Incorporation of a Clot-Binding Peptide into Polythiophene: Properties of Composites for Biomedical Applications

Abstract

Biocomposites formed by a pentapeptide (CREKA), which recognizes clotted plasma proteins, entrapped into the poly(3,4-ethylenedioxythiophene) (PEDOT) matrix have been prepared using three very different procedures. X-ray photoelectron spectroscopy analyses indicate that PEDOT-CREKA films, prepared by chronoamperometry in basic aqueous solution (pH = 10.3) and deposited onto a PEDOT internal layer, present the higher concentration of peptide: one CREKA molecule per six polymer repeat units. The surface of this bilayered system shows numerous folds homogeneously distributed, which have been exhaustively characterized by scanning electron microscopy and atomic force microscopy. Indeed, the morphology and topography of such bilayered films is completely different from those of biocomposite-prepared acid aqueous and organic solutions as polymerization media. The impact of the entrapped peptide molecules in the electrochemical properties of the conducting polymer has been found to be practically negligible. In contrast, biocompatibility assays with two different cellular lines indicate that PEDOT-CREKA favors cellular proliferation, which has been attributed to the binding of the peptide to the fibrin molecules from the serum used as a supplement in the culture medium. The latter assumption has been corroborated examining the ability of PEDOT-CREKA to bind fibrin. The latter ability has been also used to explore an alternative strategy based on the treatment of PEDOT-CREKA with fibrin to promote cell attachment and growth. Overall, the results suggest that PEDOT-CREKA is appropriated for multiple biomedical applications combining the electrochemical properties of conducting polymer and the ability of the peptide to recognize and bind proteins.

Electroactive polymer–peptide conjugates for adhesive biointerfaces

“…Deconvolution of the C1s peak led to five Gaussian curves that has been attributed to saturated and conjugated C-C (284.5 eV) and C=C-O (286.4 eV) bonds of PEDOT chains, 30,31 the C=O of amide (288.3 eV), 32,33 the C-N bonds of guanidinium group in Arg (289.6 eV) 33 and the C-F bonds of residual TFA molecules (292.2 eV) 33 arising from the deprotection step in the synthesis ( Figure 2). The high resolution N1s spectrum shows a peak centered at 400.3 eV, which seems to include both the guanidinium (400.1 eV) and the backbone amide (400.6 eV) signals identified for the RGD peptide sequence.…”

“…23 The O1s signal consists of three components, with the most intense one at 533.3 eV corresponding to the C-O-C bond in the ethylene bridge of PEDOT. 30 The component at 531.4 eV is assigned to the carboxylate groups in the conjugated RG E D peptide 33 while the peak at 535.2 eV corresponds to the C=O of contamination products (e.g. CO 2 adsorbed from the atmosphere).…”

Examining the compatibility of collagen and a polythiophene derivative for the preparation of bioactive platforms

“…For the selection of appropriated models, it should be noted that the excellent behavior of CP-biomolecule composites as bioactive platforms is essentially due to the ability of CPs to exchange ions with cells and to the favorable biomolecule···cell interactions. 10,28,31 In contrast, properties related with electron delocalization along polymer chains are not relevant for for bioactivity. Accordingly, selection of small model compounds was considered appropriate for understanding the specific interactions between the components of P(EDOT:CLG).…”

“…1 For example, CP coatings and films have been used to fabricate active surfaces for the selective adsorption of proteins, 2,3 polymeric 2D-and 3D scaffolds for tissue engineering, [4][5][6][7][8] bioactive functionalized platforms [9][10][11] and bioelectrodes. 12,13 Combination of collagen, which is the major structural protein in animals, with synthetic polymers is a good approach for the fabrication of composite scaffolds for tissue engineering.…”

Multifunctional Biomimetic Scaffolds Tailored for Cardiac Regeneration

“…224,225 Degradable conjugated polymers of pyrrole/thiophenes tethered by ester bonds were also developed and showed a conductivity of 10 -4 Scm -1 .…”