Tag Archives: Janus particle

Starry gold and silica Janus particles

A Feb. 11, 2014 news item on phys.org features a joint Basque/Belgian research collaboration on a Janus-type particle useful for future biomedical applications,

Researchers from the Basque centre CIC biomaGUNE and the University of Antwerp (Belgium) have designed nanoparticles with one half formed of gold branches and the other of silicon oxide. They are a kind of Janus particle, so-called in honour of the Roman god with two faces, which could be used in phototherapy in the future to treat tumours.

The Feb. 11, 2014 Platforma SINC news release on the Alpha Galileo website, which originated the news item, elaborates on the Janus myth and on the research,

In Roman mythology, Janus was the god of gates, doors, beginnings and transitions between the past and the future. In fact, the first month of the year, January (from the Latin, ianuarĭus), bears his name. This deity was characterised by his profile of two faces, something which has inspired scientists, when naming their chemical designs with two clearly distinct components.

Now, a team of researchers from CIC biomaGUNE in San Sebastian, together with colleagues from the Belgian University of Antwerp, have created Janus particles of nanometric size. They are constituted by silicon oxide on one side and gold points on the other.

Here’s an image of the ‘starry’ particles supplied by the researchers,

Two examples of nanostars with one silicon oxide face (bluish) and another with golden branches (yellow). / Credit: Liz-Marzán et al.

Two examples of nanostars with one silicon oxide face (bluish) and another with golden branches (yellow). / Credit: Liz-Marzán et al.

The news release goes on to describe the ‘starry’ particles in more detail,

As Luis Liz-Marzán, the main author of this study published in the journal ‘Chemical Communications’, explains to SINC: “These nanostars have optical and electronic properties determined largely by their small dimensions and their morphology.”

The researchers have come up with techniques to mould the sharp gold points from nanoparticles of this metal, such that very intense electric fields can be generated on the gold points using light.

“Our research is basic science, but these fields are used in processes of ultrasensitive detection to identify negligible quantities of molecules that can be absorbed on the gold face as contaminants or biomarkers that indicate the presence of a disease,” says Liz-Marzán.

Another possible application is phototherapy, the object of which is to kill malignant cells using heat, in this case induced by lighting the gold points. The oxide face would be used to join the nanostars to specific biological receptors that would take them to the damaged cells and only to these, so that the metal part can exercise its therapeutic or diagnostic function.

These nanoparticles are produced in various stages. First, golden nanospheres are produced by the chemical reduction of a salt from the precious metal. Then, two different organic compounds are added on opposite sides of the particle in order to give them distinct affinity due to the silicon oxide. In this way, the oxide covers only one part and the other remains uncovered in order to let the golden points grow.

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

Denis Rodríguez-Fernández, Thomas Altantzis, Hamed Heidari, Sara Bals, Luis M. Liz-Marzán. “A protecting group approach toward synthesis of Au–silica Janus nanostars”. Chemical Communications 50: 79-81, 2014. DOI: 10.1039/C3CC47531J.

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I last wrote about a Janus particle in an Aug. 13, 2009 post about research at Duke University.

Norwegians hoping to recover leftover oil with nanotechnology-enabled solutions

Sabina Griffith’s Jan. 21, 2013 article for Dailyfusion.net profiles two petroleum-themed research projects funded by the Research Council of Norway,

Two new research projects are receiving funding from the Research Council of Norway to develop nanoparticles that can dislodge leftover oil that remains trapped in reservoirs after conventional recovery has been completed.

Every percentage point of enhanced oil recovery rate represents billions in revenues.

“Nanotechnology is a generic technology with the potential for a wide variety of industrial applications,” says Aase Marie Hundere, Special Adviser at the Research Council and part of the NANO2021 program secretariat. “The petroleum industry is Norway’s largest, with vast international potential. Collaboration with the PETROMAKS 2 program provides an excellent opportunity to attract projects that involve specific users from industry.”

A Jan. 17, 2014 Research Council of Norway news release by Claude R. Olsen/Else Lie. Translation: Darren McKellep/Carol B. Eckmann describes first one project and its proponents,

Plugging errant water paths with gel

One of the problems with reservoirs that have been producing petroleum for an extended period is that the water injected flushes less and less oil out. Eventually the injected water is wasted, flowing through the same water-saturated zones rather than being diverted through new areas still containing mobile oil.

