Biopolymer-mediated assembly of nanoparticles using genetically encoded proteins

A method of conjugating a polypeptide to a semiconductor nanoparticle, the method comprising:

• synthesizing a nanoparticle core;
• optionally solubilizing the nanoparticle core, thereby producing a solubilized nanoparticle core;
• combining the solubilized nanoparticle core with semiconductor precursors and a polypeptide comprising a peptide linker, thereby forming a reaction mixture;
• and
• incubating the reaction mixture under conditions that permit formation of a semiconductor shell around the solubilized nanoparticle core and conjugation of the polypeptide to a surface of the semiconductor shell through a peptide linker, thereby producing a nanoparticle-polypeptide conjugate.

A method of producing a biopolymer scaffold, the method comprising:

• expressing in a first recombinant bacterial cell a first polynucleotide encoding a protein linked to a peptide linker;
• isolating the protein linked to a peptide linker;
• conjugating the protein to nanoparticles through the peptide linker, thereby forming nanoparticle-protein conjugates;
• expressing in a second recombinant bacterial cell a second polynucleotide encoding a subunit of a biopolymer linked to a peptide tag that forms a covalent isopeptide bond with the protein, thereby forming tag-displaying biopolymers;
• combining the nanoparticle-protein conjugates with the tag-displaying biopolymers to form a reaction mixture;
• and
• incubating the reaction mixture under conditions that permit isopeptide bond formation between the proteins of the nanoparticle-protein conjugates and the peptide tags of the tag-displaying biopolymers, thereby producing a biopolymer scaffold.

A method of producing an optoelectronic device, comprising:

• (a) culturing on a dielectric layer of a substrate recombinant bacterial cells that express (i) a first polynucleotide encoding a subunit of a biopolymer linked to a first peptide tag and (ii) a second polynucleotide encoding a subunit of a biopolymer linked to a second peptide tag, wherein the substrate contains a gate electrode on a surface of the substrate;
• (b) contacting the recombinant bacterial cells with (iii) a carbon nanotube linked to a first protein that forms a covalent isopeptide bond with the first peptide tag and (iv) a nanoparticle linked to a second protein that forms a covalent isopeptide bond with the second tag;
• and
• (c) depositing onto recombinant bacterial cells of (b) a source electrode and a draw electrode, thereby producing an optoelectronic device.

An optoelectronic device comprising:

• (a) a substrate containing a dielectric layer and a gate electrode on respective surfaces of the substrate;
• (b) a plurality of first biopolymers linked to first peptide tags and a plurality of second biopolymers linked to second peptide tags;
• (c) a plurality of carbon nanotubes linked to first proteins that form covalent isopeptide bonds with the first peptide tags and a plurality of nanoparticles linked to second proteins that form covalent isopeptide bonds with the second peptide tags;
• and
• (d) source and draw electrodes, wherein the plurality of (a), the plurality of (b), and the source and draw electrodes are located on the dielectric layer of the substrate.