Fullerene Uses and Applications – The Comprehensive Overview
Despite their unusual name and their relatively short time on the research scene, there are many possible fullerene uses. These so called carbon allotropes (as well as graphite, graphene and diamond known to date) consist of carbon molecules in the form of various shapes as hollow sphere, tube or ellipsoid. This fact made them very interesting for science and industries, as the other known allotropes have many various commercial uses. Based on the molecular shape, these molecules could be divided into spherical (also called buckminsterfullerenes or buckyballs) and cylindrical (termed as nanotubes or buckytubes). Due to their features, buckyballs and buckytubes have been intensively examined especially for their possible technical applications in nanotechnology, material science and electronics but also in pharmaceutical and cosmetic industry and last but not least in medicine.
Fullerene uses could be infinite
The most abundant and the first studied representative of these novel family of molecules is buckminsterfullerene (C60) which was discovered in 1985 by Richard Smalley, Robert Curl, James Heath, Sean O’Brian and Harold Kroto at Rise University.
It was named after Richard Buckminster Fuller, an architect known for popularization of geodesic dome with similar shape as C60.
Scientists who discovered C60 were awarded by Nobel Prize in 1996.
This led to extensive interest of many research groups all over the world and subsequently to the discovery of a large number of structural variants derived from basic molecule such as megatubes, fullerene rings or polymers.
After that, the shorter name “fullerene” started to be commonly used for the whole family of these carbon allotropes. The suffix “-ene” refers to the fact, that each carbon atom is bonded to three others by covalent binding.
The main properties that made fullerenes so interesting for many different research groups but also for nanomaterial companies include:
- Simple structure – contain 60 atoms of carbon and has soccer-ball shape
- Hollowness – suggesting their potential uses as they can be filled
- Uniformity – contain only one molecule typ
These novel molecules have high potential to be better in many aspects compared to carbon allotropes known so far. Based on their unique and uniform structure, they are predicted to be synthesized by cheaper method and even have more possible commercial uses than other carbon compounds which are world-widely used in many different fields including medicine, nanotechnology or industry.
The common process of fullerene production
- Fullerene or fullerene-containing soot synthesis which is mediated by sending a large current between two graphite electrodes. It has to be done in an inert atmosphere. The carbon plasma arc between electrodes subsequently cools and gives rise to sooty residues from which, C60 could be isolated in following steps.
- Synthesis of derivatives
- Post-processing (for example dispersion into a matrix)
The diversity in buckyballs possible usage
Due to their many described properties, fullerenes and their derivatives seem to have an infinite number of uses across various disciplines including the following ones:
- Few years ago utilization of C60 in armor was discussed in science community
- They were also studied for their potential to be very nice tool in medicine for (among others) targeting resistant bacteria by antibiotics conjugated with carbon molecule or for targeting cancer cells with special benefits for patients undergoing cancer treatment which is described in more detail bellow
- In 2005, buckyballs utilization as light-activated antimicrobial agents was published
- Properties such as superconductivity and heat resistance are extensively studied to be used in nanomaterial development
What is buckminsterfullerene used for in commercial technologies?
As mentioned above, buckminsterfullerene or C60 was the first discovered fullerene molecule which gave name to whole new family. It is also the longest examined and the best described member and is predicted to have the most possible usage.
Basic properties of C60
- Smallest fullerene molecule
- Contains pentagonal/hexagonal rings
- High molecular symmetry
- Common in nature, present in soot
- Structure of truncated icosahedrons resembling an association football ball
- Exceptionally stable
- Resistant to radioactivity
- Resistant to chemical corrosion
- Accepts electrons and easily released them
Nowadays, buckminsterfullerenes are used as so called dry lubricants in coating applications. Nanosphere powders present composite coatings which are made from inorganic
fullerene-like material (IFLM). This material was developed to suppress friction and enhanced wear resistance in parts that are exposed to sliding or rolling contacts. After IFLM incorporation into a matrix, the particles enable independent control of friction and wear. IFLM strategy finds application for example in:
- Ball bearings
- Artificial joints
Main classes of IFLM-based coatings
- Metal matrix coatings
- Materials such as cobalt and nickel are used in their production by IFLM powder suspending in a plating bath solution
- Useful in high load applications that require hard coatings
- Based on aqueous coating techniques
- Polymer matrix coatings
- Softer matrix suitable for intermediate load-bearings applications
- Examples: Polyketone, Nylon, Polypropylene
- Matrix-less fullerene films
- Contain 85% of C60 and 15% of its derivative C70
- Thickness of 10nm
- Plated on metallic substrate coated by 1nm Ge sublayer before
- Amorphous (revealed by transmission electron microscopy)
- No variations in surface potential
The fullerene-coated surfaces have a high potential to be used in microbial fuel cell applications due to their ability to promote the formation of biofilm produced by studied organism if conducting basic surface is used.
What are fullerenes used for – a chemical point of view
Medical applications are usually highlighted because of the benefits which they can bring to financial sphere and their potential to improve the population life quality but on the other hand there are other useful applications of C60, that can improve living standard in a broad sense.
Because fullerenes and their derivates were discovered to have high electron affinity and they are able to transfer electrons, they can act as acceptors in solar cells system which is based on electron transport from light excited material (donor) to electrode. Whole process is mediated by the acceptor molecule. The example of commonly used acceptor is Phenyl-C61-butyryc acid methyl ester (PCMB) which is used with polythionphene (P3HT) as donor.
