A newly developed CRISPR-based light sensor can pick up the slightest traces of cancer from just a single drop of blood.
Researchers have developed a sophisticated light-driven sensor that can detect extremely low levels of cancer biomarkers in the bloodstream. In the future, this technology could enable physicians to spot early signs of cancer and other illnesses through a simple routine blood test.
Challenges of Detecting Early-Stage Cancer Biomarkers
Biomarkers—including proteins, DNA fragments, and other molecules—can reveal whether cancer is present, how it is advancing, or an individual’s risk level. However, in the earliest stages of disease, these indicators appear in minuscule quantities, making them challenging to detect.
“Our sensor integrates DNA-based nanostructures with quantum dots and CRISPR gene-editing technology to capture faint biomarker signals using a light-based method called second harmonic generation (SHG),” explained research team leader Han Zhang of Shenzhen University in China. “If proven effective, this strategy could simplify treatment, improve survival outcomes, and reduce overall healthcare expenses.”
In Optica, the high-impact research journal published by Optica Publishing Group, Zhang and his team reported that their sensor identified lung cancer biomarkers in patient samples at sub-attomolar concentrations. In other words, it produced a distinct signal even when only a few molecules were present. Because the platform is programmable, it could potentially be tailored to detect viruses, bacteria, environmental pollutants, or biomarkers associated with diseases such as Alzheimer’s.
“For early detection, this technique could make it possible to conduct straightforward blood tests for lung cancer before a tumor becomes detectable on a CT scan,” Zhang said. “It may also support more personalized treatment strategies by enabling physicians to track a patient’s biomarker levels daily or weekly to evaluate how well a drug is working, instead of waiting months for imaging results.”
Optical Sensing Technology Without Signal Amplification
Most existing biomarker detection techniques depend on chemical amplification to magnify extremely weak molecular signals—a step that can increase time, complexity, and expense. The researchers set out to create a direct detection approach that eliminates the need for these additional procedures.
The new system is based on second harmonic generation (SHG), a nonlinear optical phenomenon in which incoming light is converted into light with half its original wavelength. In this setup, SHG occurs on the surface of a two-dimensional semiconductor known as molybdenum disulfide (MoS₂).
To precisely control the signal, the scientists employed DNA tetrahedrons—tiny pyramid-like nanostructures made entirely of DNA—to place quantum dots at carefully measured distances from the MoS₂ surface. These quantum dots enhance the local optical field, thereby amplifying the SHG response.
The researchers then integrated CRISPR-Cas gene-editing technology to detect specific biomarkers. When the Cas12a protein recognizes its target, it cleaves the DNA strands that hold the quantum dots in place, leading to a measurable drop in the SHG signal. Because SHG produces minimal background noise, the system can identify extremely low concentrations of biomarkers with remarkable sensitivity.
“Rather than treating DNA solely as a biological material, we use it as programmable building blocks to assemble our sensor components with nanometer-scale accuracy,” Zhang explained. “By pairing nonlinear optical sensing—which significantly reduces background interference—with an amplification-free design, our approach achieves a unique combination of speed and precision.”
Promising Results in Lung Cancer Sample Testing
To assess its effectiveness, the team targeted miR-21, a microRNA associated with lung cancer. After verifying detection in a controlled buffer solution, they evaluated the sensor using serum samples from lung cancer patients, replicating the conditions of real-world blood tests.
“The sensor performed exceptionally, demonstrating that combining optics, nanomaterials, and biological components can effectively enhance device performance,” said Zhang. “It was also highly selective, ignoring other similar RNA strands and detecting only the lung cancer biomarker.”
The next goal is to miniaturize the optical system. The researchers aim to create a compact, portable device that could be used at the bedside, in outpatient clinics, or in remote areas with limited healthcare access.
Read the original article on: SciTechDaily
Read more: Researchers Found a New Way to Stop Pain Nerves From Spreading into The Spine
Leave a Reply