Gelatin/nanoceria nanocomposite fibers as antioxidant scaffolds for neuronal regeneration.

BACKGROUND: The design of efficient nerve conduits able to sustain the axonal outgrowth and its guidance towards appropriate targets is of paramount importance in nerve tissue engineering. METHODS: In this work, we propose the preparation of highly aligned nanocomposite fibers of gelatin/cerium oxide nanoparticles (nanoceria), prepared by electrospinning. Nanoceria are powerful self-regenerative antioxidant nanomaterials, that behave as strong reactive oxygen species scavengers, and among various beneficial effects, they have been proven to inhibit the cell senescence and to promote the neurite sprouting. RESULTS: After a detailed characterization of the developed substrates, they have been tested on neuron-like SH-SY5Y cells, demonstrating strong antioxidant properties and beneficial multi-cue effects in terms of neurite development and alignment. CONCLUSIONS: Obtained findings suggest efficiency of the proposed substrates in providing combined topographical stimuli and antioxidant effects to cultured cells. GENERAL SIGNIFICANCE: Proposed nanocomposite scaffolds represent a promising approach for nerve tissue engineering and regenerative medicine.

Oil/water nano-emulsion loaded with cobalt ferrite oxide nanocubes for photo-acoustic and magnetic resonance dual imaging in cancer: in vitro and preclinical studies.

Dual imaging dramatically improves detection and early diagnosis of cancer. In this work we present an oil in water (O/W) nano-emulsion stabilized with lecithin and loaded with cobalt ferrite oxide (Co0.5Fe2.5O4) nanocubes for photo-acoustic and magnetic resonance dual imaging. The nanocarrier is responsive in in vitro photo-acoustic and magnetic resonance imaging (MRI) tests. A clear and significant time-dependent accumulation in tumor tissue is shown in in vivo photo-acoustic studies on a murine melanoma xenograft model. The proposed O/W nano-emulsion exhibits also high values of r2/r1 (ranging from 45 to 85, depending on the magnetic field) suggesting a possible use as T2 weighted image contrast agents. In addition, viability and cellular uptake studies show no significant cytotoxicity on the fibroblast cell line. We also tested the O/W nano-emulsion loaded with curcumin against melanoma cancer cells demonstrating a significant cytotoxicity and thus showing possible therapeutic effects in addition to the in vivo imaging.

Interactions of skin with gold nanoparticles of different surface charge, shape, and functionality.

The interactions between skin and colloidal gold nanoparticles of different physicochemical characteristics are investigated. By systematically varying the charge, shape, and functionality of gold nanoparticles, the nanoparticle penetration through the different skin layers is assessed. The penetration is evaluated both qualitatively and quantitatively using a variety of complementary techniques. Inductively coupled plasma optical emission spectrometry (ICP-OES) is used to quantify the total number of particles which penetrate the skin structure. Transmission electron microscopy (TEM) and two photon photoluminescence microscopy (TPPL) on skin cross sections provide a direct visualization of nanoparticle migration within the different skin substructures. These studies reveal that gold nanoparticles functionalized with cell penetrating peptides (CPPs) TAT and R7 are found in the skin in larger quantities than polyethylene glycol-functionalized nanoparticles, and are able to enter deep into the skin structure. The systematic studies presented in this work may be of strong interest for developments in transdermal administration of drugs and therapy.

Pilot in vivo investigation of cerium oxide nanoparticles as a novel anti-obesity pharmaceutical formulation.

