Development of a YIGSR-peptide-modified polyurethaneurea to enhance endothelialization

Abstract

Polyurethanes have been investigated for use as vascular grafts due to their excellent mechanical properties and relatively good biocompatibility. However, poor retention of endothelial cells and thrombogenicity in vivo remain problematic for vascular graft applications. The peptide YIGSR has been shown to increase endothelial cell adhesion but not attachment of platelets, suggesting its possible utility for vascular graft applications. In this study, a bioactive polyurethaneurea has been synthesized by incorporating GGGYIGSRGGGK peptide sequences into the polymer backbone. Successful incorporation of the peptides was confirmed by NMR, contact angle measurement and ESCA. Uniform distribution of peptides on the surface was observed using a fluorescent probe capable of reacting with tyrosine residues on the peptides. Hard segment domains were visualized using tapping mode AFM. Endothelial cell adhesion, spreading, proliferation, migration and extra-cellular matrix production were improved on bioactive polyurethaneurea compared to control polyurethaneurea. Competitive inhibition of endothelial cell attachment and spreading by soluble YIGSR peptides indicated that cell adhesion and spreading were specifically mediated by YIGSR-sensitive cell adhesion receptor, not just by changed surface properties. There was no significant difference in the number of adherent platelets. Therefore, this bioactive polyurethanurea may improve vascular graft endothelialization without increasing thrombogenicity.

Modification of polyurethaneurea with PEG and YIGSR peptide to enhance endothelialization without platelet adhesion

“…These results were a little different from a previous study; introduction of the peptide sequences lowered T g without affecting T m . 6 In this study, the entanglement of the flexible PEG chain and the peptide sequences might affect thermal behavior; the high molecular weight PEG seems to prevent decrease of T g but long peptide sequences also might restrict the crystallization of PEG.…”

“…The incorporation of the PEG as a soft segment did not affect FTIR spectra compared to PUUPPD. 6 For both PUUPPD-PEG and PUUYIGSR-PEG, peaks for hard segments were observed at 1640 cm Ϫ1 (hydrogenbonded urea carbonyl), at 1720 cm Ϫ1 (urethane carbonyl peaks for hydrogen bond), and at 1740 cm Ϫ1 (urethane carbonyl peaks for free bond). The CH stretch peaks of the soft segment, PTMO, appeared at 2850 and 2940 cm Ϫ1 , and the hydrogen-bonded NH peak also appeared at 3310 cm Ϫ1 .…”

“…6 The characteristic proton peaks of tyrosine (6.5-7.0 ppm) from the GGGYIG-SRGGGK sequence were assigned, indicating the successful incorporation of the peptide sequence into the PUUYIGSR polymer. The peaks of prepolymer, PUUPPD-PEG, and PUUYIGSR-PEG were also assigned and characterized.…”

“…The CH stretch peaks of the soft segment, PTMO, appeared at 2850 and 2940 cm Ϫ1 , and the hydrogen-bonded NH peak also appeared at 3310 cm Ϫ1 . 6,21,22 Thermal behaviors from DSC indicate successful incorporation of PEG as a soft segment. The glass transition temperature (T g ) of PUUPPD was observed at 9°C.…”

“…Modifications of biomaterials with adhesive peptide sequences such as YIGSR have shown improved attachment, spreading, and resistance of endothelial cells against shear stress. [3][4][5][6] In a previous study, 6 we synthesized a bioactive polyurethaneurea by incorporating GGGYIG-SRGGGK peptide sequences into the polymer backbone. Improved endothelial cell adhesion, proliferation, migration, and extracellular matrix production were observed.…”