Optimizing the bio-affinity interaction between His-tag proteins and Ni(II) surface sites

Protein at interfaces III. State of the art.

American Chemical Society

Año: 2012; p. 37 - 53

The bioaffinity interaction between Histidine (His)-tag proteins and Ni(II) surface sites is exploited as a biofunctionalization strategy to achieve a better surface bioactivity than that provided by physical adsorption. This improved functioning is mainly ascribed to the presence of site-oriented proteins on the surface, induced by the interaction between the tag and the Ni(II) sites. In addition to the induced bioaffinity interaction, His-tag proteins are also spontaneously adsorbed (through hydrophobic and electrostatic interactions) on the substrate. These physically adsorbed proteins are randomly oriented and less bioactive, lowering the surface biorecognition capabilities. Therefore, the surface biofunctionalization based on His-Ni(II) interaction requires the optimization of the experimental conditions to promote the bioaffinity interaction while minimizing physical adsorption. This optimization can be achieved by properly selecting the adsorption conditions (solution pH and ionic strength, protein surface coverage, etc.) and the washing agents prior to the detection of the biorecognition event. This chapter is aimed at discussing experimental results related to the optimization of the bioaffinity interaction between a particular recombinant His-tag antigen and Ni(II) surface sites.