title: Polyelectrolyte multilayers and degradable polymer layers as multicompartment films.
abstract: Polyelectrolyte multilayers are now a well established concept with numerous potential applications in particular as biomaterial coatings. To timely control the biological activity of cells in contact with a substrate, multicompartment films made of different polyelectrolyte multilayers deposited sequentially on the solid substrate constitute a promising new approach. In a first paper (Langmuir 2004, 20, 7298) we showed that such multicompartment films can be designed by alternating exponentially growing polyelectrolyte multilayers acting as reservoirs and linearly growing ones acting as barriers. In the present study, we first demonstrate however that these barriers composed of synthetic polyelectrolytes are not degraded despite the presence of phagocytic cells. We propose an alternative approach where exponentially growing poly(L-lysine)/hyaluronic acid (PLL/HA) multilayers, used as reservoirs, are alternated with biodegradable polymer layers consisting in poly(lactic-co-glycolic acid) (PLGA) and acting as barriers for PLL chains that diffuse within the PLL/HA reservoirs. We first show that these PLGA layers can be deposited alternatively with PLL/HA multilayers leading to polyelectrolyte multilayer/hydrolyzable polymeric layer films and acting as a reservoirs/barriers system. Bone marrow cells seeded on these films ending by a PLL/HA reservoir rapidly degrade it and internalize the PLL chains confined in this reservoir. Then the cells degraded locally the PLGA barrier and internalize the PLL localized in a lower (PLL/HA) compartment after 5 days of seeding. By changing the thickness of the PLGA layer, we hope to be able to tune the time delay of degradation. Such mixed architectures made of polyelectrolyte multilayers and hydrolyzable polymeric layers could act as coatings allowing us to induce a time scheduled cascade of biological activities. We are currently working on the use of comparable films with compartments filled by proteins or peptides and in which the degradation of the barriers results from a hydrolysis over tunable time scales.
authors.affiliation: INSERM U595, Strasbourg, F-67085, and Faculté de Chirurgie Dentaire, Université Louis Pasteur, Strasbourg, F-67085 France.
authors.forename: Juan Méndez
authors.initials: JM
authors.lastname: Garza
authors.forename: Nadia
authors.initials: N
authors.lastname: Jessel
authors.forename: Guy
authors.initials: G
authors.lastname: Ladam
authors.forename: Valérie
authors.initials: V
authors.lastname: Dupray
authors.forename: Sylvaine
authors.initials: S
authors.lastname: Muller
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Stoltz
authors.forename: Pierre
authors.initials: P
authors.lastname: Schaaf
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Voegel
authors.forename: Philippe
authors.initials: P
authors.lastname: Lavalle