Targeting of Mannose Receptor with Fluorescent Nanodiamonds—Implications for Locoregional Cancer Diagnostics

A sensitive and specific approach for visualization of lymph nodes with or without tumor cell metastasis using ultrabright 200-nm fluorescent nanodiamonds (FNDs) equipped with a designed targeting surface architecture will be presented. The FNDs with a narrow size distribution were isolated by differential centrifugation, colloidally stabilized with alkyne-functionalized poly(glycerol) and modified with a polyvalent array of mannose. <i>In vitro</i> experiments demonstrated an outstanding increase of the particle internalization by the mannose receptor CD206 (MR) and no significant <i>in vitro</i> toxicity. MR involvement was confirmed by blocking ligand binding with mannan and a 15.2 mAb (anti-MR) in J774A.1 mouse macrophage tumor cells. <i>In vivo</i> mouse experiments confirmed increased retention of FND-p-Man in sentinel lymph nodes of both healthy and tumor-bearing animals. These results suggest that FND-p-Man has a potential as a tracer for lymph node visualization in locoregional cancer diagnostics and as a tool for endoscopic/robot-guided surgery.