SpectroQ

Imaging and DLS

A combined imaging and DLS device fulfils a double purpose, that increases the application spectrum of a plate hotel system significantly. On one hand, crystal plates can be imaged, but sample quality can also be checked before crystallization due to the DLS capability. However, when samples are intended to be measured via DLS and are visually inspected too, the entire size range, from molecular sizes up to microscopic-sized particles can be covered. This is because DLS has a size detection range from about 1 nm to a couple of µm (depending on the particle density). Therefore DLS covers the region of submicroscopic small but moving particles while a microscope visualizes particles from 1 µm and bigger which are usually not moving anymore. A frequent observation is that proteins exist in a steady state situation of a high molecular aggregate and a monomeric or lower molecular weight state coexist. A microscope/DLS combination reveals this by imaging an amorphous solid phase while DLS monitors the particle sizes in the supernatant. Even the Brownian motion itself can be seen via an imaging system when it is combined with DLS.

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