KN-93 is widely used in biomedical research as a selective inhibitor of calcium/calmodulin-dependent protein kinase II (CaMKII). It is commonly applied in studies related to cellular signaling pathways, particularly in the investigation of cardiac function, neuronal activity, and synaptic plasticity. Researchers use KN-93 to probe the role of CaMKII in processes such as heart rhythm regulation, where its inhibition can suppress arrhythmias, and in the brain, where it helps examine mechanisms underlying learning and memory. Due to its ability to cross cell membranes, KN-93 is effective in both in vitro and in vivo experimental models, making it a valuable tool for understanding CaMKII-dependent physiological and pathological conditions.