Detection of Staphylococcal Enterotoxin A (SEA) using a sensitive nanomaterial-based electrochemical aptasensor

An electrochemical aptasensor was developed for SEA detection based on the application of chemically reduced graphene oxide and gold nano-urchins for enhancing sensitivity. The complex of the Staphylococcal Enterotoxin A (SEA) molecule and its specific aptamer on the nanomaterial-modified electrode is triggering the aptamer to be detached from the electrode surface and make a difference in the peak current of Differential pulse voltammetry. The fabrication process was confirmed using Cyclic Voltammetry, electrochemical impedance spectroscopy, and Scanning Electron Microscope imaging. As result, the limit of detection was 7.6 fM and the linear range was 25.0–950.0 fM of SEA. The selectivity assessment revealed the high specificity of the aptasensor towards SEA molecules compared to other similar toxin molecules and proteins. Moreover, the functionality of the developed system was tested successfully in spiked real samples of milk and meat as food samples and human serum as a clinical sample. These samples were also tested by a commercial ELISA kit of SEA to compare the results with the aptasensor. The test revealed that the recovery percentages and standard deviation of the aptasensor are superior to the ELISA kit. Therefore, the electrochemical aptasensor can be suggested for being used in food technologies and clinics to detect SEA toxin. [Display omitted] •An electrochemical aptasensor was developed for detection of Staphylococcal Enterotoxin A (SEA).•Reduced graphene oxide and gold nanourchins were used to modify the electrode surface.•The limit of detection was 7.6 fM and the linear range was 25.0–950.0 fM of SEA.