Dual-pH/Magnetic-Field-Controlled Drug Delivery Systems Based on Fe3 O4 @SiO2 -Incorporated Salecan Graft Copolymer Composite Hydrogels

Fe3O4-SiO2 Mesoporous Core/Shell Nanoparticles for Magnetic Field-Induced Ibuprofen-Controlled Release

Hybrid magnetic nanoparticles made up of an iron oxide, Fe₃O₄, core and a mesoporous SiO₂ shell with high magnetization and a large surface area were proposed as an efficient drug delivery platform. The core/shell structure was synthesized by two seed-mediated growth steps combining solvothermal and sol-gel approaches and using organic molecules as a porous scaffolding template. The system presents a mean particle diameter of 30(5) nm (9 nm magnetic core diameter and 10 nm silica shell thickness) with superparamagnetic behavior, saturation magnetization of 32 emu/g, and a significant AC magnetic-field-induced heating response (SAR = 63 W/g_Fe3O4, measured at an amplitude of 400 Oe and a frequency of 307 kHz). Using ibuprofen as a model drug, the specific surface area (231 m²/g) of the porous structure exhibits a high molecule loading capacity (10 wt %), and controlled drug release efficiency (67%) can be achieved using the external AC magnetic field for short time periods (5 min), showing faster and higher drug desorption compared to that of similar stimulus-responsive iron oxide-based nanocarriers. In addition, it is demonstrated that the magnetic field-induced drug release shows higher efficiency compared to that of the sustained release at fixed temperatures (47 and 53% for 37 and 42 °C, respectively), considering that the maximum temperature reached during the exposure to the magnetic field is well below (31 °C). Therefore, it can be hypothesized that short periods of exposure to the oscillating field induce much greater heating within the nanoparticles than in the external solution.

Magnetic-responsive hydrogels: From strategic design to biomedical applications

Smart hydrogels which can respond to external stimuli have been widely focused with increasing interest. Thereinto, magnetic-responsive hydrogels that are prepared by embedding magnetic nanomaterials into hydrogel networks are more advantageous in biomedical applications due to their rapid magnetic response, precisely temporal and spatial control and non-invasively remote actuation. Upon the application of an external magnetic field, magnetic hydrogels can be actuated to perform multiple response modes such as locomotion, deformation and thermogenesis for therapeutic purposes without the limit of tissue penetration depth. This review summarizes the latest advances of magnetic-responsive hydrogels with focus on biomedical applications. The synthetic methods of magnetic hydrogels are firstly introduced. Then, the roles of different response modes of magnetic hydrogels played in different biomedical applications are emphatically discussed in detail. In the end, the current limitations and future perspectives for magnetic hydrogels are given.

The immuno-reactivity of polypseudorotaxane functionalized magnetic CDMNP-PEG-CD nanoparticles

pH‐magnetic dual‐responsive nanocomposites have been widely used in drug delivery and gene therapy. Recently, a polypseudorotaxane functionalized magnetic nanoparticle (MNP) was developed by synthesizing the magnetic nanoparticles with cyclodextrin (CD) molecules (CDMNP) via polyethylene glycol (PEG) (CDMNP‐PEG‐CD). The purpose of this study was to explore the antigenicity and immunogenicity of the nanoparticles in vivo prior to their further application explorations. Here, nanoparticles were assessed in vivo for retention, bio‐distribution and immuno‐reactivity. The results showed that, once administered intravenously, CDMNP‐PEG‐CD induced a temporary blood monocyte response and was cleared effectively from the body through the urine system in mice. The introduction of β‐CD and PEG/β‐CD polypseudorotaxane on SiO₂ magnetic nanoparticles (SOMNP) limited particle intramuscular dispersion after being injected into mouse gastrocnemius muscle (GN), which led to the prolonged local inflammation and muscle toxicity by CDMNP and CDMNP‐PEG‐CD. In addition, T cells were found to be more susceptible for β‐CD–modified CDMNP; however, polypseudorotaxane modification partially attenuated β‐CD–induced T cell response in the implanted muscle. Our results suggested that CDMNP‐PEG‐CD nanoparticles or the decomposition components have potential to prime antigen‐presenting cells and to break the muscle autoimmune tolerance.

