Tag Archives: nanodiamonds

Nanodiamond-embedded membrane filters for clean water

This December 9, 2020 news item on Nanowerk announces research into a nanodiamond filter which can clean hot wastewater,

Although most of the planet is covered by water, only a fraction of it is clean enough for humans to use. Therefore, it is important to recycle this resource whenever possible. Current purification techniques cannot adequately handle the very hot wastewater generated by some industries.

A December 9, 2020 American Chemical Society (ACS) news release, which originated the news item, provides more detail,

Some oil recovery methods and other industrial processes result in hot wastewater, which requires energy-intensive cooling before it can be purified through traditional reverse osmosis membranes. After purification, the water then needs to be heated before it can be re-used. At such high temperatures, traditional reverse osmosis membranes filter slowly, allowing more salts, solids and other contaminants to get through. Researchers have embedded extremely tiny nanodiamonds — carbon spheres produced by explosions in small, closed containers without oxygen present — onto these membranes in previous studies. Although the membranes effectively and quickly filtered large volumes of water and can protect against fouling, they were not tested with very hot samples. To optimize the membranes for use with hot wastewater, Khorshidi, Sadrzadeh and colleagues wanted to modify the nanodiamond spheres and embed them in a new way.

The team attached amines to nanodiamonds and bathed them in an ethyl acetate solution to prevent the spheres from clumping. Then, a monomer was added that reacted with the amines to create chemical links to the traditional membrane base. Synergistic effects of the amine links and the ethyl acetate treatment resulted in thicker, more temperature-stable membranes, contributing to improvements in their performance. By increasing the amount of amine-enhanced nanodiamonds in the membrane, the researchers obtained higher filtration rates with a greater proportion of impurities being removed, even after 9 hours at 167 F, when compared to membranes without nanodiamonds. The new method produced membranes that could more effectively treat wastewater at high temperatures, the researchers say.

The authors acknowledge funding from Canada’s Oil Sands Innovation Alliance and The Natural Sciences and Engineering Research Council of Canada (NSERC).

Here’s a link to and a citation for the paper,

Nanodiamond-Enabled Thin-Film Nanocomposite Polyamide Membranes for High-Temperature Water Treatment by Pooria Karami, Behnam Khorshidi, Laleh Shamaei, Eric Beaulieu, João B. P. Soares, and Mohtada Sadrzadeh. ACS Appl. Mater. Interfaces 2020, 12, 47, 53274–53285 DOI: https://doi.org/10.1021/acsami.0c15194 Publication Date: November 10, 2020 Copyright © 2020 American Chemical Society

This paper is behind a paywall.

Natural nanodiamonds found in the ocean

An Oct. 16, 2020 news item on phys.org announces research that contradicts a common belief about how diamonds are formed ,

Natural diamonds can form through low pressure and temperature geological processes on Earth, as stated in an article published in the journal Geochemical Perspectives Letters. The newfound mechanism, far from the classic view on the formation of diamonds under ultra-high pressure, is confirmed in the study, which draws on the participation of experts from the Mineral Resources Research Group of the Faculty of Earth Sciences of the University of Barcelona (UB).

Other participants in the study are the experts from the Institute of Nanoscience and Nanotechnology of the UB (IN2UB), the University of Granada (UGR), the Andalusian Institute of Earth Sciences (IACT), the Institute of Ceramics and Glass (CSIC), and the National Autonomous University of Mexico (UNAM). The study has been carried out within the framework of the doctoral thesis carried out by researcher Núria Pujol-Solà (UB), first author of the article, under the supervision of researchers Joaquín A. Proenza (UB) and Antonio García-Casco (UGR).

An Oct. 9, 2020 University of Barcelona (UB) press release (also on EurekAlert but published Oct. 16, 2020), which originated the news item, further explains the research,

A symbol of luxury and richness, the diamond (from the Greek αδ?μας, “invincible”) is the most valuable gem and the toughest mineral (value of 10 in Mohs scale). It formed by chemically pure carbon, and according to the traditional hypothesis, it crystalizes the cubic system under ultra-high-pressure conditions at great depths in the Earth’s mantle.

The study confirms for the first time the formation of the natural diamond under low pressures in oceanic rocks in the Moa-Baracoa Ophiolitic Massif, in Cuba. This great geological structure is in the north-eastern side of the island and is formed by ophiolites, representative rocks of the Oceanic lithosphere.

These oceanic rocks were placed on the continental edge of North America during the collision of the Caribbean oceanic island arch, between 70 and 40 million years ago. “During its formation in the abysmal marine seafloors, in the cretaceous period -about 120 million years ago-, these oceanic rocks underwent mineral alterations due to marine water infiltrations, a process that led to small fluid inclusions inside the olivine, the most common mineral in this kind of rock”, note Joaquín A. Proenza, member of the Department of Mineralogy, Petrology and Applied Geology at the UB and principal researcher of the project in which the article appears, and Antonio García-Casco, from the Department of Mineralogy and Petrology of the UGR.

“These fluid inclusions contain nanodiamonds -of about 200 and 300 nanometres-, apart from serpentine, magnetite, metallic silicon and pure methane. All these materials have formed under low pressure (<200 MPa) and temperature (<350 ºC), during the olivine alteration that contains fluid inclusions”, add the researchers.

