Cross-linked Poly Ethylene Glycol Research Articles

Nanoscale distribution of CD20 on B‐cell lymphoma tumour cells and its potential role in the clinical efficacy of rituximab

Rituximab is an exciting monoclonal antibody drug approved for treating B-cell lymphomas and its target is the CD20 antigen which is expressed on the surface of B cells. In recent years, the variable efficacies of rituximab among different lymphoma patients have become an important clinical issue and urgently need to be solved for further development of antibodies with enhanced efficacies. In this work, atomic force microscopy (AFM) was used to investigate the nanoscale distribution of CD20 on the surface of tumour B cells from lymphoma patients to examine its potential role in the clinical therapeutic effects of rituximab. By performing ROR1 fluorescence labelling (ROR1 is a specific tumour cell surface marker) on the bone marrow cells prepared from B-cell lymphoma patients, the tumour B cells were recognized, and then AFM tips carrying rituximabs via polyethylene glycol crosslinkers were moved to the tumour cells to probe the specific CD20-rituximab interactions. By applying AFM single-molecule force spectroscopy (SMFS) at the local areas (500×500 nm²) on the surface of tumour B cells, the nanoscale distributions of CD20 on the surface of tumour B cells were mapped, visually showing that CD20 distributed heterogeneously on the cell surface. Bone marrow cell samples from three clinical B-cell lymphoma cases were collected to analyze the binding affinity and nanoscale distribution of CD20 on tumour cells. The experimental results showed that CD20 distribution on tumour cells were to some extent related to the clinical therapeutic outcomes while the CD20-rituximab binding forces did not have distinct effects to the clinical outcomes. These results can provide novel insights in understanding the rituximab's clinical efficacies from the nanoscale distribution of CD20 on the tumour cells at single-cell and single-molecule levels.

A shape memory hydrogel induced by the interactions between metal ions and phosphate.

A novel ferric-phosphate induced shape memory (SM) hydrogel is prepared by the one-step copolymerization of isopropenyl phosphonic acid (IPPA) and acrylamide (AM) in the presence of a crosslinker polyethylene glycol diacrylate (PEGDA). Different from the traditional SM hydrogels, our SM hydrogel can be processed into various shapes as needed and recovers to its original form in ‘multiconditions’ such as in the presence of a reducing agent or in the presence of a competitive complexing agent. This unique feature is attributed to the fact that the oxidized ferric ions show a high complexation ability with phosphate groups of IPPA, which acts as a physical crosslinker to form the secondary networks within the hydrogels to induce the shape memory effect. The memory behavior was totally reversible, owing to Fe3+ that can be reduced to Fe2+ and extracted by the complexing agent. Particularly, the SM hydrogels exhibit controllable and good mechanical characteristics by introduction of the ferric ions, i.e., the elastic modulus can increase from 2 kPa to 70 kPa dramatically. Learning from biological systems, phosphate-metal ion based hydrogels could become an attractive candidate for various biomedical and environmental applications.

A novel pH-sensitive interferon-β (INF-β) oral delivery system for application in multiple sclerosis

pH-sensitive microparticles were prepared using trimethyl-chitosan (TMC), poly(ethylene glycol)dimethacrylate (PEGDMA) and methacrylic acid (MAA) by free radical suspension polymerization, for the oral delivery of interferon-β (INF-β). The microparticles were subsequently compressed into a suitable oral tablet formulation. A Box-Behnken experimental design was employed for generating a series of formulations with varying concentrations of TMC (0.05-0.5 g/100 mL) and percentage crosslinker (polyethylene glycol diacrylate) (3-8%, w/w of monomers), for establishment of an optimized TMC-PEGDMA-MAA copolymeric microparticles. For pragmatism, insulin was initially employed as the model peptide for undertaking the preliminary experimentation and the optimized formulation was subsequently evaluated using INF-β. The prepared copolymeric microparticulate system was characterized for its morphological, porositometric and mucoadhesive properties. The optimized microparticles with 0.5 g/100 mL TMC and 3% crosslinker had an INF-β loading efficiency of 53.25%. The in vitro release of INF-β was recorded at 74% and 3% in intestinal (pH 6.8) and gastric (pH 1.2) pH from the oral tablet formulation, respectively. The tablet was further evaluated for plasma concentration of INF-β in the New Zealand White rabbit, and compared to a known subcutaneous formulation. The system showed an astounding effective release profile over 24h with higher INF-β plasma concentrations compared with the subcutaneous injection formulation.

