Enhanced antimicrobial activity of Cu-decorated graphene nanoplatelets and carbon nanotubes

Author(s)

Assis, Marcelo ; Santos, Jeziel R. ; Cipriano, Matheus H. L. ; Reis, Roberta Y. N. ; Ribeiro, Lara K. ; Mascaro, Lucia H. ; Longo, Elson ; Andres, Juan

• Document type: Journal article
• Source: SURFACES AND INTERFACES; v. 53, p. 12-pg., 2024-09-12.

Abstract

New materials with antimicrobial properties are necessary to combat the proliferation and transmission of pathogenic microorganisms. In this work, graphene nanoplatelets (GPN) and multi-walled carbon nanotubes (CNT) decorated with Cu nanoparticles (Cu NPs) were synthetized by microwave-assisted hydrothermal method, varying the Cu content from 1 to 10 wt.%. These materials were characterized by X-ray diffraction (XRD), Raman spectroscopy, and scanning and transmission electron microscopy (SEM and TEM) and their antimicrobial activity against Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) were evaluated. The sample with 10 wt.% Cu at CNTs is more effective compared to GPNs. Then, brass coatings with pure and Cu-decorated (10 wt.%) CNTs and GPNs were prepared by spin coating to evaluate the antimicrobial activity of these surfaces. It was observed that coatings with the carbon matrices reduced microbial growth by 2 logs, whereas decoration with Cu NPs amplified this value, especially for the Cu/CNT coating, achieving up to a 6-log reduction after 24 h of contact. The stability of the antimicrobial activity of these coatings was evaluated over 5 successive 24-h cycles, demonstrating high stability. DFT calculations on a simplified model, based on a Cu atom adsorbed on GPN and CNT, reveal a thermodynamically favorable pathway to explain the antibacterial activity. The results show a mechanism that could promote the formation of the precursors of hydroxyl (center dot OH), superoxide (center dot O-2(-)), and hydroperoxyl (center dot OOH) radicals, which are adsorbed strongly on GPN and CNT surfaces. This study highlighted the critical role of Cu NPs-loaded on carbon materials, GPN and CNT, in enhancing the antibacterial activity. (AU)

• FAPESP's process: 23/12399-7 - Influence of rare-earth doping on the BiVO4 photoanode structure for biomass degradation and fuel cells
• Grantee: Lara Kelly Ribeiro da Silva
• Support Opportunities: Scholarships in Brazil - Support Program for Fixating Young Doctors
• FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
• Grantee: Elson Longo da Silva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 23/01415-1 - Influence of rare-earth doping on the BiVO4 photoanode structure for biomass degradation and fuel cells
• Grantee: Lucia Helena Mascaro Sales
• Support Opportunities: Regular Research Grants
• FAPESP's process: 21/11326-0 - Study of copper and copper oxide photoelectrodes for wastewater treatment after the COVID-19 pandemic
• Grantee: Roberta Yonara Nascimento Reis
• Support Opportunities: Scholarships in Brazil - Doctorate