Iron Oxide Nanoparticles For Delivery Research Articles

Tumor integrin targeted theranostic iron oxide nanoparticles for delivery of caffeic acid phenethyl ester: preparation, characterization, and anti-myeloma activities.

Multiple myeloma (MM) is characterized by the accumulation of malignant plasma cells preferentially in the bone marrow. Currently, emerging chemotherapy drugs with improved biosafety profiles, such as immunomodulatory agents and protease inhibitors, have been used in clinics to treat MM in both initial therapy or maintenance therapy post autologous hematopoietic stem cell transplantation (ASCT). We previously discovered that caffeic acid phenethyl ester (CAPE), a water-insoluble natural compound, inhibited the growth of MM cells by inducing oxidative stress. As part of our continuous effort to pursue a less toxic yet more effective therapeutic approach for MM, the objective of this study is to investigate the potential of CAPE for in vivo applications by using magnetic resonance imaging (MRI)-capable superparamagnetic iron oxide nanoparticles (IONP) as carriers. Cyclo (Arg-Gly-Asp-D-Phe-Cys) (RGD) is conjugated to IONP (RGD-IONP/CAPE) to target the overexpressed αvβ3 integrin on MMcells for receptor-mediated internalization and intracellular delivery of CAPE. A stable loading of CAPE on IONP can be achieved with a loading efficiency of 48.7% ± 3.3% (wt%). The drug-release studies indicate RGD-IONP/CAPE is stable at physiological (pH 7.4) and basic pH (pH 9.5) and subject to release of CAPE at acidic pH (pH 5.5) mimicking the tumor and lysosomal condition. RGD-IONP/CAPE causes cytotoxicity specific to human MM RPMI8226, U266, and NCI-H929 cells, but not to normal peripheral blood mononuclear cells (PBMCs), with IC50s of 7.97 ± 1.39, 16.75 ± 1.62, and 24.38 ± 1.71μM after 72-h treatment, respectively. Apoptosis assays indicate RGD-IONP/CAPE induces apoptosis of RPMI8226 cells through a caspase-9 mediated intrinsic pathway, the same as applying CAPE alone. The apoptogenic effect of RGD-IONP/CAPE was also confirmed on the RPMI8226 cells co-cultured with human bone marrow stromal cells HS-5 in a Transwell model to mimic the MM microenvironment in the bone marrow. In conclusion, we demonstrate that water-insoluble CAPE can be loaded to RGD-IONP to greatly improve the biocompatibility and significantly inhibit the growth of MMcells in vitro through the induction of apoptosis. This study paves the way for investigating the MRI-trackable delivery of CAPE for MM treatment in animal models in the future.

Improved tumour delivery of iron oxide nanoparticles for magnetic hyperthermia therapy of melanoma via ultrasound guidance and 111In SPECT quantification.

Magnetic field hyperthermia relies on the intra-tumoural delivery of magnetic nanoparticles by interstitial injection, followed by their heating on exposure to a remotely-applied alternating magnetic field (AMF). This offers a potential sole or adjuvant route to treating drug-resistant tumours for which no alternatives are currently available. However, two challenges in nanoparticle delivery currently hinder the effective clinical translation of this technology: obtaining enough magnetic material within the tumour to enable sufficient heating; and doing this accurately to limit or avoid damage to surrounding healthy tissue. A further complication is the lack of established methods to non-invasively quantify nanoparticle biodistribution, which is necessary to evaluate the performance of improved delivery strategies. Here we employ 111In radiolabelling and single-photon emission computed tomography (SPECT) to non-invasively quantify distribution of a clinical grade iron-oxide-based nanoparticle in a mouse model of melanoma. We show that compared to manual injection, ultrasound guided delivery together with syringe-pump-controlled infusion improves both the nanoparticle concentration within the tumour, and the accuracy of delivery - reducing off-target peri-tumoural delivery. Following AMF heating, injected melanomas shrank significantly compared to non-injected controls, validating therapeutic efficacy. Systemic off-target delivery was quantified and extrapolated to predict off-target energy absorbance within safe limits for the main sites of background accumulation. With many nanoparticle-based therapies currently in development for cancer, this image-guided delivery strategy has wide potential impact beyond the field of magnetic hyperthermia. Future use in representative patient cohorts would also be enabled by the high clinical availability of both SPECT and ultrasound imaging.

