Tag Archives: nanoparticle

Test tube oils.

Nanoparticle treatment developed to scrub water clean of oil pollution

New research from the Rice University may hold the key to scrubbing water clean of oily pollutants.

Test tube oils.

The team developed nanoparticles that draw in the bulk of the oil and are then attracted to the magnet, as demonstrated here.
Image credits Jeff Fitlow / Rice University.

Water and oil don’t mix; except when they do. While the two fluids tend to separate readily, they’re able to mix just well enough to bind together. We call the resulting mixture an ’emulsion’. Not very dangerous in your kitchen — mayonnaise, for example, is an emulsion — but the phenomenon can cause problems in production water from oil wells. ‘Produced water’ comes from oil wells along with crude.

Looking for a way to scrub water clean in such cases, researchers from the Rice University have developed a nanoparticle-based solution that can remove 99% of the emulsified oil left over from oil wells.

The solution relies on magnetic nanoparticles that can attract oil droplets suspended in production water. The approach can scrub even those drops of oils that existing processes simply can’t remove.

Crude mixtures

Produced water is often laced with surfactants and other chemical compounds. These compounds are pumped into a crude oil reservoir to reduce the crude’s viscosity and help with extraction.

Now, believe it or not, you have some surfactants (surface acting substances) in your house; at least a bottle or a block of the stuff. You call it ‘soap‘. Soap helps you get clean by forcing water and fats (such as oils) to mix. One end of the soap molecule is hydrophilic (it ‘likes’ water) while the other end is hydrophobic (it ‘fears’ water). The hydrophilic end sports a water-soluble molecule that binds to water molecules, while the other end boasts a molecule that’s soluble in fats. Once each end has tied to the compounds of their affection, the soap molecule acts as a chain linking fat to water.

Sodium Stearate.

The chemical structure of sodium stearate, the main ingredient in soaps. The O-Na bond forms the hydrophilic ‘head’, while the tail represents the hydrophobic area.
Image credits Smokefoot / Wikimedia.

In an oil well, surfactants force the crude to form stable emulsions with water. Because this emulsion is less viscous than the crude alone, it’s more easily pumped by derricks up to the surface. Most of the crude can be separated and then extracted from such emulsions. A fraction of about 5% is never or almost never recovered, and remains tied to the water.

“Injected chemicals and natural surfactants in crude oil can oftentimes chemically stabilize the oil-water interface, leading to small droplets of oil in water which are challenging to break up,” said Sibani Lisa Biswal, paper co-author and an associate professor of chemical and biomolecular engineering and of materials science and nanoengineering.

The paper combines Biswal’s expertise with magnetic nanoparticles with lead author Qing Wang’s experience with amines. The amines’ role is to guide the nanoparticles to oil droplets — amines carry a positive charge and oil is negatively-charged, so they attract. Magnets are then used to draw all the nanoparticles out of the solution.

They tested the nanoparticles in emulsions produced in the lab using either model oil or crude oil. In both cases, the team dropped their compound into the emulsions, shook them by hand or machine, and had oil-nanoparticle bonds form within minutes. Some of the oil floated to the top by this stage. The test tubes were then placed atop a magnet which drew the rest to the bottom — leaving clean water in between.

The research is remarkable as nanoparticles tend to aggregate (clump together) in high-salinity environments — such as those found in reservoir fluids — but the ones developed by the team remain stable in produced water. Furthermore, these nanoparticles can be treated with a solvent to recover the oil; they can be re-used after cleaning. So far, the team proved that the nanoparticles can go through six charge-discharge cycles while remaining effective. However, they suspect that the compound can remain effective for many more cycles.

Biswal’s team is now designing a flow-through reactor to scrub large quantities of produced water and automatically recycle the nanoparticles.

Household oil pollution is a huge issue nowadays, one that the team’s efforts may help address. Oil scrubbing may help protect the waterways for communities that can’t or don’t treat wastewater, or create an extra precaution for communities that do.

A component from scorpion and honeybee venom stops cancer growth

Scorpion toxins may soon be useful as anticancer drugs. Credit: Courtesy of Dipanjan Pan

The difference between a poison and a cure is the dosage – and this could be very well said about this approach. Bio-engineers report that peptides in some venoms bind to cancer cells and block tumor growth and spread and could be effectively used to fight cancer – the only problem is they might also harm healthy cells.

