Methotrexate-Transferrin-Functionalized Fe(Salen)-Polypyrrole Nanocomposites for Targeted Photo-/Magneto-Thermal Cancer Treatments

Construction of Methotrexate-Loaded Bi2S3 Coated with Fe/Mn-Bimetallic Doped ZIF-8 Nanocomposites for Cancer Treatment Through the Synergistic Effects of Photothermal/Chemodynamic/Chemotherapy

A combination of therapeutic modalities in a single nanostructure is crucial for a successful cancer treatment. Synergistic photothermal therapy (PTT) can enhance the effects of chemodynamic therapy (CDT) and chemotherapy, which could intensify the therapeutic efficacy to induce cancer cell apoptosis. In this study, Fe and Mn on a zeolitic imidazolate framework (ZIF-8) (Fe/Mn-ZIF-8; FMZ) were synthesized through ion deposition. Furthermore, bismuth sulfide nanorods (Bi2S3 NRs; BS NRs) were synthesized via a hydrothermal process and coated onto FMZ to generate the core-shell structure of the Bi2S3@FMZ nanoparticles (B@FMZ). Next, methotrexate (MTX) was loaded effectively onto the porous surface of ZIF-8 to form the B@FMZ/MTX nanoparticles. The Fenton-like reaction catalyzes Fe2+/Mn2+ ions by decomposing H2O2 in the tumor microenvironment, resulting in the formation of toxic hydroxyl radicals (·OH), which promotes the CDT effect of killing cancer cells. Furthermore, under 808 nm laser irradiation, these B@FMZ nanoparticles showed a strong PTT effect, owing to the presence of intense BS NRs as a photothermal agent. The B@FMZ nanoparticles exhibited a prominent drug release efficiency of 87.25% at pH 5.5 under near-infrared laser irradiation due to the PTT effect can promote the drug delivery performance. The B@FMZ nanoparticles were subjected to dual-modal imaging, guided magnetic resonance imaging, and X-ray computed tomography imaging. Both in vitro and in vivo results suggested that the B@FMZ/MTX nanoparticles exhibited enhanced antitumor effects through the combined therapeutic effects of PTT, CDT, and chemotherapy. Therefore, these nanoparticles exhibit good biocompatibility and are promising candidates for cancer treatment.

Evolution of Gold and Iron Oxide Nanoparticles in Conjugates with Methotrexate: Synthesis and Anticancer Effects

Au and Fe nanoparticles and their conjugates with the drug methotrexate were obtained by an environmentally safe method of metal-vapor synthesis (MVS). The materials were characterized by transmission and scanning electron microscopy (TEM, SEM), X-ray photoelectron spectroscopy (XPS), and small-angle X-ray scattering using synchrotron radiation (SAXS). The use of acetone as an organic reagent in the MVS makes it possible to obtain Au and Fe particles with an average size of 8.3 and 1.8 nm, respectively, which was established by TEM. It was found that Au, both in the NPs and the composite with methotrexate, was in the Au⁰, Au⁺ and Au³⁺ states. The Au 4f spectra for Au-containing systems are very close. The effect of methotrexate was manifested in a slight decrease in the proportion of the Au⁰ state-from 0.81 to 0.76. In the Fe NPs, the main state is the Fe³⁺ state, and the Fe²⁺ state is also present in a small amount. The analysis of samples by SAXS registered highly heterogeneous populations of metal nanoparticles coexisting with a wide proportion of large aggregates, the number of which increased significantly in the presence of methotrexate. For Au conjugates with methotrexate, a very wide asymmetric fraction with sizes up to 60 nm and a maximum of ~4 nm has been registered. In the case of Fe, the main fraction consists of particles with a radius of 4.6 nm. The main fraction consists of aggregates up to 10 nm. The size of the aggregates varies in the range of 20-50 nm. In the presence of methotrexate, the number of aggregates increases. The cytotoxicity and anticancer activity of the obtained nanomaterials were determined by MTT and NR assays. Fe conjugates with methotrexate showed the highest toxicity against the lung adenocarcinoma cell line and Au nanoparticles loaded with methotrexate affected the human colon adenocarcinoma cell line. Both conjugates displayed lysosome-specific toxicity against the A549 cancer cell line after 120 h of culture. The obtained materials may be promising for the creation of improved agents for cancer treatment.

Small molecules as cancer targeting ligands: Shifting the paradigm

Conventional chemotherapeutics exploration is hampered due to their nonspecific distribution leading to unintended serious toxicity. Toxicity is so severe that deciding to go for chemotherapy becomes a question of concern for many terminally ill cancer patients. However, with evolving times nanotechnology assisted in reducing the haywire distribution and channelizing the movement of drug-enclosing drug delivery systems to cancer cells to a greater extent, yet toxicity issues still could not be obliterated. Thus, active targeting appeared as a refuge, where ligands actively or specifically deliver linked chemotherapeutics and carriers to cancer cells. For a very long time, large molecule weight/macromolecular ligands (peptides and big polymers) were considered the first choice for ligand-directed active cancer targeting, due to their specificity towards overexpressed native cancer receptors. However, complex characterization, instability, and the expensive nature demanded to reconnoitre better alternatives for macromolecule ligands. The concept of small molecules as ligands emerged from the idea that few chemical molecules including chemotherapeutics have a higher affinity for cancer receptors, which are overexpressed on cell membranes, and may have the ability to assist in drug cellular uptake through endocytosis. But now the question is, can they assist the conjugated macro cargos to enter the cell or not? This present review will provide a holistic overview of the small molecule ligands explored till now.

Magnetic Control of Cells by Chemical Fabrication of Melanin

Melanin is an organic material biosynthesized from tyrosine in pigment-producing cells. The present study reports a simple method to generate tailored functional materials in mammalian cells by chemically fabricating intracellular melanin. Our approach exploits synthetic tyrosine derivatives to hijack the melanin biosynthesis pathway in pigment-producing cells. Its application was exemplified by synthesizing and using a paramagnetic tyrosine derivative, m-YR, which endowed melanoma cells with responsiveness to external magnetic fields. The mechanical force generated by the magnet-responsive melanin forced the cells to elongate and align parallel to the magnetic power lines. Critically, even non-pigment cells were similarly remote-controlled by external magnetic fields once engineered to express tyrosinase and treated with m-YR, suggesting the versatility of the approach. The present methodology may potentially provide a new avenue for mechanobiology and magnetogenetic studies and a framework for magnetic control of specific cells.