Impact of Bioinspired Nanotopography on the Antibacterial and Antibiofilm Efficacy of Chitosan

Tripathy, Abinash; Pahal, Suman; Mudakavi, Rajeev J.; Raichur, Ashok M.; Varma, Manoj M.; Sen, Prosenjit

doi:10.1021/acs.biomac.8b00200

Cited by 41 publications

(31 citation statements)

References 53 publications

(62 reference statements)

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“…The bactericidal effect of the nanostructures was discovered by studying natural nanostructured surfaces such as cicada wings, [11][12][13][14][15] dragony wings, 12,16,17 and gecko ngers. 18,19 Later it was discovered that articial nanostructured surfaces composed of inorganic materials, such Si 11,15,20,21 and carbon nanotubes (CNT), 22 and organic materials, [23][24][25][26] also have bactericidal properties. The bactericidal activity on a nanostructure originates from its physical instead of from its chemical properties; the cell membranes are stretched by the nanostructured surface, which causes cell break.…”

Section: Introductionmentioning

confidence: 99%

Adhesion and bactericidal properties of nanostructured surfaces dependent on bacterial motility

et al. 2020

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Section: Introductionmentioning

confidence: 99%

Adhesion and bactericidal properties of nanostructured surfaces dependent on bacterial motility

et al. 2020

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“…ZnO is known to exhibit antimicrobial efficacy [15][16][17][18][19], killing bacteria and prohibiting bacterial growth on its surface via release of Zn 2+ ions which solicit generation of reactive oxygen species (ROS). A number of naturally occurring surfaces bearing spiky nanotextures (e.g., cicada wings, dragonfly wings, and gecko skin) have been reported to exhibit bactericidal efficacy, attributed to puncturing or stretching of the bacterial membrane, although the detailed mechanisms remain to be fully understood [3,11,[73][74][75][76]. Hence, we suggest that the ZnO urchin surfaces could prevent bacterial growth by combining synergistically the inherent chemical activity of ZnO and the spiky morphology of the urchins that inhibit the bacteria from colonizing on the surface of the ZnO urchins [18,[77][78][79].…”

Section: Resultsmentioning

confidence: 99%

Facile Fabrication of Multifunctional ZnO Urchins on Surfaces

Tripathy

Wąsik

Sreedharan

et al. 2018

Colloids and Interfaces

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Functional ZnO nanostructured surfaces are important in a wide range of applications. Here we report the simple fabrication of ZnO surface structures at near room temperature with morphology resembling that of sea urchins, with densely packed, µm-long, tapered nanoneedles radiating from the urchin center. The ZnO urchin structures were successfully formed on several different substrates with high surface density and coverage, including silicon (Si), glass, polydimethylsiloxane (PDMS), and copper (Cu) sheets, as well as Si seeded with ZnO nanocrystals. Time-resolved SEM revealed growth kinetics of the ZnO nanostructures on Si, capturing the emergence of "infant" urchins at the early growth stage and subsequent progressive increases in the urchin nanoneedle length and density, whilst the spiky nanoneedle morphology was retained throughout the growth. ε-Zn(OH) 2 orthorhombic crystals were also observed alongside the urchins. The crystal structures of the nanostructures at different growth times were confirmed by synchrotron X-ray diffraction measurements. On seeded Si substrates, a two-stage growth mechanism was identified, with a primary growth step of vertically aligned ZnO nanoneedle arrays preceding the secondary growth of the urchins atop the nanoneedle array. The antibacterial, anti-reflective, and wetting functionality of the ZnO urchins-with spiky nanoneedles and at high surface density-on Si substrates was demonstrated. First, bacteria colonization was found to be suppressed on the surface after 24 h incubation in gram-negative Escherichia coli (E. coli) culture, in contrast to control substrates (bare Si and Si sputtered with a 20 nm ZnO thin film). Secondly, the ZnO urchin surface, exhibiting superhydrophilic property with a water contact angle ∼ 0 • , could be rendered superhydrophobic with a simple silanization step, characterized by an apparent water contact angle θ of 159 • ± 1.4 • and contact angle hysteresis ∆θ < 7 • . The dynamic superhydrophobicity of the surface was demonstrated by the bouncing-off of a falling 10 µL water droplet, with a contact time of 15.3 milliseconds (ms), captured using a high-speed camera. Thirdly, it was shown that the presence of dense spiky ZnO nanoneedles and urchins on the seeded Si substrate exhibited a reflectance R < 1% over the wavelength range λ = 200-800 nm. The ZnO urchins with a unique morphology fabricated via a simple route at room temperature, and readily implementable on different substrates, may be further exploited for multifunctional surfaces and product formulations.

