Enzyme-mediated nitric oxide production in vasoactive erythrocyte membrane-enclosed coacervate protocells


The design and construction of synthetic therapeutic protocells capable of establishing cognate chemical communication channels with living cells is an important challenge for synthetic biology and bio-engineering. Here we develop a step towards protocell-mediated nitric-oxide-induced vasodilation by constructing a new synthetic cell model based on bio-derived coacervate vesicles with high haemocompatibility and increased blood circulation times. The hybrid protocells are prepared by the spontaneous self-assembly of haemoglobin-containing erythrocyte membrane fragments on the surface of preformed polysaccharide–polynucleotide coacervate micro-droplets containing glucose oxidase. We use the sequestered enzymes to program a spatially coupled glucose oxidase/haemoglobin reaction cascade, which in the presence of glucose and hydroxyurea generates a protocell-mediated flux of nitric oxide that we exploit for in vitro and in vivo blood vessel vasodilation. Taken together, our results provide new opportunities for the development of endogenously organized cell-like entities (biocompatible micro-bots) geared specifically towards active interfacing with individual living cells and cell communities.

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Fig. 1: Structure and function of bio-derived hybrid protocells.
Fig. 2: Construction and characterization of erythrocyte membrane-encapsulated coacervate protocells.
Fig. 3: Haemocompatibility of coacervate-based protocells.
Fig. 4: Blood circulation and in vivo biodistribution.
Fig. 5: Protocell-mediated generation of NO.
Fig. 6: Protocell-induced NO-mediated blood vessel vasodilation.

Data availability

The data analysed and used to support this study can be found within the main text and Supplementary Information.


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We thank the National Natural Science Foundation of China (21735002, 21778016, 21675047, 21874035) for financial support. The work was partly supported by the BBSRC (BB/P017320/1), the ERC Advanced Grant Scheme (EC-2016-ADG 740235) and BrisSynBio, a BBSRC/EPSRC Synthetic Biology Research Centre (BB/L01386X/1). We thank C. Xu for fruitful discussions, and Rencai Animal Hospital in Changsha for rabbit experiments.

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S.L., K.W., J.L. and S.M. conceived the experiments. S.L., Y.Z., Z.Z. and L.X. performed the experiments. All the authors undertook the data analysis, and S.L., J.L. and S.M. wrote the manuscript.

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Correspondence to Jianbo Liu or Stephen Mann.

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Liu, S., Zhang, Y., Li, M. et al. Enzyme-mediated nitric oxide production in vasoactive erythrocyte membrane-enclosed coacervate protocells. Nat. Chem. 12, 1165–1173 (2020). https://doi.org/10.1038/s41557-020-00585-y

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