Microgels Research Articles

Almond protein as Pickering emulsion stabilizer: Impact of microgel fabrication method and pH on emulsion stability

We evaluated the ability of almond proteins to produce Pickering emulsions (EM) stabilized by microgels (MG) fabricated by three different methods (heat treatment–HT, crosslinking with transglutaminase–TG or calcium–CA), at two pH levels (pH 3 or 7). Compared to pH 7, acidic pH significantly denatured almond proteins (ellipticity ∼0 mdeg), decreased absolute zeta potential values (10.5 to 18.6 mV at pH 3 and − 24.6 to −32.6 mV at pH 7), and free thiol content (114.64–131.60 μmol SH/g protein at pH 3 and 129.46–148.17 μmol SH/g protein at pH 7 – except in CA-crosslinked microgels, p > 0.05). These changes led to larger microgel sizes (D3,2pH3: 26.3–39.5 μm vs. D3,2pH7: 5.9–9.0 μm) with lower polydispersity (SpanpH3: ∼ 1.94 vs. SpanpH7: 2.32, excluding CA-based samples). Consequently, the Turbiscan Stability Index (TSI) was higher in acidic conditions for all emulsions, except for the calcium-containing formulation (EM_CApH3), emphasizing the critical role of calcium binding in maintaining emulsion stability in acidic environments. Microgels prepared via the traditional heat treatment method produced emulsions with intermediate stability (TSI ranging from 3.4 % to 5.1 % at 28 days of storage). Conversely, TG-crosslinked microgels led to unstable emulsions at pH 3, likely due to the lowest zeta potential (+4.2 mV), whereas at pH 7, the greatest stability was attributed to bridging flocculation that created a stable gel-like structure. Indeed, emulsions with lower TSI (EM_CApH3 = 1.8 %, EM_CApH7 = 2.3 % and EM_TGpH7 = 1.0 %, at 28 days of storage) also exhibited higher elastic modulus (G') over frequency sweep, indicating that the strong elastic network was relevant for emulsion stability (up to 28 days). This study, for the first time, demonstrated the production of stable almond-based Pickering emulsions, with properties modulated by the pH and method used to fabricate the microgels.

Effect of inulin on structural, physicochemical, and in vitro gastrointestinal tract release properties of core-shell hydrogel beads as a delivery system for vitamin B12

In this study, core-shell hydrogel beads were developed as a controlled-release delivery system for vitamin B12. Vitamin B12-loaded microgels (MG) were prepared using gellan gum (GG). Core-shell hydrogel beads were produced by incorporating MG into pea protein isolate (PPI) and sodium alginate (AL) matrix filled/coated with different concentrations (0 %, 1 %, 3 %, 5 %, and 10 %) of inulin (IN). Based on XRD analysis, MG was successfully incorporated into core-shell hydrogel beads. In FE-SEM and FT-IR analyses, the smoother surface and denser structure of the beads were observed as IN concentration increased due to hydrogen bonds between IN and the beads. The encapsulation efficiency increased from 68.64 % to 82.36 % as IN concentration increased from 0 % to 10 %, respectively. After exposure to simulated oral and gastric conditions, core-shell hydrogel beads exhibited a lower cumulative release than MG, and a more sustained release was observed as IN concentration increased in simulated intestinal conditions.

Enhancing interfacial elasticity via supramolecular microgel assembly for improved Pickering emulsions stability

We propose a new method to improve the interfacial elasticity of microgel-stabilised Pickering emulsions (PEs) by introducing supramolecular host-guest interactions to promote clustering among microgel particles. To this aim, microgels based on poly(N-isopropylacrylamide) (pNIPAM) are modified with 1-benzyl-3-vinylimidazolium bromide (BVI) to create pNIPAM-co-BVI microgels (MG). Cucurbit[8]uril (CB[8]) are introduced to form supramolecular BVI/CB[8] host-guest complexes. The introduction of CB[8] affects microgel spatial distribution at the interface of Pickering droplets, promoting the formation of monolayers of microgel clusters. These structures alter the interfacial viscoelasticity of the microgel monolayers, enhancing the resistance of (MG+CB[8])-stabilised interfaces to lateral and dilational deformations. PEs stabilised by microgels with the presence of CB[8] host-guest interactions exhibit improved stability over time. These results show the possibility of tuning the interfacial properties of microgel-laden interfaces by introducing supramolecular ternary complexes that can solely alter the interparticle interactions among microgels without significantly changing their morphology and deformability at the interface, thus providing a new route for improved emulsion stabilisation.