Hydrogen gas storage
Fullerenes are able to hydrogenate and dehydrogenate easily due to their one-of-a-kind molecule structure (consist of carbon atoms only). During hydrogenation, C=C double bonds which are present between carbon rings in C60 molecule are easily broken which gives rise to C-C single bonds and C-H bonds. The strength of C-H bonds is lower in comparison with C-C which enables relatively ease hydrogen release after exposure to heat. Up to 36 atoms of hydrogen can be hold by one C60 molecule.
Uses of C60 fullerenes in a pharmaceutical point of view
Since their discovery in 1985, fullerenes were extensively examined for possible biomedical applications. Investigations of their physical, biological and chemical properties have yielded important and promising information. The greatest problem in the medical field is that fullerenes are insoluble in aqueous medium and they posses high tendency to form aggregates. Scientists have tried to overcome these issues by using three main techniques as followed:
- Encapsulation in special carriers
- Suspension with the help of co-solvents
- Chemical functionalizatio
All known classes of chemicals have been used for the creation of derivatives that confirmed their high chemical activity and wide versatility of chemical reactions. They could be used for production of novel materials with possible use in medical field. To date, fullerenes and their derivatives are used in few medical applications including for example antiviral activity or drug and gene delivery. These and several more are discussed in more detail in the following text.
Based on the chemical properties like very high electron affinity and the large number of conjugated double bonds, fullerenes are known to act as excellent antioxidants. They are called „radical sponge” due to their ability to interact with a number of free radicals before being consumed. The major advantage of using them as an antioxidant is that they seem to be really safe and biocompatible that they can act within the cell.
2) Antiviral agents
Different modes of pharmaceutical actions have been described for compounds with antiviral activity which made them to be the center of medical interest. Fullerenes and their derivatives are believed to act as these compounds also termed as antiviral agents. One of their most exciting properties is the capability to suppress the human deficiency virus (HIV) replication which led to inhibition of acquired immunodeficiency syndrome (AIDS) manifestation. In more detail, it was observed that fullerene derivatives are able to inhibit HIV protease which in turn prevents HIV 1 replication and the subsequent development of the disorder.
Fullerenes posses a great potential for research and development of novel anti-HIV drugs.
The antiviral activity is strongly influenced by the relative position of side chains on C60. This was claimed by synthesis and subsequent characteristics of series fullerene derivatives which were found to really have antiviral activity, examples are listed below.
- Fulleropyrrolidines (contain 2 ammonium groups) were described as HIV-1 and HIV-2 antagonists
- Cationic, anionic and amino acids derivatives were seen to inhibit hepatitis C virus replication
- Amino acid derivatives of C60 were found to be able to inhibit human cytomegalovirus replication
- Water insoluble derivatives shown antiviral activity against enveloped viruses
3) Gene and drug delivery
The delivery of drugs means the transport of a chemical compound into the site, where it is supposed to have the right effect. For this purpose, it is crucial to use very safe but still effective molecules. Fullerenes seem to be nice carriers because they showed good biocompatibility, selectivity and they are still small enough for the right diffusion in organism, which is needed for their final localization
In the case of gene delivery, foreign DNA is introduced into the cells, which is supposed to bring the desired effect. For this purpose, DNA sequences are connected with amino acid derivatives of C60. In the proper site, these sequences are disconnected by loss or denaturation of these amino groups. Biochemical experiments have revealed better abilities compared to vectors which are commonly used for this application.
4) Photosensitizers in photodynamic therapy
This type of treatment could be another and maybe better option for cancer patients than classical anti-cancer therapy. In this case, C60 can be used as a non-toxic compounds which are able to target malignant cells.
Fullerenes become toxic after light exposure leading to cancer cell death.
New photosensitizers were tested using HeLa cells, their main features include:
- increased agility to be absorbed by cancer cells
- potential to still trigger cell death
- short-time stay in a body (preventive of unwanted cell death)
In 2006, highly water-soluble C60-N vinylpyrrolidine copolymer was described as a new photosensitizer. Radical polymerization enables covalent incorporation of C60 into poly (vinylpyrrolidin) chain which gave rise to most water-soluble fullerene reported so far.
In 2007, polyethyleneglycol (PEG)-conjugated fullerene containing Gd3+ ions was used for photodynamic therapy while combined with magnetic resonance imaging (MRI).
Recently, it was shown that monocationic fullerenes are highly effective in killing of cancer cells by illumination-induced apoptosis.
What are buckyballs used for in biomedicine?
Spherical fullerenes also termed buckyballs and their derivatives were found to have brought many benefits in different biomedical applications including:
- Suppression of important factors such as nitric oxide and TNF-alpha, responsible for neutrophilic lung inflammation which in turn attenuate this illnesses
- Protection of neurons against apoptosis in vitro and in vivo and prevention from brain tissue ischemia and iron-induced oxidative stress injuries
- Protection of visceral organs (heart, liver, kidney, etc.) from injuries caused by oxidative stress
- Cells protection against the ultraviolet A irradiation (they act as so called cytoprotectors and in this case they can bind to Reactive Oxygen Species (ROS) which subsequently leads to cell damage protection
- Inhibition of cellular apoptosis caused by oxidative stress
- Cellular imaging and bio-distribution detection
- Serum protein profiling
Fullerene C60 uses and applications based on its redox properties
The basal cellular respiration processed from mitochondrial oxidative phosphorylation is known to cause the endogenous production of reactive oxygen species (ROS) including hydroxyl radical or superoxid anion.
ROS are involved in cell signaling and form the necessary part of energetic metabolism in organisms. When the levels of ROS are too high or cellular antioxidant defense system does not work properly, oxidative stress occurs. This situation might lead to damage of cellular proteins, lipids and nucleic acid which are probably involved in pathogenesis of some illnesses as neurodegeneration, cancer or atherosklerosis.