Obesity is a worldwide pathological condition that strongly impairs human health, and, to date, no effective therapy against excessive fat accumulation has been found yet. Since overweight correlates with an increased oxidative stress, our aim is to investigate the antioxidant effects of cerium oxide nanoparticles (nanoceria) as a potential pharmaceutical approach for the treatment of obesity. Nanoceria were tested both in vitro and in vivo; they were proven to interfere with the adipogenic pathway by reducing the mRNA transcription of genes involved in adipogenesis, and by hindering the triglycerides accumulation in 3T3-L1 pre-adipocytes. Nanoceria, intraperitonally injected in Wistar rats, did not show appreciable toxic effects, but instead efficiently contributed in reducing the weight gain and in lowering the plasma levels of insulin, leptin, glucose and triglycerides. FROM THE CLINICAL EDITOR: Obesity is now a significant problem worldwide. To date, obesity surgery remains the best treatment for weight reduction. Much research has been conducted to discover an effective pharmacological treatment against obesity. In this article, the authors continued their previous work in studying the anti-adipogenic properties of cerium oxide nanoparticles. The antioxidant effects of nanoceria were studied in in vitro and in vivo experiments. It was shown in animal model that nanoceria could reduce body weight effectively. These promising results may provide a novel treatment in the clinical setting in the future.

Interactions of human endothelial cells with gold nanoparticles of different morphologies.

The interactions between noncancerous, primary endothelial cells and gold nanoparticles with different morphologies but the same ligand capping are investigated. The endothelial cells are incubated with gold nanospheres, nanorods, hollow gold spheres, and core/shell silica/gold nanocrystals, which are coated with monocarboxy (1-mercaptoundec-11-yl) hexaethylene glycol (OEG). Cell viability studies show that all types of gold particles are noncytotoxic. The number of particles taken up by the cells is estimated using inductively coupled plasma (ICP), and are found to differ depending on particle morphology. The above results are discussed with respect to heating efficiency. Using experimental data reported earlier and theoretical model calculations which take into account the physical properties and distribution of particles in the cellular microenvironment, it is found that collective heating effects of several cells loaded with nanoparticles must be included to explain the observed viability of the endothelial cells.

Co-loading of doxorubicin and iron oxide nanocubes in polycaprolactone fibers for combining Magneto-Thermal and chemotherapeutic effects on cancer cells.

Among the strategies to fight cancer, multi-therapeutic approaches are considered as a wise choice to put in place multiple weapons to suppress tumors. In this work, to combine chemotherapeutic effects to magnetic hyperthermia when using biocompatible scaffolds, we have established an electrospinning method to produce nanofibers of polycaprolactone loaded with magnetic nanoparticles as heat mediators to be selectively activated under alternating magnetic field and doxorubicin as a chemotherapeutic drug. Production of the fibers was investigated with iron oxide nanoparticles of peculiar cubic shape (at 15 and 23 nm in cube edges) as they provide benchmark heat performance under clinical magnetic hyperthermia conditions. With 23 nm nanocubes when included into the fibers, an arrangement in chains was obtained. This linear configuration of magnetic nanoparticles resemble that of the magnetosomes, produced by magnetotactic bacteria, and our magnetic fibers exhibited remarkable heating effects as the magnetosomes. Magnetic fiber scaffolds showed excellent biocompatibility on fibroblast cells when missing the chemotherapeutic agent and when not exposed to magnetic hyperthermia as shown by viability assays. On the contrary, the fibers containing both magnetic nanocubes and doxorubicin showed significant cytotoxic effects on cervical cancer cells following the exposure to magnetic hyperthermia. Notably, these tests were conducted at magnetic hyperthermia field conditions of clinical use. As here shown, on the doxorubicin sensitive cervical cancer cells, the combination of heat damage by magnetic hyperthermia with enhanced diffusion of doxorubicin at therapeutic temperature are responsible for a more effective oncotherapy.

Uncovering the Magnetic Particle Imaging and Magnetic Resonance Imaging Features of Iron Oxide Nanocube Clusters.

