ABSTRACT
Size and surface modification are the two key factors affecting the effect of macrophages polarization induced by superparamagnetic iron oxide nanoparticles (SPIONs). The smaller the particle size, the better the polarization effect of SPIONs. Besides, the reasonable SPIONs surface modification method can also be used to enhance the polarization effect. In this study, SPIONs was prepared by solvothermal method and optimized by Box-Benhnken center combination design and response surface method. Furthermore, astragalus polysaccharide-superparamagnetic iron oxide nanocomplex (APS-SPIONs) was successfully constructed by EDC/NHS esterification method. The structure of APS-SPIONs was confirmed by dynamic light scatter and infrared spectrometer, and the contents of iron and polysaccharide were characterized by spectrophotometry. The effect of APS-SPIONs on inducing mouse macrophages RAW264.7 polarization was investigated by flow cytometry. The RAW264.7 macrophages-HepG2 human hepatoma cancer cells Transwell co-culture system was established to investigate APS-SPIONs improve anti-tumor function of macrophages in vitro, and the proliferation activity of APS-SPIONs on RAW264.7 detected by cell counting kit-8 (CCK-8) method. The results showed that the average particle size and zeta potential of APS-SPIONs were (82.93 ± 1.47) nm and (-24.00 ± 0.47) mV. Polysaccharide and Fe content were 8.69% and 7.04%, respectively. APS-SPIONs effectively induced the polarization of RAW264.7 into M1 type in vitro, improving the anti-tumor ability of macrophages in a co-culture system, without effecting the proliferation of macrophages. Our study provides a drug development strategy and preliminary research results to educate macrophages and reshape the tumor immune microenvironment to achieve tumor-killing effects.
ABSTRACT
Embolotherapy is a common method for clinical intervention in the treatment of diseases including aneurysms, arteriovenous malformations and solid tumors, and embolic agents are a decisive factor affecting the effect of embolization. Although various embolic agents like coils, microspheres, and Onyx have been used clinically, there are still some treatment limitations: such as weak blood vessel penetration, easy to aggregate, poor mechanical properties, adhesion to catheters, and the need for toxic solvents (e.g. dimethyl sulfoxide). In recent years, a number of studies have found that in situ hydrogels have good application prospects in the field of vascular embolization. When low viscosity precursor solution is injected into the targeted blood vessel via microcatheters, it will undergo a sol-gel transition through physical and/or chemical cross-linking to form hydrogel to block blood flow. In addition, these in situ hydrogels can load drugs by pore embedding, electrostatic interaction, chemical bonding, etc., and have excellent sustained-release properties. This review summarizes the research progress of injectable in situ hydrogel vascular embolic agents in the past ten years, with a view to provide references for the development of new embolic agents in the future.