Synthesis of Carbon Dots from Banana Peel for Seed Health Diagnostics

Abstract

The increasing demand for sustainable nanomaterials has led to a surge in research focused on turning agricultural waste into value-added products. In this context, the current study aims to promote the germination and growth of Vigna mungo by using green synthesised carbon dots (CDs) nanoparticles. A simple, eco-friendly hydrothermal process was used to synthesize carbon dots from banana peel, which were then characterised using UV-vis spectroscopy, fluorescence spectroscopy, FTIR and TEM to confirm their optical properties, morphology and surface functionality. The produced CDs demonstrated outstanding fluorescent properties and were further evaluated for their efficacy in detecting seed-borne pathogens through fluorescence imaging and spectroscopic methods. Green synthesized CDs nanoparticles improve germination and growth of Vigna mungo compared to previously commercially produced CDs nanoparticles and other metal-oxide nanoparticles. Among different concentrations of synthesised CDs nanoparticles, a specific concentration (40%) effectively promotes the germination and growth of Vigna mungo, relative to the control system. Under cold stress (10°C) condition seeds treated with 40% CDs started germination earlier (day 5) than the control group (day 7). Under hot stress (50°C) conditions, no treatments promoted germination demonstrating that excessive heat prevented all growth. The paper piercing tests showed better seedling vigour in the 40% CDs-treated group through increased penetration ability. Additionally, CDs nanoparticles with a larger surface area promote plant development and increase fresh and dry biomass by adsorbing nutrients and facilitating nutrient translocation with improved water uptake inside plants.