Tag Archives: Yashwant Mahajan

The birth of carbon nanotubes (CNTs): a history

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There is a comprehensive history of the carbon nanotube stretching back to prehistory and forward to recent times in a June 3, 2016 Nanowerk Spotlight article by C.K. Nisha and Yashwant Mahajan of the Center of Knowledge Management of Nanoscience & Technology (CKMNT) in India. The authors provide an introduction explaining the importance of CNTs,

Carbon nanotubes (CNTs) have been acknowledged as the material of the 21st century. They possess unique combination of extraordinary mechanical, electronic, transport, electrical and optical, properties and nanoscale sizes making them suitable for a variety of applications ranging from engineering, electronics, optoelectronics, photonics, space, defence industry, medicine, molecular and biological systems and so on and so forth. Worldwide demand for CNTs is increasing at a rapid pace as applications for the material are being matured.

According to MarketsandMarkets (M&M), the global market for carbon nanotubes in 2015 was worth about $2.26 billion1; an increase of 45% from 2009 (i.e. ~ $ 1.24 billion). This was due to the growing potential of CNTs in electronics, plastics and energy storage applications and the projected market of CNTs is expected to be around $ 5.64 billion in 2020.

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In view of the scientific and technological potential of CNTs, it is of immense importance to know who should be credited for their discovery. In the present article, we have made an attempt to give a glimpse into the discovery and early history of this fascinating material for our readers. Thousands of papers are being published every year on CNTs or related areas and most of these papers give credit for the discovery of CNTs to Sumio Iijima of NEC Corporation, Japan, who, in 1991, published a ground-breaking paper in Nature reporting the discovery of multi-walled carbon nanotubes (MWCNTs)2. This paper has been cited over 27,105 times in the literature (as on January 12, 2016, based on Scopus database). This discovery by Iijima has triggered an avalanche of scientific publications and catapulted CNTs onto the global scientific stage.

Nisha and Mahajan then prepare to take us back in time,

In a guest editorial for the journal Carbon, Marc Monthioux and Vladimir L. Kuznetsov3 have tried to clear the air by describing the chronological events that led to the discovery of carbon nanotubes. As one delves deeper into the history of carbon nanotubes, it becomes more apparent that the origin of CNTs could be even pre-historic in nature.

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Recently, Ponomarchuk et al from Russia have reported the presence micro and nano carbon tubes in igneous rocks formed about 250 million years ago4-7. They suggested the possibility of formation of carbon nanotubes during the magmatic processes. It is presumed that the migration of hydrocarbon fluids through the residual melt of the rock groundmass created gas-saturated areas (mostly CH4, CO2, CO) in which condensation and decomposition of hydrocarbon in presence of metal elements resulted in the formation of micro and sub-micron carbon tubes.

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Another most compelling evidence of pre-historic naturally occurring carbon nanotubes (MWCNTs) is based on the TEM studies carried out by Esquivel and Murr8 that analyzed 10,000-year-old Greenland ice core samples and it was suggested that probably they could have been formed during combustion of natural gas/methane during natural processes.

However, the validity of this evidence is questionable owing to the lack of clear high-resolution TEM images, high-quality diffraction patterns or Raman spectroscopy data. In addition, [an]other interesting possibility is that the carbon nanotubes could have been directly formed by the transformation of naturally occurring C60 fullerenes in nature without the assistance of man, given the right conditions prevail. Suchanek et al.,9 have actually demonstrated this thesis, under the laboratory environment, by transforming C60 fullerenes into CNTs under hydrothermal conditions.

There is a large body of evidence in literature about the existence of naturally occurring fullerenes in nature, e.g., coal, carboneous rocks, interstellar media, etc. Since the above experiments were conducted under the simulated geological environment, their results imply that CNTs may form in natural hydrothermal environment.

This hypothesis was further corroborated by Velasco-Santos and co-workers10, when they reported the presence of CNTs in a coal–petroleum mix obtained from an actual oil well, identified by the PEMEX (the Mexican Petroleum Company) as P1, which is located in Mexico’s southeast shore. TEM studies revealed that the coal-petroleum mix contained predominantly end-capped CNTs that are nearly 2 µm long with outer diameter varying between few to several tenths of nanometers.

There’s another study supporting the notion that carbon nanotubes may be formed naturally,

In yet another study, researchers from Germany11 have synthesized carbon nanotubes using igneous rock from Mount Etna lava as both support and catalyst. The naturally occurring iron oxide particles present in Etna lava rock make it an ideal material for growing and immobilizing nanocarbons.

