Engineering Solid Binding Proteins for the Biofabrication of Environmentally Friendly Multi-functional Quantum Dots

Methods that emulate Nature's remarkable ability to synthesize chemically and structurally intricate architectures are of considerable interest for the fabrication of industrially-relevant materials and systems. In this work, we design and engineer solid-binding proteins that drive the formation and assembly of multi-functional nanomaterials. We first describe a method to biomineralize Mn-doped ZnS immuno-quantum dots with a minimized protein and study how such protein-coated nanocrystals are taken up by, and impact the physiology of the model bacterium Escherichia coli. We next design and build ZnS-binding derivatives of Green Fluorescent Protein to mineralize nanocrystals that combine inorganic and organic fluorescence properties and combine these with DNA aptamers and silica phases to create small-molecule sensors. Finally, we demonstrate that solid-binding proteins can be used to solubilize carbon nanotubes and to selectively label their ends. Collectively, our results emphasize the power of protein engineering for the environmentally friendly synthesis of functional nanomaterials.