Monomolecular Multimodal Fluorescence-Radioisotope Imaging Agents

Abstract

Diagnosis of diseases by different imaging methods can provide complementary information about the functional status of diseased tissues or organs. To overcome the current difficulties in coregistering images from different imaging modalities with a high degree of accuracy, we prepared near-infrared (NIR) monomolecular multimodal imaging agents (MOMIAs) consisting of a heptamethine carbocyanine and 111In-DOTA chelate that served as antennae for optical and scintigraphic imaging, respectively. Their spectral properties clearly show that coordination of indium to MOMIA increased the fluorescence intensity of the compounds. The MOMIAs are exceptionally stable in biological media and serum up to 24 h at 37 degrees C. Biodistribution of the compounds in mice obtained by fluorescence photon and gamma-counts demonstrated a similar distribution trend of the molecular probe in different tissues, suggesting that the detected fluorescence and gamma-emissions emanated from the same source (MOMIA). At 24 h postinjection, the MOMIAs were excreted by the renal and hepatobiliary systems and the blood level of a representative MOMIA was very low, thereby reducing background noise caused by circulating molecular probes. These findings demonstrate the feasibility of preparing single molecules with the capacity to emit discernible and diagnostic fluorescent and gamma-radiations for optical and nuclear imaging of living organisms.

Synthesis and Characterization of Core–Shell Star Copolymers for In Vivo PET Imaging Applications

“…Fractional precipitation was carried out with an acetone/hexanes combination several times until the remaining arm copolymers were removed to yield a white powder (yield: 0.242 g, 29%, s3-e). 56,57 Compound 1 (1.00 g, 1.75 mmol) and N-hydroxysuccinimide (NHS, 0.502 g, 4.37 mmol) were dissolved in anhydrous DMF (10 mL). After the solution was cooled to 0°C, N,N,N′,N′-tetramethyl-O-(1H-benzotriazol-1-yl)uronium hexafluorophosphate (HBTU, 0.761 g, 2.01 mmol) and triethylamine (TEA, 0.265 g, 2.62 mmol) were added to the solution, and the mixture was stirred for 15 min.…”

Image-Guided Enzyme/Prodrug Cancer Therapy

“…To further validate the optimal timing of prodrug injection, the biodistribution of bCD-PLL at 2 and 24 h after administration was measured according to the optical method of Zhang et al (24). At 2 h, most of the enzyme was detected in the kidney and liver (Fig.…”

“…Characterization of the bCD-PLL biodistribution was done according to a previously reported protocol (24). Briefly, mice (n = 3, wt) were sacrificed at 2 or 24 h after i.v.…”

Dual-tracer background subtraction approach for fluorescent molecular tomography

“…4 Furthermore, at these extended time points there may still be considerable nonspecific tracer concentrations in organs of filtration like the liver, kidneys, spleen, and bladder, confounding the ability to localize bound fractions of the tracer, at least in the abdomen. 5 This study develops one new approach toward advancing this area.…”