From chiselled silica-crafting diatoms to migrating blue wildebeests, living matter manifests itself in an exceptional diversity of morphologies and functions. Perhaps even more amazing is that this astonishing diversity is encoded in the same and highly conserved molecule, DNA, the molecular code of life. Neglecting its biological role, a pragmatic soft matter scientist would rather see DNA as a common semi-flexible anionic polyelectrolyte (a polymer carrying negative charges). And because now any synthetic DNA of virtually any sequence and length can be easily purchased at low cost, it has become also an ordinary brick game for researchers combining DNA sequences to build exquisite materials (DNA nanotechnology) or express useful proteins (synthetic biology).

In this talk, I would like to show how astonishing DNA remains, at least to me, precisely by remembering it is both intrinsically soft and capable to program (structures and functions). I will show in particular how this has allowed us to control gene expression using light in a non-invasive way; to build an animal-free, fully synthetic antibody discovery platform; or to create user-defined DNA nanostructures with a unique capability to self-assemble under physiological conditions as well as to adapt, evolve and even completely transform their morphology, either spontaneously or under command. And because self-assembly can occur without DNA, I may also present an original concept of sickle-cell diagnostics inspired by the stain left by a spilled coffee drop after drying.