A biocompatible double network hydrogel based on poly (acrylic acid) grafted onto sodium alginate for doxorubicin hydrochloride anticancer drug release

This study involved the synthesis of a new biocompatible slow-release hydrogel named poly (acrylic acid) grafted onto sodium alginate (poly (AA-g-SA)) double network hydrogel (DNH). The hydrogel was created by polymerization of acrylic acid grafted onto sodium alginate polysaccharide using crosslinkers N,N'-methylenebisacrylamide and calcium chloride via free radical polymerization. The water absorbency of the poly (AA-g-SA) double network hydrogel was improved by optimizing the quantities of ammonium persulfate initiator, pH-sensitive monomer of acrylic acid, and crosslinkers. Various analytical techniques including attenuated total reflection Fourier-transformed infrared (ATR-FTIR), X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), and Brunauer-Emmett-Teller specific surface area analysis (BET) were used to characterize the synthesized hydrogels. The swelling and on-off switching behaviors of the hydrogels were investigated in deionized (DI) water at different temperatures and pH values. The optimum poly (AA-g-SA) DNH was tested for in vitro release of a hydrophilic chemotherapeutic drug, doxorubicin hydrochloride (DOX). The eco-friendly hydrogel favorably optimized the DOX slow release owing to its swelling rate, high absorption and regeneration capabilities. The findings of this study may have significant implications for medical and scientific research.

Self-Assembling Peptide-Based Magnetogels for the Removal of Heavy Metals from Water

In this study, we present the synthesis of a novel peptide-based magnetogel obtained through the encapsulation of γ-Fe2O3-polyacrylic acid (PAA) nanoparticles (γ-Fe2O3NPs) into a hydrogel matrix, used for enhancing the ability of the hydrogel to remove Cr(III), Co(II), and Ni(II) pollutants from water. Fmoc-Phe (Fluorenylmethoxycarbonyl-Phenylalanine) and diphenylalanine (Phe2) were used as starting reagents for the hydrogelator (Fmoc-Phe3) synthesis via an enzymatic method. The PAA-coated magnetic nanoparticles were synthesized in a separate step, using the co-precipitation method, and encapsulated into the peptide-based hydrogel. The resulting organic/inorganic hybrid system (γ-Fe2O3NPs-peptide) was characterized with different techniques, including FT-IR, Raman, UV-Vis, DLS, ζ-potential, XPS, FESEM-EDS, swelling ability tests, and rheology. Regarding the application in heavy metals removal from aqueous solutions, the behavior of the obtained magnetogel was compared to its precursors and the effect of the magnetic field was assessed. Four different systems were studied for the separation of heavy metal ions from aqueous solutions, including (1) γ-Fe2O3NPs stabilized with PAA, (γ-Fe2O3NPs); (2) Fmoc-Phe3 hydrogel (HG); (3) γ-Fe2O3NPs embedded in peptide magnetogel (γ-Fe2O3NPs@HG); and (4) γ-Fe2O3NPs@HG in the presence of an external magnetic field. To quantify the removal efficiency of these four model systems, the UV-Vis technique was employed as a fast, cheap, and versatile method. The results demonstrate that both Fmoc-Phe3 hydrogel and γ-Fe2O3NPs peptide magnetogel can efficiently remove all the tested pollutants from water. Interestingly, due to the presence of magnetic γ-Fe2O3NPs inside the hydrogel, the removal efficiency can be enhanced by applying an external magnetic field. The proposed magnetogel represents a smart multifunctional nanosystem with improved absorption efficiency and synergic effect upon applying an external magnetic field. These results are promising for potential environmental applications of γ-Fe2O3NPs-peptide magnetogels to the removal of pollutants from aqueous media.

Dissecting the Role of SMYD2 and Its Inhibitor (LLY-507) in the Treatment of Chemically Induced Non-Small Cell Lung Cancer (NSCLC) by Using Fe3O4 Nanoparticles Drug Delivery System