Bioengineer Dipanjan Pan and coworkers at the University of Illinois, Urbana-Champaign, are now using polymeric nanoparticles to deliver venom toxin directly to cancer cells. The problem is limiting the effect it has to the cancer cells, and avoiding any damage to healthy cells. The researchers inserted a derivative of TsAP-1, a toxin peptide from scorpion venom, into specific spherical nanoparticles, constructing what they call NanoVenim. When they tested it on cancerous tissue in the lab, NanoVenim was 10 times more effective at killing the cancerous cells and spreading their growth than the toxin alone.

They researched a similar procedure with a nanoparticle-encapsulated version of melittin (a toxin from honeybee venom), and the results were even more promising. The toxin had potency against cancer cells, but on the upside, it didn’t do any damage at all to healthy cells.

“We have known for some time that venom toxins have anticancer potential, if only we could deliver them safely and selectively to tumors,” said David Oupicky, codirector of the Center for Drug Delivery & Nanomedicine at the University of Nebraska Medical Center.

However, the trick here is nanotechnology; even a simple nanotechnological delivery method can work wonders (such as increasing the efficiency 10 times). Pan’s idea with scorpion venom injected through nanotechnology  “is new, and the method of incorporation into nanoparticles is fairly new as well,” he added. But it’s perhaps the honeybee venom which shows the most promise:

 “[That it] works against cancer cells but appears not to damage erythrocytes is an important step toward practical application. It will be very interesting to see how the particles behave in vivo.”

Now, having successfully tested the idea on lab tissue, the next step is to conduct animal tests. Pan’s team founded a start-up, VitruVian Biotech which will conduct testings on rats and pigs. However, with so promising results, he believes that they could start human clinical trials in three to five years.

small-intestine

Nanoparticle pill delivers insulin orally with 11-fold efficiency

Drug delivery encapsulated in tiny nanoparticles are thoroughly studied with great interest because they offer the chance to deliver treatments more efficiently. That’s not all though – with nanoparticle pills you can selectively target key areas and deliver drugs which otherwise wouldn’t be possible without using invasive methods. Take diabetes  for instance – patients need to take shots of insulin on a regular basis and this is the only way the drug can be delivered effectively so far. A team of researchers at MIT have demonstrated, however, insulin absorption in the bloodstream of mice through nanoparticle pill oral ingestion. The findings could pave the way for other kinds of drugs becoming orally ingestistable, which are currently delivered only through invasive methods, like those targeting cancer.

“If you were a patient and you had a choice, there’s just no question: Patients would always prefer drugs they can take orally,” says Robert Langer, the David H. Koch Institute Professor at MIT, a member of MIT’s Koch Institute for Integrative Cancer Research, and an author of the Science Translational Medicine paper.

Of course, this is not the first research we’ve reported that discusses oral nanoparticle delivery. The key finding from MIT lies in the way the drugs bind to the intestinal inner wall. Previously, it was shown that when feeding on their mother’s milk, babies absorb antibodies contained in the milk to boost their own immune defense. These antibodies are absorbed through  cell surface receptor called the FcR, which allows them to enter the blood stream.

The nano-pills of the future

Exploiting this biophysical processes, the researchers coated their nanoparticles containing the drug payload (insulin) with Fc proteins which attach themselves to the FcR receptors. Once attached to the receptors, the particles bring along the bio-compatible nanoparticles along with them.

After administering the nanoparticles oral to mice, the researchers measured 11-fold efficiency of insulin absorption in the bloodstream than nanoparticles devoid of the Fc protein coating.

“It illustrates a very general concept where we can use these receptors to traffic nanoparticles that could contain pretty much anything. Any molecule that has difficulty crossing the barrier could be loaded in the nanoparticle and trafficked across,” says  Rohit Karnik, an MIT associate professor of mechanical engineering.

small-intestine

image source: diet777.com

That’s very interesting, but it gets even more promising when you consider nanoparticle drug delivery can be used for treating all kinds of diseases that currently rely on invasive operations; i.e. cancer. The are numerous challenges to orally ingested nanoparticles though. Like a biological wall, the intestinal lining typically keeps drugs from reaching tumors via the blood stream.

