Tracking Aggregation of Virus-Like Particles Using Dynamic Light Scattering

Start with a cuvette containing a purified, monodisperse suspension of virus-like particles in a buffer.

These particles contain the capsid, the protein shell of a virus, but they lack genetic material, making them non-infectious.

Place the cuvette in a dynamic light scattering (DLS) instrument that has been preheated to a target temperature.

Allow the sample to equilibrate briefly, then begin the measurements.

Heating causes the capsid proteins to denature. This structural change exposes hydrophobic regions that promote particle clustering and aggregation.

DLS directs a laser beam through the suspension and measures fluctuations in the scattered light caused by particle motion.

Smaller particles move faster and produce rapid fluctuations in the scattered light, while larger aggregates move more slowly and cause slower fluctuations.

DLS analyzes these fluctuations at regular intervals to track the particle aggregation in real time.

Create a new size standard operating procedure in the DLS instrument software as detailed in the text protocol. Select the run arrow within the software to open and name a new sample and allow the instrument to reach the temperature equilibrium.

Transfer the VLP suspension to a small volume quartz cuvette, avoid bubbles, and pipette slowly against the wall of the cuvette. After the instrument has reached temperature equilibrium, insert the cuvette into the sample chamber. After waiting 10 seconds for the sample temperature to equilibrate, start the run and simultaneously start a timer.

Stop the timer at the end of the first measurement. Take this time as the first time point. Obtain subsequent time points from the measurement times recorded by the software.