Scientists have developed a novel light-based sensor capable of detecting minuscule amounts of cancer biomarkers in blood samples. This advancement could facilitate early detection of cancer and other diseases through routine blood tests. Biomarkers, which include proteins and DNA fragments, indicate the presence and progression of cancer, but they are often present in very low concentrations during the early stages of disease, complicating detection with traditional methods.
The research team, led by Han Zhang from Shenzhen University in China, utilized a combination of nanostructures made from DNA, quantum dots, and CRISPR gene editing technology to create a sensor that employs a technique known as second harmonic generation (SHG). This method allowed the detection of lung cancer biomarkers at sub-attomolar concentrations, producing clear signals even with minimal molecules present. The programmable nature of the sensor means it could potentially be adapted for identifying various viruses, bacteria, and biomarkers associated with conditions like Alzheimer's disease.
Current biomarker tests often require chemical amplification, which adds complexity and cost. The new sensor aims to eliminate this need by directly detecting signals using SHG, which occurs on a two-dimensional semiconductor known as molybdenum disulfide (MoS₂). The researchers constructed DNA tetrahedrons to hold quantum dots at precise distances from the semiconductor surface, enhancing the SHG signal.
In testing, the sensor successfully identified the miR-21 biomarker associated with lung cancer in human serum samples, indicating its potential effectiveness in real-world applications. The researchers plan to further miniaturize the optical system to create a portable version suitable for bedside use in various medical settings.