Advances in carbon-based nanomaterials for stimuli-responsive and targeted drug delivery applications

Over the last few decades, carbon-based nanomaterials have attracted significant attention owing to their high surface area-to-volume ratio, tunable surface properties, greater physicochemical stability, and ease of multi-functionalization. This review comprehensively summarizes the role of carbon-based nanomaterials, including carbon dots, graphene and graphene oxide, carbon nanotubes, fullerenes, and nanodiamonds, for stimuli-responsive and targeted drug delivery applications with particular emphasis on anticancer therapeutics. Each nanocarrier system possesses distinct structural and functional characteristics that contribute to both higher drug loading and controlled drug release. The review emphasises quantitative drug-loading strategies, stimuli-responsive release behaviours, including loading/encapsulation efficiency, release kinetics and the level of biological validation. It also focuses on surface functionalization approaches that enhance targeting efficacy, cellular uptake, and therapeutic ability. Moreover, this review critically discusses the fundamental mechanisms governing drug transport and cellular uptake, as well as the physicochemical properties, influence of protein corona formation, pharmacokinetics, and biodistribution behaviour of these carbon-based nanomaterials, which are important parameters for targeted drug delivery and tumour-targeted anticancer therapy. Overall, this review emphasizes stimuli-responsive and targeted drug-delivery strategies, offering a comprehensive overview of the diverse biomedical applications of carbon-based nanomaterials across various administration routes to achieve effective therapeutic outcomes. Finally, it also addresses significant challenges and outlines future plans for developing safer, more effective carbon-based nanocarrier systems for targeted drug delivery.