Recoveries from screening phage displayed libraries against the soluble ectodomain of PSMA.

<p>Recoveries from screening phage displayed libraries against the soluble ectodomain of PSMA.</p

Structure of the Peptide 562 tetramer.

<p>Structure of the Peptide 562 tetramer.</p

Binding and internalization of 5FAM-562 and 5FAM-563 in LNCaP cells.

<p>5FAM-562 (1 µM, <i>A–C</i>, green) and 5FAM-563 (1 µM , <i>D–F</i>, green) bound and internalized in LNCaP cells and co-localized with PSMA in intracellular vesicles visualized with anti-PSMA-Mab (red, scale is 20 µm).</p

Sequences of phage clones isolated after 3-round of panning and IC₅₀ values of the peptides analyzed.

*<p>Cys(Acm) in peptides 564 and 565.</p>†<p>Ki value from the Cheng-Prussof equation.</p>a<p>, no inhibition observed at 14.5 µM.</p>b<p>, no inhibition observed at 55.5 µM.</p>c<p>, no inhibition observed at 1 mM.</p><p>nd, not determined.</p

Immunofluorescence microscopy of phage clones from round 2 of panning.

<p><i>(A)</i> PSMA (100 nM) inhibited the binding of Clone 1 (ARLSHRPSYLLVCA) and Clone 2 (GTAVASRVYSLHSLM) to PSMA-postive LNCaP cells, indicating that the uptake was receptor specific (scale is 30 µm). <i>(B)</i> Immunofluorescence microscopy of phage clones from round 2 of panning indicate that the panning process is biased toward PSMA binding (“*” denotes <i>P<0.05</i>).</p

Immunofluorescence microscopy of phage clones from round 3 of panning.

<p>Randomly selected PSMA-targeted phage clones (C, E, G, H, J, L) from the third round of screening bound specifically to LNCaP cells (“L”), but not PC3 cells (“P”). While staining was preferentially bound at cell surface, there was evidence of internalization (scale 20 µm).</p

Tunable Ultrasmall Visible-to-Extended Near-Infrared Emitting Silver Sulfide Quantum Dots for Integrin-Targeted Cancer Imaging

The large size of many near-infrared (NIR) fluorescent nanoparticles prevents rapid extravasation from blood vessels and subsequent diffusion to tumors. This confines <i>in vivo</i> uptake to the peritumoral space and results in high liver retention. In this study, we developed a viscosity modulated approach to synthesize ultrasmall silver sulfide quantum dots (QDs) with distinct tunable light emission from 500 to 1200 nm and a QD core diameter between 1.5 and 9 nm. Conjugation of a tumor-avid cyclic pentapeptide (Arg-Gly-Asp-DPhe-Lys) resulted in monodisperse, water-soluble QDs (hydrodynamic diameter < 10 nm) without loss of the peptide’s high binding affinity to tumor-associated integrins (<i>K</i>_I = 1.8 nM/peptide). Fluorescence and electron microscopy showed that selective integrin-mediated internalization was observed only in cancer cells treated with the peptide-labeled QDs, demonstrating that the unlabeled hydrophilic nanoparticles exhibit characteristics of negatively charged fluorescent dye molecules, which typically do not internalize in cells. The biodistribution profiles of intravenously administered QDs in different mouse models of cancer reveal an exceptionally high tumor-to-liver uptake ratio, suggesting that the small sized QDs evaded conventional opsonization and subsequent high uptake in the liver and spleen. The seamless tunability of the QDs over a wide spectral range with only a small increase in size, as well as the ease of labeling the bright and noncytotoxic QDs with biomolecules, provides a platform for multiplexing information, tracking the trafficking of single molecules in cells, and selectively targeting disease biomarkers in living organisms without premature QD opsonization in circulating blood