To provide direct cause of bacterial cell death on the bactericidal activity of CoMnCuZnAg-IOC, the morphological characteristics of remnant E. coli bacteria adhered on the coatings were examined by SEM (Figure ). The adhered E. coli cells on the uncoated ITO have intact rod-like morphology with a smooth cell membrane (marked with red dashed line) and flagellar filaments, (marked by a yellow arrow), characterizing the normal growth of bacteria on this surface (Figure ). In stark contrast, the E. coli cells attached on the five-metal coating show the round or irregular shapes (orange arrows in Figure ), which are smaller (average of ~0.15 µm in diameters) compared to those in Figure (average of ~3.5 µm), as well as defective cell membrane and wrinkled surface.