytoplasm or reach the nucleus without being toxic for the cell up to 10 [micro sign]M.
Subject(s)
Cell Membrane/metabolism , Nanotubes, Carbon , Peptides/metabolism , 3T3 Cells , Animals , Flow Cytometry , Mice , Microscopy, Confocal , Microscopy, Fluorescence , Nanotubes, Carbon/toxicity , Particle Size , Protein TransportABSTRACT
A peptide analogue from a histone H3 protein containing the L-fulleropyrrolidino-glutamic acid has been prepared by a solid-phase approach and has been fully characterized. By molecular modelling it was verified that this peptide derivative is able to retain a binding capacity to the MHC (major histocompatibility complex) molecule similar to that of the cognate epitope.
Subject(s)
Fullerenes/chemistry , Histones/chemistry , Peptides/chemistry , Peptides/chemical synthesis , Chromatography, High Pressure Liquid , Epitopes/chemistry , Epitopes/immunology , Glutamic Acid/chemistry , Models, Molecular , Molecular Structure , Peptides/immunology , Protein Structure, TertiarySubject(s)
Antibodies, Viral/immunology , Drug Delivery Systems , Nanotubes, Carbon/chemistry , Peptides/chemistry , Vaccines/administration & dosage , Animals , Antibodies, Monoclonal/immunology , Antigen-Antibody Reactions , Epitopes/immunology , Foot-and-Mouth Disease Virus/chemistry , Foot-and-Mouth Disease Virus/immunology , Immunization , Mice , Neutralization Tests , Peptides/administration & dosage , Peptides/immunology , Vaccines/immunologyABSTRACT
Carbon nanotubes (NTs) are becoming highly attractive molecules for applications in medicinal chemistry. The main problem of insolubility in aqueous media has been solved by developing a synthetic protocol that allows highly water-soluble carbon NTs to be obtained. As a result, biologically active peptides can be easily linked through a stable covalent bond to carbon NTs. We have demonstrated that a bound peptide from the foot-and-mouth disease virus, corresponding to the 141-159 region of the viral envelope protein VP1, retained the structural integrity and was recognized by monoclonal and polyclonal antibodies. In addition, this peptide-NT conjugate is immunogenic, eliciting antibody responses of the right specificity. Such a system could be greatly advantageous for diagnostic purposes and could find future applications in vaccine delivery.
Subject(s)
Capsid Proteins/chemistry , Capsid Proteins/immunology , Nanotubes, Carbon/chemistry , Nanotubes, Carbon/immunology , Peptide Fragments/chemistry , Peptide Fragments/immunology , Chromatography, High Pressure Liquid , Epitopes, B-Lymphocyte/chemistry , Epitopes, B-Lymphocyte/immunology , Foot-and-Mouth Disease Virus/immunology , Nanotechnology/methods , Nuclear Magnetic Resonance, BiomolecularABSTRACT
The solid-phase synthesis of peptides (SPPS) containing [60]fullerene-functionalized amino acids is reported. A new amino acid, fulleropyrrolidino-glutamic acid (Fgu), is used for the SPPS of a series of analogues of different length based on the natural Leu(5)-Enkephalin and on cationic antimicrobial peptides. These fullero-peptides were prepared on different solid supports to analyze the influence of the resin on the synthesis. Optimized protocols for the coupling and deprotection procedures were determined allowing the synthesis of highly pure peptides in sufficient quantities for evaluation of biological activities. In particular, to avoid side reactions of the fullerene moiety with bases and nucleophiles, the removal of the protecting groups was performed under inert conditions (nitrogen or argon in the dark). We have encountered serious problems with the recovery of the crude compounds, especially when Fgu was inserted in the proximity of the resin core as fullero-peptides tend to remain embedded inside the resin. Eventually, all of the fullero-peptides were easily purified, and the cationic peptides were tested for their antimicrobial activities. They displayed a specific activity against the Gram-positive bacterium S. aureus and also lysed erythrocytes. The availability of a fullero-amino acid easily useable in the SPPS of fullero-peptides may thus open the way to the synthesis of new types of biologically active oligomers.
Subject(s)
Fullerenes/chemistry , Oligopeptides/chemical synthesis , Amino Acids/chemistry , Anti-Bacterial Agents , Anti-Infective Agents/chemical synthesis , Anti-Infective Agents/pharmacology , Candida albicans/drug effects , Enkephalin, Leucine/analogs & derivatives , Enkephalin, Leucine/chemical synthesis , Escherichia coli/drug effects , Fluorenes/chemistry , Fullerenes/pharmacology , Microbial Sensitivity Tests , Oligopeptides/pharmacology , Spectrometry, Mass, Electrospray Ionization , Staphylococcus aureus/drug effectsABSTRACT
High solubility of SWNTs and MWNTs in water is obtained by organic functionalisation; derivatisation with N-protected glycine is also easily achieved.