Aptamer selection of radiation-sensitive protein p21 and electrical impedance detection-based applications in radiation dose assessment

Radiation dose assessment is the main basis for the diagnosis of acute radiation sickness. At present, there is a lack of rapid and portable dose assessment methods, which has an important impact on the rapid diagnosis and precise treatment of radiation accident patients and nuclear practitioners. We selected and obtained specific aptamers for radiation-sensitive protein p21 protein by the magnetic cross-linking precipitation (MCP)-SELEX procedure. The aptamer has a high affinity for binding to the p21 protein and its K_d value is 2.21 × 10^-7 mol/L. We subsequently established a new method for radiation dose assessment of an electrochemical impedance (EIS) aptasensor with screen-printed electrode chips. There was a good dose-effect relationship between the p21 protein expression level in PBMCs in human peripheral blood detected by this method within the dose range of 0-10 Gy, and detection limit of radiation dose is 0.38 Gy (LOD, S/N = 3). This dose range covers the diagnostic range of acute radiation sickness in the bone marrow. This method is not only portable but also fast, saving hours to days compared with the previous dose assessment method based on radiation sensitive protein. It can be applied to the rapid and portable diagnosis of acute radiation sickness.