Protein interactions with layers of TiO2 nanotube and nanopore arrays: Morphology and surface charge influence

摘要

In the present work we investigate the key factors involved in the interaction of small-sized charged proteins with TiO2 nanostructures, i.e. albumin (negatively charged), histone (positively charged). We examine anodic nanotubes with specific morphology (simultaneous control over diameter and length, e.g. diameter 15, 50 or 100 nm, length 250 nm up to 10 mu m) and nanopores. The nanostructures surface area has a direct influence on the amount of bound protein, nonetheless the protein physical properties as electric charge and size (in relation to nanotopography and biomaterial's electric charge) are crucial too. The highest quantity of adsorbed protein is registered for histone, for 100 nm diameter nanotubes (10 mu m length) while higher values are registered for 15 nm diameter nanotubes when normalizing protein adsorption to nanostructures' surface unit area (evaluated from dye desorption measurements) consistent with theoretical considerations. The proteins presence on the nanostructures is evaluated by XPS and ToF-SIMS; additionally, we qualitatively assess their presence along the nanostructures length by ToF-S1MS depth profiles, with decreasing concentration towards the bottom.