Protein adsorption and covalent bonding to silicon nitride surfaces modified with organo-silanes: Comparison using AFM, angle-resolved XPS and multivariate ToF-SIMS analysis

- Protein immobilization compared for Si3N4 modified with amino- and epoxy-silanes.
- Correlated ToF-SIMS and angle-resolved XPS data yield protein surface coverage.
- Surface coverage is higher and develops faster for adsorption than covalent bonding.
- AFM height vs. surface coverage relations reflect distinct packing and conformation.