Bacterial
colonization poses significant health risks, such as
infestation of surfaces in biomedical applications and clean water
unavailability. If maintaining the surrounding water clean is a target,
developing surfaces with strong bactericidal action, which is facilitated
by bacterial access to the surface and mixing, can be a solution.
On the other hand, if sustenance of a surface free of bacteria is
the goal, developing surfaces with ultralow bacterial adhesion often
suffices. Here we report a facile, scalable, and environmentally benign
strategy that delivers customized surfaces for these challenges. For
bactericidal action, nanostructures of inherently antibacterial ZnO,
through simple immersion of zinc in hot water, are fabricated. The
resulting nanostructured surface exhibits extreme bactericidal effectiveness
(9250 cells cm
–2
h
–1
) that eliminates
bacteria in direct contact and also remotely through the action of
reactive oxygen species. Remarkably, the remote bactericidal action
is achieved without the need for any illumination, otherwise required
in conventional approaches. As a result, ZnO nanostructures yield
outstanding water disinfection of >99.98%, in the dark, by inactivating
the bacteria within 3 h. Moreover, Zn
2+
released to the
aqueous medium from the nanostructured ZnO surface have a concentration
of 0.73 ± 0.15 ppm, markedly below the legal limit for safe drinking
water (5–6 ppm). The same nanostructures, when hydrophobized
(through a water-based or fluorine-free spray process), exhibit strong
bacterial repulsion, thus substantially reducing bacterial adhesion.
Such environmentally benign and scalable methods showcase pathways
toward inhibiting surface bacterial colonization.