2023-07-24 09:06:01
Invisibly small feelers are set up like chess pieces on a protein lattice. Underneath are tiny transistors. If they perceive inflammatory factors, for example, the charge of the units changes and current becomes measurable, said the Viennese pioneer of synthetic biology, Uwe Sleytr of the APA. With such bioelectrosensors one might detect cancer, inflammation and viral infections in body fluids in the future. The study was published in the journal Science Advances.
Flexible mini sensor for future “immediate diagnostics close to the patient” (symbol image)
Sleytr, who conducts research at the Department of Bionanosciences at the University of Natural Resources and Life Sciences (Boku) Vienna, developed the sensors together with the bioengineer Shuguang Zhang and the electronics expert Tomas Palacios from the Massachusetts Institute of Technology (MIT) in Cambridge (USA) with the collaboration of Andreas Breitwieser. Each brought a very specific technology to it, Sleytr explained.
Bioengineer Zhang reversed the polarity of the feelers (receptor molecules on cell surfaces), which actually need the “fatty” environment of a biological lipophilic (fat-loving) membrane, so that they now prefer an aqueous environment. To do this, he exchanged three lipophilic amino acids (building blocks of proteins) for three water-loving ones. Thus, they can be used well in the biotechnical sensor system.
Sleytr contributed the uniform protein lattice called the S-layer. The receptor molecules were attached densely and regularly to this. The protein molecules for this originally come from the cell surfaces of spherical bacteria (Lysinibacillus sphaericus). They form crystal lattices with fields each measuring 13 nanometers on each side (i.e. 13 billionths of a meter) like a chessboard, with one receptor on each. For comparison: a human hair is approximately 5,000 times thicker. “This is an incredibly stable layer where the receptors are so densely packed that there’s no space between them,” says Sleytr. This would prevent other molecules from slipping in between and triggering an unwanted, non-specific signal.
predict metastasis
The S-layer together with the receptor molecules was applied to field-effect transistors developed by Tomas Palacios and his team. They consist of graphene, i.e. a carbon foil that is only one atom thick. These semiconductor components amplify the signals coming from the receptors so that current can be measured.
As a feasibility example, the researchers produced a sensor with the “CXCR4” receptor molecule. This is an immune system receptor. It binds a messenger substance called “CXCL12”, which is released during inflammation. “Monitoring blood levels of CXCL12 can provide important information regarding human immune responses in a variety of diseases such as multiple sclerosis and infections,” the researchers said in the paper. For at least 23 types of cancer, it would also be possible to predict metastasis formation and create more accurate prognosis for patients. “CXCR4 is also one of the co-receptors for HIV entry into T cells, enabling HIV diagnosis and monitoring for clinical management,” they wrote.
The sensors can be regenerated by washing them with an “acidic buffer solution” and can therefore be reused. They’re flexible and might be worn well on the skin or potentially as implants, Sleytr said. Above all, they might be used as “immediate diagnostics close to the patient” in hospital wards, practices of established physicians, pharmacies and emergency ambulances, so that the patient samples would not have to be sent to a central laboratory.
“Our goal is to develop the enabling technology for a future wearable device that we can integrate into cellphones and computers so that people can take a test at home and quickly find out if they should see a doctor,” the researchers said in a release from MIT.
Service: https://go.apa.at/mnZodrUp
(APA/red, Photo: APA/APA/AFP/THOMAS COEX)
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