NanoSphere - Friend or Foe

Penny Bonda, FASID, LEED Fellow, HBN Board Member | July 06, 2011 | Materials

n the mysterious world of nanotechnology, it's hard to know if this emerging science is the best thing since the invention of the Dustbuster, or a health scourge.

What's a nano? Think small, very, very small, a billionth of a meter small. Comparing a nano to a meter is like comparing a marble to the Earth.

Though tiny, nanotechnology makes big promises, from keeping our clothes clean to curing cancer. So it was with great excitement that Designtex recently announced the addition of Schoeller Technology's NanoSphere to its repertoire of textile finishes, as a replacement for highly toxic perfluorocarbon stain and water repellants. "The nanotechnology-based textile impregnation features a high level of water and stain resistance... and is bluesign-certified, a multiple-attribute certification confirming that the highest human and environmental health criteria are met." Also referenced is "innovative C6 chemistry."

It is difficult for laymen like me to determine whether the treatment is safe. I was intrigued, especially because of my high regard for Designtex and its environmental commitment, but I had never heard of bluesign or C6 chemistry and went searching for more information. The Hohenstein Research Institute, an internationally recognized textile research, testing and certification body, provides some assurance. The Institute tested the biological safety of NanoSphere for possible biological activity (cytotoxicity and genotoxicity and HET-CAM[1]) and confirms that the new formulation passed these tests with excellent ratings.

However, questions remain about the safety of nanotechnology itself, and governments and industry have yet to establish what testing protocols are necessary to declare nanotechnology to be safe. Carol Derby, the Director of Environmental Strategy for Designtex, admitted to her own ambivalence. "We would like to fully embrace the Precautionary Principle," she stated, "but given the industry's demand for stain resistance, we've adopted what we believe to be the best available technology. We've confronted the problem of fluorinated compounds by switching from C8 to NanoSphere and C6 chemistry."

Designtex's goal, Carol reiterated, is to continuously evolve to better solutions. "It's difficult to satisfy all demands but our interest is to embrace the best available technology and to engage in an open, clear and understandable dialogue."

We really can't expect more than that. But when I sought the opinion of one of the most highly regarded experts in materials chemistry, Healthy Building Network's Tom Lent, who had, in fact, already looked into NanoSphere, his response was not encouraging: "There were too many ambiguities in their disclosure and in how bluesign operates to confidently recommend it."

NanoSphere, Tom reports, will not share information about what kind of nanoparticles they are using. They could be any of the common ones or ones that have not been studied. Though little scientific research is available about C6 chemistry, the elimination of PFOS and PFOA fluorochemicals does, however, appear to be an improvement over C8 fluorochemistry, NanoSphere's original formulation. Additional information is included in their FAQ publication.

Tom gives better marks to bluesign but not an outright endorsement. Complimentary of its full life cycle process and public release of its list of over 600 substances that have the potential to affect consumer safety, he expresses concerns about the ambiguity of the certification's standards and lack of disclosure of how a specific product attains bluesign. "In the end it is not possible to know what standards a bluesign certified product actually has met."

Tom's bottom line: "Nanotechnology may offer great promise for solving many performance challenges without the excessive use of chemicals, but may do it at a cost of yet new human health hazards. The technology is still in its infancy, with major questions outstanding about how these microscopic scale materials may interact with and affect our bodies."


[1] Cytotoxicity is the quality of being toxic to cell health. It is typically measured by treating cells in culture and observing how many of the cells survive. Genotoxicity is the quality of being damaging to a cell's genetic material or causing cancerous tumor growth and also measured by observing cells in culture. HET-CAM stands for Hen's Egg Test Chorioallantoic Membrane - a test using study of reaction of a hen's egg that is used to assess potential eye irritation.