Antibiofilm Effect of Nitric Acid-Functionalized Carbon Nanotube-Based Surfaces against <i>E. coli</i> and <i>S. aureus</i>

Chemically modified carbon nanotubes are recognized as effective materials for tackling bacterial infections. In this study, pristine multi-walled carbon nanotubes (p-MWCNTs) were functionalized with nitric acid (f-MWCNTs), followed by thermal treatment at 600 °C, and incorporated into a poly(dimeth...

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Main Authors: Marisa Gomes (Author), Rita Teixeira-Santos (Author), Luciana C. Gomes (Author), Francisca Sousa-Cardoso (Author), Fábio M. Carvalho (Author), Andreia R. Tomé (Author), Olívia S. G. P. Soares (Author), Kathryn A. Whitehead (Author), Filipe J. Mergulhão (Author)
Format: Book
Published: MDPI AG, 2023-11-01T00:00:00Z.
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Summary:Chemically modified carbon nanotubes are recognized as effective materials for tackling bacterial infections. In this study, pristine multi-walled carbon nanotubes (p-MWCNTs) were functionalized with nitric acid (f-MWCNTs), followed by thermal treatment at 600 °C, and incorporated into a poly(dimethylsiloxane) (PDMS) matrix. The materials' textural properties were evaluated, and the roughness and morphology of MWCNT/PDMS composites were assessed using optical profilometry and scanning electron microscopy, respectively. The antibiofilm activity of MWCNT/PDMS surfaces was determined by quantifying culturable <i>Escherichia coli</i> and <i>Staphylococcus aureus</i> after 24 h of biofilm formation. Additionally, the antibacterial mechanisms of MWCNT materials were identified by flow cytometry, and the cytotoxicity of MWCNT/PDMS composites was tested against human kidney (HK-2) cells. The results revealed that the antimicrobial activity of MWCNTs incorporated into a PDMS matrix can be efficiently tailored through nitric acid functionalization, and it can be increased by up to 49% in the absence of surface carboxylic groups in f-MWCNT samples heated at 600 °C and the presence of redox activity of carbonyl groups. MWCNT materials changed the membrane permeability of both Gram-negative and Gram-positive bacteria, while they only induced the production of ROS in Gram-positive bacteria. Furthermore, the synthesized composites did not impact HK-2 cell viability, confirming the biocompatibility of MWCNT composites.
Item Description:10.3390/antibiotics12111620
2079-6382