With the potential uses of photothermal therapy (PTT) in cancer treatment with excellent efficacy, and the growing concerns about the nanotoxicity of hyperthermia agents such as carbon nanotubes and gold-based nanomaterials, the importance of searching for a biocompatible hyperthermia agent cannot be emphasized too much. In this work, a novel promising hyperthermia agent employing magnetic Fe₃O₄ particles with fairly low toxicity was proposed. This hyperthermia agent showed rapid heat generation under NIR irradiation. After modification with carboxymethyl chitosan (CMCTS), the obtained Fe₃O₄@CMCTS particles could disperse stably in PBS and serum without any aggregation. The modification of CMCTS could decrease the adsorption of bovine serum albumin (BSA) and improve the cellular uptake. In a comparative study with hollow gold nanospheres (HAuNS), Fe₃O₄@CMCTS particles exhibited a comparable photothermal effect and fairly low cytotoxicity. The in vivo magnetic resonance (MR) images of mice revealed that by attaching a magnet to the tumor, Fe₃O₄@CMCTS particles accumulated in the tumor after intravenous injection and showed a low distribution in the liver. After being exposed to a 808 nm laser for 5 min at a low power density of 1.5 W cm⁻², the tumors on Fe₃O₄@CMCTS-injected mice reached a temperature of ∼52 °C and were completely destroyed. Thus, a kind of multifunctional magnetic nanoparticle with extremely low toxicity and a simple structure for simultaneous MR imaging, targeted drug delivery and photothermal therapy can be easily fabricated.

Dual-core@shell-structured Fe₃O₄–NaYF₄@TiO₂nanocomposites as a magnetic targeting drug carrier for bioimaging and combined chemo-sonodynamic therapy.

Background: The aim of this work was to improve oral bioavailability. The uptake of a series of quaternary ammonium salt didodecyl dimethylammonium bromide (DMAB)-modified nanoparticles (with uniform sizes ranging from 50 nm to 300 nm) into heterogeneous human epithelial colorectal adenocarcinoma cells (Caco-2) and human colon adenocarcinoma cells (HT-29) was investigated. Methods: Coumarin-6 (C6) loaded poly (lactide-co-glycolide) (PLGA) nanoparticles were prepared with DMAB using the emulsion solvent diffusion method. The physicochemical properties and cellular uptake of these nanoparticles were studied. Deserno’s model was applied to explain the experimental observations. Results: The results showed that the surface modification of PLGA nanoparticles with DMAB notably improved the cellular uptake. The cellular uptake was size-dependent and had an optimal particle size of 100 nm. The experimental data was integrated numerically, and was in agreement with the theoretical model. Conclusion: These results indicated that the interactions between the charged nanoparticles and the cells resulted from various forces (eg, electrostatic forces, hydrophobic forces, bending and stretching forces, and limited receptor-mediated endocytosis), and the uptake of the nanoparticles occurred as a result of competition.

Improving the stability of drugs in the gastrointestinal tract and their penetration ability in the mucosal layer by implementing a nanoparticle delivery strategy is currently a research focus in the pharmaceutical field. However, for most drugs, nanoparticles failed in enhancing their oral absorption on a large scale (4 folds or above), which hinders their clinical application. Recently, several researchers have proved that the intestinal epithelial cell membrane crossing behaviors of nanoparticles deeply influenced their oral absorption, and relevant reviews were rare. In this paper, we systematically review the behaviors of nanoparticles in the intestinal epithelial cell membrane and mainly focus on their intracellular mechanism. The three key complex intracellular processes of nanoparticles are described: uptake by intestinal epithelial cells on the apical side, intracellular transport and basal side exocytosis. We believe that this review will help scientists understand the in vivo performance of nanoparticles in the intestinal epithelial cell membrane and assist in the design of novel strategies for further improving the bioavailability of nanoparticles.

Aim: To design pluronic F68 (PF68)-conjugated polyamidoamine (PAMAM) dendrimer conjugates for doxorubicin (DOX) delivery for overcoming multidrug resistance, and clarify the reversal mechanism. Materials & methods: A series of PAMAM-PF68 conjugates were designed. The antitumor activity of the DOX-loaded conjugates was evaluated against MCF-7/ADR cells, tumor spheroids and tumors. Several bioinformatics were detected to characterize the reversal mechanism. Results: Increased antitumor activity of the DOX-loaded conjugates was achieved in vitro and in vivo. The complexes induced more DOX accumulation via caveolae-mediated endocytosis. After escaping from the endosome/lysosome, the nuclear trafficking of DOX was achieved. Apoptosis was significantly increased by regulating mitochondrial function and gene expression. Conclusion: With optimized PF68 modification, PAMAM-PF68 conjugates can significantly overcome multidrug resistance in vitro and in vivo.