Bactericidal efficacy of nanopatterned surface tuned by topography

Due to the exciting physical mechano-bactericidal approach developed in recent years using nanopatterned surfaces with its potential applications in biomedical engineering, now it becomes crucially important to fabricate optimal surface structures so as to achieve the best bactericidal ability. In this paper, the bactericidal efficacy of the cylindrical nanopillar-patterned surface and the sinusoidal nanopillar-patterned surface is presented via minimizing total free energy for a bacterial cell adhered on these two kinds of surfaces. Our theoretical analyses show that the adhesion depth at equilibrium along the nanopillar shafts and the corresponding stretching degree is related to the the nanopillar density and nanopillar radius. The bactericidal efficacy on the nanopillar-patterned surface is determined by the combination of nanopillar density and naopillar radius, which is also supported by the phase diagrams obtained, showing that at large internanopillar spacing and nanopillar radius, the sinusoidal nanopillar-patterned surface is more advantageous in bactericidal efficacy, while in small interspacing and nanopillar radius, the cylindrical nanopillar-patterned surface structure is more powerful. The conclusions obtained in this paper unveil how the mechano-bactericidal effect is achieved by tuning the topography of the nanopatterned surface, a technique helpful to the optimal design and fabrication of bio-mimicking nanotextured surfaces.