The inherent non-degradation and potential toxicity of pure carbon nanomaterials in vivo remain the main obstacles to clinical translation. This study attempts to prepare a novel biodegradable caramelized hollow mesoporous carbon nanospheres (CHMCNs) with mesoporous shells and a large cavity, which can be decomposed into small particles (~ 5 nm) within 7 days under physiological conditions. By varying the synthesis parameters and templates, CHMCNs with different morphologies can be obtained to meet different application requirements. Meanwhile, CHMCNs exhibit excellent biocompatibility and high drug-loading efficiency, enabling effective delivery of anticancer drugs (DOX) into cells. In addition, due to the good photothermal efficiency (PTT, 29.7%), CHMCNs facilitate pH/NIR dual-responsive drug release under NIR irradiation, resulting in an excellent synergistic chemo-photothermal therapy effect. The results indicate that CHMCNs is a promising drug delivery carrier. In conclusion, this work addresses the non-degradable defects of traditional mesoporous carbon nanomaterials (MCN) and proposes a novel nanocarrier system for tumor treatment.

Synthesis and antitumor efficacy of biodegradable hollow mesoporous carbon nanocarriers
    Abstract
    1 Introduction
    2 Experimental section
        2.1 Chemical reagents, cells, animals
        2.2 Synthesis of SiO2 spheres
        2.3 Synthesis of MSNs
        2.4 Preparation of CHMCNs
        2.5 Structural characterization
        2.6 Measurement of photothermal effect
        2.7 Cytotoxicity assay
        2.8 Degradation behavior of CHMCNs under simulated physiological conditions in vitro
        2.9 Cell uptake and biodegradation
        2.10 Drug loading and drug release analysis
        2.11 Cellular uptake of the CHMCNs-DOX
        2.12 Release behavior of NIR stimulation in cells
        2.13 Chemo-photothermal therapy in vitro
        2.14 Statistical analysis
    3 Results and discussion
        3.1 Characterization and properties of CHMCNs
        3.2 Biocompatibility and biodegradability
        3.3 Evaluation of drug delivery ability and responsive release behavior
        3.4  Anti-tumor efficacy in vitro
    4 Conclusions
    References

• Lanxin Meng(College of Chemistry & Pharmacy, Northwest A&F University, Yangling 712100, Shanxi, China)
• Shiguo Sun(College of Chemistry & Pharmacy, Northwest A&F University, Yangling 712100, Shanxi, China, School of Chemistry and Chemical Engineering, State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, Shihezi 832003, Xinjiang, China, Key Laboratory of Xinjiang phytomedicine Resource and Utilization, Ministry of Education, Shihezi University, Shihezi 832003, Xinjiang, China) Corresponding author
• Yuling Zhang(School of Chemistry and Chemical Engineering, State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, Shihezi 832003, Xinjiang, China, Key Laboratory of Xinjiang phytomedicine Resource and Utilization, Ministry of Education, Shihezi University, Shihezi 832003, Xinjiang, China)
• Zhihao Zhao(School of Chemistry and Chemical Engineering, State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, Shihezi 832003, Xinjiang, China, Key Laboratory of Xinjiang phytomedicine Resource and Utilization, Ministry of Education, Shihezi University, Shihezi 832003, Xinjiang, China)
• Yanbing Chen(School of Chemistry and Chemical Engineering, State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, Shihezi 832003, Xinjiang, China, Key Laboratory of Xinjiang phytomedicine Resource and Utilization, Ministry of Education, Shihezi University, Shihezi 832003, Xinjiang, China)
• Xiao Su(School of Chemistry and Chemical Engineering, State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, Shihezi 832003, Xinjiang, China, Key Laboratory of Xinjiang phytomedicine Resource and Utilization, Ministry of Education, Shihezi University, Shihezi 832003, Xinjiang, China)
• Zhenzhen Xie(School of Chemistry and Chemical Engineering, State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, Shihezi 832003, Xinjiang, China, Key Laboratory of Xinjiang phytomedicine Resource and Utilization, Ministry of Education, Shihezi University, Shihezi 832003, Xinjiang, China)
• Zhiyong Liu(School of Chemistry and Chemical Engineering, State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, Shihezi 832003, Xinjiang, China, Key Laboratory of Xinjiang phytomedicine Resource and Utilization, Ministry of Education, Shihezi University, Shihezi 832003, Xinjiang, China)
• Jiaru Zhang(Xinjiang Uygur Autonomous Region Drug Evaluation and Inspection Center, Urumqi 830000, Xinjiang, China, School of Chemistry and Chemical Engineering, State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, Shihezi 832003, Xinjiang, China, Key Laboratory of Xinjiang phytomedicine Resource and Utilization, Ministry of Education, Shihezi University, Shihezi 832003, Xinjiang, China)