When a mixture of ethylene and hydrogen were passed over the pulverized rocks reduced in a hydrogen atmosphere at 700°C, the iron particles catalyzed the decomposition of ethylene to elemental carbon, which gets deposited on the lava rock in the form of tiny tubes and fibers.
This study showed that if a carbon source is available, CNTs/CNFs can grow on a mineral at moderate temperatures, which directs towards the possibilities of carbon nanotube formation in active suboceanic volcanos or even in interstellar space where methane, atomic hydrogen, carbon oxides, and metallic iron are present.

This fascinating and informative piece was originally published in the January 2016 edition of Nanotech Insights (CKMNT newsletter; scroll down) and can be found there although it may be more easily accessible as the June 3, 2016 Nanowerk Spotlight article where it extends over five (Nanowerk) pages and has a number of embedded images along with an extensive list of references at the end.

Enjoy!

Cement and concrete festival

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Over the last week or so there’ve been a number of articles and publications about cement and concrete and nanotechnology. The Dec. 17, 2012 Nanowerk Spotlight article by (Mohammed) Shakeel Iqbal and Yashwant Mahajan for India’s Centre for Knowledge Management of Nanoscience & Technology (CKMNT, an ARCI [International Advanced Research Centre for Powder Metallurgy and New Materials] project, Dept.of Science & Technology) seemed to kick off the trend with a patent analysis of nanotechnology-enabled cement innovations,

China is the world leader of patent filings, their 154 patent applications contributing 41% of overall filings, representing the major and active R&D player in the area of nano-based cementitious materials. South Korea is the second leading country with 55 patents (15% of patent filings) on nano-enabled cement, closely followed by United States with 51 patents. Russia, Germany, Japan, France and India are the other leading patent filing countries with 37, 18, 11, 9 and 5 patents respectively, while the remaining patents represent a minor contribution from rest of the world.

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Dagestan State University (Russia) is the leading assignee with 15-patents to its credit, which are mainly focussed on the development of heat resistant and high compression strength concrete materials. Halliburton Energy Services Inc (USA) comes second with 14-patents that are directed towards well bore cementing for the gas, oil or water wells using nano-cementitious materials.

This is another teaser article from the CKMNT (see my Dec. 13, 2012 posting about their bio-pharmaceutical teaser article) that highlights the findings from a forthcoming report,

A comprehensive Market Research Report on “Nanotechnology in Cement Industry” is proposed to be released by CKMNT in the near future. Interested readers may please contact Dr. Y. R. Mahajan, Technical Adviser and Editor, Nanotech Insights or Mr. H. Purushotham, Team Leader purushotham@ckmnt.com.

Regardless of one’s feelings about patents and patent systems, the article also provides a  good technology overview of the various nanomaterials used as fillers in cement, courtesy of the information in the filed patents.

A December 20, 2012 news item on Azonano points to at least of the reasons cement is occasioning research interest,

Cement production is responsible for 5% of carbon dioxide emissions. If we are to invent a “green” cement, we need to understand in more detail the legendary qualities of traditional Portland cement. A research group partly financed by the Swiss National Science Foundation (SNSF) is tackling this task.

The Dec. 20, 2012 Swiss National Science Foundation (SNSF) news release, which originated the news item on Azonano, goes on to describe the research into exactly how Portland cement’s qualities are derived,

The researchers first developed a packing model of hydrated calcium silicate nanoparticles. They then devised a method for observing their precipitation based on numerical simulations. This approach has proven successful (*). “We were able to show that the different densities on the nano scale can be explained by the packing of nanoparticles of varying sizes. At this crucial level, the result is greater material hardness than if the particles were of the same size and it corresponds to the established knowledge that, at macroscopic level, aggregates of different sizes form a harder concrete.” [said Emanuela Del Gado, SNSF professor at the Institute for Building Materials of the ETH Zurich]

Until today, all attempts to reduce or partially replace burnt calcium carbonate in the production of cement have resulted in less material hardness. By gaining a better understanding of the mechanisms at the nano level, it is possible to identify physical and chemical parameters and to improve the carbon footprint of concrete without reducing its hardness.

