Scientists have created an optical biosensor that identifies cancer DNA in blood samples in 20 minutes, achieving almost perfect accuracy in distinguishing healthy individuals from cancer patients.
The device, developed at the Korean Institute of Materials Science, detects methylated DNA (chemical changes that occur when cancer develops) at a concentration of 1,000 times lower than the current method. In a test with 60 patients with colorectal cancer, the sensor correctly identified the presence of cancer 99% of the time.
How technology works
The plasma materials used by biosensors have expanded the optical signal of DNA molecules by more than 100 million times. When lasers hit these materials in the presence of cancer DNA, they create electromagnetic “hot spots” that enhances the usually weak molecular signal.
The sensor can detect methylated DNA in 25 graphical patterns per milliliter, equivalent to 1/25,000 sugar particles found in water droplets.
Key Benefits Compared with Current Methods
- Only 100 shimmering blood (about 2 drops)
- Provides 20 minutes with hours or days results
- No complicated sample preparation required
- Distinguish between cancer stages I to IV
- Achieving 100% sensitivity and 98.3% specificity
The technology uses a process called plasma molecular entrainment (PME). The gold nanostructures capture DNA molecules while other gold layers are planted around them, creating the best conditions for signal amplification.
Machine Learning Improves Accuracy
The artificial intelligence algorithm analyzes the light pattern to determine the methylation level. Logistic regression models investigate specific wavelengths where methylated DNA produces different signals, especially at 1,482 cm⁻⁻ on the Raman spectrum.
The AI system quantifies the overall methylation level – the total percentage of methylated DNA in the entire genome. Cancer patients showed lower methylation (12.7%) (15.9%) compared to healthy individuals, reflecting a phenomenon known as global methylation associated with tumor development.
Clinical manifestations details
The researchers tested serum samples from 40 patients with colorectal cancer at all stages and in 20 healthy control groups. In addition to simple detection, the sensor differentiates the cancer stage with significant precision:
- Stage I: 14.4% methylation (detection sensitivity is 86.7%)
- Stage 2: 13.1% methylation (80% detection sensitivity)
- Stage 3: methylation 12.3% (90% detection sensitivity)
- Stage 4: 11.2% methylation (93.3% detection sensitivity)
Reduced methylation levels are associated with cancer progression, thus providing insights into disease severity. Five times cross validation confirmed the reliability of the model, with accuracy ranging from 81.5% to 93.8% in different patient groups.
Technological innovation: particle gap
High resolution imaging reveals a crucial detail: the sensor creates a 2.52-nanometer nanoscale gap between gold particles in the presence of DNA. These gaps accurately generate strong electromagnetic fields, at the DNA molecule position, maximizing signal enhancement.
The team used electron energy loss spectroscopy to verify the mechanism, which shows nitrogen atoms of DNA evenly distributed from the sensor surface. Real-time monitoring captures the signal amplification process for more than 280 seconds, as the gold structure forms around DNA.
Future applications
Although initially developed for colorectal cancer, the platform may detect a variety of cancers and diseases involving changes in DNA methylation. Researchers envision applications in hospitals, screening centers and even home diagnostic kits.
“This technology is a next-generation diagnostic platform that not only enables early cancer detection, but also predicts prognosis and monitors therapeutic responses,” said Dr. Ho Sang Jung, a senior researcher and project leader at Kims.
The ability of sensors to be used with original serum samples eliminates the time-consuming DNA extraction steps required by conventional methods. Combining its compact design and rapid analysis, this will position the technical aspects of point-of-care testing in clinical settings.
The study appears in the May 2025 issue Advanced Science.
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