Biomedical Engineering Reference
In-Depth Information
As discussed in Chapter 3, progress in developing ENMs for study was evaluated as some to little
(rated either yellow or red). In particular, little to no progress was considered to have occurred in
developing benchmark (for positive and negative controls) and reference materials for metrology. The
nanotechnology EHS-research enterprise has mostly relied on commonly available nanoparticles to
conduct most studies. These particles, typically produced to evaluate their use in specific applications or
produced as commercially available research samples, are largely categorized by core material. The vast
majority of the studies have been conducted on a relatively small number of core species, including
carbon nanomaterials (tubes, fullerenes, and graphene), metals (primarily silver and gold), metal oxides
(primarily zinc oxide, titanium dioxide, cerium oxide), and polymeric materials. There is no process to
determine which nanomaterials should have high priority for development on the basis of the needs for
mechanistic studies or investigations of materials in complex systems. To move high-priority research
toward green, additional effort and coordination are required to develop appropriate nanomaterial
libraries. Similarly, the lack of a systematic process for collecting information needed to create a picture
of nanomaterial production along the value chain limits the pace of research required to conduct risk
evaluations and the feedback needed to improve nanomaterial properties from EHS and sustainability
perspectives.
Steps to Ensure Progress Toward Providing Reference Materials
The lack of availability of ENMs for research and the limits of our knowledge of commercial
ENM production quantities and formats create a critical-path challenge in advancing nanotechnology
EHS research. Important elements for advancing the development and distribution of reference
nanomaterials for research and analytic purposes include
A mechanism to identify and set priorities among nanomaterials and libraries for development.
Developing precisely defined and characterized reference materials is expensive and time-consuming.
Sustainable approaches are needed to set priorities among materials for development and distribution to
researchers.
Material descriptors and other nomenclature to distinguish properly between different
nanomaterial samples. Appropriate and standardized material descriptors need to be adopted and used.
Without such descriptors, the specificity or precision with which nanomaterials are designed, developed,
and shared will not be sufficient, particularly for developing the knowledge commons. This is one aspect
of the ontology that needs to be developed for ENMs.
Improved synthesis and purification methods. Once nanomaterials are identified for research
purposes, the synthesis and purification methods to produce them may need to be developed. Although
some methods have been developed for synthesis of specific classes of nanomaterials, new methods need
to be developed for other nanomaterials that have been identified for development.
Collaborations among scientists who are studying mechanisms and complex systems so that
materials for these studies can be optimized. The production of a reference material or library is only the
beginning of its development. Reference nanomaterials require further optimization through collaboration
among material developers and users (for example, to optimize handling protocols or for in situ
monitoring of the nanomaterials).
Instrumentation for rapid characterization of reference materials. Although there has been
progress in developing instrumentation and protocols for characterization of pristine, synthesized
nanoparticles in the laboratory, new methods and approaches are needed to accelerate routine
characterization. For example, laboratory-scale, small-angle x-ray scattering can be used to reduce the
number of artifacts during analysis and reduce the time for characterization from hours (or days) to
minutes relative to transmission electron microscopy.
Instrumentation to characterize complex nanoscale species (that is, materials of unknown
origin, mixtures, and released materials). Each of these material classes presents challenges to
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