Scientists develop phagocytic protocells capable of the targeted delivery of enzymes

Researchers at the University of Bristol have designed a community of artificial cell-like droplets that collectively displays a simple form of phagocytosis behavior. The work provides a new approach to designing complex life-like properties in non-living materials. 

The chemists have made a major advance in the construction of synthetic communities of artificial cells capable of mimicking phagocytosis-a complex biological process seen in living cells that enables the ingestion of foreign material by certain cell types.

In the new work, the researchers led by Professor Stephen Mann designed a protocell community consisting of a mixture of two different types of nanoparticle-coated aqueous micro-droplets that collectively exhibit a simple form of artificial phagocytosis. The droplets are either small and surrounded by a semi-permeable crosslinked silica membrane (colloidosomes), or large and enclosed by a porous non-crosslinked iron oxide shell (magnetic emulsion droplets).

When the two types of protocells are mixed together in oil, they undergo collisions but do not interact. However, if a fatty acid is added to the oil then the magnetic emulsion droplets develop an aperture in their iron oxide shell through which the smaller colloidosomes are ingested when the protocells come into contact. As a result, the colloidosomes are captured and remain trapped within the water-filled interior of the larger protocells.

Professor Stephen Mann said: "Our long-term aim is to build on this latest work by developing a portfolio of protocell behaviours that mimic complex life-like properties ranging from artificial phagocytosis, predation and chemical communication with applications that can be used to clean up pollutants, store and release drugs, monitor chemical reactions, and serve as models for the origin of life."