Plasma-Etched Vertically Aligned CNTs with Enhanced Antibacterial Power

Abstract

The emergence of multidrug-resistant bacteria represents a growing threat to public health, and it calls for the development of alternative antibacterial approaches not based on antibiotics. Here, we propose vertically aligned carbon nanotubes (VA-CNTs), with a properly designed nanomorphology, as effective platforms to kill bacteria. We show, via a combination of microscopic and spectroscopic techniques, the ability to tailor the topography of VA-CNTs, in a controlled and time-efficient manner, by means of plasma etching processes. Three different varieties of VA-CNTs were investigated, in terms of antibacterial and antibiofilm activity, against Pseudomonas aeruginosa and Staphylococcus aureus: one as-grown variety and two varieties receiving different etching treatments. The highest reduction in cell viability (100% and 97% for P. aeruginosa and S. aureus, respectively) was observed for the VA-CNTs modified using Ar and O2 as an etching gas, thus identifying the best configuration for a VA-CNT-based surface to inactivate both planktonic and biofilm infections. Additionally, we demonstrate that the powerful antibacterial activity of VA-CNTs is determined by a synergistic effect of both mechanical injuries and ROS production. The possibility of achieving a bacterial inactivation close to 100%, by modulating the physico-chemical features of VA-CNTs, opens up new opportunities for the design of self-cleaning surfaces, preventing the formation of microbial colonies.

Spectromicroscopy Study of Induced Defects in Ion-Bombarded Highly Aligned Carbon Nanotubes

“…At this high resolution spatial scale, a waviness in the orientation is visible that does not affect the average vertical alignment. On the top, a crust of twisted nanotubes of the order of few 10 nm is present, in agreement with previous observations on VA-CNTs [ 29 ]. All MWCNTs samples used in this experiment present heights of about 200 m and diameters of about 10 nm, more details in the SI (Figure S1) .…”

“…Vertically aligned MWCNTs were grown by the chemical vapor deposition (CVD) method with a home-made thermal CVD reactor in UHV, at the TITAN laboratory in Sapienza University of Rome, as described elsewhere [ 29 , 30 ]. Silicon was used as growth substrate, with a 2 m thick buffer layer of SiO .…”

Screening of low‐toxic zinc oxide nanomaterials and study the apoptosis mechanism of NSC‐34 cells

“…These disturbances are caused by alterations in the structure, permeability, and transport activity of the membrane. [19,[21][22][23] 3D Nanoflowers are a recently developed type of nanomaterials that show great potential in the rapid and accurate detection of diseases like Parkinson's disease and Alzheimer's disease.…”

“…Additionally, nanorods and nanosheets contribute to cell death mediated by oxidative stress, involving both ROS-dependent and ROS-independent mechanisms. [13][14][15][16][17][18][19][20][21][22][23] The cytotoxicity of ZnO-NMts has been demonstrated in both in vitro and in vivo studies using various mammalian cells. Different levels of toxicity have been observed on human A549 cells, human gingiva cells, zebrafish cells, HepG2 cells, and human endothelial cells.…”

“…Additionally, nanorods and nanosheets contribute to cell death mediated by oxidative stress, involving both ROS‐dependent and ROS‐independent mechanisms. [ 13–23 ]…”