The University of Science and Technology of China has made new progress in the study of tumor photoacoustic imaging

According to the news of the University of Science and Technology of China, the research group of Professor Liang Gaolin and the research group of Professor Yuan Yue of the School of Chemistry and Materials Science of the University of Science and Technology of China have made new progress in tumor photoacoustic imaging. The authors used tumor high-expression histoproteinase B (CTSB) to regulate small molecule photoacoustic imaging probes to self-assemble in situ into nanoprobes that are not easily pumped by cells, thereby significantly enhancing the photoacoustic imaging signal at mouse breast cancer tumors and achieving specific photoacoustic imaging of CTSB high-expression tumors. The research results were published in the internationally renowned academic journal Angewandte Chemie International Edition, DOI: 10.1002/ anie.202114766》。

For most cancers, the five-year survival rate in the early stages of the disease is much higher than in the late stages of the disease, and patients also have a relatively large number of treatment options to choose from, so early diagnosis is crucial for cancer treatment. CTSB is considered a potential marker for early cancer diagnosis due to its overexpression in a variety of cancers, and accurate and efficient assessment of CTSB activity in vivo will provide a new method for early clinical diagnosis of cancer.

Photoacoustic imaging is a new non-invasive and non-ionizing biomedical imaging method developed in recent years, which combines the high contrast, specificity and high penetration of ultrasound imaging of optical imaging, and has great application potential in biomedical research and molecular diagnosis of diseases.

Aiming at the problem of early diagnosis of cancer and the enhanced effect of the self-assembly process on the signal of the photoacoustic imaging probe, the authors designed a CTSB-specifically activated near-infrared photoacoustic imaging probe Val-Cit-Cys(SEt)-Lys(Cypate)-CBT(Cypate-CBT) based on the CBT-Cys click condensation reaction featured in this group. When Cypate-CBT enters CTSB highly expressed tumor cells, its disulfide bonds are reduced by glutathione within the cell, the specific substrate Val-Cit is recognized and sheared by CTSB, and the resulting product Cypate-CBT-Cleaved will form a circular dimer Cypate-CBT-Dimer through the cbt-Cys click reaction between molecules. The dimer is self-assembled by π-π into larger near-infrared nanoparticle cypate-CBT-NPs enriched in tumor cells, thereby enhancing photoacoustic imaging signals and prolonging photoacoustic detection time. The results of cell and animal imaging showed that the photoacoustic imaging signals in breast cancer cells and tumors in the experimental group were enhanced by 4.9 and 4.7 times, respectively, compared with the Cypate control group. By replacing the Val-Cit fragment in Cypate-CBT with another digestion sequence, more "smart" photoacoustic imaging probes can be designed to provide new ideas for the clinical diagnosis of the corresponding cancer.

The first author of the paper is Wang Chenchen, a doctoral student at the School of Chemistry and Materials Science of the University of Science and Technology of China, and Professor Gaolin Liang and Professor Yuan Yue are co-corresponding authors.

The research has been funded by the National Science Foundation for Outstanding Young Scholars, the Innovative Research Group Project of the Foundation Committee, and the Special Fund Project for basic scientific research business expenses of central universities.

Edited by Xu Dapeng