title: Multilayer vascular grafts based on collagen-mimetic proteins.
abstract: A major roadblock in the development of an off-the-shelf, small-caliber vascular graft is achieving rapid endothelialization of the conduit while minimizing the risk of thrombosis, intimal hyperplasia, and mechanical failure. To address this need, a collagen-mimetic protein derived from group A Streptococcus, Scl2.28 (Scl2), was conjugated into a poly(ethylene glycol) (PEG) hydrogel to generate bioactive hydrogels that bind to endothelial cells (ECs) and resist platelet adhesion. The PEG-Scl2 hydrogel was then reinforced with an electrospun polyurethane mesh to achieve suitable biomechanical properties. In the current study, initial evaluation of this multilayer design as a potential off-the-shelf graft was conducted. First, electrospinning parameters were varied to achieve composite burst pressure, compliance, and suture retention strength that matched reported values of saphenous vein autografts. Composite stability following drying, sterilization, and physiological conditioning under pulsatile flow was then demonstrated. Scl2 bioactivity was also maintained after drying and sterilization as indicated by EC adhesion and spreading. Evaluation of platelet adhesion, aggregation, and activation indicated that PEG-Scl2 hydrogels had minimal platelet interactions and thus appear to provide a thromboresistant blood contacting layer. Finally, evaluation of EC migration speed demonstrated that PEG-Scl2 hydrogels promoted higher migration speeds than PEG-collagen analogs and that migration speed was readily tuned by altering protein concentration. Collectively, these results indicate that this multilayer design warrants further investigation and may have the potential to improve on current synthetic options.
authors.affiliation: Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843-3120, USA.
authors.forename: M B
authors.initials: MB
authors.lastname: Browning
authors.forename: D
authors.initials: D
authors.lastname: Dempsey
authors.forename: V
authors.initials: V
authors.lastname: Guiza
authors.forename: S
authors.initials: S
authors.lastname: Becerra
authors.forename: J
authors.initials: J
authors.lastname: Rivera
authors.forename: B
authors.initials: B
authors.lastname: Russell
authors.forename: M
authors.initials: M
authors.lastname: Höök
authors.forename: F
authors.initials: F
authors.lastname: Clubb
authors.forename: M
authors.initials: M
authors.lastname: Miller
authors.forename: T
authors.initials: T
authors.lastname: Fossum
authors.forename: J F
authors.initials: JF
authors.lastname: Dong
authors.forename: A L
authors.initials: AL
authors.lastname: Bergeron
authors.forename: M
authors.initials: M
authors.lastname: Hahn
authors.forename: E
authors.initials: E
authors.lastname: Cosgriff-Hernandez
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry*; D040761:Biomimetic Materials / Q000737:chemistry*; D001792:Blood Platelets / Q000166:cytology / Q000378:metabolism; D001807:Blood Vessel Prosthesis; D002448:Cell Adhesion; D002465:Cell Movement; D002478:Cells, Cultured; D003094:Collagen / Q000737:chemistry*; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism; D006801:Humans; D020100:Hydrogels / Q000737:chemistry*; D008422:Materials Testing; D010973:Platelet Adhesiveness; D011092:Polyethylene Glycols / Q000737:chemistry*; D051381:Rats; D012501:Saphenous Vein / Q000737:chemistry; D013291:Streptococcus / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D020100:Hydrogels; C423453:Scl2 protein, Streptococcus; D011092:Polyethylene Glycols; D003094:Collagen