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BP: Fachverband Biologische Physik

BP 14: Biomaterials and Biopolymers I (joint with CPP)

BP 14.2: Vortrag

Dienstag, 12. März 2013, 10:00–10:15, H34

Mechanical properties of poly-L-lysine (PLL) / hyaluronic acid (HA) multilayer films measured by AFM — •Johannes Hellwig, Cagri Üzüm, and Regine von Klitzing — Stranski-Laboratorium, Institut für Chemie,TU Berlin, Strasse des 17. Juni 124, 10623 Berlin, Germany

In recent years smart biomaterials have become a highly developing field of interest for biomedical applications, e.g. drug delivery. The layer-by-layer (LbL) technique gives the opportunity to build up self assembled polyelectolyte multilayer films (PEM) with defined architecture, physical and chemical properties. PEM made of poly-L-lysine (PLL) and hyaluronic acid (HA) were produced by using the LbL technique. Potential applications of these PEMs require controlling of the adhesion behaviour by tuning their elastic/viscoelastic properties. In this study mechanical properties of LbL coated poly(L-lysine)/hyaluronan PLL/HA films were studied by scanning- and colloidal-probe atomic force microscopy as a function of indentation velocity, number of polymer deposition steps and temperature. Film growth was investigated by two independent AFM methods: scratch-and-scan and full-indentation[1]. Film thickness increases linearly with polymer deposition steps. The Young*s modulus ranges between 15 and 40 kPa and does not depend on the film thickness. Stress relaxation and creep compliance measurements indicate a viscoelastic film behaviour with multiple relaxation mechanisms.

[1] Üzüm, C.; Hellwig, J.; Madaboosi, N.; Volodkin, D.; v. Klitzing, R. Beilstein J. Nanotechnol. 2012, 3, 778*788.