Peptide Route Functionalization of ZnSe Crystals Preserves Activity and Structure of Proteins while Adsorption

Abstract

Despite the current fast development of materials science, preserving activity and native structure of biomolecules upon their adsorption on a solid substrate is still a challenge in the elaboration of hybrid functional materials. We describe a novel functionalization method of the Zinc Selenide (ZnSe) semiconductor with a peptide presenting surface recognition properties for this material. The peptide was further used as a linker and interface layer when horseradish peroxidase (HRP) was adsorbed onto the ZnSe surface. Our ELISA assays evidenced that HRP activity was enhanced 2-fold when adsorbed on ZnSe via use of the specific peptide compared to when it was directly adsorbed onto the bare surface or the one modified by a polyelectrolyte film. We demonstrate that the secondary structure of the enzyme in its adsorbed form is much closer to its native secondary structure found in solution when peptide functionalization of ZnSe crystal was performed prior to HRP adsorption. The affinity of the peptide for the ZnSe was quantified via force spectroscopy measurements performed with atomic force microscopy and the binding forces between this peptide and the ZnSe were measured to be 125 ± 30 pN. Our results demonstrate the outstanding utility of the specific peptide in surface modification of ZnSe thus avoiding protein denaturation while adsorption. This may be of great interest in triggering biological applications of ZnSe based devices (diodes, attenuated total reflection crystals, prisms, and quantum dots) where interaction with biomolecules is expected.