Three Compartment Liposome Fusion: Functional Protocells for Biocatalytic Cascades and Operation of Dynamic DNA Machineries

Nucleic acid-functionalized liposomes modified at their boundaries with o-nitrobenzyl phosphate-caged hairpin units and pH-responsive C-G center dot C+ triplex forming strands are used for the concomitant light and pH-triggered fusion of three types of loaded liposomes. The fusion processes are followed by light-scattering size enlargement measurements, optical methods, and biocatalytic cascades activated upon the mixing of the liposomes loaded with enzymes and their substrates and their fusion into the cell-like containments. The fused liposomes act as functional protocells for the integration of biocatalytic machineries. This is exemplified by the operation of an autonomous polymerization/nickase machinery synthesizing a Mg2+-ion-dependent DNAzyme and of a transcription machinery yielding the Malachite Green-RNA aptamer product.