Design and development of a magnetic field-enabled platform for delivering polymer-coated iron oxide nanoparticles to breast cancer cells

The current literature mostly contains relatively vague descriptions of techniques for implementing in vitro magnetic targeting delivery of iron oxide nanoparticles (IONPs), leading to irreproducible processes and incomparable findings. This discrepancy often arises from the varying exposure of IONPs to the non-uniform magnetic field and differences in the concentration of the polymer-coated IONPs. Hence, we meticulously designed and built a system comprising a platform constructed from polyoxymethylene sheets, which securely holds the permanent magnets, and the cell culture plate. We also tailored the preparation process of the IONPs and the in vitro toxicity studies. The inherent characteristics of IONPs are further enhanced by their coating with natural polymers, alginate (Alg) and chitosan (CS).•The design and construction of the platform were carried out using a laser engraving/cutting machine along with graphic design software. The precise locations of the permanent magnets relative to the cell culture plate were determined via a Gaussmeter.•The quantities of the components in the formulation and the method for fabricating the CS/Alg-coated IONPs (CS/Alg-IONPs) were optimized to ensure that the desired physicochemical properties were obtained.•The cultivation and cytotoxicity evaluation of the fabricated CS/Alg-IONPs against MCF-7 breast cancer cells were described.

Targeted Imaging of Lung Cancer with Hyperpolarized 129Xe MRI Using Surface-Modified Iron Oxide Nanoparticles as Molecular Contrast Agents.

Hyperpolarized 129Xe (HP 129Xe) MRI enables functional imaging of various lung diseases but has been scarcely applied to lung cancer imaging. The aim of this study is to investigate the feasibility of targeted imaging of lung cancer with HP 129Xe MRI using surface-modified iron oxide nanoparticles (IONPs) as molecular targeting contrast agents. A mouse model of lung cancer (LC) was induced in nine mice by intra-peritoneal injection of urethane. Three months after the urethane administration, the mice underwent lung imaging with HP 129Xe MRI at baseline (0 h). Subsequently, the LC group was divided into two sub-groups: mice administered with polyethylene glycol-coated IONPs (PEG-IONPs, n = 4) and folate-conjugated dextran-coated IONPs (FA@Dex-IONPs, n = 5). The mice were imaged at 3, 6, and 24 h after the intravenous injection of IONPs. FA@Dex-IONPs mice showed a 25% reduction in average signal intensity at cancer sites at 3 h post injection, and a 24% reduction at 24 h post injection. On the other hand, in PEG-IONPs mice, while a signal reduction of approximately 28% was observed at cancer sites at 3 to 6 h post injection, the signal intensity was unchanged from that of the baseline at 24 h. Proton MRI of LC mice (n = 3) was able to detect cancer five months after urethane administration, i.e., later than HP 129Xe MRI (3 months). Furthermore, a significant decrease in averaged 1H T2 values at cancer sites was observed at only 6 h post injection of FA@Dex-IONPs (p < 0.05). As such, the targeted delivery of IONPs to cancer tissue was successfully imaged with HP 129Xe MRI, and their surface modification with folate likely has a high affinity with LC, which causes overexpression of folate receptors.

Targeted Ultrafine Iron Oxide Nanoparticles for Delivery of the Topoisomerase Inhibitor SN38 and Ovarian Cancer Treatment

Ovarian cancer remains a challenge to decrease mortality and improve diagnostic efficiency in gynecological cancers. To develop a delivery system capable of efficient cancer cell targeting and delivering novel efficacious therapeutics, we assembled folic acid (FA) conjugated ultrafine iron oxide nanoparticles (uIONP) with encapsulation of DNA topoisomerase inhibitor SN38, which target ovarian cancer cells with over-expression of folate receptor alpha (FRα) and deliver SN38 to induce apoptosis. The assembled FA-uIONP-SN38 exhibited higher drug loading efficiency than the larger counterparts with core diameters more than 10 nm. The targeting specificity of FA-uIONP-SN38 for SKOV-3 cancer cells was validated, with HEK293 kidney cells and Raw264.7 macrophages as non-targeted cell line control. It was found that more SKOV-3 cancer cells were killed due to apoptosis by FA-uIONP-SN38 at the same SN38 dosages compared with uIONP-SN38 and free SN38, respectively. The delivery of this inhibitor to SKOV-3 cancer cells by FRα-targeted FA-uIONP carrier was enhanced by about 10-folds with less cytotoxicity comparing to the free drug SN38. The developed FA-uIONP-SN38 holds a great potential as a theranostic approach in treating ovarian cancer.

