Hydrogel nanoparticles with covalently linked coomassie blue for brain tumor delineation visible to the surgeon.

Delineation of tumor margins is a critical and challenging objective during brain cancer surgery. A tumor-targeting deep-blue nanoparticle-based visible contrast agent is described, which, for the first time, offers in vivo tumor-specific visible color staining. This technology thus enables color-guided tumor resection in real time, with no need for extra equipment or special lighting conditions. The visual contrast agent consists of polyacrylamide nanoparticles covalently linked to Coomassie Blue molecules (for nonleachable blue color contrast), which are surface-conjugated with polyethylene glycol and F3 peptides for efficient in vivo circulation and tumor targeting, respectively.