Wyatt has published a paper on its Dynapro Plate Reader dynamic light scattering (DLS) instrument for achieving rapid detection and characterisation of protein aggregates.
The Dynapro Plate Reader performed DLS measurements on samples within the wells of a well plate without removing the samples or physically introducing any substances into the wells.
As a result, this instrument was able to allow for programmed measurements of many solution conditions with minimum user intervention.
Protein systems often exhibit aggregation as a result of changes in environmental conditions, including changes in formulation pH, ionic strength, concentration, series of freeze-thaw cycles and forced aging.
Aggregation of proteins is closely related to and may even cause several neurodegenerative disorders in humans such as Alzheimer's, Parkinson's, Huntington's disease, amyotrophic lateral sclerosis and prion diseases.
DLS determines the specific conditions that lead to aggregation and can perform fast and accurate measurements of multiple samples, clearly establishing aggregation conditions.
An experiment demonstrated the analytical capabilities of DLS.
For this particular application, protein samples with varying degrees of aggregation were generated by heat stressing Bovine Serum Albumin (BSA) at 60C.
Aliquots were removed from the solution every five minutes for 175 minutes.
Proteins were expected to exhibit increased aggregation with increased time held at 60C.
Triplicate 30 uL aliquots of each condition were placed into a low volume 384 well plate, resulting in 108 aliquots for the 36 different exposure times.
Following sample collection and plate loading, the plate was placed into a Wyatt Dynapro DLS Plate Reader with the sample space held at 5C.
The plate was then stored for 13 days at 5C and re-measured at 5C.
The total measurement time for the plate was only 50 minutes, including movement between wells and auto-adjustment of laser power and detector attenuation settings.
The results demonstrated the average size of the samples in solution increase with exposure time, resulting in longer correlation times.
The increased hydrodynamic radius and intensity of scattered light indicated increased aggregation of proteins with increased exposure to 60C.
Aggregation was not found to evolve significantly over two week's storage at 5C.