Cancer therapies based on nanoparticles with a loaded drug can overcome the problem of the drug's toxic effects in the traditional chemotherapeutic approach. In this study, we loaded LLY-507, a potent inhibitor of SMYD2, a methyltransferase enzyme, on iron oxide nanoparticles (IONPs). The prepared nanoparticles were characterized by microscopic analysis, loading efficiency, and drug release studies. Microscopic examination revealed an average grain size of 44 nm. The in vitro effect of LLY-507-IONPs, LLY-507, and IONPs was determined by MTT analysis (A549 cells) and hemolysis studies. IONPs have almost negative hemolytic activity in blood. The cell viability assay revealed IC50 values of both LLY-507 alone and LLY-507-loaded IONPs against A549; the lower value of the drug loaded on NPs (0.71 µg/mL alone and 0.53 µg/mL loaded on NPs) shows strong synergistic anticancer potential. We further tested the role of loaded NPs in a urethane-induced lung cancer mouse model (n = 40 mice in three independent trials, 20 mice in control group) to check the role of SMYD2 at various time points of lung cancer development. The loss of SMYD2 due to LLY-507 suppressed tumor growth, emphysema, hemorrhage, and congestion considerably. Hence, it can be concluded that the SMYD2 inhibitor has an anti-inflammatory effect on the mouse lung and suppresses tumor growth by inhibiting the SMYD2 protein.

Thermally and Magnetically Programmable Hydrogel Microactuators

The rapid development in micro-machinery enabled the investigation of smart materials that can embody fast response, programmable actuation, and flexibility to perform mechanical work. Soft magnetic actuators represent an interesting platform toward combining those properties. This study focuses on the synthesis of micro-actuators that respond to thermal and magnetic stimuli using micro-molding with a soft template as a fabrication technique. These microsystems consist of a hydrogel matrix loaded with anisotropic magnetic nanospindles. When a homogeneous magnetic field is applied, the nanospindles initially dispersed in monomer solution, align and assemble into dipolar chains. The ensuing UV-polymerization creates a network and conveniently arrests these nanostructures. Consequently, the magnetic dipole moment is coplanar with the microgel. Varying the shape, volume, and composition of the micro-actuators during synthesis provides a temperature-dependent control over the magnetic response and the polarizability. Beyond isotropic swelling, shaping the hydrogel as long thin ribbons with a passive layer on one side allows for differential swelling leading to bending and twisting deformations, for example, 2D- or 3D-spiral. These deformations involve a reversible amplification of the magnetic response and orientation of the hydrogels under magnetic field. Temperature control herewith determines the conformation and simultaneously the magnetic response of the micro-actuators.

Iron-Based Magnetic Nanosystems for Diagnostic Imaging and Drug Delivery: Towards Transformative Biomedical Applications

The advancement of biomedicine in a socioeconomically sustainable manner while achieving efficient patient-care is imperative to the health and well-being of society. Magnetic systems consisting of iron based nanosized components have gained prominence among researchers in a multitude of biomedical applications. This review focuses on recent trends in the areas of diagnostic imaging and drug delivery that have benefited from iron-incorporated nanosystems, especially in cancer treatment, diagnosis and wound care applications. Discussion on imaging will emphasise on developments in MRI technology and hyperthermia based diagnosis, while advanced material synthesis and targeted, triggered transport will be the focus for drug delivery. Insights onto the challenges in transforming these technologies into day-to-day applications will also be explored with perceptions onto potential for patient-centred healthcare.

Stimuli-responsive DNA-based hydrogels for biosensing applications

The base sequences of DNA are endowed with the rich structural and functional information and are available for the precise construction of the 2D and 3D macro products. The hydrogels formed by DNA are biocompatible, stable, tunable and biologically versatile, thus, these have a wide range of promising applications in bioanalysis and biomedicine. In particular, the stimuli-responsive DNA hydrogels (smart DNA hydrogels), which exhibit a reversible and switchable hydrogel to sol transition under different triggers, have emerged as smart materials for sensing. Thus far, the combination of the stimuli-responsive DNA hydrogels and multiple sensing platforms is considered as biocompatible and is useful as the flexible recognition components. A review of the stimuli-responsive DNA hydrogels and their biosensing applications has been presented in this study. The synthesis methods to prepare the DNA hydrogels have been introduced. Subsequently, the current status of the stimuli-responsive DNA hydrogels in biosensing has been described. The analytical mechanisms are further elaborated by the combination of the stimuli-responsive DNA hydrogels with the optical, electrochemical, point-of-care testing (POCT) and other detection platforms. In addition, the prospects of the application of the stimuli-responsive DNA hydrogels in biosensing are presented.

