A breath-takingly simple test for human exposure to potentially toxic substances

 

The search for a rapid, non-invasive way to determine whether people have been exposed to potentially toxic substances in their workplaces, homes and elsewhere in the environment has led scientists to a technology that literally takes a person's breath away. Their report identifying exhaled breath as an ideal indicator of such exposure appears in ACS' Environmental Science & Technology.

Andrea M. Dietrich, Masoud Agah, and their students Heather Vereb and Bassam Alfeeli explain that scientists have known since the late 1970s that exhaled breath contains traces of any potentially toxic substances that people may have inhaled. Research has shown that those amounts are an accurate reflection of the levels that exist in a person's blood. Those advances have positioned exhaled breath as the ideal substance to use in rapid, non-invasive, simple testing for human exposure to potentially harmful substances in the air. Sampling breath is less invasive than drawing blood, more convenient than taking urine samples and "shows promise as an inexpensive method with a fast turnaround time," they state.

The article describes how advances in microelectronics have helped position breath analysis for more extensive use in the 21st century. Equipment for analyzing substances in human breath that once had to be housed in laboratories, for instance, have shrunk to hand-held size. The technology can detect minute amounts of substances in the breath and do so quickly — offering the promise of helping limit human exposure and improve health.

More information: The Possibilities Will Take Your Breath Away: Breath Analysis for Assessing Environmental Exposure, Environ. Sci. Technol., Article ASAP. DOI: 10.1021/es202041j

Abstract
Human breath is the gaseous exchange with the blood and thus contains trace organic contaminants and metabolites representative of environmental doses. Sampling and analysis of gaseous components in human breath offers a noninvasive and quick means of qualitatively and quantitatively assessing internalized doses of environmental contaminants. Although the humid and complex nature of breath is a challenge for detection of part-per-trillion to part-per-billion concentrations of environmental contaminants, recent advances in chemical analysis and instrumentation are allowing determination of environmental exposure and disease detection.

Provided by American Chemical Society (news : web)

ECHA: The Member State Committee identifies seven new Substances of Very High Concern

Seven Substances of Very High Concern (SVHCs) will soon be added to the Candidate List. During its 18th meeting, the Member State Committee also unanimously agreed on four draft decisions based on ECHA’s testing proposal examination and on five draft decisions based on compliance checks.

The seven new substances identified as SVHCs are: 2-ethoxyethylacetate, strontium chromate, 1,2-Benzenedicarboxylic acid, di-C7-11 branched and linear alkyl esters (DHNUP), hydrazine, 1-methyl-2-pyrrolidone, 1,2,3-trichloropropane, 1,2-benzenedicarboxylic acid and di-C6-8-branched alkyl esters, C7-rich (DIHP). These substances are either carcinogenic, mutagenic or reprotoxic (CMR) substances. DHNUP and DIHP will complement the Candidate List with two additional phthalates.

In addition, as a result of the procedure for identification as SVHC a new identification basis (toxic for reproduction) will be added for cobalt(II)chloride that is already on the Candidate List because of its carcinogenic hazards. No comments challenging the new identification basis were received during public consultation and thus no formal agreement of MSC was needed for this case.

The Candidate List will be updated soon as the seven new substances and the “toxic for reproduction” will be added as the basis for identification as an SVHC for cobalt (II)chloride .

View the original article here

Plastic products leach toxic substances

Many plastic products contain hazardous chemicals that can leach to the surroundings. In studies conducted at the University of Gothenburg, a third of the tested plastic products released toxic substances, including 5 out of 13 products intended for children.

"Considering how common plastic products are, how quickly the production of plastic has increased and the amount of chemicals that humans and the environment are exposed to, it is important to replace the most hazardous substances in plastic products with less hazardous alternatives," says Delilah Lithner of the Department of Plant and Environmental Sciences at the University of Gothenburg.

Plastics exist in many different chemical compositions and are widespread in the society and the environment. Global annual production of plastics has doubled over the past 15 years, to 245 million tonnes in 2008. The plastic polymers are not regarded as toxic, but there may be toxic residual chemicals, chemical additives and degradation products in the plastic products that can leach out as they are not bound to the plastic polymer. Plastics also cause many waste problems.

In her research, Lithner studied the toxicity of 83 randomly selected plastic products and synthetic textiles. The newly purchased products were leached in pure (deionised) water for 1?? days. The acute toxicity of the water was then tested using water fleas (Daphnia magna).

"A third of all the 83 plastic products and synthetic chemicals that were tested released substances that were acutely toxic to the water fleas, despite the leaching being mild. Five out of 13 products that were intended for children were toxic, for example bath toys and buoyancy aids such as inflatable armbands," says Delilah Lithner.

The products that resulted in toxic water were soft to semi-soft products made from plasticised PVC or polyurethane, as well as epoxy products and textiles made from various plastic fibres. The toxicity was mainly caused by fat-soluble organic substances.

