Physico-Chemical Characterization of the Interaction of Red Fluorescent Protein-DsRed With Thin Silica Layers

The Discosoma recombinant red fluorescent (DsRed) protein is the latest member of the family of fluorescent proteins. It holds great promise for applications in biotechnology and cell biology. However, before being used for rational engineering, knowledge on the behavior of DsRed and the underlying mechanisms relating its structural stability and adsorption properties on solid surfaces is highly demanded. The physico-chemical analysis performed in this study reveals that the interaction of DsRed with SiO₂ surfaces does not lead to complete protein denaturation after adsorption and dehydration. Nevertheless, the photoluminescence emission of dehydrated DsRed small droplets was found to be slightly red-shifted, peaking at 590 nm. The measured contact angles of droplets containing different concentration of DsRed proteins determine the interaction as hydrophilic one, however with larger contact angles for larger DsRed concentrations. The DsRed protein behavior is not pH-dependent with respect of the contact angle measurements, in agreement with previously reported studies.