Publications

The aggressive scaling of electronic devices has brought ferroelectric materials to the forefront of nanoscale research, where lateral dimensions strongly influence switching dynamics and device performance. In this context, W/ Hf0.5Zr0.5O2/ p-Ge capacitors with top electrode sizes ranging from 10 & micro;m down to 0.1 & micro;m are investigated using conductive atomic force microscopy (C-AFM). Frequency-dependent measurements reveal that peak switching currents (Isw) increase with sweep rate, yet the total switched charge remains nearly constant, consistent with full polarization reversal in micro- and submicron devices. Positive-Up-Negative-Down (PUND) analysis further isolates the switching current, allowing reconstruction of polarization-voltage (P--V) loops and quantification of remnant polarization. The smallest devices (0.01 & micro;m2) exhibit switching currents below the detection threshold due to parasitic capacitance, masking intrinsic ferroelectric behavior. In contrast, submicron capacitors display an apparent increase of remanent polarization attributed to the larger perimeter-to-area ratio, emphasizing the role of edge-dominated switching. Together, these findings establish C-AFM as a powerful, spatially resolved technique for probing ferroelectric switching in realistic device geometries, providing essential insights for non-volatile memory and neuromorphic applications.

Copper-doped hydroxyapatite (5CuHAp) coatings were obtained using the dip-coating technique and comprehensively characterized for structural, surface, and biological performance. X-ray diffraction confirmed phasepure hydroxyapatite with minimal Cu-induced lattice distortion. XPS revealed Cu2+ incorporation at 4.8 at. % and surface (Ca + Cu)/P ratio of 1.67. SEM and multiscale AFM showed homogeneous, crack-free coatings with hierarchical nanoscale features; maximum furrow depths ranged 0.022-0.65 mu m across MG63 incubation times, with fractal dimensions 2.44-2.57 and high directional anisotropy. Slope and frequency analyses indicated dominant surface orientations and multiscale periodicity (lambda = 7.1 mu m; phase 86-150 degrees). In vitro MG63 assays demonstrated rapid adhesion, spreading, and proliferation, correlating with nanoscale guidance cues and surface energy landscape. These findings establish adapted sol-gel 5CuHAp coatings as structurally coherent, bioactive, and osteoconductive substrates, offering precise nanoscale topography and compositional control for orthopedic and dental implant applications. The in vitro biocompatibility of the 5CuHAp coatings was evaluated using MG63 human osteosarcoma cells through complementary MTT and LDH assays. The MTT studies revealed high cell viability after 24, 48, and 72 h of exposure, indicating good cytocompatibility and the absence of significant inhibitory effects on the cell viability or proliferation. Furthermore, the LDH assay revealed low levels of enzyme release into the culture medium relative to control cells, suggesting minimal membrane damage and limited cytotoxic effects. Together, these results highlight that the 5CuHAp coatings exhibit favorable biological behavior and support their potential suitability for biomedical applications.

In this manuscript we report the development of magnesium doped hydroxyapatite in chitosan matrix (5HMC_0, Ca10 -xMgx(PO4)(6)(OH)(2), with x(Mg) = 0.05) by adapted sol-gel method. Then, the 5HMC_0 composite layers were developed using dip-coating technique. The obtained composite layers were exposed to Dulbecco's Modified Eagle Medium (DMEM) for 7 and 14 days. Then, the 5HMC samples were thoroughly analyzed both before and after immersion in DMEM for 7 and 14 days in order to investigate the structural and compositional changes induced by the DMEM environment. To perform a comprehensive evaluation, multiple characterization techniques were used, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). To investigate the chemical composition, bonding states, and surface characteristics of the 5HMC_0, 5HMC_7, and 5HMC_14 samples, X-ray photoelectron spectroscopy (XPS) analyses were performed. XPS provides detailed insight into the chemical transformations occurring at the composite surface. These methods provided detailed information on the surface morphology and chemical composition, of the 5HMC samples (before and after immersion in DMEM). FTIR analysis of 5HMC confirmed the presence of characteristic phosphate and amide bands at similar to 1043 cm(-)& sup1; and similar to 1650 cm(-)& sup1; , while AFM measurements revealed a surface roughness (Ra) of approximately 68.46 nm (for the 5HMC sample); SEM studies indicated a homogeneous, crack-free morphology (for the 5HMC sample), and XPS and EDS analysis showed the Mg incorporation in the 5HMC composite layers. The biological properties of 5HMC layers were evaluated before and after immersion in DMEM medium with the aid of HGF-1 cell line (ATCC CRL-2014). The cell viability assay MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) showed that the 5HMC layers supported the proliferation of the fibroblast cells on their surface (having a cell viability above 94%). More than that, this preliminary study highlights the importance of 5HMC layers, demonstrating their favorable physicochemical and biological characteristics after exposure to DMEM, supporting their potential suitability for applications in bone implants, as well as in the orthopedic and dental fields.

