Attachment of peptide growth factors to implantable collagen

Ingrowth of fibrovascular tissue from the woundbed into collagen-based dermal substitutes and survival of cultured epithelium after transplantation may be enhanced by attachment of heparin binding growth factor 2 (HBGF2) and epidermal growth factor (EGF) to collagen. Biotinylation of collagen and the growth factors allows immobilization of HBGF2 and EGF by high affinity binding of tetravalent avidin. Biotinylated HBGF2 and EGF (B-GF) were exposed to complexes of biotinylated collagen (B-COL)-avidin (A) and detected with peroxidase-labeled avidin (AP) followed by chromagen formation on nitrocellulose paper. Binding of biotinylated HBGF2 and EGF was specific (∗, P < 0.05), proportional to the concentration of biotinylated collagen, and resistant to ionic (NaCl) displacement. Data are expressed as mean percentages of maximum binding ± SEMs: % Maximum binding Condition HBGF2 EGF (1) B-COL, A, B-GF, AP 95.5 ± 2.3 96.2 ± 5.2 (2) COL, A, B-GF, AP 40.7 ± 2.6∗ 16.7 ± 1.0∗ (3) B-COL, A, GF, AP 19.6 ± 1.7∗ 1.8 ± 0.4∗ (4) B-COL, A, B-GF, P 9.3 ± 0.7∗ 8.4 ± 0.5∗ (5) Condition 1, 0.15 M NaCl 77.1 ± 1.4∗ 58.6 ± 1.8∗ (6) Condition 1, 1.00 M NaCl 79.5 ± 2.8∗ 65.6 ± 4.3∗ Growth response of cultured human epidermal keratinocytes to HBGF2 (population doubling time, PDT = 0.70 population doublings (PD)/day) confirmed the retention of mitogenic activity after biotinylation (PDT = 0.80 PD/day). Specific binding of biotinylated HBGF2, EGF, or other biologically active molecules (antibiotics, NSAIDs) to implantable collagen may provide a mechanism for positive therapeutic modulation of wound healing, including repair of full-thickness skin wounds with cultured cell-collagen composite grafts.