Contributions of adhesive proteins to the cellular and bacterial response to surfaces treated with bioactive polymers: case of poly(sodium styrene sulfonate) grafted titanium surfaces

Abstract

The research developed on functionalized model or prosthetic surfaces with bioactive polymers has raised the possibility to modulate and/or control the biological in vitro and in vivo responses to synthetic biomaterials. The mechanisms underlying the bioactivity exhibited by sulfonated groups on surfaces involves both selective adsorption and conformational changes of adsorbed proteins. Indeed, surfaces functionalized by grafting poly(sodium styrene sulfonate) [poly(NaSS)] modulate the cellular and bacterial response by inducing specific interactions with fibronectin (Fn). Once implanted, a biomaterial surface is exposed to a milieu of many proteins that compete for the surface which dictates the subsequent biological response. Once understood, this can be controlled by dictating exposure of active binding sites. In this in vitro study, we report the influence of binary mixtures of proteins [albumin (BSA), Fn and collagen type I (Col I)] adsorbed on poly(NaSS) grafted Ti6Al4V on the adhesion and differentiation of MC3T3-E1 osteoblast-like cells and the adhesion and proliferation of Staphylococcus aureus (S. aureus). Outcomes showed that poly(NaSS) stimulated cell spreading, attachment strength, differentiation and mineralization, whatever the nature of protein provided at the interface compared with ungrafted Ti6Al4V (control). While in competition, Fn and Col I were capable of prevailing over BSA. Fn played an important role in the early interactions of the cells with the surface, while Col I was responsible for increased alkaline phosphatase, calcium and phosphate productions associated with differentiation. Poly(NaSS) grafted surfaces decreased the adhesion of S. aureus and the presence of Fn on these chemically altered surfaces increased bacterial resistance ≈70% compared to the ungrafted Ti6Al4V. Overall, our study showed that poly(NaSS) grafted Ti6Al4V selectively adsorbed proteins (particularly Fn) promoting the adhesion and differentiation of osteoblast-like cells while reducing bacterial adhesion to create a bioactive surface with potential for orthopaedic applications.

Review of titanium surface modification techniques and coatings for antibacterial applications

“…The "grafting from" approach (Scheme 1) has attracted considerable attention in recent years for the preparation of tethered polymers onto a solid substrate surface [106]. The direct grafting of an ionic polymer model such as poly(sodium styrene sulfonate (polyNaSS) (Scheme 1) in a two-step reaction procedure onto titanium and alloy titanium surfaces was reported [106][107][108][109][110][111][112][113]. Treatment of the titanium surface by a mixture of sulfuric acid and hydrogen peroxide generates titanium hydroxide and titanium peroxide.…”

“…In the second reaction step, heating or UV irradiation of surfaces, if the substrate is placed in a concentrated solution of sodium styrene sulfonate monomer (NaSS) monomer, induces the decomposition of titanium peroxides with the formation of radicals capable of initiating the polymerization of NaSS. [107][108][109][110][111][112][113] A great advantage of polyNaSS grafting relies on its bioactivity, which could partly be explained by its moderate hydrophilic character. A bacterial adhesion study showed that titanium and titanium alloy graft surfaces exhibited high inhibition of S. aureus adhesion at levels greater than 70% when compared to non-grafted titanium and titanium alloy surfaces.…”

Bacterial adhesion mechanisms on dental implant surfaces and the influencing factors

“…Such modified titanium surfaces provide us a promising strategy for preventing biofilm-related infections and enhancing osteointegration of implants in dental applications [157], due to its osteoblastic selective nature by its sulphonate group [158,159] and the negative charge might be the reason for antibacterial property [160].…”

Sulfonate-modified phenylboronic acid-rich nanoparticles as a novel mucoadhesive drug delivery system for vaginal administration of protein therapeutics: improved stability, mucin-dependent release and effective intravaginal placement

“…27 Here, sulfonated monomers were included in the synthesis of nanoparticles to provide stable negative charges as proven by the zeta potential data throughout a wide pH range ( Figure 2C), similar to previous literature on improved colloidal stability of poly(styrenesulfonate)-coated nanoparticles assessed through sedimentation tests. 28 In contrast, the zeta potential of PBNP was close to zero in the pH range 7-7.5, in accordance with the aggregation tendency of PBNP in this pH range ( Figure 2B) or over storage (Figure 3).…”