“Therefore, this is the first description of ophiolitic diamond formed under low pressure and temperature, whose formation under natural processes does not bear any doubts”, they highlight.

Diamonds formed under low pressure and temperature

It is notable to bear in mind that the team published, in 2019, a first description of the formation of ophiolitic diamonds under low pressure conditions (Geology), a study carried out as part of the doctoral thesis by the UB researcher Júlia Farré de Pablo, supervised by Joaquín A. Proenza and the UGR professor José María González Jiménez. This study was highly debated on among the members of the international scientific community.

In the published article in Geochemical Perspectives Letters, a journal of the European Association of Geochemistry, the experts detected the nanodiamonds in small fluid inclusions under the surface of the samples. The finding was carried out by using the confocal Raman maps and using focused ion beams (FIB), combined with transmission electron microscopy (FIB-TEM). This is how they could confirm the presence of the diamond in the depth of the sample, and therefore, the formation of a natural diamond under low pressure in exhumed oceanic rocks. The Scientific and Technological Centres of the UB (CCiTUB) have taken part in this study, among other infrastructures supporting the country.

In this case, the study focuses its debate on the validity of some geodynamic models that, based on the presence of ophiolite diamonds, imply circulation in the mantle and large-scale lithosphere recycling. For instance, the ophiolitic diamond was thought to reflect the passing of ophiolitic rocks over the deep earth’s mantle up to the transition area (210-660 km deep) before settling into a normal ophiolite formed under low pressure (~10 km deep).

According to the experts, the low state of oxidation in this geological system would explain the formation of nano-çdiamonds instead of graphite -which would be expected under physical and chemical formation conditions of fluid inclusions.

The study counted on the support from the former Ministry for Economy and Competitiveness (MINECO), the Ramón y Cajal Program and the EU European Regional Development Fund (ERDF).

The researchers have an image showing inclusions which contain nanodiamonds,

Caption: The fluid inclusions inside the olivine contain nanodiamonds, apart from serpentine, magnetite, metallic silicon and pure methane.. Credit: UNIVERSITY OF BARCELONA

Here`s a link to and a citation for the paper,

Diamond forms during low pressure serpentinisation of oceanic lithosphere by
N. Pujol-Solà, A. Garcia-Casco, J.A. Proenza, J.M. González-Jiménez, A. del Campo, V. Colás, À. Canals, A. Sánchez-Navas, J. Roqué-Rosell. Geochemical Perspectives Letters v15 DOI: 10.7185/geochemlet.2029 Published 10 September 2020

This paper is open access.

Oily nanodiamonds

Nanodiamonds if successfully extracted from oil could be used for imaging and communications and the world’s leading program for extracting nanodiamonds (also known as diamondoids) is in California (US). From a May 12, 2016 news item on Nanowerk,

Stanford and SLAC National Accelerator Laboratory jointly run the world’s leading program for isolating and studying diamondoids — the tiniest possible specks of diamond. Found naturally in petroleum fluids, these interlocking carbon cages weigh less than a billionth of a billionth of a carat (a carat weighs about the same as 12 grains of rice); the smallest ones contain just 10 atoms.

Over the past decade, a team led by two Stanford-SLAC faculty members — Nick Melosh, an associate professor of materials science and engineering and of photon science, and Zhi-Xun Shen, a professor of photon science and of physics and applied physics – has found potential roles for diamondoids in improving electron microscope images, assembling materials and printing circuits on computer chips. The team’s work takes place within SIMES, the Stanford Institute for Materials and Energy Sciences, which is run jointly with SLAC.

Close-up of purified diamondoids on a lab bench. Too small to see with the naked eye, diamondoids are visible only when they clump together in fine, sugar-like crystals like these. Photo: Christopher Smith, SLAC National Accelerator Laboratory

Close-up of purified diamondoids on a lab bench. Too small to see with the naked eye, diamondoids are visible only when they clump together in fine, sugar-like crystals like these. Photo: Christopher Smith, SLAC National Accelerator Laboratory

A March 31, 2016 Stanford University news release by Glennda Chui, which originated the news item, describes the work in more detail,

Before they can do that [use nanodiamonds in imaging and other applications], though, just getting the diamondoids is a technical feat. It starts at the nearby Chevron refinery in Richmond, California, with a railroad tank car full of crude oil from the Gulf of Mexico. “We analyzed more than a thousand oils from around the world to see which had the highest concentrations of diamondoids,” says Jeremy Dahl, who developed key diamondoid isolation techniques with fellow Chevron researcher Robert Carlson before both came to Stanford — Dahl as a physical science research associate and Carlson as a visiting scientist.

The original isolation steps were carried out at the Chevron refinery, where the selected crudes were boiled in huge pots to concentrate the diamondoids. Some of the residue from that work came to a SLAC lab, where small batches are repeatedly boiled to evaporate and isolate molecules of specific weights. These fluids are then forced at high pressure through sophisticated filtration systems to separate out diamondoids of different sizes and shapes, each of which has different properties.

The diamondoids themselves are invisible to the eye; the only reason we can see them is that they clump together in fine, sugar-like crystals. “If you had a spoonful,” Dahl says, holding a few in his palm, “you could give 100 billion of them to every person on Earth and still have some left over.”

Recently, the team started using diamondoids to seed the growth of flawless, nano-sized diamonds in a lab at Stanford. By introducing other elements, such as silicon or nickel, during the growing process, they hope to make nanodiamonds with precisely tailored flaws that can produce single photons of light for next-generation optical communications and biological imaging.

