Abstract

Carbon dots are an emerging class of fluorescent nanoparticles within the carbon allotrope family. They have garnered significant interest in the field due to their cost-effective and sustainable synthesis, versatile optical and chemical properties, as well as low chemical toxicity. Typically, carbon dots possess a mean size of nearly 10 nm and are comprised primarily of sp2 carbons alongside oxygen, hydrogen and other heteroatoms. A variety of carbon sources ranging from simple molecules to more complex and heterogenous ones can be used to prepare these dots speaking to their sustainability and cost effectiveness. Their properties and surface chemistry are governed by the synthesis approach and starting precursors allowing us to endow them with various physico-optical properties including chirality, a property of interest due to its ubiquitous nature. Chirality has tremendous implications in drug development and design, as well as in applications such as catalysis, enantioselective recognition and sensing.
In this work, we explore the microwave-assisted synthesis of chiral carbon dots prepared from reactions of the achiral carbon-based molecule, citric acid, and the chiral amino acid, cysteine, in water. The effects of the synthesis parameters on inducing chirality in the dots were investigated in order to tailor the chiral and fluorescent properties of the dots. Separation techniques were used to glean additional insights into the formation mechanism of the dots. Finally, in order to better understand the importance of stereoselectivity in biological systems, we also utilized the chiral carbon dots as potential anti-microbials against various strains of bacteria. Our findings show promising results towards generating new insights and ideas in the field of antibiotics especially given the growing concern of global antibiotic resistance.