Iron/iron oxide core/shell nanoparticles for magnetic targeting MRI and near-infrared photothermal therapy

The development of photothermal agents (PTAs) with good stability, low toxicity, highly targeting ability and photothermal conversion efficiency is an essential pre-requisite to near-infrared photothermal therapy (PTT) in vivo. Herein, we report the readily available PEGylated Fe@Fe3O4 NPs, which possess triple functional properties in one entity - targeting, PTT, and imaging. Compared to Au nanorods, they exhibit comparable photothermal conversion efficiency (∼20%), and much higher photothermal stability. They also show a high magnetization value and transverse relaxivity (∼156 mm(-1) s(-1)), which should be applied for magnetic targeting MRI. With the Nd-Fe-B magnet (0.5 T) beside the tumour for 12 h on the xenograft HeLa tumour model, PEGylated Fe@Fe3O4 NPs exhibit an obvious accumulation. In tumour, the intensity of MRI signal is ∼ three folds and the increased temperature is ∼ two times than those without magnetic targeting, indicating the good magnetic targeting ability. Notably, the intrinsic high photothermal conversion efficiency and selective magnetic targeting effect of the NPs in tumour play synergistically in highly efficient ablation of cancer cells in vitro and in vivo.

Dual pH and temperature stimuli-responsive magnetic nanohydrogels for thermo-chemotherapy

Dual stimuli pH and temperature-responsive nanohydrogels based on poly(N-isopropylacrylamide)-chitosan have been synthesized. Fe3O4 magnetic nanoparticles (NPs) (-12 nm) have been incorporated into hydrogels to achieve temperature optimized magnetic nanohydrogel (MNHG) for magnetic hyperthermia with lower critical solution temperature, LCST > 42 degrees C. The composite was further investigated for its potential application in drug delivery and in vitro cancer cell cytotoxicity. Water-bath assisted drug release studies were carried out using anti-cancer drug doxorubicin (DOX) in acetate buffer medium (pH - 4.6) to mimic tumor cell environment which is slightly acidic in nature. The pH and temperature responsiveness of the system was demonstrated by DOX release under different conditions. The released amount of DOX was found to be nearly 4 microg/mg above hyperthermia temperature (-42 degrees C) as opposed to only 1.9 microg/mg of MNHG at physiological temperature (37 degrees C) under acidic environment (pH - 4.6). Further, AC magnetic field (AMF) induced heating of NPs entrapped inside hydrogels showed appreciable reduction of cell population in human breast (MCF-7) and cervical carcinoma (HeLa) cell lines for given duration of field exposures. Quantitatively, death percentages of HeLa cells were nearly 35 and 45% while for MCF-7, these were 20 and 70% when exposed to AMF for 10 and 30 min, respectively. Further the cell killing efficacy of MNHG loaded with DOX was assessed under AMF using HeLa cell lines. The AMF induced heat triggered DOX release from the MNHG which enhances the cell death up to 85% due to combined effect of thermo-chemotherapeutics. The present system with both pH and temperature responsivity serves as a promising candidate for a combination therapy.

The inhibitory and apoptotic effects of docetaxel-loaded mesoporous magnetic colloidal nanocrystal clusters on bladder cancer T24 cells in vitro

Mesoporous magnetic colloidal nanocrystal clusters (MCNCs) are featured with high magnetization, adequate surface area, excellent colloidal stability, good biocompatibility, and acid degradability. It is thus highly anticipated that MCNCs can serve as vehicles for target drug delivery. Herein, the mesoporous MCNCs stabilized by poly(gamma-glutamic acid) (PGA) were fabricated by the modified solvothermal route, showing a high specific surface area (126.4 m2/g), strong magnetic response (63 emu/g) and appropriate mesoporosity including a large pore volume (0.27 cm3/g) and accessible pore size (8.1 nm). Docetaxel (DOC) was then loaded in the resultant MCNCs using the nanoprecipitation method, and a high drug loading capacity was achieved up to 24 wt%. The chemotherapeutic effect and mechanism of DOC-MCNC conjugates in bladder cancer was evaluated in vitro. A series of analyses for cell uptake, cell viability, cell cycle, cell apoptosis and some cell proteins were performed by transmission electron microscopy, MTT assay, flow cytometry, cell nuclei staining, Annexin V staining assay, western blot assay and caspase-3 activity assay, respectively. The results demonstrated that DOC-MCNC conjugates enhanced the inhibitory effect by hampering mitoschisis and increased the apoptotic effect by changing the expression of apoptosis-related proteins in T24 cells, substantially proving their remarkable efficiency in treatment of bladder cancer.

