Bioactivation of porous polyurethane scaffolds using fluorinated RGD surface modifiers

Biomaterial scaffolds for tissue engineering require appropriate cell adhesion, proliferation, and infiltration into their three-dimensional (3D) porous structures. Surface modification techniques have the potential to enhance cell infiltration into synthetic scaffolds while retaining bulk material properties intact. The objective of this work was to assess the potential of achieving a uniform surface modification in 3D porous constructs through the blending of surface-modifying additives known as bioactive fluorinated surface modifiers (BFSMs) with a base polyurethane material. By coupling RGD peptides to the fluorinated surface modifiers to form RGD-BFSMs, the BFSMs can act as a vehicle for the delivery of RGD moieties to the surface without direct covalent attachment to the polymer substrate. Fluorescent RGD-BFSMs were shown to migrate to the polymer-air interfaces within the porous scaffolds by two-photon confocal microscopy. A-10 rat aortic smooth muscle cells were cultured for 4 weeks on nonmodified and RGD-BFSM-modified porous scaffolds, and cell adhesion, proliferation, and viability were quantified at different depths. RGD-BFSM-modified scaffolds showed significantly greater cell numbers within deeper regions of the scaffolds, and this difference became more pronounced over time. This study demonstrates an effective approach to promote cell adhesion and infiltration within thick (approximately 0.5 cm) porous synthetic scaffolds by providing a uniform distribution of adhesive peptide throughout the scaffolds without the use of covalent surface reaction chemistry.