a dipeptidyl peptidase 4 probe; BCD defines the backbone of the probe comprising an aniline derivative as on/off switch, a 7-amino-4-methyl-2(1H)-quinolinone (cs-124) as antenna moiety, and a diethylenetriamine-N,N,N',N'',N'''-pentaacetic acid (DTPA) as chelator moiety, Tb=terbium; structure in first source