Smart/stimuli-responsive hydrogels: Cutting-edge platforms for tissue engineering and other biomedical applications

Recently, biomedicine and tissue regeneration have emerged as great advances that impacted the spectrum of healthcare. This left the door open for further improvement of their applications to revitalize the impaired tissues. Hence, restoring their functions. The implementation of therapeutic protocols that merge biomimetic scaffolds, bioactive molecules, and cells plays a pivotal role in this track. Smart/stimuli-responsive hydrogels are remarkable three-dimensional (3D) bioscaffolds intended for tissue engineering and other biomedical purposes. They can simulate the physicochemical, mechanical, and biological characters of the innate tissues. Also, they provide the aqueous conditions for cell growth, support 3D conformation, provide mechanical stability for the cells, and serve as potent delivery matrices for bioactive molecules. Many natural and artificial polymers were broadly utilized to design these intelligent platforms with novel advanced characteristics and tailored functionalities that fit such applications. In the present review, we highlighted the different types of smart/stimuli-responsive hydrogels with emphasis on their synthesis scheme. Besides, the mechanisms of their responsiveness to different stimuli were elaborated. Their potential for tissue engineering applications was discussed. Furthermore, their exploitation in other biomedical applications as targeted drug delivery, smart biosensors, actuators, 3D and 4D printing, and 3D cell culture were outlined. In addition, we threw light on smart self-healing hydrogels and their applications in biomedicine. Eventually, we presented their future perceptions in biomedical and tissue regeneration applications. Conclusively, current progress in the design of smart/stimuli-responsive hydrogels enhances their prospective to function as intelligent, and sophisticated systems in different biomedical applications.

Smart near infrared-responsive nanocomposite hydrogels for therapeutics and diagnostics

Nanocomposite (NC) hydrogels are emerging biomaterials that possess desirable and defined properties and functions for therapeutics and diagnostics. Particularly, nanoparticles (NPs) are employed as stimulus-transducers in NC hydrogels to facilitate the treatment process by providing controllable structural change and payload release under internal and external simulations. Among the various external stimuli, near-infrared (NIR) light has attracted considerable interest due to its minimal photo-damage, deep tissue penetration, low auto-fluorescence in living systems, facile on/off switch, easy remote and spatiotemporal control. In this study, we discuss four types of transducing nanomaterials used in NIR-responsive NC hydrogels, including metal-based nanoparticles, carbon-based nanomaterials, polydopamine nanoparticles (PDA NPs), and upconversion nanoparticles (UCNPs). This review provides an overview of the current progress in NIR-responsive NC hydrogels, focusing on their preparation, properties, applications, and future prospects.

Synthesis and efficacy of norfloxacin loaded onto magnetic hydrogel nanocomposites

A targeted drug delivery system based on biocompatible magnetic hydrogel nanocomposites consisting of poly[oligo(oxyethylene methacrylate)] anchored Fe₃O₄ nanoparticles was synthesized. The characteristics, thermal properties, morphology and magnetic properties were studied by XRD, FT-IR, TGA, SEM, TEM and VSM. A norfloxacin (NOR) anti-bacterial agent with a potential antitumor activity was immobilized into hydrogels, Fe₃O₄ nanoparticles and their magnetic hydrogel nanocomposites. The in vitro drug release manner of NOR was explored at different temperatures and pH values. The behavior of the drug release has been studied via different kinetic models. The antibacterial efficacy was tested against Streptococcus, Staphylococcus aureus, Kelebsella pneumonia and Escherichia coli via well diffusion method, and showed significant activity compared to the unloaded drug. Furthermore, an antitumor efficacy against HCT-116, HepG-2, PC3 and MCF-7 cancer cells revealed the highest cytotoxic efficacy with no influence on healthy cells. These nanodrugs, retaining both antibacterial and anticancer efficacy, have a talented therapeutic potential because of their selective cytotoxicity, connected with the ability to minimize the risk of bacterial infection in a cancer patient who is frequently immunocompromised.

Review on the advancements of magnetic gels: towards multifunctional magnetic liposome-hydrogel composites for biomedical applications

Magnetic gels have been gaining great attention in nanomedicine, as they combine features of hydrogels and magnetic nanoparticles into a single system. The incorporation of liposomes in magnetic gels further leads to a more robust multifunctional system enabling more functions and spatiotemporal control required for biomedical applications, which includes on-demand drug release. In this review, magnetic gels components are initially introduced, as well as an overview of advancements on the development, tuneability, manipulation and application of these materials. After a discussion of the advantages of combining hydrogels with liposomes, the properties, fabrication strategies and applications of magnetic liposome-hydrogel composites (magnetic lipogels or magnetolipogels) are reviewed. Overall, the progress of magnetic gels towards smart multifunctional materials are emphasized, considering the contributions for future developments.

