Nanotechnology is the production of materials at atomic and molecular level and is expected
to open some new avenues to fight and prevent diseases. It leads to improvement in biology,
biotechnology, medicine and healthcare by uncovering the structure and function of
biosystems at the nanoscale. The size of nanomaterials is similar to that of the most
biological molecules and structures; therefore, nanomaterials can be useful for both in vivo
and in vitro biomedical research and applications. Due to the expected growth in this field
and new materials being employed, there is a call for safety and exposure risks. Hence, for
improved characterization and reliable toxicity assessments, toxicological studies of
nanosystems are growing at exponential rates annually. For these reasons, screening assays
are needed to assess the chemical and physical properties of nanomaterials. Lacking the
proper interactions of nanostructures with the biological systems, it is unclear whether the
exposure could produce harmful biological responses. Deploying these materials in vivo has
even more challenges. So, in vitro methods are commonly used for toxicity assessment of
nanoparticles. Nanoparticle risk assessment can be done with existing cytotoxicity methods,
or with the development of new test systems with new standards for a general in vitro toxicity
testing of nanoparticles. An altogether different approach is required for nanoparticle
characterization and for bioassays, in order to validate their properties in physiology. The
present review focuses on the various in vitro methods of nanotoxicity assessment and the
advantages offered by them. The article also sheds some light on the applications of these
methods.