Preparation and physical properties of a macroscopically aligned lyotropic hexagonal phase templated hydrogel

Lyotropic liquid crystal (LLC) materials, such as lyotropic liquid single crystal hydrogels (LLSCHs) and LLC templated hydrogels, have the potential for a wide range of applications from nanomaterials to drug delivery. Most of the applications are dependent on transport processes through the gels. While powder distribution LLC hydrogels and elastomers have been shown to be alignable by uniaxial stress/strain, LLSCH that are macroscopically aligned can be made by photopolymerisation after alignment of suitable polymerisable surfactants. Cross-linked polyethylene glycol diacrylate (PEG-DA) hydrogels, have previously been templated using powder distribution LLC phases of non-polymerisable surfactants. In this work, a macroscopically aligned LLC hexagonal phase templated PEG-DA hydrogel was made. The alignment was monitored with 2H NMR quadrupole splitting which showed that the hydrogel retained the macroscopic alignment after photopolymerisation. The effects of compression/deswelling were recorded using optical and polarised optical microscopy (POM). However, the focus of this work was on studying the self-diffusion of water in the hydrogel, which is pertinent not only for the typical applications of these materials but for potentially new applications. Pulsed gradient spin-echo nuclear magnetic resonance (PGSE NMR) provides a way of investigating the self-diffusion easily and non-invasively. Interestingly the measured self-diffusion of water, at least for the sample in this study, was relatively independent of the diffusion time used (i.e., 70ms to 3s).

Pro-angiogenic and Anti-inflammatory Regulation by Functional Peptides Loaded in Polymeric Implants for Soft Tissue Regeneration

Inflammation and angiogenesis are inevitable in vivo responses to biomaterial implants. Continuous progress has been made in biomaterial design to improve tissue interactions with an implant by either reducing inflammation or promoting angiogenesis. However, it has become increasingly clear that the physiological processes of inflammation and angiogenesis are interconnected through various molecular mechanisms. Hence, there is an unmet need for engineering functional tissues by simultaneous activation of pro-angiogenic and anti-inflammatory responses to biomaterial implants. In this work, the modulus and fibrinogen adsorption of porous scaffolds were tuned to meet the requirements (i.e., ~100 kPa and ~10 nm, respectively), for soft tissue regeneration by employing tyrosine-derived combinatorial polymers with polyethylene glycol crosslinkers. Two types of functional peptides (i.e., pro-angiogenic laminin-derived C16 and anti-inflammatory thymosin β4-derived Ac-SDKP) were loaded in porous scaffolds through collagen gel embedding so that peptides were released in a controlled fashion, mimicking degradation of the extracellular matrix. The results from (1) in vitro coculture of human umbilical vein endothelial cells and human blood-derived macrophages and (2) in vivo subcutaneous implantation revealed the directly proportional relationship between angiogenic activities (i.e., tubulogenesis and perfusion capacity) and inflammatory activities (i.e., phagocytosis and F4/80 expression) upon treatment with either type of peptide. Interestingly, cotreatment with both types of peptides upregulated the angiogenic responses, while downregulating the inflammatory responses. Also, anti-inflammatory Ac-SDKP peptides reduced production of pro-inflammatory cytokines (i.e., interleukin [IL]-1β, IL-6, IL-8, and tumor necrosis factor alpha) even when treated in combination with pro-angiogenic C16 peptides. In addition to independent regulation of angiogenesis and inflammation, this study suggests a promising approach to improve soft tissue regeneration (e.g., blood vessel and heart muscle) when inflammatory diseases (e.g., ischemic tissue fibrosis and atherosclerosis) limit the regeneration process.

