Rapid synthesis of MXenes and their potential risk to bacterial communities in the tomato rhizosphere

Abstract

MXenes are a group of two-dimensional (2D) nanomaterials of significant interest and have tremendous application and development prospects because of their excellent physical and chemical properties. Rhizosphere bacteria colonize the narrow ecosystem region surrounding plant roots and are critical in supporting the growth and ecological fitness of the host plant while exhibiting sensitivity to variations in the soil environment. However, through complex and unrecognized interactions, MXenes may have unexpected effects on the rhizosphere bacterial community. Therefore, their potential risks must be assessed before they are widely used and eventually exposed to the soil environment. In this study, we optimized the efficient one-step mechanical exfoliation (ECO-ME) method, enabling the successful preparation of MXene multiple times within one day. Subsequently, the influence of the prepared E-Ti₃C₂ on rhizosphere bacterial communities of tomato plants was assessed using high-throughput sequencing. Surprisingly, no significant variations in the rhizosphere bacterial communities were observed even when 10 mL of 1200 μg mL⁻¹ E-Ti₃C₂ dispersion was directly applied through a root irrigation strategy. Furthermore, slight fluctuations in the bacterial community that were triggered reverted to the initial state after 6 days, confirming the negligible effect of introducing E-Ti₃C₂ into the soil environment. This study offers a rapid and economical method for MXene preparation and provides a prospective investigation of the soil environmental risk for practical MXene applications.