Enhanced Detection of Desmoplasia by Targeted Delivery of Iron Oxide Nanoparticles to the Tumour-Specific Extracellular Matrix.

Diagnostic imaging of aggressive cancer with a high stroma content may benefit from the use of imaging contrast agents targeted with peptides that have high binding affinity to the extracellular matrix (ECM). In this study, we report the use of superparamagnetic iron-oxide nanoparticles (IO-NP) conjugated to a nonapeptide, CSGRRSSKC (CSG), which specifically binds to the laminin-nidogen-1 complex in tumours. We show that CSG-IO-NP accumulate in tumours, predominantly in the tumour ECM, following intravenous injection into a murine model of pancreatic neuroendocrine tumour (PNET). In contrast, a control untargeted IO-NP consistently show poor tumour uptake, and IO-NP conjugated to a pentapeptide, CREKA that bind fibrin clots in blood vessels show restricted uptake in the angiogenic vessels of the tumours. CSG-IO-NP show three-fold higher intratumoral accumulation compared to CREKA-IO-NP. Magnetic resonance imaging (MRI) T2-weighted scans and T2 relaxation times indicate significant uptake of CSG-IO-NP irrespective of tumour size, whereas the uptake of CREKA-IO-NP is only consistent in small tumours of less than 3 mm in diameter. Larger tumours with significantly reduced tumour blood vessels show a lack of CREKA-IO-NP uptake. Our data suggest CSG-IO-NP are particularly useful for detecting stroma in early and advanced solid tumours.

Delivery of Iron Oxide Nanoparticles into Primordial Germ Cells in Sturgeon.

Nanoparticles are finding increasing applications in diagnostics, imaging and therapeutics in medicine. Iron oxide nanoparticles (IONs) have received significant interest of scientific community due to their distinctive properties. For the first time, we have delivered IONs into germ cells in any species. Our results showed that sturgeon primordial germ cells (PGCs) delivered with IONs could be detected until seven days post fertilization (dpf) under fluorescent microscope and at 22 dpf by micro-CT. Delivery of IONs into cells could be helpful for studying germ cell biology and the improvement of germ cell-based bio-technologies as isolation of PGCs using magnetic activated cell sorting or application of hyperthermia for a host sterilization purpose. Intriguingly, in our study, we did not find any toxic effects of IONs on the survival and hatching rates of sturgeon embryos when compared with embryos injected with FITC-dextran only.

Synthesis and Characterization of Cationic Polymer Coated Iron Oxide Nanoparticles for Delivery of siRNA and Selective Gene Silencing

Synthesis and Characterization of Cationic Polymer Coated Iron Oxide Nanoparticles for Delivery of siRNA and Selective Gene Silencing

New strategies in vaccine design for the induction of CD8 T cell responses using biodegradable iron oxide nanoparticles

Abstract For vaccines targeting diseases such as malaria and cancer, CD8 T cell responses are vital. Traditional adjuvants, like alum, are incapable of inducing these responses and thus new delivery strategies are required. Previously, we have shown that biocompatible polystyrene nanoparticles (PSNPs) (carboxylate, 40–50 nm) can induce potent cytotoxic T cell and antibody responses when conjugated to antigen and can protect mice against experimental tumours or clear large established tumours after a single immunization. As a biodegradable alternative; we synthesised ~50 nm iron oxide nanoparticles (IONPs) stabilized with the polysaccharide pullulan. The IONPs share similar characteristics (size, charge and shape) with the PSNPs, are stable, non-toxic, rapidly taken up by dendritic cells in vitro and are considered inert as they do not upregulate costimulatory markers. The adjuvant/carrier capabilities of IONPs when conjugated to model antigen ovalbumin (OVA) were assessed in vivo. IONPs can induce strong antibody responses but failed to boost the T cell response (Th1 and Th2) after two immunisations, despite their similarity to PSNPs. This implies that the composition of a NP can affect its interactions with the immune system and as such its behaviour as a carrier. To produce an IONP delivery system in which CD8 T cells could also be induced in addition to strong antibody responses, IONPs were co-delivered with the TLR9 agonist CpG. This led to > 2-fold increases in CD8 T cell and antibody responses above either IONPs or CpG alone. Therefore, these biodegradable particles have the capacity to synergize with an inflammatory adjuvant and provide a new strategy for vaccine delivery focused on the induction of CD8 T cell responses.

