Currently, cancer is the second largest cause of death worldwide and has reached critical levels. In spite of all the efforts, common treatments including chemotherapy, photodynamic therapy, and photothermal therapy suffer from various problems which limit their efficiency and performance. For this reason, different strategies are being explored which improve the efficiency of these traditional therapeutic methods or treat the tumor cells directly. One such strategy utilizing the Fenton reaction has been investigated by many groups for the possible treatment of cancer cells. This approach is based on the knowledge that high levels of hydrogen peroxide exist within cancer cells and can be used to catalyze the Fenton reaction, leading to cancer-killing reactive oxygen species. Analysis of the current literature has shown that, due to the diverse morphologies, different sizes, various chemical properties, and the tunable structure of nanoparticles, nanotechnology offers the most promising method to facilitate the Fenton reaction with cancer therapy. This review aims to highlight the use of the Fenton reaction using different nanoparticles to improve traditional cancer therapies and the emerging Fenton-based therapy, highlighting the obstacles, challenges, and promising developments in each of these areas.

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A novel reduced iron metal-organic framework nanoparticle with cytotoxicity specific to cancer cells is presented. This nanoparticle was prepared via a hydrothermal method, reduced using hydroquinone, and finally conjugated with folic acid (namely, rMOF-FA). The synthesized nanoparticle shows the controlled release of iron in an acidic ex-vivo environment. Iron present on the rMOF-FA and released into solution can react with high levels of hydrogen peroxide found specifically in cancer cells to increase the hydroxyl radical concentration. The hydroxyl radicals oxidize proteins, lipids, and/or DNA within the biological system to decrease cell viability. In vitro experiments demonstrate that this novel nanoparticle is cytotoxic to cancer cells (HeLa) through generation of OH inside the cells. At low concentrations of rMOF-FA, the cancer cell viability decreases dramatically, with no obvious reduction of normal cell (NIH-3T3) viability. The calculated half-maximum inhibitory concentration value (IC) was 43 μg/mL for HeLa cells, which was significantly higher than 105 μg/mL for NIH-3T3. This work thus demonstrates a new type of agent for controlled hydroxyl radical generation using the Fenton reaction to kill the tumor cells.

There is currently intense interest in new methods for understanding the fate of therapeutically-relevant cells, such as mesenchymal stem cells (MSCs). The absence of a confounding background signal and consequent unequivocal assignment makes 19F MRI one of the most attractive modalities for the tracking of injected cells in vivo. We describe here the synthesis of novel partly-fluorinated polymeric nanoparticles with small size and high fluorine content as MRI agents. The polymers, constructed from perfluoropolyether methacrylate (PFPEMA) and oligo(ethylene glycol) methacrylate (OEGMA) have favourable cell uptake profiles and excellent MRI performance. To facilitate cell studies the polymer was further conjugated with a fluorescent dye creating a dual-modal imaging agent. The efficacy of labelling of MSCs was assessed using 19F NMR, flow cytometry and confocal microscopy. The labelling efficiency of 2.6 ± 0.1 × 1012 19F atoms per cell, and viability of >90% demonstrates high uptake and good tolerance by the cells. This loading translates to a minimum 19F MRI detection sensitivity of ∼7.4 × 103 cells per voxel. Importantly, preliminary in vivo data demonstrate that labelled cells can be readily detected within a short acquisition scan period (12 minutes). Hence, these copolymers show outstanding potential for 19F MRI cellular tracking and for quantification of non-phagocytic and therapeutically-relevant cells in vivo.

Defect-free and cross-linked ultra-thin (sub 100 nm) film composite membranes have been prepared. The membrane materials formed exhibited significantly high CO2 permeances of over 1200 GPU as well as excellent CO2/N2 selectivity of over 40.