Original article: https://doi.org/10.1371/journal.pone.0312594
Surface Plasmon Resonance (SPR) is a technique usually used to study how two molecules interact—one is fixed to a gold surface, and the other flows over it inside a small channel. Normally, during these experiments, effects like mixing and molecule movement (called convection and diffusion) are reduced as much as possible. This helps get accurate measurements of how fast and strongly the molecules bind to each other.
However, in this study, SPR is used in a completely new way. For the first time, a commercial SPR device was used not to study interactions, but instead to measure how quickly molecules move (diffuse) in a solution—a property known as the diffusion coefficient (D).
The researchers created a special setup using the SPR equipment to accurately measure this diffusion. They showed that their method is very precise, reliable, and can be used for many different types of molecules and biomolecules.
This new approach expands how SPR can be used—not just for studying binding between molecules, but also for measuring important physical properties like diffusion.