The Nanomaterial Registry: facilitating the sharing and analysis of data in the diverse nanomaterial community

Figures & data

Table 1 Descriptors of the Nanomaterial Registry minimal information about nanomaterials (MIAN)’s physicochemical characterization (PCC)

PCC	Descriptor used in the Nanomaterial Registry
Composition	Chemical information and crystal structure of the nanomaterial
Size*	The physical dimensions of a particle. For spherical particles, it is their diameter. For irregularly shaped particles, it is the diameter of the equivalent sphere that has the same volume as a particle. Also includes physical state of the sample
Size distribution	A list of values or a mathematical function that defines the relative amounts of particles present, sorted according to size – modality, peak magnitude, minimum, and maximum are included
Shape*	A geometric description of the extremities of a nanomaterial (eg, 1-D, 2-D, 3-D) along with the rigidity of its spatial arrangement, as represented in its external surface
Surface area*	The quantity of accessible surface of a nanomaterial expressed as a mass-specific surface area or as a volume-specific surface area where the total area quantity has been normalized either to the sample’s mass or to a volume
Surface chemistry	The chemical nature of the outermost layer of a nanomaterial
Surface charge	The electric charge present at the surface of the nanomaterial
Purity*	Amount of the intended substance within a manufactured material – also includes identity and amount of any contaminants
Aggregation/agglomeration state	The extent to which a group of particles, affected by attractive forces, forms groups or clusters
Solubility*	The degree to which a material can be dissolved in another material so that a single homogeneous, temporarily stable phase results. Expressed as the categorization of a material as hydrophilic or lipophilic as well as P value and D value
Stability	The measure of a system is in its lowest energy state or chemical equilibrium with its environment
Surface reactivity	Includes chemical affinities and speeds of reactions

Notes: Those PCCs marked with an asterisk were described based on the International Organization for Standardization’s (ISO) descriptions. Divergence from any standard descriptions occurred based on the scope of data curated into the Registry.

Table 2 Minimal information curate for each instance of characterization (IOC) category

Instance of characterization	Minimal information curated
As synthesized	• Manufacturer or laboratory name
	• Product name
	• Lot number
	• General synthesis description
	• DOI citation of synthetic procedure
As received	• Manufacturer or laboratory name
	• Product name
	• Lot number
As processed	• Processing details (ex aerosolized, suspended, dried, milled, heated, etc)

Abbreviation: DOI, digital object identifier.

Figure 1 Nanomaterial Registry compliance medals in decreasing order of compliance score range: gold, silver, bronze, and merit.

Table 3 Three examples of reported data from a size characterization along with the respective calculated compliance scores and levels

Size characterizations	1	2	3
Curated data	Mean Diameter = 65 nm	Mean hydrodynamic diameter = 65 nm by Dynamic Light Scattering	Mean hydrodynamic diameter, intensity weighted = 65 nm ± 4 nm by Dynamic Light Scattering Protocol: ASTM E2490-09 Instrument: Malvern ZetaSizer nano ZS ✓ph of suspension = 8.1 ✓temperature of suspension = 25°C ✓solvent/medium type = phosphate buffered saline
Compliance score	25/91 = 27.47%	51/91 = 56.04%	74/91 = 81.32%
Compliance level	Bronze	Silver	Gold

Notes: The difference for a size characterization between a bronze level and silver level could be in the reporting of the technique used, while to reach a gold level, more details on the instrumentation and protocol would be needed.

Abbreviation: ASTM, American Society for Testing and Materials.

Figure 2 Process by which growth is expected for the Nanomaterial Registry (NR).

Abbreviation: PCC, physicochemical characterization.