Dynamic light scattering (DLS) is a technique used to measure the size of small particles in a solution. It works by shining a laser light on the sample, which causes the particles to scatter the light. The scattered light fluctuates in intensity due to the movement of the particles, and these fluctuations can be analyzed to determine the size and distribution of the particles, typically in the nanometer range. DLS is commonly used in various fields, including biotechnology, pharmaceuticals, and materials science. It helps researchers understand the properties of colloids, proteins, and nanoparticles, providing valuable information for applications such as drug formulation and quality control.