Two-dimensional Nanomaterials (2D-Nanomaterials) constitute a large and diverse family of materials, characterized by a distinct planar morphology, unique physicochemical properties, significant electronic and thermal conductivity, as well as photoactive and catalytic features.

This chapter will focus on the biological interactions and responses to graphene, layered transition metal dichalcogenides and transition metal dioxides, as examples for 2D-Nanomaterials. These specific examples provide a mechanistic framework for understanding the physical and chemical properties responsible for the toxicity of 2D-Nanomaterials. Possible routes of exposure and potentially adverse health impacts will be discussed, followed by chemical transformation and biodegradation of these materials. Physicochemical properties related to toxicity, the mechanism of toxicity, and implications for a safer design will conclude this chapter.