The extrinsic antioxidants could help cells to reduce oxidative stress by removing ROS.
Due to its hollow spherical structure with 30 carbon-carbon (C=C) double bonds, C60 can react with at least 15 benzyl radicals or 34 methyl radicals while forming stable adducts. Moreover, it was discovered to be able to react with many superoxides without being consumed and finally, C60 was considered to act as most efficient “free radical sponge”. However, more research groups have been worked on development of water soluble or other derivatives.
What can fullerenes be used for in orthopaedic research
Nowadays, among the other medical specializations, orthopaedic seems to be the most promising for fullerenes and their derivatives usage. They are supposed to have importance in treatment of many skeletal disorders such cartilage degeneration, osteoporosis or intervertebral disc degeneration (IVDD)
· Cartilage degeneration treatment
The loss of functional chondrocytes leads to cartilage degeneration. The treatment is based on derivation of new chondrocytes from progenitor cells but improvement of this method is still needed because not enough functional cells could be produced.
Water-soluble C60 was explored to have positive effect on promotion of primary embryonic limb bud cells chondrogenesis. This effect was proportional to the concentration of the compound. The mechanism by which buckminsterfullerene is able to influenced chondrogenesis remains elusive. It might be due to its anti-oxidative properties or it might concentrate other substances known to promote the whole process of chondrocytes differentiation.
Another in vitro study revealed that water-soluble fullerene derivative is able to down-regulate production of matrix-degradating enzymes in chondrocytes from patients with osteoarthritis when cultured with specific factors such as interleukin-1 beta or H2O2.
Furthermore, C60 significantly elevated the biosynthesis of chondrogenesis supporting molecules such as proteoglycans or collagen type II. The other possible use of fullerene in cartilage degeneration therapy is its injection directly into tissue. Scientists predict that it might act as so called “molecular bearing” to coat, lubricate and even protect the function of joint cartilage.
· Osteoporosis therapy
Osteoporosis is a skeletal illness with following characteristics: reduced bone mineral density, Deterioration of micro architecture of the skeleton and increased risk of fracture
The C60 derivatives have high potential to be used in osteoporosis treatment because of their strong affinity to the calcium phosphate mineral hydroxyapatite of bone. It means that C60-based vectors could bring traditional bone promotion agents to destructive bone tissue.
· IVDD therapy
IVDD is believed to cause the low back pain, one of the most common problems associated with musculoskeletal disorders. It is very likely that mitochondrial-derived ROS contribute to manifestation of IVDD. It was described that free radical scavengers are important part in process of IVDD prevention.
Experiments with C60 derivative fullerol (because of its known ability to act as a free radical scavenger) were performed and revealed that it is able to effectively reverse the matrix degradation under the specific conditions.
· Radiculopathy treatment
Spinal nerve root inflammation which is associated with back pain could be caused by IVDD. Fullerol was observed to be able to suppress inflammatory responses of dorsal root ganglia via decreasing ROS levels.
Current and future potential uses of fullerenes
Although many possible uses of this novel family of carbon allotropes are still under extensive research, some of them were successfully applied in commercial sphere. To date, there is no product based on fullerenes only but these molecules were used as substances added into existing materials, because they are able to improve material properties or bring some new advantages to existing products.
Fullerenes were used as additives in cosmetics for developing the so called UV whitening cream. In this product the addition of C60 enhanced the absorption through skin and helped protect skin against the consequences of oxidative stress such as dark spots or wrinkles.
There is a high potential for fullerenes to be used in each field, but another research is required. The main challenge is to develop product which would be better, cheaper and even more environment friendly in comparison with products which are commonly available.
The challenges in fullerene research
Though some fullerenes are known to be useful in biomedicine or pharmaceutics, they cannot be commonly used because of the relatively high price of their production in large scales.
There are also toxicity issues that have to be solved. Comprehensive studies revealed that toxicity of C60 is not only time and dose-dependent, but even depend on various other factors. This fact is very limiting for their common use in pharmacology. The toxicity has to be tested for each novel application, which is costly and time consuming.
When all challenges will be overcome, these novel carbon allotropes will probably become one of the most used carbon allotropes in the world.
The possible future of fullerenes
- microscopic ball bearings
- new cancer treatments based on buckyballs filled with radioactive atoms which ensure the integrity of isotopes after injection by carbon barrier
- neuronal protectors used for treatment of Parkinson’s and Alzheimer’s diseases
- superpower full battery made by lithium and fluorine atoms which would create energy when combined inside buckyballs
- powerful rocket fuels
- conducting polymers for substitution of metal ones
- new class of catalytic converters
- the base for new types of plastics created by stringing buckyballs together followed by adding of different atoms or chemical groups to carbons which would enable to alter the molecule in million ways
- another uses in plastics and other organic compounds with carbon backbones
- many others because they can replace most of the molecules which are used at present
Are the applications of fullerenes really so wide, interesting, unique and useful?
There is a description of relatively new carbon molecule in this article, its actual application in various branches and potential.
This molecule evince special properties that can influence industry, scientific research, give new possibilities to treating serious diseases, etc.
Maybe you will make a decision to buy C60 after having read the article and use some of its great application.
Before giving an answer, let us try to get to know themselves a little bit more.
Fullerene is an allotrope of carbon. Individual carbon atoms create hollow sphere, ellipsoid, tube or other shapes that consist of hexagons and pentagons.
Based on the molecular shape, they can be divided into next groups:
- Spherical - named buckminsterfullerenes or buckyballs (association with football)
- Cylindrical - hollow tubes of very small dimension with single or multiple walls (nanotubes or buckytubes). Predominantly used in electronic industry.