Magnetic Iron Oxide Nanoparticle (IONP) Synthesis to Applications: Present and Future

Iron oxides are chemical compounds which have different polymorphic forms, including γ-Fe2O3 (maghemite), Fe3O4 (magnetite), and FeO (wustite). Among them, the most studied are γ-Fe2O3 and Fe3O4, as they possess extraordinary properties at the nanoscale (such as super paramagnetism, high specific surface area, biocompatible etc.), because at this size scale, the quantum effects affect matter behavior and optical, electrical and magnetic properties. Therefore, in the nanoscale, these materials become ideal for surface functionalization and modification in various applications such as separation techniques, magnetic sorting (cells and other biomolecules etc.), drug delivery, cancer hyperthermia, sensing etc., and also for increased surface area-to-volume ratio, which allows for excellent dispersibility in the solution form. The current methods used are partially and passively mixed reactants, and, thus, every reaction has a different proportion of all factors which causes further difficulties in reproducibility. Direct active and complete mixing and automated approaches could be solutions to this size- and shape-controlled synthesis, playing a key role in its exploitation for scientific or technological purposes. An ideal synthesis method should be able to allow reliable adjustment of parameters and control over the following: fluctuation in temperature; pH, stirring rate; particle distribution; size control; concentration; and control over nanoparticle shape and composition i.e., crystallinity, purity, and rapid screening. Iron oxide nanoparticle (IONP)-based available clinical applications are RNA/DNA extraction and detection of infectious bacteria and viruses. Such technologies are important at POC (point of care) diagnosis. IONPs can play a key role in these perspectives. Although there are various methods for synthesis of IONPs, one of the most crucial goals is to control size and properties with high reproducibility to accomplish successful applications. Using multiple characterization techniques to identify and confirm the oxide phase of iron can provide better characterization capability. It is very important to understand the in-depth IONP formation mechanism, enabling better control over parameters and overall reaction and, by extension, properties of IONPs. This work provides an in-depth overview of different properties, synthesis methods, and mechanisms of iron oxide nanoparticles (IONPs) formation, and the diverse range of their applications. Different characterization factors and strategies to confirm phase purity in the IONP synthesis field are reviewed. First, properties of IONPs and various synthesis routes with their merits and demerits are described. We also describe different synthesis strategies and formation mechanisms for IONPs such as for: wustite (FeO), hematite (α-Fe2O3), maghemite (ɤ-Fe2O3) and magnetite (Fe3O4). We also describe characterization of these nanoparticles and various applications in detail. In conclusion, we present a detailed overview on the properties, size-controlled synthesis, formation mechanisms and applications of IONPs.

Imparting Functionality to the Hydrogel by Magnetic-Field-Induced Nano-assembly and Macro-response

Hydrogels are composed of 3D hydrophilic networks with an abundance of water; they are analogous to biological soft tissues. Their unique physico-chemical properties endow hydrogels with great potential in many fields, including tissue engineering and flexible sensing. However, inadequate functionality, such as lack of rapid responsiveness, severely limits practical applications in many areas. Therefore, imparting functionality to the hydrogel is a hot research topic. The magnetic field, as an important physical field, provides a new strategy with a variety of advantages. Magnetic-field-induced ordered nano-assembly brought anisotropic properties and novel performance. Furthermore, the magnetic responsiveness of hydrogels with magnetic nanoparticles can lead to the generation of functionality under magnetic fields. Thus, we aim to systematically describe the significant effect of magnetic fields on the functionality of the hydrogel. In this review, magnetic-field-induced assembly of nanomaterials with different dimensions and resulting functional performance are introduced. The functionalities of hydrogels based on magnetic-field-induced macroscopic responses are also summarized. We believe this review will motivate more exploration of the application of magnetic fields to develop functional hydrogel materials.

Protein and Polysaccharide-Based Magnetic Composite Materials for Medical Applications

The combination of protein and polysaccharides with magnetic materials has been implemented in biomedical applications for decades. Proteins such as silk, collagen, and elastin and polysaccharides such as chitosan, cellulose, and alginate have been heavily used in composite biomaterials. The wide diversity in the structure of the materials including their primary monomer/amino acid sequences allow for tunable properties. Various types of these composites are highly regarded due to their biocompatible, thermal, and mechanical properties while retaining their biological characteristics. This review provides information on protein and polysaccharide materials combined with magnetic elements in the biomedical space showcasing the materials used, fabrication methods, and their subsequent applications in biomedical research.

