Surface-engineered graphitic carbon nitride nanoparticles for breast cancer therapy: advances in drug delivery and therapeutic response

Breast cancer remains a multifaceted and severe disease associated with high incidence and mortality, primarily due to delayed diagnosis, tumor heterogeneity, and the inadequate efficacy of conventional therapeutic approaches such as chemotherapy and radiotherapy, which are often aligned with poor selectivity, off-target toxicity, and drug resistance. These limitations underscore the need for the rational design of highly specific and efficient therapeutic strategies. In this context, nanotechnology-based drug delivery systems have emerged as promising alternatives, with graphitic carbon nitride (g-C₃N₄)-based nanomaterials gaining attention due to their tunable electronic properties, chemical stability, high surface area, and biocompatibility. The 2D nanostructure of g-C₃N₄ enables efficient drug entrapment coupled with stimuli-responsive release, while its intrinsic photocatalytic efficiency supports the generation of reactive oxygen species (ROS) under mild photoirradiation, augmenting cancer cell killing. Its responsiveness to the acidic tumor microenvironment facilitates localized drug release, improving therapeutic precision and reducing systemic side effects, while surface functionalization further enhances tumor targeting and cellular uptake. This review integrates recent developments in g-C₃N₄-based nanoplatforms for breast cancer therapy, focusing on material design, drug delivery performance, photodynamic mechanisms, and therapeutic outcomes, along with current challenges and future prospects for clinical translation.