Lithner also studied the chemicals used to make around 50 different plastic polymers and has identified the plastic polymers for which the most hazardous chemicals are used. They were then ranked on the basis of the environmental and health hazard classifications that exist for the chemicals. Examples of plastic polymers made from the most hazardous chemicals are certain polyurethanes, polyacrylonitriles, PVC, epoxy and certain styrene copolymers. The results are of great benefit for further assessing environmental and health risks associated with plastic materials.

Provided by University of Gothenburg (news : web)

Third of tested plastic products found to leach toxic substances in Swedish study

ScienceDaily (May 16, 2011) — Many plastic products contain hazardous chemicals that can leach to the surroundings. In studies conducted at the University of Gothenburg, a third of the tested plastic products released toxic substances, including 5 out of 13 products intended for children.

"Considering how common plastic products are, how quickly the production of plastic has increased and the amount of chemicals that humans and the environment are exposed to, it is important to replace the most hazardous substances in plastic products with less hazardous alternatives," says Delilah Lithner of the Department of Plant and Environmental Sciences at the University of Gothenburg.

Plastics exist in many different chemical compositions and are widespread in the society and the environment. Global annual production of plastics has doubled over the past 15 years, to 245 million tonnes in 2008. The plastic polymers are not regarded as toxic, but there may be toxic residual chemicals, chemical additives and degradation products in the plastic products that can leach out as they are not bound to the plastic polymer. Plastics also cause many waste problems.

In her research, Lithner studied the toxicity of 83 randomly selected plastic products and synthetic textiles. The newly purchased products were leached in pure (deionised) water for 1-3 days. The acute toxicity of the water was then tested using water fleas (Daphnia magna).

"A third of all the 83 plastic products and synthetic chemicals that were tested released substances that were acutely toxic to the water fleas, despite the leaching being mild. Five out of 13 products that were intended for children were toxic, for example bath toys and buoyancy aids such as inflatable armbands," says Delilah Lithner.

The products that resulted in toxic water were soft to semi-soft products made from plasticised PVC or polyurethane, as well as epoxy products and textiles made from various plastic fibres. The toxicity was mainly caused by fat-soluble organic substances.

Lithner also studied the chemicals used to make around 50 different plastic polymers and has identified the plastic polymers for which the most hazardous chemicals are used. They were then ranked on the basis of the environmental and health hazard classifications that exist for the chemicals. Examples of plastic polymers made from the most hazardous chemicals are certain polyurethanes, polyacrylonitriles, PVC, epoxy and certain styrene copolymers. The results are of great benefit for further assessing environmental and health risks associated with plastic materials.

The thesis Environmental and health hazards of chemicals in plastic polymers and products was successfully defended in public on 6th May 2011.

Story Source:

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

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

Synthetic hydrogels improve testing of active substances in 3-D cell culture

 

 

The life science company Cellendes in Germany has developed synthetic hydrogels that make it possible to culture cells in three-dimensional environments. Their invention has fundamental advantages over other hydrogels for three-dimensional cultivation, also on the market.

Many researchers culture cells in flat dishes, two-dimensional culture systems. A disadvantage is that the cells behave differently than they would in a living organism. To offer an environment that resembles the living organism better, Dr. Birgitte Angres and Dr. Helmut Wurst have developed synthetic transparent hydrogels for three-dimensional applications within their life science company Cellendes (Cell-Environment-Design).

“Compared to other hydrogels on the market ours can be much easier modified with bioactive factors such as peptides right at the bench. So customers can choose which peptides they want to include in their culture. They can either purchase them from us or have their own being synthesized. Secondly, the concentration of bioactive factors, such as peptides, in our gels can be much higher than in the competitors’ gels,” Dr. Helmut Wurst said.

The hydrogels are made in a few minutes by combining two solutions in the form of an activated polymer and a cross-linking agent. Through a chemical reaction the polymers use the agent to link themselves together and a three-dimensional network, where the average pore is about eight nanometers wide, forms. Before the linking occurs it is possible to bind biofactors to the polymer and mix in cells.

The biggest challenge, from a technical point of view, during the development of the hydrogels has been to make these components reproducible. “You can do it once and then the next time maybe a little bit different, but you want to make a reproducible quality of your different components and I think that is the biggest problem,” Wurst said.

At the moment Wurst and his colleagues are trying to make it possible to store and ship the gels at room temperature and not in refrigerated conditions, to save costs in shipping. They also want to make the gels form a little bit slower. “The gels form so fast that it is sometimes difficult to mix the two different solutions completely,” Wurst said.

Almost all of Cellendes’ customers are doing basic research within the field of the life sciences. However, their hydrogels could also be useful in the chemical industry and within drug and cosmetic development. “Efforts are made to reduce the number of experimental animal testings. In our system the cells are cultured in a more natural environment and could replace certain animal models,” Wurst said.

Within the European Commission-funded project ProNano - Promoting Technology Transfer of Nanosciences, Nanotechnologies, Materials and new Production Technologies, Cellendes researchers have been selected to receive coaching to make their results in nanotechnologies reach the market.

Source: Youris.com (news : web)