Fibronectin adsorption and arrangement on copolymer surfaces and their significance in cell adhesion

Abstract

The adsorption of fibronectin (FN) to (styrene/methyl methacrylate) copolymer surfaces, both sulfonated (hydrophilic) and nonsulfonated (hydrophobic), was studied by means of the radioisotope (125I-FN) and ELISA assays; the latter employed monoclonal antibodies. It was found that the radioiodination-derived isotherms did not follow the Langmuir-type adsorption law within the FN concentration range studied; rather, a quasi-linear FN surface density versus bulk concentration dependence was observed. These isotherms, and our recent ELISA measurements with polyclonal antibodies, allowed us to estimate saturative FN surface densities, which were, within the experimental error, similar on both types of surfaces. This suggested the amount of adsorbed FN to be not responsible for observed differences in leukaemia L1210 cell adhesion (FN-coated sulfonated surfaces are far more pro-adhesive than their nonsulfonated analogues). The presumption that these differences are induced by changes in the FN arrangement was confirmed by the use of monoclonal antibodies directed against distinct FN domains, and by the blocking of alpha5beta1 integrin receptor with the synthetic Gly-Arg-Gly-Asp-Ser-Pro (GRGDSP) peptide. The RGD sequence located within the FN cell-binding domain seems to be masked in the structure adopted on nonsulfonated surfaces, which hinders the integrin-ligand interaction.

Interaction of PC-3 cells with fibronectin adsorbed on sulfonated polystyrene surfaces

“…In the earlier studies by Kowalczyńska et al [12,13], it was shown that sulfonic groups on styrene copolymer surfaces have a stimulatory effect on the adhesion of L1210 and 3T3 cells. In the case of 3T3 cells, the number of adhering cells correlated, while the number of non-spherical cells inversely correlated, with the surface density of sulfonic groups [17].…”

“…surface roughness), and on the environmental conditions (e.g. pH value, ionic strength and temperature) [9][10][11][12][13][14][15]. As a result of adsorption, FN conformation can become compact or extended, depending on physicochemical conditions.…”

“…As a result of adsorption, FN conformation can become compact or extended, depending on physicochemical conditions. It has been observed that adhesion of normal and cancer cells to substrate surfaces containing chemical groups with a negative charge (-SO 3 H, -OH, -COOH) or a positive charge (-NH 2 ) depends on surface wettability and the conformation of the protein molecule on the surface [9,[11][12][13][14][15][16][17][18][19]. Fibronectin adsorbed on strongly hydrophilic polystyrene surfaces, in contrast to the adsorption on hydrophobic surfaces, is characterized by extended, biologically active conformation with the unfolded cellbinding domain (CCBD), which stimulates not only the early phase of adhesion, but also the cell spreading process [13,14,20,21].…”

Elements in the C terminus of apolipoprotein [a] responsible for the binding to the tenth type III module of human fibronectin

“…This observation, which in the case of Fn is in keeping with previous studies by Salonen et al (6), is not unique to the Fn-apo[a] system, because immobilization of Fn has been shown to be required for the binding of Fn to plasminogen, tissue-type plasminogen activator (35), and acute-phase C-reactive protein (36). In this regard, recent studies have shown that Fn undergoes a conformational transition from a closed form to an open form when moving from a solution to a solid phase (37,38). Noteworthy, this notion explains why Fn and apo [a] do not interact with each other in the circulating plasma.…”

Designing nanostructured block copolymer surfaces to control protein adhesion

“…Block copolymers have also found application in biomaterials for both mechanical [68][69][70] and biological properties. There are many biological applications for block copolymers, including micelles for drug delivery [71][72][73][74], spacing bioactive groups on a surface [54,59,60,75,76] and controlling cellular and protein adhesion [25,[51][52][53]57,[77][78][79][80][81]. Despite the wide variety of applications, there does not appear to have been a systematic exploration of the structure-property relationship between block copolymers and biological systems.…”