Zn2+‐Responsive Bimodal Magnetic Resonance Imaging and Fluorescence Imaging Agents and Their Interaction with Human Serum Albumin. Issue 20 (5th June 2014)

• Record Type: Journal Article
• Authors: Xu, Ying‐Qi; Luo, Jian; Chen, Zhong‐Ning
• Is Part Of: European journal of inorganic chemistry. Issue 20(2014)
• Page Start: 3208
• Page End: 3215
• Publication Date: 2014-06-05
• Subjects: Fluorescent probes -- Imaging ­agents -- Gadolinium -- Human serum ­albumin -- Magnetic resonance imaging -- Zinc; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201402197
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract: The gadolinium(III) complexes GdL1 and GdL2 were designed as Zn 2+ ‐responsive bimodal magnetic resonance imaging (MRI) and fluorescence imaging probes. Upon binding to Zn 2+ ions, GdL1 exhibits a bidentate or tridentate mode to form heterodinuclear GdL1 Zn or heterotrinuclear (GdL1 )2 Zn, whereas GdL2 binds to the Zn 2+ ion only in a bidentate mode to form (GdL2 )2 Zn. The gadolinium(III) complexes derived from both H3 L1 and H3 L2 exhibit remarkable interactions with human serum albumin (HSA) at both site I and site II, which result in significant enhancements of the relaxivity and remarkable improvements of T 1 ‐weighted imaging contrast. In the presence of HSA, both the relaxivity ( r 1 ) and fluorescence exhibit 300 % enhancement with a clear blueshift of the fluorescence for GdL1 Zn, which is ascribed to direct binding to HSA through the formation of a Zn–HSA coordination bond. In contrast, the presence of HSA induces smaller relaxivity increases for GdL1 (155 %), (GdL1 )2 Zn (183 %), GdL2 (192 %), and (GdL2 )2 Zn (181 %); these increases are ascribed to weaker hydrophobic interactions or stereospecificity with HSA. The contrast of T 1 ‐weighted phantom MR images of these gadolinium(III) complexes in human serum (HS) is much improved relative to that in 4‐(2‐hydroxyethyl)‐1‐piperazineethanesulfonic acid (HEPES) buffer solutions. Abstract : Gadolinium(III)‐based bimodal magnetic resonance imaging (MRI) and fluorescence imaging agents exhibit strong coordination or noncovalent interactions with human serum albumin (HSA) and, thus, induce remarkable relaxivity enhancement and significant turn‐on luminescence.