In the first and second decades of the 21st century nanotechnology has given impetus to a new generation of materials namely
smart materials. Having the abilities to transform in shape, to sense and correspond to external stimuli like temperature, pressure,
sound, etc. and to counteract these, they excited the engineers into many new concepts like adaptive structures in aeronautics, active
biomaterials and smart self-healing composite materials. This scheme was corroborated by the parallel progress in nanotechnology,
as well as a real explosion in the additive manufacturing technologies, which enabled many types of sensors and smart or responsive
nanomaterials to be incorporated into structural parts. This mini review paper provides an opinion on these new conceptual
technologies such as 4D printing into the oncoming third decade of the century which has already been characterized as the era of
nano - and bio- engineering.