Multifunctional imaging nanoprobes continue to garner strong interest for their great potential in the detection and monitoring of cancer. In this study, we investigate a series of spatially arranged iron oxide nanocube-based clusters (i.e., chain-like dimer/trimer, centrosymmetric clusters, and enzymatically cleavable two-dimensional clusters) as magnetic particle imaging and magnetic resonance imaging probes. Our findings demonstrate that the short nanocube chain assemblies exhibit remarkable magnetic particle imaging signal enhancement with respect to the individually dispersed or the centrosymmetric cluster analogues. This result can be attributed to the beneficial uniaxial magnetic dipolar coupling occurring in the chain-like nanocube assembly. Moreover, we could effectively synthesize enzymatically cleavable two-dimensional nanocube clusters, which upon exposure to a lytic enzyme, exhibit a progressive increase in magnetic particle imaging signal at well-defined incubation time points. The increase in magnetic particle imaging signal can be used to trace the disassembly of the large planar clusters into smaller nanocube chains by enzymatic polymer degradation. These studies demonstrate that chain-like assemblies of iron oxide nanocubes offer the best spatial arrangement to improve magnetic particle imaging signals. In addition, the nanocube clusters synthesized in this study also show remarkable transverse magnetic resonance imaging relaxation signals. These nanoprobes, previously showcased for their outstanding heat performance in magnetic hyperthermia applications, have great potential as dual imaging probes and could be employed to improve the tumor thermo-therapeutic efficacy, while offering a readable magnetic signal for image mapping of material disassemblies at tumor sites.

Stem cell and tissue regeneration analysis in low-dose irradiated planarians treated with cerium oxide nanoparticles.

Owing to the self-renewing reactive oxygen species scavenger capability of cerium oxide nanoparticles (nanoceria), we tested in vivo radioprotective effects on stem cells and tissue regeneration using low-dose irradiated planarians as model system. We treated planarians with nanoceria or gum Arabic, as control, and we analyzed the expression of stem cell molecular markers and tissue regeneration capability, as well as cell death and DNA damage in non-irradiated and in low-dose irradiated animals. Our findings show that nanoceria increase the number of stem cells and tissue regenerative capability, and reduce cell death and DNA damage after low-dose irradiation, suggesting a protective role on stem cells.

Novel synthesis of platinum complexes and their intracellular delivery to tumor cells by means of magnetic nanoparticles.

Platinum-based drugs are popular in clinics as chemotherapeutic agents to treat solid tumors. However, severe side effects such as nephro- and neurotoxicity impose strict dosage limitations that can lead to the development of drug resistance and tumor relapse. To overcome these issues Pt(iv) prodrugs and platinum delivery systems might represent the next generation of platinum-based drugs. In this study four novel Pt(ii) complexes (namely, PEG-Glu-Pt-EDA, PEG-Glu-Pt-DACH, PEG-Mal-Pt-EDA and PEG-Mal-Pt-DACH) were synthesized and a general strategy to covalently bind them to iron oxide nanoparticles was developed. The intracellular uptake and cell distribution studies of Pt-tethered magnetic nanoparticles on breast and ovarian cancer cell line models indicate that binding of the Pt complexes to the nanoparticles facilitates, for all the complexes, cellular internalization. Moreover, the magnetic nanoparticles (MNPs), as shown in a magnetofection experiment, enhance the uptake of MNP-Pt conjugates if a magnet is placed beneath the culture dish of tumor cells. As shown by a Pt release experiment, intranuclear platinum quantification and TEM analysis on cell sections, the presence of a pH-sensitive dicarboxylic group coordinating the Pt complex, triggers platinum dissociation from the NP surface. In addition, the triazole moiety facilitates endosomal swelling and the leakage of platinum from the endosomes with intranuclear localization of platinum release by the NPs. Finally, as assessed by MTT, caspase, calcein/ethidium bromide live/dead assays, among the four NP-Pt conjugates, the NP-Glu-Pt-EDA complex having a glutamate ring and ethylenediamine as a chelating amine group of the platinum showed higher cytotoxicity than the other three MNP-platinum conjugates.

Esterase-Cleavable 2D Assemblies of Magnetic Iron Oxide Nanocubes: Exploiting Enzymatic Polymer Disassembling To Improve Magnetic Hyperthermia Heat Losses.

