Formation and cross-linking of fibrinogen layers monitored with in situ spectroscopic ellipsometry

Thick matrices of fibrinogen with incorporation of a matrix metalloproteinase inhibitor were covalently bonded on functionalized silicon surfaces using an ethyl-3-dimethyl-aminopropyl-carbodiimide and N-hydroxy-succinimide affinity ligand coupling chemistry. The growth of the structure was followed in situ using dynamic ellipsometry and characterized at steady-state with spectroscopic ellipsometry. The growth was compared with earlier work on ex situ growth of fibrinogen layers studied by single wavelength ellipsometry. It is found that in situ growth and ex situ growth yield different structural properties of the formed protein matrix. Fibrinogen matrices with thicknesses up to 58 nm and surface mass densities of 1.6 μg/cm² have been produced.