Bench-to-bedside translation of magnetic nanoparticles

Magnetic nanoparticles (MNPs) are a new and promising addition to the spectrum of biomedicines. Their promise revolves around the broad versatility and biocompatibility of the MNPs and their unique physicochemical properties. Guided by applied external magnetic fields, MNPs represent a cutting-edge tool designed to improve diagnosis and therapy of a broad range of inflammatory, infectious, genetic and degenerative diseases. Magnetic hyperthermia, targeted drug and gene delivery, cell tracking, protein bioseparation and tissue engineering are but a few applications being developed for MNPs. MNPs toxicities linked to shape, size and surface chemistry are real and must be addressed before clinical use is realized. This article presents both the promise and perils of this new nanotechnology, with an eye towards opportunity in translational medical science.

Magnetite nanostructures functionalized with cytostatic drugs exhibit great anti-tumoral properties without application of high amplitude alternating magnetic fields

Here, we report the synthesis, characterization and the impact of magnetite nanoparticles functionalized with cytostatic drugs, epirubicin (Epi) and fludarabine (Flu) (Fe3O4@Epi, Fe3O4@Flu) prepared by chemical co-precipitation method on tumoral cells in vitro. The average diameter of the resulted particles was about 4 nm for both Fe3O4@Epi and for Fe3O4@Flu. These bioactive nanostructured materials proved to significantly enhance the antitumor effect of tested cytostatic drugs in vitro. The most significant result was obtained in the case of Epi, where the tested magnetite nanostructured material enhanced the cytotoxic effect of this drug with more than 50%.

The role of functionalized magnetic iron oxide nanoparticles in the central nervous system injury and repair: new potentials for neuroprotection with Cerebrolysin therapy

Functionalized Magnetic Iron Oxide Nanoparticles (FMIONPs) are being explored for the development of various biomedical applications, e.g., cancer chemotherapy and/or several other radiological or diagnostic purposes. However, the effects of these NPs per se on the central nervous system (CNS) injury or repair are not well known. This review deals with different aspects of FMIONPs in relation to brain function based on the current literature as well as our own investigation in animal models of CNS injuries. It appears that FMIONPs are innocuous when administered intravenously within the CNS under normal conditions. However, abnormal reactions to FMIONPs in the brain or spinal cord could be seen if they are combined with CNS injuries e.g., hyperthermia or traumatic insults to the brain or spinal cord. Thus, administration of FMIONPs in vivo following whole body hyperthermia (WBH) or a focal spinal cord injury (SCI) exacerbates cellular damage. Since FMIONPs could help in diagnostic purposes or enhance the biological effects of radiotherapy/chemotherapy it is likely that these NPs may have some adverse reaction as well under disease condition. Thus, under such situation, adjuvant therapy e.g., Cerebrolysin (Ever NeuroPharma, Austria), a suitable combination of several neurotrophic factors and active peptide fragments are the need of the hour to contain such cellular damages caused by the FMIONPs in vivo. Our observations show that co-administration of Cerebrolysin prevents the FMIONPs induced pathologies associated with CNS injuries. These observations support the idea that FMIONPs are safe for the CNS in disease conditions when co-administered with cerebrolysin. This indicates that cerebrolysin could be used as an adjunct therapy to prevent cellular damages in disease conditions where the use of FMIONPs is required for better efficacy e.g., cancer treatment.

Alzheimer's disease: pathophysiology and applications of magnetic nanoparticles as MRI theranostic agents

Alzheimer's disease (AD) is the most common form of dementia. During the recent decade, nanotechnology has been widely considered, as a promising tool, for theranosis (diagnosis and therapy) of AD. Here we first discuss pathophysiology and characteristics of AD with a focus on the amyloid cascade hypothesis. Then magnetic nanoparticles (MNPs) and recent works on their applications in AD, focusing on the superparamagnetic iron oxide nanoparticles (SPIONs), are reviewed. Furthermore, the amyloid-nanoparticle interaction is highlighted, with the scope to be highly considered by the scientists aiming for diagnostics and/or treatment of AD employing nanoparticles. Furthermore, recent findings on the "ignored" parameters (e.g., effect of protein "corona" at the surface of nanoparticles on amyloid-β (Aβ) fibrillation process) are discussed.

Multifunctional nanoplatforms for targeted multidrug-resistant-bacteria theranostic applications

The emergence of multidrug-resistant-bacteria (MDRB) infection poses a major burden to modern healthcare. Early detection in the bloodstream and a new strategy development for MDRB infection treatment without antibiotics are clinically significant to save millions of lives every year. To tackle the MDRB challenge, the current manuscript reports the design of "multifunctional nanoplatforms" consisting of a magnetic core-plasmonic shell nanoparticle, a methylene blue-bound aptamer, and an MDRB Salmonella DT104 specific antibody. The reported "multifunctional nanoplatform" is capable of targeted separation from a blood sample and sensing and multimodal therapeutic killing of MDRB. Experimental data using an MDRB-infected whole-blood sample show that nanoplatforms can be used for selective magnetic separation and fluorescence imaging. In vitro light-triggered photodestruction of MDRB, using combined photodynamic and photothermal treatment, shows that the multimodal treatment regime can enhance MDRB killing significantly. We discussed the possible mechanisms on combined synergistic therapy for killing MDRB. The "multifunctional nanoplatform" reported in this manuscript has great potential for the imaging and combined therapy of MDRB in clinical settings.

Magnetically triggered dual functional nanoparticles for resistance-free apoptotic hyperthermia

Overcoming resistance: Heat-treated cancer cells possess a protective mechanism for resistance and survival. Resistance-free apoptosis-inducing magnetic nanoparticles (RAINs) successfully promote hyperthermic apoptosis, obstructing cell survival by triggering two functional units of heat generation and the release of geldanamycin (GM) for heat shock protein (Hsp) inhibition under an alternating magnetic field (AMF).

Magnetic nanoparticles: surface effects and properties related to biomedicine applications

Due to finite size effects, such as the high surface-to-volume ratio and different crystal structures, magnetic nanoparticles are found to exhibit interesting and considerably different magnetic properties than those found in their corresponding bulk materials. These nanoparticles can be synthesized in several ways (e.g., chemical and physical) with controllable sizes enabling their comparison to biological organisms from cells (10–100 μm), viruses, genes, down to proteins (3–50 nm). The optimization of the nanoparticles’ size, size distribution, agglomeration, coating, and shapes along with their unique magnetic properties prompted the application of nanoparticles of this type in diverse fields. Biomedicine is one of these fields where intensive research is currently being conducted. In this review, we will discuss the magnetic properties of nanoparticles which are directly related to their applications in biomedicine. We will focus mainly on surface effects and ferrite nanoparticles, and on one diagnostic application of magnetic nanoparticles as magnetic resonance imaging contrast agents.

