A capsule for removing radioactive contamination from milk, fruit juices, other beverages

In a presentation at the 243rd National Meeting & Exposition of the American Chemical Society (ACS) they said the technology could be used on a large scale by food processors or packaged into a small capsule that consumers at the home-kitchen level could pop into beverage containers to make them safe for consumption.

"We repurposed and repackaged for radioactive decontamination of water and beverages a tried-and-true process that originally was developed to mine the oceans for uranium and remove uranium and heavy metals from heavily contaminated water," said Allen Apblett, Ph.D., who led the research team. "The accident at the Fukushima nuclear plant in Japan and ongoing concerns about possible terrorist use of nuclear materials that may contaminate food and water led us to shift the focus of this technology."

The technology also can remove arsenic, lead, cadmium and other heavy metals from water and fruit juices, Apblett said, adding that higher-than-expected levels of some of those metals have been reported in the past in certain juices. He is with Oklahoma State University in Stillwater.

Nanoparticles composed of metal oxides, various metals combined with oxygen, are the key ingredients in the process. The particles, so small that hundreds would fit on the period at the end of this sentence, react with radioactive materials and other unwanted substances and pull them out of solution. The particles can absorb all 15 of the so-called "actinide" chemical elements on the periodic table of the elements, as well as non-actinide radioactive metals (e.g., strontium), lead, arsenic and other non-radioactive elements.

The actinides all are radioactive metals, and they include some of the most dangerous substances associated with nuclear weapons and commercial nuclear power plant accidents like Fukushima. Among them are plutonium, actinium, curium and uranium.

In the simplest packaging of the technology, the metal-oxide nanoparticles would be packed inside a capsule similar to a medicine capsule, and then stirred around in a container of contaminated water or fruit juice. Radioactive metals would exit the liquid and concentrate inside the capsule. The capsule would be removed, leaving the beverage safe for consumption. In laboratory tests, it reduced the concentrations of these metals to levels that could not be detected, Apblett noted.

The technology is moving toward commercialization, with the first uses probably in purifying calcium dietary supplements to remove any traces of lead, cadmium and radiostrontium. Apblett said the capsule version could have appeal beyond protection against terrorist attacks or nuclear accidents, among consumers in areas with heavy metals in their water or food supplies, for instance.

More information: Abstract
Nuclear accidents such as the ones at the Fukushima nuclear plant in Japan and at Chernobyl along with the legacy of past use and testing of nuclear weapons have highlighted the need for technologies to decontaminate food and water that contain radionuclides. The potential for future nuclear wars and even the contamination of food and water by spent uranium penetrators further delineate the need for technologies to protect animals and the public. We have developed technologies based on nanoparticulate metal oxides that have very high capacity for radionuclides. For example, they can be used to remove radiostrontium from milk. The use of suitably-derivitized nanoporous silicas for this purpose will also be discussed.

Provided by American Chemical Society (news : web)

Capsule for removing radioactive contamination from milk, fruit juices, other beverages

Amid concerns about possible terrorist attacks with nuclear materials, and fresh memories of environmental contamination from the 2011 Fukushima Daiichi nuclear disaster in Japan, scientists have described the development of a capsule that can be dropped into water, milk, fruit juices and other foods to remove more than a dozen radioactive substances.

In a presentation at the 243rd National Meeting & Exposition of the American Chemical Society (ACS), they said the technology could be used on a large scale by food processors or packaged into a small capsule that consumers at the home-kitchen level could pop into beverage containers to make them safe for consumption.

"We repurposed and repackaged for radioactive decontamination of water and beverages a tried-and-true process that originally was developed to mine the oceans for uranium and remove uranium and heavy metals from heavily contaminated water," said Allen Apblett, Ph.D., who led the research team. "The accident at the Fukushima nuclear plant in Japan and ongoing concerns about possible terrorist use of nuclear materials that may contaminate food and water led us to shift the focus of this technology."

The technology also can remove arsenic, lead, cadmium and other heavy metals from water and fruit juices, Apblett said, adding that higher-than-expected levels of some of those metals have been reported in the past in certain juices. He is with Oklahoma State University in Stillwater.

