Preparation of stable dispersion of barium titanate nanoparticles: Potential applications in biomedicine

Engineering 3D Scaffold-Free Nanoparticle-Laden Stem Cell Constructs for Piezoelectric Enhancement of Human Neural Tissue Formation and Function

Electrical stimulation (ES) of cellular systems can be utilized for biotechnological applications and electroceuticals (bioelectric medicine). Neural cell stimulation especially has a long history in neuroscience research and is increasingly applied for clinical therapies. Application of ES via conventional electrodes requires external connectors and power sources, hindering scientific and therapeutic applications. Here engineering novel 3D scaffold-free human neural stem cell constructs with integrated piezoelectric nanoparticles for enhanced neural tissue induction and function is described. Tetragonal barium titanate (BaTi03) nanoparticles are employed as piezoelectric stimulators prepared as cytocompatible dispersions, incorporated into 3D self-organizing neural spheroids, and activated wirelessly by ultrasound. Ultrasound delivery (low frequency; 40 kHz) is optimized for cell survival, and nanoparticle activation enabled ES throughout the spheroids during differentiation, tissue formation, and maturation. The resultant human neural tissues represent the first example of direct tissue loading with piezoelectric particles for ensuing 3D ultrasound-mediated piezoelectric enhancement of human neuronal induction from stem cells, including augmented neuritogenesis and synaptogenesis. It is anticipated that the platform described will facilitate advanced tissue engineering and in vitro modeling of human neural (and potentially non-neural) tissues, with modeling including tissue development and pathology, and applicable to preclinical testing and prototyping of both electroceuticals and pharmaceuticals.

Review on electrically conductive smart nerve guide conduit for peripheral nerve regeneration

At present, peripheral nerve injuries (PNIs) are one of the leading causes of substantial impairment around the globe. Complete recovery of nerve function after an injury is challenging. Currently, autologous nerve grafts are being used as a treatment; however, this has several downsides, for example, donor site morbidity, shortage of donor sites, loss of sensation, inflammation, and neuroma development. The most promising alternative is the development of a nerve guide conduit (NGC) to direct the restoration and renewal of neuronal axons from the proximal to the distal end to facilitate nerve regeneration and maximize sensory and functional recovery. Alternatively, the response of nerve cells to electrical stimulation (ES) has a substantial regenerative effect. The incorporation of electrically conductive biomaterials in the fabrication of smart NGCs facilitates the function of ES throughout the active proliferation state. This article overviews the potency of the various categories of electroactive smart biomaterials, including conductive and piezoelectric nanomaterials, piezoelectric polymers, and organic conductive polymers that researchers have employed latterly to fabricate smart NGCs and their potentiality in future clinical application. It also summarizes a comprehensive analysis of the recent research and advancements in the application of ES in the field of NGC.

Structural characterization, stability, and cytocompatibility study of chitosan BaTiO3@ZnO:Er heterostructures

New imaging agents are required in cancer diagnosis to enhance the diagnostic accuracy, classification, and therapeutic management of tumors. Nanomaterials have emerged as a promising alternative to developing new nanostructures with imaging applications. In this study, a heterostructure based on barium titanate (BT), zinc oxide (ZnO), and erbium (Er) was prepared and coated with Chitosan (CS) to investigate their stability and compatibility with biological systems. The structure, particle morphology, luminescence properties, stability, and cytotoxicity of different nanoparticles (NPs) were assessed. The results demonstrated the formation of a [BT@ZnO:Er]-CS heterostructure, which is consistent with the relative intensities and positions of peaks in the X-ray diffraction (XRD) with an average crystallite size of ~76 nm. The electrokinetic measurement results indicate that the coated NPs are the most stable and have an average size close to 200 nm when the pH is between 3 and 5. Finally, we presented a cytotoxicity study of naked and CS-coated NPs. The results indicate that naked NPs exhibit varying cellular toxicity, as indicated by decreased cell viability, morphological changes, and an increase in an apoptotic marker. The CS-coated NPs prevented the cytotoxic effect of the naked NPs, demonstrating the significance of CS as a stabilizing agent.

