New Sensor Uses Light to Detect Ultra-Low Levels of Disease Biomarkers

A research team has developed a novel sensor that uses light to detect extremely low concentrations of disease biomarkers in blood. The technology integrates DNA nanostructures, quantum dots, and CRISPR gene editing, and is designed to identify biomarkers without requiring complex amplification steps. It has already been demonstrated to detect a lung cancer biomarker in patient samples.

The sensor operates using a light-based technique called second harmonic generation (SHG), which occurs on the surface of a two-dimensional semiconducting material, molybdenum disulfide (MoS₂).

How the Technology Works

To enhance the SHG signal, researchers used self-assembled DNA nanostructures, shaped like pyramids, to position quantum dots at precise distances from the MoS₂ surface.

For specific detection, the sensor employs the CRISPR-Cas12a protein. When Cas12a identifies a target biomarker, it cleaves the DNA structures tethering the quantum dots, resulting in a measurable decrease in the SHG signal. The research team, led by Han Zhang of Shenzhen University, stated that this design minimizes background noise, allowing for the detection of biomarkers at sub-attomolar concentrations.

Testing for Lung Cancer

In testing, the sensor was used to detect miR-21 (also referred to as miRNA-21), a microRNA biomarker associated with lung cancer. After confirming functionality in a buffer solution, the sensor successfully detected the biomarker in human serum samples from lung cancer patients, simulating a blood test. The researchers reported the sensor showed high specificity, detecting the target while ignoring similar RNA strands.

Broad Potential Applications

According to the researchers, the programmable nature of the sensor means it could be adapted to detect a range of targets.

The approach could simplify treatments, potentially improve survival rates, and reduce healthcare costs.

Potential targets include viruses, bacteria, environmental toxins, and biomarkers for other diseases such as Alzheimer's. The method is proposed for early lung cancer screening, potentially before tumors are visible on CT scans. It is also suggested it could enable more frequent monitoring of biomarker levels to assess drug efficacy during personalized treatment.

The Path Forward

The research team plans to miniaturize the optical components to create a portable device. The aim is for the device to be usable in various settings, including at the bedside, in clinics, or in remote locations with limited resources.

The research was published in the journal Optica.