Here, we report a nanoplatform based on iron oxide nanocubes (IONCs) coated with a bioresorbable polymer that, upon exposure to lytic enzymes, can be disassembled increasing the heat performances in comparison with the initial clusters. We have developed two-dimensional (2D) clusters by exploiting benchmark IONCs as heat mediators for magnetic hyperthermia and a polyhydroxyalkanoate (PHA) copolymer, a biodegradable polymer produced by bacteria that can be digested by intracellular esterase enzymes. The comparison of magnetic heat performance of the 2D assemblies with 3D centrosymmetrical assemblies or single IONCs emphasizes the benefit of the 2D assembly. Moreover, the heat losses of 2D assemblies dispersed in water are better than the 3D assemblies but worse than for single nanocubes. On the other hand, when the 2D magnetic beads (2D-MNBs) are incubated with the esterase enzyme at a physiological temperature, their magnetic heat performances began to progressively increase. After 2 h of incubation, specific absorption rate values of the 2D assembly double the ones of individually coated nanocubes. Such an increase can be mainly correlated to the splitting of the 2D-MNBs into smaller size clusters with a chain-like configuration containing few nanocubes. Moreover, 2D-MNBs exhibited nonvariable heat performances even after intentionally inducing their aggregation. Magnetophoresis measurements indicate a comparable response of 3D and 2D clusters to external magnets (0.3 T) that is by far faster than that of single nanocubes. This feature is crucial for a physical accumulation of magnetic materials in the presence of magnetic field gradients. This system is the first example of a nanoplatform that, upon exposure to lytic enzymes, such as those present in a tumor environment, can be disassembled from the initial 2D-MNB organization to chain-like assemblies with clear improvement of the heat magnetic losses resulting in better heat dissipation performances. The potential application of 2D nanoassemblies based on the cleavable PHAs for preserving their magnetic losses inside cells will benefit hyperthermia therapies mediated by magnetic nanoparticles under alternating magnetic fields.

Dually responsive gold-iron oxide heterodimers: merging stimuli-responsive surface properties with intrinsic inorganic material features.

We demonstrate a versatile approach for the preparation of dually responsive smart inorganic heterostructures (HSs) with the potential for exploitation in nanomedicine. We utilize Au-FexOy dimers as templates for generating smart inorganic HSs with a pH-responsive coating and a thermo-responsive coating attached to iron oxide and gold nanoparticles (NPs), respectively. First, a thiol-modified thermo-responsive (PNIPAAM-co-PEGA) polymer could be selectively attached to the gold domain by ligand exchange. The sequential attachment of a catechol-modified initiator to the iron oxide surface enables the in situ polymerization of a pH-responsive (PDMAEA) polymer. As hereby shown, the presence of the two distinct polymer domains on each NP subdomain enables each side of the HS to be loaded with different agents. Indeed, by a gel electrophoresis experiment we demonstrate the loading of siRNA on the pH-responsive polymer and the loading of Nile Blue dye, used as a drug model molecule, on the thermo-responsive polymer. The smart HSs exhibited good biocompatibility and downregulated GFP production when loaded with anti-GFP siRNA molecules. In addition, an investigation of the magnetic relaxivity times revealed that the high R2 relaxivity values of the HSs suggest their potential as contrast agents in magnetic resonance imaging (MRI) applications.

Facile transformation of FeO/Fe3O4 core-shell nanocubes to Fe3O4 via magnetic stimulation.

Here, we propose the use of magnetic hyperthermia as a means to trigger the oxidation of Fe1-xO/Fe3-δO4 core-shell nanocubes to Fe3-δO4 phase. As a first relevant consequence, the specific absorption rate (SAR) of the initial core-shell nanocubes doubles after exposure to 25 cycles of alternating magnetic field stimulation. The improved SAR value was attributed to a gradual transformation of the Fe1-xO core to Fe3-δO4, as evidenced by structural analysis including high resolution electron microscopy and Rietveld analysis of X-ray diffraction patterns. The magnetically oxidized nanocubes, having large and coherent Fe3-δO4 domains, reveal high saturation magnetization and behave superparamagnetically at room temperature. In comparison, the treatment of the same starting core-shell nanocubes by commonly used thermal annealing process renders a transformation to γ-Fe2O3. In contrast to other thermal annealing processes, the method here presented has the advantage of promoting the oxidation at a macroscopic temperature below 37 °C. Using this soft oxidation process, we demonstrate that biotin-functionalized core-shell nanocubes can undergo a mild self-oxidation transformation without losing their functional molecular binding activity.

