This new blood test could detect cancer before it shows up on scans

 

Scientists have designed a powerful light based sensor capable of detecting extremely small amounts of cancer biomarkers in blood. The innovation could eventually allow doctors to identify early warning signs of cancer and other diseases through a routine blood draw.

Biomarkers such as proteins, fragments of DNA, and other molecules can signal whether cancer is present, how it is progressing, or a person's risk of developing it. The difficulty is that in the earliest stages of disease, these markers exist in extremely low concentrations, making them hard to measure with conventional tools.

"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 (SHG)," said research team leader Han Zhang from Shenzhen University in China. "If successful, this approach could help make disease treatments simpler, potentially improve survival rates and lower overall healthcare costs."

In Optica, Optica Publishing Group's journal for high-impact research, Zhang and his team reported that the device detected lung cancer biomarkers in patient samples at sub-attomolar levels. Even when only a few molecules were present, the system produced a clear and measurable signal. Because the platform is programmable, it could potentially be adapted to identify viruses, bacteria, environmental toxins, or biomarkers linked to conditions such as Alzheimer's disease.

"For early diagnosis, this method holds promise for enabling simple blood screenings for lung cancer before a tumor might be visible on a CT scan," said Zhang. "It could also help advance personalized treatment options by allowing doctors to monitor a patient's biomarker levels daily or weekly to assess drug efficacy, rather than waiting months for imaging results."

Amplification Free Optical Sensing Technology

Most current biomarker tests require chemical amplification to increase tiny molecular signals, which adds time, complexity, and expense. The researchers aimed to create a direct detection strategy that eliminates those additional steps.

The system relies on SHG, a nonlinear optical phenomenon in which incoming light is converted into light with half the wavelength. In this design, SHG takes place on the surface of a two dimensional semiconductor called molybdenum disulfide (MoS₂).

To precisely position the sensing components, the team built DNA tetrahedrons, which are small pyramid shaped nanostructures formed entirely from DNA. These structures hold quantum dots at carefully controlled distances from the MoS₂ surface. The quantum dots intensify the local optical field and boost the SHG signal.

CRISPR-Cas gene editing technology was then incorporated to recognize specific biomarkers. When the Cas12a protein detects its target, it cuts the DNA strands that anchor the quantum dots. This action triggers a measurable drop in the SHG signal. Because SHG produces very little background noise, the system can detect extremely low biomarker concentrations with high sensitivity.

"Instead of viewing DNA only as a biological substance, we use it as programmable building blocks, allowing us to assemble the components of our sensor with nanometer-level precision," said Zhang. "By combining optical nonlinear sensing, which effectively minimizes background noise, with an amplification-free design, our method offers a distinct balance of speed and precision."

Successful Lung Cancer Testing in Human Serum

To evaluate real world performance, the researchers focused on miR-21, a microRNA biomarker associated with lung cancer. After confirming that the device could detect miR-21 in a controlled buffer solution, they tested it using human serum from lung cancer patients to simulate an actual blood test.

"The sensor worked exceptionally well, showing that integrating optics, nanomaterials and biology can be an effective strategy to optimize a device," said Zhang. "The sensor was also highly specific -- ignoring other similar RNA strands and detecting only the lung cancer target."

The next goal is to shrink the optical system. The researchers aim to develop a portable version that could be used at the bedside, in outpatient clinics, or in remote areas with limited medical resources.

Journal Reference:

1. Bowen Du, Xilin Tian, Siyi Han, Yi Liu, Zhi Chen, Yong Liu, Linjun Li, Zheng Xie, Lingfeng Gao, Ke Jiang, Qiao Jiang, Shi Chen, Han Zhang. Sub-attomolar-level biosensing of cancer biomarkers using SHG modulation in DNA-programmable quantum dots/MoS2disordered metasurfaces. Optica, 2026; 13 (2): 319 DOI: 10.1364/OPTICA.577416 

Courtesy:

Optica. "This new blood test could detect cancer before it shows up on scans." ScienceDaily. ScienceDaily, 16 February 2026. <www.sciencedaily.com/releases/2026/02/260216044002.htm>. 

 

 

 

Scientists discover brain switches that clear Alzheimer’s plaques

 

Scientists at Karolinska Institutet in Sweden and the RIKEN Center for Brain Science in Japan have identified two brain receptors that help regulate the breakdown of amyloid beta, the protein that builds up in Alzheimer's disease. Their findings suggest it may be possible to develop future medications that are both safer and more affordable than today's antibody based treatments.

Alzheimer's disease is the leading cause of dementia and is marked by sticky clumps of amyloid beta (Aβ) forming plaques in the brain. Normally, an enzyme called neprilysin helps clear away Aβ. However, neprilysin activity declines with aging and during the progression of the disease. The research team discovered that two somatostatin receptors, SST1 and SST4, work together to control neprilysin levels in the hippocampus, a region essential for memory. The findings were published in the Journal of Alzheimer's Disease.

Boosting the Brain's Natural Defense System

The researchers conducted experiments using genetically modified mice and laboratory grown cells. When both SST1 and SST4 receptors were missing, neprilysin levels dropped. As a result, amyloid beta accumulated and the mice showed memory problems.

The team also tested a compound designed to activate these two receptors. In mice with Alzheimer's-like brain changes, stimulating SST1 and SST4 increased neprilysin levels, reduced amyloid beta buildup, and improved behavior. Importantly, the treatment did not cause serious side effects.

"Our findings show that the brain's own defence against amyloid beta can be strengthened by stimulating these receptors," says Per Nilsson, docent at the Department of Neurobiology, Care Sciences and Society, Karolinska Institutet.

Toward Safer and More Affordable Alzheimer's Drugs

Many of the most advanced Alzheimer's therapies currently rely on antibodies. While these treatments can target amyloid, they are extremely expensive and may trigger significant side effects in some patients.

"If we can instead develop small molecules that pass the blood-brain barrier, our hope is that we will be able to treat the disease at a significantly lower cost and without serious side effects," says Per Nilsson.

SST1 and SST4 belong to a large family of proteins known as G protein-coupled receptors. These receptors are common drug targets because they are well understood and often respond to medications that can be produced at lower cost and taken in pill form.

The project brought together researchers from Karolinska Institutet in Sweden, RIKEN Center for Brain Science in Japan, and several other international universities. Funding was provided by organizations including the Swedish Research Council, the Hållsten Research Foundation, the Alzheimer's Foundation and the private initiative Innovative ways to fight Alzheimer´s disease -- Leif Lundblad Family and others and RIKEN. The researchers report no conflicts of interest.

Journal Reference:

1. Per Nilsson, Karin Sörgjerd, Naomasa Kakiya, Hiroki Sasaguri, Naoto Watamura, Lovisa Johansson, Makoto Shimozawa, Satoshi Tsubuki, Zhulin Zhou, Raul Loera-Valencia, Risa Takamura, Misaki Sekiguchi, Aline Pegel, Stefan Schulz, Takashi Saito, Nobuhisa Iwata, Bengt Winblad, Takaomi C Saido. Somatostatin receptor subtypes 1 and 4 regulate neprilysin, the major amyloid-β degrading enzyme in brain. Journal of Alzheimer’s Disease, 2025; 109 (2): 651 DOI: 10.1177/13872877251392782 

Courtesy:

Karolinska Institutet. "Scientists discover brain switches that clear Alzheimer’s plaques." ScienceDaily. ScienceDaily, 17 February 2026. <www.sciencedaily.com/releases/2026/02/260215225555.htm>.