3.2.2. Shape

Shape is a physicochemical property that influences the toxicity of materials [60]. NPs have different shapes and structures such as tubes, fibers, spheres, and planes. Therefore, it may also influence their endocytosis process, internalization, bio-distribution, and elimination. For example, spherical nanoparticles of similar size have been found to be easier and faster internalized by endocytosis than rod-shaped nanoparticles, which is explained by a greater membrane wrapping time required for the elongated particles. In addition, the spherical ones are relatively less toxic [21].
