ND-TPE-COOH: Protein-activated fluorescent diagnostic probes for rapid identification and resection of liver tumors

Accurate diagnosis and effective treatment of primary liver tumors are crucial, and optical imaging is widely used in clinical image-guided surgery. The poor stability of traditional dyes and the non-specific binding of proteins can easily lead to misdiagnosis in qualitative assays. We have developed a protein-actived nano-fluorescent probe, ND-TPE-COOH, to label normal liver cells/tissues safely for contrast enhancement, highlighting liver tumor tissue via negative staining. ND-TPE-COOH shows weak emission when well dispersed but strong fluorescence upon aggregation due to restricted intramolecular motion. The probe exhibited exceptional labeling efficiency in liver tissues, as demonstrated by co-culturing normal human liver and human hepatocellular carcinoma cells, as well as through paraffin-embedded section analysis. Further validation was achieved via in vivo self-contrast fluorescence labeling imaging in subcutaneous xenograft and orthotopic liver tumor mouse models, confirming the utility of ND-TPE-COOH for rapid liver tumor identification through negative staining. Additionally, electrophoresis was utilized to separate membrane and cytoplasmic proteins from the two cell lines, providing insights into the specific labeling mechanisms of ND-TPE-COOH. Moreover, ND-TPE-COOH also shows stronger fluorescence in a frozen state. This probe is vital for accurate in vivo disease diagnosis through negative staining. We aspire for our current research to provide further physical insights that can contribute to cancer therapeutics.