Evaluation of garlic derived carbon dots for citocompatibility and radical scavenging: from structure to properties

Carbon dots are an emerging and fascinating carbon-based material, characterized by nearly spherical shapes with size lower than 10 nm, characterized by excellent optical properties and intense fluorescence. Carbon dots are suitable for various applications, like in optoelectronics, photocatalysis, sensing, and, particularly in the biomedical field. Thanks to their biocompatibility and low toxicity, they can be employed as drug and gene carriers, perform antioxidant actions, and are useful in theranostic applications. Their fluorescence capability allows them to act as chemical probes for detecting specific metallic ions and for bioimaging. Another outstanding feature is the tunability of their properties. Tuning of the carbon dots properties can be achieved by tailoring their composition, chemical structure, and size within the range 10-80 nm. Carbon dots are organic nanoparticles and can be produced through various synthesis methodologies. In this thesis work, carbon dots were synthesized using biomass, specifically garlic, through a hydrothermal synthesis. This approach, classified as a bottom-up technique, involves a straightforward realization but incorporates a top-down approach by including the cutting of the starting biomass. Five different syntheses were conducted varying the time and temperature conditions to select the process parameters that led to the best compromise between yield, fluorescence emission, and degree of carbonization. The goal was to combine the anti-inflammatory properties of garlic with the optical characteristics of nanoparticles to create carbon dots capable of acting as radical scavengers. Cellular viability studies were conducted using the proliferation assay (MTT assay) to assess the metabolic activity of A549-GFP cells exposed to carbon dots. The produced nanoparticles were characterized for fluorescence using a fluorimeter and UV-Vis Spectrophotometry. Their chemical composition was analyzed through Thermogravimetric analysis (TGA) and Fourier-transform Infrared Spectroscopy (FT-IR). Regarding nanoparticles size, measurements were performed using Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM).