Bioactive micropatterning of biomaterials for induction of endothelial progenitor cell differentiation: Acceleration of in situ endothelialization

Abstract

Synthetic grafts do not provide an appealing surface for endothelial cells to adhere and colonize the inner surface. To promote in situ endothelialization the following aspect has to be taken into account, endothelial progenitor cells (EPCs) needs to be mobilized on the surface of the graft. The surface of the graft has to be sufficiently biocompatible to create a prone environment for the EPCs to adhere, proliferate and, differentiate to form a layer and subsequently improve graft patency. In this work, two active molecules GRGDS and sitagliptin, were chosen for their abilities to recruit, enhance adhesion and induce differentiation of endothelial progenitor cells. They were grafted on PET surfaces in order to provide restrained cues triggering cell alignment and evaluate the influence of such structuration on EPCs fate. We then analyze cell behavior onto functionalized biomaterials. Their abilities to control EPCs fate were demonstrated via RT-qPCR, immunofluorescence, and enzymatic tests. The GRGDS/sitagliptin 100 × 10 surface enables to reduce the stemness phenotype on EPCs and induce the expression of endothelial lineage markers. These results highlight the importance of spatial patterning cues in guiding EPCs organization and function, which may have clinical relevance in the development of vascular grafts that promote patency. K E Y W O R D S endothelial progenitor cells, endothelialization, in situ differentiation, peptides grafting, surface functionalization

Peptide grafting on intraosseous transcutaneous amputation prostheses to promote sealing with skin cells: Potential to limit infections

“…However, in this case, it turned out that, as pointed out by the supplier, the thiourea link between the fluorophore and the peptide may deteriorate over time with, on top of that, a lesser stability of the labeling molecule at the pH of the tween solution. Accordingly, the measured KRGDS surface concentration was found to be one tenth of those measured in previous studies with similar grafting procedures without tween washing 33–36 (results not shown). Accordingly, the fluorescence image of the KRGDS‐FITC grafted surface is presented only for sake of showing the homogeneity of the surface conjugation but cannot be used to ascertain the peptide surface concentration.…”

“…Accordingly, the measured KRGDS surface concentration was found to be one tenth of those measured in previous studies with similar grafting procedures without tween washing [33][34][35][36] (results not shown). Accordingly, the fluorescence image of the KRGDS-FITC grafted surface is presented only for sake of showing the homogeneity of the surface conjugation but cannot be used to ascertain the peptide surface concentration.…”

“…As aforementioned, such a quantification was not possible for KRGDS-FITC due to the deterioration of the peptide-fluorophore link over time and a decreased stability of the fluorophore itself at pH close to that of the tween solutions. Previous studies made in our group point toward a KRGDS concentration ranging between 0.5 and 2 peptide molecules/nm 2 [33][34][35][36]. In addition, the measurement of the KRGDS-FITC surface concentration before rincing with tween also led to a value of 1.5 molecule/nm 2 .…”

Controlling differentiation of stem cells via bioactive disordered cues

“…The absorbance of desorbed dyes in the solution allowed us to assess surface carboxyl group density on the PET surface. 63 COOH densities obtained for PET, PET-activated, PET-BMP and PET-RGD samples are 30 ± 7 pmol mm −2 (∼18 COOH per nm 2 ), 20 ± 8 pmol mm −2 (∼12 COOH per mm 2 ), 13 ± 0 pmol mm −2 (∼8 COOH per mm 2 ) and 17 ± 7 pmol mm −2 (∼10 COOH per nm 2 ), respectively.…”

“…This result is consistent with previous publications (C = 71.0 at%, O = 27.0 at%, C/O = 2.6). 36,63 A slight contamination of nitrogen (N = 0.1 at%) was detected on the PET surface. As reported by Fang et al, the components of PET mainly exist in C-C/C-H (284.8 eV), C-O (286.4 eV), and O-CvO (288.8 eV) bonding.…”