Multifunctional magnetic iron oxide nanoparticles: diverse synthetic approaches, surface modifications, cytotoxicity towards biomedical and industrial applications

Magnetic iron oxide nanoparticles (MIONPs) play a major role in the emerging fields of nanotechnology to facilitate rapid advancements in biomedical and industrial platforms. The superparamagnetic properties of MIONPs and their environment friendly synthetic methods with well-defined particle size have become indispensable to obtain their full potential in a variety of applications ranging from cellular to diverse areas of biomedical science. Thus, the broadened scope and need for MIONPs in their demanding fields of applications required to be highlighted for a comprehensive understanding of their state-of-the-art. Many synthetic methods, however, do not entirely abolish their undesired cytotoxic effects caused by free radical production and high iron dosage. In addition, the agglomeration of MIONPs has also been a major problem. To alleviate these issues, suitable surface modification strategies adaptive to MIONPs has been suggested not only for the effective cytotoxicity control but also to minimize their agglomeration. The surface modification using inorganic and organic polymeric materials would represent an efficient strategy to utilize the diagnostic and therapeutic potentials of MIONPs in various human diseases including cancer. This review article elaborates the structural and magnetic properties of MIONPs, specifically magnetite, maghemite and hematite, followed by the important synthetic methods that can be exploited for biomedical approaches. The in vivo cytotoxic effects and the possible surface modifications employed to eliminate the cytotoxicity thereby enhancing the nanoparticle efficacy are also critically discussed. The roles and applications of surface modified MIONPs in medical and industrial platforms have been described for the benefits of global well-being.

Advances of magnetic nanoparticles in environmental application: environmental remediation and (bio)sensors as case studies

Nanotechnology is an emerging technique drawing increasing attentions in biomedical, electronic, environmental, and industrial application. Nanoparticles (NPs) possess unique optical, electrical, catalytic, and thermal properties, among which magnetic NPs (MNPs) are one of the most important groups with excellent superparamagnetism property, large surface area, and biocompatibility. In this review, methods for synthesizing and functionalizing MNPs are summarized and linked to their applications in environmental science as either adsorbents or catalysts for removing contaminants from environmental matrices, illustrating stronger reactivity, higher removal capacity, and fast kinetics. Additionally, we also comprehensively discuss the application of MNPs as (bio)sensors to selectively and sensitively detect the presence of environmental contaminants or pathogenic bacteria. This work summarizes the recent progresses of using MNPs as powerful tools in environmental science and engineering, raising their state-of-art application from environmental perspectives and benefiting researchers interested in NPs and environmental studies.

Chemical and photochemical DNA "gears" reversibly control stiffness, shape-memory, self-healing and controlled release properties of polyacrylamide hydrogels

A new class of stimuli-responsive DNA-based polyacrylamide hydrogels is described. They consist of glucosamine-boronate ester-crosslinked polyacrylamide chains being cooperatively bridged by stimuli-responsive nucleic acids. The triggered closure and dissociation of the stimuli-responsive units lead to switchable stiffness properties of the hydrogel. One hydrogel includes glucosamine-boronate esters and K⁺-ion-stabilized G-quadruplex units as cooperative crosslinkers. The hydrogel bridged by the two motifs reveals high stiffness, whereas the separation of the G-quadruplex bridges by 18-crown-6-ether yields a low stiffness hydrogel. By cyclic treatment of the hydrogel with K⁺-ions and 18-crown-6-ether, it is reversibly cycled between high and low stiffness states. The second system involves a photo-responsive hydrogel that reveals light-induced switchable stiffness functions. The polyacrylamide chains are cooperatively crosslinked by glucosamine-boronate esters and duplex nucleic acid bridges stabilized by trans-azobenzene intercalator units. The resulting hydrogel reveals high stiffness. Photoisomerization of the trans-azobenzene units to the cis-azobenzene states results in the separation of the duplex nucleic acid bridges and the formation of a low stiffness hydrogel. The control over the stiffness properties of the hydrogel matrices by means of K⁺-ions/crown ether or photoisomerizable trans-azobenzene/cis-azobenzene units is used to develop shape-memory, self-healing, and controlled drug-release hydrogel materials.

The chitosan hydrogels: from structure to function

This review places an emphasis on chitosan intelligent hydrogels. The fabrication methods and mechanisms are introduced in this review and the interactions of the formation of hydrogels with both physical and chemical bonds are also introduced. The relationship between the structural characteristics and the corresponding functions of stimuli-responsive characteristics, self-healing functions and high mechanical strength properties of the chitosan hydrogels are discussed in detail.

