A nanosensor is a very small (i.e. nanoscale) system capable of detecting and responding to some type of input from a biological, chemical or physical environment. Among others, physical inputs can be light, heat, motion, moisture or pressure. Generally, the output is a signal that is converted to a ready-to-read signal for the user normally through a device display.
A nanocapsule is a very small (i.e. nanoscale) shell which is mainly made by a non-toxic polymer. The inner core of the nanocapsule can contain liquid substances, normally water-based or oily emulsions, that ensure the transport of certain drugs or nanosensors, for example.
The nanocapsules can be either naked or surface-functionalized with other compounds for providing them with extra functionalities. For instance, the nanocapsules can be coated with certain antibodies that will target them towards the specific cells expressing the antigen that reacts to that antibody, bringing specificity to the whole system.
During the HypoSens project, a nanocapsule with anti-HER2 antibodies in the surface has been developed. The antibodies target the nanocapsule specifically towards cancer cells that express the HER-2 protein (i.e. antigen) which is a receptor related to a particular type of breast cancer cells. The inner part of the nanocapsule contains nanosensors for oxygen and temperature since the values of these parameters correlate to the presence of cancer cells: tumours are low in oxygen content and have higher temperature due to their different metabolic needs. With these 3 specific check points, the system will be highly specific and therefore accurate.