National Institute Of Materials Physics - Romania

Background: Hepatocellular carcinoma is associated with high mortality and increasing incidence. Sorafenib, a cornerstone of therapy for advanced hepatocellular carcinoma, presents certain disadvantages, including low bioavailability and poor water solubility. This work describes a new strategy for sorafenib-targeted delivery aimed at improving treatment efficiency and reducing side effects. Methods: Magnetic nanoparticles coated with azelaic acid were modified with aptamer molecules that specifically recognize human liver cancer cell line HepG2, ensuring specificity for the tumor tissue. The nanoparticles were further loaded with sorafenib. The obtained drug delivery system was extensively characterized using UV-Vis spectrophotometry, transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. Results: The drug delivery system demonstrated a higher release of sorafenib at acidic pH compared to pH 7.4. The cell internalization of the bare and aptamer-modified magnetic nanoparticles was assessed in HepG2 and human normal foreskin fibroblasts BJ cell lines, demonstrating that the aptamer significantly enhances internalization in tumor cells, while having no impact on healthy cells. Conclusions: The sorafenib-modified nanoparticles exhibited excellent cytocompatibility with BJ cells across all tested concentrations, while showing cytotoxicity towards HepG2 cells at higher concentrations, confirming the selectivity of the system.

Superoxide plays a significant role in maintaining physiological states of living systems, with major roles in eradicating invading microorganisms and in cell signaling. It is regulated intricately by the enzyme superoxide dismutase (SOD), and when not properly regulated it can lead to cascade biological pathways with severe and irreversible damage to biofilms, tissue, and organs, being linked with many neurodegenerative diseases, atherosclerotic and cardiovascular diseases. Therefore, superoxide anion (O center dot-2 ) detection has a tremendous potential in clinical diagnostics to assess oxidative stress in living cells. This comprehensive review aims to explore, discuss, and analyze recent trends in the electrochemical detection of O center dot-2 in living systems, focusing not only on the recognition mechanism for in vitro assays (living cell cultures/tissues) but also on the importance of the electrode design and operational parameters for in vivo measurements (implantable sensors). By analyzing current in vitro/in vivo electrochemical strategies we gather information that is helpful to overcome existing limitations in the dynamic monitoring of O center dot-2 , and further improve electrochemical strategies that can be adopted and applied to prevent its negative effect, with an insight into the pathophysiology of neurodegenerative disorders and even cellular malignancies that derive from its accumulation in living systems.

Chromium-doped hydroxyapatite (7CrHAp) and chromium-doped hydroxyapatite in chitosan matrix (7CrHAp-CH) coatings were synthesized in order to address the need for biomaterials with improved physico-chemical and biological properties for biomedical applications. Both chromium-doped hydroxyapatite (7CrHAp) and chromium-doped hydroxyapatite in chitosan matrix (7CrHAp-CH) coatings could represent promising materials for biomedical applications due to their superior properties. This study aims to evaluate the physico-chemical and in vitro biological properties of 7CrHAp and 7CrHAp-CH coatings to determine the impact of chitosan incorporation on the physico-chemical and biological features. The results reported in this study indicate that addition of chitosan improves surface uniformity and biological properties, highlighting their potential for uses in biomedical applications. In this study, coatings of chromium-doped hydroxyapatite (7CrHAp, with xCr = 0.07) and its composite variant embedded in a chitosan matrix (7CrHAp-CH) were systematically analyzed using a suite of characterization techniques: X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and metallographic microscopy (MM). The results of the XRD analysis revealed that the average crystal size was 19.63 nm for 7CrHAp and 16.29 nm for 7CrHAp-CH, indicating a decrease in crystallite size upon CH incorporation. The films were synthesized via the dip coating method using stable suspensions, whose stability was assessed through ultrasonic measurements (double-distilled water serving as the reference medium). The values obtained for the stability parameter were 2.5910-6 s-1 for 7CrHAp, 8.6410-7 s-1 for 7CrHAp-CH, and 3.1410-7 s-1 for chitosan (CH). These data underline that all samples are stable: CH is extremely stable, followed by 7CrHAp-CH (very stable) and 7CrHAp (stable). The in vitro biocompatibility of the 7CrHAp and 7CrHAp-CH coatings was evaluated with the aid of the MG63 cell line. The cytotoxic potential of these coatings towards MG63 cells was quantified using the MTT assay after 24 and 48 h of incubation. Our results highlight that both 7CrHAp and 7CrHAp-CH coatings exhibit high biocompatibility with MG63 cells, maintaining cell viability above 90% at both incubation times, thus supporting osteoblast-like cell proliferation. Furthermore, the antimicrobial efficacy of both 7CrHAp and 7CrHAp-CH samples was evaluated in vitro against the Pseudomonas aeruginosa 27853 ATCC (P. aeruginosa) reference strain. The in vitro antibacterial activity of the 7CrHAp and 7CrHAp-CH coatings was further evaluated against Pseudomonas aeruginosa 27853 ATCC (P. aeruginosa), Escherichia coli ATCC 25922 (E. coli) and Staphylococcus aureus ATCC 25923 (S. aureus) reference strains. In addition, atomic force microscopy (AFM) analysis was also used to investigate the ability of P. aeruginosa, E. coli and S. aureus cells to adhere and to develop colonies on the surfaces of the 7CrHAp and 7CrHAp-CH coatings. The results from the biological assays indicate that both coatings exhibit promising antibacterial properties, highlighting their potential for being used in biomedical applications, particularly in the development of novel antimicrobial devices.

