posted on 2022-12-27, 17:04authored byJasmin Baron, Lena Bauernhofer, Sean R. A. Devenish, Sebastian Fiedler, Alison Ilsley, Sabrina Riedl, Dagmar Zweytick, David Glueck, Ariane Pessentheiner, Grégory Durand, Sandro Keller
Microfluidic diffusional
sizing (MDS) is a recent and
powerful
method for determining the hydrodynamic sizes and interactions of
biomolecules and nanoparticles. A major benefit of MDS is that it
can report the size of a fluorescently labeled target even in mixtures
with complex, unpurified samples. However, a limitation of MDS is
that the target itself has to be purified and covalently labeled with
a fluorescent dye. Such covalent labeling is not suitable for crude
extracts such as native nanodiscs directly obtained from cellular
membranes. In this study, we introduce fluorescent universal lipid
labeling for MDS (FULL-MDS) as a sparse, noncovalent labeling method
for determining particle size. We first demonstrate that the inexpensive
and well-characterized fluorophore, Nile blue, spontaneously partitions
into lipid nanoparticles without disrupting their structure. We then
highlight the key advantage of FULL-MDS by showing that it yields
robust size information on lipid nanoparticles in crude cell extracts
that are not amenable to other sizing methods. Furthermore, even for
synthetic nanodiscs, FULL-MDS is faster, cheaper, and simpler than
existing labeling schemes.