Interaction between stabilized droplets of different phases in the same continuous phase of an aqueous three-phase system.

Water-in-water (W/W) emulsions, also called aqueous two-phase systems, are formed by mixing two incompatible polymers in water that phase separate into two distinct phases. They can be stabilized by addition of colloidal particles. Droplets of the dispersed phase can be used to compartmentalize ingredients and induce localized reactions. By mixing more types of incompatible polymers, emulsions containing droplets of different phases can be formed that can potentially capture different ingredients. Here the interaction between dispersed droplets of different types was studied by gently mixing a W/W emulsion containing droplets rich in dextran (DEX) dispersed in a continuous phase rich in polyethylene oxide with an emulsion containing droplets rich in fish gelatin (GEL) dispersed in the same continuous medium. Bis-hydrophilic microgels (MG) consisting of DEX grafted with poly(N-isopropylacrylamide) were added and their effect on the stability of each binary emulsion was investigated. Interestingly, when two very stable emulsions were gently mixed, droplets of different types were observed with confocal scanning laser microscopy to coalesce immediately upon contact. In this manner, Janus-type droplets were formed containing a DEX and a GEL compartment with no MG at the GEL/DEX interface that further associated into strings of alternating droplets. Contact angles between the different phases in emulsions with and without MG were compared and used to determine the effect of the microgels on the interfacial tension between the phases.

Water-sensitive fluorescent microgel inks to produce verifiable information for highly secured anti-counterfeiting.

The decryption and verification of encrypted information via a simple and efficient method is always difficult and challenging in the field of information security. Herein, a series of water-sensitive fluorescent microgels are fabricated for highly secured anti-counterfeiting with authenticity identification. The initial negatively charged microgels (MG) are made up of N-isopropylacrylamide (NIPAM), acrylic acid (AAc) and anthracen-9-yl acrylate (9-ANA, blue fluorescent monomer). The prepared MGs can bind cationic fluorescent dyes such as 5-aminofluorescein (FITC, green fluorescent dye) and rhodamine B (Rh B, red fluorescent dye) via electrostatic interaction, emitting multi-fluorescent colors based on the fluorescence resonance energy transfer (FRET) process. Furthermore, the fluorescence colors of MG-derived systems can be rapidly changed by swelling in water, which can block the FRET process and change the aggregation state of dyes. With the assistance of inkjet printing, multi-color security patterns can be designed and encoded, which can be revealed by UV irradiation and further verified by water stimulation. This study has pioneered a novel strategy to verify the authenticity of decrypted information, which greatly improves the security level of information.

Bioinspired Multistimuli-Induced Synergistic Changes in Color and Shape of Hydrogel and Actuator Based on Fluorescent Microgels.

Fluorescent hydrogels have emerged as one of the most promising candidates for developing biomimetic materials and artificial intelligence owing to their unique fluorescence and responsive properties. However, it is still challenging to fabricate hydrogel that exhibits synergistic changes in fluorescence color and shape in response to multistimulus via a simple method. Herein, blue- and orange-emitting fluorescent microgels (MGs) both are designed and synthesized with pH-, thermal-, and cationic-sensitivity via one-step polymerization, respectively. The two fluorescent MGs are incorporated into transparent doubly crosslinked microgel (DX MG) hydrogels with a preset ratio. The DX MG hydrogels can tune the fluorescent color accompanied by size variation via subjecting to external multistimulus. Thus, DX MG hydrogels can be exploited for multiresponsive fluorescent bilayer actuators. The actuators can undergo complex shape deformation and color changes. Inspired by natural organisms, an artificial morning glory with color and size changes are showcased in response to buffer solutions of different pH values. Besides, an intelligent skin hydrogel, imitating natural calotes versicolor, by assembling four layers of DX MG with different ratios of MGs, is tailored. This work serves as an inspiration for the design and fabrication of novel biomimetic smart materials with synergistic functions.