Tumor Penetrating Theranostic Nanoparticles for Enhancement of Targeted and Image-guided Drug Delivery into Peritoneal Tumors following Intraperitoneal Delivery.

The major obstacles in intraperitoneal (i.p.) chemotherapy of peritoneal tumors are fast absorption of drugs into the blood circulation, local and systemic toxicities, inadequate drug penetration into large tumors, and drug resistance. Targeted theranostic nanoparticles offer an opportunity to enhance the efficacy of i.p. therapy by increasing intratumoral drug delivery to overcome resistance, mediating image-guided drug delivery, and reducing systemic toxicity. Herein we report that i.p. delivery of urokinase plasminogen activator receptor (uPAR) targeted magnetic iron oxide nanoparticles (IONPs) led to intratumoral accumulation of 17% of total injected nanoparticles in an orthotopic mouse pancreatic cancer model, which was three-fold higher compared with intravenous delivery. Targeted delivery of near infrared dye labeled IONPs into orthotopic tumors could be detected by non-invasive optical and magnetic resonance imaging. Histological analysis revealed that a high level of uPAR targeted, PEGylated IONPs efficiently penetrated into both the peripheral and central tumor areas in the primary tumor as well as peritoneal metastatic tumor. Improved theranostic IONP delivery into the tumor center was not mediated by nonspecific macrophage uptake and was independent from tumor blood vessel locations. Importantly, i.p. delivery of uPAR targeted theranostic IONPs carrying chemotherapeutics, cisplatin or doxorubicin, significantly inhibited the growth of pancreatic tumors without apparent systemic toxicity. The levels of proliferating tumor cells and tumor vessels in tumors treated with the above theranostic IONPs were also markedly decreased. The detection of strong optical signals in residual tumors following i.p. therapy suggested the feasibility of image-guided surgery to remove drug-resistant tumors. Therefore, our results support the translational development of i.p. delivery of uPAR-targeted theranostic IONPs for image-guided treatment of peritoneal tumors.

Biodistribution of negatively charged iron oxide nanoparticles (IONPs) in mice and enhanced brain delivery using lysophosphatidic acid (LPA)

Effective treatment of brain disorders requires a focus on improving drug permeability across the blood–brain barrier (BBB). Herein, we examined the pharmacokinetic properties of negatively charged iron oxide nanoparticles (IONPs) and the capability of using lysophosphatidic acid (LPA) to transiently disrupt the tight junctions and allow IONPs to enter the brain. Under normal conditions, IONPs had a plasma half-life of six minutes, with the liver and spleen being the major organs of deposition. Treatment with LPA enhanced accumulation of IONPs in the brain and spleen (approximately 4-fold vs. control). LPA and IONP treated mice revealed no sign of peripheral immune cell infiltration in the brain and no significant activation of microglia or astrocytes. These studies show improved delivery efficiency of IONPs following LPA administration. Our findings suggest transient disruption of the BBB may be a safe and effective method for increasing IONP delivery to the brain.

