Salivary acid-modified carbon dots loaded with paclitaxel for imaging-guided combination treatment of breast cancer

Due to the high morbidity and mortality, cancer has become a global health crisis, posing a great threat to human health. Traditional cancer treatments include surgery, chemotherapy and radiotherapy, but these methods can lead to serious adverse reactions. Therefore, it is of great significance to develop new and effective methods for cancer diagnosis and treatment. In this article, orange fluorescent carbon dots (CDs) were synthesized by the hydrothermal method using biogenic amines. Upon further surface modification with a salivary acid, a novel nanocomplex (CDs-SA-PTX) was prepared by loading the chemotherapeutic drug paclitaxel that could be released under a pH-responsive behavior. In addition, upon irradiation with a near-infrared laser, the temperature of the CDs-SA-PTX nanocomplexes increased to 45.7 °C, indicating a good photothermal effect with a conversion efficiency of 43.8%. In the cellular uptake experiment, CDs-SA-PTX exhibited good capability for nucleolar targeting similar to CDs. The cell viability experiment showed that CDs-SA-PTX together with laser irradiation demonstrated the best breast cancer cell killing ability than other groups. Further <i>in vivo</i> data indicated that CDs-SA-PTX could be efficiently enriched in tumor tissues and could almost completely inhibit tumor growth with laser irradiation. The nanocomplexes provide an ideally versatile platform with the advantages of simple ingredients, easy preparation, active targeting, imaging-guided photothermal therapy and chemotherapy.