Injectable Colloidal Hydrogels of N-Vinylformamide Microgels Dispersed in Covalently Interlinked pH-Responsive Methacrylic Acid-Based Microgels

Injectable hydrogels offer great potential to augment damaged or degenerated soft tissues. A key criterion for such gels is that their modulus is as close as possible to that of the target tissue. The majority of synthetic hydrogels have used low molecular weight polymer chains which may cause problems if they diffuse away from the injection site and/or increase the local osmotic pressure. We previously introduced a different approach of injecting preformed ultra-high molecular weight pH-responsive microgels (MGs) that interlink to form hydrogels. MGs are crosslinked polymer colloid particles that swell when the pH approaches the particle pKa. These colloidal hydrogels are termed doubly crosslinked microgels (DX MGs). The gel moduli of previous DX MGs were much greater than that reported for human nucleus pulposus (NP) tissue of the spinal intervertebral disk. Here, we replace some of the pH-responsive poly(ethyl acrylate-co-methacrylic acid) (PEA-MAA) MGs with hydrophilic non-ionic MGs based on poly(N-vinylformamide) (NVF). We investigate the morphology and mechanical properties of these new injectable composite DX MGs and show that the mechanical properties can be tuned by systematically varying the NVF MG content. Using this approach, the gel moduli close to that for NP tissue are achieved. These injectable new pH-responsive gels exhibit low cytotoxicity. Our work provides a potential new system for minimally invasive intervertebral disk augmentation.

Mesenchymal Stem Cell‐Laden Composite β Cell Porous Microgel for Diabetes Treatment

AbstractType 1 diabetes mellitus is a chronic metabolic condition characterized by the autoimmune damage of pancreatic β cells. As an alternative to continuous exogenous insulin administration of insulin, β cell transplantation is shown to provide an alternative approach for controlling hyperglycemia in diabetes. However, β cell transplantation faces significant challenges of low β cell proliferation and immunologic insults. Thus, novel approaches capable of promoting the islet microenvironment for sustainability is highly desired. This study develops mesenchymal stem cell (MSC)‐laden composite β cell porous microgels (MGs) to address sustainability for the treatment of diabetes. The MGs are prepared via microfluidic droplet templates encapsulating both MSCs and β cells with porogen for creating a porous structure. In addition to offering a suitable microenvironment for nutrient delivery, the porous structure promoted β cell growth and insulin secretion. The outstanding anti‐apoptotic and immunomodulatory roles of MSCs further provide a favorable environment for β cell survival and function. On this basis, the therapeutic performance of the MGs in reducing hyperglycemia and achieving sustained glycemic control in diabetic mice is demonstrated. Collectively, these results show that the novel MGs have great potential for the treatment of diabetes providing a promising platform for clinical β cell transplantation.

Current Advances of Polysaccharide-Based Nanogels and Microgels in Food and Biomedical Sciences.

Polysaccharides are natural polymers with hydrophilic, biocompatible and biodegradable characteristics and have many opportunities in the food and pharmaceutical sectors. This review focuses on the field of nano and microstructures whose internal structure is based on networked polysaccharide chains in 3D i.e., polysaccharide nanogels (NGs) and microgels (MGs). As it is observed the number of articles on NGs and MGs in peer reviewed scientific journals has been increasing over the last two decades. At the same time, the relative contribution of polysaccharides in this field is gaining place. This review focuses on the different applied methods for the fabrication of a variety of polysaccharide-based NGs and MGs and aims to highlight the recent advances on the subject and present their potentials and properties with regards to their integration in aspects of medicinal and food sciences. The presentation of the recent advances in the application of polysaccharide NGs and MGs is divided in materials with potential as emulsion stabilizers and materials with potential as carriers of bioactives. For applications in the medical sector the division is based on the fabrication processes and includes self-assembled, electrostatically complexed/ionically crosslinked and chemically crosslinked NGs and MGs. It is concluded that many advances are expected in the application of these polysaccharide-based materials and in particular as nutrient-loaded emulsion stabilizers, viscosity modifiers and co-assembled structures in combination with proteins.

Stabilization of amylopectin-pullulan water in water emulsions by Interacting protein particles

Water in water emulsions were prepared by mixing aqueous solutions of amylopectin (AMP) and pullulan (PUL) in the presence of whey protein microgels (MG). Attractive interaction between the MG was introduced by decreasing the pH from neutral towards their isoelectric pH either by adding HCl while stirring or progressively in-situ by adding glucono-δ-lactone (GDL). Decreasing the pH led to a change in the preference of the MG from the PUL phase to the AMP phase and to adsorption of the MG at the interface. The morphology of the emulsions was observed using confocal laser scanning microscopy. The morphology and stability of the emulsions depended strongly on the pH and differed when AMP droplets were dispersed in the PUL phase or vice versa. In some cases, stable weak emulsion gels were formed that flowed when tilted. In others, droplets remained dispersed in a liquid phase stabilized by a gelled interface layer of MG. The interaction between the MG was further modulated by adding small amounts of anionic polysaccharides that formed complexes with the MG below pH 5.6. This was found to influence the partitioning of the MG between the phases, as well as the stability and morphology of the emulsions.

