Deciphering the Roles of Interspace and Controlled Disorder in the Bactericidal Properties of Nanopatterns against <i>Staphylococcus aureus</i>
Khashayar Modaresifar,
Lorenzo B. Kunkels,
Mahya Ganjian,
Nazli Tümer,
Cornelis W. Hagen,
Linda G. Otten,
Peter-Leon Hagedoorn,
Livia Angeloni,
Murali K. Ghatkesar,
Lidy E. Fratila-Apachitei,
Amir A. Zadpoor
Affiliations
Khashayar Modaresifar
Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, 2628CD Delft, The Netherlands
Lorenzo B. Kunkels
Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, 2628CD Delft, The Netherlands
Mahya Ganjian
Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, 2628CD Delft, The Netherlands
Nazli Tümer
Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, 2628CD Delft, The Netherlands
Cornelis W. Hagen
Department of Imaging Physics, Faculty of Applied Sciences, Delft University of Technology, 2628CJ Delft, The Netherlands
Linda G. Otten
Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, 2626HZ Delft, The Netherlands
Peter-Leon Hagedoorn
Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, 2626HZ Delft, The Netherlands
Livia Angeloni
Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, 2628CD Delft, The Netherlands
Murali K. Ghatkesar
Department of Precision and Microsystems Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, 2628CD Delft, The Netherlands
Lidy E. Fratila-Apachitei
Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, 2628CD Delft, The Netherlands
Amir A. Zadpoor
Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, 2628CD Delft, The Netherlands
Recent progress in nano-/micro-fabrication techniques has paved the way for the emergence of synthetic bactericidal patterned surfaces that are capable of killing the bacteria via mechanical mechanisms. Different design parameters are known to affect the bactericidal activity of nanopatterns. Evaluating the effects of each parameter, isolated from the others, requires systematic studies. Here, we systematically assessed the effects of the interspacing and disordered arrangement of nanopillars on the bactericidal properties of nanopatterned surfaces. Electron beam induced deposition (EBID) was used to additively manufacture nanopatterns with precisely controlled dimensions (i.e., a height of 190 nm, a diameter of 80 nm, and interspaces of 100, 170, 300, and 500 nm) as well as disordered versions of them. The killing efficiency of the nanopatterns against Gram-positive Staphylococcus aureus bacteria increased by decreasing the interspace, achieving the highest efficiency of 62 ± 23% on the nanopatterns with 100 nm interspacing. By comparison, the disordered nanopatterns did not influence the killing efficiency significantly, as compared to their ordered correspondents. Direct penetration of nanopatterns into the bacterial cell wall was identified as the killing mechanism according to cross-sectional views, which is consistent with previous studies. The findings indicate that future studies aimed at optimizing the design of nanopatterns should focus on the interspacing as an important parameter affecting the bactericidal properties. In combination with controlled disorder, nanopatterns with contrary effects on bacterial and mammalian cells may be developed.
