A multifunctional nanocomposite theranostic system is constructed of manganese oxide (Mn3O4) nanoparticles (NPs), as a tumor diagnostic agent, in conjunction with polyacrylic acid (PAA), as a pH-sensitive drug delivery agent, and methotrexate (MTX), as a model of targeting agent and anticancer drug. Physicochemical characteristics of the Mn3O4@PAA/MTX system is studied in detail by several techniques, including X-ray and Auger photoelectron spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and electrochemical methods. The system performance is studied based on (i) in-vitro MRI measurements to support efficiency of the Mn3O4@PAA NPs as a diagnostic agent, (ii) drug release performance of the Mn3O4@PAA/MTX NPs at pHs of 5.4 and 7.4 through in-vitro method to evaluate application of the NPs as pH-sensitive nanocarriers for MTX, and (iii) impedance spectroscopy measurements to show Mn3O4@PAA/MTX NPs affinity for capturing of cancer cells. The results show that (i) Mn3O4@PAA NPs can be used as a contrast agent in MRI measurements (r1 ≅ 6.5 mM-1 s-1), (ii) the MTX, loaded on Mn3O4@PAA NPs, is released faster and more efficient at pH 5.4 than 7.4, and (iii) the GC-Mn3O4@PAA/MTX electrode system captures the 4T1 cells 3.32 times larger than L929 cells.
Keywords: MRI measurements; Mn(3)O(4) nanoparticles; Polyacrylic acid; Theranostic system; pH-sensitive polymer.
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