Early results show that the quality of optical materials grown from diamondoid seeds is consistently high, says Stanford’s Jelena Vuckovic, a professor of electrical engineering who is leading this part of the research with Steven Chu, professor of physics and of molecular and cellular physiology.

“Developing a reliable way of growing the nanodiamonds is critical,” says Vuckovic, who is also a member of Stanford Bio-X. “And it’s really great to have that source and the grower right here at Stanford. Our collaborators grow the material, we characterize it and we give them feedback right away. They can change whatever we want them to change.”

Crowdfund nano spies for cancer

University of Groningen (Netherlands) researcher, Romana Schirhagl, is crowdfunding her development of a new technique (using nanodiamonds) for biomedical research which would allow observation of free radicals in cells. From a June 25, 2015 news item on Nanowerk,

Romana Schirhagl, a researcher at the University Medical Center Groningen, is hoping to garner public support for a new form of cancer research. Schirhagl wants to introduce miniscule diamonds into living cancer cells. Like spies, these nanodiamonds will be on a mission to reveal the secrets of the cell. Schirhagl applies a unique combination of knowledge and techniques from physics, chemistry and medicine in the research. This could form the basis of new and improved cancer drugs.

A June 16, 2015 University of Groningen press release, which originated the news item, provides background information for the research,

The research of Schirhagl and her research group in the department of Biomedical Engineering focuses on the behaviour of free radicals in a cell. These radicals have an important role in the body. They are sometimes extremely useful, as in the immune system, where they help fight bacteria and viruses, but sometimes very harmful, as when they actually harm healthy cells and can cause cancer. As the radicals only exist for a fraction of a second, it is difficult to tell them apart and study them.

New technique

Schirhagl wants to apply a new technique that currently is mainly used in fundamental physics but looks extremely promising for biomedical research. The technique is based on very small diamonds that can ‘sense’ the presence of magnetic fields from the radicals. The nanodiamonds are fluorescent and change in luminosity as a response to their environment. This makes it easier to determine which radicals occur when and how they work. This information should make it possible to improve cancer drugs – which themselves sometimes use free radicals – or even develop new ones.

Unexpectedly, the crowdfunding platform is the University of Groningen’s own. You can find out more about Nano spies here. To date the project has raised over 6,600 Euros towards a goal of 20,000 Euros.

Nanodiamond alternative to organic fluorophores to view inside living human cells

No sooner is a Nobel prize (2014) awarded for nanoscopy which makes use of fluorescence to observe processes in living cells than there is an announcement about a new technique that avoids fluorescence and its attendant shortcomings. From an Oct. 27, 2014 news item on Nanowerk (Note: A link has been removed),

Nanodiamonds are providing scientists with new possibilities for accurate measurements of processes inside living cells with potential to improve drug delivery and cancer therapeutics.

Published in Nature Nanotechnology (“Coherent anti-Stokes Raman scattering microscopy of single nanodiamonds”), researchers from Cardiff University have unveiled a new method for viewing nanodiamonds inside human living cells for purposes of biomedical research.

An Oct. 27, 2014 Cardiff University (Wales) news release, which originated the news item, explains why the use of nanodiamonds is superior to the use of organic flurophores,

Nanodiamonds are very small particles (a thousand times smaller than human hair) and because of their low toxicity they can be used as a carrier to transport drugs inside cells. They also show huge promise as an alternative to the organic fluorophores usually used by scientists to visualise processes inside cells and tissues.

A major limitation of organic fluorophores is that they have the tendency to degrade and bleach over time under light illumination. This makes it difficult to use them for accurate measurements of cellular processes. Moreover, the bleaching and chemical degradation can often be toxic and significantly perturb or even kill cells.

There is a growing consensus among scientists that nanodiamonds are one of the best inorganic material alternatives for use in biomedical research, because of their compatibility with human cells, and due to their stable structural and chemical properties.

Previous attempts by other research teams to visualise nanodiamonds under powerful light microscopes have run into the obstacle that the diamond material per se is transparent to visible light. Locating the nanodiamonds under a microscope had relied on tiny defects in the crystal lattice, which fluoresce under light illumination.

Production of the defects proved both costly and difficult to realise in a controlled way. Furthermore, the fluorescence light emitted by these defects, and in turn the image gleaned from the microscopic exploration of these flawed nanodiamonds, is sometimes also unstable.

In their latest paper, researchers from Cardiff University’s Schools of Biosciences and Physics showed that non-fluorescing nanodiamonds (diamonds without defects) can be imaged optically and far more stably via the interaction between the illuminating light and the vibrating chemical bonds in the diamond lattice structure which results in scattered light at a different colour.

The paper describes how two laser beams beating at a specific frequency are used to drive chemical bonds to vibrate in sync. One of these beams is then used to probe this vibration and generate a light, called coherent anti-Stokes Raman scattering (CARS).

By focusing these laser beams onto the nanodiamond, a high-resolution CARS image is generated. Using an in-house built microscope, the research team was able to measure the intensity of the CARS light on a series of single nanodiamonds of different sizes.

The nanodiamond size was accurately measured by means of electron microscopy and other quantitative optical contrast methods developed within the researcher’s lab. In this way, they were able to quantify the relationship between the CARS light intensity and the nanoparticle size.

