Fluorinated surface‐modifying macromolecules: Modulating adhesive protein and platelet interactions on a polyether‐urethane

Abstract

Polyether-urethanes (PEUs) have been the materials of choice for the manufacture of conventional blood-contacting devices. Nevertheless, biostability and blood compatibility are still among the principal limitations in their long-term application. Studies investigating the development of protective coatings for PEUs have shown that degradation can be reduced with the use of fluorinated surface-modifying macromolecules (SMMs). It has also been hypothesized that SMM-modified PEU surfaces may exhibit improved blood compatibility because other studies have shown a modulation in fibrinogen adsorption onto these surfaces. To determine the blood compatibility of a PEU-containing fluorinated SMMs, a series of in vitro experiments were designed to study the pattern of protein adsorption from plasma and then to assess the nature of platelet adhesion and activation on each substrate. Western blot analysis as well as single protein studies revealed that the dominant "adhesive proteins" [fibrinogen (Fg), fibronectin (Fnc), and vitronectin (Vnc)] were adsorbed on two of the SMM-containing PEUs in lower amounts relative to unmodified base. Platelet adhesion and activation data further highlighted the differences among the various substrates. It was shown that the unmodified base had a higher number of adhered platelets relative to the SMM-modified surfaces, and that of the SMM-containing substrates, which showed the lowest levels of adhesive proteins also, exhibited significantly lower platelet densities. Close morphological examination further revealed that platelets residing on these latter substrates were not appreciably activated. Based on the current evidence, it is believed that the fluorinated SMMs demonstrate good potential for the development of surfaces with minimal thrombogenic character in in vivo applications.

Generation of cell adhesive substrates using peptide fluoralkyl surface modifiers

“…The synthesis of the BFSM ester precursor reproducibly yielded a polymer with a weight average molecular weight of 18,000 g/mol (polystyrene equivalent MW), consistent with SMM MWs reported in the literature [6,7]. A value for the BFSM acid precursor MW could not be established using the GPC, given that the retention time was located outside of the universal calibration range, and the peak magnitude was sharply diminished relative to the ester and phenylalanine BFSM peaks (Fig.…”

“…7, the initial population of monocytes on the SMM surface decreased with time, while the PCNU supported a stable population. The SMM data confirmed the non-adhesive nature of fluorinated substrates in controlling cellular interaction with polymer surfaces [7,43]. The second aspect of monocyte adhesion concerns adhesive ligand presentation, and how to best fabricate a bioactive surface.…”

“…Data are reported with standard error. reduce protein adhesion has included grafting polyethylene oxide (PEO) [38][39][40][41], and the use of SMMs [7]. Further, macrophage interactions with polycarbonate polyurethanes has been studied by Labow et al in significant detail, and the PCNU used in this study was identified as mildly pro-inflammatory compared to other PCNU formulations [42].…”

“…The oligomeric backbone of the SMM is chemically tailored to be compatible with the bulk polymer, so that the SMM can form strong stable interactions with the bulk polymer without compromising the mechanical properties of the device. The SMM enriched surfaces have been shown to reduce the thrombogenicity of polyurethanes [7] and in some cases provide protection from enzymatic hydrolysis, a degradation phenomenon associated with macrophages [8].…”

Surface Modification of PVC Membranes Using Fluorothiophenol Compounds

“…[31][32][33] These surfaces derive their characteristics from the unique molecular properties associated with the CÀF bond that imparts a specific, unique chemistry and physics at interfaces. In this sense, fluoride compounds can be used as modifier in order to introduce these kinds of properties to different commodity polymers.…”