Fabrication of Metallic-Ion-Free Fullerenols as Peroxidase-Like Nanozymes to Stimulate Maize Early Growth

Abstract

Although fabrication of various fullerenols as agronanozymes has undergone remarkable expansion through employing various approaches, there is a lack of knowledge regarding the understanding of metallic-ion-free fullerenols. A feasible preparation technology to fabricate metallic-ion-free fullerenols was developed by heating-treatment oversaturated fullerene using H₂O₂ solution in o-dichlorobenzene. It was characterized as C₆₀(OH)₃₆·9H₂O by various measurements. Maize exposure of 50 mg/L C₆₀(OH)₃₆·9H₂O was investigated to significantly enhance growth traits, including seed germination and seedling growth. Additionally, through the integration of ESR spectrum, radical scavenging assay, and peroxidase-like catalytic performance in vitro, DAB staining to visualize the accumulated H₂O₂ content in vivo as well as investigating the activation of antioxidative performance, it offers insights into the combinational action mechanism of C₆₀(OH)₃₆·9H₂O on crop growth regulation. C₆₀(OH)₃₆·9H₂O directly scavenged accumulated H₂O₂ and indirectly activated the antioxidant system to suppress the H₂O₂ accumulation that acts like peroxidase activity. The present study gives an updated knowledge on synthesizing metallic-ion-free fullerenols with particular emphasis to their application as potential peroxidase-like nanozymes for regulatory roles in the improvement of crop growth.