Development of anti-HER2 fragment antibody conjugated to iron oxide nanoparticles for in vivo HER2-targeted photoacoustic tumor imaging

Photoacoustic (PA) imaging is a promising imaging modality that provides biomedical information with high sensitivity and resolution. Iron oxide nanoparticles (IONPs) have been regarded as remarkable PA contrast agents because of their low toxicity and biodegradable properties. However, IONP delivery is restricted by its modest leakage and retention in tumors. In this study, we designed IONPs (20nm, 50nm, and 100nm) conjugated with anti-HER2 moieties [whole IgG, single-chain fragment variable (scFv), and peptide] for HER2-targeted PA tumor imaging. The binding affinity, cellular uptake, and in vivo biodistribution were examined. We propose 20-nm anti-HER2 scFv-conjugated IONPs (SNP20) as a novel PA contrast agent. SNP20 demonstrated high affinity and specific binding to HER2-expressing cells; it selectively visualized HER2-positive tumors in PA imaging studies. These data indicate that SNP20 is a potential PA contrast agent for imaging of HER2-expressing tumors. From the Clinical EditorIron oxide nanoparticles have been demonstrated to be good contrast agents for tumor imaging. They may also be useful in photoacoustic (PA) imaging, which can provide high sensitivity data and image resolution. The authors here coupled iron oxide nanoparticles with anti-HER2 antibody fragment and showed significant retention of these nanoparticles in tumors. This combination may provide another option for enhanced imaging of tumors.

Abstract B33: Multifunctional formulation for dual imaging and magnetic hyperthermia therapy of liver cancer: A preclinical feasibility study

Abstract Purpose: Magnetic hyperthermia with local delivery of iron oxide nanoparticles (NP) offers a promising therapeutic alternative for primary liver cancer. Our aim was to explore the therapeutic potential of local NP injection, using a nanoparticle- ethiodized oil (lipiodol) emulsion (NLE), in xenograft HepG2 mouse models of liver cancer and in orthotopic VX2 rabbit liver cancer models. Materials/Methods: NLE comprises lipiodol (50% w/v), polysorbate 20 (Tween 20, 0.2% w/v) and biocompatible Fe3O4 nanoparticles (BNF, 49.8% w/v). In vivo mice experiments included intra-tumor injections of a) NLE (n=20), b) BNF (n=12), c) PBS (n=14) in Foxnu1 mice bearing flank xenograft HepG2 tumors with and without AMF hyperthermia exposure (15-min, 300-700 Gauss, 150 kHz, 18 hours post-injection, with core and peri-tumor temperature measurements). Mice were either euthanized at 1-7 days or observed for tumor growth delay. Rabbit experiments included intra-arterial injections of NLE (n=8) with (n=4) and without (n=4) subsequent AMF hyperthermia exposure (20 min, 300 Gauss, 150 KHz, 48 hours (n=2) or 7 days (n=2) post-injection, with core and peri-tumor temperature measurements). Rabbits were euthanized at 3 or 7 days. Rabbits were imaged at baseline and before euthanasia in a clinical 320-slice CT scanner, as well as in a clinical 3T MR scanner. Imaging analysis included CT perfusion measurements, MR T2* measurements and co-registration of lipiodol and iron content. Pathologic analysis for all studies included evaluation of tumor necrosis, lipiodol and iron distribution.. Results: In mice, average maximum tumor temperature increase was 7.4±0.5°C for NLE (n=8) and 5.4±0.3°C for NP (n=5). At 24 days, there was a 4-fold difference in tumor growth delay between PBS and NLE-AMF heated tumors. Increased tumor necrosis was observed at 7 days in the NLE group. Intra-tumor iron distribution of NLE samples showed a characteristic distribution of NLE along the vascular tumor pathways at the tumor rim. In rabbits, average maximum tumor temperature increase was 3.2±0.5°C. Similarly, increased tumor necrosis was observed at 7 days and intra-tumor iron was seen deposited at the tumor rim. While CT imaging revealed primarily lipiodol deposition, MR imaging was very sensitive in detecting iron distribution, even in non-targeted areas. Conclusion: Preliminary in vivo data of the proposed NLE formulation for magnetic hyperthermia and dual imaging show potential for intra-tumor delivery and therapy in HepG2 xenograft mice models and intra-arterial delivery and therapy in the VX2 liver cancer model, with MRI/CT capabilities. Histological analysis of NLE treated tumors confirmed intra-tumour iron deposition with increased cellular damage. Initial results are encouraging and motivate further development for clinical translation. Citation Format: Eleni Liapi, Sahar Mirpour, Madhav Seshadri, Anilchandra Attaluri, Michele Wabler, Haoming Zhou, Robert Ivkov. Multifunctional formulation for dual imaging and magnetic hyperthermia therapy of liver cancer: A preclinical feasibility study. [abstract]. In: Proceedings of the Third AACR International Conference on Frontiers in Basic Cancer Research; Sep 18-22, 2013; National Harbor, MD. Philadelphia (PA): AACR; Cancer Res 2013;73(19 Suppl):Abstract nr B33.