Piezoelectric nanocomposite bioink and ultrasound stimulation modulate early skeletal myogenesis

Despite the significant progress in bioprinting for skeletal muscle tissue engineering, new stimuli-responsive bioinks to boost the myogenesis process are highly desirable. In this work, we developed a printable alginate/Pluronic-based bioink including piezoelectric barium titanate nanoparticles (nominal diameter: ∼60 nm) for the 3D bioprinting of muscle cell-laden hydrogels. The aim was to investigate the effects of the combination of piezoelectric nanoparticles with ultrasound stimulation on early myogenic differentiation of the printed structures. After the characterization of nanoparticles and bioinks, viability tests were carried out to investigate three nanoparticle concentrations (100, 250, and 500 μg mL^-1) within the printed structures. An excellent cytocompatibility was confirmed for nanoparticle concentrations up to 250 μg mL^-1. TEM imaging demonstrated the internalization of BTNPs in intracellular vesicles. The combination of piezoelectric nanoparticles and ultrasound stimulation upregulated the expression of MYOD1, MYOG, and MYH2 and enhanced cell aggregation, which is a crucial step for myoblast fusion, and the presence of MYOG in the nuclei. These results suggest that the direct piezoelectric effect induced by ultrasound on the internalized piezoelectric nanoparticles boosts myogenesis in its early phases.

Neuron Compatibility and Antioxidant Activity of Barium Titanate and Lithium Niobate Nanoparticles

The biocompatibility and the antioxidant activity of barium titanate (BaTiO₃) and lithium niobate (LiNbO₃) were investigated on a neuronal cell line, the PC12, to explore the possibility of using piezoelectric nanoparticles in the treatment of inner ear diseases, avoiding damage to neurons, the most delicate and sensitive human cells. The cytocompatibility of the compounds was verified by analysing cell viability, cell morphology, apoptotic markers, oxidative stress and neurite outgrowth. The results showed that BaTiO₃ and LiNbO₃ nanoparticles do not affect the viability, morphological features, cytochrome c distribution and production of reactive oxygen species (ROS) by PC12 cells, and stimulate neurite branching. These data suggest the biocompatibility of BaTiO₃ and LiNbO₃ nanoparticles, and that they could be suitable candidates to improve the efficiency of new implantable hearing devices without damaging the neuronal cells.

Beta-Titanium Alloy Covered by Ferroelectric Coating–Physicochemical Properties and Human Osteoblast-Like Cell Response

Beta-titanium alloys are promising materials for bone implants due to their advantageous mechanical properties. For enhancing the interaction of bone cells with this perspective material, we developed a ferroelectric barium titanate (BaTiO3) coating on a Ti39Nb alloy by hydrothermal synthesis. This coating was analyzed by scanning electron and Raman microscopy, X-ray diffraction, piezoresponse force microscopy, X-ray photoelectron spectroscopy, nanoindentation, and roughness measurement. Leaching experiments in a saline solution revealed that Ba is released from the coating. A progressive decrease of Ba concentration in the material was also found after 1, 3, and 7 days of cultivation of human osteoblast-like Saos-2 cells. On day 1, the Saos-2 cells adhered on the BaTiO3 film in higher initial numbers than on the bare alloy, but they were less spread, and their initial proliferation rate was slower. These cells also contained a lower amount of beta1-integrins and vinculin, i.e., molecules involved in cell adhesion, and produced a lower amount of collagen I. This cell behavior was attributed to a higher surface roughness of BaTiO3 film rather than to its potential cytotoxicity, because the cell viability on this film was very high, reaching almost 99%. The amount of alkaline phosphatase, an enzyme involved in bone matrix mineralization, was similar in cells on the BaTiO3-coated and uncoated alloy, and on day 7, the cells on BaTiO3 film attained a higher final cell population density. These results indicate that after some improvements, particularly in its roughness and stability, the hydrothermal ferroelectric BaTiO3 film could be promising coating for improved osseointegration of bone implants.

