new Zetasizer µV is an advanced light scattering system specifically intended
for the characterization of proteins and other biomolecules. This latest addition
to Malvern’s highly successful Zetasizer family, is designed and optimised
for maximum sensitivity and minimum sample volume. The Zetasizer µV is
a dedicated system that supports improved understanding and management of a
wide range of biomolecule applications, including: optimising sample and storage
conditions; verifying the quaternary structure of protein complexes; identifying
thermal characteristics; and assessing protein solubility and sample purity.
The amount of protein available, particularly during early stages of discovery
is often very limited, so the ability to measure very small quantities is critical.
The Zetasizer µV requires just two microlitres of sample, allowing measurement
of as little as 40 picograms of BSA (bovine serum albumin) for example –
an industry leading specification. Sample is recoverable, ensuring no loss of
valuable material. The use of SOP’s (standard Operating procedures) means
that the measurements proceed with no user input and are managed and supported
by the proven software used throughout the Zetasizer range.
The Zetasizer µV employs both dynamic (DLS) and static light scattering
(SLS). DLS determines the diffusion speed of proteins and nanoparticles in solution
to give accurate measurement of size and size distribution. SLS enables determination
of absolute molecular weight and 2nd virial coefficient, a parameter used to
assess protein solubility and suitable conditions for crystallisation.
However, the real value of the Zetasizer µV lies in using the measured
properties to help solve application problems. In bioprocessing, for example,
it can be used to investigate the effects of changing environmental factors
on the monomeric or oligomeric state of a protein. In drug target development,
dynamic and static light scattering in combination can help in optimising crystallization
conditions, speeding up the development process. In protein therapeutics, where
the presence of aggregates can cause adverse effects, DLS provides an extremely
sensitive method for aggregate detection, improving the success of a purification
procedure or providing a tool for monitoring the early stages of instability.