The role of sodium alginate and gellan gum in the design of new drug delivery systems intended for antibiofilm activity of morin

The use of controlled drug delivery systems represents an alternative and promising strategy for the use of antimicrobials in the oral cavity. Microparticles, films and oral tablets based on alginate and gellan gum were developed also as a strategy to overcome the low aqueous solubility of morin. The systems were characterized in terms of morphological characteristics, mucoadhesion and in vitro drug release. Antibiofilm activity was analyzed for acidogenicity, microbial viability and the composition of the extracellular matrix of single-species biofilms. Scanning Electron Microscopy demonstrated that the microparticles were spherical, rough and compact. The film and the tablet presented smooth and continuous surface and in the inner of the tablet was porous. These systems were more mucoadhesive compared to the microparticles. The in vitro morin release profiles in artificial saliva demonstrated that the microparticles controlled the release better (39.6%), followed by the film (41.1%) and the tablet (91.4%) after 20 h of testing. The morin released from the systems reduced the acidogenicity, microbial viability, concentration of insoluble extracellular polysaccharides and dry weight of biofilms, when compared to the control group. The findings of this study showed that the morin has antibiofilm activity against cariogenic microorganisms.

Recent Advances in Magnetite Nanoparticle Functionalization for Nanomedicine

Functionalization of nanomaterials can enhance and modulate their properties and behaviour, enabling characteristics suitable for medical applications. Magnetite (Fe3O4) nanoparticles are one of the most popular types of nanomaterials used in this field, and many technologies being already translated in clinical practice. This article makes a summary of the surface modification and functionalization approaches presented lately in the scientific literature for improving or modulating magnetite nanoparticles for their applications in nanomedicine.

Polypseudorotaxane functionalized magnetic nanoparticles as a dual responsive carrier for roxithromycin delivery

A magnetic-pH dual responsive drug delivery system was prepared for antibacterial therapy to reduce the side effects on nonpathological cells or tissues. Iron oxide (Fe₃O₄) core was surface-functionalized with silane coupling agents to link β‑cyclodextrin (β-CD) (CDMNP), and a polypseudorotaxanes shell where polyethyleneglycol chains threaded much CD molecules was further prepared on the magnetic Fe₃O₄ core (CDMNP-PEG-CD) to enhance loading capacity of roxithromycin (ROX). CDMNP-PEG-CD with a hydrodynamic diameter of ~168 nm was cytocompatible, superparamagnetic, magnetic-responsive and stable for 180 min of storage. No significant interaction with serum albumin was shown for the nanocomposites. The in vitro release from ROX-loaded CDMNP-PEG-CD nanocomposites was about 76% of total drug within 30 min at pH 1.0, 1.6-fold of that at pH 7.4 and 2-fold of that at pH 8.0, presenting pH-responsive drug release behaviors. The nanocomposites showed positive antibacterial activity against both E. coli and S. aureus based on an agar diffusion method. The antibacterial activity of the nanocomposites was more sensitive against E. coli than S. aureus, and the inhibition halo against E. coli was 85% more than that of Fe₃O₄. CDMNP-PEG-CD nanocomposites allowed for the localization and fast concentration of hydrophobic drugs, providing a broad potential range of therapeutic applications.

A smart tumor microenvironment responsive nanoplatform based on upconversion nanoparticles for efficient multimodal imaging guided therapy

A smart tumor microenvironment responsive theranostic nanoplatform USPDF for UCL/CT dual-mode imaging and combination of chemotherapy and photothermal therapy.

Polysaccharide-based cationic hydrogels for dye adsorption

With advances in soft material design and engineering, naturally resourced polysaccharides have frequently been used to construct hydrogels because of their unique properties such as renewability, biodegradability and biocompatibility. In this work, we use a water-soluble microbial polysaccharide, salecan as a trapped natural polymer, poly(acrylamide-co-diallyldimethylammonium chloride) (PAD) as a functional matrix to prepare salecan/PAD hydrogels through a facile one-pot method. We employed a variety of spectroscopic techniques to probe the physicochemical properties of the designed hydrogels. The results demonstrated that salecan not only tuned the polarity of the PAD hydrogels, but also endowed them with adjustable water content. Subsequently, the adsorption performance of these hydrogels to methyl orange (MO) dye was investigated in detail. It was found that the salecan/PAD had the ability to remove MO from the surrounding aqueous solutions. In addition, adsorption kinetic data were nicely described by pseudo-second-order model and the adsorption isotherm data fitted well with the Freundlich equation. Having tailorable physicochemical properties coupled with the ability to uptake dye, these salecan-incorporated hydrogels could be promising platform for wastewater treatment and removal of heavy metal ions.