Self-adaptive non-covalent albumin-binding near-infrared probe conjugates enabling precise sentinel lymph node metastasis illumination and primary tumor imaging

Tumor sentinel lymph node (SLN) metastasis plays a vital role in tumor staging and therapeutic decision-making process. However, precise diagnosis of primary tumors and lymphatic metastases is still hindered by low imaging resolution and poor photostability of fluorescent probes. Herein, we report three novel IR820-fatty acid (FA) conjugates (IR-OA, IR-LA, and IR-PA) for precise lymphatic metastasis illumination and primary tumor diagnosis. The IR-FA conjugates are able to non-covalently bound to albumin in vivo, and the fluorescence quantum yield is significantly enhanced after incubation with bovine serum albumin (BSA) in vitro. Moreover, the BSA-IR-FA conjugates display large Stokes shift (> 120 nm), dramatically improving in vivo imaging resolution. Among them, IR-PA demonstrates distinct advantage over IR-OA, IR-LA, and IR-maleimide (MAL) (fluorescent probe previously reported by our group) in terms of fluorescence quantum yield, photostability, and imaging resolution. As a result, IR-PA exhibits satisfactory imaging results with high fluorescence intensity and imaging resolution in sentinel lymph node metastasis illumination and primary tumor location. Our findings provide a self-adaptive albumin-binding near-infrared probe conjugate for accurate diagnosis of primary tumors and lymphatic metastases.

Automated summary

This study reports three novel IR820-fatty acid conjugates for precise lymphatic metastasis illumination and primary tumor diagnosis. The conjugates are able to bind to albumin in vivo and display significantly enhanced fluorescence quantum yield and imaging resolution after incubation with bovine serum albumin in vitro. Among them, IR-PA shows distinct advantage in terms of fluorescence quantum yield, photostability, and imaging resolution.