Thermal potentiation of chemotherapy by magnetic nanoparticles

Clinical studies have demonstrated the effectiveness of hyperthermia as an adjuvant for chemotherapy and radiotherapy. However, significant clinical challenges have been encountered, such as a broader spectrum of toxicity, lack of patient tolerance, temperature control and significant invasiveness. Hyperthermia induced by magnetic nanoparticles in high-frequency oscillating magnetic fields, commonly termed magnetic fluid hyperthermia, is a promising form of heat delivery in which thermal energy is supplied at the nanoscale to the tumor. This review discusses the mechanisms of heat dissipation of iron oxide-based magnetic nanoparticles, current methods and challenges to deliver heat in the clinic, and the current work related to the use of magnetic nanoparticles for the thermal-chemopotentiation of therapeutic drugs.

Vancomycin-modified LaB6@SiO2/Fe3O4 composite nanoparticles for near-infrared photothermal ablation of bacteria

LaB6 nanoparticles possess excellent near-infrared (NIR) photothermal conversion properties. Vancomycin can interact strongly with a broad range of Gram-positive and Gram-negative bacteria. Fe3O4 nanoparticles could be used as the carrier for magnetic separation. In this work, vancomycin and Fe3O4 nanoparticles were successfully bound onto the surface of LaB6 nanoparticles with a silica coating and carboxyl functionalization to fabricate vancomycin-modified LaB6@SiO2/Fe3O4 (Van-LaB6@SiO2/Fe3O4) composite nanoparticles as a novel nanomaterial for the NIR photothermal ablation of bacteria. From the analyses of absorption spectra, transmission electron microscopy images and X-ray diffraction patterns, the formation of Van-LaB6@SiO2/Fe3O4 composite nanoparticles was confirmed. The resulting Van-LaB6@SiO2/Fe3O4 composite nanoparticles possessed nearly superparamagnetic properties, retained the excellent NIR photothermal conversion property of LaB6 nanoparticles and could capture the bacteria Staphylococcus aureus and Escherichia coli efficiently. Owing to these capabilities, they were demonstrated to be quite efficient for the magnetic separation and NIR photothermal ablation of S. aureus and E. coli. Furthermore, the magnetic property made the Van-LaB6@SiO2/Fe3O4 composite nanoparticles useful for the magnetic assembling of bacteria, which could further enhance the photothermal ablation efficiency.

Specific targeting of angiogenesis in lung cancer with RGD-conjugated ultrasmall superparamagnetic iron oxide particles using a 4.7T magnetic resonance scanner

BACKGROUND

Angiogenesis is an essential step for tumor development and metastasis. The cell adhesion molecule avβ3 integrin plays an important role in angiogenesis and is a specific marker of tumor angiogenesis. A novel avβ3 integrin- targeted magnetic resonance (MR) imaging contrast agent utilizing Arg-Gly-Asp (RGD) and ultrasmall superparamagnetic iron oxide particles (USPIO) (referred to as RGD-USPIO) was designed and its uptake by endothelial cells was assessed both in vitro and in vivo to evaluate the angiogenic profile of lung cancer.

METHODS

USPIO were coated with -NH3+ and conjugated with RGD peptides. Prussian blue staining was performed to evaluate the specific uptake of RGD-USPIO by human umbilical vein endothelial cells (HUVECs). Targeted uptake and subcellular localization of RGD-USPIO in HUVECs were confirmed by transmission electron microscopy (TEM). The ability of RGD-USPIO to noninvasively assess avβ3 integrin positive vessels in lung adenocarcinoma A549 tumor xenografts was evaluated with a 4.7T MR scanner. Immunohistochemistry was used to detect avβ3 integrin expression and vessel distribution in A549 tumor xenografts.

RESULTS

HUVECs internalized RGD-USPIO significantly more than plain USPIO. The uptake of RGD-USPIO by HUVECs could be competitively inhibited by addition of free RGD. A significant decrease in T2 signal intensity (SI) was observed at the periphery of A549 tumor xenografts at 30 minutes (P < 0.05) and 2 hours (P < 0.01) after RGD-USPIO was injected via the tail vein. Angiogenic blood vessels were mainly distributed in the periphery of tumor xenografts with positive avβ3 integrin expression.