For those of a more technical turn of mind, here’s a citation for the paper (from the SNSF press release),

E. Masoero, E. Del Gado, R. J.-M. Pellenq, F.-J. Ulm, and S. Yip (2012). Nanostructure and Nanomechanics of Cement: Polydisperse Colloidal Packing. Physical Review Letters. DOI: 10.1103/PhysRevLett.109.155503

Meanwhile, there’s a technical group in Spain working on ‘biological’ concrete. From the Dec. 20, 2012 news item on ScienceDaily,

In studying this concrete, the researchers at the Structural Technology Group of the Universitat Politècnica de Catalunya • BarcelonaTech (UPC) have focused on two cement-based materials. The first of these is conventional carbonated concrete (based on Portland cement), with which they can obtain a material with a pH of around 8. The second material is manufactured with a magnesium phosphate cement (MPC), a hydraulic conglomerate that does not require any treatment to reduce its pH, since it is slightly acidic.

On account of its quick setting properties, magnesium phosphate cement has been used in the past as a repair material. It has also been employed as a biocement in the field of medicine and dentistry, indicating that it does not have an additional environmental impact.

The innovative feature of this new (vertical multilayer) concrete is that it acts as a natural biological support for the growth and development of certain biological organisms, to be specific, certain families of microalgae, fungi, lichens and mosses.

Here’s a description of the ‘biological’ concrete and its layers,

In order to obtain the biological concrete, besides the pH, other parameters that influence the bioreceptivity of the material have been modified, such as porosity and surface roughness. The result obtained is a multilayer element in the form of a panel which, in addition to a structural layer, consists of three other layers: the first of these is a waterproofing layer situated on top of the structural layer, protecting the latter from possible damage caused by water seeping through.

The next layer is the biological layer, which supports colonisation and allows water to accumulate inside it. It acts as an internal microstructure, aiding retention and expelling moisture; since it has the capacity to capture and store rainwater, this layer facilitates the development of biological organisms.

The final layer is a discontinuous coating layer with a reverse waterproofing function. [emphasis mine] This layer permits the entry of rainwater and prevents it from escaping; in this way, the outflow of water is redirected to where it is aimed to obtain biological growth

This work is designed for a Mediterranean climate and definitely not for rain forests such as the Pacific Northwest which, climatologically, is a temperate rainforest.

The ScienceDaily news item ends with this information about future research and commercialization,

The research has led to a doctoral thesis, which Sandra Manso is writing. At present, the experimental campaign corresponding to the phase of biological growth is being conducted, and this will be completed at the UPC and the University of Ghent (Belgium). This research has received support from Antonio Gómez Bolea, a lecturer in the Faculty of Biology at the University of Barcelona, who has made contributions in the field of biological growth on construction materials.

At present, a patent is in the process of being obtained for this innovative product, and the Catalan company ESCOFET 1886 S.A., a manufacturer of concrete panels for architectural and urban furniture purposes, has already shown an interest in commercialising the material.

Almost at the same time, the US Transport Research Board (a division of the US National Research Council) released this Dec. 19, 2012 announcement about their latest circular,

TRB Transportation Research Circular E-C170: Nanotechnology in Concrete Materials: A Synopsis explore promising new research and innovations using nanotechnology that have the potential to result in improved mechanical properties, volume change properties, durability, and sustainability in concrete materials.

The report is 44 pp (PDF version) and provides an in-depth look (featuring some case studies) at the research not just of nanomaterials but also nanoelectronics and sensors as features in nanotechoology-enabled concrete and cement products.

There you have it, a festival of cement and concrete.

Turmeric, healing, and nanotechnology

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Turmeric gives its distinctive yellow colour to the type of curry we always ate at home. All these years later, it’s a bit of a surprise to learn that turmeric has healing properties. From the Sept. 13, 2011 news item on MedicalXpress.com,

Curcumin, the main component in the spice turmeric, suppresses a cell signaling pathway that drives the growth of head and neck cancer, according to a pilot study using human saliva by researchers at UCLA’s Jonsson Comprehensive Cancer Center.

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“This study shows that curcumin can work in the mouths of patients with head and neck malignancies and reduce activities that promote cancer growth,” Wang [Dr. Marilene Wang, senior author and professor of head and neck surgery] said. “And it not only affected the cancer by inhibiting a critical cell signaling pathway, it also affected the saliva itself by reducing pro-inflammatory cytokines within the saliva.”

Unfortunately, the amounts used in cooking are not sufficient for a cancer inhibiting effect,

To be effective in fighting cancer, the curcumin must be used in supplement form. Although turmeric is used in cooking, the amount of curcumin needed to produce a clinical response is much larger. Expecting a positive effect through eating foods spiced with turmeric is not realistic, Wang said.

