Biopolymer coatings on implants mediate the interactions between the synthetic material and its biological environment. Owing to its ease of preparation and the possibility to incorporate other bioactive molecules, layer-by-layer deposition is a method commonly used in the construction of biopolymer multilayers. However, this method typically requires at least two types of oppositely charged biopolymers, thus limiting the range of macromolecular options by excluding uncharged biopolymers. Here, we present a layer-by-layer approach that employs mussel-inspired polydopamine as the adhesive intermediate layer to build biopolymer multilayer coatings without requiring any additional chemical modifications. We select three biopolymers with different charge states─anionic alginate, neutral dextran, and cationic polylysine─and successfully assemble them into mono-, double-, or triple-layers. Our results demonstrate that both the layer number and the polymer type modulate the coating properties. Overall, increasing the number of layers in the coatings leads to reduced cell attachment, lower friction, and higher drug loading capacity but does not alter the surface potential. Moreover, varying the biopolymer type affects the surface potential, macrophage differentiation, lubrication performance, and drug release behavior. This proof-of-concept study offers a straightforward and universal coating method, which may broaden the use of multilayer coatings in biomedical applications.
Keywords: biomacromolecules; implant; layer-by-layer assembly; non-covalent coating; polydopamine.