CONCLUSIONS

RGD-USPIO could specifically label avβ3 integrin and be taken up by HUVECs. This molecular MR imaging contrast agent can specifically evaluate the angiogenic profile of lung cancer using a 4.7T MR scanner.

Surface-functionalized nanoparticles for biosensing and imaging-guided therapeutics

In this article, the very recent progress of various functional inorganic nanomaterials is reviewed including their unique properties, surface functionalization strategies, and applications in biosensing and imaging-guided therapeutics. The proper surface functionalization renders them with stability, biocompatibility and functionality in physiological environments, and further enables their targeted use in bioapplications after bioconjugation via selective and specific recognition. The surface-functionalized nanoprobes using the most actively studied nanoparticles (i.e., gold nanoparticles, quantum dots, upconversion nanoparticles, and magnetic nanoparticles) make them an excellent platform for a wide range of bioapplications. With more efforts in recent years, they have been widely developed as labeling probes to detect various biological species such as proteins, nucleic acids and ions, and extensively employed as imaging probes to guide therapeutics such as drug/gene delivery and photothermal/photodynamic therapy.

Tracking injectable microspheres in dynamic tissues with encapsulated superparamagnetic iron oxide nanoparticles

Trackable spheres of similar size to those typically used for sustained protein delivery are prepared by incorporating superparamagnetic iron oxide (SPIO) nanoparticles into the core of poly(lactide-co-glycolide) microspheres. The visibility of injections in static and temporally in dynamic tissue systems is demonstrated. This method improves upon other, less sensitive imaging modalities in their ability to track injectable delivery systems. The results obtained confirm the localization of microspheres to the injected target area and highlight the novelty of tracking delivery vehicles for other applications.

Rapid magnetic cell delivery for large tubular bioengineered constructs

Delivery of cells into tubular tissue constructs with large diameters poses significant spatial and temporal challenges. This study describes preliminary findings for a novel process for rapid and uniform seeding of cells onto the luminal surface of large tubular constructs. Fibroblasts, tagged with superparamagnetic iron oxide nanoparticles (SPION), were directed onto the luminal surface of tubular constructs by a magnetic field generated by a k4-type Halbach cylinder device. The spatial distribution of attached cells, as measured by the mean number of cells, was compared with a conventional, dynamic, rotational cell-delivery technique. Cell loading onto the constructs was measured by microscopy and magnetic resonance imaging. The different seeding techniques employed had a significant effect on the spatial distribution of the cells (p < 0.0001). The number of attached cells at defined positions within the same construct was significantly different for the dynamic rotation technique (p < 0.05). In contrast, no significant differences in the number of cells attached to the luminal surface were found between the defined positions on the construct loaded with the Halbach cylinder. The technique described overcomes limitations associated with existing cell-delivery techniques and is amenable to a variety of tubular organs where rapid loading and uniform distribution of cells for therapeutic applications are required.

Multifunctional magnetic nanoparticles for synergistic enhancement of cancer treatment by combinatorial radio frequency thermolysis and drug delivery

Few-layer, carbon-coated, iron (C/Fe) magnetic nanoparticles (MNPs) were synthesized with controlled sizes ranging from 7 to 9 nm. The additional loading of two anti-cancer drugs, doxorubicin and erlotinib, was achieved through - stacking onto the carbon shells. Controlled release of the drugs was successfully triggered by radio frequency (RF) heating or pH variation. Based on the experimental results, C/Fe MNPs act as heat-inducing agents and are able to thermally destroy cancer cells when RF is applied. It was found that the combination of anti-cancer drugs (in particular a low dose of doxorubicin) and RF treatment demonstrates a synergistic effect in inducing cell death in pancreatic cancer cells. Our findings demonstrate that MNPs can be used as highly efficient multimodal nanocarrier agents for an integrated approach to cancer treatment involving triggered delivery of antineoplastic drugs and RF-induced thermal therapy.

