Measurement of rotational diffusion by Fluorescence correlation spectroscopy (FCS) (CAT#: STEM-MB-1101-WXH)

Name: Measurement of rotational diffusion by Fluorescence correlation spectroscopy (FCS)
SKU: STEM-MB-1101-WXH
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Introduction

Rotational diffusion is the rotational movement which acts upon any object such as particles, molecules, atoms when present in a fluid, by random changes in their orientations.
Rotational diffusion has multiple applications in chemistry and physics, and is heavily involved in many biology based fields. For example, protein-protein interaction is a vital step in the communication of biological signals. In order to communicate, the proteins must both come into contact with each other and be facing the appropriate way to interact with each other's binding site, which relies on the proteins ability to rotate.

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Principle Applications Procedure Materials

Principle

Fluorescence correlation spectroscopy (FCS) is a statistical analysis, via time correlation, of stationary fluctuations of the fluorescence intensity. Its theoretical underpinning originated from L. Onsager's regression hypothesis. The analysis provides kinetic parameters of the physical processes underlying the fluctuations. One of the interesting applications of this is an analysis of the concentration fluctuations of fluorescent particles (molecules) in solution. In this application, the fluorescence emitted from a very tiny space in solution containing a small number of fluorescent particles (molecules) is observed. The fluorescence intensity is fluctuating due to Brownian motion of the particles. In other words, the number of the particles in the sub-space defined by the optical system is randomly changing around the average number. The analysis gives the average number of fluorescent particles and average diffusion time, when the particle is passing through the space. Eventually, both the concentration and size of the particle (molecule) are determined. Both parameters are important in biochemical research, biophysics, and chemistry.

Applications

• Measurement of the diffusion coefficient of biomolecules
• Detection of translational diffusions
• Measurement of the biomolecular concentration in vitro or in vivo
• Quantification of the viscosity of a solution
• Monitoring the binding or unbinding of two kinds of biomolecules
• Probing the diffusion paths of different directions and mapping the intercellular obstacles