Nanoparticles composed of metal oxides, various metals combined with oxygen, are the key ingredients in the process. The particles, so small that hundreds would fit on the period at the end of this sentence, react with radioactive materials and other unwanted substances and pull them out of solution. The particles can absorb all 15 of the so-called "actinide" chemical elements on the periodic table of the elements, as well as non-actinide radioactive metals (e.g., strontium), lead, arsenic and other non-radioactive elements.

The actinides all are radioactive metals, and they include some of the most dangerous substances associated with nuclear weapons and commercial nuclear power plant accidents like Fukushima. Among them are plutonium, actinium, curium and uranium.

In the simplest packaging of the technology, the metal-oxide nanoparticles would be packed inside a capsule similar to a medicine capsule, and then stirred around in a container of contaminated water or fruit juice. Radioactive metals would exit the liquid and concentrate inside the capsule. The capsule would be removed, leaving the beverage safe for consumption. In laboratory tests, it reduced the concentrations of these metals to levels that could not be detected, Apblett noted.

The technology is moving toward commercialization, with the first uses probably in purifying calcium dietary supplements to remove any traces of lead, cadmium and radiostrontium. Apblett said the capsule version could have appeal beyond protection against terrorist attacks or nuclear accidents, among consumers in areas with heavy metals in their water or food supplies, for instance.

The scientists acknowledged funding from the Oklahoma Economic Development Generating Excellence Program.

Story Source:

The above story is reprinted from materials provided by American Chemical Society (ACS), via Newswise.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Unique gel capsule structure enables co-delivery of different types of drugs

Researchers at the Georgia Institute of Technology have designed a multiple-compartment gel capsule that could be used to simultaneously deliver drugs of different types. The researchers used a simple "one-pot" method to prepare the hydrogel capsules, which measure less than one micron.

The capsule's structure -- hollow except for polymer chains tethered to the interior of the shell -- provides spatially-segregated compartments that make it a good candidate for multi-drug encapsulation and release strategies. The microcapsule could be used to simultaneously deliver distinct drugs by filling the core of the capsule with hydrophilic drugs and trapping hydrophobic drugs within nanoparticles assembled from the polymer chains.

"We have demonstrated that we can make a fairly complex multi-component delivery vehicle using a relatively straightforward and scalable synthesis," said L. Andrew Lyon, a professor in the School of Chemistry and Biochemistry at Georgia Tech. "Additional research will need to be conducted to determine how they would best be loaded, delivered and triggered to release the drugs."

 

Lyon and Xiaobo Hu, a former visiting scholar at Georgia Tech, created the microcapsules. As a graduate student at the Research Institute of Materials Science at the South China University of Technology, Hu is co-advised by Lyon and Zhen Tong of the South China University of Technology. Funding for this research was provided to Hu by the China Scholarship Council.

The researchers began the two-step, one-pot synthesis procedure by forming core particles from a temperature-sensitive polymer called poly(N-isopropylacrylamide). To create a dissolvable core, they formed polymer chains from the particles without a cross-linking agent. This resulted in an aggregated collection of polymer chains with temperature-dependent stability.

"The polymer comprising the core particles is known for undergoing chain transfer reactions that add cross-linking points without the presence of a cross-linking agent, so we initiated the polymerization using a redox method with ammonium persulfate and N,N,N',N'-tetramethylethylenediamine. This ensured those side chain transfer reactions did not occur, which allowed us to create a truly dissolvable core," explained Lyon.

For the second step in the procedure, Lyon and Hu added a cross-linking agent to a polymer called poly(N-isopropylmethacrylamide) to create a shell around the aggregated polymer chains. The researchers conducted this step under conditions that would allow any core-associated polymer chains that interacted with the shell during synthesis to undergo chain transfer and become grafted to the interior of the shell.

Cooling the microcapsule exploited the temperature-sensitivities of the polymers. The shell swelled with water and expanded to its stable size, while the free-floating polymer chains in the center of the capsule diffused out of the core, leaving behind an empty space. Any chains that stuck to the shell during its synthesis remained. Because the chains control the interaction between the particles they store and their surroundings, the tethered chains can act as hydrophobic drug carriers.