Consequently, the calibrated CARS signal enabled the team to analyse the size and number of nanodiamonds that had been delivered into living cells, with a level of accuracy hitherto not achieved by other methods.

Professor Paola Borri from the School of Biosciences, who led the study, said: “This new imaging modality opens the exciting prospect of following complex cellular trafficking pathways quantitatively with important applications in drug delivery. The next step for us will be to push the technique to detect nanodiamonds of even smaller sizes than what we have shown so far and to demonstrate a specific application in drug delivery.”

Here’s a link to and a citation for the paper,

Coherent anti-Stokes Raman scattering microscopy of single nanodiamonds by Iestyn Pope, Lukas Payne, George Zoriniants, Evan Thomas, Oliver Williams, Peter Watson, Wolfgang Langbein, & Paola Borri. Nature Nanotechnology (2014) doi:10.1038/nnano.2014.210 Published online 12 October 2014

The paper is behind a paywall but there is a free preview with ReadCube Access.

For anyone who’d like to read more about fluorescence and its use in nanoscopy there’s my Oct. 8, 2014 posting about the 2014 Nobel Prize in Chemistry and in my Oct. 27, 2014 posting about a specific use for determining how bipolar disorder may affect the brain.

13,000 year old nanodiamonds and a scientific controversy about extinction

It took scientists from several countries and institutions seven years to reply to criticism of their 2007 theory which posited that a comet exploded over the earth’s surface roughly 13,000 years ago causing mass extinctions and leaving nano-sized diamonds in a layer of the earth’s crust. From a Sept. 1, 2014 news item on Azonano,

Tiny diamonds invisible to human eyes but confirmed by a powerful microscope at the University of Oregon are shining new light on the idea proposed in 2007 that a cosmic event — an exploding comet above North America — sparked catastrophic climate change 12,800 years ago.

In a paper appearing online ahead of print in the Journal of Geology, scientists from 21 universities in six countries report the definitive presence of nanodiamonds at some 32 sites in 11 countries on three continents in layers of darkened soil at the Earth’s Younger Dryas boundary.

The scientists have provided a map showing the areas with nanodiamonds,

The solid line defines the current known limits of the Younger Dryas Boundary field of cosmic-impact proxies, spanning 50 million square kilometers. [downloaded from http://www.news.ucsb.edu/2014/014368/nanodiamonds-are-forever#sthash.FtKG6WwS.dpuf]

The solid line defines the current known limits of the Younger Dryas Boundary field of cosmic-impact proxies, spanning 50 million square kilometers. [downloaded from http://www.news.ucsb.edu/2014/014368/nanodiamonds-are-forever#sthash.FtKG6WwS.dpuf]

 An Aug. 28,, 2014 University of Oregon news release, which originated the Azonano news item, describes the findings and the controversy,

The boundary layer is widespread, the researchers found. The miniscule diamonds, which often form during large impact events, are abundant along with cosmic impact spherules, high-temperature melt-glass, fullerenes, grape-like clusters of soot, charcoal, carbon spherules, glasslike carbon, heium-3, iridium, osmium, platinum, nickel and cobalt.

The combination of components is similar to that found in soils connected with the 1908 in-air explosion of a comet over Siberia and those found in the Cretaceous-Tertiary Boundary (KTB) layer that formed 65 million years ago when a comet or asteroid struck off Mexico and wiped out dinosaurs worldwide.

In the Oct. 9, 2007, issue of Proceedings of the National Academy of Sciences, a 26-member team from 16 institutions proposed that a cosmic impact event set off a 1,300-year-long cold spell known as the Younger Dryas. Prehistoric Clovis culture was fragmented, and widespread extinctions occurred across North America. Former UO researcher Douglas Kennett, a co-author of the new paper and now at Pennsylvania State University, was a member of the original study.

In that [2007] paper and in a series of subsequent studies, reports of nanodiamond-rich soils were documented at numerous sites. However, numerous critics refuted the findings, holding to a long-running theory that over-hunting sparked the extinctions and that the suspected nanodiamonds had been formed by wildfires, volcanism or occasional meteoritic debris, rather than a cosmic event.

The University of Oregon news release goes on to provide a rejoinder from a co-author of both the 2007 paper and the 2014 paper. as well as. a discussion of how the scientists gathered their evidence,

The glassy and metallic materials in the YDB layers would have formed at temperatures in excess of 2,200 degrees Celsius and could not have resulted from the alternative scenarios, said co-author James Kennett, professor emeritus at the University of California, Santa Barbara, in a news release. He also was on the team that originally proposed a comet-based event.

In the new paper, researchers slightly revised the date of the theorized cosmic event and cited six examples of independent research that have found consistent peaks in the creation of the nanodiamonds that match their hypothesis.

“The evidence presented in this paper rejects the alternate hypotheses and settles the debate about the existence of the nanodiamonds,” said the paper’s corresponding author Allen West of GeoScience Consulting of Dewey, Arizona. “We provide the first comprehensive review of the state of the debate and about YDB nanodiamonds deposited across three continents.”

West worked in close consultation with researchers at the various labs that conducted the independent testing, including with co-author Joshua J. Razink, operator and instrument manager since 2011 of the UO’s state-of-the-art high-resolution transmission electron microscope (HR-TEM) in the Center for Advanced Materials Characterization in Oregon (CAMCOR).