Synthesis of magnetite/amphiphilic polymer composite nanoparticles as potential theragnostic agents

This study describes the synthesis of magnetite/amphiphilic polymer composite nanoparticles that can be potentially used simultaneously for cancer diagnosis and therapy. The synthesis method was a one-shot process wherein magnetite nanoparticles were mixed with core-crosslinked amphiphilic polymer (CCAP) nanoparticles, prepared using a copolymer of a urethane acrylate nonionomer (UAN) and a urethane acrylate anionomer (UAA). The CCAP nanoparticles had a hydrophobic core and a hydrophilic exterior with both PEG segments and carboxylic acid groups, wherein the magnetite nanoparticles were coordinated and stabilized. According to DLS data, the ratio of UAN to UAA and the ratio of magnetite to polymer are keys to controlling the size and thus, the stability of the composite nanoparticles. The magnetic measurement indicated that the composite nanoparticles had superparamagnetic properties and high saturation magnetization. The preliminary magnetic resonance imaging showed that the particles produced an enhanced image even when their concentration was as low as 80 microg/ml.

Chitosan oligosaccharide-stabilized ferrimagnetic iron oxide nanocubes for magnetically modulated cancer hyperthermia

Magnetic nanoparticles have gained significant attention as a therapeutic agent for cancer treatment. Herein, we developed chitosan oligosaccharide-stabilized ferrimagnetic iron oxide nanocubes (Chito-FIONs) as an effective heat nanomediator for cancer hyperthermia. Dynamic light scattering and transmission electron microscopic analyses revealed that Chito-FIONs were composed of multiple 30-nm-sized FIONs encapsulated by a chitosan polymer shell. Multiple FIONs in an interior increased the total magnetic moments, which leads to localized accumulation under an applied magnetic field. Chito-FIONs also exhibited superior magnetic heating ability with a high specific loss power value (2614 W/g) compared with commercial superparamagnetic Feridex nanoparticles (83 W/g). The magnetically guided Chito-FIONs successfully eradicated target cancer cells through caspase-mediated apoptosis. Furthermore, Chito-FIONs showed excellent antitumor efficacy on an animal tumor model without any severe toxicity.

Construction of orthogonal synchronized bi-directional field to enhance heating efficiency of magnetic nanoparticles

Magnetic hyperthermia using magnetic nanoparticles (MNPs) has attracted considerable attention as one of the promising tumor therapy. The study has been developed under single magnetic field. Recently, we found that the immobile MNP may generate more heat under two synchronous ac magnetic fields than traditional single and circular polarized fields based on model simulation result. According to this finding we constructed an orthogonal synchronized bi-directional field (OSB field). The system contained two LC resonant inverters (L: inductor, C: capacitor) and both vertical and transverse ac magnetic fields were generated by two Helmholtz coils. To reduce the interference, the axis directional of two coils were arranged orthogonally. The experiments showed that the heating ability of aggregated MNPs is greatly enhanced under this newly designed OSB field without increasing the strength of magnetic field. The OSB field system provides a promising way for future clinical hyperthermia.

Multimodal imaging guided photothermal therapy using functionalized graphene nanosheets anchored with magnetic nanoparticles

In this work, a nanoscale reduced graphene oxide-iron oxide nanoparticle (RGO-IONP) complex is noncovalently functionalized with polyethylene glycol (PEG), obtaining a RGO-IONP-PEG nanocomposite with excellent physiological stability, strong NIR optical absorbance, and superparamagnetic properties. Using this theranostic nanoprobe, in-vivo triple modal fluorescence, photoacoustic, and magnetic resonance imaging are carried out, uncovering high passive tumor targeting, which is further used for effective photothermal ablation of tumors in mice.

