In Situ Dynamic Light Scattering Complementing Neutron Spin Echo Measurements on Protein Samples

Monitoring the state of the sample on the minute-time scale is crucial in case of sensitive soft matter or biological samples, given that neutron spin echo measurements take up to several days. Moreover, there is no method to interpret the normalized intermediate scattering function obtained by measuring the neutron spin echo if relevant sample properties change during measurement. Dynamic light scattering provides information on the diffusion constant of particles in solution (biological macromolecules, such as proteins, protein aggregates, polymer particles, etc.) with average hydrodynamic radii in a wide range from several nanometers up to several microns. This information can be obtained in a few minutes and it offers a good overview of the current sample state. Details on the novel in situ dynamic light scattering set-up with one fixed scattering angle and first results obtained on a molten globule state of apo-myoglobin are presented.