Electroactive barium titanate coated titanium scaffold improves osteogenesis and osseointegration with low-intensity pulsed ultrasound for large segmental bone defects

For large segmental bone defects, porous titanium scaffolds have some advantages, however, they lack electrical activity which hinders their further use. In this study, a barium titanate (BaTiO3) piezoelectric ceramic was used to modify the surface of a porous Ti6Al4V scaffold (pTi), which was characterized by scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and roughness and water contact angle analyses. Low intensity pulsed ultrasound (LIPUS) was applied in vitro and in vivo study. The activity of bone marrow mesenchymal stem cells, including adhesion, proliferation, and gene expression, was significantly superior in the BaTiO3/pTi, pTi + LIPUS, and BaTiO3/pTi + LIPUS groups than in the pTi group. The activity was also higher in the BaTiO3/pTi + LIPUS group than in the BaTiO3/pTi and pTi + LIPUS groups. Additionally, micro-computed tomography, the mineral apposition rate, histomorphology, and the peak pull-out load showed that these scaffold conditions significantly enhanced osteogenesis and osseointegration 6 and 12 weeks after implantation in large segmental bone defects in the radius of rabbits compared with those resulting from the pTi condition. Consequently, the improved osteogenesis and osseointegration make the BaTiO3/pTi + LIPUS a promising method to promote bone regeneration in large segmental bone defects for clinical application.

Induction of osteogenic differentiation by demineralized and decellularized bovine extracellular matrix derived hydrogels associated with barium titanate

Bone tissue-derive biomaterials have become of great interest to treat diseases of the skeletal system. Biological scaffolds of demineralized and decellularized extracellular matrices (ECM) have been developed and one of these options are ECM hydrogels derived from bovine bone. Nanomaterials may be able to regulate stem cell differentiation due to their unique physical-chemical properties. The present work aimed to evaluate the osteoinductive effects of ECM hydrogels associated with barium titanate nanoparticles (BTNP) on dental pulp cells derived from exfoliated teeth. The addition of BTNP in the ECM derived hydrogel did not affect cell proliferation and the formation of bone nodules. Furthermore, it increased the expression of bone alkaline phosphatase. The results demonstrated that the nanobiocomposites were able to promote the osteogenic differentiation, even in the absence of chemical inducing factors for osteogenic differentiation. In conclusion, bovine bone ECM hydrogel combined with BTNP presented and increased expression of markers of osteogenic differentiation in the absence of chemical inducing factors.

Antibody-Conjugated Barium Titanate Nanoparticles for Cell-Specific Targeting

Barium titanate nanoparticles (BTNPs) are gaining popularity in biomedical research because of their piezoelectricity, nonlinear optical properties, and high biocompatibility. However, the potential of BTNPs is limited by the ability to create stable nanoparticle dispersions in water and physiological media. In this work, we report a method of surface modification of BTNPs based on surface hydroxylation followed by covalent attachment of hydrophilic poly(ethylene glycol) (PEG) polymers. This polymer coating allows for additional modifications such as fluorescent labeling, surface charge tuning, or directional conjugation of IgG antibodies. We demonstrate the conjugation of anti-EGFR antibodies to the BTNP surface and show efficient molecular targeting of the nanoparticles to A431 cells. Overall, the reported modifications aim to expand the BTNP applications in molecular imaging, cancer therapy, or noninvasive neurostimulation.

Barium Titanate Nanoparticles Sensitise Treatment-Resistant Breast Cancer Cells to the Antitumor Action of Tumour-Treating Fields

Although tumour-treating fields (TTFields) is a promising physical treatment modality based on disruption of dipole alignments and generation of dielectrophoretic forces during cytokinesis, not much is known about TTFields-responsive sensitisers. Here, we report a novel TTFields-responsive sensitiser, barium titanate nanoparticles (BTNPs), which exhibit cytocompatibility, with non-cytotoxic effects on breast cancer cells. BTNPs are characterised by high dielectric constant values and ferroelectric properties. Notably, we found that BTNPs sensitised TTFields-resistant breast cancer cells in response to TTFields. In addition, BTNPs accumulated in the cytoplasm of cancer cells in response to TTFields. Further, we showed that TTFields combined with BTNPs exhibited antitumor activity by modulating several cancer-related pathways in general, and the cell cycle-related apoptosis pathway in particular. Therefore, our data suggest that BTNPs increase the antitumor action of TTFields by an electric field-responsive cytosolic accumulation, establishing BTNP as a TTFields-responsive sensitiser.

