Layer-by-Layer Deposition of a Polycationic Bottlebrush Polymer with Hyaluronic Acid Reveals Unusual Assembly Mechanism and Selective Effect on Cell Adhesion and Fate

This study provides a detailed molecular mechanism of the layer-by-layer (LbL) film formation process involving BB polymers. The roles of adsorbed and non-adsorbed chain segments during the layer buildup are revealed by employing surface force apparatus (SFA) and atomic force microscopy (AFM) to probe critical aspects such as surface coverage, polymer conformation at the surface, adhesive properties, and morphology after each layer deposition. The results show that the thickness, nanomechanical properties, and surface chemistry of the nanofilms are significantly influenced by the number of layers. All these cues have an important impact on cell behavior when employed as coatings for culture substrates. The evidence is shown that cells respond very differently to these cues and exhibit behavior that goes from superproliferation down to accelerated death. Non-adsorbed polymer chains result in island formation during layer-by-layer (LbL) deposition, impacting morphology, roughness, surface chemistry, and mechanical properties of LbL nanofilms. These properties can be used to tune cell behavior, including morphology and cell proliferation. These insights emphasize the potential of LbL techniques for precise manipulation of cell behavior and the design of tailored cellular microenvironments. image