2 research outputs found
Recommended from our members
Gecko-Inspired Biocidal Organic Nanocrystals Initiated from a Pencil-Drawn Graphite Template
The biocidal properties of gecko skin and cicada wings have inspired the synthesis of synthetic surfaces decorated with high aspect ratio nanostructures that inactivate microorganisms. Here, we investigate the bactericidal activity of oriented zinc phthalocyanine (ZnPc) nanopillars grown using a simple pencil-drawn graphite templating technique. By varying the evaporation time, nanopillars initiated from graphite that was scribbled using a pencil onto silicon substrates were optimized to yield a high inactivation of the Gram-negative bacteria, Escherichia coli. We next adapted the procedure so that analogous nanopillars could be grown from pencil-drawn graphite scribbled onto stainless steel, flexible polyimide foil, and glass substrates. Time-dependent bacterial cytotoxicity studies indicate that the oriented nanopillars grown on all four substrates inactivated up to 97% of the E. coli quickly, in 15 min or less. These results suggest that organic nanostructures, which can be easily grown on a broad range of substrates hold potential as a new class of biocidal surfaces that kill microbes quickly and potentially, without spreading antibiotic-resistance genes
Bioinspired Photocatalytic Shark-Skin Surfaces with Antibacterial and Antifouling Activity via Nanoimprint Lithography
By combining antifouling
shark-skin patterns with antibacterial titanium dioxide (TiO<sub>2</sub>) nanoparticles (NPs), we present a simple route toward producing
durable multifunctional surfaces that decrease microbial attachment
and inactivate attached microorganisms. Norland Optical Adhesive,
a UV-crosslinkable adhesive material, was loaded with 0, 10, or 50
wt % TiO<sub>2</sub> NPs from which shark-skin microstructures were
imprinted using solvent-assisted soft nanoimprint lithography on a
polyÂ(ethylene terephthalate) (PET) substrate. To obtain coatings with
an exceptional durability and an even higher concentration of TiO<sub>2</sub> NPs, a solution containing 90 wt % TiO<sub>2</sub> NPs and
10 wt % tetraethyl orthosilicate was prepared. These ceramic shark-skin-patterned
surfaces were fabricated on a PET substrate and were quickly cured,
requiring only 10 s of near infrared (NIR) irradiation. The water
contact angle and the mechanical, antibacterial, and antifouling characteristics
of the shark-skin-patterned surfaces were investigated as a function
of TiO<sub>2</sub> composition. Introducing TiO<sub>2</sub> NPs increased
the contact angle hysteresis from 30 to 100° on shark-skin surfaces.
The hardness and modulus of the films were dramatically increased
from 0.28 and 4.8 to 0.49 and 16 GPa, respectively, by creating ceramic
shark-skin surfaces with 90 wt % TiO<sub>2</sub> NPs. The photocatalytic
shark-skin-patterned surfaces reduced the attachment of Escherichia coli by ∼70% compared with smooth
films with the same chemical composition. By incorporating as low
as 10 wt % TiO<sub>2</sub> NPs into the chemical matrix, over 95% E. coli and up to 80% Staphylococcus
aureus were inactivated within 1 h UV light exposure
because of the photocatalytic properties of TiO<sub>2</sub>. The photocatalytic
shark-skin-patterned surfaces presented here were fabricated using
a solution-processable and roll-to-roll compatible technique, enabling
the production of large-area high-performance coatings that repel
and inactivate bacteria