title: [Gd(Try-TTDA)(H2O)]2-: a new MRI contrast agent for copper ion sensing.
abstract: In this study, we have developed two new L-tryptophan based contrast agents [Gd(Try-TTDA)(H(2)O)](2-) and [Gd(Try-ac-DOTA)(H(2)O)](-). Upon addition of Cu(II) to [Gd(Try-TTDA)(H(2)O)](2-), significant increases in the relaxivity (r(1)) and hydration number of [Gd(Try-TTDA)(H(2)O)](2-) were observed. However, it only induced a minute increase in the relaxivity (r(1)) in the case of [Gd(Try-ac-DOTA)(H(2)O)](-). Furthermore, the interaction of Cu(II) with the indole ring of Gd(III) complexes was explored by measuring the intrinsic fluorescence of the tryptophan of the Gd(III) complex. With the addition of one equivalent of Cu(II) to [Gd(Try-TTDA)(H(2)O)](2-) the indole fluorescence was completely quenched. Moreover, the [Gd(Try-TTDA)(H(2)O)](2-) complex shows excellent selectivity towards Cu(II) over other metal ions (Cu(II) > La(III) > Mg(II)). Importantly, the significant signal intensity (2073 ± 67) for in vitro MR imaging using [Gd(Try-TTDA)(H(2)O)](2-) in the presence of Cu(II) implicates that this new smart contrast agent ([Gd(Try-TTDA)(H(2)O)](2-)) can serve as a Cu(II) sensor for MR imaging.
authors: Department of Biological Science and Technology, National Chiao Tung University, 75 Bo-Ai Street, Hsinchu 300, Taiwan.
authors: Dayananda
authors: D
authors: Kasala
authors: Tsung-Sheng
authors: TS
authors: Lin
authors: Chiao-Yun
authors: CY
authors: Chen
authors: Gin-Chung
authors: GC
authors: Liu
authors: Chai-Lin
authors: CL
authors: Kao
authors: Tian-Lu
authors: TL
authors: Cheng
authors: Yun-Ming
authors: YM
authors: Wang
mesh_terms: D002104:Cadmium / Q000737:chemistry*; D003287:Contrast Media / Q000737:chemistry*; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D005682:Gadolinium / Q000737:chemistry*; D007700:Kinetics; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D009942:Organometallic Compounds / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000737:chemistry
chemical_list: D003287:Contrast Media; D056831:Coordination Complexes; D009942:Organometallic Compounds; D002104:Cadmium; D003300:Copper; D014364:Tryptophan; D005682:Gadolinium