Cooperative stiffening of flexible high aspect ratio nanostructures impart mechanobactericidal activity to soft substrates

Roy, A and Patil, D and Yarlagadda, PKDV and Chatterjee, K (2023) Cooperative stiffening of flexible high aspect ratio nanostructures impart mechanobactericidal activity to soft substrates. In: Journal of Colloid and Interface Science, 652 . pp. 2127-2138.

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Abstract

Understanding how bacteria interact with surfaces with micrometer and/or sub-micrometer roughness is critical for developing antibiofouling and bactericidal topographies. A primary research focus in this field has been replicating and emulating bioinspired nanostructures on various substrates to investigate their mechanobactericidal potential. Yet, reports on polymer substrates, especially with very high aspect ratios, have been rare, despite their widespread use in our daily lives. Specifically, the role of a decrease in stiffness with an increase in the aspect ratio of nanostructures may be consequential for the mechanobactericidal mechanism, which is biophysical in nature. Therefore, this work reports on generating bioinspired high aspect ratio nanostructures on poly(ethylene terephthalate) (PET) surfaces to study and elucidate their antibacterial and antibiofouling properties. Biomimetic nanotopographies with variable aspect ratios were generated via maskless dry etching of PET in oxygen plasma. It was found that both high and low-aspect ratio structures effectively neutralized Gram-negative bacterial contamination by imparting damage to their membranes but were unable to inactivate Gram-positive cells. Notably, the clustering of the soft, flexible tall nanopillars resulted in cooperative stiffening, as revealed by the nanomechanical behavior of the nanostructures and validated with the help of finite element simulations. Moreover, external capillary forces augmented the killing efficiency by enhancing the strain on the bacterial cell wall. Finally, experimental and computational investigation of the durability of the nanostructured surfaces showed that the structures were robust enough to withstand forces encountered in daily life. Our results demonstrate the potential of the single-step dry etching method for the fabrication of mechanobactericidal topographies and their potential in a wide variety of applications to minimize bacterial colonization of soft substrates like polymers. © 2023 Elsevier Inc.

Item Type:	Journal Article
Publication:	Journal of Colloid and Interface Science
Publisher:	Academic Press Inc.
Additional Information:	The copyright for this article belongs to the Academic Press Inc.
Keywords:	Bacteria; Biomimetics; Cell membranes; Ethylene; Micrometers; Nanostructured materials; Nanostructures; Substrates, Antibacterials; Antibiofouling; Aspect-ratio; Daily lives; High aspect ratio; High aspect ratio nano-structures; Research focus; Soft substrates; Submicrometers; Surface engineering, Aspect ratio, cell membrane protein; metal nanoparticle; nanomaterial; nanowire; oxygen; polyethylene terephthalate; polymer; reactive oxygen metabolite, antimicrobial activity; Article; bacterial cell wall; bacterial colonization; bactericidal activity; bacterium contamination; bacterium culture; biomimetics; capillary; chemical composition; chemical modification; confocal laser scanning microscopy; controlled study; cystic fibrosis; electron microscopy; finite element analysis; force; Gram negative bacterium; mechanobactericidal activity; nonhuman; plasma; Pseudomonas aeruginosa; rigidity; Staphylococcus aureus; structure analysis; surface property
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	30 Nov 2023 04:33
Last Modified:	30 Nov 2023 04:33
URI:	https://eprints.iisc.ac.in/id/eprint/83340

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