High-flux and fouling-resistant membranes for brackish water desalination

Novel high-flux and fouling-resistant reverse osmosis membrane were synthesized and characterized under brackish water desalination conditions using 2000ppm NaCl solution at 225psi (1.55MPa) and 25°C. The o-aminobenzoic acid-triethylamine salt was added into m-phenylenediamine (MPD) solution to react with trimesoyl chloride (TMC) during the interfacial polymerization between MPD and TMC. The membrane synthesis conditions including MPD concentration, TMC concentration, and interfacial polymerization time were optimized. The membrane synthesized under the optimal conditions was post-treated with aqueous solutions containing glycerol, sodium lauryl sulfate, and camphorsulfonic acid-triethylamine salt to further increase the water flux. The resulting membrane showed a flux of 2.22m3/m2/day (54.4gallons/ft2/day (gfd)) and a salt rejection of 98.6%. The fouling-resistant property of the synthesized membrane was enhanced by physically coating a cross-linked polyethylene glycol (PEG-200) layer on top of the thin film. The membrane coated with 10wt% cross-linked PEG demonstrated a very high flux of 2.46m3/m2/day (60.4gfd) and outperformed the state-of-the-art commercial membrane. Using dodecyltrimethylammonium bromide, a cationic foulant, and tannic acid, an anionic foulant, as model foulants, the coated membrane exhibited much reduced flux decline. The surface morphologies of the modified and unmodified membranes were analyzed using scanning electron microscopy and atomic force microscopy. The results showed a smoother membrane surface by coating the PEG layer.

RGDS-functionalized polyethylene glycol hydrogel-coated magnetic iron oxide nanoparticles enhance specific intracellular uptake by HeLa cells

The objective of this study was to develop thin, biocompatible, and biofunctional hydrogel-coated small-sized nanoparticles that exhibit favorable stability, viability, and specific cellular uptake. This article reports the coating of magnetic iron oxide nanoparticles (MIONPs) with covalently cross-linked biofunctional polyethylene glycol (PEG) hydrogel. Silanized MIONPs were derivatized with eosin Y, and the covalently cross-linked biofunctional PEG hydrogel coating was achieved via surface-initiated photopolymerization of PEG diacrylate in aqueous solution. The thickness of the PEG hydrogel coating, between 23 and 126 nm, was tuned with laser exposure time. PEG hydrogel-coated MIONPs were further functionalized with the fibronectin-derived arginine-glycine-aspartic acid-serine (RGDS) sequence, in order to achieve a biofunctional PEG hydrogel layer around the nanoparticles. RGDS-bound PEG hydrogel-coated MIONPs showed a 17-fold higher uptake by the human cervical cancer HeLa cell line than that of amine-coated MIONPs. This novel method allows for the coating of MIONPs with nano-thin biofunctional hydrogel layers that may prevent undesirable cell and protein adhesion and may allow for cellular uptake in target tissues in a specific manner. These findings indicate that the further biofunctional PEG hydrogel coating of MIONPs is a promising platform for enhanced specific cell targeting in biomedical imaging and cancer therapy.

Cross-linked acrylic hydrogel for the controlled delivery of hydrophobic drugs in cancer therapy

Objective:To investigate cross-linked hydrogels prepared via inverse emulsion polymerization to entrap poorly aqueous soluble drugs. Polyethylene glycol cross-linked acrylic polymers were synthesized and the loading and release of curcumin, a model hydrophobic drug, was investigated.Methods:Physicochemical characteristics of hydrogels were studied with 13C nuclear magnetic resonance, Fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, differential scanning calorimetry, and swelling. Polymerization of the acrylic acid with cross-linked polyethylene glycol diacrylate was characterized with 13C nuclear magnetic resonance imaging and Fourier transform infrared spectroscopy.Results:The in vitro release rate of curcumin showed that there was a sustained release from the hydrogel with increased cross-linking; the release rate depended on the pH of the releasing medium. Intracellular and cytotoxicity studies were carried out in human cervical cancer cell lines.Conclusion:The results suggest cross-linked acrylic polymers can be used as efficient vectors for pH-sensitive, controlled delivery of hydrophobic drugs.

An AFM-FET Biosensor for Proteomic Screening

 Abstract—An atomic force microscope (AFM) and a field effect transistor (FET) were integrated into one functioning novel biosensor to probe single molecular interactions between biomolecules, such as proteins and ligands. The interactions between avidin-biotin complexes were studied using the AFM-FET biosensor. Biotin molecules were attached to the AFM cantilever via flexible polyethylene glycol cross-linkers, and avidin molecules were bound to the palladium gate surface of the FET via the cross-linker molecules, cystamine and glutaraldehyde. The force of the AFM and the FET current between the drain and source was measured as a function of distance when the biotin molecules approached and retracted from the avidin molecules. The measurement data showed that the FET current changed abruptly when binding and unbinding events occurred between the two molecules. This change in the current was generated from the corresponding electric potential, which was related to the magnitude of unbinding force during the binding and unbinding events. The relationship suggests that the AFM-FET biosensor can provide potential voltages generated during the biding and unbinding events. This additional information on molecular interactions at the single molecular level could potentially be used as a quantitative and efficient method for detecting single molecular interactions. The novel AFM-FET biosensor is potentially advantageous over current drug screening methods based on microfluidics, due to the AFM-FET ability to record single interactions more quickly and accurately.