The rapid growth of the global population has increased the need for efficient fabrication methods and materials to purify polluted water. In this study, we report the fabrication and characterization of reusable and efficient three-dimensional (3D) polydimethylsiloxane (PDMS) sponge composites designed for water treatment applications. By varying the ratios (10/90, 30/70, and 50/50) of large and small sacrificial templates' particles used in the fabrication method, we tailored the sponge's morphology and the interconnected pores' distribution. To achieve an enhanced photocatalytic activity, we incorporated titanium dioxide (TiO2) at different concentrations (1 % TiO2, 5 % TiO2, and 10 % TiO2 w/w) into the PDMS matrix. Scanning electron microscopy (SEM) was used to evaluate the structure of both 3D PDMS and TiO2@PDMS sponges, while energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD) confirmed the successful incorporation of TiO2 into the sponge framework. The photocatalytic performance of the 3D TiO2@PDMS composites was assessed by monitoring the degradation of Rhodamine B (RhB) under solar light irradiation, and the results were compared to those obtained using reference (TiO2-free) sponges under identical conditions. Very low Ti leaching effect have been evidenced by using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The reusability of the sponges was demonstrated through complete bleaching of the 554 nm RhB absorption band after four consecutive degradation cycles.

Composite x-at.% Yb:Y2O3/y-at.% Yb:Y2O3 (x = 0, 3, 5; y = 3, 5, 8) transparent ceramics with a graded doping profile of Yb3+ ions were obtained by solid-state reaction and multi-step sintering method. The multilayer ceramic compositions, consisting of two- and three-layers, were prepared by direct dry pressing of the constituent powders. Phase identification revealed that all sintered ceramics are well crystallized with a cubic structure similar to pure Y2O3, without impurity phases. Microstructural investigations have shown that the composite ceramics have a uniform morphology, with an average grain size of approximately 20 mu m, indicating that increasing the concentration of Yb3+ ions in the corresponding layers has no visible effect on the microstructure of the Y2O3 ceramics. Yb cations diffusion across the contact boundaries was investigated by the Energy Dispersive X-ray Spectroscopy analysis. Laser emission at 1.03 mu m was obtained from all ceramic samples, using quasi-continuous pumping at 971 nm with a fiber-coupled diode laser. This technique can be used to obtain multilayer ceramic structures, which could ensure for high-power lasers a controlled profile of the power absorbed in the active medium, or an efficient transfer of the heat generated during laser emission.

Overexpression of pyruvate kinase (PyK) is linked to many kinds of malignant tumors, representing therefore one of the most promising therapeutic targets for cancer treatment. Inhibition of PyK slows down tumor growth or causes tumor cell death, minimizing cancer cell proliferation, and understanding inhibitor mechanism of action can significantly improve cancer therapy. The present work describes the use of an amperometric bienzymatic biosensor, based on PyK and pyruvate oxidase (PyOx), in enzyme inhibition studies of four kinase inhibitors, CPG77675, Nilotinib, Ruxolitinib, Cerdulatinib. Their inhibition mechanism is studied and discussed in detail, with a thorough evaluation of their enzyme-inhibitor complex binding constants (Ki) and the inhibitor concentration required for 50% inhibition (IC50), employing standard inhibition procedure graphical methods. The biosensor is successfully applied for the quantification of the inhibitors by fixed potential amperometry, with excellent detection limit values in the pM range. It is the first detection method reported for the anticancer drugs CPG77675 and Cerdulatinib. The electrochemical assay based on the biosensor brings several advantages over the available assay kits for high-throughput screening (HTS) of kinase inhibitors, namely: low cost, easy operability and robustness demonstrated by biosensor high reproducibility and both operational and storage stability, offering an opportunity to discover new inhibitors and optimize their therapeutic index.

