Chitosan/chondroitin sulfate multilayers as supports for calcium phosphate biomineralization

•Calcium phosphate precipitates were obtained in a nanostructured multilayer.•The bioactive multilayer was composed of weak and natural polyelectrolytes.•Films with more bilayers showed earlier calcification.•Organic–inorganic composite biomaterials can be produced by this biomimetic approach.

We investigated the interaction of natural derived macromolecular multilayers with calcium and phosphate ions entirely processed using the layer-by-layer (LbL) technique. A nanostructured multilayer component, with 5 or 10 bilayers, was first produced using weak polyelectrolyte biopolymers, chitosan and chondroitin sulfate. This was followed by sequential passing of solutions containing Ca2+ and PO43−PO43− over the multilayers. QCM-D, SEM and EDX results conferred the formation of calcium phosphate (CaP) over the polyelectrolyte multilayers. Initiation of precipitation was observed earlier in the 10 bilayers coating than in the 5 bilayers one. These results indicate the potential of multilayers to trap ions, as a biomimetic approach that can be used to induce CaP precipitation. This could enable the preparation of more performant bioactive composite biomaterials for orthopedic applications, including in bone tissue engineering.