We describe the preparation and properties of lipodisc nanoparticles – lipid membrane fragments
with a diameter of about 10 nm, stabilized by amphiphilic synthetic polymer molecules. We used the lipodisc
nanoparticles made of Escherichia coli polar lipids and compared lipodisc nanoparticles that contained the
photosensitive protein complex of the sensory rhodopsin with its cognate transducer from the halobacterium
Natronomonas pharaonis with empty lipodisc nanoparticles that contained no protein. The lipodisc nanoparticles were characterized by dynamic light scattering, transmission electron microscopy and atomic force
microscopy. We found that the diameter of lipodisc nanoparticles was not affected by incorporation of the
protein complexes, which makes them a prospective platform for single-molecule studies of membrane proteins.