Universal Nanocarrier Ink Platform for Biomaterials Additive Manufacturing

Ink engineering is a fundamental area of research within additive manufacturing (AM) that designs next‐generation biomaterials tailored for additive processes. During the design of new inks, specific requirements must be considered, such as flowability, postfabrication stability, biointegration, and controlled release of therapeutic molecules. To date, many (bio)inks have been developed; however, few are sufficiently versatile to address a broad range of applications. In this work, a universal nanocarrier ink platform is presented that provides tailored rheology for extrusion‐based AM and facilitates the formulation of biofunctional inks. The universal nanocarrier ink (UNI) leverages reversible polymer–nanoparticle interactions to form a transient physical network with shear‐thinning and self‐healing properties engineered for direct ink writing (DIW). The unique advantage of the material is that a range of functional secondary polymers can be combined with the UNI to enable stabilization of printed constructs via secondary cross‐linking as well as customized biofunctionality for tissue engineering and drug delivery applications. Specific UNI formulations are used for bioprinting of living tissue constructs and DIW of controlled release devices. The robust and versatile nature of the UNI platform enables rapid formulation of a broad range of functional inks for AM of advanced biomaterials.     

Transition metals increase hydrothermal stability of yttria-tetragonal zirconia polycrystals (3Y-TZP)

In this paper, the influence of transition metals on phase stability of zirconia in 3?mol% Y₂O₃ doped tetragonal zirconia polycrystals (3Y-TZP) in hydrothermal environments was reported. 3Y-TZP with and without stainless-steel or CoCr metal stains on the sample surface were subjected to different isothermal treatments in water vapor, and their respective monoclinic fractions were quantified by confocal Raman spectroscopy. The outputs of these spectroscopic experiments revealed transition metals conspicuously could stabilize the tetragonal zirconia polymorph in the monolithic zirconia, possibly due to the occurrence of off-stoichiometric chemistry in the presence of metal stains.     

Freeze-Dried Secretome (Lyosecretome) from Mesenchymal Stem/Stromal Cells Promotes the Osteoinductive and Osteoconductive Properties of Titanium Cages

Titanium is one of the most frequently used materials in bone regeneration due to its good biocompatibility, excellent mechanical properties, and great osteogenic performance. However, osseointegration with host tissue is often not definite, which may cause implant failure at times. The present study investigates the capacity of the mesenchymal stem cell (MSC)-secretome, formulated as a ready-to-use and freeze-dried medicinal product (the Lyosecretome), to promote the osteoinductive and osteoconductive properties of titanium cages. In vitro tests were conducted using adipose tissue-derived MSCs seeded on titanium cages with or without Lyosecretome. After 14 days, in the presence of Lyosecretome, significant cell proliferation improvement was observed. Scanning electron microscopy revealed the cytocompatibility of titanium cages: the seeded MSCs showed a spread morphology and an initial formation of filopodia. After 7 days, in the presence of Lyosecretome, more frequent and complex cellular processes forming bridges across the porous surface of the scaffold were revealed. Also, after 14 and 28 days of culturing in osteogenic medium, the amount of mineralized matrix detected by alizarin red was significantly higher when Lyosecretome was used. Finally, improved osteogenesis with Lyosecretome was confirmed by confocal analysis after 28 and 56 days of treatment, and demonstrating the production by osteoblast-differentiated MSCs of osteocalcin, a specific bone matrix protein.     

The Importance of Lipidomic Approach for Mapping and Exploring the Molecular Networks Underlying Physical Exercise: A Systematic Review

Maintaining appropriate levels of physical exercise is an optimal way for keeping a good state of health. At the same time, optimal exercise performance necessitates an integrated organ system response. In this respect, physical exercise has numerous repercussions on metabolism and function of different organs and tissues by enhancing whole-body metabolic homeostasis in response to different exercise-related adaptations. Specifically, both prolonged and intensive physical exercise produce vast changes in multiple and different lipid-related metabolites. Lipidomic technologies allow these changes and adaptations to be clarified, by using a biological system approach they provide scientific understanding of the effect of physical exercise on lipid trajectories. Therefore, this systematic review aims to indicate and clarify the identifying biology of the individual response to different exercise workloads, as well as provide direction for future studies focused on the body’s metabolome exercise-related adaptations. It was performed using five databases (Medline (PubMed), Google Scholar, Embase, Web of Science, and Cochrane Library). Two author teams reviewed 105 abstracts for inclusion and at the end of the screening process 50 full texts were analyzed. Lastly, 14 research articles specifically focusing on metabolic responses to exercise in healthy subjects were included. The Oxford quality scoring system scale was used as a quality measure of the reviews. Information was extracted using the participants, intervention, comparison, outcomes (PICOS) format. Despite that fact that it is well-known that lipids are involved in different sport-related changes, it is unclear what types of lipids are involved. Therefore, we analyzed the characteristic lipid species in blood and skeletal muscle, as well as their alterations in response to chronic and acute exercise. Lipidomics analyses of the studies examined revealed medium- and long-chain fatty acids, fatty acid oxidation products, and phospholipids qualitative changes. The main cumulative evidence indicates that both chronic and acute bouts of exercise determine significant changes in lipidomic profiles, but they manifested in very different ways depending on the type of tissue examined. Therefore, this systematic review may offer the possibility to fully understand the individual lipidomics exercise-related response and could be especially important to improve athletic performance and human health.     

