Engineers report advances in rapid cancer detection and monitoring

Size is important when it comes to detecting cancer. Traditional diagnostic imaging cannot detect tumors smaller than a certain size, which misses early detection and treatment opportunities. Circulating tumor exosomes are particularly small cancer biomarkers and are often overlooked. These nanovesicles are composed of molecules that reflect the parent cell. However, because they are small (about 30-150 nm in diameter) and complex, accurate detection of biomarkers carrying exosomes with molecular specificity is elusive.

So far, Wei-Chuan Shih, a professor of electrical and computer engineering at the University of Houston, Karen Institute of Technology, reports: IEEE sensor journal.

“This study found a strong synergistic effect of arrayed radiation coupling and substrate undercuts for high-performance biosensing in the visible light spectrum, where high-quality, low-cost silicon detectors are readily available point-of-point. For the first time, it shows that it enables care applications. ” “As a result, the index of refraction sensitivity increased from 207 nm / RIU to 578 nm / RIU, which greatly improved the sensitivity.”

Technically speaking, Shih electric field It provides access to an enhanced electric field that is otherwise buried around the nanodisc. Nanodiscs are antibody-functionalized artificial nanostructures that help capture molecularly specific exosomes.

“Report a radiated coupling array Gold nanodisc On an invisible substrate (AGNIS) as label-free ( Fluorescent label), Cost-effective and high-performance platform for molecule-specific Exosomes Biosensing. AGNIS substrates are manufactured by wafer-scale nanosphere lithography without the need for expensive lithography, “Shih said.

This allows rapid screening of exosome surface proteins for diagnosis and biomarker discovery. As an example, Shih showed that multiple surface antigens (CD9, CD63, and CD81) are more abundant in cancer-derived exosomes than those from normal cells.

Current exosome profiling is mainly DNA sequencing technology, Flow cytometry, Or enzyme-linked immunosorbent assay (ELISA), involves advanced sample preparation procedures and requires labeling and amplification. All of these processes are labor intensive and costly. Shih’s goal is to amplify the signal by developing label-free technology.

“By decorating the surface of gold nanodiscs with various antibodies (CD9, CD63, CD81, etc.), label-free exosome profiling has been shown to increase expression of all three surface proteins in cancer-derived exosomes. It was done, “says Shih. “Sensitivity to detect exosomes is in the range of 112-600 (exosomes / μL), which is sufficient for many clinical applications.”