Surface coverage dictates the surface bio-activity of D-amino acid oxidase.

This work presents a systematic study on the relationship between the adsorption mechanism and the surface bio-activity of D-amino acid oxidase (pkDAAO). This rational approach is based on measuring the characteristic filling and relaxation times under different experimental conditions. With such a goal, real-time adsorption-desorption experiments at different degrees of surface coverage were performed tuning the electrostatic and hydrophobic interactions by changing the pH condition for the adsorption and the substrate properties (silica or gold).

Ni(ii)-modified solid substrates as a platform to adsorb His-tag proteins.

This work investigated a simple and versatile modification to a solid substrate to develop electrochemical bio-recognition platforms based on bio-affinity interactions between histidine (His)-tagged proteins and Ni(ii) surface sites. Carboxylate (COO)-functionalized substrates were prepared in multiple steps, initiated with an amino-terminated self-assembled monolayer (SAM) on polycrystalline gold. Surface enhanced Raman spectroscopy (SERS), quartz crystal microbalance with dissipation monitoring (QCM-D) and contact angle measurements were used to follow the modification process.