The semiconductor sensor that detects antigen molecules by capturing them on the surface of a nanosheet film. (Credit: Toyohashi University of Technology)

Measuring devices that perform disease tests simply and quickly from small amounts of blood, urine, saliva, and other bodily fluids are extremely important for accurate diagnosis and verifying the effectiveness of therapeutic treatments. PSA of therapeutic treatments. PSA is a marker that increases in the blood as a result of prostate cancer. Marker screening of saliva is also carried out as a less-invasive form of cancer risk testing. A microscale testing chip that uses flexibly deforming nanosheets is formed using semiconductor micromachine technology to determine the presence or absence of disease.

The research team changed the materials used from the conventional method, and instead adopted a method of depositing the functional layer by chemical vapor deposition. As a result, a thinner, more uniform, and less-degraded sensor chip was created. Using the biosensors developed on this occasion, the team conducted an experiment detecting prostate cancer biomarkers, and succeeded in detecting 100 attograms molar concentration contained in one milliliter of fluid.

This lower limit detection concentration is comparable to that of large testing devices using labeling agents and can be hoped to be applied in ultrasensitive testing with portable-scale testing devices. Furthermore, since it is possible to detect how nanosheets deform by adsorption of molecules in real time, it is possible to detect disease-derived molecules faster than in comparison with testing equipment using labeling agents.

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