Patent ID: 7592188

Claim:
A biosensor comprising: (a) a binding domain with specific affinity for a target molecule; and, (b) an environmentally sensitive dye covalently linked to the binding domain; wherein the dye is a compound of one of the following formulae: wherein: R 1 is lower alkyl, —(CH 2 ) 3 —SO 3 − , —(CH 2 ) 3 —NH—CO—CH 2 —I or —(CH 2 ) 3 —N + (CH 3 ) 2 —(CH 2 ) 2 —NCS; R 2 is H, —NH 2 , —SO 3 − , CH 3 CONH—, ICH 2 CONH—, HO(CH 2 ) 2 —S—CH 2 CONH—; SuOCOCH 2 OCH 2 CON(CH 3 )— or a protecting group; and R 3 is lower alkyl or tolyl-acetonitrile.