Razink was provided with samples previously cited in many of the earlier studies, as well as untested soil samples delivered from multiple new sites. The samples were placed onto grids and analyzed thoroughly, he said.

“These diamonds are incredibly small, on the order of a few nanometers and are invisible to the human eye and even to an optical microscope,” Razink said. “For reference, if you took a meter stick and cut it into one billion pieces, each of those pieces is one nanometer. The only way to really get definitive characterization that these are diamonds is to use tools like the transmission electron microscope. It helps us to rule out that the samples are not graphene or copper. Our findings say these samples are nanodiamonds.”

In addition to the HR-TEM done at the UO, researchers also used standard TEM, electron energy loss spectroscopy (EELS), energy-dispersive X-ray spectroscopy (EDS), selected area diffraction (SAD), fast Fourier transform (FFT) algorithms, and energy-filtered transmission electron microscopy (EFTEM).

“The chemical processing methods described in the paper,” Razink said, “lay out with great detail the methodology that one needs to go through in order to prepare their samples and identify these diamonds.”

The University of California at Santa Barbara (UCSB) produced an Aug. 28, 2014 news release about this work and while there is repetition, there is additional information such as a lede describing some of what was made extinct,

Most of North America’s megafauna — mastodons, short-faced bears, giant ground sloths, saber-toothed cats and American camels and horses — disappeared close to 13,000 years ago at the end of the Pleistocene period. …

An Aug. 27, 2014 news item (scroll down to the end) on ScienceDaily provides a link and a citation to the latest paper.

Nanodiamond contact lenses in attempt to improve glaucoma treatment

A School of Dentistry, at the University of California at Los Angeles (UCLA) or elsewhere, is not my first thought as a likely source for work on improving glaucoma treatment—it turns out that I’m a bit shortsighted (pun intended).  A Feb. 14, 2014 news item on Azonano describes the issue with glaucoma treatment and a new delivery system for it developed by a research team at UCLA,

By 2020, nearly 80 million people are expected to have glaucoma, a disorder of the eye that, if left untreated, can damage the optic nerve and eventually lead to blindness.

The disease often causes pressure in the eye due to a buildup of fluid and a breakdown of the tissue that is responsible for regulating fluid drainage. Doctors commonly treat glaucoma using eye drops that can help the eye drain or decrease fluid production.

Unfortunately, patients frequently have a hard time sticking to the dosing schedules prescribed by their doctors, and the medication — when administered through drops — can cause side effects in the eye and other parts of the body.

In what could be a significant step toward improving the management of glaucoma, researchers from the UCLA School of Dentistry have created a drug delivery system that may have less severe side effects than traditional glaucoma medication and improve patients’ ability to comply with their prescribed treatments. The scientists bound together glaucoma-fighting drugs with nanodiamonds and embedded them onto contact lenses. The drugs are released into the eye when they interact with the patient’s tears.

The new technology showed great promise for sustained glaucoma treatment and, as a side benefit, the nanodiamond-drug compound even improved the contact lenses’ durability.

The Feb. 13, 2014 UCLA news release by Brianna Deane, which originated the news item, describes the nanodiamonds and how they were employed in this project,

Nanodiamonds, which are byproducts of conventional mining and refining processes, are approximately five nanometers in diameter and are shaped like tiny soccer balls. They can be used to bind a wide spectrum of drug compounds and enable drugs to be released into the body over a long period of time.

To deliver a steady release of medication into the eye, the UCLA researchers combined nanodiamonds with timolol maleate, which is commonly used in eye drops to manage glaucoma. When applied to the nanodiamond-embedded lenses, timolol is released when it comes into contact with lysozyme, an enzyme that is abundant in tears.

“Delivering timolol through exposure to tears may prevent premature drug release when the contact lenses are in storage and may serve as a smarter route toward drug delivery from a contact lens.” said Kangyi Zhang, co-first author of the study and a graduate student in Ho’s lab.

One of the drawbacks of traditional timolol maleate drops is that as little as 5 percent of the drug actually reaches the intended site. Another disadvantage is burst release, where a majority of the drug is delivered too quickly, which can cause significant amounts of the drug to “leak” or spill out of the eye and, in the most serious cases, can cause complications such as an irregular heartbeat. Drops also can be uncomfortable to administer, which leads many patients to stop using their medication.

But the contact lenses developed by the UCLA team successfully avoided the burst release effect. The activity of the released timolol was verified by a primary human-cell study.

“In addition to nanodiamonds’ promise as triggered drug-delivery agents for eye diseases, they can also make the contact lenses more durable during the course of insertion, use and removal, and more comfortable to wear,” said Ho, who is also a professor of bioengineering and a member of the Jonsson Comprehensive Cancer Center and the California NanoSystems Institute.

Even with the nanodiamonds embedded, the lenses still possessed favorable levels of optical clarity. And, although mechanical testing verified that they were stronger than normal lenses, there were no apparent changes to water content, meaning that the contact lenses’ comfort and permeability to oxygen would likely be preserved.

