Magnetically levitating proteins to precisely measure their density

The density of proteins in solution is an important fundamental biophysical quantity that has not been accurately measured yet. This has led to extensive debate in the literature regarding the precise density value of proteins. This rough density metric can often lead to inaccurate estimates on the other physicochemical and composite protein features, especially after their interactions with other materials such as nanoparticles. Researchers have now demonstrated a new technique using superparamagnetic iron oxide nanoparticles for magnetic levitation, which promises a more precisely measurement of the density of proteins in solution.