Personne : Laroche, Gaétan
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Laroche
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Gaétan
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Université Laval. Département de génie des mines, de la métallurgie et des matériaux
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ncf10316941
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Publication Accès libre Fibronectin grafting to enhance skin sealing around transcutaneous titanium implant(John Wiley & Sons, 2021-04-30) Bilem, Ibrahim; Ghadhab, Souhaila; Ruel, Jean; Laroche, Gaétan; Auger, François A.; Guay-Bégin, Andrée-Anne; Pauthe, Emmanuel; Chevallier, PascaleIntraosseous transcutaneous amputation prosthesis is a new approach in orthopedic implants that overcomes socket prosthesis problems. Its long-term performance requires a tight skin-implant seal to prevent infections. In this study, fibronectin (Fn), a widely used adhesion protein, was adsorbed or grafted onto titanium alloy. Fn grafting was performed using two different linking arms, dopamine/glutaric anhydride or phosphonate. The characterization of Fn-modified surfaces showed that Fn grating via phosphonate has led to the highest amount of Fn cell-binding site (RGD, arginine, glycine, and aspartate) available on the surface. Interestingly, cell culture studies revealed a strong correlation between the amount of available RGD ligands and cellular behavior, since enhanced proliferation and spreading of fibroblasts were noticed on Fn-grafted surfaces via phosphonate. In addition, an original in vitro mechanical test, inspired from the real situation, to better predict clinical outcomes after implant insertion, has been developed. Tensile test data showed that the adhesion strength of a bio-engineered dermal tissue was significantly higher around Fn-grafted surfaces via phosphonate, as compared to untreated surfaces. This study sheds light on the importance of an appropriate selection of the linking arm to tightly control the spatial conformation of biomolecules on the material surface, and consequently cell interactions at the interface tissue/implant.Publication Accès libre Grafting of a model protein on lactide and caprolactone based biodegradable films for biomedical applications(Taylor & Francis, 2014-01-23) Larrañaga, Aitor; Laroche, Gaétan; Guay-Bégin, Andrée-Anne; Chevallier, Pascale; Sabbatier, Gad; Fernández, Jorge; Sarasua, José-RamónThermoplastic biodegradable polymers displaying elastomeric behavior and mechanical consistency are greatly appreciated for the regeneration of soft tissues and for various medical devices. However, while the selection of a suitable base material is determined by mechanical and biodegradation considerations, it is the surface properties of the biomaterial that are responsible for the biological response. In order to improve the interaction with cells and modulate their behavior, biologically active molecules can be incorporated onto the surface of the material. With this aim, the surface of a lactide and caprolactone based biodegradable elastomeric terpolymer was modified in two stages. First, the biodegradable polymer surface was aminated by atmospheric pressure plasma treatment and second a crosslinker was grafted in order to covalently bind the biomolecule. In this study, albumin was used as a model protein. According to X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), albumin was efficiently immobilized on the surface of the terpolymer, the degree of albumin surface coverage (ΓBSA) reached ~35%. Moreover, gel permeation chromatography (GPC) studies showed that the hydrolytic degradation kinetic of the synthesized polymer was slightly delayed when albumin was grafted. However, the degradation process in the bulk of the material was unaffected, as demonstrated by Fourier transform infrared (FTIR) analyses. Furthermore, XPS analyses showed that the protein was still present on the surface after 28 days of degradation, meaning that the surface modification was stable, and that there had been enough time for the biological environment to interact with the modified material.Publication Accès libre Effect of linking arm hydrophilic/hydrophobic nature, length and end-group on the conformation and the RGD accessibility of surface-immobilized fibronectin(Elsevier, 2019-10-30) Laroche, Gaétan; Vanslambrouck, Stéphanie; Guay-Bégin, Andrée-Anne; Chevallier, PascaleIn order to stimulate the cellular response to implant materials, extracellular matrix (ECM) proteins, such as collagen and fibronectin (FN), are immobilized on the implant surface. Amongst all ECM proteins used for biomimetic materials for medical applications, FN is one of the most investigated proteins thanks to its ability to promote cell adhesion and its contribution to important physiological processes. However, its conformation and hence its bioactivity strongly depend on the hydrophilic/hydrophobic nature of the surface as well as on immobilization strategies. This work investigates the effect of these two parameters, as well as the effect of the crosslinker length. FN was grafted onto silicon wafers using eights different linking arms presenting different lengths, hydrophilic/hydrophobic characters and binding sites. The protein was linked through either its amino groups (lysine amino acids) or sulfhydryl functionalities (cysteine amino acids). The grafting of each crosslinker and subsequent FN conjugation onto the surfaces was evidenced by X-ray photoelectron spectroscopy, while the surface hydrophilicity was determined by contact angle measurements. Moreover, atomic force microscopy images revealed that the conformation of surface conjugated FN only depends on the hydrophilicity of the linking arm. The FN conformation was also probed by enzyme-linked immunosorbent assays (ELISA). ELISA data demonstrated that all of the three investigated parameters linking arm parameter (length, hydrophobic/hydrophilic character, and terminal end-group) somewhat influence the RGD accessibility.