We report the synthesis and characterization of folic acid (FA)-conjugated human serum albumin nanoparticles, (HSA-FA):Ru NPs, as targeted carriers for rutin (Ru), a flavonoid with known anticancer activity. Nanoparticles were fabricated via a desolvation method, and their surface was functionalized with folic acid to promote selective uptake by cancer cells overexpressing folate receptors. Morphological and dimensional analyses performed by atomic force microscopy (AFM), scanning electron microscopy (SEM), and fluorescence microscopy confirmed that all nanoparticles were below 100 nm and exhibited good colloidal stability. Voltametric measurements confirmed the successful incorporation of both rutin and folic acid within the (HSA-FA):Ru nanoparticle formulation. Biological evaluation was conducted on healthy L929 fibroblasts and HT-29 colon adenocarcinoma cells. MTS colorimetric assays revealed that (HSA-FA):Ru NPs significantly reduced the viability of HT-29 cells, while maintaining higher compatibility with L929 cells. Fluorescence and electron microscopy further confirmed preferential nanoparticle uptake and surface accumulation in HT-29 cells, supporting the role of folic acid in enhancing targeted delivery. The study demonstrates that HSA-based nanoparticles functionalized with FA and loaded with Ru offer a biocompatible and efficient strategy for selective intracellular drug delivery in colorectal cancer. These findings support the use of albumin-based nanocarriers in the development of targeted therapeutic platforms for cancer treatment.

Due to the importance of buffer layers in interface engineering, the development of more variants and the rational design of materials have a significant influence on the performance of optoelectronic devices. This study provides a strategy to increase device performance by facilitating efficient charge transfer and defect passivation by combining the properties of eco-friendly materials (adenine, cytosine, guanine, thymine, and uracil) with the physicochemical properties of metal oxides. The aim of this paper was to investigate the interaction of zinc oxide (ZnO) nanostructures (seed, nanoparticles, and nanowires) with nucleobase layers and to discuss their potential applications as organic-inorganic interfacial bilayers. The impact is analyzed from structural, morphological, optical, and electrical points of view. Nucleobase-ZnO nanostructure layers present high optical transparency in the visible range. Electrical measurements confirmed that the high surface area of nanowires can enhance interactions with nucleobases, leading to better charge transfer. The results showed that these nucleobase-ZnO nanostructure layers are promising interface materials for enhancing optoelectronic device performance through interfacial charge transport and light management, while enabling the design of environmentally friendly devices.

Paper-based devices hold great promise in biosensing, but the choice of electrode materials influences performance. Here, we report a paper-based electrochemical sensor developed for nucleic acid quantification, in a sandwich-type architecture integrating 3-electrode systems on metallized electrospun polymeric fibers. A 3D-printed hydrophobic barrier on the chromatographic paper defines injection and testing zones. Fluid diffusion through paper and concentration gradients are considered in the design. Electrochemical characterization is performed using 40 mu L of methylene blue solution, which interacts with double-stranded nucleic acids, reducing its redox activity. This interaction mechanism within the paper substrate is confirmed by spectroscopy. The sensor achieves detection of nucleic acids in 3 min with 2 mu L of solution. Real sample analysis is performed for the quantification of PCR-amplified genes with a limit of detection of 1.38 ng mu L-1. The device serves as a promising point-of-care diagnostics tool for the direct quantification of amplified genetic material.

We investigate the energy spectrum and transport properties of a diatomic square lattice model that manifest antichiral characteristics. The emergence of antichiral edge states is primarily governed by the relative sign of the next-nearest-neighbor hopping parameters on the two sublattices. However, in finite systems, the atomic structure at the boundaries plays a crucial role in determining whether the system exhibits chiral/antichiral behavior. Using both analytical and numerical methods, we reveal the presence of antichiral edge states in ribbon geometries and emphasize the importance of atomic connectivity at the edges. Extending our analysis, we simulate various finite size geometries to identify which configuration supports antichiral behavior. The transport properties are studied in the Landauer-B & uuml;ttiker approach for a Hall device with four leads. We study the transmittance coefficients, transverse (Hall), and longitudinal resistance by comparing the antichiral versus chiral situations. In particular, the antichiral case shows a vanishing Hall effect and negative longitudinal resistance. The presence of the bulk currents is proved by calculating explicitly the currents on the plaquette and the local density of states in the system with leads. Additionally, we investigate the influence of Anderson disorder on the transmittance coefficients to highlight the reduced robustness of antichiral systems.