Patent ID: 6921496

Claim:
A composition comprising: a semiconductor nanocrystal, a linking group which has a distal end and a proximal end, the distal end being bound to an outer surface of the semiconductor nanocrystal and the proximal end comprising a first charged or ionizable moiety, wherein the distal end comprises S, N, P, O, or O═P; the first charged or ionizable moiety is selected from the group consisting of a hydroxide, an alkoxide, a carboxylate, a sulfonate, a phosphate, a phosphonate and a quaternary ammonium; and the distal and proximal ends are connected by a spacer or a bond, and a fusion protein comprising a second charged or ionizable moiety, wherein the first and second charged or ionizable moieties electrostatically associate the semiconductor nanocrystal with the fusion protein to form an ionic conjugate.