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“…A number of naturally occurring surfaces bearing spiky nanotextures (e.g. cicada wing, dragonfly wing, and gecko skin) have been reported to exhibit bactericidal efficacy, attributed to puncturing or stretching of the bacterial membrane, although the detailed mechanisms remain to be fully understood 3,11,[68][69][70][71] .…”

Section: Resultsmentioning

confidence: 99%

Facile Fabrication of Multifunctional ZnO Urchins on Surfaces

Tripathy¹,

Wąsik²,

Sreedharan³

et al. 2018

Preprint

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Functional ZnO nanostructured surfaces are important in a wide range of applications. Here we report facile fabrication of ZnO surface structures at near room temperature with morphology resembling that of sea urchins, with densely packed, μm-long, tapered nanoneedles radiating from the urchin centre. The ZnO urchin structures were successfully formed on several different substrates with high surface density and coverage, including silicon (Si), glass, polydimethylsiloxane (PDMS), and copper (Cu) sheets, as well as Si seeded with ZnO nanocrystals. Time-resolved SEM revealed growth kinetics of the ZnO nanostructures on Si, capturing the emergence of “infant” urchins at the early growth stage and subsequent progressive increase in the urchin nanoneedle length and density, whilst the spiky nanoneedle morphology was retained throughout the growth. ε-Zn(OH)2 orthorhombic crystals were also observed alongside the urchins. The crystal structures of the nanostructures at different growth time were confirmed by synchrotron X-ray diffraction measurements. On seeded Si substrates, a two-stage growth mechanism was identified, with a primary growth step of vertically aligned ZnO nanoneedle arrays preceding the secondary growth of the urchins atop the nanoneedle array. The antibacterial, anti-reflective, and wetting functionality of the ZnO urchins—with spiky nanoneedles and at high surface density—on Si substrates was demonstrated. First, bacteria colonisation was found to be suppressed on the surface after 24 h incubation in Gram-negative E. coli culture, in contrast to control substrates (bare Si and Si sputtered with 20 nm ZnO thin film). Secondly, the ZnO urchin surface, exhibiting superhydrophilic property with a water contact angle ~0°, could be rendered superhydrophobic with a simple silanization step, characterised by a water static contact angle θ of 159° ± 1.4° and contact angle hysteresis ∆θ < 7°. The dynamic superhydrophobicity of the surface was demonstrated by bouncing-off of a falling 10 μL water droplet, with a contact time of 15.3 milliseconds (ms), captured using a high-speed camera. Thirdly, it was shown that the presence of dense spiky ZnO nanoneedles and urchins on the seeded Si substrate exhibited a reflectance R < 1% over the wavelength range λ = 200–800 nm. The ZnO urchins with unique morphology via a facile fabrication route at room temperature, readily implementable on different substrates, may be further exploited for multifunctional surfaces and product formulations.

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Impact of Bioinspired Nanotopography on the Antibacterial and Antibiofilm Efficacy of Chitosan

Cited by 41 publications

References 53 publications

Adhesion and bactericidal properties of nanostructured surfaces dependent on bacterial motility

Adhesion and bactericidal properties of nanostructured surfaces dependent on bacterial motility

Facile Fabrication of Multifunctional ZnO Urchins on Surfaces

Facile Fabrication of Multifunctional ZnO Urchins on Surfaces

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