Hyaluronic acid/poly-L-lysine multilayers coated with gold nanoparticles: Cellular response and permeability study

Polyelectrolyte multilayer films have been widely studied over the past decade for bioapplications due to their proven reservoir properties for proteins and peptides, growth factors, nucleic acids, drugs, etc. Thick (micrometer-sized) and soft multilayer films made of biopolymers possess high reservoir capacity but are usually cell repellent. Recently, a new approach has been developed based on physical modification of the films made from hyaluronic acid (HA) and poly-L-lysine (PLL) by coating film surface with gold nanoparticles (AuNP). This allows stiffening of the soft HA/PLL film, but still keeps the main part of the film intact to ensure its reservoir ability. Here we have studied cellular adhesion and permeability of the AuNP-coated films. Different cell types (neuronal SH-SY5Y, L929 fibroblasts, human embryonic kidney HEK 293 cells, and cervical cancer HELA cells) have been examined. Film free regions formed by mechanical scratching have been used as controls for cellular adhesion. For the permeability study small dye carboxyfluorescein (CF) and large macromolecule (PLL) have been utilized. As found in this study, (HA/PLL)(24) films are cell repellent for all considered cell lines. But an improved adhesion to the AuNP-coated films has been observed for all the cells lines except of HEK. AuNP coating leads to formation of a kind of semipermeable layer on the film surface, which allows small molecules such as CF to diffuse fast into the film, while diffusion of large molecules (PLL) is hindered. Being cell adhesive and selectively permeable AuNP-coated multilayer films could serve as a novel platform for film-mediated controlled drug delivery.