Compact Raman Imaging System Detects Subtle Tumor Signals

Accurate cancer diagnosis often depends on labor-intensive tissue staining and expert pathological review, which can delay results and limit access to rapid screening. These conventional methods also make it difficult to perform molecular imaging outside specialized laboratories. Detecting cancer-related molecular changes earlier and more efficiently remains a major challenge in clinical care. Researchers have now demonstrated a compact imaging approach that can rapidly distinguish tumor tissue from healthy tissue by detecting extremely weak molecular signals.

Researchers at Michigan State University’s Institute for Quantitative Health Science and Engineering (IQ, East Lansing, MI, USA) have designed a compact Raman imaging system capable of detecting very faint signals from surface-enhanced Raman scattering nanoparticles that bind to tumor markers. The system combines a swept-source laser, which varies wavelength during scanning, with a superconducting nanowire single-photon detector. This architecture improves light collection efficiency, reduces noise, and supports future miniaturization for clinical use.

The researchers validated the system by comparing its performance with that of a commercial Raman imaging platform. The new setup detected Raman signals approximately four times weaker than those measurable with existing systems. Experiments showed that the detector could reliably identify signals at femtomolar concentrations. The study describing the system and its validation was published in Optica.

To assess biological relevance, the team tested nanoparticles coated with hyaluronan acid, which targets CD44 proteins commonly expressed on tumor cells. Imaging experiments were performed on cultured breast cancer cells, mouse tumor models, and healthy tissues. Strong Raman signals were consistently observed in tumor samples, while a minimal background signal appeared in healthy tissue. These results demonstrated a clear tumor-versus-normal contrast.

The system could serve as a rapid screening tool to support earlier cancer detection, improve biopsy accuracy, and assist intraoperative decision-making. Its compact, fiber-coupled design may enable portable or bedside molecular imaging devices. Future work will focus on increasing imaging speed, expanding validation across cancer types, and enabling multiplexed detection of multiple biomarkers. These advances could help reduce diagnostic delays and support less invasive monitoring of disease progression.

“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,” said research team leader Zhen Qiu. “Ultimately, such advances could enhance patient outcomes and reduce diagnostic delays, accelerating the path from detection to treatment.”

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