- Mega tubes - Varying in dimensions than nanotubes as larger in diameter with walls of different thickness.
- Polymers – 2D or 3D, formed under high pressure and temperature conditions
- Nano „onions – Spherical particles having multiple layers which surrounds buckyball core. They are used for example as lubricants or for energy saving.
- Linked “ball-and-chain” dimmers – Two buckyballs linked by a carbon chains
Application of fullerenes hit many industrial and scientific branches
They are used for example in these branches:
- Industry – cosmetic, energy saving, electronic, pharmaceutic
- Science – chemistry, physics, biology
Short description of allotropes
As it was said, fullerenes are allotropes of carbon. The word allotropy is created from two ancient Greek words allos (meaning other) and tropos (“manner” or “form”). Allotropy is the property of some (chemical) element to exist in two or more different forms, in the same physical state. Those substances are known as allotropes of this element.
Individual allotropes (of an element) are different modification of an element that means the atoms of the element are bonded together in a different manner.
Allotropy or allotropism (from Ancient Greek allos (meaning 'other'), and tropos (meaning 'manner, form') is the property of some chemical elements to exist in two or more different forms, in the same physical state, known as allotropes of these elements.
Very simple and generally known example can be graphite and diamond. Both are allotropes of carbon, but carbon atoms in diamond are bonded together in tetrahedral lattice arrangement, whereas atoms of graphite are in sheets of a hexagonal lattice).
Examples of the best known allotropes
Some examples of the best-known allotropes are given below with a short description.
- Carbone: for example graphite (soft), diamond(hard), fullerenes (stable can be harder than diamond)
- Oxygen: for example dioxygen (O2, colorless), ozone (O3-blue), tetra oxygen (O4-metastable), octaoxygen (red)
- Phosphorus: for example white phosphorus (crystalline solid of tetra phosphorus (P4) molecules, black phosphorus (semiconductor, analogous to graphite)
Discovery and research milestones
History of their discovery is relatively new and very interesting. The milestones are given in the next points with their short description.
- 1966 - David Edward Hugh Jones (a British chemist and author, under the pen name Daedalus). He published for 38 years in New Scientist, Nature and other from 1964 until 2002. Daedalus most noteworthy scientific idea was probably the prediction of hollow carbon molecules before buckminsterfullerene was known, and long before a Nobel Prize was awarded for the discovery. His hypothesis was not accepted.
- 1970 - Eji Osawa (June 6, 1935, from 1990 full professor at Toyahashi University of Technology, where he retired in 2001), Japanese chemist. He predicted the existence of C60 in 1970. Eji Osawa noticed that the structure of a corannulene molecule was a subset of a football shape, and he came with a hypothesis that a full ball shape could also exist. Japanese scientific journals reported his idea, but only in Japan.
- 1970 - R.W.Henson, with no prior knowledge of Daedalus nor Osawa proposed the structure and made a model of C60. However, evidence for this new form of C was very weak and was not accepted. His work was never published. The international journal Carbon mentioned his contribution in a special issue only in 1992 (Carbon, Vol 30 No 8).
- 1984 - Exxon company scientists noticed an interesting phenomenon during the evaporation of graphite with a laser and cooling in supersonic jet: bigger carbon clusters contained more molecules with even number of atoms then odd. They did not detect prevailing occurrence of clusters with 60 carbon atoms and therefore they did not come to know what substance they observed.
- 1985 - Discovery of C60, the most prominent fullerene.
Harold Kroto (at that time University of Sussex), Richard Smalley and Robert Curl (at that time Rice University in Houston) explored composition of stars atmosphere and of interstellar dust. They observed an exotic molecule during the laboratory tests. The molecule was a cluster of 60 carbon atoms. The first pure fullerit (fullerites are the solid phases of C60) was produced in Heidelberg (Max Planck Institute for Nuclear Physics).
- 1990 - W. Krätschmer (Max Planck Institute for Nuclear Physics in Heidelberg) together with his PhD student Konstantinos Fostiropoulos and with Donald Huffman (the University of Arizona) found a method that allows production of C60 in sufficient quantities.
- 1991 - Discovery of superconductivity of C60 with alkali metals in Bell Laboratories
- 1992- First preparation of AC60. These phases exhibit a polymer structure, which is air-stable.
- 1992- TDAE C60-Fullerene is supposed to be an itinerant ferromagnet.
- 1996- The Royal Swedish Academy of Sciences awards the Nobel Prize in chemistry to R. F. Curl, H. W. Kroto and R. E. Smalley for the discovery of fullerenes.
What special properties lead to application of buckminsterfullerenes
They evince special properties, for example:
- superconductivity at 35K,
- hardness higher then diamond,
- extraordinary resistance to physical Influences (temperature and pressure),
- special electric properties,
- some organic derivatives of fullerenes evince magnetic properties,
- wide non-linear optic reaction,
- possibility to insert into the hollow,
- catalytic properties,
- antioxidant properties
- antibacterial properties
If we look at the list above, we must confirm this new interesting substance must be very useful in many fields of human activities. Its special properties known up to now determine them to the group of very important items for industry, business or science. Their development and research is permanently going on, which brings new possibilities of their application and next research projects.
