Blood Test Spots Cancer Before Scans Using DNA, Lasers and Gene Editing

Catching Cancer at Its Earliest Whisper

Catching cancer early is the single biggest factor in survival — but current blood tests often lack the sensitivity to detect tumours before they're visible on scans. Now researchers have built a sensor so sensitive it can pick up vanishingly small concentrations of cancer biomarkers in a simple blood sample.

The technology is a convergence of three cutting-edge fields. DNA tetrahedrons — tiny pyramid-shaped structures self-assembled from DNA strands — precisely position quantum dots at nanometre-scale distances above a molybdenum disulfide surface. When a cancer biomarker is present, CRISPR's Cas12a protein is activated and cuts the DNA tethers, releasing the quantum dots and creating a measurable change in a light signal.

"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," said lead researcher Han Zhang.

Key Facts

• Uses DNA tetrahedrons, CRISPR Cas12a, and quantum dots on MoS₂ surface
• Detection method: second harmonic generation (SHG)
• Detects biomarkers at concentrations far below current clinical thresholds
• Published by Optica, February 2026

Why This Matters

Early cancer detection saves lives, but most screening methods require the cancer to grow large enough to be visible on imaging. A blood test with this level of sensitivity could enable routine screening at annual checkups, catching cancers months or years earlier than current methods allow.

What We Don't Know Yet

This is a proof-of-concept sensor. Clinical validation in large patient populations is needed. False positive rates, specificity across different cancer types, and cost of quantum dot components are all unknowns. The gap between lab sensitivity and real-world clinical utility is historically large in diagnostics.

Sources: Optica · ScienceDaily