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Kinesin motor proteins play an important role in intracellular transport by moving different types of cargo such as
vesicles and filaments along microtubule tracks in living cells. The principles behind single kinesin intracellular
transport are well known; however, little is known about collective kinesin behavior. In particular, we predict that
kinesin motor proteins will behave differently when attached to cargo with a rigid vs. a fluid membrane. To better
understand kinesin behavior when interacting with fluid membranes, biomimetic sunflower oil droplets were created
with two surfactant types (ceramide-PEG(2000) and biotinylated DSPE-PEG(2000)). The ratio of the two
surfactants determines how many kinesins can bind to the droplets through a biotin-streptavidin-biotin linkage.
Equilibrium interfacial tension was measured using an optical tensiometer for different concentrations and different
ratios of the two surfactants. The kinesin surface coverage was calculated from the equilibrium interfacial tension
and the ratio of biotinylated surfactants. Based on the calculated surface coverage of kinesin motor proteins, we can
control the number of kinesins present on each biomimetic sunflower oil droplet by manipulating the concentrations
and ratio of the two different surfactants. Once the biomimetic sunflower oil droplets are optimized to attach the
desired number of kinesins, tests can be performed using an optical trap to determine the kinesin behavior when
pulling the fluid membrane droplets.