Self-assembly of nanomaterials into films and fibers using genetically engineered viruses
Genetically engineered M13 bacteriphage (viruses) were used to self-assemble various nanomaterials (ZnS, Au, fluorescein, and phycoerythrin) into films and fibers. The filamentous viruses, which were the basic building block of the self-ordering system, were selected through phage display for their specific recognition moieties for desired materials surfaces. The M13 viruses coupled with ZnS nanocrystals spontaneously evolved a self-supporting hybrid film material that was ordered at the nano-scale and micron-scales. Periodic domains were continuously propagated over a centimeter length scale, an observance that was verified using various optical and electron microscopy techniques. Anti-streptavidin viruses, which could specifically bind to streptavidin, were conjugated with many nanomaterials and used to modulate the nanomaterials in the self- assembled virus system. The resulting virus composite films had chiral smectic C structures due to the helical surface of the M13 virus. In addition, ~20 micrometer diameter fibers were fabricated with liquid crystalline virus suspensions using a wetspinning process that mimicked the spinning process of silk spiders. The virus was also blended with highly soluble polyvinyl pyrolidone and electrospun, resulting in nanoscale diameter fibers. This approach to aligning nanomaterials in a genetically engineered M13 virusbased liquid crystal system has several advantages. Monodisperse biopolymers (M13 viruses) of specified lengths can be easily prepared by molecular cloning techniques. By genetic selection of a peptide recognition moiety, one can easily modulate and align different types of nanomaterials into 3D ordered structures. We anticipate that our approach using recognition as well as a liquid crystalline self-assembly system of engineered viruses may provide new pathways to organizing electronic, optical, and magnetic materials.