Monitoring Endothelial and Tissue Responses to Cobalt Ferrite Nanoparticles and Hybrid Hydrogels

Iron oxide nanoparticles (NPs) have been proposed for many biomedical applications as in vivo imaging and drug delivery in cancer treatment, but their toxicity is an ongoing concern. When NPs are intravenously administered, the endothelium represents the first barrier to tissue diffusion/penetration. However, there is little information about the biological effects of NPs on endothelial cells. In this work we showed that cobalt-ferrite (CoFe2O4) NPs affect endothelial cell integrity by increasing permeability, oxidative stress, inflammatory profile and by inducing cytoskeletal modifications. To overcome these problems, NPs have be loaded into biocompatible gels to form nanocomposite hybrid material (polysaccharide hydrogels containing magnetic NPs) that can be further conjugated with anticancer drugs to allow their release close to the target. The organic part of hybrid biomaterials is a carboxymethylcellulose (CMC) polymer, while the inorganic part consists of CoFe2O4 NPs coated with (3-aminopropyl)trimethoxysilane. The biological activity of these hybrid hydrogels was evaluated in vitro and in vivo. Our findings showed that hybrid hydrogels, instead of NPs alone, were not toxic on endothelial, stromal and epithelial cells, safe and biodegradable in vivo. In conclusion, biohydrogels with paramagnetic NPs as cross-linkers can be further exploited for antitumor drug loading and delivery systems.

Designed synthesis and surface engineering strategies of magnetic iron oxide nanoparticles for biomedical applications

Iron oxide nanoparticles (NPs) hold great promise for future biomedical applications because of their magnetic properties as well as other intrinsic properties such as low toxicity, colloidal stability, and surface engineering capability. Numerous related studies on iron oxide NPs have been conducted. Recent progress in nanochemistry has enabled fine control over the size, crystallinity, uniformity, and surface properties of iron oxide NPs. This review examines various synthetic approaches and surface engineering strategies for preparing naked and functional iron oxide NPs with different physicochemical properties. Growing interest in designed and surface-engineered iron oxide NPs with multifunctionalities was explored in in vitro/in vivo biomedical applications, focusing on their combined roles in bioseparation, as a biosensor, targeted-drug delivery, MR contrast agents, and magnetic fluid hyperthermia. This review outlines the limitations of extant surface engineering strategies and several developing strategies that may overcome these limitations. This study also details the promising future directions of this active research field.

Functional nucleic acid-based hydrogels for bioanalytical and biomedical applications

Hydrogels are crosslinked hydrophilic polymers that can absorb a large amount of water. By their hydrophilic, biocompatible and highly tunable nature, hydrogels can be tailored for applications in bioanalysis and biomedicine. Of particular interest are DNA-based hydrogels owing to the unique features of nucleic acids. Since the discovery of the DNA double helical structure, interest in DNA has expanded beyond its genetic role to applications in nanotechnology and materials science. In particular, DNA-based hydrogels present such remarkable features as stability, flexibility, precise programmability, stimuli-responsive DNA conformations, facile synthesis and modification. Moreover, functional nucleic acids (FNAs) have allowed the construction of hydrogels based on aptamers, DNAzymes, i-motif nanostructures, siRNAs and CpG oligodeoxynucleotides to provide additional molecular recognition, catalytic activities and therapeutic potential, making them key players in biological analysis and biomedical applications. To date, a variety of applications have been demonstrated with FNA-based hydrogels, including biosensing, environmental analysis, controlled drug release, cell adhesion and targeted cancer therapy. In this review, we focus on advances in the development of FNA-based hydrogels, which have fully incorporated both the unique features of FNAs and DNA-based hydrogels. We first introduce different strategies for constructing DNA-based hydrogels. Subsequently, various types of FNAs and the most recent developments of FNA-based hydrogels for bioanalytical and biomedical applications are described with some selected examples. Finally, the review provides an insight into the remaining challenges and future perspectives of FNA-based hydrogels.

Magnetic Gel Composites for Hyperthermia Cancer Therapy

Hyperthermia therapy is a medical treatment based on the exposition of body tissue to slightly higher temperatures than physiological (i.e., between 41 and 46 °C) to damage and kill cancer cells or to make them more susceptible to the effects of radiation and anti-cancer drugs. Among several methods suitable for heating tumor areas, magnetic hyperthermia involves the introduction of magnetic micro/nanoparticles into the tumor tissue, followed by the application of an external magnetic field at fixed frequency and amplitude. A very interesting approach for magnetic hyperthermia is the use of biocompatible thermo-responsive magnetic gels made by the incorporation of the magnetic particles into cross-linked polymer gels. Mainly because of the hysteresis loss from the magnetic particles subjected to a magnetic field, the temperature of the system goes up and, once the temperature crosses the lower critical solution temperature, thermo-responsive gels undergo large volume changes and may deliver anti-cancer drug molecules that have been previously entrapped in their networks. This tutorial review describes the main properties and formulations of magnetic gel composites conceived for magnetic hyperthermia therapy.