Cryo-analytical STEM of frozen, aqueous dispersions of nanoparticles

In situ characterisation of nanoparticle dispersion and surface coatings is required to further our understanding of the behaviour of nanoparticles in aqueous suspension. Using cryogenic transmission electron microscopy (cryo-TEM) it is possible to analyse a nanoparticle suspension in the frozen, hydrated state; however, this analysis is often limited to imaging alone. This work demonstrates the first use of analytical scanning TEM (STEM) in the examination of nanoparticles captured in a layer of vitreous ice. Imaging and analysis of frozen hydrated suspensions by both STEM energy dispersive X-ray (EDX) spectroscopy and electron energy loss spectroscopy (EELS) under cryogenic conditions demonstrates the identification and separation of CeO₂, Fe₂O₃, ZnO and Ag nanoparticles in suspension. Damage caused by the electron beam was shown to occur at far higher electron fluences in STEM (<2000 e^-/Ų) compared to CTEM (<100 e^-/Ų) due to diffusion limited damage by the radiolysis products generated in vitreous ice. Further application of cryo-analytical STEM was undertaken on barium titanate biomarker nanoparticles dispersed in cell culture media to show the formation of a Ca and P rich coating around the nanoparticles when suspended in the media. This previously unreported coating changes the surface chemistry of the biomarkers when exposed to cells. Thus we show that the technique has the potential to advance our understanding of the fundamental behaviour of nanoparticles in complex aqueous suspensions.

Piezoelectric Effects of Materials on Bio-Interfaces

Electrical stimulation of cells and tissues is an important approach of interaction with living matter, which has been traditionally exploited in the clinical practice for a wide range of pathological conditions, in particular, related to excitable tissues. Standard methods of stimulation are, however, often invasive, being based on electrodes and wires used to carry current to the intended site. The possibility to achieve an indirect electrical stimulation, by means of piezoelectric materials, is therefore of outstanding interest for all the biomedical research, and it emerged in the latest decade as a most promising tool in many bioapplications. In this paper, we summarize the most recent achievements obtained by our group and by others in the exploitation of piezoelectric nanoparticles and nanocomposites for cell stimulation, describing the important implications that these studies present in nanomedicine and tissue engineering. A particular attention will be also dedicated to the physical modeling, which can be extremely useful in the description of the complex mechanisms involved in the mechanical/electrical transduction, yet also to gain new insights at the base of the observed phenomena.

Confocal imaging of single BaTiO3 nanoparticles by two-photon photothermal microscopy

We report on the development of a nonlinear optical microscopic technique based on two-photon absorption induced photothermal effect capable of detecting individual nonfluorescent nanoparticles with high sensitivity. The method which is inherently confocal makes use of near infrared excitation at high repetition rates and would be of interest in deep tissue imaging. We demonstrate the applicability of the technique by imaging single BaTiO₃ nanoparticles, a potential biomolecular label having high photostability, in a scattering environment at fast time scales with a pixel dwell time of 80 μs.

