Collective behaviour in mixed populations of synthetic protocells is an unexplored area of bottom-up synthetic biology.T he dynamics of am odel protocell community is exploited to modulate the function and higher-order behaviour of mixed populations of bioinorganic protocells in response to ap rocess of artificial phagocytosis.E nzymeloaded silica colloidosomes are spontaneously engulfed by magnetic Pickering emulsion (MPE) droplets containing complementary enzyme substrates to initiate ar ange of processes within the host/guest protocells.Specifically,catalase, lipase,oralkaline phosphatase-filled colloidosomes are used to trigger phagocytosis-induced buoyancy,membrane reconstruction, or hydrogelation, respectively,w ithin the MPE droplets. The results highlight the potential for exploiting surfacecontact interactions between different membrane-bounded droplets to transfer and co-locate discrete chemical packages (artificial organelles) in communities of synthetic protocells.Artificial aqueous microcompartments capable of mimicking biological functions,s uch as encapsulation, selective exchange of chemicals with the environment, and minimal metabolism, are currently under investigation as model protocells in synthetic biology,o rigin-of-life studies,a nd biotechnology. [1][2][3][4][5] Thee xternal membrane of these synthetic microcapsules can be tailored using aw ide range of building blocks,s uch as lipids,p olymers,p rotein-polymer conjugates, and inorganic nanoparticles,t omeet specific criteria. [2] For example,aprotocell model based on the spontaneous assembly of partially hydrophobic silica nanoparticles at the interface of water and oil to form water-in-oil Pickering emulsion droplets with amechanically robust membrane has been recently developed. Thei norganic membrane was crosslinked to produce shell-like micro-compartments (colloidosomes) that could be transferred to water and endowed with biomimetic functions,s uch as in situ gene expression, [6] enzyme-mediated catalysis, [6,7] microcapsule growth and divi-sion, [8] membrane gating, [9] enzyme-directed secretion of an extracellular-like matrix, [10] and energy capture and conversion. [11] Thee mergence of collective behaviour in mixed populations of synthetic protocells is relatively unexplored, even though increasing levels of protocell interactivity could provide more complex and synergistic functions,s uch as resilience to environmental stress,c hemical signalling for artificial quorum sensing,a nd multiplex tasking via collaboration and specialization. Chemical communication and signalling have been demonstrated between populations of vesicles and bacteria, [12,13] lipid vesicles containing gene circuitry, [14] vesicles and proteinosomes, [15] colloidosomes, [16] modified [17] or immobilized [18] coacervate droplets,a nd in water-in-oil emulsion droplets. [19][20][21] Hierarchically structured compartments involving different types of protocells,such as liposome-encapsulated coacervate droplets, [22] multi-compartmentalized polymersomes, [23] nes...