Magnetic resonance imaging of folic acid-coated magnetite nanoparticles reflects tissue biodistribution of long-acting antiretroviral therapy

Regimen adherence, systemic toxicities, and limited drug penetrance to viral reservoirs are obstacles limiting the effectiveness of antiretroviral therapy (ART). Our laboratory’s development of the monocyte-macrophage-targeted long-acting nanoformulated ART (nanoART) carriage provides a novel opportunity to simplify drug-dosing regimens. Progress has nonetheless been slowed by cumbersome, but required, pharmacokinetic (PK), pharmacodynamics, and biodistribution testing. To this end, we developed a small magnetite ART (SMART) nanoparticle platform to assess antiretroviral drug tissue biodistribution and PK using magnetic resonance imaging (MRI) scans. Herein, we have taken this technique a significant step further by determining nanoART PK with folic acid (FA) decorated magnetite (ultrasmall superparamagnetic iron oxide [USPIO]) particles and by using SMART particles. FA nanoparticles enhanced the entry and particle retention to the reticuloendothelial system over nondecorated polymers after systemic administration into mice. These data were seen by MRI testing and validated by comparison with SMART particles and direct evaluation of tissue drug levels after nanoART. The development of alendronate (ALN)-coated magnetite thus serves as a rapid initial screen for the ability of targeting ligands to enhance nanoparticle-antiretroviral drug biodistribution, underscoring the value of decorated magnetite particles as a theranostic tool for improved drug delivery.

On the Mechanism of Drug Release from Polysaccharide Hydrogels Cross-Linked with Magnetite Nanoparticles by Applying Alternating Magnetic Fields: the Case of DOXO Delivery

The chemical, biological and physical properties of carboxymethylcellulose (CMC) hydrogels with silanized magnetite (Fe₃O₄) nanoparticles (NPs) as cross-linker were investigated and compared with the analogous hydrogel obtained by using 1,3-diaminopropane (DAP) as cross-linker. The magnetic hydrogel was characterized from the chemical point of view by FT-IR, whereas the morphology of the hydrogel was investigated by FESEM and STEM. The water uptake and rheological measurements reveal how much the swelling and mechanical properties change when CMC is cross-linked with silanized magnetite NPs instead of with DAP. As far as the biological properties, the hybrid hydrogel neither exerts any adverse effect nor any alteration on the cells. The magnetic hydrogels show magnetic hysteresis at 2.5 K as well as at 300 K. Magnetic measurements show that the saturation magnetization, remanent magnetization and coercive field of the NPs are not influenced significantly by the silanization treatment. The magnetic hydrogel was tested as controlled drug delivery system. The release of DOXO from the hydrogel is significantly enhanced by exposing it to an alternating magnetic field. Under our experimental conditions (2 mT and 40 kHz), no temperature increase of the hydrogel was measured, testifying that the mechanism for the enhancement of drug release under the AMF involves the twisting of the polymeric chains. A static magnetic field (0.5 T) does not influence the drug release from the hydrogel, compared with that without magnetic field.

Stable monodisperse nanomagnetic colloidal suspensions: An overview

Magnetic iron oxide nanoparticles (MNPs) have emerged as highly desirable nanomaterials in the context of many research works, due to their extensive industrial applications. However, they are prone to agglomerate on account of the anisotropic dipolar attraction, and therefore misled the particular properties related to single-domain magnetic nanostructures. The surface modification of MNPs is quite challenging for many applications, as it involves surfactant-coating for steric stability, or surface modifications that results in repulsive electrostatic force. Hereby, we focus on the dispersion of MNPs and colloidal stability.

Sticky tubes and magnetic hydrogels co-assembled by a short peptide and melanin-like nanoparticles

The co-assembly of peptide monomers and polydopamine-based nanoparticles leads to the formation of either tubular structures decorated with adhesive particles or magnetic hydrogel.

Electrospun cellulose acetate-garnet nanocomposite magnetic fibers for bioseparations

Cellulose acetate fibers with magnetic properties have recently attracted much attention because of their potential novel applications in biomedicine such as for cell and protein separations, magnetic resonance imaging contrast agents, and magnetic filters. In this work, as synthesized yttrium iron garnet and gadolinium substituted yttrium iron garnet nanoparticles have been used to generate magnetic filter paper. Garnet nanoparticles dispersed in cellulose acetate polymer solutions were electrospun as free-standing nonwoven fiber mats as well as on cellulose filter paper substrates resulting in magnetic filter papers. The magnetic fibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and superconducting quantum interference device (SQUID) magnetic property measurements. The resulting magnetic polymer nanocomposites can be easily picked up by an external magnet from a liquid medium. Fluorescein isothiocyanate (FITC) labeled bovine serum albumin (BSA) was separated from solution by using the magnetic filter paper.

