Assessment of Biodurability of Nanomaterials and the Surface Ligands

Biodurability of nanomaterials (NMs) through dissolution and enzymatic biodegradation or chemical disintegration is an important property that needs to be investigated for their potential to cause harm to humans and the environment. NMs may therefore be differentiated based on their biodurability between those that are amenable and those that are resistant to dissolution, biodegradation and/or disintegration. In vitro cellular and acellular as well as in vivo tests are available to assess the biodurability of NMs. With cellular and acellular in vitro tests, the dissolution of NMs is determined using static and flow-through protocols in the presence of different biological and environmental media with different pH values and chemical compositions. Examples of biological media include artificial pulmonary interstitial fluid (Gamble’s) balanced electrolyte solution (neutral) and alveolar lysosomal (ALF) (acidic) as well as gastric (acidic) and intestinal (neutral) fluids. Examples of environmental media include synthetic freshwater, sea water, estuarine water, sediments, soils and digested sludge under conditions that mimic actual environmental conditions such as presence of microbes, pH, redox potential and temperature. In vivo tests include animal inhalation and intratracheal instillation studies. 

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