  Many biological systems fold thin sheets of lipid membrane into complex
three-dimensional structures. This microscopic origami is often mediated by the
adsorption and self-assembly of proteins on a membrane. As a model system to
study adsorption-mediated interactions, we study the collective behavior of
micrometric particles adhered to a lipid vesicle. We estimate the colloidal
interactions using a maximum likelihood analysis of particle trajectories. When
the particles are highly wrapped by a tense membrane, we observe strong
long-range attractions with a typical binding energy of 150 $k_B T$ and
significant forces extending a few microns.
