Biomimetic Membranes for Multi-Redox Center Proteins

Abstract

His-tag technology was applied for biosensing purposes involving multi-redox center proteins (MRPs). An overview is presented on various surfaces ranging from flat to spherical and modified with linker molecules with nitrile-tri-acetic acid (NTA) terminal groups to bind his-tagged proteins in a strict orientation. The bound proteins are submitted to in situ dialysis in the presence of lipid micelles to form a so-called protein-tethered bilayer lipid membrane (ptBLM). MRPs, such as the cytochrome c oxidase (CcO) from R. sphaeroides and P. denitrificans, as well as photosynthetic reactions centers (RCs) from R. sphaeroides, were thus investigated. Electrochemical and surface-sensitive optical techniques, such as surface plasmon resonance, surface plasmon-enhanced fluorescence, surface-enhanced infrared absorption spectroscopy (SEIRAS) and surface-enhanced resonance Raman spectroscopy (SERRS), were employed in the case of the ptBLM structure on flat surfaces. Spherical particles ranging from µm size agarose gel beads to nm size nanoparticles modified in a similar fashion were called proteo-lipobeads (PLBs). The particles were investigated by laser-scanning confocal fluorescence microscopy (LSM) and UV/Vis spectroscopy. Electron and proton transfer through the proteins were demonstrated to take place, which was strongly affected by the membrane potential. MRPs can thus be used for biosensing purposes under quasi-physiological conditions.

Boosting biomolecular interactions through DNA origami nano-tailored biosensing interfaces

“…To improve the interaction between target and surface-based bioreceptors, research has been devoted to control the surface functionalization with respect to orientation and packing density of the bioreceptors, as well as the geometry and dimensions of the sensing surface. The effects of strategies such as backfilling [5][6][7] , self-assembled monolayers [8][9][10] and the use of inorganic nanostructures [11][12][13] have been demonstrated, all resulting in increased target interaction. These strategies are, amongst other reasons, used to reduce steric hindrance and enhance the upright orientation of the bioreceptors on the biosensor surface, hereby improving their overall accessibility.…”