Actual buckyballs application with some short description
From 1985 to 1990, a series of studies indicated that C60 and C70 were indeed exceptionally stable and provided convincing evidence for the cage structure proposal. In addition, evidence was obtained for the existence of other smaller metastable species, such as C28, C36, and C50, and experimental evidence was provided for “endohedral” complexes, in which an atom was trapped inside the cage. Experiments showed that the size of an encapsulated atom determined the size of the smallest surrounding possible cage. In 1990 physicists Donald R. Huffman of the United States and Wolfgang Krätschmer of Germany announced a simple technique for producing macroscopic quantities of C60, using an electric art between two graphite rods in a helium atmosphere to vaporize carbon. The resulting condensed vapors, when dissolved in organic solvents, yielded crystals of C60. Because they could be received in sufficient amounts, research on this amazing matter could expand to a remarkable degree and the new field of chemistry was born.
Medicine and biological Application
- Antioxidant and neuroprotective activity
- Antiviral activity
- Anticancer treatment, conjugation with proteins and DNA
- Drug delivery and gene delivery
- Photodynamic therapy
- Diagnostic application
- Antimicrobial activity
- Carrier for drug delivery
- Genetic engineering
- Artificial implants
- Diagnostic tool- Due to their ability of fluorescence with specific biomolecules
Application in chemistry, physics, geology and industry
- Solar cells
- In protective eye wear
- Hydrogen gas storage (energy storage)
- Hardening agents
- Cosmetic industry
- Superconductivity in the range 19 to 40 K
- Chemistry – endohedral species
Application in medicine - for medical therapeutics and medical diagnostic
One of the most important use is medicine.
A wide spectrum of applications brings significant benefit. The research is not finished and has great potential to the future.
- Fullerenes are active molecules that can be used as an antioxidant because it can easily react with radicals due to the high affinity of the electron.
- They can make excellent antioxidants. This property can be attributed to the large number of conjugated double bonds they possess and a very high electron affinity of these molecules (due to low energy of the unoccupied molecular orbital).
- They can react with a number of radicals before being consumed. A single C60 molecule can interact with up to 34 methyl radicals before being used up. That is why, these molecules are also known as the 'world's most efficient radical scavengers' or 'radical sponge'. Perhaps, one of the major advantages of using these molecules as an antioxidant is that these can be localized within the cell.
- These molecules also act as effective cytoprotectors against the ultraviolet A irradiation. These bind to the Reactive Oxygen Species (ROS) and prevent damage to cells. A water-soluble derivative C60 with polyvinylpyrrolidone or Radical Sponge is usually added to cosmetics. This prevents skin damage and premature aging of the skin without any side effects. Immediate absorption by the intact skin is the most important advantage of this molecule.
- molecules also prevent lipid peroxidation by scavenging peroxy radicals, and thus, prevent cell cytotoxicity related with them.
- Fullerenes are used as antiviral agents. Its unique molecular structure, antioxidant effect and biological compatibility provides this use.
- Ability to suppress the replication of the HIV virus
Their potential as antiviral agents brought about quite a bit of attention. The most exciting aspect of this may be their ability to suppress the replication of the human immunodeficiency virus (HIV), and thus, delay the onset of acquired immunodeficiency syndrome (AIDS). Dendrofullerene 1 and Derivative 2, transisomer have been seen to inhibit the HIV protease, and thus, prevent replication of HIV 1. Bivalent metal derivatives of amino acid derivatives of fullerene, like C60-1-Ala, are also seen to be active against HIV and human cytomegalovirus replication. These molecules are usually inserted in the hydrophobic domains of proteins (binding site of protease in HIV).
- The reverse transcriptase in HIV, inhibition of hepatitis C virus (HCV)
Another target for their amino acid derivative is the reverse transcriptase in HIV. It is found that these molecules are more active than the non-nucleoside analog inhibitors usually used. Its cationic derivatives are antibacterial and antiproliferative in nature and most of them can inhibit HCV.
- Its water insoluble derivatives show antiviral activities against enveloped viruses, when vesicular stomatitis virus is incubated with fullerene derivatives under visible light, it loses its infectivity. This can be attributed to the generation of singlet oxygen.
- Some fullerenes can form conjugates with proteins and DNA. This situation can help to develop anti-cancer treatments.
- Drug delivery and gene delivery can use fullerene molecules. A chemotherapeutic agent covers their surface. This agent finds the cancer cell and then it is transported directly there.
- Drug delivery is the proper transportation of a pharmaceutical compound to its site of action, whereas gene delivery is the introduction of foreign DNA into cells to bring about a desired effect. It is therefore of utmost importance to deliver these molecules with safety and great efficacy. Fullerenes are a class of inorganic carriers, these molecules are preferred as they show good biocompatibility, greater selectivity, retain the biological activity, and are small enough to be diffused. DNA sequences are attached to the amino acid derivatives of fullerene. These sequences detach from their carrier with the loss or denaturation of the amino groups. Biochemical studies have shown greater protective abilities of these derivatives as compared to the traditional vector used.
- They can be used in the delivery of hydrophobic drugs. In fact, these carriers are used in the slow release of these hydrophobic drugs in the system. A significant anticancer activity has been observed for C60 -paclitaxel conjugate. An additional benefit is that they can easily diffuse through intact skin―a fullerene-based peptide has demonstrated the ability to penetrate via skin.
- Photosensitizers in Photodynamic Therapy
- Photodynamic Therapy (PDT) is a form of therapy of using non-toxic light sensitive compound which, when exposed to light, becomes toxic. PDT can target altered and malignant cells. Fullerenes are usually used as these compounds, they get excited upon irradiation, when these molecules return to ground state; they give off energy that splits the oxygen present to generate singlet oxygen, which can be cytotoxic in nature.
- In the presence of electron donors, they are converted to C60-radicals (excellent acceptors of electrons). These radical anions transfer electrons to oxygen molecules and convert them to anionic superoxide and hydroxyl radicals. These radicals damage the DNA and may bring about cell death. Sometimes, certain fullerenes form conjugates with proteins and DNA; this has a potential application in developing certain anticancer therapy as well.
