A Self-Reorganizing Multilayer to Release Free Proteins from Self-Assemblies

The deconstruction of self-assemblies based on proteins and polyelectrolytes (PEs) and the subsequent release of intact proteins requires either a switch from attractive to repulsive mode or particular PE properties (degradability, responsiveness, differential affinity). Here, an interfacial self-assembly made of three charged species, i.e. a strong polyacid complexed with a protein and a weak polybase, is shown to self-reorganize upon pH shift. When the pH takes a value that is one pH unit lower than the pKa of the weak polybase, the two PEs associate, thereby releasing the protein. The disassembly thus relies on associative forces rather than on the alteration of the protein-PE coupling strength. Hence, it allows the release of a protein using two simple PEs. The method is illustrated for lysozyme, which recovered up to half of its initial bioactivity after release. In contrast, a control self-assembled film that could not reorganize only maintained about 21% of the protein bioactivity after disassembly...