Yan Li,Youshen Wu,Cheng Luo,Feilong Yang,Lei Qin,Tao Fu,Guangquan Wei,Xiaowei Kang,Daocheng Wu
A comprehensive method combining polymerization-induced colloid aggregation, silica coating, and high-temperature calcination is developed for the preparation of micro-sized magnetic colloidal nanoparticle cluster/silica (CNC/silica) microspheres. The silica shell stabilizes the inner micro-sized γ-Fe2O3 nanoparticle clusters without phase transformation during high-temperature calcination instead of acting as anti-sintering agents. Their morphologies and inner structures are observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The material characteristics are investigated by Fourier transfer infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), powder X-ray diffraction (XRD) and vibrating-sample magnetometer (VSM). The biocompatibility and MRI enhancement effect of CNC/silica microspheres are also evaluated by MTT assay and MRI imaging. The prepared CNC/silica microspheres are narrow-dispersed with a wide size range of 1.8 μm to 5.0 μm. These microspheres also have the advantages of higher saturation magnetization (61.38 emu g−1), easily modifiable surfaces, good biocompatibility, high cell-label efficiencies, and significantly enhanced T2 effect in MRI, indicating their various potential applications in biomedical fields.
Hong Chen,Pingyu Wu,Zhenzhen Xiao,Ting Li,Minjuan Zhong,Yuqi Xie,Yanlan Liu
Chemodynamic therapy (CDT) has sparked increasing interest in selective cancer treatment. However, it remains a challenge to achieve an efficient and sustained therapeutic effect due to the restricted Fenton chemistry and deficient catalytic substrates within the tumor microenvironment (TME). Meanwhile, the lack of strategies to timely monitor the delivery and execution of CDT agents increases the risks of unwanted side effects. Here, we present that integration of TME-triggered cascade catalysis with tumor metabolism reprogramming to engineer activatable theranostic nanocatalysts is an effective way to tackle these challenges. A self-fueling and self-reported theranostic nanocatalyst is reported in this study by modifying multi-enzyme mimic MnO 2 nanosturctures with antisense oligonucleotides (ASO). This catalyst can produce free radicals through logic multi-enzymatic catalysis to induce oxidative damage to cancer cells, yet keeping inert in normal cells. Furthermore, the loaded ASO can silence MCT4 that overexpresses in tumor cells, resulting in efflux blockage of intracellular lactate and decrease of intracellular pH , which remarkably facilitates the cascade catalysis for amplified CDT. Meanwhile, such acidification triggers an MRI enhancement for reporting gene silencing. Results from in vivo testing further support the potential of our design for more effective CDT. This study offers different insights into the design and construction of advanced platforms for noninvasive imaging-guided treatment of a wide range of cancers.
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