ABSTRACT
Cells, the basic building blocks of life, are spatially structured, yet highly dynamic factories that produce almost everything an organism needs. Their functions require that they communicate with each other on many levels and timescales, from millisecond electronic communication in the heart to synchronize contraction, to communication lasting minutes, hours, and even days, and over long distances across the body via chemical messengers, such as hormones. Many human diseases are caused by erroneous signal procession: diabetes is either cause by the inability to produce the signaling hormone insulin or by the desensitization of its receptor; the majority of cancers result from erroneous processing of growth signaling delivered by growth hormones. Hence, the development of tools to communicate with cells inside the intact organism is of great interest for basic research and new therapeutic approaches. Ideally, we find ways to read out the state of single cell and then relate back a message to a cell without having to disrupt the organism.
