Real time, high resolution studies of protein adsorption and structure at the solid–liquid interface using dual polarization interferometry

Abstract

A novel method for the analysis of thin biological films, called dual polarization interferometry (DPI), is described. This high resolution (<1 Å), laboratory-based technique allows the thickness and refractive index (density) of biological molecules adsorbing or reacting at the solid–liquid interface to be measured in real time (up to 10 measurements per second). Results from the adsorption of bovine serum albumin (BSA) on to a silicon oxynitride chip surface are presented to demonstrate how time dependent molecular behaviour can be examined using DPI. Mechanistic and structural information relating to the adsorption process is obtained as a function of the solution pH.

α-Synuclein Senses Lipid Packing Defects and Induces Lateral Expansion of Lipids Leading to Membrane Remodeling

“…DPI is a unique technique that makes realtime thickness and refractive index measurements of thin isotropic layers deposited on the top of a sensing waveguide (34,35). In the case of an anisotropic layer, such as a lipid bilayer, the mass and the birefringence can be monitored, providing highly valuable information about the mode of interaction of proteins with lipid membranes by monitoring the changes in lipid ordering (36 -39).…”

Separation of bovine serum albumin (BSA) using γ‐Al2O3–clay composite ultrafiltration membrane

“…43,44 Figure 10 illustrates the variation of BSA flux and rejection with pH for a feed concentration of 0.5 g L −1 at 207 kPa. It is observed from Fig.…”

Simultaneous Measurement of 10,000 Protein-Ligand Affinity Constants Using Microarray-Based Kinetic Constant Assays

“…35 Label-free optical biosensing methods, such as surface plasmon resonance reflectometry (SPR), [36][37][38][39][40][41][42] reflection interference spectroscopy, [43][44][45] dielectric wave guide reflectometry, [46][47][48][49] and imaging ellipsometry, 50-54 complement fluorescence-based detection by doing away with labeling and providing both endpoint and kinetic measurements of binding reactions. However, these biosensors only detect a small number of reactions (no more than a few hundred reactions) at a time and often require special (and costly) sensor surfaces.…”