NIR Imaging of the Integrin-Rich Head and Neck Squamous Cell Carcinoma Using Ternary Copper Indium Selenide/Zinc Sulfide-Based Quantum Dots

SIMPLE SUMMARY: Despite improved patient outcomes in a range of cancers, the prognostic of head and neck cancers remain poor, with more than 507,000 deaths annually. The management of these cancers requires multidisciplinary treatments, including radiotherapy, chemotherapy, or targeted molecular therapy; however, surgical resection is one of the first-line treatments for patients with head and neck cancers. In order to increase the positive surgical margin rate, we proposed a tumor-specific near-infrared nanoprobe for fluorescence-guided surgery. We confirmed the high specificity of the proposed nanoprobe towards head and neck cancer cells using advanced 3D stroma-rich spheroids. ABSTRACT: The efficient intraoperative identification of cancers requires the development of the bright, minimally-toxic, tumor-specific near-infrared (NIR) probes as contrast agents. Luminescent semiconductor quantum dots (QDs) offer several unique advantages for in vivo cellular imaging by providing bright and photostable fluorescent probes. Here, we present the synthesis of ZnCuInSe/ZnS core/shell QDs emitting in NIR (~750 nm) conjugated to NAVPNLRGDLQVLAQKVART (A20FMDV2) peptide for targeting α(v)β(6) integrin-rich head and neck squamous cell carcinoma (HNSCC). Integrin α(v)β(6) is usually not detectable in nonpathological tissues, but is highly upregulated in HNSCC. QD-A20 showed α(v)β(6) integrin-specific binding in two-dimension (2D) monolayer and three-dimension (3D) spheroid in vitro HNSCC models. QD-A20 exhibit limited penetration (ca. 50 µm) in stroma-rich 3D spheroids. Finally, we demonstrated the potential of these QDs by time-gated fluorescence imaging of stroma-rich 3D spheroids placed onto mm-thick tissue slices to mimic imaging conditions in tissues. Overall, QD-A20 could be considered as highly promising nanoprobes for NIR bioimaging and imaging-guided surgery.