A Facile Approach to Fabrication of Novel Magnetic Hydrogels Crosslinked by Multi-Functional Pomegranate-Like Nanospheres

A facile approach was explored to fabricate a novel magnetic hydrogel using pomegranate-like functional magnetic nanospheres (FMNs) as photoactive crosslinker and polyacrylamide as polymer matrix by photoinitiated free radical polymerization. These novel pomegranate-like FMNs were prepared by embedding Fe3O4 nanoparticles into polystyrene by miniemulsion polymerization. The effect of FMN concentration, acrylamide monomer molar concentration, polymerization time on the magnetic properties, morphology, swelling behaviour, and dynamic mechanical properties of magnetic hydrogels were systematically investigated. Our synthetic route expands the application of these materials in the fields of smart magnetic switches, targeted drug release, biomimetic sensors, and chemical devices.

Synthesis of a novel supermagnetic iron oxide nanocomposite hydrogel based on graft copolymerization of poly((2-dimethylamino)ethyl methacrylate) onto salep for controlled release of drug

In this research, a novel supermagnetic iron oxide nanocomposite hydrogel was prepared using simultaneous in situ formation of iron oxide nanoparticles (IONs) and three-dimensional cross-linked polymer networks based on graft copolymerization of poly((2-dimethylamino)ethyl methacrylate) (PDMA) onto salep (PDMA-g-salep). The prepared ION-PDMA-g-salep hydrogel was systematically characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDAX), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). In addition, the ION-PDMA-g-salep hydrogel exhibits favorable swelling properties that are sensitive to temperature, pH, and external magnetic field (EMF). The drug release behavior of the prepared hydrogel under EMF, different temperatures and pHs was also studied for the evaluation of the release mechanism and determination of diffusion coefficients. Finally, the antibacterial activity and cytotoxicity studies of the prepared hydrogel were examined. These results suggested that the ION-PDMA-g-salep hydrogel could be a promising candidate for biological dressing applications.

One-pot synthesis of biocompatible superparamagnetic iron oxide nanoparticles/hydrogel based on salep: characterization and drug delivery

This work describes synthesis of biocompatible magnetic iron oxide nanoparticles/hydrogel based on salep (MION-salep hydrogel) by a facile one-pot strategy. The prepared sample was characterized by techniques like scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDAX), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), and vibrating sample magnetometer (VSM). The obtained MION had an 8 nm diameter with a narrow size distribution and was superparamagnetic with large saturation magnetization at room temperature. The most attractive feature of the obtained sample was its swelling properties under external magnetic field (EMF), different temperatures, and pHs. Moreover, MION-salep hydrogel showed ability to deferasirox release at pH=7 with non-Fickian diffusion mechanism. An in vitro cytotoxicity study implied that the as-synthesized sample is nontoxic.

Biohydrogels with magnetic nanoparticles as crosslinker: characteristics and potential use for controlled antitumor drug-delivery

Hybrid magnetic hydrogels are of interest for applications in biomedical science as controlled drug-delivery systems. We have developed a strategy to obtain novel hybrid hydrogels with magnetic nanoparticles (NPs) of CoFe(2)O(3) and Fe(3)O(4) as crosslinker agents of carboxymethylcellulose (CMC) or hyaluronic acid (HYAL) polymers and we have tested these systems for controlled doxorubicin release. The magnetic NPs are functionalized with (3-aminopropyl)trimethoxysilane (APTMS) in order to introduce amino groups on the surface. The amino coating is determined and quantified by standard Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy methods, and by cyclic voltammetry, a novel approach that permits us to look at the solution properties of the functionalized NPs. The gel formation involves the creation of an amide bond between the carboxylic groups of CMC or HYAL and the amine groups of functionalized NPs, which work as crosslinking agents of the polymer chains. The hybrid hydrogels are chemically and morphologically characterized. The rheological and the water uptake properties of the hydrogels are also investigated. Under the application of an alternating magnetic field, the CMC-HYAL hybrid hydrogel previously loaded with doxorubicin shows a drug release greater than that showed by the CMC-HYAL hydrogel crosslinked with 1,3-diaminopropane. In conclusion, the presence of magnetic NPs makes the synthesized hybrid hydrogels suitable for application as a drug-delivery system by means of alternating magnetic fields.