1. An assay comprising: a live cell derived from a source having a condition, wherein the live cell having a plurality of a receptor on a cell surface, the receptor capable of binding a ligand, whereupon binding of the ligand by said plurality of a receptor a detectable pattern of the plurality of receptors distributed on the surface of the cell is activated and said detectable pattern comprises a signature for the condition; and a physical context having the ligand attached thereto.