Patent ID: 8092662

Claim:
An analyte sensor unit comprising: a housing adapted for placement on the surface of skin having a bottom surface for contacting with the skin and wherein the housing comprises: an electrochemical-based sensor having a portion within the housing and a portion exterior to the housing and having a length to permit insertion of the second portion about 2 to about 7 mm beneath the surface of the skin, wherein the electrochemical-based sensor comprises: an electrode comprising an analyte responsive enzyme and a mediator and wherein the mediator comprises: a polymeric transition metal complex comprising: a transition metal complex comprising at least one bidentate ligand; a polymer backbone; and at least one spacer attached to the polymer backbone, the at least one spacer comprising at least one non-cyclic functional group selected from the group consisting of —(CR r R s )—, —O—, —S—, —C(O)O—, —S(O) 2 NR k —, —OC(O)NR m —, —OC(S)NR n , —C(O)NR t —, —NR u —, —CR v ═N—O—, —CR w ═NNR x — and —(SiR y R z )—, and wherein R r and R s are independently hydrogen, chlorine, fluorine, or substituted or unsubstituted alkyl, alkoxy, alkenyl, or alkynyl, and R k , R m , R n , R t , R u , R v , R w , R x , R y , and R z are independently hydrogen or substituted or unsubstituted alkyl, wherein the at least one bidentate ligand of the transition metal complex is covalently coupled to the spacer.