SINTEF [Scandinavia’s largest independent research organization] Petroleum Research is heading a project to develop chemical systems that can seal off these zones by sending a solution of nanoparticles and polymers down into the reservoir to the areas where the operator wants to prevent water from flowing. Once they are in position the particles, together with the polymers, will form a gelatinous structure (a gel) that prevents water from flowing through.
It may take the particles weeks or months to make their way through the reservoir, so the project researchers will have to figure out how to keep the gel from forming before the particles have reached their intended destination.

Another critical point will be to discover how the particles are transported through the porous rock: Will they slip through easily to their destination or get caught up in the pore walls along the way?

Together with NTNU, the University of Kansas and a number of petroleum companies, SINTEF will investigate two alternative solutions. Both are based on silica nanoparticles whose surface has been engineered to bind polymers together and form a gel. Developed by SINTEF Materials and Chemistry, the nanoparticles are similar to those used in certain products by Norwegian paint producer Jotun and in other products.

In the first alternative, chemicals will be used to deactivate the surface of the nanoparticles – keeping them passive for weeks or even months – before being activated to bind the polymers together at their destination point.

In the second alternative, active nanoparticles will be packaged into larger nanoparticles that transport them to the point where they are to be released in order to form the gel. The smaller particles will be produced by SINTEF. The University of Kansas has developed the transport particles and is already testing them in field experiments at North American oil reservoirs.

Project manager Torleif Holt of SINTEF Petroleum Research sees great potential for the technology, if successful.

“In the course of our three-and-a-half-year project period, we hope to have learned enough to know whether this method is viable,” he explains. “We would then able to estimate the quantities of nanoparticles needed and have some idea about when this is a financially feasible option.”

Here’s an image of trapped oil, gas, and water,

Functionalised particles to speed up oil flow While the SINTEF project focuses on plugging holes, the NTNU-led project is looking to speed up the flow of oil. Much of a reservoir’s oil remains trapped in small rock pores. NTNU researchers will be customising nanoparticles that can help to dislodge this oil and dramatically increase the amount of oil that can be recovered.  One method will utilise “Janus particles”, which feature a special surface of two different hemispheres: one is hydrophilic (attracted to water), the other hydrophobic (attracted to oil). Down in the reservoir, where both oil and water are found, the nanoparticles will spin like wheels and push the oil forward. “This is an early-stage project,” says project manager Jianying He, an associate professor at the NTNU Nanomechanical Lab. “But the idea is very exciting and has major potential for raising the recovery rate of Norwegian oil.” The petroleum companies Det norske and Wintershall are signed on as partners, and project researchers will be communicating with Statoil as well. The University of Houston is the research partner. The second method involves changing the surface charge of nanoparticles to make them capable of slipping between a reservoir’s oil and rock. If development proceeds as planned, Professor He estimates that the nanoparticles will be on the market in roughly seven years. She sees two challenges to using nanoparticles for enhanced recovery: HSE and production capacity. HSE should not be problematic in this case, as studies show that silica-based particles are not hazardous to the environment. Production capacity, however, may prove to be an obstacle to large-scale utilisation of nanoparticles. Petroleum companies would need millions of tonnes of nanoparticles daily. Currently there is no facility that can produce such quantities.  [downloaded from http://www.forskningsradet.no/en/Newsarticle/Nanotechnology_to_recover_stubborn_oil/1253992231414/p117731575391]

Microscope image of reservoir rock. The rock pores (shown in blue) may contain trapped oil, gas and water. Nanoparticles can be used to recover more of the residual oil. (Photo: Ingrid Anne Munz) [downloaded from http://www.forskningsradet.no/en/Newsarticle/Nanotechnology_to_recover_stubborn_oil/1253992231414/p117731575391]

The news release then describes the other project and its proponents,

Functionalised particles to speed up oil flow

While the SINTEF project focuses on plugging holes, the NTNU [Norges teknisk-naturvitenskapelige universitet; Norwegian University of Science and Technology]-led project is looking to speed up the flow of oil. Much of a reservoir’s oil remains trapped in small rock pores. NTNU researchers will be customising nanoparticles that can help to dislodge this oil and dramatically increase the amount of oil that can be recovered.

