A high-loading drug delivery system based on magnetic nanomaterials modified by hyperbranched phenylboronic acid for tumor-targeting treatment with pH response.

To overcome the limited drug loading capacity of magnetic nanopharmaceuticals arising from the relatively large mass of the metal core, a high-loading drug delivery system based on amino-functionalized Fe3O4 magnetic nanospheres modified by hyperbranched phenylboronic acid (HPBA-Fe3O4) were prepared for the first time. The obtained nanomaterials were characterized by transmission electron microscopy, Fourier transform infrared, zeta potential, elemental analysis, vibrating sample magnetometry and X-ray diffraction analysis, and the results showed that hyperbranched phenylboronic acid (HPBA) were successfully grafted onto the surface of the magnetic nanospheres. The polymerization conditions, adsorption and desorption performance, and tumor-targeting ability of HPBA-Fe3O4 was investigated in detail through chemical and biological experiments. The drug loading amount and capacity of HPBA-Fe3O4 are 271.3 mg/g and 27.13%, respectively, which are 2.26 and 3.27 times greater than those of PBA-Fe3O4 and PEI-Fe3O4, and the thermodynamic fitting results further demonstrate the high drug loading ability of HPBA-Fe3O4. In vitro studies performed in U-87 MG malignant glioma cells and astrocytes via light and fluorescence microscopy analyses, cell counting kit-8 assays, and HPLC tests confirm the pH-sensitive release and tumor-targeted drug delivery capabilities of HPBA-Fe3O4. The facile fabrication of hyperbranched magnetic nanomaterials could be an alternative solution for designing high-loading, tumor cell-targeting and pH-responsive DDSs with high-mass cores.