Structure and Rheology of Poloxamine T1107 and Its Nanocomposite Hydrogels with Cyclodextrin-Modified Barium Titanate Nanoparticles

We report the preparation of a nanocomposite hydrogel based on a poloxamine gel matrix (Tetronic T1107) and cyclodextrin (CD)-modified barium titanate (BT) nanoparticles. The micellization and sol-gel behavior of pH-responsive block copolymer T1107 were fully characterized by small-angle neutron scattering (SANS), dynamic light scattering (DLS), and Fourier transform infrared attenuated total reflectance (FTIR-ATR) spectroscopy as a function of concentration, pH and temperature. SANS results reveal that spherical micelles in the low concentration regime present a dehydrated core and highly hydrated shell, with a small aggregation number and size, highly dependent on the degree of protonation of the central amine spacer. At high concentration, T1107 undergoes a sol-gel transition, which is inhibited at acidic pH. Nanocomposites were prepared by incorporating CD-modified BT of two different sizes (50 and 200 nm) in concentrated polymer solutions. Rheological measurements show a broadening of the gel region, as well as an improvement of the mechanical properties, as assessed by the shear elastic modulus, G' (up to 200% increase). Initial cytocompatibility studies of the nanocomposites show that the materials are nontoxic with viabilities over 70% for NIH3T3 fibroblast cell lines. Overall, the combination of Tetronics and modified BaTiO3 provides easily customizable systems with promising applications as soft piezoelectric materials.

Barium titanate nanoparticles: promising multitasking vectors in nanomedicine

Ceramic materials based on perovskite-like oxides have traditionally been the object of intense interest for their applicability in electrical and electronic devices. Due to its high dielectric constant and piezoelectric features, barium titanate (BaTiO3) is probably one of the most studied compounds of this family. Recently, an increasing number of studies have been focused on the exploitation of barium titanate nanoparticles (BTNPs) in the biomedical field, owing to the high biocompatibility of BTNPs and their peculiar non-linear optical properties that have encouraged their use as nanocarriers for drug delivery and as label-free imaging probes. In this review, we summarize all the recent findings about these 'smart' nanoparticles, including the latest, most promising potential as nanotransducers for cell stimulation.

Size-dependent ecotoxicity of barium titanate particles: the case of Chlorella vulgaris green algae

Studies have been demonstrating that smaller particles can lead to unexpected and diverse ecotoxicological effects when compared to those caused by the bulk material. In this study, the chemical composition, size and shape, state of dispersion, and surface's charge, area and physicochemistry of micro (BT MP) and nano barium titanate (BT NP) were determined. Green algae Chlorella vulgaris grown in Bold's Basal (BB) medium or Seine River water (SRW) was used as biological indicator to assess their aquatic toxicology. Responses such as growth inhibition, cell viability, superoxide dismutase (SOD) activity, adenosine-5-triphosphate (ATP) content and photosynthetic activity were evaluated. Tetragonal BT (~170 nm, 3.24 m(2) g(-1) surface area) and cubic BT (~60 nm, 16.60 m(2) g(-1)) particles were negative, poorly dispersed, and readily aggregated. BT has a statistically significant effect on C. vulgaris growth since the lower concentration tested (1 ppm), what seems to be mediated by induced oxidative stress caused by the particles (increased SOD activity and decreased photosynthetic efficiency and intracellular ATP content). The toxic effects were more pronounced when the algae was grown in SRW. Size does not seem to be an issue influencing the toxicity in BT particles toxicity since micro- and nano-particles produced significant effects on algae growth.

Full determination of single ferroelectric nanocrystal orientation by Pockels electro-optic microscopy

We present a nanoscale electro-optic imaging method allowing access to the phase response, which is not amenable to classical second-harmonic generation microscopy. This approach is used to infer the vectorial orientation of single domain ferroelectric nanocrystals, based on polarization-resolved Pockels microscopy. The electro-optic phase response of KTP nanoparticles yields the full orientation in the laboratory frame of randomly dispersed single nanoparticles, together with their electric polarization dipole. The complete vector determination of the dipole orientation is a prerequisite to important applications including ferroelectric nanodomain orientation, membrane potential imaging, and rotational dynamics of single biomolecules.

Barium titanate nanoparticles and hypergravity stimulation improve differentiation of mesenchymal stem cells into osteoblasts

Background

Enhancement of the osteogenic potential of mesenchymal stem cells (MSCs) is highly desirable in the field of bone regeneration. This paper proposes a new approach for the improvement of osteogenesis combining hypergravity with osteoinductive nanoparticles (NPs).

