Permeability of the Composite Magnetic Microcapsules Triggered by a Non-Heating Low-Frequency Magnetic Field

Combination Using Magnetic Iron Oxide Nanoparticles and Magnetic Field for Cancer Therapy

Iron oxide nanoparticles (MNPs) demonstrate notable benefits in magnetic induction, attributed to their distinctive physical and chemical attributes. Emerging cancer treatment utilizing magnetic fields have also gathered increasing attention in the biomedical field. However, the defects of difficult dispersion and poor biocompatibility of MNPs seriously hinder their application. In order to overcome its inherent defects and maximize the therapeutic potential of MNPs, various functionalized MNPs have been developed, and numerous combined treatment methods based on MNPs have been widely studied. In this review, we compare and analyze the common nanoparticles based on MNPs with different sizes, shapes, and functional modifications. Additionally, we introduced the therapeutic mechanisms of the strategies, such as magnetically controlled targeting, magnetic hyperthermia, and magneto-mechanical effect, which based on the unique magnetic induction capabilities of MNPs. Finally, main challenges of MNPs as smart nanomaterials were also discussed. This review seeks to offer a thorough overview of MNPs in biomedicine and a new sight for their application in tumor treatment.

Pilot-scale co-precipitation synthesis of a novel active ingredient made of ultrasmall iron (oxyhydr)oxide nanoparticles for the treatment of hyperphosphatemia

Due to its simplicity, co-precipitation is the most commonly used method for producing iron (oxyhydr)oxide nanoparticles. However, it is reported to be sensitive to changes in process parameters, which complicates scale-up and is why only volumes up to 1.2 L have been described in the literature. This study aims to demonstrate the scale-up of a co-precipitation synthesis to 100 L using the example of a new phosphate-binding active ingredient based on iron (oxyhydr)oxide. The synthesis was shown to be very robust to changes in synthesis parameters and stirrer geometries. The in vitro phosphate-binding efficacy and the yield were maintained in all five scales tested. Only the content of the components in the nanoparticles varied slightly. However, Mössbauer spectroscopy, dynamic light scattering (DLS), and attenuated total reflection Fourier transform infrared spectroscopy (FT-IR) revealed no evidence of structural changes, but a reduction in the size of the iron (oxyhydr)oxide cores and the total core-shell nanoparticle sizes. Overall, this study has successfully demonstrated that ultrasmall iron (oxyhydr)oxide nanoparticles can be produced on a pilot scale by co-precipitation with a yield of >40 g L-1.

Surface Modification with Particles Coated or Made of Polymer Multilayers

The coating of particles or decomposable cores with polyelectrolytes via Layer-by-Layer (LbL) assembly creates free-standing LbL-coated functional particles. Due to the numerous functions that their polymers can bestow, the particles are preferentially selected for a plethora of applications, including, but not limited to coatings, cargo-carriers, drug delivery vehicles and fabric enhancements. The number of publications discussing the fabrication and usage of LbL-assembled particles has consistently increased over the last vicennial. However, past literature fails to either mention or expand upon how these LbL-assembled particles immobilize on to a solid surface. This review evaluates examples of LbL-assembled particles that have been immobilized on to solid surfaces. To aid in the formulation of a mechanism for immobilization, this review examines which forces and factors influence immobilization, and how the latter can be confirmed. The predominant forces in the immobilization of the particles studied here are the Coulombic, capillary, and adhesive forces; hydrogen bonding as well as van der Waal's and hydrophobic interactions are also considered. These are heavily dependent on the factors that influenced immobilization, such as the particle morphology and surface charge. The shape of the LbL particle is related to the particle core, whereas the charge was dependant on the outermost polyelectrolyte in the multilayer coating. The polyelectrolytes also determine the type of bonding that a particle can form with a solid surface. These can be via either physical (non-covalent) or chemical (covalent) bonds; the latter enforcing a stronger immobilization. This review proposes a fundamental theory for immobilization pathways and can be used to support future research in the field of surface patterning and for the general modification of solid surfaces with polymer-based nano- and micro-sized polymer structures.

Renal Artery Catheterization for Microcapsules' Targeted Delivery to the Mouse Kidney

The problem of reducing the side effects associated with drug distribution throughout the body in the treatment of various kidney diseases can be solved by effective targeted drug delivery. The method described herein involves injection of a drug encapsulated in polyelectrolyte capsules to achieve prolonged local release and long-term capillary retention of several hours while these capsules are administered via the renal artery. The proposed method does not imply disruption (puncture) of the renal artery or aorta and is suitable for long-term chronic experiments on mice. In this study, we compared how capsule size and dosage affect the target kidney blood flow. It has been established that an increase in the diameter of microcapsules by 29% (from 3.1 to 4.0 μm) requires a decrease in their concentration by at least 50% with the same suspension volume. The photoacoustic method, along with laser speckle contrast imaging, was shown to be useful for monitoring blood flow and selecting a safe dose. Capsules contribute to a longer retention of a macromolecular substance in the target kidney compared to its free form due to mechanical retention in capillaries and slow impregnation into surrounding tissues during the first 1-3 h, which was shown by fluorescence tomography and microscopy. At the same time, the ability of capillaries to perform almost complete "self-cleaning" from capsular shells during the first 12 h leads to the preservation of organ tissues in a normal state. The proposed strategy, which combines endovascular surgery and the injection of polymer microcapsules containing the active substance, can be successfully used to treat a wide range of nephropathies.

Polyelectrolyte Multilayered Capsules as Biomedical Tools

Polyelectrolyte multilayered capsules (PEMUCs) obtained using the Layer-by-Layer (LbL) method have become powerful tools for different biomedical applications, which include drug delivery, theranosis or biosensing. However, the exploitation of PEMUCs in the biomedical field requires a deep understanding of the most fundamental bases underlying their assembly processes, and the control of their properties to fabricate novel materials with optimized ability for specific targeting and therapeutic capacity. This review presents an updated perspective on the multiple avenues opened for the application of PEMUCs to the biomedical field, aiming to highlight some of the most important advantages offered by the LbL method for the fabrication of platforms for their use in the detection and treatment of different diseases.