Natural bactericidal surfaces are found on the wings of cicada and dragonfly that compose of nanopatterns such as nanopillar arrays. It has been observed that the nanopillars can penetrate into the bacterial walls or stretch them, which results in the death of bacteria cells. It was reported that, in the case of orthopaedic implants, implant-associated infections (IAIs) are on the major factors limiting the longevity of implants. The nanopatterned surface offers an attractive “chemical-free” and wide-spectrum strategy to fight against bacteria-related infections and fouling. Efforts have been made to fabricate surfaces decorated with similar types of nanopatterns by researches, which are demonstrated to exhibit bactericidal behavior. Although the bio-inspired nanostructured surface has the great potential to mitigate the risk of infection for implants through wide-spectrum antimicrobial capability. However, the fundamental bactericidal mechanisms of nanopatterned surface is not clear, which prevent the rational design and wide application of such kind bio-inspired surface. One critical research question needs to be answered to realize its full potential: how the bacteria cell response to the nanopatterns, which determines the bactericidal performance of the nanostructured surface. Considering the length and temporal scales of the bactericidal phenomena, it is extremely challenging to observe the cell-nanostructure interaction directly through experimental study. In this work, we will develop mechanical single cell model of bacteria based on finite element analysis to simulate the interactions between different strains of bacteria and the nanostructured surface. The nanostructured surface contains nanopillar arrays, which are made of polymer materials. For the bacteria models, the cell mass density and shapes are directly determined from experimental data in the literature. The cell wall is considered as elastic while the cytoplasm is considered as nonlinear viscoelastic, which is suggested by atomic force microscopy measurements. Different strains of bacteria are simulated by adopting the corresponding geometry and material properties from experimental values. The mechanical response of the bacteria cell on the nanopillar arrays will be studied based on estimated stress and strain distributions within the cell. The bactericidal efficiency of the nanopillars will be determined by the induced maximum stress and strain in the cell. A systematic study will be conducted to investigate the effects of heights, width and spacing of nanopillars on the mechanical deformation of bacteria cells. In addition, the bactericidal efficiency of nanopillars for gram-negative and gram-positive bacteria will be investigated, respectively. We expect to establish quantitative structure-performance relationship of the nanostructured surface in terms of the bactericidal efficiency, which can help the design of such bio-inspired antibacterial surface for a wide range of applications. 


Numerical Study on Antibacterial Effects of Bio-Inspired Nanostructured Surface

Division / Sponsors: 
Aerospace, Bioengineering, Applied Mechanics, Design Engineering Division, Advanced Energy Systems, Manufacturing Engineering Division, Noise Control and Acoustics, Nondestructive Evaluation, Diagnosis, and Prognosis (NDPD), Nuclear Engineering Division, Process Industries Division, Fluids Engineering, Heat Transfer, Materials, Microelectromechanical Systems, Safety Engineering and Risk Analysis, Computers & Information in Engineering


Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2020/volume/84478

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