In biology, stimuli-responsive multisubunit assemblies are ubiquitous, and mimicking these systems via synthetic approaches is of increasing interest. Interfacing such synthetic materials with biological systems is particularly promising for a range of biomedical applications including targeted drug delivery and molecular diagnostics. Within this class of materials are particles capable of changing morphology in response to stimuli. Enzymes are attractive and unique stimuli with great potential in this regard, as they propagate an amplified response via catalytic reactions, can be highly substrate specific, and have expression patterns sometimes associated with disease states. Nanoscale assemblies of amphiphiles are well-suited for the development of functional, stimuli-responsive systems because changes in the chemical or physical nature of the amphiphile can lead to formation, destruction, or morphological transformations. We have developed two systems that incorporate these types of properties. With the first system we demonstrate the assembly process of a peptide-alkyl amphiphile (PAA) from a ybbR peptide and an alkyl chain modified Coenzyme A (mCoA) in the presence of the enzyme PPTase. The alkyl chain is transferred onto the ybbR peptide resulting in the generation of a PAA which assembles to form well-defined fibrous structures. The second system uses the enzyme Sortase A (SrtA) to program the morphology of PAA's. The peptide shell of nanoparticles can be modified in the presence of SrtA and a second peptide fragment resulting in a change in amphiphilicity and hence a change in particle morphology. These approaches highlight the power of using enzymes to modulate the properties of nanomaterials.

Switching the morphology of nanomaterials with enzymes

245th National Meeting (2013)

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