Another fascinating model that consists of a Tetrahedral DNA (TDs) aptamer built in HCR and Au/Ti3C2-MXene amplified units on EC/ECL biosensors detected cTnI levels in blood samples of COVID-19 critical cases with LODs of 0.04 or 0.1 fM (Sandoval et al., 2020). Here, TNNI3 is linked to COVID-19.