We present experimental results on VO2, which is the most utilized Mott material, grown by atomic layer deposition on single-crystalline Si (100) (VO2/Si) wafers and followed by thermal treatment at 500 degrees C for different times: 30, 60 and 90 min. All these structures have shown in-plane ferroelectricity, the best results being obtained for VO2 treated thermically at 500 degrees C during 60 min. The remanent polarization in this case is 100 mu C cm-2 at room temperature at coercive voltages +/- 10 V. Current-voltage and polarization-voltage dependences at various temperatures have shown that VO2 has a reversible insulator-metal transition at 66 degrees C.

Erythropoietin (EPO), a glycoprotein hormone conventionally associated with erythropoiesis, has emerged as a versatile macromolecule with substantial therapeutic potential in tissue engineering and regenerative medicine. Beyond its role in red blood cell production, EPO displays pleiotropic effects, including angiogenesis, neuroprotection, anti-apoptosis, immunomodulation, and cell survival, making it a suitable agent for tissue repair and regeneration. This review explores EPO's biological characteristics and its integration into tissue-engineered constructs through innovative approaches such as scaffold immobilization, hydrogel encapsulation, and genetically modified cells for localized delivery. EPO has shown remarkable efficacy in regenerating diverse tissues, including bone, cartilage, neural, cardiac, dental, and skin, and in promoting wound healing. Additionally, its applications extend to advanced fields such as organoid development, immune modulation, and cancer research, further highlighting its versatility. Nevertheless, challenges such as maintaining EPO's bioactivity, achieving controlled and sustained delivery, and mitigating systemic or off-target effects remain significant barriers. Furthermore, its dual role in cancer biology necessitates a deeper understanding of its effects on tumor growth and immunity. Future advances in biomaterials and precision medicine could optimize EPO-based delivery systems to enable personalized therapeutic solutions. EPO stands poised to revolutionize tissue engineering, thus bridging laboratory innovation and clinical applications.

Efficient recycling of polypropylene (PP) from complex waste streams remains a significant challenge, particularly for multilayer non-woven materials. Here, we report a rapid dissolution-reprecipitation process for polypropylene recovery using a tailored ionic liquid formed from tris(2-ethylhexyl)amine and 3,3-dimethylbutyric acid. The process operates at 160 degrees C under ambient pressure, achieving up to 99% polymer recovery, with complete dissolution occurring in less than one minute. An integrated hot filtration step simultaneously removes pigments and additives, eliminating the need for additional purification stages. The recovered polymer exhibits thermal, structural, and mechanical properties comparable to virgin polypropylene, confirming preservation of polymer integrity. Quasi-elastic neutron scattering (QENS) provides molecular-level insight into the dissolution mechanism, revealing enhanced polymer mobility and plasticisation induced by the ionic liquid. Complementary spectroscopic and chromatographic analyses confirm the chemical stability of the solvent across the investigated temperature range, supporting its potential for reuse. This work establishes a mechanistically informed, solvent-based strategy for polypropylene recycling, offering a scalable pathway for recovering polyolefins from complex waste streams.

Functionalized gold nanoparticles (AuNPs) have emerged as versatile platforms in therapeutic research, yet their specific roles in regenerative medicine, particularly in modulating prokaryotic and eukaryotic cell responses, enhancing antioxidant defense, and supporting tissue repair mechanisms, remain insufficiently elucidated. In this study, we have obtained gold nanoparticles initially functionalized with the well-established antioxidant lipoic acid and subsequently with thiosalicylic acid. Their final modification with the 6-amino-chromen-2-one, a coumarin derivative with recognized antioxidant and pharmacological relevance, generated novel composite systems, distinguished by enhanced biological performance. The novel structures have been comprehensively characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (IR), and thermal analysis. Their biological properties were evaluated through antimicrobial and anti-adherence assays against standard and clinical strains, as well as antioxidant and biocompatibility (hemolytic/anti-hemolytic/cytotoxicity) assays. The findings highlight the strong therapeutic potential of functionalized AuNPs, demonstrating enhanced antimicrobial efficacy, antioxidant protection, and cytocompatibility. Their capacity to reduce oxidative stress and combat microbial infections show promise for advanced biomedical applications, such as controlled drug delivery and tissue regeneration.

