Influence of bioactive linker molecules on protein adsorption

When protein coatings are used in surgical implants, for sensors or in food applications, it is important to be aware of the influence of the immobilization method onto the protein-coating performance. In this manuscript, we report on the effect of several bioactive linker molecules on a protein immobilized on a TiO2 surface. Particularly, the protein adsorption, orientation and functionality, which are directly related to the tertiary structure of the molecule, were investigated. The protein horseradish peroxidase was immobilized on a TiO2 substrate via a range of linker molecules for biomolecule attachment. The chosen linkers can immobilize the proteins in a random fashion via free NH2-groups or COOH-groups. Protein coverage was quantified with XPS, while Time-of-flight secondary ion mass spectrometry (ToF-SIMS) provided information about protein orientation as well as changes in the tertiary structure in relation to the respective linker system. Copyright (c) 2014 John Wiley & Sons, Ltd.