There is a bit of a downside to the type of supplement they used in this study,

The curcumin was well tolerated by the patients and resulted in no toxic effects. The biggest problem was their mouths and teeth turned bright yellow.

As you might expect, the next study will be for a longer period,

The next step for Wang and her team is to treat patients with curcumin for longer periods of time to see if the inhibitory effects can be increased. They plan to treat cancer patients scheduled for surgery for a few weeks prior to their procedure. They’ll take a biopsy before the curcumin is started and then at the time of surgery and analyze the tissue to look for differences.

“There’s potential here for the development of curcumin as an adjuvant treatment for cancer,” Wang said. “It’s not toxic, well tolerated, cheap and easily obtained in any health food store. While this is a promising pilot study, it’s important to expand our work to more patients to confirm our findings.”

There have been two feature articles on Nanowerk about curcumin, its healing properties, which extend beyond treating head and neck cancer, and patents during fall 2011. From the Sept. 8, 2011 article, Nanotechnology-enhanced curcumin: Symbiosis of ancient wisdom of the East with modern medical science [Note: I have removed citation notes],

Turmeric (Curcuma longa L.) is the shining star among the cornucopia of traditional medicinal plants. It has a long history of usage in traditional medicine in India and China. Ancient Indians have known the medicinal properties of turmeric, thus curcumin, for several millennia.

The cultivation of turmeric plants began in Harappan civilization in 3000 BC and Susruta Samhita, dating back to 250 BC, highly recommends use of an ointment based on turmeric for relieving food poisoning effect. Turmeric was introduced to China from India by 700 A.D. and has been said to be long used as a medicinal herb. It has been used in Ayurvedic medicines internally as a stomach tonic and blood purifier, and topically in the prevention and treatment of skin diseases.

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In the scientific literature there is a large body of evidence showing that curcuminoids exhibit a broad spectrum of biological and pharmacological activities including anti-oxidant, anti-inflammatory, anti-bacterial, anti-fungal, anti-parasitic, anti-mutagen, anti-cancer and detox properties. Curcumin’s unique ability to work through so many different pathways with its extraordinary antioxidant and anti-inflammatory attributes can have a positive influence in combating almost every known disease.

Extensive studies carried out by researchers around the globe have clearly demonstrated curcumin’s great potential as a thercurcuminapeutic agent, and have paved the way towards conducting clinical trials for a variety of diseases including cancer, cardiovascular, neurological and gastrointestinal disorders, multiple sclerosis, diabetes type II, skin diseases, cystic fibrosis, cataract etc.  [Note: There is also an extensive discussion of cancer treatment included in this article.]

Here are the active components (as understood by scientists currently),

The bio-active polyphenol component of turmeric is curcumin, also known as diferuloylmethane (C21H20O6), with an ability to prevent and cure diseases. Turmeric contains about 2-5% curcumin alone. Commercial curcumin contains three main types of curcuminoids, i.e., curcumin (diferuloylmethane or”Curcumin I” about 77%), demethoxy curcumin (“Curcumin II” ∼17%) and bis demethoxy curcumin (“Curcumin III” ∼3%)). Curcumin (diferuloylmethane renders its bright yellow color to turmeric. In addition to natural curcumin, several analogues of curcumin have been synthesized and studied. These include tetrahydrocurcumin (antioxidative), 4-hydroxy-3-methoxybenzoic acid methyl ester (HMBME), aromatic enone and dienone analogues, metal chelates of synthetic curcuminoids etc.

There has already been one court case regarding a curcumin patent,

Recently, turmeric came into the global limelight when the controversial patent “Use of Turmeric in Wound Healing” was awarded, in 1995, to the University of Mississippi Medical Center, USA. Indian Council of Scientific and Industrial Research (CSIR) aggressively contested this award of the patent. It was argued by them that turmeric has been an integral part of the traditional Indian medicinal system over several centuries, and therefore, is deemed to be ‘prior art’, hence is in the public domain. Subsequently, after protracted technical/legal battle USPTO decreed that turmeric is an Indian discovery and revoked the patent.

I wonder if this will set a precedent for other herbs and plants that are associated with specific cultures or indigenous groups as part of their healing tradition. Much of our modern pharamcopoeia is derived from traditional healing plants and the people who shared that knowledge have not shared in the benefits that large pharmaceutical companies have reaped.

