Scientists have developed a light-based sensor that can identify tiny amounts of cancer biomarkers in blood samples, potentially enabling earlier detection than traditional scans. The technology combines DNA nanostructures, CRISPR, and quantum dots to produce a clear signal from just a few molecules. Tests on lung cancer patient serum showed promising results at sub-attomolar levels.
Researchers at Shenzhen University in China have created an innovative sensor for detecting cancer biomarkers at extremely low concentrations in blood. Published in the journal Optica, the device uses second harmonic generation (SHG), a process where light is converted to half its wavelength on a molybdenum disulfide (MoS₂) surface. This approach avoids the need for chemical amplification, simplifying the detection process.
The system incorporates DNA tetrahedrons—pyramid-shaped nanostructures—to position quantum dots precisely near the MoS₂. These quantum dots enhance the optical field and amplify the SHG signal. CRISPR-Cas12a technology targets specific biomarkers; upon detection, it cleaves DNA strands holding the quantum dots, causing a measurable decrease in the SHG signal. This method minimizes background noise, allowing detection without additional steps that add time and cost.
"Our sensor combines nanostructures made of DNA with quantum dots and CRISPR gene editing technology to detect faint biomarker signals using a light-based approach known as second harmonic generation (SHG)," said Han Zhang, the research team leader. The platform detected miR-21, a microRNA linked to lung cancer, in human serum samples from patients. It showed high specificity, ignoring similar RNA strands and responding only to the target.
"The sensor worked exceptionally well, showing that integrating optics, nanomaterials and biology can be an effective strategy to optimize a device," Zhang added. The technology could extend to detecting viruses, bacteria, toxins, or Alzheimer's biomarkers. Future plans include miniaturizing the system for portable use in clinics or remote areas, potentially allowing routine blood tests to monitor disease progression or treatment efficacy more frequently than imaging.
"For early diagnosis, this method holds promise for enabling simple blood screenings for lung cancer before a tumor might be visible on a CT scan," Zhang noted. This could improve survival rates and reduce healthcare costs by facilitating earlier interventions.
