IL6 and COVID-19: A biosensor, consisting of a paper immunosensor capable of generating intense colorimetric signals and communicating with a smartphone aimed at detecting severe cases of COVID-19, has been proposed by Adrover-Jaume and colleagues.49 They have proposed the sensor as a diagnostic biomarker for COVID-19 to detect the ultra-low concentrations of interleukin 6 (IL-6) in blood samples of patients.