Characterization of polyelectrolyte multilayer films on polyethylene terephtalate vascular prostheses under mechanical stretching

Abstract

Layer-by-layer (LBL) polyelectrolyte films offer extensive potentials to enhance surface properties of vascular biomaterials. From the time of implantation, PET prostheses are continuously subjected to multiple mechanical stresses such as important distorsions and blood pressure. In this study, three LBL films, namely (1) poly(sodium 4-styrenesulfonate)/poly(allylamine hydrochloride), (2) poly(L-lysine)/hyaluronan, and (3) poly(L-lysine)/poly(L-glutamic acid) were built on to isolated PET filaments, thread, and vascular prostheses. The three LBL films uniformly covered the surface of the PET samples with rough, totally smooth, and "wrinkled" appearances respectively for (PAH/PSS)(24), (PLL/HA)(24), and (PLL/PGA)(24) systems. We then assessed the behavior of these LBL films, in an aqueous environment [by environmental scanning electronic microscopy (ESEM)], when subjected to unidirectional longitudinal stretches. We found that stretching induces ruptures in the multilayer films on isolated filaments for longitudinal stretches of 14% for (PSS/PAH)(24), 13% for (PLL/PGA)(24), and 30% for (PLL/HA)(24) films. On threads, the rupture limit is enhanced to be respectively 26, 20, and 28%. Most interestingly, we found that on vascular prosthesis no rupture is visible in any of the three multilayers types, even for elongations of 200% (200% undergone by the PET prostheses is representative of those encountered during graft deployment) which by far exceeds elongations observed under physiological conditions (10-20%, blood pressure). In term of mechanical behaviors, these preliminary data constitute a first step toward the possible use of LBL film to coat and functionalize vascular prosthesis.

Fibrillar films obtained from sodium soap fibers and polyelectrolyte multilayers

“…The oppositely charged PAH and PSS that accumulates between the fibers can form aggregated polyelectrolyte complexes. Vautier and coworkers deposited (PAH/PSS) 24 multilayers onto 10‐μm diameter polyethylene terephthalate fibers and also observed a granular precipitate among the smoothly coated fibers 22. This suggests that PAH and PSS, but not necessarily soap surfactants, are sufficient for the formation of the precipitate that we observed.…”

Layer‐By‐Layer Films as a Biomimetic Reservoir for rhBMP‐2 Delivery: Controlled Differentiation of Myoblasts to Osteoblasts

“…These results should have an important impact on the development of biofunctionalized surfaces for tissue‐engineered constructs or for metallic implants. Indeed, as PLL/HA films were recently successfully deposited on polyethylene terephthalate prostheses59 and onto nickel–titanium implant surfaces,60 it may be envisioned that the present concept could be applied to biomaterial surfaces for investigating rhBMP‐2 effects in vivo. Much larger doses of rhBMP‐2 could indeed be loaded in PLL/HA films if necessary, by varying the number of layer pairs in the films and the deposition conditions (see Figure 3).…”

Micropatterned polyelectrolyte nanofilms promote alignment and myogenic differentiation of C2C12 cells in standard growth media

“…Since muscle regeneration requires that quiescent mononucleated muscle precursor cells become activated, proliferate, and differentiate (Engler et al, 2004), we focused on validating the impact of our microstructured surfaces on C2C12 adhesion and proliferation, as a prerequisite to myogenic differentiation. Moreover, as polyelectrolyte multilayers are employed more and more to coat implant surfaces (Rinckenbach et al, 2007), this pilot study provides the proof of principle for the rationale design of cell‐interacting materials with controlled and biocompatible surface's properties.…”