In a recent issue of Standardization News, I read an interesting article that discussed the development of ASTM nanotechnology standards. Elsewhere in the publication, the president of ASTM International referenced “the spirit of cooperative antagonism” that comes from a cross-section of experts and dedicated professionals who often engage in rigorous debate and contention because they will likely be impacted by the final standards. I simply want to tell you who these people are and thank them for the hard work that they do.
Firstly, Nanotechnology is a discipline that covers areas ranging from biotechnology, medicine, and energy to computer science and consumer cosmetics. The discipline generally considers materials within the range of 1nm to 100nm and it is critically important to understand these materials and develop standards for them while also ensuring safety since they can often cross through barriers such as skin, cell membranes, and lab gloves.
These nanomaterials are often in a size range that people are not accustomed to measuring and making measurements on them is often full of sample preparation and dispersion issues. Providing clear methods so that measurements can be made in repeatable ways is a true challenge and the best methods often vary based on the type of nanomaterial being investigated.
Interlaboratory studies are used by ASTM International Committee E56 to address these sample preparation and measurement issues and this Committee on Nanotechnology is composed of “the cooperative antagonists” charged with developing new standards of measurement for nanomaterials. The use of interlaboratory studies allow the ASTM committee to have confidence in test methods by establishing a level of precision in the methods so they can then define and develop test methods and reference materials amenable to nanomaterial characterization and manufacture.
An example of a recently published ASTM standard is the “Standard Guide for Measurement of Electrophoretic Mobility and Zeta Potential of Nanosized Biological Materials” (E2865–12). This describes how the diffusion barrier method can be used to measure the mobility and zeta potential in systems containing biological material such as proteins, DNA, liposomes and other similar organic materials, that possess particle sizes in the nanometer scale (<100 nm). The diffusion barrier method only requires 20µl of sample, which is directly injected into a Disposable Folded Capillary Cell and run on a Zetasizer Nano instrument that is capable of measuring zeta potential (such as the Zetasizer Nano-ZS).
It is not uncommon for those of us involved in measuring nanoscale materials to be asked, “What is the best way to prepare and measure my nanoparticle?” There is no simple answer to this question and the best answers might be as numerous as the number of identified nanomaterials themselves. This is an area of science that is in great need of standards and reference materials and I simply want to thank ASTM International Committee E56 for the hard work they do in providing us guidance and bringing us closer to some solid answers.