By this time, I was madly curious as to what these contact lenses might look like and so I found this image, accompanying the researchers’ paper,  showing what looks like a standard contact lens with an illustration of how the artist imagines the diamonds and medications are functioning at the nanoscale,

nanodiamonds

[downloaded from http://pubs.acs.org/doi/abs/10.1021/nn5002968]

Here’s a link to and a citation for the paper,

Diamond Nanogel-Embedded Contact Lenses Mediate Lysozyme-Dependent Therapeutic Release by Ho-Joong Kim, Kangyi Zhang, Laura Moore, and Dean Ho. ACS Nano, Article ASAP DOI: 10.1021/nn5002968 Publication Date (Web): February 8, 2014

Copyright © 2014 American Chemical Society

This paper is behind a paywall.

Nanodiamond grow-ops possible now nanodiamonds can be made in ambient conditions

Living in a area where marijuana grow-ops are a serious issue and something to be considered when you buy your condo, house, etc. (dangerous people showing up at odd times and structural issues are amongst two of the most feared problems), an Oct. 22, 2013 news item on Azonano featuring nanodiamonds grown at almost room-level temperatures caught my attention,

Instead of having to use tons of crushing force and volcanic heat to forge diamonds, researchers at Case Western Reserve University [Case] have developed a way to cheaply make nanodiamonds on a lab bench at atmospheric pressure and near room temperature.

The nanodiamonds are formed directly from a gas and require no surface to grow on.

The discovery holds promise for many uses in technology and industry, such as coating plastics with ultrafine diamond powder and making flexible electronics, implants, drug-delivery devices and more products that take advantage of diamond’s exceptional properties.

Their investigation is published today in the scientific journal Nature Communications. The findings build on a tradition of diamond research at Case Western Reserve.

The Oct. 21, 2013 Case University press release (also on EurekAlert), which originated the news item, explaining why this discovery is so exciting and describing the technique for creating nanodiamonds without “crushing force and volcanic heat” in more detail,

Beyond its applications, the discovery may offer some insight into our universe: an explanation of how nanodiamonds seen in space and found in meteorites may be formed.

“This is not a complex process: ethanol vapor at room temperature and pressure is converted to diamond,” said Mohan Sankaran, associate professor of chemical engineering at Case Western Reserve and leader of the project. “We flow the gas through a plasma, add hydrogen and out come diamond nanoparticles. We can put this together and make them in almost any lab.”

The process for making these small “forever stones” won’t melt plastic so it is well suited for certain high-tech applications. Diamond, renowned for being hard, has excellent optical properties and the highest velocity of sound and thermal conductivity of any material.

Unlike the other form of carbon, graphite, diamond is a semiconductor, similar to silicon, which is the dominant material in the electronics industry, and gallium arsenide, which is used in lasers and other optical devices.

While the process is simple, finding the right concentrations and flows—what the researchers call the “sweet spot”—took time.

The other researchers involved were postdoctoral researcher Ajay Kumar, PhD student Pin Ann Lin, and undergraduate student Albert Xue, of Case Western Reserve; and physics professor Yoke Khin Yap and graduate student Boyi Hao, of Michigan Technological University.

Sankaran and John Angus, professor emeritus of chemical engineering, came up with the idea of growing nanodiamonds with no heat or pressure about eight years ago. Angus’ research in the 1960s and 1970s led him and others to devise a way to grow diamond films at low pressure and high temperature, a process known as chemical vapor deposition that is now used to make coatings on computer disks and razor blades. Sankaran’s specialty, meanwhile, is making nanoparticles using cool microplasmas.

It usually requires high pressures and high temperatures to convert graphite to diamond or a combination of hydrogen gas and a heated substrate to grow diamond rather than graphite.

“But at the nanoscale, surface energy makes diamond more stable than graphite,” Sankaran explained. “We thought if we could nucleate carbon clusters in the gas phase that were less than 5 nanometers, they would be diamond instead of graphite even at normal pressure and temperature.”

After several ups and downs with the effort, the process came together when Kumar joined Sankaran’s lab. The engineers produced diamond much like they’d produce carbon soot.

They first create a plasma, which is a state of matter similar to a gas but a portion is becoming charged, or ionized. A spark is an example of a plasma, but it’s hot and uncontrollable.

To get to cooler and safer temperatures, they ionized argon gas as it was pumped out of a tube a hair-width in diameter, creating a microplasma. They pumped ethanol—the source of carbon—through the microplasma, where, similar to burning a fuel, carbon breaks free from other molecules in the gas, and yields particles of 2 to 3 nanometers, small enough that they turn into diamond.

In less than a microsecond, they add hydrogen. The element removes carbon that hasn’t turned to diamond while simultaneously stabilizing the diamond particle surface.

The diamond formed is not the large perfect crystals used to make jewelry, but is a powder of diamond particles. Sankaran and Kumar are now consistently making high-quality diamonds averaging 2 nanometers in diameter.

The researchers spent about a year of testing to verify they were producing diamonds and that the process could be replicated, Kumar said. The team did different tests themselves and brought in Yap’s lab to analyze the nanoparticles by Raman spectroscopy.

Currently, nanodiamonds are made by detonating an explosive in a reactor vessel to provide heat and pressure. The diamond particles must then be removed and purified from contaminating elements massed around them. The process is quick and cheap but the nanodiamonds aggregate and are of varying size and purity.

The new research offers promising implications. Nanodiamonds, for instance, are being tested to carry drugs to tumors. Because diamond is not recognized as an invader by the immune system, it does not evoke resistance, the main reason why chemotherapy fails.