Determination of hydrate inhibitor in crude oil by nanoextraction–gas chromatography

This work focused on the quantitation of methanol as a hydrate inhibitor in crude oil. The novelty is nanoextraction of a polar compound from a complex non-polar matrix and selection of the proper fiber with maximum selectivity, loading percent, and lifetime. This approach not only does not require specific instrumentation, such as multiple columns and selective detectors, but also has eliminated the use of organic solvent and avoids the insertion of water inside the GC columns. The objective is optimization of extraction conditions, GC adjustments, and data processing. Experiments were conducted on the real sample of Iranian offshore crude oil by a carboxen/PDMS fiber via GC equipped with a cross-linked polyethylene glycol column and flame ionization detector. The results revealed that this fiber adsorbed the alcohols among other light non-polar compounds of crude oil. Moreover, the interference effects of ethanol were solved by proper selection of the thermal program. The LOD, LOQ, and linear range of this approach were determined to be 3.9, 12.9, and 14-229 ppm for methanol, respectively. Using the standard calibration and the standard addition methods, the relative errors of 1.6-7.2 and 5.3-14.0% were determined.

Pilot plant performance of rubbery polymeric membranes for carbon dioxide separation from syngas

Pre-combustion carbon capture separates carbon dioxide from syngas before combustion. Rubbery polymeric membranes offer the ability to separate carbon dioxide from syngas, and in particular hydrogen, with reasonable selectivity. Here, the gas separation performance of three rubbery polymeric membranes, poly dimethyl siloxane (PDMS), cross-linked polyethylene glycol (PEG) and poly (ether-b-amide) (PEBAX 2533), are reported upon exposure to real unshifted syngas, as part of the CO2CRC Mulgrave capture project. At low temperatures, all three membranes were able to separate CO 2 from syngas; however competitive sorption by other syngas components significantly altered their performance relative to reported laboratory results. For PDMS, under syngas conditions CO 2 permeability was reduced compared to the pure gas permeability, but CO 2/H 2 and CO 2/N 2 selectivity were improved in the presence of syngas. This resulted in good CO 2 separation performance for this membrane. However over 24 h of exposure the performance decreased somewhat. In contrast, both PEG and PEBAX membranes demonstrated poor CO 2 separation performance upon exposure to syngas. In particular, low CO 2/H 2 selectivities where observed, indicating that both membranes upon exposure to syngas had poor selective ability.

SPME–GC determination of methanol as a hydrate inhibitor in crude oil

This work focused on the quantitation of methanol as a hydrate inhibitor in the crude oil. The novelty is microextraction of a polar compound from a complex non-polar matrix and selection of proper fiber with maximum selectivity, loading percent, and lifetime. This approach not only does not require specific instrumentation, such as multiple columns, and selective detectors, but also has eliminated the use of organic solvent and avoids the insertion of water inside the GC columns. The objective is optimization of extraction conditions, GC adjustments and data processing. Experiments were conducted on the real sample of Iranian offshore crude oil by a carboxen/PDMS fiber via a GC equipped with a cross-linked polyethylene glycol column and FID. The results revealed that this fiber adsorbed the alcohols among other light non-polar compounds of crude oil. Moreover, the interference effects of ethanol were solved by proper selection of thermal program. The LOD, LOQ and linear range of this approach were determined to be 3.9, 12.9 and 14–229mgL−1 for methanol, respectively. Moreover, the sensitivity was 30 area-counts per mgL−1. Using the standard calibration and the standard addition methods, the relative errors of 1.6–7.2 and 5.3–14.0% were determined, respectively.

