Adaptation of nappa for surface plasmon resonance imaging analyses

A nucleic acid programmable protein array for surface plasmon resonance imaging (NAPPA-SPRi) comprising:

• a borosilicate slide;
• a gold layer disposed on the borosilicate slide;
• an amine-terminated polyethylene glycol monolayer disposed on the gold layer;
• and
• a plurality of discrete array spots disposed on the monolayer, each array spot comprising:
• plasmid DNA encoding a respective protein of interest, the respective protein of interest being fusion tagged with a targeting moiety;
• a poly(L-lysine) polymer that captures the plasmid DNA;
• and
• a capture moiety that specifically binds the targeting moiety, wherein the amine-terminated polyethylene glycol monolayer covalently links the poly(L-lysine) polymer and capture moiety to the surface of the borosilicate slide, and wherein, upon cell-free expression from the plasmid DNA, the respective protein of interest is capturable at the array spot by the capture moiety.

A method of detecting interactions between a targeting agent and one or more proteins of interest, comprising:

• providing a nucleic acid programmable protein array comprising plasmid DNA encoding a plurality of proteins of interest, a poly(L-lysine) polymer, and a capture moiety that specifically binds a targeting moiety of the proteins of interest;
• expressing the plurality of proteins of interest on the array using a cell-free protein expression system;
• contacting the array with a targeting agent that binds to one or more of the proteins of interest;
• and
• detecting binding of the targeting agent to the one or more proteins of interest using surface plasmon resonance imaging (SPRi).