The rapid emergence of superbugs which
are resistant to existing antibiotics is becoming a huge global threat
to public health, which demands the discovery of next-generation antibacterial
agents for combating superbugs. Herein, we report the design of a
two-dimensional (2D) reduced graphene oxide (r-GO) and one-dimensional
(1D) WO3 nanowire-based photothermal–photocatalytic
heterostructure for combating multiantibiotic-resistant Salmonella DT104, carbapenem-resistant Enterobacteriaceae
Escherichia coli, and methicillin-resistant Staphylococcus aureus superbugs. In the presence of near-infrared (NIR) light, due to
the generation of electrons and holes, the WO3-based heterostructure
generates reactive oxygen species by photocatalytic reaction from
water and oxygen, which kills superbugs. To enhance the photocatalytic
superbug killing efficiency, r-GO has been used for suppressing the
recombination of the photoinduced electron–hole pairs. Reported
data show that NIR light-driven synergistic photocatalytic–photothermal
processes can be used for 100% degradation of methylene blue using
a heterostructure-based catalyst, and the photodegradation rate for
the heterostructure is much better than the literature data for different
types of WO3/GO-based nanocomposites. Experimentally, time-dependent
antibacterial efficiency data reveals that the heterostructure can
destroy 100% superbugs within 30 min of light exposure via a synergistic
photothermal and photocatalytic mechanism, whereas the WO3 nanowire can kill around 35% superbugs only via photocatalytic action
only and r-GO can kill 25% superbugs via photothermal action even
after 30 min of exposure to light. Systematic time-dependent microscopy
and spectroscopy studies reveal that the excellent antisuperbug activities
for heterostructures are due to membrane damage, ATP, and DNA/RNA
breakage. For possible real-life applications, sun light-based superbug
inactivation shows 100% inactivation possible within 250 min of light
exposure using 12 mg/mL heterostructures. The reported sun light-driven
killing of superbugs provides a simple and versatile platform to combat
drug-resistant superbugs.