Through billions of years of evolution, Nature came up with complex self-assembled architectures capable of performing functions crucial for biological machinery to operate seamlessly. These self-assembled structures are highly dynamic and possess the capability to grow, adapt and reconfigure. For example, the cytoskeleton protein filaments are highly dynamic non-equilibrium self-assemblies that show remarkable spatiotemporal control over functions that regulate cell life-cycle, motility and so forth. Creating synthetic self-assembled architectures that can demonstrate such dynamic and adaptive behavior can lead to materials with precise control over properties with potential application in diverse fields, from drug delivery to sensing. Nucleic acid (NA) nanotechnology is a powerful tool in this regard as it offers great programmability and versatility through simple modification of strand sequences. By rationally designing the NA sequences according to Watson-Crick-Franklin base-pairing rules, parts of the different strands can be made complementary to each other, which can then hybridize to give rise to desired morphologies. Using the assembly of DNA tiles interacting through their sticky ends, self-assembled nanotubes have been produced which resemble the cytoskeleton and actin filaments from a structural viewpoint. Although reconfigurability of DNA nanostructures is possible by using strategies such as strand displacement, electrostatic suprafolding and photocontrol, building structures capable of spontaneous growth and morphological adaptation is challenging yet highly desirable. In fact, most DNA nanostructures produced to date have a definite size and shape with limitations in both space and time. In the case of DNA origami, for instance, the limitation in space is mainly due to the use of a scaffold that restricts the size of the final objects to around or below 100 nm. Several alternatives to this approach have been proposed, from scaffold-free self-assembly protocols to self-assembly of pre-formed origamis. However, in most of these cases, the formation of the targeted assembly has required the use of a thermal annealing step where the initial mixture containing the DNA strands is heated above the DNA melting temperature prior to a slow cooling down process. This creates a strong temporal constraint as the resulting nanostructures are thermodynamically stable and usually do not display dynamic behavior or evolve anymore in shape and size over time. Isothermal assembly is an interesting alternative to achieve dynamic structures because, by fixing the temperature, structures can be intrinsically more reconfigurable and free to evolve, and potentially grow, without any time constraints. It was shown, for instance, that using a simple buffer composed of NaCl, complex cocktails of DNA strands could self-assemble at room temperature into elaborate nanostructures, which not only reproduced the desired DNA-encoded morphology but were also highly reconfigurable and capable of shape selection, optimisation and transformation. This approach was applied to the isothermal self-assembly of DNA origamis and single-stranded tiles, leading to two-or three-dimensional objects no larger than 100 nm. Using strands coding for self-repeating units, nanogrids were produced but defect-free assembly of a maximum of a few hundred of nm were observed. To explore the possibility of building longer-growing nanostructures that could approach cytoskeleton dimensions and dynamic organization, we selected a system consisting of merely five oligonucleotides forming a double-crossover tile that further assembles into cylindrical nanostructures called nanotubes. This design has been studied for many years, including for constructing biomimetic endo-or exo-cytoskeletons, but nanotubes were always obtained either by thermal annealing or by the self-assembly of pre-annealed tiles, limiting possibilities of growth and evolution at fixed temperature. In this work, the oligonucleotides are mixed in an NaCl buffer and we study their evolution over time at room temperature, without any thermal pre-or post-treatment (Figure ). Notably, we observe the autonomous formation of nanotubes growing into very large dimensions and self-organizing into dynamic networks when confined in biomimetic compartments. Using fluorescence, transmission electron and cryo-electron microscopy, we characterize the dynamic and structural features of these live-growing structures in bulk, in droplets and in giant liposomes.