Nanoparticles for inhibition of in vitro tumour angiogenesis: synergistic actions of ligand function and laser irradiation.

Careful design of nanoparticles plays a crucial role in their biomedical applications. It not only defines the stability of nanoparticles in a biological medium but also programs their biological functionality and specific interactions with cells. Here, an inorganic nanoparticulate system engineered to have a dual role as anti-angiogenic and hyperthermic agent is presented. The inorganic rod-shaped core is designed to strongly absorb near-infrared laser irradiation through the surface plasmon resonance and convert it into localized heat, while a peptide coating acts as an anti-angiogenic drug, altogether inhibiting vascular growth. The synergistic dual action provides an improved inhibition of the in vitro tumour angiogenesis, offering new possibilities for the development of nano-engineered anti-angiogenic drugs for therapies.

Targeting FR-expressing cells in ovarian cancer with Fab-functionalized nanoparticles: a full study to provide the proof of principle from in vitro to in vivo.

Efficient targeting in tumor therapies is still an open issue: systemic biodistribution and poor specific accumulation of drugs weaken efficacy of treatments. Engineered nanoparticles are expected to bring benefits by allowing specific delivery of drug to the tumor or acting themselves as localized therapeutic agents. In this study we have targeted epithelial ovarian cancer with inorganic nanoparticles conjugated to a human antibody fragment against the folate receptor over-expressed on cancer cells. The conjugation approach is generally applicable. Indeed several types of nanoparticles (either magnetic or fluorescent) were engineered with the fragment, and their biological activity was preserved as demonstrated by biochemical methods in vitro. In vivo studies with mice bearing orthotopic and subcutaneous tumors were performed. Elemental and histological analyses showed that the conjugated magnetic nanoparticles accumulated specifically and were retained at tumor sites longer than the non-conjugated nanoparticles.

Folate-grafted boron nitride nanotubes: possible exploitation in cancer therapy.

Boron nitride nanotubes (BNNTs) have generated considerable interest among the scientific community because of their unique physical and chemical properties. They present good chemical inertness, high thermal stability, and optimal resistance to oxidation, that make them ideal candidates for biomedical applications, in particular as nanovectors for drug, gene and protein delivery into the cells. In this study, BNNTs were prepared through a synthesis based on a chemical vapor deposition (CVD) method, and thereafter chemically functionalized with folic acid. The obtained nanostructures have been characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The characterization showed efficiently functionalized BNNTs of length of about 1 µm. Furthermore, confocal laser microscopy demonstrated that our nanotubes can be fluorescently-traced under appropriate excitation. Thanks to this property, it has been possible to investigate their internalization by HeLa cells through confocal microscopy, demonstrating that the BNNT up-take clearly increases after the functionalization with folate, a result confirmed by inductively coupled plasma (ICP) assessment of boron content inside the treated cell cultures.

In vivo biocompatibility of boron nitride nanotubes: effects on stem cell biology and tissue regeneration in planarians.

AIM: Boron nitride nanotubes (BNNTs) represent an extremely interesting class of nanomaterials, and recent findings have suggested a number of applications in the biomedical field. Anyhow, extensive biocompatibility investigations are mandatory before any further advancement toward preclinical testing. MATERIALS & METHODS: Here, we report on the effects of multiwalled BNNTs in freshwater planarians, one of the best-characterized in vivo models for developmental biology and regeneration research. RESULTS & DISCUSSION: Obtained results indicate that BNNTs are biocompatible in the investigated model, since they do not induce oxidative DNA damage and apoptosis, and do not show adverse effects on planarian stem cell biology and on de novo tissue regeneration. In summary, collected findings represent another important step toward BNNT realistic applications in nanomedicine.