Compared to delivering a single drug, co-delivery of multiple drugs has several potential advantages, including synergistic effects, suppressed drug resistance and the ability to tune the relative dosage of various drugs. The future optimization of these microcapsules may allow simultaneous delivery of distinct classes of drugs for the treatment of diseases like cancer, which is often treated using combination chemotherapy.

Provided by Georgia Institute of Technology (news : web)

Unique gel capsule structure enables co-delivery of different types of drugs

Researchers at the Georgia Institute of Technology have designed a multiple-compartment gel capsule that could be used to simultaneously deliver drugs of different types. The researchers used a simple "one-pot" method to prepare the hydrogel capsules, which measure less than one micron.

The capsule's structure -- hollow except for polymer chains tethered to the interior of the shell -- provides spatially-segregated compartments that make it a good candidate for multi-drug encapsulation and release strategies. The microcapsule could be used to simultaneously deliver distinct drugs by filling the core of the capsule with hydrophilic drugs and trapping hydrophobic drugs within nanoparticles assembled from the polymer chains.

"We have demonstrated that we can make a fairly complex multi-component delivery vehicle using a relatively straightforward and scalable synthesis," said L. Andrew Lyon, a professor in the School of Chemistry and Biochemistry at Georgia Tech. "Additional research will need to be conducted to determine how they would best be loaded, delivered and triggered to release the drugs."

Details of the microcapsule synthesis procedure were published online on July 5, 2011 in the journal Macromolecular Rapid Communications.

Lyon and Xiaobo Hu, a former visiting scholar at Georgia Tech, created the microcapsules. As a graduate student at the Research Institute of Materials Science at the South China University of Technology, Hu is co-advised by Lyon and Zhen Tong of the South China University of Technology. Funding for this research was provided to Hu by the China Scholarship Council.

The researchers began the two-step, one-pot synthesis procedure by forming core particles from a temperature-sensitive polymer called poly(N-isopropylacrylamide). To create a dissolvable core, they formed polymer chains from the particles without a cross-linking agent. This resulted in an aggregated collection of polymer chains with temperature-dependent stability.

"The polymer comprising the core particles is known for undergoing chain transfer reactions that add cross-linking points without the presence of a cross-linking agent, so we initiated the polymerization using a redox method with ammonium persulfate and N,N,N',N'-tetramethylethylenediamine. This ensured those side chain transfer reactions did not occur, which allowed us to create a truly dissolvable core," explained Lyon.

For the second step in the procedure, Lyon and Hu added a cross-linking agent to a polymer called poly(N-isopropylmethacrylamide) to create a shell around the aggregated polymer chains. The researchers conducted this step under conditions that would allow any core-associated polymer chains that interacted with the shell during synthesis to undergo chain transfer and become grafted to the interior of the shell.

Cooling the microcapsule exploited the temperature-sensitivities of the polymers. The shell swelled with water and expanded to its stable size, while the free-floating polymer chains in the center of the capsule diffused out of the core, leaving behind an empty space. Any chains that stuck to the shell during its synthesis remained. Because the chains control the interaction between the particles they store and their surroundings, the tethered chains can act as hydrophobic drug carriers.

Compared to delivering a single drug, co-delivery of multiple drugs has several potential advantages, including synergistic effects, suppressed drug resistance and the ability to tune the relative dosage of various drugs. The future optimization of these microcapsules may allow simultaneous delivery of distinct classes of drugs for the treatment of diseases like cancer, which is often treated using combination chemotherapy.

Story Source:

The above story is reprinted (with editorial adaptations) from materials provided by Georgia Institute of Technology Research News. The original article was written by Abby Robinson.

Journal Reference:

Xiaobo Hu, Zhen Tong, L. Andrew Lyon. One-Pot Synthesis of Microcapsules with Nanoscale Inclusions. Macromolecular Rapid Communications, 2011; DOI: 10.1002/marc.201100338