Table 2.

Veteran-relevant NP characteristics, Industrial Associations and/or Properties

Expected NP detection profile	Shape and size	Expected cellular/anatomical location and properties in vitro and in vivo
Elements from fuel combustion (gasoline, diesel, alternative mixed biofuels) and industrial sources (e-waste, lubricating oils) [275–282]: Fe, Pb, Ni, Cu, Cd, Hg, Al, Bismuth (Bi), Titanium (Ti)	Shape and size determine NP toxicity and capacity to reach target cells	Mitochondria, Golgi apparatus, lysosomes, phagosomes, and nuclei [221]
		Need to define localization of NPs in the neurovascular unit, including the BBB at endothelial level (integrity of tight junctions) [221, 289]
Technology-critical elements [283]:Gallium (Ga), Germanium (Ge), Indium (In), Tellurium (Te), Niobium (Nb), Tantalum (Ta), Thallium (Tl)
Platinum Group Elements: Platinum (Pt), Palladium (Pd), Rhodium (Rh), Osmium (Os), Iridium (Ir), Ruthenium (Ru)
Rare Earth Elements:Yttrium (Y), Lanthanum (La), Cerium (Ce), Praseodymium (Pr), Neodymium (Nd), Samarium (Sm), Europium (Eu), Gadolinium (Gd), Terbium (Tb), Dysprosium (Dy), Holmium (Ho), Erbium (Er), Ytterbium (Yb), Lutetium (Lu) [205, 282, 284–287]	Coexistence of multiple metal NPs alter the original toxicity of individual NP [285, 288]
Detection of metalloid, Si [290], which may be of relevance in the veterans from the Gulf Wars where desert dust (e.g. SiO2) and particulate matter are prevalent [291]	Si NPs 7 + nm evoke oxidative stress and mitochondrial dysfunction [292, 293]	Within neurons, microglia, oligodendrocytes, astrocytes. Greater vulnerability of astrocytes expected [294]
		Subcellular accumulation in: Mitochondria, axons [295] and Autophagosomes [221, 296]
Detection of Ti nanorods (versus spherical shape) to determine its industrial origin	Ti nanorods are associated with e-waste, while spherical Ti NPs are associated with food sources [297]	Storage in autophagosomes [221]
		Membrane damage, cell cycle interference, reactive oxygen species formation [296]