Materials and methods

In this study, we aimed to investigate the combined effects of hypergravity and barium titanate NPs (BTNPs) on the osteogenic differentiation of rat MSCs, and the hypergravity effects on NP internalization. To obtain the hypergravity condition, we used a large-diameter centrifuge in the presence of a BTNP-doped culture medium. We analyzed cell morphology and NP internalization with immunofluorescent staining and coherent anti-Stokes Raman scattering, respectively. Moreover, cell differentiation was evaluated both at the gene level with quantitative real-time reverse-transcription polymerase chain reaction and at the protein level with Western blotting.

Results

Following a 20 g treatment, we found alterations in cytoskeleton conformation, cellular shape and morphology, as well as a significant increment of expression of osteoblastic markers both at the gene and protein levels, jointly pointing to a substantial increment of NP uptake. Taken together, our findings suggest a synergistic effect of hypergravity and BTNPs in the enhancement of the osteogenic differentiation of MSCs.

Conclusion

The obtained results could become useful in the design of new approaches in bone-tissue engineering, as well as for in vitro drug-delivery strategies where an increment of nanocarrier internalization could result in a higher drug uptake by cell and/or tissue constructs.

Ecotoxicological studies of micro- and nanosized barium titanate on aquatic photosynthetic microorganisms

The interaction between live organisms and micro- or nanosized materials has become a current focus in toxicology. As nanosized barium titanate has gained momentum lately in the medical field, the aims of the present work are: (i) to assess BT toxicity and its mechanisms on the aquatic environment, using two photosynthetic organisms (Anabaena flos-aquae, a colonial cyanobacteria, and Euglena gracilis, a flagellated euglenoid); (ii) to study and correlate the physicochemical properties of BT with its toxic profile; (iii) to compare the BT behavior (and Ba(2+) released ions) and the toxic profile in synthetic (Bold's Basal, BB, or Mineral Medium, MM) and natural culture media (Seine River Water, SRW); and (iv) to address whether size (micro, BT MP, or nano, BT NP) is an issue in BT particles toxicity. Responses such as growth inhibition, cell viability, superoxide dismutase (SOD) activity, adenosine-5-triphosphate (ATP) content and photosynthetic efficiency were evaluated. The main conclusions are: (i) BT have statistically significant toxic effects on E. gracilis growth and viability even in small concentrations (1μgmL(-1)), for both media and since the first 24 h; on the contrary of on A. flos-aquae, to whom the effects were noticeable only for the higher concentrations (after 96 h: ≥75 μg mL(-1) for BT NP and =100 μg mL(-1) for BT MP, in BB; and ≥75 μg mL(-1) for both materials in SRW), in spite of the viability being affected in all concentrations; (ii) the BT behaviors in synthetic and natural culture media were slightly different, being the toxic effects more pronounced when grown in SRW - in this case, a worse physiological state of the organisms in SRW can occur and account for the lower resistance, probably linked to a paucity of nutrients or even a synergistic effect with a contaminant from the river; and (iii) the effects seem to be mediated by induced stress without a direct contact in A. flos-aquae and by direct endocytosis in E. gracilis, but in both organisms the contact with both BT MP and BT NP increased SOD activity and decreased photosynthetic efficiency and intracellular ATP content; and (iv) size does not seem to be an issue in BT particles toxicity since micro- and nano-particles produced significant toxic for the model-organisms.

Coating barium titanate nanoparticles with polyethylenimine improves cellular uptake and allows for coupled imaging and gene delivery

Barium titanate nanoparticles (BT NP) belong to a class of second harmonic generating (SHG) nanoprobes that have recently demonstrated promise in biological imaging. Unfortunately, BT NPs display low cellular uptake efficiencies, which may be a problem if cellular internalization is desired or required for a particular application. To overcome this issue, while concomitantly developing a particle platform that can also deliver nucleic acids into cells, we coated the BT NPs with the cationic polymer polyethylenimine (PEI)-one of the most effective nonviral gene delivery agents. Coating of BT with PEI yielded complexes with positive zeta potentials and resulted in an 8-fold increase in cellular uptake of the BT NPs. Importantly, we were able to achieve high levels of gene delivery with the BT-PEI/DNA complexes, supporting further efforts to generate BT platforms for coupled imaging and gene therapy.