Synthesis of solid–solid phase change material for thermal energy storage by crosslinking of polyethylene glycol with poly (glycidyl methacrylate)

Abstract Polyethylene glycol (PEG10000)/poly (glycidyl methacrylate) (PGMA) crosslinked copolymer as a novel solid–solid phase change material (SSPCM) was successfully synthesized through the ring-opening crosslinking reaction of end-carboxyl groups in carboxyl polyethylene glycol (CPEG) and epoxy groups in PGMA. Fourier transform infrared spectroscopy (FT-IR), polarizing optical microscopy (POM), wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and thermogravimetry (TG) were employed to study the chemical structure, crystalline properties, phase transition behaviors and the thermal stability of the copolymer, respectively. The results from WAXD patterns and POM images show that the crystalline form of the copolymer is similar with that of pure PEG, and the PEG soft segment phase transition between crystalline and amorphous states results in heat storage and release of the copolymer. Due to the crosslinking network restricted the free movement of the soft segments, at temperature above the PEG phase melting transition, the copolymer was still solid. The DSC results indicate that the copolymer imparts balanced and reversible phase change behaviors at the temperature range of 25–60 °C, and it has high latent heat storage capacity of more than 70 J/g. The TG results suggest that the copolymer had a much broader applicable temperature range compared with pure PEG.

Effects of branched polyethylene glycol derivative crosslinking on the structure and conformation stability of bovine tendon type I collagen

Objective The triple helix of collagen is the basis of its biological function, such as cell adhesion and tissue remodeling. Crosslinking of collagen with chemical agent will improve the biomechanical properties. However, the effects of differernt crosslinking agents on the structure and conformation stability of type Ⅰ collagen are rarely investigated. Methods The branched polyethylene glycol ( PEG)derivative ( MW 12 kD) was used as crosslinking agent, and allowed to react with bovine achilles' s tendon type Ⅰ collagen modified by succinimidylacetylthioacetate (SATA). The ability of resistance of crosslinked collagen to enzymatic degradation was investigated by measuring the release of hydroxyproline, and differential scanning calorimeter ( DSC ) was taken to determine the thermal denaturation temperature. The effect of PEG on the riple helix of collagen was studied by circular dichroism ( CD) . Results The resistance ability of PEG crosslinked collagen was strongly enhanced when compared with that of control group ( P ＜0. 05 ) , and the thermal denaturation temperature was also significantly rised. CD demonstrated that PEG crosslinking did not result in the destruction of the triple helix conformation of type Ⅰ collagen. Conclusion Branched PEG derivative used in this study is a promising polymer crosslinking agent that may be utilized in the modification of type Ⅰ collagen. Key words: Type Ⅰ collagen; Polyethylene glycol; Thermal denaturation temperature

Improvement in poly(lactic acid) fabric performance via hydrophilic coating

The effects of a hydrophilic coating on poly(lactic acid) (PLA) fabric using polyethylene glycol–dimethyloldihydroxyethyleneurea (PEG–DMDHEU) were studied to obtain highly cross-linked polyethylene glycol (PEG) with acceptable fastness properties owing to the possibility of fixation PEG on the fibres surface at lower temperature than melting point of PLA fibres. PEG as a Phase Change Materials (PCMs) imparts thermal adaptability, which is so important for the comfort of textiles, to the substrate. While there is a good adhesion between the fibre and the PEG polymer for cotton and polyester fibres, polymer adhesion to PLA fibres and its effects on PLA fabrics have never been studied. The effect of hydrophilic coating on the PLA fabric was studied in comparison to polyethylene terephthalate (PET) fabric by measuring the thermal regulating effect, antistatic, air permeability, and mechanical properties. The results exhibit the possibility of multipurpose finishing on both fabrics samples leading to permanent thermal regulating effect and durable antistatic finish.

Core Cross-Linked Polyethylene Glycol Oleate Micelles as Novel Drug Carriers

Polyethylene Glycol Oleate was synthesized by esterification of polyethylene glycol and Oil acid using DMAP as a catalyst. The double bonds of the product in the core of micelles were cross-linked by the initiation of (NH4)2S2O8 during the micelles formed. Applications of the noncross-linked and cross-linked polyethylene glycol oleate in drug delivery were studied, which indicates that drug efficiency decreased after micelles were core cross-linked, but release rate of MTX from core cross-linked micelles seems slower than that from noncross-linked micelles.

Tailoring the mechanical performance of highly permeable macroporous polymers synthesized via Pickering emulsion templating