Active Targeting Using HER‐2‐Affibody‐Conjugated Nanoparticles Enabled Sensitive and Specific Imaging of Orthotopic HER‐2 Positive Ovarian Tumors

Despite advances in cancer diagnosis and treatment, ovarian cancer remains one of the most fatal cancer types. The development of targeted nanoparticle imaging probes and therapeutics offers promising approaches for early detection and effective treatment of ovarian cancer. In this study, HER-2 targeted magnetic iron oxide nanoparticles (IONPs) are developed by conjugating a high affinity and small size HER-2 affibody that is labeled with a unique near infrared dye (NIR-830) to the nanoparticles. Using a clinically relevant orthotopic human ovarian tumor xenograft model, it is shown that HER-2 targeted IONPs are selectively delivered into both primary and disseminated ovarian tumors, enabling non-invasive optical and MR imaging of the tumors as small as 1 mm in the peritoneal cavity. It is determined that HER-2 targeted delivery of the IONPs is essential for specific and sensitive imaging of the HER-2 positive tumor since we are unable to detect the imaging signal in the tumors following systemic delivery of non-targeted IONPs into the mice bearing HER-2 positive SKOV3 tumors. Furthermore, imaging signals and the IONPs are not detected in HER-2 low expressing OVCAR3 tumors after systemic delivery of HER-2 targeted-IONPs. Since HER-2 is expressed in a high percentage of ovarian cancers, the HER-2 targeted dual imaging modality IONPs have potential for the development of novel targeted imaging and therapeutic nanoparticles for ovarian cancer detection, targeted drug delivery, and image-guided therapy and surgery.

A comprehensive analysis of transfection-assisted delivery of iron oxide nanoparticles to dendritic cells

Polylysine (PL) has been used to facilitate dendritic cell (DC) uptake of super paramagnetic iron oxide (SPIO) nanoparticles for use in magnetic resonance imaging (MRI). In this work, we examined the effect of PL on cell toxicity and induction of cell maturation as manifested by the up-regulation of surface molecules. We found that PL became toxic to bone marrow-derived DCs (BMDCs) at the 10μg/ml threshold. Incubation of BMDCs with 20μg/ml of PL for 1h resulted in approximately 90% cell death. However, addition of SPIO nanoparticles rescued DCs from PL-induced death as the combination of SPIO with PL did not cause cytotoxicity until the PL concentration was 1000μg/ml. Prolonged exposure to PL induced BMDC maturation as noted by the expression of surface molecules such as MHC class II, CD40, CCR7 and CD86. However, the combination of SPIO and PL did not induce BMDC maturation at 1h. However prolonged exposure to SPIO nanoparticles induced CD40 expression and protein expression of TNFα and KC. The data suggest that the use of PL to enhance the labeling of DCs with SPIO nanoparticles is a dedicated work. Appropriate calibration of the incubation time and concentrations of PL and SPIO nanoparticles is crucial to the development of MRI technology for noninvasive imaging of DCs in vivo. From the Clinical EditorThe authors of this study present detailed data on toxicity and efficiency of polylysine-facilitated uptake of USPIO-s by dendritic cells for cell-specific MR imaging.

In vivo nanoneurotoxicity screening using oxidative stress and neuroinflammation paradigms

