Binding and release of basic fibroblast growth factor from heparinized collagen matrices

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Vascular Surgery

Background:

• Endothelial cell seeding enhances small-diameter vascular graft performance.
• Basic fibroblast growth factor (bFGF) accelerates endothelial cell growth on grafts.
• Effective matrices are needed for sustained bFGF release and cell adhesion.

Purpose of the Study:

• To evaluate two collagen-based matrices for in vivo endothelial cell seeding.
• To assess bFGF binding and release characteristics of EDC/NHS-crosslinked collagen and heparinized versions.
• To determine the optimal matrix for pre-loading bFGF for vascular graft applications.

Main Methods:

• Collagen matrices crosslinked with EDC/NHS were prepared.
• Varying amounts of heparin were immobilized onto crosslinked collagen (E/N14C) using EDC/NHS.
• bFGF binding capacity and sustained release kinetics were quantified for both non-heparinized (E/N14C) and heparinized (E/N14C-H(0.4)) matrices.

Main Results:

• Heparinized E/N14C-H(0.4) showed significantly higher bFGF binding (22%) compared to E/N14C (10%).
• E/N14C-H(0.4) exhibited a sustained bFGF release profile with only 2% burst release in 6 hours, versus 30% for E/N14C.
• After 28 days, E/N14C-H(0.4) retained 65% of bFGF, while E/N14C released 100%.

Conclusions:

• Heparin immobilization on EDC/NHS-crosslinked collagen significantly enhances bFGF binding.
• The heparinized matrix (E/N14C-H(0.4)) provides superior sustained release of bFGF.
• E/N14C-H(0.4) is the preferred substrate for pre-loading bFGF for endothelial cell seeding on vascular grafts.