Surface Modification of Carbon Nanotubes with an Enhanced Antifungal Activity for the Control of Plant Fungal Pathogen.

Xiuping Wang,Zilin Zhou,Fangfang Chen

doi:10.3390/ma10121375

Abstract

The addition of surface functional groups to multi-walled carbon nanotubes (MWCNTs) expands their application in engineering, materials, and life science. In the study, we explored the antifungal activities of MWCNTs with different surface groups against an important plant pathogenic fungi Fusarium graminearum. All of the OH-, COOH-, and NH2-modified MWCNTs showed enhanced inhibition in spore elongation and germination than the pristine MWCNTs. The length of spores decreased by almost a half from 54.5 μm to 28.3, 27.4, and 29.5 μm, after being treated with 500 μg·mL−1 MWCNTs-COOH, MWCNTs-OH, and MWCNTs-NH2 separately. Furthermore, the spore germination was remarkably inhibited by surface-modified MWCNTs, and the germination rate was only about 18.2%, three times lower than pristine MWCNTs. The possible antifungal mechanism of MWCNTs is also discussed. Given the superior antifungal activity of surface modified MWCNTs and the fact that MWCNTs can be mass-produced with facile surface modification at low cost, it is expected that this carbon nanomaterial may find important applications in plant protection.

Highlights

Carbon nanotubes (CNTs) are considered one of the most popular types of nanomaterials with unique morphologies and surface properties and have been intensively studied for various applications in bionanotechnology, including drug and gene delivery, tissue engineering, plant-technology [1,2], and other biomedical applications [3,4,5,6,7,8]
The spore length was affected by multi-wall carbon nanotubes (MWCNTs)—it was one-fifth shorter than the control group—and was significantly affected after it was treated with functional MWCNTs modified by the –OH group—It was almost three-fifths shorter than the control group on average, and one-half shorter than the group treated with pristine
This may be largely overcome by surface modification of the nanotube backbone, allowing the functional MWCNTs well dispersed in water to form a homogeneous solution. It is much more stable even after several days of storage [39]. These results suggest that the stability of the MWCNTs dispersions is critical to their antifungal activities

Summary

Introduction

Carbon nanotubes (CNTs) are considered one of the most popular types of nanomaterials with unique morphologies and surface properties and have been intensively studied for various applications in bionanotechnology, including drug and gene delivery, tissue engineering, plant-technology [1,2], and other biomedical applications [3,4,5,6,7,8]. A nanotube filter covered with a thin layer of single-walled carbon nanotubes (SWCNTs) are demonstrated to be effective in removing viral and bacterial pathogens [13,14,15]. From the toxicological point of view, single-walled carbon nanotubes have higher antimicrobial properties than multi-wall carbon nanotubes (MWCNTs) [18]. Our previous studies verified that CNTs displayed superior inactivation effects on the copper-resistant plant pathogenic microorganisms Ralstonia solanacearum, Fusarium graminearum, and F. oxysporum [19,20]. These findings implied that CNTs may be applied to phytopathogen control in plant protection because of their superior antimicrobial activity

Methods

Results

Discussion

Conclusion