Construction and validation of nano gold tripods for molecular imaging of living subjects.

Anisotropic colloidal hybrid nanoparticles exhibit superior optical and physical properties compared to their counterparts with regular architectures. We herein developed a controlled, stepwise strategy to build novel, anisotropic, branched, gold nanoarchitectures (Au-tripods) with predetermined composition and morphology for bioimaging. The resultant Au-tripods with size less than 20 nm showed great promise as contrast agents for in vivo photoacoustic imaging (PAI). We further identified Au-tripods with two possible configurations as high-absorbance nanomaterials from various gold multipods using a numerical simulation analysis. The PAI signals were linearly correlated with their concentrations after subcutaneous injection. The in vivo biodistribution of Au-tripods favorable for molecular imaging was confirmed using small animal positron emission tomography (PET). Intravenous administration of cyclic Arg-Gly-Asp-d-Phe-Cys (RGDfC) peptide conjugated Au-tripods (RGD-Au-tripods) to U87MG tumor-bearing mice showed PAI contrasts in tumors almost 3-fold higher than for the blocking group. PAI results correlated well with the corresponding PET images. Quantitative biodistribution data revealed that 7.9% ID/g of RGD-Au-tripods had accumulated in the U87MG tumor after 24 h post-injection. A pilot mouse toxicology study confirmed that no evidence of significant acute or systemic toxicity was observed in histopathological examination. Our study suggests that Au-tripods can be reliably synthesized through stringently controlled chemical synthesis and could serve as a new generation of platform with high selectivity and sensitivity for multimodality molecular imaging.

Floresorchestia xueli, a new terrestrial crustacean (Amphipoda, Talitridae) from Yunnan, China.

A new species, Floresorchestia xueli Tong Hou, sp. nov. is described from high altitude habitats of Yunnan, China. The species differs morphologically from its congeners by left mandible lacinia mobilis having four teeth; coxal gills complexly lobed and convoluted; epimeral plates IIIII without slits; telson with one slender facial spine and two terminal spines on each lobe. Analysis of DNA barcode sequences and niche distinctiveness support recognition of the new species.

Two species of Talitridae (Crustacea, Amphipoda) from Kenya.

Two species of the family Talitridae Rafinesque, 1815 are described from English Point Beach, Mkomani, Mombasa, Kenya. One new species Floresorchestia mkomani Bichang'a Hou, sp. nov. is reported and Gazia gazi Lowry Springthorpe, 2019 is redescribed. The new species is characterized by the five dentate lacinia mobilis on the left mandible in male and only four in female, pereopod IV dactylus thickened proximally and having a small protrusion towards the mid of its posterior margin, a sexually dimorphic pereopod VII, and the presence of vertical slits just above the ventral margin of epimera II and III. Detailed morphological characteristics, as well as comparisons with closely related species are provided. To ascertain the species delimitation, molecular evidence is availed in this paper. Type material is deposited in National Museums of Kenya (NMK).

Affibody modified and radiolabeled gold-iron oxide hetero-nanostructures for tumor PET, optical and MR imaging.

A highly monodispersed hetero-nanostructure with two different functional nanomaterials (gold (Au) and iron oxide (Fe(3)O(4,) IO)) within one structure was successfully developed as Affibody based trimodality nanoprobe (positron emission tomography, PET; optical imaging; and magnetic resonance imaging, MRI) for imaging of epidermal growth factor receptor (EGFR) positive tumors. Unlike other regular nanostructures with a single component, the Au-IO hetero-nanostructures (Au-IONPs) with unique chemical and physical properties have capability to combine several imaging modalities together to provide complementary information. The IO component within hetero-nanostructures serve as a T(2) reporter for MRI; and gold component serve as both optical and PET reporters. Moreover, such hetero-nanoprobes could provide a robust nano-platform for surface-specific modification with both targeting molecules (anti-EGFR Affibody protein) and PET imaging reporters (radiometal (64)Cu chelators) in highly efficient and reliable manner. In vitro and in vivo study showed that the resultant nanoprobe provided high specificity, sensitivity, and excellent tumor contrast for both PET and MRI imaging in the human EGFR-expressing cells and tumors. Our study data also highlighted the EGFR targeting efficiency of hetero-nanoparticles and the feasibility for their further theranostic applications.

Molecular optical imaging with radioactive probes.

BACKGROUND: Optical imaging (OI) techniques such as bioluminescence and fluorescence imaging have been widely used to track diseases in a non-invasive manner within living subjects. These techniques generally require bioluminescent and fluorescent probes. Here we demonstrate the feasibility of using radioactive probes for in vivo molecular OI. METHODOLOGY/PRINCIPAL FINDINGS: By taking the advantages of low energy window of light (1.2-3.1 eV, 400-1000 nm) resulting from radiation, radionuclides that emit charged particles such as beta(+) and beta(-) can be successfully imaged with an OI instrument. In vivo optical images can be obtained for several radioactive probes including 2-deoxy-2-[(18)F]fluoro-D-glucose ([(18)F]FDG), Na(18)F, Na(131)I, (90)YCl(3) and a (90)Y labeled peptide that specifically target tumors. CONCLUSIONS/SIGNIFICANCE: These studies demonstrate generalizability of radioactive OI technique. It provides a new molecular imaging strategy and will likely have significant impact on both small animal and clinical imaging.