Surface Characteristics Control the Attachment and Functionality of (Chimeric) Avidin

Abstract

The physical adsorption (physisorption) of proteins to surfaces is an important but incompletely understood factor in many biological processes and is of increasing significance in bionanotechnology as well. Avidin is an important protein because of strong avidin–biotin binding, which has been exploited in numerous applications. We have undertaken thorough experimentation on the physisorption of avidin, to chemically different flat surfaces of Si and graphite and also to the curved version of the latter, on multiwalled carbon nanotubes (MWNTs) of different diameters. The difference in the behavior of avidin on Si versus graphite is drastic; on Si, avidin deposits as single globular tetrameric units and maintains functionality, whereas on graphite, it forms irregular networks of two-layer thick filaments, where the first layer has lost its biological activity. On MWNTs, avidin also deposits as one-dimensional formations, or stripes, but these appear to order in a perpendicular arrangement to the MWNT axis. A better understanding of protein–surface interactions is essential for the development of robust and reliable methods for biofunctionalization of materials. This work also provides insights into the importance of the nanoscale surface architecture.

Avidin-Conjugated Nanofibrillar Cellulose Hydrogel Functionalized with Biotinylated Fibronectin and Vitronectin Promotes 3D Culture of Fibroblasts

“…However, generally dry samples appear smaller (height and width) on AFM analysis compared to the native wet samples due to dehydration. Indeed, using AFM, Shao et al reported that after drying with nitrogen gas, the height of the avidin tetramer was about 2.5–3 nm on the silicon surface, and our findings are well in line with that. All samples showed some height variation within single fibrils, which may be attributed to intrinsic structure of the fibrils, such as twisting.…”

Thiol‐Click Based Polyglycerol Hydrogels as Biosensing Platform with In Situ Encapsulated Streptavidin Probes

“…Gel AL2, on the other hand, shows slowest release with less than 40% even after 11 days, despite the fact that it has the lowest storage modulus (Figure 2) (or biggest mesh size [Figure S7, Supporting Information]) among them. The reason could come from the London dispersion interaction [54] between the large hydrophobic surface of a streptavidin [55,56] and thiol-allyl crosslinking region which is also hydrophobic, resulting in stable immobilization of streptavidin and slower release. It should be noted that besides the physical network density, the chemistry of the functional groups also has a great influence on the release, as it can be basically degradable or non-degradable.…”

Impact of Tether Length and Flexibility on the Efficiency of Analyte Capture by Tethered Receptors

“…[46] It has been demonstrated that passive surface adsorption of Neutravidin leads to protein alteration in terms of conformation and aggregation (multilayers) which may alter the interface outcome, and that can be overcome by the use of PEG tethers. [47,48] Teramura et al have pointed to the possibility of enhancing avidin density by increasing molar mass of PEG tethers, when the density of tethered biotin is conserved. [49] However, the study does not take into account the viscoelastic effects during the QCM measurements that could result in overestimation in PEG mass per surface area at molar mass above 5000 g/mol.…”