María Eugenia Contreras García

A multifunctional nanostructured hybrid composed of metal–protein–ceramic was designed and then synthesized using three different methods: chemical reduction, physical adsorption, and coprecipitation. The processes yielded colloidal spherical silver nanoparticles (AgNPs) enveloped in a bovine serum albumin (BSA) corona, leading to the core–shell structure AgNPs–BSA. To enhance biocompatibility and mitigate potential toxicity associated with metallic nanoparticles, this core–shell structure was coated with a layer of calcium carbonate (CaCO₃). In order to analyze the internal structure of the resulting hybrid nanostructure (AgNPs–BSA–CaCO₃), a number of samples were produced by focused ion beam (FIB) and characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and zeta potential (ζ) measurements. The cytotoxic effect of the samples were evaluated through in vitro tests on mouse macrophage cell line RAW 264.7 ATCC TIB‐71, this was accomplished by calculating the appropriate concentrations from the dose–response curve of AgNPs. Research showed that the AgNPs–BSA–CaCO₃ mixture triggered the formation of vaterite; these findings were corroborated by FTIR and Raman techniques. The spherical nanostructures have an average diameter size of 4.3 ± 2 μm and an average roughness (R_a) of 3.11 ± 0.62 μm. Zeta potential (ζ) and isoelectric point studies reveal that this hybrid nanostructure exhibits amphoteric behavior that differs from either AgNPs or AgNPs–BSA alone. Cell viability response exceeded 75%, indicating the noncytotoxic nature of the proposed hybrid nanostructures.

The development of new devices at the nanoscale level, as therapeutic support in medical practice, has facilitated the development of drug delivery systems (DDSs) based on nanoparticles. This enables the transport of an effective dose of therapeutic agents to target cells or tissues, with no collateral damage to healthy cells. Owing to their unique properties, nanoparticles doped with rare earths have demonstrated the potential of being used as a DDS of drug molecules to target cells or tissues. In the present work, ceria-doped titania nanoparticles (CeO₂/TiO₂NPs) were used to form the DNR-CeO₂/TiO₂NPs complex as a DDS of daunorubicin (DNR), which was tested in a B-lymphocyte cell culture. The CeO₂/TiO₂NPs were synthesized via the sol–gel process in a microemulsion of reverse micelle. In general, the results indicated that the nanoparticles presented good biocompatibility and load efficiency superior to that reported in other investigations for pure titania nanoparticles, suggesting that the CeO₂/TiO₂NPs increased intracellular accumulation of the drug. These results indicate that a delivery strategy using CeO₂/TiO₂NPs is a promising approach in the medical field, particularly in anticancer therapies.

Titanium and its alloys are widely used as implant materials because of their mechanical properties and non-toxic behavior. Unfortunately, they are not bioinert, which means that they can release ions and can only fix the bone by mechanical anchorage, this can lead to the encapsulation of dense fibrous tissue in the body. The bone fixation is required in clinical conditions treated by orthopedic and dental medicine. The proposal is to coat metallic implants with bioactive materials to establish good interfacial bonds between the metal substrate and bone by increasing bioactivity. Bioactive glasses, ceramics specifically 45 S5 Bioglass, have drawn attention as a serious functional biomaterial because osseointegration capacity. The EPD method of bioglass gel precursor was proposed in the present work as a new method to obtain 45S5/Ti6A14V for dental applications. The coatings, were thermally treated at 700 and 800°C and presented the 45 S5 bioglass characteristic phases showing morphology and uniformity with no defects, quantification percentages by EDS of Si, Ca, Na, P and O elements in the coating scratched powders, showed a good proportional relationship demonstrating the obtention of the 45S5 bioglass. The corrosion tests were carried out in Hank's solution. By Tafel extrapolation, Ti6Al4V alloy showed good corrosion resistance in Hank's solution media, by the formation of a passivation layer on the metal surface, however, in the system 45S5/Ti6Al4V there was an increase in the corrosion resistance; i_con-, E_corr and corrosion rate decreased, the mass loss and the rate of release of ions, were lower in this system than in the titanium alloy without coating.

The increased use of the Ti6Al4V alloy as prosthetic material has been questioned by different authors who have confirmed its ion release when undergoing a corrosion attack by body fluids. In this work the coating of the Ti6Al4V alloy with nanostructured Zirconia is proposed through the colloidal electrophoretic deposition method (CEDP). The coatings were thermally treated at 450°C, 500°C, 600°C, 650°C and 700°C. The effect of the thermal treatment temperature on the morphology and phase content was evaluated by field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). Corrosion resistance of the Ti6Al4V alloy and the ZrO₂/Ti6Al4V system was evaluated by Tafel extrapolation, polarization resistance and electrochemical impedance spectroscopy in artificial saliva media with a pH of 7.4 at a temperature of 37°C, using an aereated electrochemical cell to simulate human buccal conditions. The Ti6Al4V alloy showed good corrosion resistance by forming a passivation TiO₂ layer on the metal surface, but there was an increase in the resistance when the Ti6Al4V alloy was coated with ZrO₂. It showed lower values in the i_corr, corrosion rate and ion release, a higher impedance modulus and a substantial polarization resistance after 24 hours.