Investigation of the Structural Mechanism and Film Growth on Cytoprotective Type I Collagen-Based Nanocoating of Individual Cellular Surfaces.

Cell surface coating using the layer-by-layer assembly (LbL) method has many advantages for biomedical applications. Because the cell surface is a dynamic and highly complex structure, it is hypothesized that LbL multilayer films on cells have characteristics different from those observed in traditional film characterization results. Here, to demonstrate the mechanism of LbL-film formation on cells, LbL films are prepared on HeLa cells using collagen (Col) and hyaluronic acid (HA). The growth behavior of the film and the main driving forces inducing the formation of an LbL film on the cells are investigated. Col self-assembles via electrostatic and hydrophobic interactions; therefore, the Col-based film on the cells grows laterally rather than volumetrically. For the film construction conditions, the ionic density and chain conformation of the polymers change, resulting in mainly hydrophobic interactions. Additional interactions, such as hydrophobic interactions and biological recognition between the substrate and building blocks, also exist and tightly stabilize the films on the cells. The Col/HA film shows an even distribution on the cell surface as the extracellular matrix, and it activates proliferation and the cytoprotective signaling pathway under harsh conditions, resulting in the focal adhesion kinase signaling pathway and low lactate dehydrogenase release. Therefore, information for film construction on cells is beneficial to understand the effectiveness of an LbL film for cells.