Highly interconnected macroporous polymers can be produced by the polymerization of high internal phase emulsions (HIPEs) with a dispersed phase exceeding 74 vol%. Until recently, it was thought that poly(merized)HIPEs with a maximum reported gas permeability of 0.46 D could only be produced by the polymerization of surfactant stabilized HIPE templates. However, highly permeable macroporous polymers with a gas permeability of up to 2.6 D were successfully prepared by adding small amounts of a non-ionic surfactant to pre-made Pickering emulsion templates; poor mechanical properties (crush strengths of ≤2.2 MPa) however limit the applicability of these materials. The mechanical properties were improved by altering the composition of the emulsion template. This involved using the flexible crosslinker polyethylene glycol dimethacrylate (PEGDMA), alongside other organic additives like divinylbenzene (DVB) and squalene in the organic phase. We also increased the material density by using medium internal phase emulsion (MIPE) templates and increased the surfactant concentration added to the pre-made Pickering-MIPEs. The resulting materials were characterized in terms of pore structure, gas permeability and mechanical performance. SEM images revealed pores of up to 1700 μm in diameter and interconnecting pore throats of up to 100 μm in diameter. The highest gas permeability and crush strength achieved were 0.92 ± 0.09 D and 5.6 ± 0.1 MPa, respectively, for a macroporous polymer synthesized from a Pickering-MIPE containing 50 : 40 : 10 (by volume) styrene, PEGDMA and DVB respectively, in the organic phase, to which 10 vol% Hypermer 2296 was added.

Robust MeO 2MA/vinyl-4,6-diamino-1,3,5-triazine copolymer hydrogels-mediated reverse gene transfection and thermo-induced cell detachment

We have fabricated a robust temperature sensitive hydrogel by photoinitiated copolymerization of 2-(2-methoxyethoxy)ethyl methacrylate (MeO 2MA), 2-vinyl-4,6-diamino-1,3,5-triazine (VDT) and crosslinker polyethylene glycol diacrylate (PEGDA). It was shown that self-hydrogen bondings of VDT moieties in the bulk considerably strengthened the mechanical properties of gels, which was dependent on the weight ratio of MeO 2/VDT and the initial monomer concentration; the VDT motifs on the surface could efficiently bind DNA for reverse gene transfection. On this soft-wet platform, gene expression lasted 7 days and the re-treated gels could be reused for new cycle of transfection. The gene modified cells could be detached by thermo-triggered switchable surface hydrophilicity of PMEO 2MA in hydrogel. MTT assay showed low cytotoxicity of hydrogels. The results suggested that this type of mechanically strong H-bonded and thermoresponsive hydrogels hold a great potential as an integrated functional soft-wet platform for the unharmful harvest of gene modified seed cells for tissue engineering or as implantable scaffold for gene therapy and regenerative medicine applications.

Improvement in fastness properties of phase-change material applied on surface modified wool fabrics

The comfort of textiles is important and one area under evaluation is the development and application of Phase Change Materials, PCMs, in order to impart thermal adaptability. PCMs research for textiles has also focused on the use of polyethylene glycol (PEG). While there is a good adhesion between fibre and PEG polymer for cotton and polyester fibres, polymer adhesion to wool fibres appears poor and loosely bound within the yarn and had dislodged and crumbled. Therefore in this paper, the effect of changing the wool fibre surface energy and surface charge, shrinkproofing, on performance properties of thermally adaptable wool fabrics were studied. Untreated, gaseous fluorinated, as well as Chlorine-Hercosett treated 100 % wool fabrics have been evaluated to obtain highly cross-linked PEG with acceptable fastness properties. The surface interface was effectively probed by XPS & ToF-SIMS and characterised the loss of surface lipids, the nature of the fibre oxidation and deposition of Hercosett polymer on the wool fibre. The results indicate the necessity of having high surface energy in order to obtain appropriate adhesion and binding higher amount of solid polymer to wool fibres which results in superior thermal activity, better durability, and enhancement in felting performance.

Superparamagnetic Iron Oxide Nanoparticles with Rigid Cross-linked Polyethylene Glycol Fumarate Coating for Application in Imaging and Drug Delivery

Superparamagnetic iron oxide nanoparticles with proper surface coatings are increasingly being evaluated for clinical applications such as hyperthermia, drug delivery, magnetic resonance imaging, transfection, and cell/protein separation. To enhance the applicability of magnetic nanoparticles, two main problems must be overcome. First, as the drug coats the particle surface, a significant portion of it is quickly released upon injection (burst effect). Therefore, only small amounts of the drug reach the specific site after, for example, magnetic drug targeting. Second, once the surface-derivatized nanoparticles are inside the cells, the coating is likely digested, leaving the bare particles exposed to other cellular components and organelles, thereby potentially influencing the overall integrity of the cells. To overcome these two shortcomings, iron oxide nanoparticles with cross-linked poly (ethylene glycol)-co-fumarate (PEGF) coating were synthesized. The obtained material was highly stable and easy to ...