Rapidly solidified Fe-Pd-based ferromagnetic shape memory alloy ribbons, modified with Mn or Ga additions, were produced and subjected to post-solidification heat treatments of varying duration to investigate the interplay between composition, surface characteristics, and functional properties. Surface morphology and wettability were evaluated alongside corrosion behavior, magnetic response, martensitic transformation, and in vitro cell adhesion. Corrosion performance was assessed through immersion and electrochemical techniques, providing insight into degradation kinetics. The results reveal a complex coupling between surface properties, corrosion resistance, and cell adhesion responses. Binary Fe-Pd ribbons exhibit moderately rough, homogeneous surfaces with stable Wenzel-type wetting, but limited electrochemical stability due to the reactivity of iron. Mncontaining ribbons display heterogeneous surface features and locally poor wettability after short heat treatments, leading to reduced corrosion resistance and degradation of magnetic and martensitic properties; nevertheless, they support favorable fibroblast adhesion. Prolonged annealing improves surface uniformity and wettability, while maintaining moderate corrosion resistance and good cell adhesion. Ga-containing ribbons show highly nonuniform topography combined with good hydrophilicity and the highest corrosion resistance, attributed to the formation of stable Ga-O protective products. Although corrosion effects are mitigated, partial suppression of magnetic and martensitic responses is observed. The findings highlight the potential of Fe-Pdbased ferromagnetic shape memory alloy ribbons as degradable biomedical substrates.

Developing magnetic nanocomposites (NCPs) based on magnetite (Fe3O4) and cerium dioxide (CeO2) nano-particles can be a beneficial solution to obtain multifunctional nanomaterials with pronounced bioactivity, which are promising for use in biomedical fields. In this study, we demonstrate that the synthesis conditions directly determine the morphology and surface chemical state of Fe3O4@CeO2 NCPs, and consequently the balance of Fe2+/Fe3+ and Ce3+/Ce4+ redox couples, which is crucial for their bioactivity. Controlled synthesis enables the formation of nanocomposites with a uniform CeO2 shell, optimized redox balance, and enhanced structural homogeneity compared to composites obtained via conventional precipitation methods. Experimental data confirmed that the morphology and surface chemical state directly influence the nanozymatic and anti-amyloid activities of the NCPs. The bioactivity of Fe3O4@CeO2 significantly exceeds that of individual Fe3O4 and CeO2 nanoparticles, indicating a synergistic effect arising from the balanced participation of both redox couples in biocatalytic processes. Furthermore, a potential mechanism for the synergistic enhancement of bioactivity is proposed, in which the Fe2+/Fe3+ and Ce3+/Ce4+ couples actively interact at the nanocomposite surface, enhancing redox processes and increasing the efficiency of antioxidant and anti-amyloid actions. The synthesized Fe2+/Fe3+ and Ce3+/Ce4+ nanocomposites also retain the ability to heat effectively under an alternating magnetic field, further boosting their biomedical potential. Overall, this work highlights that the choice of synthesis conditions is a key factor in controlling morphology, redox balance, and synergistic bioactivity of Fe3O4@CeO2 NCPs, opening new opportunities for the rational design of multifunctional bioactive nanomaterials.

Carbon-based nanomaterials (CBNs), including carbon nanotubes (CNTs), fullerenes, and graphene (GN), have attracted significant attention due to their unique structural, electrical, mechanical, and biocompatible properties. Their high surface area, excellent biocompatibility, and tunable physicochemical characteristics enable a wide range of applications, particularly in biomedicine, electronics, energy storage, and optoelectronics. CNTs, with their tensile strength and electrical conductivity, have been extensively studied for tissue engineering, drug delivery, and supercapacitor electrode applications. Despite concerns over their biocompatibility and toxicity, surface functionalization has shown promise in improving their performance and safety. Similarly, fullerenes, owing to their closed-cage structures and high electron affinity, exhibit potent antioxidant and photodynamic therapy capabilities, making them suitable for cancer treatment and optoelectronic devices. GN's high surface area and charge mobility make it ideal for energy storage systems such as supercapacitors and lithium-ion batteries, although its agglomeration tendency limits its practical use unless modified. This work provides a narrative synthesis of recent advancements and practical limitations, outlining future directions for biomedical and technological applications.