No abstract

High-security nanoplatform with enhanced therapy compliance is extremely promising for tumor. Herein, using a simple and high-efficient self-assembly method, a novel active-targeting nanocluster probe, namely, Ag 2 S/chlorin e6 (Ce6)/DOX@DSPE-mPEG 2000 -folate (ACD-FA) is synthesized. Experiments indicate that ACD-FA is capable of specifically labeling tumor and guiding targeting ablation of the tumor via precise positioning from fluorescence and photoacoustic imaging. Importantly, the probe is endowed with a photodynamic "on-off " effect, that is, Ag 2 S could effectively quench the fluorescence of chlorin e6 (89.5%) and inhibit release of 1 O 2 (92.7%), which is conducive to avoid unwanted phototoxicity during transhipment in the body, and only after nanocluster endocytosed by tumor cells could release Ce6 to produce 1 O 2 . Moreover, ACD-FA also achieves excellent acid-responsive drug release, and exhibits eminent chemo-photothermal and photodynamic effects upon laser irradiation. Compared with single or two treatment combining modalities, ACD-FA could provide the best cancer therapeutic effect with a relatively low dose, because it made the most of combined effect from chemo-photothermal and controlled photodynamic therapy, and significantly improves the drug compliance. Besides, the active-targeting nanocluster notably reduces nonspecific toxicity of both doxorubicin and chlorin e6. Together, this study demonstrates the potency of a newly designed nanocluster for nonradioactive concomitant therapy with precise tumortargeting capability.

A graphene quantum dot (GQD) is a novel carbon nanomaterial with the advantages of low cost and no pollution. It has attracted serious attention in the biomedical fields because of its stabilities and tunable fluorescence wavelength. In this manuscript, an N-doped graphene quantum dot (N-GQD) was synthesized by a hydrothermal method using citric acid as the carbon source and urea as the nitrogen source. X-ray diffraction, Raman spectroscopy, transmission electron microscopy, UV-vis absorption spectrum, and fluorescence spectrum were used to characterize the N-GQD. The results showed that the N-GQD had a uniform size of about 5 nm. The two fluorescence emission peaks, one in the visible light region showed a 49.75% quantum yield, while another in the near infrared region was 2.49%. The photothermal conversion efficiency was 62.53%, higher than any kind of carbon nanomaterial in existence today. MTT and a long-term cytotoxicity experiment confirmed that the N-GQD had low cytotoxicity. The probe also had the ability of photoacoustic response at the same time. After coupling with folic acid, it presented imaging and photothermal therapy on the cells, which has great application prospects in the early diagnosis and treatment of tumors.