Targeting of primary breast cancers and metastases in a transgenic mouse model using rationally designed multifunctional SPIONs

Breast cancer remains one of the most prevalent and lethal malignancies in women. The inability to diagnose small volume metastases early has limited effective treatment of stage 4 breast cancer. Here we report the rational development and use of a multifunctional superparamagnetic iron oxide nanoparticle (SPION) for targeting metastatic breast cancer in a transgenic mouse model and imaging with magnetic resonance (MR). SPIONs coated with a copolymer of chitosan and polyethylene glycol (PEG) were labeled with a fluorescent dye for optical detection and conjugated with a monoclonal antibody against the neu receptor (NP-neu). SPIONs labeled with mouse IgG were used as a nontargeting control (NP-IgG). These SPIONs had desirable physiochemical properties for in vivo applications such as near neutral zeta potential and hydrodynamic size around 40 nm and were highly stable in serum containing medium. Only NP-neu showed high uptake in neu expressing mouse mammary carcinoma (MMC) cells which was reversed by competing free neu antibody, indicating their specificity to the neu antigen. In vivo, NP-neu was able to tag primary breast tumors and significantly, only NP-neu bound to spontaneous liver, lung, and bone marrow metastases in a transgenic mouse model of metastatic breast cancer, highlighting the necessity of targeting for delivery to metastatic disease. The SPIONs provided significant contrast enhancement in MR images of primary breast tumors; thus, they have the potential for MRI detection of micrometastases and provide an excellent platform for further development of an efficient metastatic breast cancer therapy.

Magnetic nanoparticles: an emerging technology for malignant brain tumor imaging and therapy

Magnetic nanoparticles (MNPs) represent a promising nanomaterial for the targeted therapy and imaging of malignant brain tumors. Conjugation of peptides or antibodies to the surface of MNPs allows direct targeting of the tumor cell surface and potential disruption of active signaling pathways present in tumor cells. Delivery of nanoparticles to malignant brain tumors represents a formidable challenge due to the presence of the blood-brain barrier and infiltrating cancer cells in the normal brain. Newer strategies permit better delivery of MNPs systemically and by direct convection-enhanced delivery to the brain. Completion of a human clinical trial involving direct injection of MNPs into recurrent malignant brain tumors for thermotherapy has established their feasibility, safety and efficacy in patients. Future translational studies are in progress to understand the promising impact of MNPs in the treatment of malignant brain tumors.

2, 2'-(Phenylazanediyl) diacetic acid modified Fe3O4@PEI for selective removal of cadmium ions from blood

A water-dispersible and supermagnetic nanocomposite (PAD-PEG-Fe(3)O(4)@PEI) has been successfully synthesized using polyethylenimine (PEI, Mol MW = 10000) coated supermagnetic Fe(3)O(4)-NH(2) which was modified with 2, 2'-(phenylazanediyl) diacetic acid (PAD) through the bridge of poly(ethylene glycol) (PEG, Mol MW = 2000). The average particle size of PAD-PEG-Fe(3)O(4)@PEI was determined by TEM, and was about 50 nm. From magnetic hysteresis cycles for PAD-PEG-Fe(3)O(4)@PEI at room temperature, the saturation magnetization (Ms) was shown to be 58.14 emu g(-1). Inductively coupled plasma spectrometry (ICP) analysis showed that the designed magnetic nanocomposite can remove 98% and 80% of Cd(2+) from water and blood, respectively.

Bifunctional bacterial magnetic nanoparticles for tumor targeting

Bifunctional bacterial magnetic nanoparticles (BBMPs), which present both magnetic drug targeting and tumor bio-targeting properties, have been developed by chemically coupling both doxorubicin and a galactosyl ligand on to the membrane surface of the bacterial magnetic nanoparticles (BMPs). The BBMP product has a high drug load ratio and magnetic respondence, and exhibits a narrow size distribution and is sensitive to pH to enable drug release. In comparison to doxorubicin-coupled BMPs, without modification with a galactosyl ligand, BBMPs present a higher uptake by the target asialoglycoprotein receptor (ASGP-R) expressed by HepG2 cells and display stronger cytotoxicity.