A dual-emission fluorescent nanocomposite of carbonized polymer dots-gold nanoclusters (CPDs/AuNCs) was successfully synthesized via electrostatic self-assembly with D-penicillamine as the stabilizer of the AuNCs. The as-prepared CPDs/AuNCs were systematically characterized in terms of morphology, crystal structure, and surface chemical composition by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and other techniques. The optical properties tests demonstrated that CPDs/AuNCs exhibited stable dual-emission fluorescence at 468 and 652 nm and possessed excellent environmental stability against pH and salt concentration changes as well as good storage and UV irradiation stability. In vitro cellular experiments on A549 cells verified that CPDs/AuNCs had low cytotoxicity, could rapidly penetrate the cell membrane, and achieve intracellular enrichment with a detectable red fluorescence signal at 5 min of incubation. Moreover, CPDs/AuNCs showed pH-responsive drug release behavior for doxorubicin (DOX) and norfloxacin (NFX) in vitro, and the drug-loaded complexes could be efficiently internalized by A549 cells to enhance the cytotoxicity of free drugs. This work completes the synthesis and systematic structural characterization of CPDs/AuNCs and verifies their multiple physicochemical and biological properties at the in vitro/cellular level, which provides a foundational experimental basis for the subsequent research on their application in biomedical imaging and tumor-targeted drug delivery.
Guo et al. (Thu,) studied this question.