- The highly water-soluble C60-N vinylpyrrolidone copolymer is used as an agent for photodynamic therapy.
- Possibility to use them for osteoporosis treatment because of its preferential localization
With new chemical entities, the practice of medicine now has the option of molecular therapies requiring next-generation diagnostics and therapeutics. Nanotechnology is used for the creation of useful, functional materials, devices and systems through controlling and manipulating matter at the molecular level.
Fullerenes are exceptional free radical scavengers, or antioxidants. They can intercept free radicals and neutralize them before they cause cellular harm for many diseases, for example:
- Arthritis – interruption of MC (Mast cells) associated diseases.
- Asthma- prevention of MC activation in the lung, so an asthma attack does not occur.
- Allergy - Mast cells (MC) are found in most tissues throughout the body. They have traditionally been associated with initiating and propagating the allergic response. Fullerene derivatives may be capable of blocking this process and, unlike current medications, prevent the allergy reaction before it has a chance to proceed.
Development of the nanomedical fields is in their infancy, especially in the area of carbon-based nanomaterials. The studies exploring the toxicity of fullerenes on human systems are not still finished and are the topic of much debate.
A polymer-based organic photovoltaic cell can solve request to find an economical and lightweight medium for the conversion of solar energy. The principle of these solar cells work is transfer of electrons from a material that gets excited when irradiated with light (the material is the donor). An acceptor molecule takes this electron (in excited state). The molecule is transferred further to the electrode. Fullerenes make excellent acceptors, because they have high electron affinity and ability to transfer electrons. These organic photovoltaic cells are complexes of fullerenes and polymers (bulk heterojunctions).
A common acceptor used in organic solar cells is Phenyl-C61-butyric acid methyl ester (PCBM). It is usually used in conjunction with the polymer polythiophene (P3HT) as an electron donor.
In Protective Eye wear
Fullerenes have optical limiting properties. This refers to its ability to decrease the transmittance of light incident to it. These molecules can therefore be used as an optical limiter that can be used in protective eye-wear and sensors. This optical limiter will only allow the light below a particular threshold to pass through as well as maintain the light being transmitted at a constant level, much below the intensity that may cause damage to the eye or the sensor.
Hydrogen Gas Storage (6.7 m3 of H2 / 1 kg of C60)
Fullerene one-of-a-kind molecular structure make possible to hydrogenate and dehydrogenate quite easily. The carbon rings of this substance are conjugated with C=C double bonds. On hydrogenation, these bonds can be broken easily giving rise to C-C single bonds and C-H bonds. When these hydrides are heated up, the C-H bonds break easily to give back fullerene.
Why? Because the bond strength of C-H is lower as compared to that of C-C.
If we consider 36 hydrogen atoms are held up to with one fullerene molecule, then one kg of it can hold up in normal condition about 6.7 m3 (237.5 ft3) of hydrogen. If means that a classic matchbox in the Czech republic (5.0x3.5x1.5 cm3 or 1.97x1.38x0.59 inch3) full of C60 can hold about 291.2 liter (10.3 cubic feet) of gas hydrogen.
The color of hydrogenate C60 changes in dependence of hydrogen content. The black color changes to brown, red, orange, and finally, to yellow with increasing of H2 content.
These molecules store hydrogen in a better, safer, and more efficient way than devices currently being used.
Fullerenes can represent the future of developing relatively lightweight metals with greater tensile strength, without serious change of the metal ductility, probably because of the small size and high reactivity due to the sp2 hybridization of the carbon. This allows dispersion strengthening metal matrix by their interaction with metals. Its admixture to the lightweight Ti-24.5AI-17N alloy caused a 30% increase in the hardness of the alloy.
- Substitution for a diamond films necessary in various electronic devices. Because fullerenes are quite similar in structure to diamonds, there is a possibility of their conversion to diamonds with minor rearrangement of the carbon atoms. The conversions have been recently demonstrated. Converted fullerenes can be used in various electronic devices.
At present, studies are in progress to examine their potential use in sensors as well in development of molecular conductors. The greatest practical application of these molecules might be in the cosmetic industries at this time
- Fullerenes in cosmetic sector play the important role of an anti-aging agents and anti-damage agents.
Application in chemical engineering, chemistry and physics
The C60 molecule goes through a wide range of unheard of chemical reactions. Next points show some of them.
- Accepting and donation of electrons: Ready to accept and donate electrons – it results to possible applications in batteries and advanced electronic devices.
- Addition of hydrogen or halogen atoms: The molecule readily adds atoms of hydrogen and of the halogen elements. Other groups, such as phenyl (a ring-shaped hydrocarbon derived from benzene, formula C6H5,) can replace the halogen atoms, and open useful routes to a wide spectrum of novel derivatives. Some of these derivatives show advanced materials behavior.
- Superconductivity in the range 19 to 40 K: Especially important are crystalline compounds of C60 with alkali metals and alkaline earth metals. These compounds are the only molecular systems whose superconductivity is at temperatures above 19 K. Observed superconductivity is in the range 19 to 40 K (−254 to −233 °C / −425 to −387 °F).
- Endohedral species: Particularly interesting in chemistry are so-called endohedral species, in which a metal atom (generically designated M) is physically trapped inside a fullerene cage. The resulting compounds (with the formulas M@C60) have been extensively explored. Vaporizing graphite disks or rods impregnated with the selected metal may trap atoms of alkali metals, alkaline earth metals and early lanthanides.
