Thermosensitive Core-Shell Fe3O4@poly(N-isopropylacrylamide) Nanogels for Enhanced Oil Recovery

Smart stimuli-responsive polysaccharide nanohydrogels for drug delivery: a review

Polysaccharides have found extensive utilization as biomaterials in drug delivery systems owing to their remarkable biocompatibility, simple functionalization, and inherent biological properties. Within the array of polysaccharide-based biomaterials, there is a growing fascination for self-assembled polysaccharide nanogels (NG) due to their ease of preparation and enhanced appeal across diverse biomedical appliances. Nanogel (or nanohydrogel), networks of nanoscale dimensions, are created by physically or chemically linking polymers together and have garnered immense interest as potential carriers for delivering drugs due to their favorable attributes. These include biocompatibility, high stability, the ability to adjust particle size, the capacity to load drugs, and their inherent potential to modify their surface to actively target specific cells or tissues via the attachment of ligands that can recognize corresponding receptors. Nanogels can be engineered to respond to specific stimuli, such as pH, temperature, light, or redox conditions, allowing controlled release of the encapsulated drugs. This intelligent targeting capability helps prevent drug accumulation in unintended tissues and reduces the potential side effects. Herein, an overview of nanogels is offered, comprising their methods of preparation and the design of stimulus-responsive nanogels that enable controlled release of drugs in response to specific stimuli.

Degradable Fe3O4-based nanocomposite for cascade reaction-enhanced anti-tumor therapy

Cascade catalytic therapy has been recognized as a promising cancer treatment strategy, which is due in part to the induced tumor apoptosis when converting intratumoral hydrogen peroxide (H₂O₂) into highly toxic hydroxyl radicals (˙OH) based on the Fenton or Fenton-like reactions. Moreover this is driven by the efficient catalysis of glucose oxidization associated with starving therapy. The natural glucose oxidase (GO _x ), recognized as a "star" enzyme catalyst involved in cancer treatment, can specially and efficiently catalyze the glucose oxidization into gluconic acid and H₂O₂. Herein, pH-responsive biodegradable cascade therapeutic nanocomposites (Fe₃O₄/GO _x -PLGA) with dual enzymatic catalytic features were designed to respond to the tumor microenvironment (TME) and to catalyze the cascade reaction (glucose oxidation and Fenton-like reaction) for inducing oxidase stress. The GO _x -motivated oxidation reaction could effectively consume intratumoral glucose to produce H₂O₂ for starvation therapy and the enriched H₂O₂ was subsequently converted into highly toxic ˙OH by a Fe₃O₄-mediated Fenton-like reaction for chemodynamic therapy (CDT). In addition, the acidity amplification owing to the generation of gluconic acid will in turn accelerate the degradation of the nanocomposite and initiate the Fe₃O₄-H₂O₂ reaction for enhancing CDT. The resultant cooperative cancer therapy was proven to provide highly efficient tumor inhibition on HeLa cells with minimal systemic toxicity. This cascade catalytic Fenton nanocomposite might provide a promising strategy for efficient cancer therapy.

Bifunctional folic-conjugated aspartic-modified Fe3O4 nanocarriers for efficient targeted anticancer drug delivery

Functionalization of nanocarriers has been considered the most promising way of ensuring an accurate and targeted drug delivery system. This study reports the synthesis of bifunctional folic-conjugated aspartic-modified Fe3O4 nanocarriers with an excellent ability to deliver doxorubicin (DOX), an anticancer drug, into the intercellular matrix. Here, the presence of amine and carboxylate groups enables aspartic acid (AA) to be used as an efficient anchoring molecule for the conjugation of folic acid (FA) (EDC-NHS coupling) and DOX (electrostatic interaction). Based on the results, surface functionalization showed little effect on the physicochemical properties of the nanoparticles but significantly influenced both the loading and release efficiency of DOX. This is primarily caused by the steric hindrance effect due to large and bulky FA molecules. Furthermore, in vitro MTT assay of B16-F1 cell lines revealed that FA conjugation was responsible for a significant increase in the cytotoxicity of DOX-loaded nanocarriers, which was also found to be proportional to AA concentration. This high cytotoxicity resulted from an efficient cellular uptake induced by the over-expressed folate receptors and fast pH triggered DOX release inside the target cell. Here, the lowest IC50 value of DOX-loaded nanocarriers was achieved at 2.814 ± 0.449 μg mL-1. Besides, further investigation also showed that the drug-loaded nanocarriers exhibited less or no toxicity against normal cells.