Diagnostic and therapeutic potential of carbon nanodots for ocular disease

Conventional therapeutics (eye drops, injectables, ointments, gels) for ocular diseases face several challenges, including low ocular permeability, rapid clearance, low bioavailability, and off-target effects due to complex anatomical barriers and physiological ocular events. Nanomedicine can avoid some challenges of conventional delivery systems by offering prolonged ocular retention, site-specific targeted drug delivery, low toxicity, improved bioavailability, and therapeutic activity. Further, theranostic nanomedicines offer the advantages of diagnostic and therapeutic features during treatment. Carbon dots (CDs), also known as carbon nanodots (CNDs) or carbon quantum dots (CQDs), are ultra-low-sized, zero-dimensional nanomaterials with a diameter below 10 nm, and have received attention due to their excellent fluorescence, tunable emission, biocompatibility, aqueous solubility, surface functionalization ability, stability, safety, and cost-effectiveness. A growing number of studies explore the therapeutic, diagnostic, or theranostic use of CDs for ocular applications, demonstrating real-time monitoring of disease progression and treatment efficacy in ocular disease models. CDs have been explored for ocular drug delivery, fluorescent angiography, ocular bioimaging, and treatment in models of various ocular diseases, including bacterial keratitis, glaucoma, vitreous opacification, and neovascular age-related macular degeneration (nAMD). In this special report, the potential of CDs for ophthalmic applications is reviewed based on publications over the last decade.