- Helium trapping into fullerene molecule and use in geology or in meteorites exploration:
- Heating C60 in helium vapor under pressure can also be trap helium atoms.
- Minute samples of He@C60 with unusual isotope ratios have been found at some geologic sites.
- Some samples also found in meteorites may yield information on the origin of the bodies in which they were found.
Future potential applications – what are ideas and possibilities of next development?
2 actual disadvantages against 2 advantages
- Still expensive – if you will make a decision to buy C60 you will have to calculate a little
- Their production is very time-consuming,
- Great potential to the future
- They are supposed to use in a lot of branches
Drugs against growing old treatment of Alzheimer’s or Parkinson’s disease
One of their basic property is a capability of multiple additional reactions. Therefore, there is an idea, that their ability to catch all the free radicals could result to drugs against growing old.
Free radicals are associated with human disease, including cancer, atherosclerosis, Alzheimer's disease, Parkinson's disease and many others. They also may have a link to aging, which has been defined as a gradual accumulation of free-radical damage
Inhibitors of AIDS protease – HIV/AIDS treatment
Protease inhibitors (PIs) are a class of antiviral drugs that are widely used to treat HIV/AIDS and hepatitis C. Protease inhibitors prevent viral replication by selectively binding to viral proteases (e.g. HIV-one protease) and blocking proteolytic cleavage of protein precursors that are necessary for the production of infectious viral particles.
Excellent solid lubricants
The discovery of C60 has led to a paradigm shift in the understanding of graphite, in particular graphene sheets on a small scale. It is now known that the most stable form of a carbon aggregate, containing tens to several thousands of atoms, is a closed buckyball or nanotube. This new understanding is not restricted to pure carbon but also applies to other sheet-forming materials such as boron nitride, which can also form nanotubes. Closed structures, incorporating sulfides of such metals as tungsten and molybdenum, exhibit excellent solid-lubricant properties.
Extensive use in electronics and optics
Fullerenes are supposed to use extensively in solar panels, electromagnetic radiation protection
Conducting carbon nanotubes may be coated with sheaths of metal sulfides to produce tiny insulated electrical wire.
Civil engineering, building constructions, constructing aircrafts and cars
Fullerenes and nanotubes have engendered much excitement, especially with regard to possible future applications, but so far, such applications have been rare. Nanotubes in particular may well bring about a revolution in materials science. For example, if SWNTs (single-walled nanotubes) can be made in bundles of 100 billion, then a material will be produced that may approach the limits of tensile strength possible for any known material involving the chemical bond. In practice, no material approaches its theoretical “intrinsic strength,” because of breakdowns brought on by the propagation of microscopic defects through the material. A bundle of nanotubes, however, may bypass this problem, as microscopic defects may anneal along the length of a particular tube and certainly should not propagate across the bundle—thus avoiding the problems that occur in conventional materials.
Estimates of potential tensile strength vary, but it is predicted that a 1-metre rod may reach 50 to 100 times the strength of steel at one-sixth the weight. The impact of such a material on civil engineering, building construction, aircraft, and automobiles would be spectacular.
In order to realize this potential, however, new processes will have to be discovered that can produce long (more than one meter), perfectly ordered bundles in which all 100 billion nanotubes preferably have the same diameter and atomic arrangement. No technology to achieve this exist at present; indeed, it is not even obvious what strategy might be used to reach this goal.
More realistically, carbon-nanotube composite materials exhibiting improved behavior over standard carbon-fibre composites are likely in the near term. In addition, applications on a small scale should be feasible for medical purposes—for instance, the strength of individual nanotubes may prove useful in microsurgery or nanosurgery.
This article is focused to the very interesting topic – to application of fullerenes, mainly buckminsterfullerenes. A short history of their discovery and research in the beginning of the article can help you understand the start and next quick development.
Maybe the summary of properties, applications and potential of these interesting substances has made you think over it more. On the other hand, you may meet some their interesting application personally.
Do you think that the new substance can seriously influence future industry, science, medicine?
Do you think this substance is important and that deserves our attention?
Why are fullerenes good lubricants? Are you interested in this particular application and would you like to know more about it? Fullerenes have absolutely amazing physical and chemical properties and therefore they offer almost infinite list of possible applications.
The use of fullerenes as lubricants, precisely as lubricant additives is one of them.
In this article you will get to know how fullerenes additives improve the attributes of lubricants. It will provide you with all essential information regarding this topic and explain why fullerenes are used as additives in conventional lubricating fluids and not in their crystalline solid state.
The use of nano-additives is a great opportunity how to enhance the performance of lubricant oil.
Nanotechnology is an extremely fast-evolving science. It is already clear nanoparticles are going to play a huge part in the lubricant industry.
Join us and learn more about this exciting topic.
Why Are Fullerenes Good Lubricants – It Is All about Their Structure
You should know that its symmetrical structure set the scientific world on fire. If you look at the model of buckminsterfullerene (formula C₆₀), what you will see is a pure perfection. There are astonishing 120 symmetry operations. In other words buckyball is the most symmetrical molecule of all.
The Early Experiments Proved Fullerenes Additives Could Significantly Improve the Performance of Lubricants
When the scientists realized that they had discovered perfectly symmetrical molecule, they knew it had enormous potential in many applications.
Molecules of spherical shapes suggest they could be good lubricants as they can help reduce friction between microscopically small moving components.
Therefore, when C₆₀ was discovered in 1985, the scientists thought they had found a molecule that could be an ideal lubricant by its own. However, the subsequent experiments did not show such results. But they had realized that C₆₀ molecules could be dissolved in organic solvent toluene.
Such a fullerene enriched fluid significantly reduced the friction between the liquid and the surface through which it flew.
