Fig. 3.
Self-assembly of patchy droplets. (A) A representative confocal image of assembled alternating copolymers after a 192-h incubation. Alternating copolymer: two types of divalent droplets (P1 and P2) with complementary patches (α on P1, α′ on P2) self-assemble into a linear chain. (B) High-magnification images of two chains with fluorescent patches (red, labeled with SA-AF 647) at each joint, confirming that the assembly is through interpatch binding. (C) A gallery of several long chains. (D) The chain length distributions at various time points (only unbranched oligomers are counted in the main panel). Each data point represents the frequency of the linear oligomer of a certain length in the sample. (Inset) Number fractions of droplets in linear alternating chains, branched structures (e.g., a structure containing one P1 binds to more than two P2), and structures containing nonspecific bindings (e.g., P1 binds to P1) versus time. (E) A representative confocal image of self-assembled hetero tetramers. “Hetero tetramer”: Two monovalent droplets (O1 and O4) and two divalent droplets (O2 and O3) with patches bearing preprogrammed binding specificity (α on O1, α′ and β on O2, β′ and γ on O3, γ′ on O4) self-assemble into a tetramer. (F) A representative confocal image of trivalent clusters. “Trivalent cluster”: One trivalent droplet (C1) and three monovalent droplets (C2) with patches bearing preprogrammed binding specificity (three α on C1 and one α′ on C2) self assemble into a trivalent cluster. (Scale bars, 5 μm.)