A tissue-selective, biocompatible contrast agent enables the visual identification of tumors and tumor margins during procedures

Dye-based chromoendoscopy (DBC) helps endoscopists visualize colorectal mucosa and identify inflammatory polyps that could progress toward colorectal cancer in patients with inflammatory bowel disease (IBD). However, current dyes often present similar uptake in tumors as normal tissue and do not improve recognition of tumor margins.

Biocompatible and biodegradable micelles loaded with the visually detectable Zinc Phthalocyanine (ZnPC) dye are generated to enable selective delivery into tumors with minimal uptake in normal tissue. Upon injection, the ZnPC-loaded micelles clearly demarcate tumor margins in the colon and small intestine tissues.

The inventors use micelles composed of diblock copolymer poly(ethylene glycol)-co-poly(caprolactone) (PEG-PCL) to effectively encapsulate various hydrophobic derivatives of the blue dye, ZnPC. The formed nanoparticles selectively deliver ZnPC into tumors either via the enhanced permeability and retention (EPR) effect or through modulation of the micelle surface with tissues targeting ligands. Both methods enhance contrast by limiting dye uptake by normal tissues. Upon accumulation in polyps, the blue color coming from ZnPC can be directly observed by the naked eye.

• Biodegradable and biocompatible copolymer
• Direct visualization of tumors and tumor margins
• Selective uptake by tumor tissue
• A fast and high-contrast method
• Alternative imaging methods such as photoacoustic imaging, fluorescence, and absorbance can also be applied