Surface Engineering of Carbon Nano-Onions for Folic Acid-Mediated Targeted Chemotherapeutic Delivery

Carbon nano-onions (CNOs) are an emerging class of carbon nanomaterials with distinctive physicochemical properties, including small size, high surface area, and favorable biocompatibility. Their multilayered carbon structure and accessible surface chemistry make them attractive candidates for functional nanomaterials in biomedical applications. In this work, we report the synthesis and functionalization of CNOs with folic acid (FA) to achieve receptor-mediated targeting of cancer cells overexpressing folate receptors. The FA-modified CNOs were further engineered for the efficient loading and controlled release of doxorubicin (DOX). Surface modifications were confirmed by a comprehensive suite of spectroscopic, microscopic, and thermal characterization techniques, which verified successful FA conjugation and drug incorporation. In vitro assays demonstrated that FA-functionalized CNOs significantly enhance cellular uptake and drug delivery efficiency compared to nontargeted controls. These results not only validate FA-CNOs as potential nanocarriers for cancer therapy but also underscore the versatility of CNOs as a tunable carbon nanomaterial platform for targeted delivery applications.