For instance, it has been shown that silver nanoparticles exposed to stomach fluid undergo changes in size, shape, and composition, and the rates of these changes are dependent on particle size (see: "Changes in silver nanoparticles exposed to human synthetic stomach fluid: Effects of particle size and surface chemistry").
But this means that, if size, including the influence of agglomeration/aggregation, can change with environmental conditions, then real-time monitoring of engineered nanomaterial behavior within biological environments will be extremely difficult. Also, numerous preanalysis steps, including degradation of the food matrix and separation of the compounds of interest from background nanomaterials, are required to isolate the nanomaterial for characterization.
What approaches are currently available?
"Due to the complexity and wide chemical and physical disparity of nanomaterials at different points in time from processing to ingestion, it is likely that no single method will suffice to characterize the potential benefits or risks that these materials may present to the consumer," write the authors. "A combination of methods aimed at assessing specific questions will likely be needed to ascertain the best analytical results."
They explain that detection methods differ based on the specific questions being addressed, such as the following:
Are nanoscale materials present, or have they dispersed into their molecular components and therefore ceased to be nanomaterials?
Do the nanoscale materials have a consistent size and shape, or have they become chemically altered due to biological interaction such as aggregation/ disaggregation?
Has there been chemical transformation of some surface or core component (i.e., oxidation or reduction), or is the concentration of some component changing?
Is it necessary to ascertain the amount of nanomaterial present and where exactly the nanomaterial is located, or is it appropriate to ascertain only if it is present?
The article then goes on and details the various detection techniques currently available for various nanomaterials.
Concluding, the author team emphasizes the need for interdisciplinary collaboration in order to allow active sharing of knowledge among chemists, physicists, toxicologists, food technologists, instrument vendors, and other important stakeholders: "Moving beyond the isolation of critical information within individual knowledge domains and stakeholder groups will leverage nanotechnology and the nanoscale from an area of perceived uncertainty and debate into a rich field of potential."
Ref - © Nanowerk
