title: Parts per billion detection of uranium with a porphyrinoid-containing nanoparticle and in vivo photoacoustic imaging.
abstract: Chemical tools that can report radioactive isotopes would be of interest to the defense community. Here we report ∼250 nm polymeric nanoparticles containing porphyrinoid macrocycles with and without pre-complexed depleted uranium and demonstrate that the latter species may be detected easily and with high sensitivity via photoacoustic imaging. The porphyrinoid macrocycles used in the present study are non-aromatic in the absence of the uranyl cation, but aromatic after cation complexation. We solubilized both the freebase and metalated forms of the macrocycles in poly(lactic-co-glycolic acid) and found a peak in the photoacoustic spectrum at 910 nm excitation in the case of the uranyl complex. The signal was stable for at least 15 minutes and allowed detection of uranium concentrations down to 6.2 ppb (5.7 nM) in vitro and 0.57 ppm (19 fCi; 0.52 μM) in vivo. To the best of our knowledge, this is the first report of a nanoparticle that detects an actinide cation via photoacoustic imaging.
authors: Department of Chemistry, The University of Texas at Austin, 105 E. 24th Street-A5300, Austin, TX 78712-1224, USA.
authors: I-Ting
authors: IT
authors: Ho
authors: Jonathan L
authors: JL
authors: Sessler
authors: Sanjiv Sam
authors: SS
authors: Gambhir
authors: Jesse V
authors: JV
authors: Jokerst
mesh_terms: D000818:Animals; D005260:Female; D019344:Lactic Acid / Q000737:chemistry; D057230:Limit of Detection; D051379:Mice; D057054:Molecular Imaging; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D061088:Photoacoustic Techniques / Q000379:methods*; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011166:Porphyrins / Q000737:chemistry*; D014501:Uranium / Q000032:analysis* / Q000737:chemistry
chemical_list: D011166:Porphyrins; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D014501:Uranium