Sankaran said his nanodiamonds may offer an alternative to diamonds made by detonation methods because they are purer and smaller.

The group’s process produces three kinds of diamonds: about half are cubic, the same structure as gem diamonds, a small percentage are a form suspected of having hydrogen trapped inside and about half are lonsdaleite, a hexagonal form found in interstellar dust but rarely found on Earth.

A recent paper in the journal Physical Review Letters suggests that when interstellar dust collides, such high pressure is involved that the graphitic carbon turns into londsdaleite nanodiamonds.

Sankaran and Kumar contend that an alternative with no high pressure requirement, such as their method, should be considered, too.

“Maybe we’re making diamond in the way diamond is sometimes made in outer space,” Sankaran proposed. “Ethanol and plasmas exist in outer space, and our nanodiamonds are similar in size and structure to those found in space.”

The group is now investigating whether it can fine-tune the process to control which form of diamond is made, analyzing the structures and determining if each has different properties. Lonsdaleite, for instance, is harder than cubic diamond.

The researchers have made a kind of nanodiamond spray paint. “We can do this in a single step, by spraying the nanodiamonds as they are produced out of the plasma and purified with hydrogen, to coat a surface,” Kumar said.

“Will they be able to scale up? That’s always a crap shoot,” Angus said. “But I think it can be done, and at very high rates and cheaply. Ultimately, it may take some years to get there, but there is no theoretical reason it can’t be done.”

Here’s an image from the researchers illustrating the technique,

Caption: (Clockwise) Microplasma dissociates ethanol vapor, carbon particles are collected and dispersed in solution, and electron microscope image reveals nanosized diamond particles. Credit: Case Western Reserve University

Caption: (Clockwise) Microplasma dissociates ethanol vapor, carbon particles are collected and dispersed in solution, and electron microscope image reveals nanosized diamond particles.
Credit: Case Western Reserve University

Here’s a link to and a citation for the research paper,

Formation of nanodiamonds at near-ambient conditions via microplasma dissociation of ethanol vapour by Ajay Kumar, Pin Ann Lin, Albert Xue, Boyi Hao, Yoke Khin Yap, & R. Mohan Sankaran. Nature Communications 4, Article number: 2618 doi:10.1038/ncomms3618  Published 21 October 2013

This article is behind a paywall,

Nanodiamonds detect the iron in your blood

Too little iron in the blood can lead to anemia and too much can signal problems with the immune system; German researchers have devised a promising new technique for detecting the amount of iron in the blood according to an Oct. 2, 2013 news item on ScienceDaily,

Lack of iron — caused by malnutrition — can lead to anemia while an increased level of iron may signal the presence of an acute inflammatory response. Therefore, the blood iron level is an important medical diagnostic agent. Researchers at Ulm University [Germany], led by experimental physicist Fedor Jelezko, theoretical physicist Martin Plenio and chemist Tanja Weil, have developed a novel biosensor for determination of iron content that is based on nanodiamonds.

Here’s an image of microscopic diamonds before they’ve been ground down to the nanoscale,

(Photo: Fedor Jelezko): Microscope picture of small diamonds, 100 microns in diameter. Specific lattice defects do not only impart colour on the diamonds but also provide the basis for the magnetic field sensor. In their experiments the team at Ulm ground down these diamonds to a size of 20 nanometers (as a comparison, a human hair has a diameter of 70 microns and is therefore 3000 times thicker than the nanodiamonds).

(Photo: Fedor Jelezko): Microscope picture of small diamonds, 100 microns in diameter. Specific lattice defects do not only impart colour on the diamonds but also provide the basis for the magnetic field sensor. In their experiments the team at Ulm ground down these diamonds to a size of 20 nanometers (as a comparison, a human hair has a diameter of 70 microns and is therefore 3000 times thicker than the nanodiamonds).

The Oct. 2, 2013 University of Ulm news release (on the Alpha Galileo Foundation website,) which originated the news item, describes the problem the scientists were addressing and their solution,

“Standard blood tests do not capture — as one might expect — free iron ions in the blood, because free iron is toxic and is therefore hardly detectable in blood,” explains Professor Tanja Weil, director of the Institute for Organic Chemistry III, University of Ulm. These methods are based on certain proteins instead that are responsible for the storage and transport of iron. One of these proteins is Ferritin that can contain up to 4,500 magnetic iron ions. Most standard tests are based on immunological techniques and estimate the iron concentration indirectly based on different markers. Results from different tests may however lead to inconsistent results in some clinical situations.

The Ulm scientists have developed a completely new approach to detect Ferritin. This required a combination of several new ideas. First, each ferritin-bound iron atom generates a magnetic field but as there are only 4,500 of them, the total magnetic field they generate is very small indeed and therefore hard to measure. This indeed, posed the second challenge for the team: to develop a method that is sufficiently sensitive to detect such weak magnetic fields. This they achieved by making use of a completely new, innovative technology based on tiny artificial diamonds of nanometer size. Crucially these diamonds are not perfect —colorless and transparent — but contain lattice defects which are optically active and thus provide the color of diamonds.

