RESUMO
This study aimed to comprehensively assess the influence of the nanotube diameter and the presence of a silicon carbide (SiC) coating on microbial proliferation on nanostructured titanium surfaces. An experiment used 72 anodized titanium sheets with varying nanotube diameters of 50 and 100 nm. These sheets were divided into four groups: non-coated 50 nm titanium nanotubes, SiC-coated 50 nm titanium nanotubes, non-coated 100 nm titanium nanotubes, and SiC-coated 100 nm titanium nanotubes, totaling 36 samples per group. P. gingivalis and T. denticola reference strains were used to evaluate microbial proliferation. Samples were assessed over 3 and 7 days using fluorescence microscopy with a live/dead viability kit and scanning electron microscopy (SEM). At the 3-day time point, fluorescence and SEM images revealed a lower density of microorganisms in the 50 nm samples than in the 100 nm samples. However, there was a consistently low density of T. denticola across all the groups. Fluorescence images indicated that most bacteria were viable at this time. By the 7th day, there was a decrease in the microorganism density, except for T. denticola in the non-coated samples. Additionally, more dead bacteria were detected at this later time point. These findings suggest that the titanium nanotube diameter and the presence of the SiC coating influenced bacterial proliferation. The results hinted at a potential antibacterial effect on the 50 nm diameter and the coated surfaces. These insights contribute valuable knowledge to dental implantology, paving the way for developing innovative strategies to enhance the antimicrobial properties of dental implant materials and mitigate peri-implant infections.
RESUMO
All inorganic layer-by-layer (LbL) thin films composed by TiO2nanoparticles and [Al(OH)4]-anions (TiO2/AlOx) as well as Al2O3and Nb2O5nanoparticles (Al2O3/Nb2O5) have been deposited to fluorine-doped tin-oxide coated glass (FTO) surfaces and applied as blocking layers in dye-sensitized solar cells (DSCs). Structural and morphological characterization of the LbL films by different techniques reveal that inTiO2/AlOxassembly, aluminate anions undergo condensation reactions on the TiO2surface leading to the formation of highly homogeneous films with unique optical properties. After 25 depositions transmittance losses below 10% in relation to the bare FTO substrate are observed. Electrochemical impedance spectroscopy shows thatTiO2/AlOxlayers impose an effective barrier for the charge recombination at FTO/electrolyte interface with an electron exchange time constant 50-fold higher than that for bare FTO. As a result, an improvement of 85% in the overall conversion efficiency of DSCs was observed with the employment of TiO2/AlOxblocking layers.Al2O3/Nb2O5LbL films can also work as blocking layers in DSCs but not as efficient, which is associated with the poor homogeneity of the film and its capacitive behavior. The production of cost-effective blocking layers with a low light scattering in the visible region is an important feature toward the application of DSC in other Building-integrated photovoltaic applications.
RESUMO
Protein display approaches have been useful to endow the cell surface of yeasts with new catalytic activities so that they can act as enhanced whole-cell biocatalysts. Despite their biotechnological potential, protein display technologies remain poorly developed for filamentous fungi. The lignocellulolytic character of some of them coupled to the cell surface biosynthesis of valuable molecules by a single or a cascade of several displayed enzymes is an appealing prospect. Cell surface protein display consists in the co-translational fusion of a functional protein (passenger) to an anchor one, usually a cell-wall-resident protein. The abundance, spacing, and local environment of the displayed enzymes-determined by the relationship of the anchor protein with the structure and dynamics of the engineered cell wall-are factors that influence the performance of display-based biocatalysts. The development of protein display strategies in filamentous fungi could be based on the field advances in yeasts; however, the unique composition, structure, and biology of filamentous fungi cell walls require the customization of the approach to those microorganisms. In this prospective review, the cellular bases, the design principles, and the available tools to foster the development of cell surface protein display technologies in filamentous fungi are discussed.
Assuntos
Técnicas de Visualização da Superfície Celular , Proteínas Fúngicas/metabolismo , Fungos/metabolismo , Proteínas de Membrana/metabolismo , Biotecnologia , Parede Celular/química , Parede Celular/metabolismo , Proteínas Fúngicas/genética , Fungos/genética , Glicosilfosfatidilinositóis/genética , Glicosilfosfatidilinositóis/metabolismo , Proteínas de Membrana/genética , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismoRESUMO
The transducer faradaic signals of molecularly receptive interfaces associated with specific target binding can be sensitively monitored by electrochemical impedance and/or capacitance spectroscopies. A comparative evaluation of both impedimetric (associated with charge transfer resistance) and capacitive (associated with faradaic density of states) approaches was undertaken using C-reactive protein (CRP) antigen and antibody interaction as biomolecular binding model. Aiming at constructing redox free (impedimetric) and redox tethered receptive (capacitive) interfaces engineered by self-assembly monolayer, CRP sensitivity and limit of detections were comparatively assessed regarding biosensor capabilities. Binding affinity constant between CRP and anti-CRP interfacial receptor sites were additionally evaluated by the Langmuir adsorption model. Both the impedimetric and capacitive approaches reported similar values of experimental analytical parameters albeit the latter was found to have the advantage of requiring no solution redox reporter thus making it highly suitable for use in multiplexing affinity arrays.