Functionalization of carbon nano-onions for potential biomedical applications

Multi-shell fullerenes, known as carbon nano-onions (CNOs), are one of the allotrope forms of carbon that have received less research efforts compared to other carbon allotropes, e.g., carbon nanotubes, graphene, etc. In this work, we report the synthesis of "in-house made" CNOs, prepared by pulsed laser ablation technique, and we demonstrate the functionalization of CNOs with carboxylic groups followed by cisplatin adsorption, as a hybrid functionalization method. The results involve platinum-oxidizing nano-onions for further applications in the biomedical field, knowing that functionalization of CNOs with different functional groups improves their solubility and biocompatibility, resulting in an increased ability to penetrate the cells. The chemical composition, molecular structure, and morphological properties of the prepared samples were characterized by micro-Raman spectroscopy, Attenuated Total Reflection Infrared Transformed Fourier spectroscopy (FTIR), and High-Resolution Scanning Transmission Electron Microscopy (HR-STEM) equipped with the Energy-Dispersive X-ray spectroscopy module. The amount of Pt ion release from the cisplatin functionalized samples was studied using Inductively Coupled Plasma Mass Spectrometry (ICP-MS).