(620h) Surface Design of Magnetic Composite Particles Via Lipid Coating for Cancer Cell Treatment

Magnetic composite particles (MCPs) composed of magnetic nanoparticles and base materials have advantages such as superparamagnetism, photothermal conversion ability, and excellent biocompatibility [Ref 1, Ref 2]. Therefore, MCPs have attracted attention for their application in photothermal therapy [Ref 3]. In this therapy, a substance able to convert light into heat is introduced into the target cells, and then cells are thermally killed by near infrared laser irradiation.

Lipid vesicles exhibit a variety of functions in drug delivery systems, depending on their lipid compositions. As example, SM102 (heptadecan-9-yl-8-((2-hydroxyethyl)(6-oxo-6-(undecyloxy)hexyl)amino)octanoate) is a pH responsive lipid, which can promotes endosomal escape of nano carriers after endocytosis [Ref 4]. Therefore, by coating the particle surface with a desired lipid membrane, it is expected to deliver dispersed MCPs inside cells and to control their dynamics by applying external field (e.g., direct current magnetic field [Ref 3]).

In this study, we developed a method to functionalize MCPs using lipid vesicles. Herein, DOTAP (1,2-dioleoyl-3-trimethylammonium-propane) and SM102 were used as building blocks of cationic vesicles. Silica-based MCPs (diameter: 200–300 nm, saturation magnetization: 10–20 emu/g) and cationic vesicles were coextruded using polycarbonate membrane (pore diameter: 400 nm), and the obtained lipid coated MCPs were purified via centrifugation. Zeta potentials of lipid coated MCPs were measured. DOTAP-coated MCPs (MCP@DOTAP) exhibited cationic properties at the pH ranges of 3–9 , while SM102-coated MCPs (MCP@SM102) exhibited cationic properties at the pH ranges below 8, suggesting the functionalization of MCPs by desired lipid. The fabricated particles were applied to HeLa cells. After 24 h incubation at 37℃, the particle-introduced cells were observed by confocal fluorescence microscopy. Pristine MCPs tend to be aggregated in HeLa cells, while lipid-coated MCPs were observed as a dispersion state. It was investigated the effect of coating MCPs with a cationic lipid membrane on the behavior of MCPs in HeLa cells.

[Ref 1] C. Suwabe et al., Colloid Polym. Sci., 294, 2079–2085 (2016)

[Ref 2] S. Cabana et al., Nanomaterials, 10, 1548 (2020)

[Ref 3] R. Kameda et al., ACS Appl. Nano Mater., 6, 3883 (2023)

[Ref 4] M. D. Buschmann et al., Vaccines, 9, 65 (2021)