Back to the curcumin and the issue of low bioavailability (in Wang’s study mentioned earlier, patients were given 2 tablets totaling 1000 miligrams of curcumin and it seems that was done once),

In practice, only very low or undetectable levels of curcumin can be achieved in blood by oral administration of curcumin. The low bioavailability of curcumin has been attributed to its very low aqueous solubility, tendency to degrade in the gastroinenstinal tract in the physiological environment, high rate of metabolism, and rapid systemic elimination. The low bioavailability of curcumin has so far limited its medical use. It has been suggested that a person is required to consume large doses (about 12-20g/day) of curcumin in order to achieve its therapeutic effects on the human body. That means one has to swallow 24 to 40 curcumin capsules of 500mg each. These doses are considered to be too high, and therefore, not feasible to be incorporated in clinical trials due to unbearable after-taste to the palate, possibility of giving rise to nauseatic feeling and perceived toxicity issues.

Therefore, to achieve the maximum response of this potentially useful chemopreventive agent, a number of approaches such as the use of adjuvants like piperine, synthetic analogues, chelating of curcumin with metals, combination with other dietary agents etc. have been investigated. Nanotechnology-based novel strategies are being aggressively explored worldwide to enhance curcumin’s bioavailability and reduce perceived toxicity as they offer several other additional benefits such as improved cellular uptake, enhanced dissolution rates, excellent blood stability, controlled release functions, multifunctional design, enhancement in its pharmacological activities (e.g. antioxidant and antihepatoma activities) etc.

This article and the Dec. 22, 2011 article, Nanotechnology-enhanced curcumin – literature and patent analysis, on Nanowerk were both written by Dr. Yashwant Mahajan (by himself for the Sept. 8  article and with Ratnesh Kumar Gaur for the Dec. 22 article), Centre for Knowledge Management of Nanoscience and Technology (CKMNT). There is more detail about the nanotechnology-based strategies to increase bioavailability in the Dec. 22, 1011 article,

These approaches include solid-lipid nanoparticles, nanosuspension, nanoemulsion, cyclodextrin curcumin self assembly, hydrogel nanoparticles, curcumin-phospholipid complex and curcumin incorporated within polymer nanoparticles. The figure below shows these various nano-based approaches for drug delivery of curcumin in the form of a pie chart and this survey is based on 124 relevant patents for the period from 2001 to 2010. As depicted in this pie chart [in the article on Nanowerk] polymer nanoparticles play a dominant role (34%) followed by curcumin nanoemulsion (20%), nanosuspension (13%), phospholipids complex (12%), cyclodextrin curcumin self-assembly, hydrogel NPs and SLNs in decreasing order. The polymer nanoparticles-incorporated drug delivery systems are further subdivided into various classes of polymers such as generic polymers, liposomal, PEG, micelle, PLGA, and as can be seen, generic polymers, liposomal, PEG and micelle play a dominant role in decreasing order.

Curcumin is still being patented but it seems the focus on delivering curcumin more efficiently for therapeutic use,

The analysis reveals that Laila Pharmaceuticals Private Ltd., Chennai, India is the world leader with 8 patent applications to their credit and their main focus is on nanoemulsification of curcumin and its derivatives. Second in the ranking are Johns Hopkins University, USA, and University of North Texas, USA with 7 patent applications each to their credit and their inventions are directed towards use of polymer nanoparticle encapsulated curcumin and curcumin loaded with PLGA-nanoparticles, respectively. The analysis has also revealed that R&D institutes, universities and only a few small bio and pharma companies such as Laila Pharmaceuticals, Magforce Nanotechnologies, Bioderm Research, Nano Cutting Edge Technologies etc. are involved in the patenting activity.

I did check out the Centre for Knowledge Management of Nanoscience and Technology (CKMNT) where Dr. Mahajan works and which was launched in 2009. From the About Us page,

CKMNT was launched on 1st April 2009 at Hyderabad by the International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI) as one of its project centres. The centre has been set up to foster the exchange and dissemination of advanced technological knowledge and expertise to meet the needs of the nanoresearchers, industry, policy makers, financial institutions and venture capitalists. CKMNT has been partially funded by the Department of Science and Technology (DST), Govt. of India in a project mode and would help in fulfilling the objectives of the Nano Mission of DST.

The Centre’s team is made up of metallurgy and chemical engineering experts, none of whom seem to have worked in medicine or health care, which makes this interest in turmeric a little surprising.