CNSI Nanotoxicology Research & Training Program

The Nanotoxicology Research and Training Program

Characterization and Ranking of Nanomaterial Physical-Chemical Properties

Back to Research Themes page.

In addition to the combinatorial library of engineered nanomaterials, the following natural nanoparticles will be studied. First, we intend to assess their physicochemical characteristics, transport and fate, and biological interactions for direct comparison with engineered nanomaterials. Next, we will determine how selected natural materials interact with engineered nanomaterials to alter physicochemical properties, transport, fate, and toxicity. The proposed research on the interactions between natural and engineered nanomaterials in different aqueous matrices may to lead to novel approaches for tailoring the stability of engineered nanoparticles to facilitate or hinder transport, reactivity, and uptake as desired. These solutions will inform and direct nanoparticle synthesis and modification strategies to enable safety-by-design and enhance environment protection and remediation strategies.

Table 1. Selection of natural nanomaterials

Category/Class	Composition	Size/Mw	Supplier	Product No.
Aerosol nanoparticles
Carbonaceous	Carbon nanopowder	< 50 nm	Sigma	633100
Silicic	Silica nanopowder	10-20 nm	Sigma	637238
Silicic	Porous silica nanopowder	5-15 nm	Sigma	637246
Aquatic colloidal materials
Metal oxides	Alumina nanoparticles	< 50 nm	Sigma	544833
Metal oxides	Alumina nanowiskers	2-4 nm × 2800 nm	Sigma	551643
Metal oxides	Iron (II,III) oxides	< 50 nm	Sigma	637106
Metal oxides	Calcium oxide	50-160	Sigma	634182
Metal oxides	Magnesium oxide	25-50	Sigma	549649
Clays	Halloysite nanoparticles	~30 nm × 0.5-4 μm	Sigma	685445
Clays	Bentonite nanoparticles	~1-2000 nm	Sigma	682659
Biopolymers	Alginic acid	~20-80 kDa	Sigma	A7003
Biopolymers	γ-cyclodextrin	~1300 Da	Fluka	28708
Biopolymers	Phosphatidylinositol	~700-1,000 Da	BioChemika	79403
Humics	soil-derived humic acid	~500-10,000 Da	IHSS	1S102H
Humics	soil-derived fulvic acid	~500-10,000 Da	IHSS	2S102F
Humics	aquatic humic acid	~500-10,000 Da	IHSS	2S101H
Humics	aquatic fulvic acid	~500-10,000 Da	IHSS	1S101F

UC Nanotox researchers have already characterized physical-chemical properties of a wide array of aquatic organic matter, colloids, and microorganisms. For example, we already have characterized aquatic NOM, algal biopolymers, proteins, oxide and clay particles, yeast cells, and bacteria by light scattering, particle micro-electrophoresis, direct titration, scanning electron microscopy, atomic force microscopy, and multiple probe liquid contact angle analyses. Representative surface charge and energy data are presented in the tables below as an example of one of our approaches for ranking engineered and natural NM properties. The techniques utilized here are being extended to characterize engineered nanomaterials in various dry and dispersed states. Basic characterization of engineered nanomaterials are performed in isolation and in the presence of natural nanoparticles, organics, and bacteria. The latter studies will provide an understanding of the impacts of water quality and natural nanomaterials on the physicochemical properties of reference nanomaterials synthesized for the CEIN.

Table 2. Surface energetic ranking of natural and engineered materials

Table 3. Surface charge ranking of natural and engineered materials