Bisepoxide-Jeffamine microgel synthesis and application toward heterogeneous surface morphology for differential neuronal/non-neuronal cell responses in vitro

Herein, a new non-vinylic type of cationic microgels (MG) was readily prepared from ethylene glycol diglycidyl ether and Jeffamine T-403 in water. The MG was responsive to both temperature and pH, and oxidatively stable as demonstrated by the hydrogen peroxide study. Using glass as a model substrate, its surface was easily imparted with a heterogeneous morphology by simply adsorbing MG dispersed in basic solution. Specifically, the morphology features patches made of a monolayer of connected yet individually recognizable MG. Through in vitro cell studies, we show that a mere change of the extent of surface coverage by such a patchy morphology can strike a balance in promoting adhesion and differentiation of neuron-like PC-12 cells and primary cortical neurons of chick embryo, without soliciting proliferative response from non-neuronal cells of NIH3T3 fibroblast and CTX astrocyte. This simple yet unconventional surface morphology created by MG could be leveraged in the future as an alternative strategy for neural interface engineering.

Stem Cell‐Recruiting Injectable Microgels for Repairing Osteoarthritis

AbstractThe differentiation potentials and viability of stem cells are often impaired during cell isolation and delivery. Inspired by the phenomenon where islands can recruit seabirds for nesting, “cell island” microgels (MGs), that is, growth factor‐loaded methacrylated hyaluronic acid and heparin blend MGs, which can recruit endogenous stem cells and promote chondrogenic differentiation, are constructed using microfluidic technology and photopolymerization processes, followed by non‐covalently binding platelet‐derived growth factor‐BB (PDGF‐BB) and transforming growth factor‐beta3 (TGF‐β3). The loading efficiency of PDGF‐BB and TGF‐β3 are 96% and 91%, respectively. In vitro and in vivo experiments find that the “cell island” MGs can enhance the migratory capacity of cells and recruit them from their niche via releasing PDGF‐BB. Meanwhile, by using hyaluronic acid, the “cell island” MGs provide a suitable microenvironment for cell attachment and spreading. Furthermore, the “cell island” MGs induce chondrogenic differentiation of the recruited cells via releasing TGF‐β3 and present a promising therapeutic effect for osteoarthritis. In sum, this developed “cell island” MG might serve as a temporary “nest site” to allow the migration, adhesion, and differentiation of endogenous stem cells, which can be a promising candidate rather than the conventional cell‐seeded scaffolds for promoting tissue regeneration.

Effect of adding a third polysaccharide on the adsorption of protein microgels at the interface of polysaccharide-based water in water emulsions

HypothesisWater-in-water (W/W) emulsions are formed by mixing aqueous solutions of incompatible polymers and can in some cases be stabilized by addition of particles. The adsorption of particles at the interface of W/W emulsions is dictated by the interfacial tension between the two aqueous phases and between the particles and each phase. It should therefore be possible to induce and fine-tune adsorption by adding small amounts of a third polysaccharide that is compatible with one or both phases. ExperimentsW/W emulsions were formed by mixing aqueous solutions of pullulan (PUL), amylopectin (AMP), and protein microgels (MG). The microstructure and positioning of the MG were monitored using confocal laser scanning microscopy. The effect of adding small amounts of other types of polysaccharides on the adsorption of the MG at the interface and their partitioning between the phases was studied. FindingsThe addition of all polysaccharides led to a progressive shift of the MG from the PUL phase to the AMP phase and to adsorption of the MG at the interface when the partition was not extreme. The partition could be fine-tuned to be equal, in which case particles adsorbed at the interface even very close to the binodal. The findings were confirmed for another type of emulsion and particle.

Silicification of Amine-Epoxide Cationic Microgels: An In Vitro Investigation.

