Definition and Characteristics
Nanomaterials are defined by the ASTM as a material with two or three dimensions between 1 to 100 nm. They can be composed of many different base materials (carbon, silicon, and metals such as gold, cadmium, and selenium). They can also have different shapes: such as nanotubes, nanowires, crystalline structures such as quantum dots, and fullerenes. Nanomaterials often exhibit very different properties from their respective bulk materials: greater strength, conductivity, and fluorescence, among other properties.
The toxicity of most nanomaterials is currently unknown. Preliminary toxicity testing has indicated that some nanoparticles may be more toxic than the corresponding micron sized particle because of their greater surface area and reactivity. Nano-sized titanium dioxide produces 40 fold more lung inflammation than micron-sized particles. In preliminary tests, carbon nanotubes have produced lung inflammation and fibrosis similar to crystalline quartz and asbestos. Nanoparticles are similar in size to viruses and are easily taken up by the body’s cells, translocate around the body, and can possibly pass into the brain and through the skin.
Training on Nanomaterial Health and Safety
EHS has developed a web-based training on the health and safety of nanomaterials, which includes information on toxicity of different types of nanomaterials and laboratory practices to prevent exposures.
Please go the following link for a self-paced course: [link to Articulate course]
A pdf of resources can be found here: [link to pdf]
A powerpoint of the slides can be found here [link to pptx]
If you have any questions after reviewing these materials, please contact the EHS Office at firstname.lastname@example.org or 452-3477. An EHS Officer can also visit your lab for a review of your procedures.
Safe Work Practices and Proper Disposal:
The MIT EHS Office considers nanoparticles that have the potential for release into the air to be handled as particularly hazardous substance because their toxicity is, for the most part, unknown and early studies have been suggestive of toxic effects. In the future, many types of nanoparticles may turn out to be of limited toxicity but precaution must be used until we know more. The following best practices should be followed:
- Work with nanoparticles that may release particles should be conducted in enclosures, fume hood, glove boxes, and other vented enclosures.
- All work should be done with gloves (at a minimum disposable nitrile gloves)
- Currently, nanoparticles and solutions containing them are being disposed of as hazardous waste. Label all containers of nanomaterials (including waste) with the designation “nano”.
Detailed information on best laboratory practices for working with nanomaterials can be found at: University_Best_Practices.pdf
A checklist for developing your laboratory Standard Operating Procedure for nanomaterials work can be found at: Checklist_Developing_Nanomaterials_SOP.pdf
A review of the toxicity of some major categories of nanomaterials is at: Nanomaterial toxicity
This article also lists good reference sources for researchers to consult to keep up with toxicity information on their materials as it develops.
Please call the EHS Office at 617-253-0344 for exposure evaluation of experimental setups and additional information.
Nanomaterials can be handled in fume hoods, biosafety cabinets and other exhausted enclosures. However these hoods often have high air velocities that can be disruptive to handling dry, lightweight nanomaterials. Laboratories in Mechanical Engineering and Center for Materials Science and Engineering have purchased a specially designed type of enclosure for handling nanopowders. This type of enclosure differs from a traditional fume hood in that the slots for exhausted air are located above the floor of the unit. Therefore air currents do not disturb the handling of light, fluffy nanopowders or nanotubes. These units were originally developed to enclose sensitive balances but can be used either to weigh nanomaterials or manipulate samples.
Enclosures for Handling Nanomaterials : Left - Nanoenclosure, Right- Fan and HEPA Unit
Each unit is connected to a fan plus High Efficiency Particulate Air (HEPA) filter which removes nanoparticulate from the exhaust air. Because the HEPA filter only removes particulate, they cannot be used with solvents unless connected to laboratory exhaust. Researchers in Mech E and CMSE have reported that it is easier to handle carbon nanotubes and other nanopowders in these units than in traditional fume hoods. Annual testing of the HEPA filters by an outside vendor is required to be arranged by the laboratory. Please contact the EHS Office at email@example.com for the names of vendors for these enclosures and testing companies.