Many membraneless organelles, or biological condensates, that play key
roles in signal sensing and transcriptional regulation form through
phase separation. While the functional importance of these condensates
has inspired many studies to characterize their stability and spatial
organization, the underlying principles that dictate these emergent
properties are still being uncovered. In this review, we examine recent
work on biological condensates, especially multicomponent systems. We
focus on connecting molecular factors such as binding energy, valency,
and stoichiometry with the interfacial tension, explaining the
nontrivial interior organization in many condensates. We further discuss
mechanisms that arrest condensate coalescence by lowering the surface
tension or introducing kinetic barriers to stabilize the multidroplet
state.