Herein, the applicability of an unconventional, non-vinylic type of amine-epoxide microgels (MGs) to promote silica deposition from tetraethyl orthosilicate (TEOS) was investigated. Simply mixing MGs with TEOS in water at 25 °C resulted in the formation of hybrid silica-MG particles (sMGs) as a function of silicification time. The sMGs were cationic with thermal-sensitive swelling capability. Extending silicification time to 24 h was shown to increase silica content to 43%. Besides, the sMGs became structurally more rigid to resist drying-induced deformation and exhibited a rugged surface texture. Mechanistically, the aminated nature of the MGs was proved beneficial for the success of their silicification, fulfilling dual functions of the catalyst for TEOS hydrolysis and template for silica deposition. Through electrostatic adsorption, the sMGs provided a facile yet robust option for surface modifications toward bone-related applications. Surface-induced mineralization in simulated biological fluids was observed with sMG-immobilized surfaces, where the presence of hydroxyapatite was characterized in the deposited apatite. In vitro MC3T3-E1 pre-osteoblast cell studies showed that cell adhesion, morphology, and proliferation could be influenced by both sMG types and their adsorption density. Of particular interest is the finding of cells exhibiting elongated and greatly polarized morphology on the surface with high adsorption density of sMGs of 43% silica. It was postulated that the rugged appearance of such sMGs could have presented a hierarchically structured surface toward cells, an interesting aspect to be further exploited for the engineering of cell-surface interactions.

Incorporation of Dual-Stimuli Responsive Microgels in Nanofibrous Membranes for Cancer Treatment by Magnetic Hyperthermia.

The delivery of multiple anti-cancer agents holds great promise for better treatments. The present work focuses on developing multifunctional materials for simultaneous and local combinatory treatment: Chemotherapy and hyperthermia. We first produced hybrid microgels (MG), synthesized by surfactant-free emulsion polymerization, consisting of Poly (N-isopropyl acrylamide) (PNIPAAm), chitosan (40 wt.%), and iron oxide nanoparticles (NPs) (5 wt.%) as the inorganic component. PNIPAAm MGs with a hydrodynamic diameter of about 1 μm (in their swollen state) were successfully synthesized. With the incorporation of chitosan and NPs in PNIPAAm MG, a decrease in MG diameter and swelling capacity was observed, without affecting their thermosensitivity. We then sought to produce biocompatible and mechanically robust membranes containing these dual-responsive MG. To achieve this, MG were incorporated in poly (vinyl pyrrolidone) (PVP) fibers through colloidal electrospinning. The presence of NPs in MG decreases the membrane swelling ratio from 10 to values between 6 and 7, and increases the material stiffness, raising its Young modulus from 20 to 35 MPa. Furthermore, magnetic hyperthermia assay shows that PVP-MG-NP composites perform better than any other formulation, with a temperature variation of about 1 °C. The present work demonstrates the potential of using multifunctional colloidal membranes for magnetic hyperthermia and may in the future be used as an alternative treatment for cancer.

Synthesis, parameters, properties and applications of responsive molecularly imprinted microgels: a review

Abstract Responsive molecularly imprinted microgels (MIGs) have gained a lot of interest due to their responsive specificity and selectivity for target compounds. Study on MIGs is rapidly increasing due to their quick responsive behavior in various stimuli like pH and temperature. MIGs show unique property of morphology control on in-situ synthesis of nanoparticles in response of variation in reactant concentration. Literature related to synthesis, parameters, characterization, applications and prospects of MIGs are critically reviewed here. Range of templates, monomers, initiators and crosslinkers are summarized for designing of desired MIGs. This review article describes effect of variation in reactants combination and composition on morphology, imprinting factor and percentage yield of MIGs. Hydrolysis of similar templates using MIGs is also described. Relation between percentage hydrolysis and hydrolysis time of targets at different temperatures and template:monomer ratio is also analyzed. Possible imprinting modes of ionic/non-ionic templates and its series are also generalized on the basis of previous literature. MIGs are investigated as efficient anchoring vehicles for adsorption, catalysis, bio-sensing, drug delivery, inhibition and detection.

In situ formation of tetraphenylethylene nano-structures on microgels inside living cells via reduction-responsive self-assembly.

Controlling the assembly of synthetic molecules in living systems is of significance for their adaptive applications. However, it is difficult to achieve, especially for composite self-assemblies, due to the complexity and dynamic change of the intracellular environment, and there exist technical difficulties for the direct visualization of organic and polymer self-assemblies. Herein, we demonstrate a novel strategy for the in situ formation of self-assembled micro-nano composite structures in a cell milieu using reduction-responsive microgels (MGs) as a platform. The MGs were prepared by a templating and crosslinking method using a synthetic amphiphlic polymer as the basic material and porous CaCO3 microparticles as the template. The aggregation-induced emission (AIE) tetraphenylethylene moieties and reduction-labile disulfide bonds in the MGs were employed as the self-assembly building blocks and triggering sites for the intracellular self-assembly, respectively. In the presence of reductive agents such as glutathione, nano-spikes were gradually formed on the MGs. After the MGs were internalized by cells, the in situ formation of microgel/nano-spike composite structures was evidenced by the enhanced fluorescence intensity and was further confirmed by direct transmission electron microscopy observation. This work provides an effective strategy to cope with the challenging task of achieving and probing controlled self-assembly in a cell milieu, leading to new insights into investigating biological self-assembly and promoting the development of micro-/nanomaterials by learning from nature.

