New technology makes textiles permanently germ-free; targets health care-associated infections

A University of Georgia researcher has invented a new technology that can inexpensively render medical linens and clothing, face masks, paper towels -- and yes, even diapers, intimate apparel and athletic wear, including smelly socks -- permanently germ-free.

The simple and inexpensive anti-microbial technology works on natural and synthetic materials. The technology can be applied during the manufacturing process or at home, and it doesn't come out in the wash. Unlike other anti-microbial technologies, repeated applications are unnecessary to maintain effectiveness.

"The spread of pathogens on textiles and plastics is a growing concern, especially in healthcare facilities and hotels, which are ideal environments for the proliferation and spread of very harmful microorganisms, but also in the home," said Jason Locklin, the inventor, who is an assistant professor of chemistry in the Franklin College of Arts and Sciences and on the Faculty of Engineering.

The anti-microbial treatment invented by Locklin, which is available for licensing from the University of Georgia Research Foundation, Inc., effectively kills a wide spectrum of bacteria, yeasts and molds that can cause disease, break down fabrics, create stains and produce odors.

According to the Centers for Disease Control and Prevention, approximately one of every 20 hospitalized patients will contract a healthcare-associated infection. Lab coats, scrub suits, uniforms, gowns, gloves and linens are known to harbor the microbes that cause patient infections.

Consumers' concern about harmful microbes has spurred the market for clothing, undergarments, footwear and home textiles with antimicrobial products. But to be practical, both commercial and consumer anti-microbial products must be inexpensive and lasting.

"Similar technologies are limited by cost of materials, use of noxious chemicals in the application or loss of effectiveness after a few washings," said Gennaro Gama, UGARF senior technology manager. "Locklin's technology uses ingeniously simple, inexpensive and scalable chemistry."

Gama said the technology is simple to apply in the manufacturing of fibers, fabrics, filters and plastics. It also can bestow antimicrobial properties on finished products, such as athletic wear and shoes, and textiles for the bedroom, bathroom and kitchen.

"The advantage of UGARF's technology over competing methods," said Gama, "is that the permanent antimicrobial can be applied to a product at any point of the manufacture-sale-use continuum. In contrast, competing technologies require blending of the antimicrobial in the manufacturing process."

"In addition," said Gama, "If for some reason the antimicrobial layer is removed from an article—through abrasion, for example—it can be reapplied by simple spraying."

Other markets for the anti-microbial technology include military apparel and gear, food packaging, plastic furniture, pool toys, medical and dental instrumentation, bandages and plastic items.

Locklin said the antimicrobial was tested against many of the pathogens common in healthcare settings, including staph, strep, E. coli, pseudomonas and acetinobacter. After just a single application, no bacterial growth was observed on the textile samples added to the culture—even after 24 hours at 37 degrees Celsius.

Moreover, in testing, the treatment remained fully active after multiple hot water laundry cycles, demonstrating the antibacterial does not leach out from the textiles even under harsh conditions. "Leaching could hinder the applicability of this technology in certain industrial segments, such as food packaging, toys, IV bags and tubing, for example," said Gama.

Thin films of the new technology also can be used to change other surface properties of both cellulose- and polymer-based materials. "It can change a material's optical properties—color, reflectance, absorbance and iridescence—and make it repel liquids, all without changing other properties of the material," said Gama.

More information: A paper on the new technology was published by Locklin and colleagues online June 21 in ACS Applied Materials & Interfaces, a peer-reviewed journal of the American Chemical Society.

Provided by University of Georgia (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

A flash of insight: Chemist uses lasers to see proteins at work

Binghamton University researcher Christof Grewer thinks he has an important brain transport protein -- glutamate transporter -- figured out. And he's using a novel approach to spy on them by taking aim with lasers.

Grewer, a biophysical chemist, studies glutamate transport proteins, miniscule components of our brains that move glutamate among cells. Glutamate, an important molecule in cellular metabolism, is also a neurotransmitter. He explains his research on these tiny proteins in the brain using an analogy: imagine never having seen a car before and trying to determine what makes the vehicle run.

"We would be interested in seeing what happens when the car is moving, and we'd take pictures of that," he says. "We'd see the pistons moving, and that would be the beginning of understanding."

Scientists know the transport proteins are important, and they know they move glutamate in and out of cells through a sort of door in the cell wall, known as a glutamate transporter. But exactly how the proteins trigger those doors in the cell wall, and what makes them move glutamate to the inside or outside of a cell, is unknown.

Learning how those triggers function could have major implications for human health. For example, during a stroke, when blood and oxygen to the brain are restricted, brain cells release glutamate into the space surrounding them. That starts a toxic chain that can kill brain cells and harm certain brain functions. Knowing how the glutamate molecules are transported through cell walls could one day lead to drugs that help or halt the transport.

Grewer -- one of perhaps two dozen researchers in the world who work on this problem -- switches analogies as he continues describing the way these proteins move.

"Think about people being transported in an elevator in a tall building," he says. "So in order for that to work, the door of the elevator has to open, and then the person has to step into the elevator. And then the elevator brings you to a higher floor, and then the door has to open, and the person has to walk out."

