Overview:
Details:
The research team is developing a micro sensor chip that checks for diseases using a flexibly deformable nanosheet made using semiconductor micromachining technology. First, an antibody that catches the targeted antigens is fixed onto the nanosheet, and deformations to a thin film caused by electric repulsions among the adhered antigens is measured. To improve sensitivity to the point where the membrane that the antigens adhere to becomes thin and soft, organic nanosheets two-times softer than semiconductor silicon are used. This is expected to improve sensor sensitivity to a magnitude twice that of conventional silicon-based sensors. In addition, development is continuing on signal detection technology that uses a smartphone camera to detect nanosheet deformation.
With this sensor, which is designed for sensitive changes in adhesion of biomolecules, the antibody must be fixed to the nanosheet in advance in order to capture the antigen, and issues related to film degradation can make this process difficult. The research team optimized density for antibodies to adhere to a nano membrane with adjustable thickness, creating a biosensor that detects only antigens with specifically high sensitivity. Moreover, since it is possible to detect deformation to the nano sheet caused by adhered molecules in real time, the technology is expected to allow for quick detection of disease-derived molecules. The biosensor developed in this project was used in an experiment to detect albumin, a protein contained in blood. The experiment successfully detected one femtogram (15 attomoles in molar concentration) of antigen contained in one milliliter. With the minimum detection limit almost equivalent to that of large-scale detection devices that use labeling agents, this device is expected to allow for ultra-sensitive detection on a portable scale.
Future Outlook:
Going forward, the research team plans to conduct trials using semiconductor sensors to detect markers for severe symptoms of COVID-19 infection. In addition to blood detection, chemical sensors are being developed to detect odor and chemical substances. We believe we can contribute to an IoT-based society by making new, small-scale sensor devices a reality. Replacing the probe molecule on the surface of our nanosheet, the technology can be used to detect viruses while also detecting a variety of biomarkers. By making these biosensors common in society, we aim to contribute to telemedicine, allowing doctor diagnoses to be performed from home.
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Reference:
This research was conducted with grants from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) Scientific Research Fund (Basic Research (B)), the Japan Science and Technology Agency (JST) PRESTO Creation of Innovative Nanoelectronics Combining Materials, Devices, and Systems, and a Future Challenge 2050 grant from the New Energy and Industrial Technology Development Organization (NEDO).
Biosensors and Bioelectronics