An antigen-strengthened dye-modified fully-human-nanobody-based immunoprobe for second near infrared bioimaging of metastatic tumors.

Shi, Yibing; Wu, Huifang; Hu, Weiqiang; Jin, Yujia; Kong, Mengya; Wang, Yulu; Chen, Binfan; Li, Quanxiao et al. · Biomaterials · 2022

basic_science · Level V

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Abstract

Conventional immunoprobes have absorption capabilities across the visible to near infrared (NIR-I, 650-900 nm) region. Recently, second near infrared (NIR-II, 1000-1700 nm) window have gained much attention due to their deeper penetration depth and improved visualization. Here, we describe the design and synthesis of a fully human nanobody-based fluorescent immunoprobe (ICGM-n501) for NIR-II bioimaging with strengthened fluorescent emission by antigen for the first time. By site-directed conjugation of an FDA-approved dye analogue, indocyanine green decorated with maleimide (ICGM), into a tumor-specific n501, ICGM-n501 provides real-time monitoring of abdominal transportation pathway of antibody-based bioagents with high resolution (0.21 mm), presents better accuracy and lower dosage (0.21 μmol kg<sup>-1</sup>) in bioimaging of peritoneal metastatic tumors than bioluminescence agent D-luciferin. In this work, ICGM-n501 demonstrates its potential in clinical surgery guidance, provide an expanded category of available NIR-II fluorophores and a template for next-generation immunoassay bioagents.