“These color centers allow us to measure the orientation of electron spins in external fields and thus measure their strength” explains Professor Fedor Jelezko, director of the Ulm Institute of Quantum Optics. Thirdly, the team had to find a way to adsorb ferritin on the surface of the diamond. “This we achieved with the help of electrostatic interactions between the tiny diamond particles and ferritin proteins,” adds Weil. Finally, “Theoretical modeling was essential to ensure that the signal measured is in fact consistent with the presence of ferritin and thus to validate the method,” states Martin Plenio, director of the Institute for Theoretical Physics. Future plans of the Ulm team include the precise determination of the number of ferritin proteins and the average iron load of individual proteins.

As the news release notes, this research is part of a larger project,

The demonstration of this innovative method, reported in Nano Letters [journal], represents a first step towards the goals of their recently awarded BioQ Synergy Grant. [10.3 million Euro which the scientists were awarded last December 2012 by the European Research Council] The focus of this project is the exploration of quantum properties in biology and the creation of self-organized diamond structures.

“Diamond sensors can thus be applied in biology and medicine,” say the Ulm scientists. But their new invention has its limits “. Whether the children have actually eaten their spinach cannot be detected with the diamond sensor, that’s still the prerogative of parents “, confesses quantum physicist Plenio

Here’s a link to and a citation for the paper,

Detection of a Few Metallo-Protein Molecules Using Color Centers in Nanodiamonds by A. Ermakova, G. Pramanik, J.-M. Cai, G. Algara-Siller,  U. Kaiser, T. Weil, Y.-K. Tzeng, H. C. Chang, L. P. McGuinness, M. B. Plenio, B. Naydenov, and F. Jelezko. Nano Lett., 2013, 13 (7), pp 3305–3309 DOI: 10.1021/nl4015233 Publication Date (Web): June 5, 2013
Copyright © 2013 American Chemical Society

This paper is behind a paywall.

Diamonds in your teeth—for health reasons

Scientists at the University of California at Los Angeles (UCLA) in collaboration with their colleagues at the NanoCarbon Research Institute (Japan) are investigating the possibility of using nanodiamonds to promote bone growth that supports dental implants. From the Sept.18, 2013 news item on ScienceDaily,

UCLA researchers have discovered that diamonds on a much, much smaller scale than those used in jewelry could be used to promote bone growth and the durability of dental implants.

Nanodiamonds, which are created as byproducts of conventional mining and refining operations, are approximately four to five nanometers in diameter and are shaped like tiny soccer balls. Scientists from the UCLA School of Dentistry, the UCLA Department of Bioengineering and Northwestern University, along with collaborators at the NanoCarbon Research Institute in Japan, may have found a way to use them to improve bone growth and combat osteonecrosis, a potentially debilitating disease in which bones break down due to reduced blood flow.

The Sept. 17,2013 UCLA news release by Brianna Deane (also on EurekAlert), which originated the news item, describes how osteonecrosis affects bones and the impact that this new technique using nanodiamonds could have on applications for regenerative medicine (Note: A link has been removed),

When osteonecrosis affects the jaw, it can prevent people from eating and speaking; when it occurs near joints, it can restrict or preclude movement. Bone loss also occurs next to implants such as prosthetic joints or teeth, which leads to the implants becoming loose — or failing.
Implant failures necessitate additional procedures, which can be painful and expensive, and can jeopardize the function the patient had gained with an implant. These challenges are exacerbated when the disease occurs in the mouth, where there is a limited supply of local bone that can be used to secure the prosthetic tooth, a key consideration for both functional and aesthetic reasons.
….
During bone repair operations, which are typically costly and time-consuming, doctors insert a sponge through invasive surgery to locally administer proteins that promote bone growth, such as bone morphogenic protein.
Ho’s team discovered that using nanodiamonds to deliver these proteins has the potential to be more effective than the conventional approaches. The study found that nanodiamonds, which are invisible to the human eye, bind rapidly to both bone morphogenetic protein  and fibroblast growth factor, demonstrating that the proteins can be simultaneously delivered using one vehicle. The unique surface of the diamonds allows the proteins to be delivered more slowly, which may allow the affected area to be treated for a longer period of time. Furthermore, the nanodiamonds can be administered non-invasively, such as by an injection or an oral rinse.
“We’ve conducted several comprehensive studies, in both cells and animal models, looking at the safety of the nanodiamond particles,” said Laura Moore, the first author of the study and an M.D.-Ph.D. student at Northwestern University under the mentorship of Dr. Ho. “Initial studies indicate that they are well tolerated, which further increases their potential in dental and bone repair applications.”
“Nanodiamonds are versatile platforms,” said Ho, who is also professor of bioengineering and a member of the Jonsson Comprehensive Cancer Center and the California NanoSystems Institute. “Because they are useful for delivering such a broad range of therapies, nanodiamonds have the potential to impact several other facets of oral, maxillofacial and orthopedic surgery, as well as regenerative medicine.”
Ho’s team previously showed that nanodiamonds in preclinical models were effective at treating multiple forms of cancer. Because osteonecrosis can be a side effect of chemotherapy, the group decided to examine whether nanodiamonds might help treat the bone loss as well. Results from the new study could open the door for this versatile material to be used to address multiple challenges in drug delivery, regenerative medicine and other fields.

Here’s a citation for and a link to the researchers’ published paper,

Multi-protein Delivery by Nanodiamonds Promotes Bone Formation by L. Moore, M. Gatica, H. Kim, E. Osawa, & D. Ho. Published online before print September 17, 2013, doi: 10.1177/0022034513504952 JDR September 17, 2013 0022034513504952

This paper is behind a paywall.