One pot synthesis of monodisperse water soluble iron oxide nanocrystals with high values of the specific absorption rate.

We report a highly reproducible route to synthesize iron oxide nanoparticles (IONPs) with control over size and shape and with size dispersions around 10%. By tuning the relative ratio of squalane to dibenzyl ether, which were used as solvents in the synthesis, the size of the particles could be varied from 14 to around 100 nm, while their shape evolved from cubic (for size ranges up to 35 nm) to truncated octahedra and octahedra (for sizes from 40 nm up to 100 nm). Fine tuning of the size within each of these ranges could be achieved by varying the heating ramp and the iron precursor to decanoic acid ratio. We also demonstrate direct water transfer of the as-synthesized IONPs via in situ ligand exchange with gallol polyethylene glycol molecules, the latter simply added to the crude nanocrystal mixture at 70 °C. The specific absorption rate (SAR) values measured on the water transferred IONPs, at frequencies and applied magnetic fields that are considered safe for patients, confirmed their high heating performance. Finally, this method allows the transfer of 35 nm nanocubes as individually coated and stable particles to the water phase. For the first time, the heating performance of such large IONPs has been studied. This work uncovers the possibility of using large IONPs for magnetic hyperthermia in tumor therapy.

Biocompatibility of boron nitride nanotubes: an up-date of in vivo toxicological investigation.

Boron nitride nanotubes (BNNTs) represent an innovative and extremely intriguing class of nanomaterials, and preliminar but encouraging studies about their applications in biomedicine have emerged in the latest years. As a consequence, a systematic investigation of their biosafety has become of fundamental importance in the biomedical research. Extending our previous pilot in vivo study, here we present biocompatibility data of BNNTs injected in rabbits at a dose up to 10mg/kg. No significant adverse effects were found up to 7 days since their administration, and no impairments in blood, liver and kidney functionality were highlighted. Moreover, a terminal half-life circulation of about 90min was found. All the collected data are very promising, suggesting the optimal biocompatibility of BNNTs, and thus enabling their exploitation in nanomedicine as nanotransducers and nanocarriers.

Cytocompatibility evaluation of glycol-chitosan coated boron nitride nanotubes in human endothelial cells.

Boron nitride nanotubes (BNNTs) are intriguing nanomaterials with a wide range of potential biomedical applications. The assessment of BNNT interactions with biological systems, at both the cellular and subcellular levels, is an essential starting point for determining their bio-safety. We explore the effects of increasing concentrations of GC-BNNTs (0-100 µg/mL) on human vein endothelial cells (HUVECs), testing cell toxicity, proliferation, cytoskeleton integrity, cell activation and DNA damage. No significant changes were observed in cell viability, cytoskeleton integrity or DNA damage. Only a modest reduction in cell viability, tested by trypan blue assay, and the increased expression of vascular adhesion molecule-1, a marker of cell activation, were detected at the highest concentration used (100 µg/mL). Taken together, these findings indicate that GC-BNNTs do not affect endothelial cell biology, and are a promising first step in further investigation of their application potential in vascular targeting, imaging, and drug delivery.

GHz properties of magnetophoretically aligned iron-oxide nanoparticle doped polymers.

We show that assembled domains of magnetic iron-oxide nanoparticles (IONPs) are effective at increasing the dielectric permittivity of polydimethylsiloxane (PDMS) nanocomposites in the GHz frequency range. The assembly has been achieved by means of magnetophoretic transport and its efficacy, as well as the electromagnetic properties of the nanocomposite, has been found to depend on IONPs diameter. Remarkably, the dielectric permittivity increase has been obtained by keeping dielectric and magnetic losses very low, making us envision the suitability of nanocomposites based on aligned IONPs as substrates for radiofrequency applications.