In this case, glutamate molecules are the people. The elevator cars are the glutamate transporters. And the electricity and wires that move elevator doors are -- well, that's what he's trying to figure out. Grewer's brainstorm was to create a method that uses lasers to trigger the transports' action. By controlling when the movement happens, he can document it. It all goes back to his analogy of photographing a car's pistons. Taking snapshots may illuminate how the transporters and glutamate molecules work together.

Grewer stumbled onto the glutamate transporters. When he was a graduate student in physical chemistry at Johann Wolfgang Goethe-University in Frankfurt, Germany, his research focused on chemistry and light. His introduction to biochemistry -- and to glutamate receptors -- came during a post-doctoral fellowship at Cornell University.

"We were trying to activate these receptors on a very fast time scale," he says. "It's not that easy to do."

His background in chemistry and physics brought fresh insight to the lab. What if, he thought, a flash of light could help trigger the transport process? By timing the reactions, the researchers could better capture what happens during the glutamate transfer.

"They were so interesting to me that I just had to stay with them," Grewer says of glutamate transporters. "I thought, that is just the most amazing thing to study."

Most biochemical research on the brain focuses on possible cures and many researchers are experimenting with known drugs to judge their effect on brain function.

In most proteins, and in biology, researchers know what the genetic code and the DNA look like. The number of proteins in the body is also a known factor. But what's not unclear is how these proteins function. And that's where Grewer's work comes in. He has become a pioneer in the usage of lasers, which although used on other types of proteins, has not been used before in this area of study.

Story Source:

The above story is reprinted (with editorial adaptations) from materials provided by Binghamton University, via EurekAlert!, a service of AAAS.

Determining pollution level of a medium without wasting tools, time or solvents possible

 Polycyclic aromatic hydrocarbons (PAH) are organic compounds that can be highly contaminant. They are found, amongst other places, in soils occupied by metallurgical or pharmaceutical industries and in waters polluted by ships' fuel. Chemist Dani Zuazagoitia has proposed simple techniques for analysing the impact of PAHs on a number of media, based on headspace solid phase microextraction (HS-SPME). He drew up the methodology, prepared it for the pertinent circumstances and applied it in the Basque province of Gipuzkoa.

Zuazagoitia defended the thesis at the University of the Basque Country(UPV/EHU), with the title Fase solidoko mikroerauzketan oinarritutako metodoen garapena hidrokarburo aromatiko poliziklikoen determinaziorako. Aplikazioa eta ebaluazioa ingurumen laginetan (Development of SPMEs for determining PAHs. Application and evaluation in environmental samples).

Zuazagoitia has published a number of articles on his research, the latest being in the journal Soil & Sediment Contamination, and entitled "Evaluation of soil contamination by polycyclic aromatic hydrocarbons in Gipuzkoa (Northern Spain)".

Extraction without touching the sample

The HS-SPME procedure for the analysis of samples is a screening method; these analyses provide a rapid response (positive/negative) without wasting tools, time or solvents. With this procedure in concrete, a needle is inserted into the sample container top. This needle contains a fibre that has to be taken out of it on insertion, so that the substance to be analysed is absorbed from the headspace. This space is that between the sample and the cap and information can be obtained from there only in the case of volatile compounds such as PAHs. The procedure of extraction from the headspace enables conserving the fibre in optimum conditions. If it is inserted directly into the sample it can be spoilt due to the large molecules, but using HS-SPME, non-volatile and large molecule interference is avoided.

After extraction desorption should be proceeded with, in order to free the gases absorbed by the fibre and thus separate the substances. Zuazagoitia opted for gas chromatography, by which the components can be separated with notable volatility at temperatures less than 350-400 degrees. Subsequently, the components were quantified using an FIDionisation detector.

Optimisation of three procedures

For his thesis Zuazagoitia developed methods which, based on HS-SPME, determined various small and medium molecular weight PAHs simultaneously, considering the diversity of conditions that these methods have to comply with, depending on the matrix to analyse (water, earth, sediments, and so on). Likewise, given the numerous variables that condition the process, an experimental design that optimised the response of the method was opted for. Using the Statistica® programme, it is not necessary to carry out trials with each variable in order to ascertain their ups and downs beforehand.

Zuazagoitia stated that, effectively, there exist rapid and simple methods and that can be undertaken with any laboratory analytical tools. Other characteristics of these methods involve having a rapid response (positive/negative) objective and being environmentally friendly, on not using organic solvents. The three procedures optimised in the thesis (water, earth, sediments) comply with these features.

In San Sebastián, Bergara and Pasaia

The researcher also took on the task of putting into practice methods for studying the pollution of water, earth and sediments in Gipuzkoa. According to the samples analysed, the concentrations of PAHs in the sea and river water in the territory are not relevant. However, there is a high level of contamination in leached waters, meaning that there is a high concentration of PAHs in soil these originate from. With the soil samples, Zuazagoitia detected high levels of pollution in two zones of San Sebastian (the capital city of Gipuzkoa): in an area where a gas factory used to be located (in Morlans, Amara); and in a store for timber that was treated with creosote, a toxic substance (in Oriamendi). Finally, as regards sediments, PAHs were found in all the locations analysed and especially in the towns of Bergara (river Deba) and Pasaia (river Oiartzun).

Story Source:

The above story is reprinted (with editorial adaptations ) from materials provided by Elhuyar Fundazioa.