Antibacterial activity from the undecorated ZrNT against E. coli observed can be due to two reasons; zirconia nanoparticles have been demonstrated to have antibacterial properties, primarily due to the interaction of the positively charged zirconium ions with a negatively charged bacteria (E. coli) cell walls which can potentially result in the rupturing of the bacterial wall and ultimately cell death . This holds for the undecorated ZrNT and the release of zirconium ions was confirmed via ICP -MP Figure . Secondly; recent studies have shown that nanoscale patterning can induce the behavior of bacteria on surfaces in terms of ordering and orientation hence even without decoration with an antibacterial agent the geometrical morphology of nanotube can cause an antibacterial effect .