Iron oxide nanoparticles (IONPs) are promising neuroimaging agents and molecular cargo across neurovascular barriers. Development of intrinsically safe IONP chemistries requires a robust in vivo nanoneurotoxicity screening model. Herein, we engineered four IONPs of different surface and core chemistries: DMSA-Fe2O3, DMSA-Fe3O4, PEG-Fe3O4 and PEG-Au-Fe3O4. Capitalizing on the ability of the peripheral nervous system to recruit potent immune cells from circulation, we characterized a spatiotemporally controlled platform for the study of in vivo nanobiointerfaces with hematogenous immune cells, neuroglial and neurovascular units after intraneural IONP delivery into rat sciatic nerve. SQUID magnetometry and histological iron stain were used for IONP tracking. Among the IONPs, DMSA-Fe2O3 NPs were potent pro-apoptotic agents in nerve, with differential ability to regulate oxidative stress, inflammation and apoptotic signaling in neuroglia, macrophages, lymphocytes and endothelial cells. This platform aims to facilitate the development of predictive paradigms of nanoneurotoxicity based on mechanistic investigation of relevant in vivo bio-nanointerfaces. From the Clinical EditorThis team of investigators report the development of a platform that enables screening of iron oxide nanoparticles from the standpoint of their potential neurotoxicity, utilizing rat sciatic nerves. Such screening tools are clearly needed with the potential advent of iron oxide nanoparticle-based diagnostic and therapeutic approaches.

9:12 AM Abstract No. 194 - Expression of angiogenic factors and tumoral response after transcatheter intraarrterial treatment of rabbit VX-2 liver tumors using a novel iron-oxide nanoparticle drug delivery system

Purpose To investigate tissue response and expression of angiogenic factors after targeted transcatheter intraarterial (IA) treatment of the rabbit VX-2 liver tumor using iron-oxide nanoparticles (IONP) for drug delivery. Materials and Methods VX-2 tumors were implanted in the left liver lobe of 30 New Zealand White rabbits which were subsequently treated when tumor size reached 2 cm. Two groups received 1.0 mg/kg Doxorubicin (Dox) either by IA IONP delivery via the left hepatic artery (n=14) or IV IONP delivery via the marginal ear vein. Another 2 groups received free Doxorubicin either by IA (n=4) or IV (n=6) administration. Animals were sacrificed serially at 3 hours, 24 hours, and 7 days after treatment. Liver explants were collected for immunohistochemistry with hypoxia-inducible factor 1-alpha (HIF1-α), vascular endothelial growth factor (VEGF), platelet-derived growth factor receptor alpha (PDGFR-α), and platelet-derived growth factor receptor beta (PDGFR-β) in addition to histologic scoring of necrosis and microvascular invasion in both tumoral and peritumoral areas. Results were analyzed using statistical software. Results For IA IONP delivery of Doxorubicin, tumoral PDGR-α levels decreased significantly as sacrifice times increased from 3 to 24 hrs (3 vs 2.12; p=0.0367). Additionally, tumoral HIF1-α levels increased significantly as sacrifice time increased from 3 hrs to 7 days (2 vs 3; p=0.0179). Post-treatment peritumoral levels of PDGR-α were significantly higher for the IA IONP treatment group compared to IV IONP delivery (2.428 vs 1.8333; p=0.0436). Overall, as sacrifice times increased from 3 hrs, 24 hrs, and 7 days, peritumoral levels of VEGF increased significantly (2.25 vs 2.77; p=.0294). Post-treatment levels of VEGF also increased in tumoral areas from 24 hrs to 7 days (2.5 vs 3; p=.0415). Conclusion Targeted intraarterial iron-oxide nanoparticle-mediated delivery of chemotherapy induces an exact tissue response and sustained differential expression of immunohistocemical indicators of angiogenesis and hypoxia in both tumoral and peritumoral areas for several days after treatment.

Microworms swallow the nanobait: the use of nanocoated microbial cells for the direct delivery of nanoparticles into Caenorhabditis elegans

The application of in vivo models in assessing the toxicity of nanomaterials is currently regarded as a promising way to investigate the effects of nanomaterials on living organisms. In this paper we introduce a novel method to deliver nanomaterials into Caenorhabditis elegans nematodes. Our approach is based on using nanoparticle-coated microbial cells as "nanobait", which are ingested by nematodes as a sole food source. We found that nematodes feed on the nanocoated bacteria (Escherichia coli) and microalgae (Chlorella pyrenoidosa) ingesting them via pharyngeal pumping, which results in localization of nanoparticles inside the digestive tract of the worms. Nanoparticles were detected exclusively inside the intestine, indicating the efficient delivery based on microbial cells. Delivery of iron oxide nanoparticles results in magnetic labelling of living nematodes, rendering them magnetically-responsive. The use of cell-mediated delivery of nanoparticles can be applied to investigate the toxicity of polymer-coated magnetic nanoparticles and citrate-capped silver nanoparticles in Caenorhabditis elegans in vivo.

