Impact of polymer hydrophilicity on biocompatibility: Implication for DES polymer design

Abstract

Polymer coatings are essential for local delivery of drug from the stent platform. In designing a DES, it is critical to balance the hydrophilic and hydrophobic components of the polymer system to obtain optimal biocompatibility, while maintaining controlled drug elution. This study investigates the impact of polymer composition of the BioLinx polymer blend on in vitro biocompatibility, as measured by monocytic adhesion. Comparable evaluation was performed with polymers similar to those utilized in various DES that are currently being marketed. Relative hydrophilicities of polymer surfaces were determined through contact angle measurements and surface analyses. Polymer biocompatibility was evaluated in a novel in vitro assay system in which activated monocyte cells were exposed to polymer coated on 96-well plates. Enhanced monocyte adhesion was observed with polymers of a more hydrophobic nature, whereas those which were more hydrophilic did not induce activated monocyte adhesion. Our data supports the hypothesis that polymer composition is a feature that dictates in vitro biocompatibility as measured by monocyte driven inflammation. Monocyte adhesion has been shown to induce local inflammation as well as promote vascular cell proliferation factors contributing to in stent restenosis (Rogers et al., Arterioscler Thromb Vasc Biol 1996;16:1312-1318). Observed results suggest hydrophobic but not hydrophilic polymer surfaces support adhesion of activated monocytes to the polymer scaffold. The proprietary DES polymer blend BioLinx has a hydrophilic surface architecture and does not induce an inflammatory response as measured by these in vitro assays.

Impact of Polymer Formulations on Neointimal Proliferation After Zotarolimus-Eluting Stent With Different Polymers

“…In an in vitro test, C10/C19/PVP polymer and PC showed similar hydrophilicity evaluated by contact angle and monocytic adhesion to polymer surface, suggesting similar biocompatibility with PC. 27 The current IVUS study was to test this hypothesis in clinical settings, but further studies with longer-term follow-up are required to determine whether the Resolute stents can show prolonged clinical safety similar to that observed in the Endeavor stents, owing to the similar characteristics of the C10/C19/PVP polymer to PC polymer on the surface.…”

Functionalizing PLGA and PLGA Derivatives for Drug Delivery and Tissue Regeneration Applications

“…[52] Hezi-Yamit et al studied the biological behavior of hydrophobic and hydrophilic polymers, and concluded that the hydrophobicity is associated with an accentuated inflammatory response based on the adhesion of inflammatory activated monocytes on polymers surface. [53] Therefore, the hydrophobicity of the polymeric materials applied in the tissue regeneration and drug delivery field should be carefully tuned in order to prevent undesired host responses.…”

Early Neointimal Coverage and Vasodilator Response Following Biodegradable Polymer Sirolimus-Eluting vs. Durable Polymer Zotarolimus-Eluting Stents in Patients With Acute Coronary Syndrome

“…The sirolimus us-eluting stents compared with durable polymer sirolimuseluting stents (SES), as demonstrated on OCT at 9-month follow-up, 6 but not compared with durable polymer everolimus-eluting stents (DP-EES). 7 In a bench-top study, the biocompatible BioLinx polymer did not induce activated monocyte adhesion. 8 BioLinx polymer-coated zotarolimus-eluting stent (ZES) was associated with low rates of uncovered and malapposed struts on OCT at 13 months.…”