“The key challenge is how to make a nanoparticle get through this barrier of cells. Whenever cells want to form a barrier, they make these attachments from cell to cell, analogous to a brick wall where the bricks are the cells and the mortar is the attachments, and nothing can penetrate that wall,” said  Omid Farokhzad, director of the Laboratory of Nanomedicine and Biomaterials at BWH.

The present research illustrates that intestinal cells can be breached, proving oral nanoparticle delivery can be attained. Further animal tests and experiments using other types of drugs are planned.

“If you can penetrate the mucosa in the intestine, maybe next you can penetrate the mucosa in the lungs, maybe the blood-brain barrier, maybe the placental barrier,” said Farokhzad.

A new fluorescent glucose-amine probe can make identification of cancer cells (green) using two-photon microscopy easier and safer (credit: Guan Wang/National University of Singapore)

Safe bioimaging uses fluorescent nanoparticles to 3-D render cancer cells. Cancels the need for biopsy

Detecting the extent of soft-tissue diseases, such as breast cancer, typically requires invasive medical procedures, like a biopsy. A team of researchers at the A*STAR Institute of Materials Research and Engineering has developed a new self-assembled nanoparticle which acts as a safe fluorescent probe, used to generate 3-D pictures of cancer cell structures in living tissue.

 

A new fluorescent glucose-amine probe can make identification of cancer cells (green) using two-photon microscopy easier and safer (credit: Guan Wang/National University of Singapore)

A new fluorescent glucose-amine probe can make identification of cancer cells (green) using two-photon microscopy easier and safer (credit: Guan Wang/National University of Singapore)

Two-photon microscopy (TPM) uses non-linear absorption of two photons to induce fluorescence that is confined to a very small region. A laser beam scans laterally across the sample to generate 2D fluorescence images from an extremely thin optical section within the sample. This optical section can be varied in depth, building up a stack of images to produce a 3D rendering of the sample.

However, Two-photon microscopy comes at a great disadvantage when used to scan for disease tissue in human patients. The substance used as light-emitting fluorescent probes are usually quantum dots made from nanoscale aggregates of elements such as cadmium and selenium. However these elements are toxic to biological organisms and thus restrict their application.

Bin Liu and colleagues have managed to find a safe alternative by devising a self-assembled nanoparticle capable of absorbing sufficient amounts of laser light to initiate fluorescence imagining. Typically such tiny organic molecules are unable to absorb enough laser light, however the scientists synthesized their material into a star-shaped compound, called dendrimer. This geometry induces much larger cross sections that can absorb two-photons better than isolated fluorescent dyes. The  star-shaped dendrimer is biocompatible with cell tissue.

For their experiment, the researchers targeted the surfaces of a breast cancer cell line known as MCF-7.  They found that the dendritic dye self-assembled into dispersed nanoparticles when submerged in water; in this particular form the  two-photon-absorption cross sections are increased, thus providing a high yield of laser-induced fluorescence. Subsequent TPM imaging revealed a bright fluorescence localized inside the cancer cell cytoplasma as seen in the image captioned in this article.

Their work, reported in the Chemistry European Journal, suggests that bioimaging using this technique is both effective and safe. Quite possibly, if extended to real applications, this technique might revolutionize the field and turn highly invasive procedures obsolete.

 

IBM nanoparticle destroys drug resistant bacteria

I had no idea IBM was doing this kind of thing too, but I recently found out that they developed a technology that could revolutionize the treatment of drug resistant bacteria. A whole team of engineers and researchers headed by Dr. James Hedrick at IBM Inc. has worked on this technology, which relies on a nanoparticle that destroys the membrane walls of certain drug-resistant bacteria strains and then harmlessly leaves the cell without leaving any trace of its passing.

The whole system is extremely ingenious: it uses biodegradable plastic to create electrically charged nanoparticles that attract the bacteria’s oppositely charged membrane, and destroys it, thus destroying the bacteria alltogether. Since the molecules used for it are organic, the body is able to dispose of them easily, thus removing the chance of any unwanted side effects.

The system has yet to be tested on humans but IBM stated it is negotiating human trials with some pharmaceutical companies, though they haven’t divulged which ones; however, Dr. Hedrick called the results “extraordinarily promising at this stage”, which can only be a good sign. If it turns out that it can be used on humans too, this technology has the ability to save millions and millions of lives, by treating and curing stubborn bacterias which have become highly resistant to traditional treatment, a problem our society has to face more and more.