Self-interaction nanoparticle spectroscopy: a nanoparticle-based protein interaction assay.

Solution conditions conducive to protein crystallization are identified mainly in an empirical manner using screening methods. Measurements of a dilute solution thermodynamic parameter, the osmotic second virial coefficient, have been shown to be useful in guiding this search, yet the measurement of this parameter remains difficult. In this work, a nanoparticle-based assay, self-interaction nanoparticle spectroscopy, is presented as an efficient alternative.