Conducting Polymer-Infused Electrospun Fibre Mat Modified by POEGMA Brushes as Antifouling Biointerface

Abstract

Biofouling on surfaces, caused by the assimilation of proteins, peptides, lipids and microorganisms, leads to contamination, deterioration and failure of biomedical devices and causes implants rejection. To address these issues, various antifouling strategies have been extensively studied, including polyethylene glycol-based polymer brushes. Conducting polymers-based biointerfaces have emerged as advanced surfaces for interfacing biological tissues and organs with electronics. Antifouling of such biointerfaces is a challenge. In this study, we fabricated electrospun fibre mats from sulphonated polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (sSEBS), infused with conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) (sSEBS-PEDOT), to produce a conductive (2.06 ± 0.1 S/cm), highly porous, fibre mat that can be used as a biointerface in bioelectronic applications. To afford antifouling, here the poly(oligo (ethylene glycol) methyl ether methacrylate) (POEGMA) brushes were grafted onto the sSEBS-PEDOT conducting fibre mats via surface-initiated atom transfer radical polymerization technique (SI-ATRP). For that, a copolymer of EDOT and an EDOT derivative with SI-ATRP initiating sites, 3,4-ethylenedioxythiophene) methyl 2-bromopropanoate (EDOTBr), was firstly electropolymerized on the sSEBS-PEDOT fibre mat to provide sSEBS-PEDOT/P(EDOT-co-EDOTBr). The POEGMA brushes were grafted from the sSEBS-PEDOT/P(EDOT-co-EDOTBr) and the polymerization kinetics confirmed the successful growth of the brushes. Fibre mats with 10-mers and 30-mers POEGMA brushes were studied for antifouling using a BCA protein assay. The mats with 30-mers grafted brushes exhibited excellent antifouling efficiency, ~82% of proteins repelled, compared to the pristine sSEBS-PEDOT fibre mat. The grafted fibre mats exhibited cell viability >80%, comparable to the standard cell culture plate controls. Such conducting, porous biointerfaces with POEGMA grafted brushes are suitable for applications in various biomedical devices, including biosensors, liquid biopsy, wound healing substrates and drug delivery systems.

Keywords: BSA; POEGMA brush; antifouling; cell viability and proliferation; conducting polymer; electrospinning; proteins.

Figure 1

Schematic representation of fabrication of sSEBS-PEDOT/P(EDOT-co-EDOTBr) fibre mat with grafted POEGMA brushes.

Figure 2

SEM images of (A) an electrospun sSEBS fibre mat (inset: photographs of sSEBS fibre mat), (B) PEDOT coated conducting electrospun fibre mat (sSEBS-PEDOT) (inset: photographs of sSEBS-PEDOT fibre mat), (C) Raman spectra of pristine and PEDOT coated electrospun sSEBS fibre mat, (D) Cyclic voltammograms of the electrodeposition of P(EDOT-co-EDOTBr) (10:1 mol:mol) onto sSEBS-PEDOT in the potential range of -0.5 V to +1.5 V at 100 mV/s for 10 cycles, in 0.1 M LiClO₄ in acetonitrile, and (E) XPS spectra of Br 3d of sSEBS-PEDOT fibre mat (red) and sSEBS-PEDOT/P(EDOT-co-EDOTBr) fibre mat (blue).

Figure 3

(A) SI-ATRP kinetics graph for POEGMA grafting on electrospun fibre mats, (B) Contact angle measurement of sSEBS, sSEBS-PEDOT, sSEBS-PEDOT/P(EDOT-co-EDOTBr) and sSEBS-PEDOT/P(EDOT-co-EDOTBr)-g-POEGMA (30-mers) fibre mat, (C) SEM image of sSEBS-PEDOT/P(EDOT-co-EDOTBr)-g-POEGMA (30-mers) fibre mat, and (D) Conductivity of the sSEBS-PEDOT and sSEBS-PEDOT/P(EDOT-co-EDOTBr)-g-POEGMA fibre mat with 10- and 30-mers graft length (n = 5).

Figure 4

(A) The number of BSA proteins adsorbed on the grafted sSEBS-PEDOT/P(EDOT-co-EDOTBr)-g-POEGMA with 10- and 30-mers graft lengths and the sSEBS-PEDOT fibre mat, surfaces, after 2 h incubation in a solution of BSA in PBS (200 µg/mL); calculated as number per µm² of the projected area (n = 3). (B) The fluorescent signals obtained from the cells grown on the standard cell culture plate and POEGMA grafted fibre mat surface.