Theranostic\nNanoplatform Based on Polydopamine-Coated\nMagnetic Mesoporous Silicon for Precise Cancer Triplex Nanotherapy\nand Multimodal Imaging

Although targeted therapy has revolutionized oncotherapy,\nengineering\na versatile oncotherapy nanoplatform integrating both diagnostics\nand therapeutics has always been an intractable challenge to overcome\nthe limitations of monotherapy. Herein, a theranostics platform based\non DI/MP-MB has successfully realized the fluorescence detection of\ndisease marker miR-21 and the gene/photothermal/chemo triple synergetic\ncancer therapy, which can trace the tumor through photothermal and\nfluorescence dual-mode imaging and overcome the limitations of monotherapy\nto improve the treatment efficiency of tumors. DI/MP-MB was prepared\nby magnetic mesoporous silicon nanoparticles (M-MSNs) loaded with\ndoxorubicin (Dox) and new indocyanine green (IR820), and subsequently\ncoating polydopamine as a “gatekeeper”, followed by\nthe surface adsorbed with molecular beacons capable of targeting miR-21\nfor responsive imaging. Under the action of enhanced permeability\nretention and external magnetic field, DI/MP-MB were targeted and\nselectively accumulated in the tumor. MiR-21 MB hybridized with miR-21\nto form a double strand, which led to the desorption of miR-21 MB\nfrom the polydopamine surface and the fluorescence recovery to realize\ngene silencing and fluorescence imaging for tracking the treatment\nprocess. Meanwhile, with the response to the near-infrared irradiation\nand the tumor’s microacid environment, the outer layer polydopamine\nwill decompose, releasing Dox and IR820 to realize chemotherapy and\nphotothermal therapy. Finally, the ability of DI/MP-MB to efficiently\nsuppress tumor growth was comprehensively assessed and validated both\nin vitro and in vivo. Noteworthily, the excellent anticancer efficiency\nby the synergistic effect of gene/photothermal/chemo triple therapy\nof DI/MP-MB makes it an ideal nanoplatform for tumor therapy and imaging.