Tumor-penetrating Peptide Conjugated and Doxorubicin Loaded T1-T2 Dual Mode MRI Contrast Agents Nanoparticles for Tumor Theranostics

Multifunctional hybrids with versatile types of nanoparticles via self-assembly for complementary tumor therapy

Self-assembly is a promising method for the construction of multifunctional nanohybrids for biomedical application. In this work, self-assembled multifunctional nanohybrids with a controllable disassembly property have been successfully fabricated. By modification with cyclodextrin (CD)-decorated ethylenediamine-functionalized poly(glycidyl methacrylate) (PGED), CD groups and polycations were conjugated onto Au nanorods (Au NRs) or Fe3O4 nanoparticles (denoted as Au-PGED-CD or Fe3O4-PGED-CD), and different SiO2@Fe3O4-PGED (SFP) or SiO2@Au-PGED (SAP) nanohybrids were readily fabricated by the host-guest interaction between Au-PGED-CD or Fe3O4-PGED-CD and adamantyl (Ad)-functionalized chiral silica NRs under mild conditions. The DNA condensation ability of the polycation, the photothermal effects of Au NRs or Fe3O4 nanoparticles, as well as the unique structure of chiral silica NRs were integrated into one nanohybrid. Such nanohybrids have high gene transfection efficiency and low cytotoxicity. The photothermal effects of the nanohybrids could be utilized for photothermal therapy, and also could induce the disassembly of the nanohybrids, which is beneficial for DNA release. The nanohybrids with good transfection performance and excellent photothermal effects were further applied for multimodal therapy. This work presents a flexible strategy for the fabrication of multifunctional nanoplatforms with integration of the advantages of various types of nanoparticles.

Surface impact on nanoparticle-based magnetic resonance imaging contrast agents

Magnetic resonance imaging (MRI) is one of the most widely used diagnostic tools in the clinic. To improve imaging quality, MRI contrast agents, which can modulate local T1 and T2 relaxation times, are often injected prior to or during MRI scans. However, clinically used contrast agents, including Gd3+-based chelates and iron oxide nanoparticles (IONPs), afford mediocre contrast abilities. To address this issue, there has been extensive research on developing alternative MRI contrast agents with superior r1 and r2 relaxivities. These efforts are facilitated by the fast progress in nanotechnology, which allows for preparation of magnetic nanoparticles (NPs) with varied size, shape, crystallinity, and composition. Studies suggest that surface coatings can also largely affect T1 and T2 relaxations and can be tailored in favor of a high r1 or r2. However, the surface impact of NPs has been less emphasized. Herein, we review recent progress on developing NP-based T1 and T2 contrast agents, with a focus on the surface impact.