CEIN Blog

  • Improved Method to Understand if a Material is Toxic


    POST DATE: 2017-12-15 at 00:00:00

    Publication: “Semiconductor Electronic Label-Free Assay for Predictive Toxicology

    Press release: "Nanomaterial safety screening could become faster, cheaper with new laboratory test"

    Quick Summary:

    Researchers at CEIN have developed an improved test for the toxic effects of nanomaterials. This type of toxicological testing is often time- and labor-intensive, and very expensive. This new test allows researchers to prioritize the nanomaterials to fully test by rapidly identifying those that are predicted to have toxic effects.

    The Full Story:

    Whenever there is a new chemical or material that is proposed for human use, it is important to evaluate its safety. This means that a scientist needs to do a lot of experiments in the lab first to understand the behavior of the new material. Then, the scientist can introduce the material to cells that are grown in the lab to see if there are any adverse effects. Next, the scientist can use an animal model to understand if the material might have some effects in the body that are not able to be seen in cells that are grown in the laboratory. This process is not only time- and labor-intensive, it is also really expensive. There are more than 90,000 chemicals and materials that exist or are being developed, and this type of testing is important for each one. The guidelines for each of the chemicals is not always the same. For example, the way that something like table salt is evaluated will be very different than the way a new chemotherapy is evaluated. Since more people are likely to be exposed to table salt on a frequent basis, it is important that it doesn’t have any toxic effects. However, it might be ok for a new chemotherapy to have some toxic effects if it is effective at treating the cancer and extending life and quality of life for cancer patients.

    Caption: The device (on the bottom left panel “e”) is made using nanowires (on the top left panel “b”). The use of engineered nanomaterials allows the researchers to increase the sensitivity of the device compared to methods that are currently used. This technology could help researchers more quickly detect the toxic effects of various materials. Image reprinted with permission by Nature Publishing Group from Mao, Shin, Wang, Ji, Meng and Chui, Scientific Reports (2016).

    If scientists had a better way to screen a large number of materials to easily and rapidly determine if toxic effects are predicted (research of this type is called predictive toxicology). There are currently some methods that can be used to predict the safety of new compounds, but these tests are quite long, can have a high cost, and required highly trained employees to run the tests and analysis.

    Researchers improved on existing technology to develop a rapid screening method, based on a nano-scale transistor. They used this as a sensor to detect a protein called interleukin-1-beta (also called IL-1b). This is a protein that your immune system can produce in response to inflammation in your lungs. Researchers demonstrated that they were able to detect IL-1b as well as the currently used method (the expensive one that requires a skilled technician).

    Caption: Using this new technology, researchers are able to quickly scan a wide variety of different nanomaterials. The images above represent different types of nanomaterials, that differ in their chemical composition, size, and shape. Image reprinted with permission by Nature Publishing Group from Mao, Shin, Wang, Ji, Meng and Chui, Scientific Reports (2016).

    Why is this important?

    Engineered nanomaterials are being developed at a rapid pace in research laboratories, and being proposed for use in consumer products. However, their full safety profiles have not yet been determined. When a new consumer product goes on the market, it is important to consider the health and environmental impact of the product. What is the impact of manufacturing the product? What is the impact of using the product? How does the product get disposed, and what is the impact of the product on the environment after its disposal? This device can help to answer the question about the potential health effects on users in a way that is faster and more efficient than traditional methods.

  • Engineered Nanomaterials, Predictive Toxicology, and the CEIN Approach


    POST DATE: 2017-11-01 at 08:00:00

    The University of California Center for Environmental Implications of Nanotechnology (UC CEIN) was established in 2008 with the mission of studying engineered nanomaterials (ENMs, also sometimes called engineered nanoparticles). Funded by the National Science Foundation and the United States Environmental Protection Agency, UC CEIN seeks to understand the properties that make ENMs toxic, both to humans and in the environment.

    Engineered nanomaterials are a class of materials that are made in a lab to have very controlled properties. The term nano means that one dimension of the material should have a size between 1-100 nanometers in length. To put that in perspective, 5 nanometers is about how big a single molecule of insulin is, or about 40 times smaller than the smallest object we can see using a light microscope, and a sheet of paper is 100,000 nanometers thick. Some nanomaterials are naturally-occurring, like casein (a molecule in milk and cheese products) or things like sea spray (also called aerosols, that can be as small as 100 nanometers, but can also be larger). Naturally-occurring nanoparticles can have a lot of variability in their shapes and sizes. Instead, engineered nanomaterials are developed in a research lab. They have well-defined sizes and shapes (meaning that the sizes and shapes can be made so they are all the same, instead of having big differences, like what is sometimes seen in nature). Because of this, engineered nanomaterials can have very well-defined properties. 

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    Caption: The physical and chemical properties of the engineered nanomaterials (such as the chemical elements used to make the nanomaterial, the size and shape of the material, or whether the surface has apositive or negative charge) can have a big impact on the toxicity of hte material as well as how it interacts with the environment. Image reprinted with permission from Royal Society of Chemistry from Chemical Communications, Lazarovitis, Chen, Sykes, and Chan, 2015.

    It is the mission of UC CEIN to study these properties to understand how they might influence the toxicity of ENMs. In order to act as responsible stewards to the environment, it is important to identify and fundamentally understand the properties of ENMs that make them toxic. It is not only important to identify the properties that make ENMs toxic to humans—since ENMs could be used in consumer products—but also the properties that make ENMs toxic to various organisms in the environment (to make sure any waste from the production of ENMs or manufacture of products with ENMs are not harmful to the environment, and to determine if ENMs can “leak” out of consumer products when they are disposed, for example, into a landfill). 

    This area of research, determining whether a material has properties that are toxic, is called toxicology. It requires each new material generated in a lab to be fully tested. First, a series of tests are done in the research laboratory to see how the material interacts with cells and with animal models (this can be yeast or bacteria, fish or frogs, mice or rats, or other organisms to help scientists identify whether the material is toxic). Once the safety in animals has been established, the material can begin being tested in humans to further evaluate its safety. If a negative (toxic) result comes back at any point on the path of toxicology screening, the material is considered to not be safe for human use or consumption (depending on the product). As you can imagine, determining whether a new material (like a new medicine for headaches) is toxic is a very complicated, and costly, process. For each new material that is developed, the cost of full toxicological screening is prohibitive in most cases.

    Caption: The goal of UC CEIN is to identify the properties of nanomaterials that make them toxic and understand the various stages where nanomaterials could enter the environment. By examining each stage of the "life cycle" of nanoparticles, researchers can make better recommendations for lawmakers on how to regulate nanomaterials. Image source: Nano.gov, "Nanotechnology and You: Environmental, Health, and Safety Issues.

    As a part of its mission to “ensure the responsible use and safe implementation of nanotechnology in the environment”, the UC CEIN has focused on developing new methods to more quickly screen ENMs for toxic properties. This is done by taking a small number of ENMs and identifying which properties make them toxic. These properties could be things like shape, dimensions, the ability of the particle to stick to other particles or to stick to organisms, the electrical charge, and many others. By identifying these structure-activity relationships that make ENMs harmful, perhaps we can predict which ENMs are likely to be nontoxic (and those are are likely to be toxic) so that we can prioritize which ENMs get in-depth toxicological testing first. This is important for saving both time and money in the development of materials and products, and is a key tool for future research in ENMs.