Targeted NIR-triggered doxorubicin release using carbon dots–poly(ethylene glycol)–folate conjugates for breast cancer treatment

Carbon dot (CD)-based theranostics offers a promising approach for breast cancer (BC) treatment, integrating ultra-localized chemo-photothermal effects to address chemoresistance and enhance therapeutic control. Herein, the development of a targeted theranostic nanosystem for the chemo-phototherapy of breast cancer is described. Fluorescent and biocompatible CDs were passivated with 1,2-bis(3-aminopropylamino)ethane (bAPAE) and decorated with the targeting agent folic acid (FA) through conjugation with a PEG spacer. This yielded CDs-bAPAE-PEG-FA, hydrophilic nanocarriers (12 nm) with a high drug interaction surface. Fluorescence analysis confirmed their utility as bioimaging probes, while NIR light stimulation demonstrated good photothermal conversion. Doxorubicin-loaded CDs (CDs-bAPAE-PEG-FA/Dox) showed an on-demand NIR-boosted drug release, increased by 50% after localized NIR exposure, while in vitro studies on BC cells MCF-7 and MDA-MB-231 demonstrated NIR-enhanced antitumor efficacy, providing the opportunity to realize selective and remote-controlled synergistic therapy. Furthermore, uptake investigations highlighted the imaging potential of CDs and efficient internalization of doxorubicin, emphasizing FA's role in receptor-mediated specific targeting. Data suggest that CDs-bAPAE-PEG-FA/Dox could perform efficient image-guided and selective BC therapy, enhancing the therapeutic outcomes.