Evaluation of the antibacterial power and biocompatibility of zinc oxide nanorods decorated graphene nanoplatelets: new perspectives for antibiodeteriorative approaches

Zanni, Elena; Bruni, Erika; Chandraiahgari, Chandrakanth Reddy; Bellis, Giovanni De; Santangelo, M.; Leone, Maurizio; Bregnocchi, Agnese; Mancini, Patrizia; Sarto, Maria Sabrina; Uccelletti, Daniela

doi:10.1186/s12951-017-0291-4

Cited by 36 publications

(25 citation statements)

References 50 publications

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“…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]. The sharp topography of the nanoneedles is particularly effective in disrupting the bacterial cell wall by imparting localized stress on the bacterial membrane [80].…”

Section: Resultsmentioning

confidence: 91%

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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Section: Resultsmentioning

confidence: 91%

Facile Fabrication of Multifunctional ZnO Urchins on Surfaces

Tripathy

Wąsik

Sreedharan

et al. 2018

Colloids and Interfaces

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show abstract

“…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 inhibits the bacteria to colonise on the surface of the ZnO urchins 18,[72][73][74] . The sharp topography of the nanoneedles are particularly effective in disrupting the bacterial cell wall by imparting the localised stress on the bacterial membrane 75 .…”

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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“…The antibacterial activity of the specimens was assessed against Gram-positive Staphylococcus aureus ATCC 25923, as previously described by Zanni et al [40]. The biofilm growth in 12-well microtiter plates was estimated by using the crystal violet (CV) assay, a dye specific to biofilm biomass.…”

Section: Antibacterial Assaymentioning

confidence: 99%

Antibacterial Activity against Staphylococcus Aureus of Titanium Surfaces Coated with Graphene Nanoplatelets to Prevent Peri-Implant Diseases. An In-Vitro Pilot Study

Pranno

Monaca

Polimeni

et al. 2020

IJERPH

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Dental implants are one of the most commonly used ways to replace missing teeth. Nevertheless, the close contact with hard and soft oral tissues expose these devices to infectious peri-implant diseases. To prevent such infection, several surface treatments have been developed in the last few years to improve the antimicrobial properties of titanium dental implants. In this in-vitro pilot study, the antimicrobial activity of titanium surfaces coated with different types of graphene nanoplatelets are investigated. Six different colloidal suspensions of graphene nanoplatelets (GNPs) were produced from graphite intercalated compounds, setting the temperature and duration of the thermal shock and varying the number of the exfoliation cycles. Titanium disks with sand-blasted and acid-etched surfaces were sprayed with 2 mL of colloidal GNPs suspensions. The size of the GNPs and the percentage of titanium disk surfaces coated by GNPs were evaluated through a field emission-scanning electron microscope. The antibacterial activity of the specimens against Staphylococcus aureus was estimated using a crystal violet assay. The dimension of GNPs decreased progressively after each sonication cycle. The two best mean percentages of titanium disk surfaces coated by GNPs were GNPs 1050 • /2 and GNPs 1150 • /2 . The reduction of biofilm development was 14.4% in GNPs 1150 • /2 , 20.1% in GNPs 1150 • /3 , 30.3% in GNPs 1050 • /3 , and 39.2% in GNPs 1050 • /2 . The results of the study suggested that the surface treatment of titanium disks with GNPs represents a promising solution to improve the antibacterial activity of titanium implants.

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Evaluation of the antibacterial power and biocompatibility of zinc oxide nanorods decorated graphene nanoplatelets: new perspectives for antibiodeteriorative approaches

Cited by 36 publications

References 50 publications

Facile Fabrication of Multifunctional ZnO Urchins on Surfaces

Facile Fabrication of Multifunctional ZnO Urchins on Surfaces

Facile Fabrication of Multifunctional ZnO Urchins on Surfaces

Antibacterial Activity against Staphylococcus Aureus of Titanium Surfaces Coated with Graphene Nanoplatelets to Prevent Peri-Implant Diseases. An In-Vitro Pilot Study

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