Compact Raman Imaging System Differentiates Tumor and Normal Tissue

A new compact Raman imaging system has been developed that can distinguish cancerous from normal tissue by detecting faint signals. Designed to sense light from surface‑enhanced Raman scattering (SERS) nanoparticles that attach to tumor markers, the system could provide a faster and simpler way to screen for cancer and make molecular imaging more practical beyond laboratory settings.

“Traditional methods for cancer-related diagnosis are time-consuming and labor-intensive because they require staining tissue samples and having a pathologist look for any abnormalities,” said Zhen Qiu from Michigan State University’s Institute for Quantitative Health Science and Engineering. “While our system would not immediately replace pathology, it could serve as a rapid screening tool to accelerate diagnosis.”

In a paper in Optica, Qiu and colleagues demonstrated that their system can detect Raman signals roughly four times weaker than those measurable with a comparable commercial instrument. The sensitivity was achieved by pairing a swept‑source laser, which changes wavelength during scanning, with a superconducting nanowire single‑photon detector (SNSPD), an extremely sensitive device for capturing faint light signals. “This technology could eventually enable portable or intraoperative devices that enable clinicians to detect cancers at earlier stages, improve the accuracy of biopsy sampling and monitor disease progression through less invasive testing,” Qiu said.

SNSPDs operate by using a superconducting wire to detect single photons, allowing very weak signals to be recorded with low noise and high speed. By combining this advanced detector with a swept‑source Raman design that replaces a camera and collects light more efficiently, the group produced a compact, fiber‑coupled setup that supports miniaturization and potential clinical use.

The system was tested using SERS nanoparticles coated with hyaluronan acid, which promotes binding to CD44, a protein found on many tumor cells. In solutions and biological samples—including cultured breast cancer cells and mouse tissues—the device achieved femtomolar sensitivity. “The SERS signals were strongly concentrated in tumor samples, with only minimal background detected in healthy tissue,” said Qiu. The researchers now aim to enhance system speed using alternative lasers and explore multiplexed detection of multiple cancer biomarkers.