With rapid advances in nanomedicine, magnetic nanoparticles (MNPs) have emerged as a promising theranostic tool in biomedical applications, including diagnostic imaging, drug delivery and novel therapeutics. Significant preclinical and clinical research has explored their functionalization, targeted delivery, controllable drug release and image-guided capabilities. To further develop MNPs for theranostic applications and clinical translation in the future, we attempt to provide an overview of the recent advances in the development and application of MNPs for drug delivery, specifically focusing on the topics concerning the importance of biomarker targeting for personalized therapy and the unique magnetic and contrast-enhancing properties of theranostic MNPs that enable image-guided delivery. The common strategies and considerations to produce theranostic MNPs and incorporate payload drugs into MNP carriers are described. The notable examples are presented to demonstrate the advantages of MNPs in specific targeting and delivering under image guidance. Furthermore, current understanding of delivery mechanisms and challenges to achieve efficient therapeutic efficacy or diagnostic capability using MNP-based nanomedicine are discussed.

Gold-coated collagen nanofibers (GCNFs) were produced by a single-step reduction process and used for the growth and differentiation of human adult stem cells. The nanomaterials were characterized by a number of analytical techniques including electron microscopy and spectroscopy. They were found to be biocompatible and to improve the myocardial and neuronal differentiation process of the mesenchymal stem cells isolated from the placental chorionic component. The expression of specific differentiation markers (atrium, natriuretic peptide, actin F and actin monomer, glial fibrilary acidic protein, and neurofilaments) was investigated by immunocytochemistry.

The main goal of this investigation was to develop and test a new method of treatment for human hepatocellular carcinoma (HCC). We present a method of carbon nanotube-enhanced laser thermal ablation of HepG2 cells (human hepatocellular liver carcinoma cell line) based on a simple multiwalled carbon nanotube (MWCNT) carrier system, such as human serum albumin (HSA), and demonstrate its selective therapeutic efficacy compared with normal hepatocyte cells. Both HepG2 cells and hepatocytes were treated with HSA–MWCNTs at various concentrations and at various incubation times and further irradiated using a 2 W, 808 nm laser beam. Transmission electron, phase contrast, and confocal microscopy combined with immunochemical staining were used to demonstrate the selective internalization of HSA–MWCNTs via Gp60 receptors and the caveolin-mediated endocytosis inside HepG2 cells. The postirradiation apoptotic rate of HepG2 cells treated with HSA–MWCNTs ranged from 88.24% (for 50 mg/L) at 60 sec to 92.34% (for 50 mg/L) at 30 min. Significantly lower necrotic rates were obtained when human hepatocytes were treated with HSA–MWCNTs in a similar manner. Our results clearly show that HSA–MWCNTs selectively attach on the albondin (aka Gp60) receptor located on the HepG2 membrane, followed by an uptake through a caveolin-dependent endocytosis process. These unique results may represent a major step in liver cancer treatment using nanolocalized thermal ablation by laser heating.

Abstract:The low rate of survival for patients diagnosed with glioblastoma may be attributed to the existence of a subpopulation of cancer stem cells. These stem cells have certain properties that enable them to resist chemotherapeutic agents and ionizing radiation. Herein, we show that temozolomide-loaded gold nanostructures are efficient in reducing chemoresistance and destroy 82.7% of cancer stem cells compared with a 42% destruction rate using temozolomide alone. Measurements of in vitro cytotoxicity and apoptosis indicate that combination with gold facilitated the ability of temozolomide, an alkylating drug, to alter the resistance of these cancer stem cells, suggesting a new chemotherapy strategy for patients diagnosed with inoperable recurrent malignant glioma.

We report a one-step method for facile and sustainable synthesis of magnetic iron oxide nanorods (or IONRs) with mean lengths ranging from 25 to 50 nm and mean diameters ranging from 5 to 8 nm. The prepared IONRs are highly stable in aqueous media and can be surface functionalized for biomarker-targeted applications. This synthetic strategy involves the reaction of iron(III) acetylacetonate with polyethyleneimine in the presence of oleylamine and phenyl ether, followed by thermal decomposition. Importantly, the length and diameter as well as the aspect ratio of the prepared IONRs can be controlled by modulating the reaction parameters. We show that the resultant IONRs exhibit stronger magnetic properties compared to those of the widely used spherical iron oxide nanoparticles (IONPs) at the same iron content. The increased magnetic properties are dependent on the aspect ratio, with the magnetic saturation gradually increasing from 10 to 75 emu g when increasing length of the IONRs, 5 nm in diameter, from 25 to 50 nm. The magnetic resonance imaging (MRI) contrast-enhancing effect, as measured in terms of the transverse relaxivity, r, increased from 670.6 to 905.5 mM s, when increasing the length from 25 to 50 nm. When applied to the immunomagnetic cell separation of the transferrin receptor (TfR)-overexpressed medulloblastoma cells using transferrin (Tf) as the targeting ligand, Tf-conjugated IONRs can capture 92 ± 3% of the targeted cells under a given condition (2.0 × 10 cells/mL, 0.2 mg Fe/mL concentration of magnetic materials, and 2.5 min of incubation time) compared to only 37 ± 2% when using the spherical IONPs, and 14 ± 2% when using commercially available magnetic beads, significantly improving the efficiency of separating the targeted cells.