Fig. 5: Writing persistent scaffolds and internal layouts inside coacervate droplets.

a Photopolymerization-based scaffold writing. In HA/PDDA/BSA coacervates preloaded with DMAEMA and photoinitiator, local irradiation (405 nm) triggers BSA-mediated polymerization to PDMAEMA. The reaction proceeds preferentially near the interface, producing an elastic rim and ultimately a multicompartment coacervate with a persistent cross-linked shell. Reproduced with permission⁶⁸. Copyright 2025, Springer Nature. b Enzyme-catalyzed crosslinking as a chemical lock. HRP and H₂O₂ couple phenolic/tyrosyl residues on polypeptides within the dense phase, converting the coacervate from a flowing liquid to a gel-like solid. Reproduced with permission⁷⁰. Copyright 2025, Elsevier Inc. c Peripheral layout writing in membrane-wrapped protocells. BSA-loaded polysaccharide vesicles (P-somes) admit DEAE-dextran through the semipermeable shell. Coacervation occurs inside the lumen, nucleating multiple sub-droplets that coalesce along the inner envelope to form a persistent cortical pool. After washing away free material, the droplet-in-vesicle system retains a distinct peripheral coacervate domain whose position and morphology remain stable, illustrating boundary-directed writing. Reproduced with permission⁷². Copyright 2025, National Academy of Sciences. d Chemical writing of vacuolated layouts by amino acids. (I) Exogenous charged amino acids are selectively taken up; ion/acid–base pairing with protein side chains elevates local osmolyte levels and drives water influx, writing static, non-membranous vacuoles tunable by amino-acid identity and concentration. (II) In-droplet enzymatic conversion of L-asparagine to L-aspartic acid (asparaginase) produces transient vacuoles that appear and vanish with substrate, enabling erasable or cyclic layout writing. Reproduced with permission⁷⁴. Copyright 2025, Springer Nature. e Ligation-written nucleus-like subdomain. (I) Schematic: in-droplet non-enzymatic ligation elongates DNA and condenses a liquid-crystalline subdomain (LC-in-ISO) as a persistent layout. (II) Confocal evidence: SYBR Gold images at t = 0 and 24 h show a brighter internal subdomain (ISO → LC-in-ISO) (scale bar: 10 μm). Reproduced with permission⁷⁵. Copyright 2023, Springer Nature.