Characterization of Crystalline Phase of TiO2 Nanocrystals, Cytotoxicity and Cell Internalization Analysis on Human Adipose Tissue-Derived Mesenchymal Stem Cells

A multi-biomarker approach to assess the sublethal effects of settleable atmospheric particulate matter from an industrial area on Nile tilapia (Oreochromis niloticus)

Iron and steel industries discharge a large amount of atmospheric particulate matter (PM) containing metals and metallic nanoparticles (NPs) that contaminate not only the air, but also settle into the aquatic environments. However, the effects of settleable atmospheric particulate matter (SePM) on aquatic fauna are still poorly understood. This study aimed to evaluate the sublethal effects of a short-term exposure to a realistic concentration of SePM on Nile tilapia (Oreochromis niloticus) using a multi-biomarker approach: relative ventricular mass (RVM) and heart function, blood oxidative stress, stress indicators, hemoglobin concentration, metallic NPs internalization, and metal bioaccumulation. Exposed fish exhibited reduced hemoglobin content and elevated plasma cortisol and glucose levels, reflecting stressed states. Furthermore, SePM caused blood oxidative stress increasing lipid and protein oxidation, decreasing glutathione levels, and inhibiting superoxide and glutathione reductase activities. SePM exposure also increased RVM and improved cardiac performance, increasing myocardial contractile force and rates of contraction and relaxation. In the heart tissue there was a significant accumulation of Fe > Zn > > Cr > Cu > Rb > Ni > V > Mn > Se > Mo > As. On the other hand, in the erythrocytes there was significant accumulation of Sn > Zn > > Cr > Ti > Mn = Ni > Nb > As > Bi. The highest bioaccumulation factors were found for Cr, Zn and Ni in both tissues. NPs (Ti, Sn, Al, Fe, Cu, Si, Zn) were also detected in ventricular myocardium of fish exposed and nanocrystallographic analysis revealed a predominance of anatase phase of TiO₂-NP, which is regarded to be more cytotoxic. The association between blood oxidative stress and energy expenditure to sustain increased cardiac pumping capacity under stress condition suggests that SePM has negative impacts on fish physiological performance, threatening their survival, growth rate and/or population establishment.

Synthesis and applications of TiO2/ZnO hybrid nanostructures by ZnO deposition on TiO2 nanotubes using electrochemical processes

In recent years, TiO2/ZnO hybrid nanostructures have been attracting the interest of the scientific community due to their excellent photoelectrochemical properties. The main advantage of TiO2/ZnO hybrid nanostructures over other photocatalysts based on semiconductor materials lies in their ability to form heterojunctions in which the valence and conduction bands of both semiconductors are intercalated. This factor produces a decrease in the band gap and the recombination rate and an increase in the light absorption range. The aim of this review is to perform a revision of the main methods to synthesise TiO2/ZnO hybrid nanostructures by ZnO deposition on TiO2 nanotubes using electrochemical processes. Electrochemical synthesis methods provide an easy, fast, and highly efficient route to carry out the synthesis of nanostructures such as nanowires, nanorods, nanotubes, etc. They allow us to control the stoichiometry, thickness and structure mainly by controlling the voltage, time, temperature, composition of the electrolyte, and concentration of monomers. In addition, a study of the most promising applications for TiO2/ZnO hybrid nanostructures has been carried out. In this review, the applications of dye-sensitised solar cell, photoelectrocatalytic degradation of organic compounds, photoelectrochemical water splitting, gas sensors, and lithium-ion batteries have been highlighted.

Sol-Gel-Derived Fibers Based on Amorphous α-Hydroxy-Carboxylate-Modified Titanium(IV) Oxide as a 3-Dimensional Scaffold

The development of novel fibrous biomaterials and further processing of medical devices is still challenging. For instance, titanium(IV) oxide is a well-established biocompatible material, and the synthesis of TiO_x particles and coatings via the sol-gel process has frequently been published. However, synthesis protocols of sol-gel-derived TiO_x fibers are hardly known. In this publication, the authors present a synthesis and fabrication of purely sol-gel-derived TiO_x fiber fleeces starting from the liquid sol-gel precursor titanium ethylate (TEOT). Here, the α-hydroxy-carboxylic acid lactic acid (LA) was used as a chelating ligand to reduce the reactivity towards hydrolysis of TEOT enabling a spinnable sol. The resulting fibers were processed into a non-woven fleece, characterized with FTIR, ¹³C-MAS-NMR, XRD, and screened with regard to their stability in physiological solution. They revealed an unexpected dependency between the LA content and the dissolution behavior. Finally, in vitro cell culture experiments proved their potential suitability as an open-mesh structured scaffold material, even for challenging applications such as therapeutic medicinal products (ATMPs).

Metallic Nanoparticles: A New Frontier in the Fight Against Leishmaniasis

Abstract:

Leishmaniasis is a cutaneous, mucocutaneous, or visceral parasitic disease caused by protozoa of the Leishmania genus. According to the World Health Organization, Leishmaniasis causes approximately 20–40 thousand deaths annually, and Brazil, India, and some countries in Africa are the most affected by this neglected disease. In addition to parasite’s ability to evade the host’s immune system, the incidence of vectors, the genetics of different hosts, and the large number of deaths are mainly due to failures in conventional treatments that have high toxicity, low effectiveness, and prolonged therapeutic regimens. Thus, the development of new alternative therapeutics with more effective and safer actions has become one of the main challenges for researchers studying leishmaniasis. Among the many research and tested options, metallic nanoparticles, such as gold, silver, zinc oxide, and titanium dioxide, have been shown to be one of the most promising therapeutic tool because they are easily prepared and chemically modified, have a broad spectrum of action, low toxicity, and can generate reactive oxygen species and other immune responses that favor their use against different species of Leishmania. This review explores the progress of the use of metallic nanoparticles as a new tool in the treatment of leishmaniasis, as well as discusses the gaps in knowledge that need to be addressed to consolidate a safe, effective, and definitive therapeutic intervention against these infections.