Influence of nitrogen form on yield and nitrate content of subirrigated early potato

Potato is classified among the vegetables with low nitrate content but, in diet, it contributes most to the daily intake of nitrate, because of its high per capita consumption. Two trials were carried out in winter–spring and autumn–winter cycles using a trough bench subirrigation system. Potato seedlings were transplanted into pots containing peat, pumice and vermiculite in a 3:1:1 volume ratio. Both trials were carried out to compare three nutrient solutions having the same nitrogen concentration (6.4 mM ), but different ammonium:nitrate (NH₄‐N:NO₃‐N) percentage ratios (100:0, 50:50 and 0:100). In the winter–spring cycle, tubers were lower in weight and were more numerous than in the autumn–winter cycle. The tuber yield of ammonium‐fed plants was lower than with the mixed form and 100% NO₃‐N, but only in the trial carried out in the winter–spring period. Nitrate‐fed plants yielded a number of tubers almost 3‐fold higher than ammonium‐fed plants. The NO₃ content of tubers harvested in spring in the presence of 100% NH₄‐N in the nutrient solution was a 25% of that in nitrate‐fed plants (44 vs 169 mg kg^?1 of fresh mass); in tubers harvested in winter, with worse light conditions, nitrate content increased with increasing NO₃‐N in the nutrient solution (26, 109, and 225 mg kg^?1 of fresh mass with NH₄‐N:NO₃‐N 100:0, 50:50 and 0:100, respectively). The substrate electrical conductivity increased with increasing ammonium concentration in the nutrient solution, and was higher in the upper layer of the substrate. Copyright © 2004 Society of Chemical Industry     

Analysis of free glycerol in biodiesel using an electrochemical assay based on a two-enzyme platinum microelectrode system

An electroenzymatic method based on two coupled enzymatic activities (glycerokinase and glycerol-3-phosphate oxidase) was developed using a platinum microelectrode for the determination of free glycerol in biodiesel samples. The electroenzymatic method proposed showed a good linear correlation coefficient (R = 0.9894), with a linear response in the concentration range of 8.2 × 10⁻⁵ to 5.7 × 10⁻⁴% (w/w) and a limit of detection of 6.0 × 10⁻⁵% (w/w). The results obtained for the free glycerol content of select biodiesel samples were compared with their gas chromatography (GC) analyses. The relative errors for glycerol determination using this enzymatic-amperometric method were in the range of −8.0 to 3.0%. The proposed method was shown to be promising for the analysis of glycerol in biodiesel samples and a simple and inexpensive method in comparison to gas chromatography.     

Study of oxygen reduction on copper applied to the peroxidase-mediated oxidation of methylene blue

The kinetics of oxygen reduction was studied on copper in tartarate solutions using a rotating disc electrode. The effect of pH on the cathodic reduction was examined. AC impedance and cathodic polarization curves showed that the reaction is partially controlled by mass transport. At high current densities, the limiting current values showed that O₂ is reduced mainly through the four electron pathway. From measurements of density and viscosity and data taken from Levich and Tafel plots, diffusion coefficients for oxygen in tartarate medium were calculated. Peroxidase-mediated oxidation of methylene blue (MB) results using electrogenerated H₂O₂ on copper electrode showed that O₂ reduction reaction occurs in two steps producing the adsorbed intermediate species H₂O₂ by k ₂. In the absence of peroxidase, the hydrogen peroxide elimination has to be rapid with k ₃ ≫ k _M. The MB oxidation by lignin peroxidase using electrogenerated H₂O₂ was studied. After 24 h LiP is able to oxide the MB, producing different oxidized forms: azure C and thionine, with yield of 23% and 66%, respectively.