Nanoscience is generally defined as the study of matter and phenomena in the nanoscale, which is understood as the interval between 1 and 100 nanometers, that is, between 1 and 100 millionth parts of a millimeter. To this scale belong objects made up of relatively few atoms or molecules, which often behave differently to those objects that we find during our daily lives, in the macroscale. Of course, nanoscience as a field is not a separated field from other sciences but it includes the parts of others such as physics, biology, chemistry and engineering that are relevant to its own domain.
Notwithstanding this multidisciplinar base, research at the nanoscale involves new challenges that are conventionally not found in other fields. One given material can behave in very different ways if its size is reduced; some properties change, and effects that are unimportant at the macroscale become more relevant. The same way that aluminum, which at normal scale is relatively unreactive but burns violently when in powder, many materials become more reactive when they are made into nanoscopic objects. Other properties can change such as electrical and thermal conductivity, radiation absorption and mechanical properties. This, on the one hand, poses a challenge because it means that nanomaterials can be sometimes harder to manipulate, more sensitive to perturbations and, occasionally, more dangerous than their natural scale counterparts. At the same time, these new properties are the largest selling point of nanoscience: the motivation to work at reduced scale is not, after all, the lack of space, but the vast range of possibilities that become available. From these unique properties are steaming the new applications in such a diversity of fields as biomedicine, electronic, new energies, environment or cosmology, to name just a few.
And it is here that we stop talking just about nanoscience, and we introduce nanotechnology, which could be defined as the set of techniques and instruments that allow the characterization and manipulation of matter at the nanoscale. These techniques allow us to understand, control and design the new properties exhibited by the nanomaterials.
It is not strange, then, that nanoscience and nanotechnology are often used interchangeably, and that especially in public settings one talks just about nanotechnology, or simply nano. Therefore, to the question “What is nano?” one could give several possible answers, but all of them have in common a new approach of science that includes an interdisciplinary effort in research and development of materials at the nanoscale.