One method will utilise “Janus particles”, which feature a special surface of two different hemispheres: one is hydrophilic (attracted to water), the other hydrophobic (attracted to oil). Down in the reservoir, where both oil and water are found, the nanoparticles will spin like wheels and push the oil forward.

“This is an early-stage project,” says project manager Jianying He, an associate professor at the NTNU Nanomechanical Lab. “But the idea is very exciting and has major potential for raising the recovery rate of Norwegian oil.”

The petroleum companies Det norske and Wintershall are signed on as partners, and project researchers will be communicating with Statoil as well. The University of Houston is the research partner.

The second method involves changing the surface charge of nanoparticles to make them capable of slipping between a reservoir’s oil and rock.

If development proceeds as planned, Professor He estimates that the nanoparticles will be on the market in roughly seven years. She sees two challenges to using nanoparticles for enhanced recovery: HSE  [health, safety, and environment?] and production capacity. HSE should not be problematic in this case, as studies show that silica-based particles are not hazardous to the environment.

Production capacity, however, may prove to be an obstacle to large-scale utilisation of nanoparticles. Petroleum companies would need millions of tonnes of nanoparticles daily. Currently there is no facility that can produce such quantities.

I had no idea Norway was so dependent on the petroleum industry. As for the nanoparticles referred to throughout the descriptions for both projects, I’d love to know more about them.

Janus particle breakthrough; science knowledge or illiteracy?

It’s a two-faced particle named after the Roman god, Janus (love the reference to Roman mythology) and complete control has been achieved. The Janus particle is made up of at least two different substances according to this 2005 news item on Phyorg.com. From the 2005 new item,

A Janus particle is composed of two fused hemispheres, each made from a different substance than the other. This means Janus particles could, for instance, carry two different and complementary medicines.

For instance, one side could hold compounds that bind to molecules specific to a certain tissue or disease, while the opposite side would carry the appropriate drug.

There are other potential applications as researchers at Duke University note in their media release posted on Phyorg.com on Aug. 12, 2009. The Duke researchers have achieved control over the particle’s movements. From the media release on Physorg.com,

Duke University engineers say they can for the first time control all the degrees of the particle’s motion, opening up broad possibilities for nanotechnology and device applications. Their unique technology should make it more likely that Janus particles can be used as the building blocks for a myriad of applications, including such new technologies as and self-propelling micromachines.

There are more details and a Janus particle video here. I did get a little confused with this description,

“Past experiments have only been able to achieve four degrees of control using a combination of magnetic and optical techniques,” said Nathan Jenness, a graduate student who completed his studies this year from Duke’s Pratt School of Engineering. He and co-author Randall Erb, also a graduate student, were first authors of a paper appearing online in the journal Advanced Materials. “We have created a novel Janus particle that can be manipulated or constrained with six degrees of freedom.”

I looked at the video where the range of motion appeared to be much broader than the 6 degrees that the researcher mentions. Perhaps the phrase “of freedom” is of more significance than I know. This brings me to Andrew Maynard’s discussion (on his blog 2020 Science) of a book on science illiteracy. Titled Unscientific Americans: How Scientific Illiteracy Threatens Our Future, the book’s authors (Chris Mooney and Sheril Kirshenbaum) caught my attention with their recent essay (based in part on their book) on Salon.com where they elucidate their position.They make a compelling argument and one I find emotionally satisfying unfortunately it’s a little problematic as Maynard points out here.

It’s more than just amusing when Maynard (a scientist by training) notes that he could be described as scientifically illiterate since there are scientific terms that he doesn’t understand and that “Math makes my head ache.” If you take the comment to its logical conclusion,you can infer that all scientists are scientifically illiterate since none of them can know everything about science. Maynard notes that he enjoyed the book but has some major issues with the term “scientific illiteracy” as promotes and “us vs them” mentality and the book’s intellectual depth. He also offers some recommendations for reading about science and society.  I do have some hesitation about one of his recommendations but more about that tomorrow.