Preparation and use of tethered ligands as biomaterials and tools for cell biology.

The immobilization of biomolecules to various supports has been an important research area for many years. Molecules such as heparin (1,2), as well as various enzymes (3,4), antibodies (5,6), and adhesion ligands (7), have been bound to such supports as silicon or glass, agarose gels, polyethylene oxide (PEO) gels, poly(vinyl alcohol) (PVA) gels, and polymer surfaces. These studies have had important applications in the creation of antithrombogenic surfaces for blood contact, affinity chromatography, and tissue growth and regeneration.

Tethered epidermal growth factor as a paradigm for growth factor-induced stimulation from the solid phase.

We have tethered epidermal growth factor (EGF) to a solid substrate in a manner permitting the factor to retain its biological activity as assessed by both mitogenic and morphological assays. Mouse EGF was covalently coupled to aminosilane-modified glass via star poly(ethylene oxide) (PEO), which allows the ligand to retain significant mobility and active conformation. Tethered EGF was as effective as soluble EGF in eliciting DNA synthesis and cell rounding responses of primary rat hepatocytes under different surface conditions. In contrast, physically adsorbed EGF at comparable surface concentrations showed no activity. Presentation of growth factors in this manner may help to expedite their clinical use by permitting greater control of temporal and spatial availability in the extracellular environment.