Image-guided targeted intraarterial delivery of chemotherapy drug loaded iron oxide nanoparticles to rabbit liver cancer model.

e14734 Background: To develop an enhanced drug delivery system to liver tumors using novel MRI traceable iron oxide nanoparticles (IONP) loaded with doxorubicin and to investigate biodistribution of deliverednanoparticle and by assessing intratumoral and normal liver tissue concentrations after targeted (IA) versus systemic (IV) administration. Methods: Paramagnetic IONP (core and hydrodynamic size of 10 nm and 23 nm, respectively) coated with amphiphilic polymers were non-covalently loaded with hydrophobic doxorubicin; whose presence was confirmed by optical absorption spectrum. VX2 liver tumors were induced in the left lobe of 12 rabbits, allowed to grow for 2 weeks to a size of 2 cm, and were subsequently divided into 2 treatment groups, each receiving 1 mg/kg body weight of doxorubicin via IONP. Group 1 received IA administration to the left hepatic artery under fluoroscopy, and Group 2 received IV administration via the marginal ear vein. Animals were sacrificed 24 hours after treatment. Tumor and liver sections were collected and iron concentrations of tumor and liver tissues were determined by the colorimetric method with iron binding 1,10-phenanthroline at 508 nm. Analysis of tissue iron concentrations in different groups was performed using a standard t-test, with p<0.05 considered significant. Results: Intratumoral and peritumoral concentrations of IONP were significantly higher 24 hours after IA administration than IV (1.54 vs 1.03 mg Fe/g , p=0.019), given at the same dosage. Additionally, 24 hours after treatment, the group receiving IA therapy showed significantly higher nanoparticle concentrations in the left hepatic lobe in comparison to the IV group (1.63 vs 1.34 mg Fe/g, p=0.0226). Conclusions: Targeted IA delivery significantly enhances intratumoral and peritumoral uptake of IONP when compared to IV. Targeted intraarterial delivery of IONP carrying doxorubincin can serve as a powerful tool in serving as a vehicle to deliver chemotherapy drugs to liver tumors. To further evaluate the potential of this drug delivery method, future studies will correlate the biodistrubution of the IONP to drug concentrations and findings on histology, imaging, tumor response.

Dual Enzyme-like Activities of Iron Oxide Nanoparticles and Their Implication for Diminishing Cytotoxicity

Iron oxide nanoparticles (IONPs) are frequently used in biomedical applications, yet their toxic potential is still a major concern. While most studies of biosafety focus on cellular responses after exposure to nanomaterials, little is reported to analyze reactions on the surface of nanoparticles as a source of cytotoxicity. Here we report that different intracellular microenvironment in which IONPs are located leads to contradictive outcomes in their abilities to produce free radicals. We first verified pH-dependent peroxidase-like and catalase-like activities of IONPs and investigated how they interact with hydrogen peroxide (H(2)O(2)) within cells. Results showed that IONPs had a concentration-dependent cytotoxicity on human glioma U251 cells, and they could enhance H(2)O(2)-induced cell damage dramatically. By conducting electron spin resonance spectroscopy experiments, we showed that both Fe(3)O(4) and γ-Fe(2)O(3) nanoparticles could catalyze H(2)O(2) to produce hydroxyl radicals in acidic lysosome mimic conditions, with relative potency Fe(3)O(4) > γ-Fe(2)O(3), which was consistent with their peroxidase-like activities. However, no hydroxyl radicals were observed in neutral cytosol mimic conditions with both nanoparticles. Instead, they decomposed H(2)O(2) into H(2)O and O(2) directly in this condition through catalase-like activities. Transmission electron micrographs revealed that IONPs located in lysosomes in cells, the acidic environment of which may contribute to hydroxyl radical production. This is the first study regarding cytotoxicity based on their enzyme-like activities. Since H(2)O(2) is continuously produced in cells, our data indicate that lysosome-escaped strategy for IONP delivery would be an efficient way to diminish long-term toxic potential.