Nucleotides trigger the spontaneous emergence of hierarchical nanolamellar architectures in coacervate-like polyelectrolyte multilayers

Spontaneous generation of hierarchical order over multiple length scales remains a major challenge in soft materials because it typically relies on external patterning or multistep fabrication strategies. Here we show that a coacervate-like, exponentially growing poly(L-lysine)/hyaluronic acid (PLL/HA) multilayer autonomously reorganizes into a hierarchical architecture following simple exposure to ATP under aqueous conditions. Within minutes, the initially homogeneous film evolves into a sponge-like network of micrometer-sized cavities separated by thin walls containing PLL, HA and ATP. Cryogenic scanning electron microscopy and small-angle X-ray scattering independently reveal that these walls possess a short-range one-dimensional lamellar paracrystalline organization, demonstrating the emergence of structural order at both the micro- and nanoscales. The extent of this reorganization depends on the ATP concentration: 2 mM concentration of ATP produces a stable hierarchical morphology, whereas high ATP concentration drives complete film dissolution. Comparison with guanosine and uridine triphosphate (GTP and UTP) demonstrates that the self-organization process depends on the chemical nature of the nucleobase since, under exactly the same conditions, only ATP and GTP lead to a mesostructured formation. All our observations are consistent with a mechanistic framework in which a suitable nucleotide, i.e. ATP or GTP, progressively remodels the coacervate-like network, leading to an internal phase separation that may evolve into a lamellar structure through a surface-directed process. More broadly, this work identifies hydrated polyelectrolyte assemblies such as exponentially growing polyelectrolyte films, as a simple experimental platform in which diffusion-driven compositional changes can generate hierarchical periodic micro- and nanostructures without external templating.