Providing a Proof
Although the scientists did not receive the results they originally hoped for, by series of experiments they had proved that fullerene additives could improve the properties of conventional lubricants.
What they did?
- They started with measuring the attractive, oscillating forces between the pair of smooth and transparent sheets of mica which were immersed in toluene. It is also good to know that the distance between the surfaces was varied.
- Once they added the liquid that contained small amounts of buckyballs, something changed. They observed that C₆₀ molecules had created thin layers on the mica surfaces.
- As a result of that the molecular spheres let the liquid to pass easily between the mica sheets.
- How is it possible? Basically the researchers assumed that the soaked up layer of molecules is not strongly bounded to the surface. The second assumption was that the same as in crystalline solid, the buckminsterfullerenes would be rotating fast so that the toluene molecules could slide by smoothly.
To sum their findings up, the researches made series of experiments which led to the realization that the forces between solid layers of C₆₀ molecules without a liquid do not show any significant reduction in friction. However, they also proved that once they had enriched the conventional lubricating fluids with fullerene additives, the fluid was passing smoothly.
They indicated that fullerene additives are effective way how to enhance the performance of lubricants.
What Are the Properties of Fullerene Lubricant?
- Fullerene additives help to reduce friction.
- They also improve the wear resistance in places where there are rolling and sliding contacts (chains, gears, ball bearings, pumps, artificial joints and screws).
- These molecules can withstand high temperature and pressure without any damage (chemically and physically).
- When incorporated into matrix, they show consistent tribological performance.
- Another positive fact is also a cheaper production comparing to the production of nanodiamond particles.
Their potential as lubricant additives is huge, because a lubricant that is derived from mineral oils or synthetic hydrocarbon blends does not have properties on its own. Therefore adding fullerene nanoparticles is an effective solution to this problem.
3 Main Benefits of Using Fullerene Lubricants
- Saving energy.
- Their use helps extending the operating times.
- They reduce maintenance in automotive, aerospace and medical sectors.
Fullerenes Are Great Promise for the Lubricant Industry
It is quite simple. Nowadays there are developed engines with requirements on high efficiency results. Such an advanced technology needs new and effective engine oils and lubricants which are more durable and show better performance.
Now you are certain that adding fullerene particles into the fluid base strengthens the properties of the lubricant.
You also know what are the properties of fullerene lubricants and benefits of their use.
Do you agree with the statement that they significantly help saving the energy? And do you think we are going to witness their mass production in a near future?
Please share your opinion on this topic with us.
Buckminsterfullerene structure has many outstanding properties, but one of the most striking is its symmetry.
To be accurate there are 120 symmetry operations. In other words it means rotations around the axis and reflections in the plane. And because C60 molecule can show the highest amount of symmetry operations, it is the most symmetric one.
In fact buckyball, with its 60 carbon atoms, is the most symmetrical molecule carbon atom can take.
This beautiful molecule proves to have an enormous potential in various applications.
Let’s learn a bit more about its fascinating structure.
Buckminsterfullerene Structure – The Basic Facts
Buckminsterfullerene also known as C60 molecule or buckyballs was named after famous American architect and futurist, Richard Buckminster “Bucky” Fuller, who designed the geodesic dome, which shape resembles the structure of the C60 molecule.
The molecule is formed by twenty hexagons and twelve pentagons. A carbon atom is at each vertex of each polygon and there is a bond along each polygon edge.
How Does the Buckyball Structure Look Like?
Imagine a soccer (football) ball. It also consists of twenty white hexagons and twelve black pentagons. The shape of the soccer ball resembles the C60 molecule very precisely.
If we compared the size of the buckyball and the soccer ball, it would be the same ratio as if we would compare the soccer ball to the size of the Earth.
More Detailed Description of the Structure of Buckminsterfullerene
Fullerenes are pure carbon molecules that make the cage of carbon atoms and C60 is one of the members of fullerene family.
Considering their structure they can be either closed (buckyballs) or opened (buckytubes).
You can find its structure figures below.
|Crystal Structure||Face-centered cubic, cF1924|
|Space Group||Fm3m, No. 225|
|Lattice Constant||a = 1.4154 nm|
Fullerenes were discovered in 1985 at Rice University by a group of scientists from which three of them were awarded by the Nobel Prize in Chemistry in 1996. In their experiments they let the graphite to undergo the laser ablation.
And that is how they discovered C60 molecule. They found out that this molecule is the most common fullerene.
They saw a perfect molecule. As we already know it consists of twenty hexagons and twelve pentagons where the centers of the pentagons are the corners of icosahedron. To be more precise C60 molecule is a truncated icosahedron. Each of its pentagon shares the edges with the adjacent hexagons.
The fact that the buckyballs are made from closed cages of carbon hexagons and pentagons is supported by two theories:
- Euler’s Formula
- Descartes’ Theore
Based on the theorem of the mathematician Leonhard Euler a spherical surface that is built up from pentagons and hexagons must have exactly twelve pentagons.
You Should Also Know
The C60 molecule is actually the smallest buckyball. It is important to mention that there are no pentagons in contact, which means they do not share a corner or an edge with a neighboring pentagon.
A Helpful Insight into the Structure of the Buckminsterfullerene
There is no doubt that the structure of Buckminsterfullerene is truly revolutionary discovery that excites the scientific world as it suggests great properties that can be used for many applications.
As you already know, this interesting molecule is the most symmetric one and consists of twenty hexagons and twelve pentagons. It is a truncated icosahedron and also the smallest buckyball.
Are you also interested in the C60 molecule structure? You are welcome to share your opinions with us.