Scientists at the Universidad Carlos III de Madrid (UC3M) have developed the first photo-electrochemical aptasensor that detects the SARS-CoV-2 virus in a saliva sample. This sensor, which uses aptamers (a type of artificial antibody), is more sensitive that antigen-based sensors and detects the virus more quickly and cheaply than PCR tests. These new devices can be incorporated into portable diagnostic systems and are easy to use.