Mineral-doped quantum fertilizers: boron-doped carbon dots promote sustainable agriculture and bacterial disease management

Abstract

Mineral (micro- and macronutrient)-doped quantum fertilizers developed via green synthesis represent a novel and transformative paradigm in sustainable agriculture, offering an ecofriendly strategy to maximize nutrient use efficiency, stimulate plant growth, and significantly reduce dependence on conventional chemical fertilizers. Here, we report the synthesis of Mg-, Zn-, Fe- and B-doped carbon quantum dots via a microwave-assisted method using oxalic acid as a molecular precursor. Notably, boron-doped carbon quantum dots (B-QDs) exhibit dual roles of plant growth promotion and significant antibacterial activity, as comprehensively characterized and functionally validated. Structural analyses (UV-vis spectroscopy, TEM, XPS, and fluorescence spectroscopy) confirmed the formation of quantum dots with an average diameter of 8–12 nm. B-QD treatments significantly enhanced seed germination, root elongation, and root number compared with the control (without mineral), boron alone, and Mg-doped and Fe-doped carbon quantum dots (Mg-QDs and Fe-QDs, respectively). However, Zn-doped carbon quantum dots (Zn-QDs) showed better seed germination and root elongation ability, but no antibacterial activity was observed. Fluorescence imaging further demonstrated efficient internalization and distribution of B-QDs in root tissues, while binding studies revealed strong interactions with pectic acid, a major polysaccharide in the cell walls suggesting a role in modulating cell wall dynamics. Antibacterial assays confirmed selective inhibition of phytopathogens such as Pseudomonas syringae and Ralstonia solanacearum without adversely affecting beneficial soil microbes. Furthermore, B-QDs displayed potent antibiofilm activity, validating their dual function as both plant growth promoters and eco-friendly antimicrobial agents. These seminal findings catalyze a new scientific quest to harness the power of “quantum fertilizers” toward advanced sustainable agriculture and next-generation plant disease management.