Barium titanate core--gold shell nanoparticles for hyperthermia treatments

The development of new tools and devices to aid in treating cancer is a hot topic in biomedical research. The practice of using heat (hyperthermia) to treat cancerous lesions has a long history dating back to ancient Greece. With deeper knowledge of the factors that cause cancer and the transmissive window of cells and tissues in the near-infrared region of the electromagnetic spectrum, hyperthermia applications have been able to incorporate the use of lasers. Photothermal therapy has been introduced as a selective and noninvasive treatment for cancer, in which exogenous photothermal agents are exploited to achieve the selective destruction of cancer cells. In this manuscript, we propose applications of barium titanate core–gold shell nanoparticles for hyperthermia treatment against cancer cells. We explored the effect of increasing concentrations of these nanoshells (0–100 μg/mL) on human neuroblastoma SH-SY5Y cells, testing the internalization and intrinsic toxicity and validating the hyperthermic functionality of the particles through near infrared (NIR) laser-induced thermoablation experiments. No significant changes were observed in cell viability up to nanoparticle concentrations of 50 μg/mL. Experiments upon stimulation with an NIR laser revealed the ability of the nanoshells to destroy human neuroblastoma cells. On the basis of these findings, barium titanate core–gold shell nanoparticles resulted in being suitable for hyperthermia treatment, and our results represent a promising first step for subsequent investigations on their applicability in clinical practice.

Effects of barium titanate nanoparticles on proliferation and differentiation of rat mesenchymal stem cells

Nanomaterials hold great promise in the manipulation and treatments of mesenchymal stem cells, since they allow the modulation of their properties and differentiation. However, systematic studies have to be carried out in order to assess their potential toxicological effects. The present study reports on biocompatibility evaluation of glycol-chitosan coated barium titanate nanoparticles (BTNPs) on rat mesenchymal stem cells (MSCs). BTNPs are a class of ceramic systems which possess interesting features for biological applications thanks to their peculiar dielectric and piezoelectric properties. Viability was evaluated up to 5 days of incubation (concentrations in the range 0-100 μg/ml) both quantitatively and qualitatively with specific assays. Interactions cells/nanoparticles were further investigated with analysis of the cytoskeleton conformation, with SEM and TEM imaging, and with AFM analysis. Finally, differentiation in adipocytes and osteocytes was achieved in the presence of high doses of BTNPs, thus highlighting the safety of these nanostructures towards mesenchymal stem cells.

Imaging with second-harmonic radiation probes in living tissue

We demonstrate that second-harmonic radiation imaging probes are efficient biomarkers for imaging in living tissue. We show that 100 nm and 300 nm BaTiO(3) nanoparticles used as contrast markers could be detected through 50 μm and 120 μm of mouse tail tissue in vitro or in vivo. Experimental results and Monte-Carlo simulations are in good agreement.

Barium Titanate Nanoparticles: Highly Cytocompatible Dispersions in Glycol-chitosan and Doxorubicin Complexes for Cancer Therapy

In the latest years, innovative nanomaterials have attracted a dramatic and exponentially increasing interest, in particular for their potential applications in the biomedical field. In this paper, we reported our findings on the cytocompatibility of barium titanate nanoparticles (BTNPs), an extremely interesting ceramic material. A rational and systematic study of BTNP cytocompatibility was performed, using a dispersion method based on a non-covalent binding to glycol-chitosan, which demonstrated the optimal cytocompatibility of this nanomaterial even at high concentration (100 μg/ml). Moreover, we showed that the efficiency of doxorubicin, a widely used chemotherapy drug, is highly enhanced following the complexation with BTNPs. Our results suggest that innovative ceramic nanomaterials such as BTNPs can be realistically exploited as alternative cellular nanovectors.