title: Photoacoustic Probes for Ratiometric Imaging of Copper(II).
abstract: Photoacoustic tomography has emerged as a promising alternative to MRI and X-ray scans in the clinical setting due to its ability to afford high-resolution images at depths in the cm range. However, its utility has not been established in the basic research arena owing to a lack of analyte-specific photoacoustic probes. To this end, we have developed acoustogenic probes for copper(II)-1 and -2 (APC-1 and APC-2, a water-soluble congener) for the chemoselective visualization of Cu(II), a metal ion which plays a crucial role in chronic neurological disorders such as Alzheimer's disease. To detect Cu(II), we have equipped both APCs with a 2-picolinic ester sensing module that is readily hydrolyzed in the presence of Cu(II) but not by other divalent metal ions. Additionally, we designed APC-1 and APC-2 explicitly for ratiometric photoacoustic imaging by using an aza-BODIPY dye scaffold exhibiting two spectrally resolved NIR absorbance bands which correspond to the 2-picolinic ester capped and uncapped phenoxide forms. The normalized ratiometric turn-on responses for APC-1 and APC-2 were 89- and 101-fold, respectively.
authors.affiliation: Roger Adams Laboratory, Department of Chemistry, University of Illinois , 600 South Mathews Avenue, Urbana, Illinois 61801, United States.
authors.forename: Hao
authors.initials: H
authors.lastname: Li
authors.affiliation: Roger Adams Laboratory, Department of Chemistry, University of Illinois , 600 South Mathews Avenue, Urbana, Illinois 61801, United States.
authors.forename: Pamela
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Roger Adams Laboratory, Department of Chemistry, University of Illinois , 600 South Mathews Avenue, Urbana, Illinois 61801, United States.
authors.forename: Lukas P
authors.initials: LP
authors.lastname: Smaga
authors.affiliation: Roger Adams Laboratory, Department of Chemistry, University of Illinois , 600 South Mathews Avenue, Urbana, Illinois 61801, United States.
authors.forename: Ryan A
authors.initials: RA
authors.lastname: Hoffman
authors.affiliation: Roger Adams Laboratory, Department of Chemistry, University of Illinois , 600 South Mathews Avenue, Urbana, Illinois 61801, United States.
authors.forename: Jefferson
authors.initials: J
authors.lastname: Chan
mesh_terms: D000162:Acoustics; D003300:Copper / Q000737:chemistry*; D015335:Molecular Probes
chemical_list: D015335:Molecular Probes; D003300:Copper