Sensor Detects Cancer Biomarker in Urine – New Technology
Scientists have pioneered using a Chip-Based Optical Sensor to detect cancer biomarkers in urine. This new technology lays the biosensor’s groundwork which can improve the diagnosis and monitoring of diseases.
Very low levels of a cancer protein biomarker in a urine sample could be detected by this chip-based sensor with an integrated laser. Compared to other designs, this technology is much more sensitive and it could lead to inexpensive and non-invasive ways for detecting molecules that can indicate the progression or presence of a disease.
Sonia M. Garcia-Blanco, the research team leader from the University of Twente in the Netherlands said, “The methods for measuring biomarker levels available currently are sophisticated and expensive and it requires analysis and biopsies in specialized laboratories. Quicker ways and ultrasensitive detection of biomarkers panels are possible through this new technology we developed, which would let the doctors take timely decisions and improve the personalized diagnosis and treatment of cancer and other medical conditions.”
In a multi-institutional group of researchers funded by the H2020 European project GLAM (Glass multiplexed biosensor), the Optical Society (OSA) journal Optics Letters, showed that the new sensor is able to perform label-free detection of a protein linked with tumor development in human, S100A4 and it could perform this at clinically relevant levels.
Garcia-Blanco said, ” The point-of-care devices simultaneously screening for many diseases could be enabled by this biosensor. It makes an excellent option for clinical applications as it has a simple operation and it does not include any sensor operation or complicated sample treatments.”
The scientists say that this sensor has the potential to be used in non-biomedical applications also, for example, using it to detect different types of liquid mixtures or gases.
To detect cancer biomarker, a high-sensitivity sensor created
Specific molecules are detected by this new chip-based sensor by illuminating the sample with on-chip microdisk laser’s light. The frequency, or color of this laser light shifts in a detectable way when the light interacts with the biomarker of interest.
The scientists had to figure out the integration of a laser that could operate in a liquid environment for performing detection in the urine samples. When doped with ytterbium ions, the photonic material aluminum oxide can be made use for fabricating a laser that can emit wavelength range outside the light absorption band of water and could enable accurate biomarkers detection.
There are sensors that work on monitoring frequency shifts of lasers already available, but these are mostly found in such geometrics which is hard to integrate on small and disposable photonic chips. On a chip, aluminum oxide can be easily fabricated monolithically and it is compatible with standard electronic fabrication procedures, which means, the sensors can be manufactured on a large industrial scale.
Instead of using the non-lasing ring resonators that are used in other similar sensors, using a microdisk laser allows exceptional sensitivity. The resonances of passive ring resonators are much narrower than the lasing linewidth which gives rise to such sensitivity. At very low concentrations, this method will allow the detection of very small frequency shifts from biomarkers, once the noise sources like thermal noise are all eliminated.
Sensor Detects minute biomarker concentrations
To capture the biomarkers of interest in complex liquids like urine, after the development and application of a surface treatment, the scientists tested the new sensor with synthetic urine with known levels of biomarkers. S100A4 could be detected even at concentrations of 300 picomolar.
Garcia-Blanco said, “The potential of the platform for label-free biosensing is seen from the detection at this concentration range. Additionally, using developed technology, the detection module can be potentially made very simple, which would bring it one step closer to the final application outside of the laboratory.”
The researchers are working to use all the relevant signal generation components and optical sources onto the chip for making the device much more easier to operate. They are also trying to develop many coatings to allow parallel detection of many different biomarkers.
Author: Prathibha HC