Abstract
Biological reactions of nano/micro materials are discussed. Nanomaterials are biointeractive in the sense that their size and existence themselves possess the nature to induce the bioreaction to cells and tissue. They are also bioreactive, since they induce the intrinsic functions of biological organism in a generalized sense of both merit (bioactive) and demerit (toxic) for human beings. The bilateral nature of the potentiality for both high functional performance (nanotechnology) and unintentionally occurring biohazard (nanotoxicology) is the essential properties of nano/micro materials.
