Validation of the mechano-bactericidal mechanism of nanostructured surfaces with finite element simulation

Cui, Qianqian; Liu, Tianqing; Li, Xiangqin; Zhao, Lidan; Wu, Qiqi; Wang, Xin; Song, Kedong

doi:10.1016/j.colsurfb.2021.111929

Cited by 27 publications

(51 citation statements)

References 55 publications

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“…Recent models suggest that this occurs at the point of contact between the nanostructure tip and cell membrane. 79,80 Beyond this primary mechanical interaction, the presence of ROS has been detected in bacteria cultured on nanostructured titanium. 31 Parallel to this observation, antioxidant and DNA-repair proteins were detected with high abundance, implicating oxidative stress as a contributing factor to bacterial cell death.…”

Section: Mechanical Disruption Of Anaerobic Dental Pathogens Incubate...mentioning

confidence: 99%

Spiked Titanium Nanostructures That Inhibit Anaerobic Dental Pathogens

Hayles

Hasan

Bright

et al. 2022

ACS Appl. Nano Mater.

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Peri-implantitis is a devastating oral disease that has given rise to a demand for improved implantable dental biomaterials that can integrate well into the supporting bone as well as resist bacterial colonization. Recent research has demonstrated that nanostructured titanium may be well positioned to meet this demand. An abundance of literature has established the in vitro efficacy of nanostructured titanium against bacteria cultured aerobically, but its efficacy against anaerobic bacteria relevant to dental infections remains unknown. In the present study, we engineered sharp, spikelike nanostructures on commercially pure titanium surfaces using hydrothermal etching and challenged them with three clinically relevant, anaerobic dental pathogens: Streptococcus mutans, Fusobacterium nucleatum, and Porphyromonas gingivalis. Our results demonstrated that titanium nanostructures bearing sharp protrusions can be effective at eliminating bacteria in anaerobic conditions, in both single-species (up to ∼94% cell death) and dual-species (up to ∼70% cell death) models. Furthermore, surface modification greatly enhanced the efficacy of azithromycin treatment against anaerobic dental pathogens, compared to a control titanium surface. At 2× MIC (minimum inhibitory concentration), azithromycin eliminated 99.4 ± 0.3% of S. mutans on the nanostructured surface within 10 days, while only 26% of the bacteria were killed on the control surface. A similar result was observed for P. gingivalis. The data presented here serve as a promising foundation of knowledge on which to build a greater understanding of how nanostructured biomaterials can be effective in anaerobic environments such as that found in the oral cavity.

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Section: Mechanical Disruption Of Anaerobic Dental Pathogens Incubate...mentioning

confidence: 99%

Spiked Titanium Nanostructures That Inhibit Anaerobic Dental Pathogens

Hayles

Hasan

Bright

et al. 2022

ACS Appl. Nano Mater.

View full text Add to dashboard Cite

show abstract

“…Pillar deflection is most prominent at the edges of bacteria, where pillars seem to be bending toward the bacterium, as shown in Figure and observed in other publications. , The biophysical model assumes a vertical attractive force toward the surface resulting from van der Waals forces and electrostatic interactions. Further efforts to shed light on the mechanism of the dynamic nature of bacterial death on nanostructured surfaces using finite element simulations also relied on vertical attractive forces. , Their results show no pillar bending toward the bacterium. In fact, the bases of these pillars bending toward the bacterium are outside the projected area of the bacterium.…”

Section: Resultsmentioning

confidence: 99%

“…Further efforts to shed light on the mechanism of the dynamic nature of bacterial death on nanostructured surfaces using finite element simulations also relied on vertical attractive forces. 58,59 Their results show no pillar bending toward the bacterium. In fact, the bases of these pillars bending toward the bacterium are outside the projected area of the bacterium.…”

Section: Acs Appliedmentioning

confidence: 95%

Effect of Flexibility and Size of Nanofabricated Topographies on the Mechanobactericidal Efficacy of Polymeric Surfaces

Lohmann

Tripathy

Milionis

et al. 2022

ACS Appl. Bio Mater.

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Driven by the growing threat of antimicrobial resistance, the design of intrinsically bactericidal surfaces has been gaining significant attention. Proposed surface topography designs are often inspired by naturally occurring nanopatterns on insect wings that mechanically damage bacteria via membrane deformation. The stability of and the absence of chemicals in such surfaces support their facile and sustainable employment in avoiding surface-born pathogen transmission. Recently, the deflection of controllably nanofabricated pillar arrays has been shown to strongly affect bactericidal activity, with the limits of mechanical effectiveness of such structures remaining largely unexplored. Here, we examine the limits of softer, commonly used polymeric materials and investigate the interplay between pillar nanostructure sizing and flexibility for effective antibacterial functionality. A facile, scalable, UV nanoimprint lithography method was used to fabricate nanopillar array topographies of variable sizes and flexibilities. It was found that bacterial death on nanopillars in the range of diameters ≤100 nm and Young’s moduli ≥1.3 GPa is increased by 3.5- to 5.6-fold, while thicker or softer pillars did not reduce bacterial viability. To further support our findings, we performed a finite element analysis of pillar deformation. It revealed that differences in the amount of stress exerted on bacterial membranes, generated from the stored elastic energy in flexible pillars, contribute to the observed bactericidal performance.

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“…55 The turgor pressure of the cell is 0.3 atm, and this was used to model the inner boundary pressure load. 56 For finite element modelling in COMSOL Multiphysics 5.6, the Structural Mechanics module was used in Stationary study mode with an auxiliary sweep of the particle surface displacement. Contact boundary conditions between the upper surface of the shell and the particle were specified, and prescribed vertical displacement towards the bacterium was defined for the particle surface (Table 1).…”

Section: Methodsmentioning

confidence: 99%

“…S2A, ESI †). Previously obtained physical properties of bacteria 41,42 were used for numerical simulations, e.g., Young's modulus (30 MPa and 95 MPa for Escherichia coli and Staphylococcus aureus, respectively), Poisson's ratio (0.2 for both strains), cell-wall thickness (7 nm and 40 nm for E. coli and S. aureus, respectively), and bacteria turgor pressure (B0.03 MPa for both strains) values, as the boundary conditions for the inner cell wall surface. The main mechanical properties of these types of cell walls are quite similar to oral bacteria examples due to the similar compositions of cell walls in cases with Gram-positive and Gram-negative structures.…”

Section: Quantitative Modelling For Shape Predictionmentioning

confidence: 99%