Tumor localization of oncolytic adenovirus assisted by pH-degradable microgels with JQ1-mediated boosting replication and PD-L1 suppression for enhanced cancer therapy.

Oncolytic therapy is a fast-developing cancer treatment field based on the promising clinical performance from the selective tumor cell killing and induction of systemic antitumor immunity. The virotherapy efficacy, however, is strongly hindered by the limited virus propagation and negative immune regulation in the tumor microenvironments. To enhance the antitumor activity, we developed injectable pH-degradable PVA microgels encapsulated with oncolytic adenovirus (OA) by microfluidics for localized OA delivery and cancer treatments. PVA microgels were tailored with an OA encapsulation efficiency of 68% and exhibited a pH-dependent OA release as the microgel degradation at mildly acidic conditions. PVA microgels mediated fast viral release and increased replication in HEK293T and A549 cells at a lower pH, and the replication efficiency could be further reinforced by co-loading with one BET bromodomain inhibitor JQ1, inducing significant cytotoxicity against A549 cells. An in vivo study revealed that OA release was highly located at the tumor tissue assisted by PVA microgels, and the OA infection was also enhanced with the addition of JQ1 treatment, meanwhile greatly inhibiting the PD-L1 expression to overcome the immune suppression. OA/JQ1 co-encapsulated injectable microgels exhibited a superior in vivo antitumor activity on the A549 lung tumor-bearing mice by the combination of inhibited proliferation, amplified oncolysis, and potential immune regulation.

Risperidone-Loaded PLGA-Lipid Particles with Improved Release Kinetics: Manufacturing and Detailed Characterization by Electron Microscopy and Nano-CT.

For parenteral controlled drug release, the desired zero order release profile with no lag time is often difficult to achieve. To overcome the undesired lag time of the current commercial risperidone controlled release formulation, we developed PLGA–lipid microcapsules (MCs) and PLGA–lipid microgels (MGs). The lipid phase was composed of middle chain triglycerides (MCT) or isopropylmyristate (IPM). Hydroxystearic acid was used as an oleogelator. The three-dimensional inner structure of Risperidone-loaded MCs and MGs was assessed by using the invasive method of electron microscopy with focused ion beam cutting (FIB-SEM) and the noninvasive method of high-resolution nanoscale X-ray computed tomography (nano-CT). FIB-SEM and nano-CT measurements revealed the presence of highly dispersed spherical structures around two micrometres in size. Drug release kinetics did strongly depend on the used lipid phase and the presence or absence of hydroxystearic acid. We achieved a nearly zero order release without a lag time over 60 days with the MC-MCT formulation. In conclusion, the developed lipid-PLGA microparticles are attractive alternatives to pure PLGA-based particles. The advantages include improved release profiles, which can be easily tuned by the lipid composition.

Encapsulation of Iron Oxide Nanoparticles and Oil-in-Water Nanocarriers in Microgels with Biomedical Potential.

Here we report on the design and characterization of calcium-alginate microgels (MGs) containing positively charged iron oxide nanoparticles (IONPs) and negatively charged oil-in-water (O/W) nanocarriers (NCs). To provide ionic compatibility of IONPs with the negatively charged NCs and alginate in MGs, they were coated with the anionic polysaccharides alginate, carrageenan or sulfobutyl-β-cyclodextrin. The mixing of both nanostructures (coated-IONPs and O/W NCs) with alginate solutions provide homogeneous dispersions able to form spherical hydrogels with different sizes (250-1400 micrometers) and encapsulating the nanostructures with high efficiency. MGs loaded with both nanostructures were reactive to continuous (attractive interaction) and alternating magnetic field (heat release similar to non-encapsulated IONPs). The encapsulation of both nanostructures in MGs was maintained even after 7 days of storage at 40 °C. We postulate that the above results will be of interest for the design of hydrogel formulations with therapeutic applications.