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Zinc (Zn) is essential for plant development and its deficiency can reduce agricultural productivity. Nutrient-solubilizing microorganisms offer a promising solution to enhance the zinc availability for plants. However, directly applying these microorganisms in the field presents challenges such as cell viability loss. Here, we developed a formulation using poly(vinyl alcohol) (PVA), cationic starch (CS), and zinc oxide (ZnO) for microencapsulating Bacillus megateriumvia spray drying. Our results showed that B. megateriumeffectively solubilizes zinc oxide. The PVACS-ZnO matrix provided a favorable environment for the growth and development of B. megaterium, releasing cells in quantities exceeding initial inoculation (10 log10CFU/g). Additionally, it protected the cells against adverse field conditions, maintaining bacterial viability after heat (50 °C/48 h), UV light (95% after 180 min), and fungicide/insecticide exposure (99% after 2 h), unlike free bacteria. Accelerated shelf life tests indicated prolonged stability of PVACS-ZnO microspheres, with double the estimated shelf life (14 months) compared to free bacteria (6 months). In greenhouse experiments, the formulation increased aerial and root biomass of soybean plants, and enhanced phosphorus and zinc absorption. These findings indicate that PVASC-ZnO formulations offer a promising strategy for encapsulating microorganisms and enhancing zinc availability, resulting in an effective and environmentally friendly biofertilizer product.

The synthetic polymer Polyvinyl alcohol (PVA) is known for its water solubility, non-toxicity, biodegradability, and high biocompatibility with cells. These characteristics make it a promising vehicle for beneficial microorganisms in sustainable agricultural practices. Here, we developed biodegradable films made of PVA crosslinked with citric acid (in concentrations ranging from 0 % to 30 %) to deliver Bacillus megateriumas seed coating. Physical-chemical and morphological analyses showed promising compatibility between PVA and citric acid, with the latter improving the thermal behavior of the films. The addition of 30 % citric acid significantly reduced the swelling and solubility of the films, thereby increasing their resistance to degradation, a crucial quality for seed coating. The film matrix allowed the controlled release of B. megaterium, keeping the cell viability during six months of storage and under external stresses. After exposure to heat and insecticide, the PVA film with citric acid kept cell viability in the same order as the initial concentration, which was not observed in free bacteria that decreased 2–4 orders of magnitude in cell viability. The film with encapsulated B. megateriumalso promoted soybean seed germination rates comparable to treatment with commercial polymer and superior to untreated seeds, demonstrating its viability for agricultural applications. The PVA film crosslinked with citric acid showed promising potential for encapsulating Bacillus megateriumand seed coating, benefiting microorganism protection and seed germination performance.

Although sulfur is an essential macronutrient for plants, its supply through elemental S0is not efficient, demanding its oxidation by soil microbiota before plant uptake. Thus, we demonstrate that a simple reactive mechanochemical route, using anhydrous KOH as a reactant with no need for water addition, can convert S0to bio-absorbable oxidized forms, leading to residual K+as a plant nutrient in the final composition. The powdery products obtained by 1 h (S-1 h) or 8 h (S-8 h) milling have been fully converted to HSO3–, SO32–, and SO42–, also suggesting different amounts of these sulfur oxides according to the milling. S-1 h and S-8 h were efficient for S and K fertilization, as probed by the successful growing of the forage crop Brachiaria ssp.in a greenhouse trial, with similar biomass yields observed for K2SO4(positive control) and superior to S0+ KCl (negative control). These data suggest that the mechanochemical process provides a sustainable route to increase sulfur plant bioavailability, suggesting a simple alternative that can be easily implemented in forage plant production sites such as Brachiaria ssp.

3D printing technology in tissue engineering applications provides several advantages for scaffold development, especially with natural materials, such as chitosan, which provides a biomimetic environment for cellular growth. However, chitosan hydrogel-based inks still show poor printing fidelity. In this article, we overcame this challenge by incorporating bioactive glasses (BG) nanoparticles (up to 5 wt%) into the chitosan hydrogel. The resulting inks were characterized by rheological tests, while their processability was evaluated through measurements of shape fidelity. An indirect cytotoxicity assay was also conducted to evaluate the cell viability of the printed scaffolds. The results indicated that adding BG nanoparticles to the chitosan-based ink modified its rheological properties and improved its shape-fidelity during 3D printing, which we suggest are consequences of hydrogen bonds established between the glass and the chitosan chains. Also, cytotoxicity assessment demonstrated that the resulting scaffold exhibits high cell viability. In conclusion, the proposed composite ink has optimized rheological properties for 3D printing and is promising for applications in tissue engineering.

The aim of this work was to study the influence of thermochemical treatment of ionic plasma nitriding on the resistance to micro-abrasive wear and to the corrosion process of AISI 316L and AISI 470 stainless steels. The thermochemical treatment was performed at different times and temperatures with a gas mixture of 25% H2and 75% N2. The treated materials were characterized by using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), microhardness tests, micro-abrasive wear tests (MAWTs) and corrosion tests. The results show an increase in the thickness of the layer formed by increasing treatment time and in the wear resistance of the materials studied. Temperatures exceeding 450°C favor the formation chromium nitrides, which, for being very hard broke making the formed layer brittle decreasing the wear resistance of the material. In addition, the formation of these phases substantially decrease the corrosion resistance of stainless steels.

Ag-containing bioactive glasses (Ag-BG) have been extensively studied as a bactericidal biomaterial, produced mainly by the sol-gel method over the last decades. According to the literature, sol-gel-derived Ag-BG may show metallic or ionic silver species in the glass structure. However, most of these works lack detailed information about how the addition of silver affects the glass network. In this study, we systematically produced sol-gel derived 58S glasses containing different quantities of Ag2O (1, 5, and 10 wt%), yielding glasses with different proportions of silver species (Ag0or Ag+1). Results from X-ray diffraction and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) evidenced the progressive formation of silver crystals due to the addition of silver in the glass structure. 29Si and 31P nuclear magnetic resonance and photoelectronic X-ray spectroscopies evidenced a glass depolymerization caused by Ag1+addition in the glass structure. On the other hand, the presence of silver crystals (Ag0) removes the network modifier role of silver, yielding glasses with higher network connectivity. A possible mechanism to explain the formation of silver crystals was proposed based on surface nucleation and growth. Finally, we suggest understanding Ag1+or Ag0formation as a solution to design glasses with tuned bactericidal properties.

The synthesis of silica particles at the nanoscale through the sol-gel method is of great interest due to their potential use in industrial applications. The Stöber method is the most used method for the silica nanoparticles production using ammonia as a catalyst. This work studied the sol-gel synthesis of amorphous silica nanoparticles described by Stöber, in order to evaluate the influence of the variation of the process parameters (molar ratio water/TEOS = 25 and 55, reagent feed rate = 0.6 mL/min and 18 mL/min, pH = 12 and 9 and reaction time of 0, 5, 30, 60 and 120 minutes) on the particle size distribution and structural functional groups. The particle size distribution was analyzed by dynamic light scattering (DLS) and the structural functional groups was analyzed by infrared spectroscopy through Fourier transform (FTIR). The molar ratio water/TEOS influenced the functional groups presents and the time influenced the particle diameter distribution. It was not possible to identify the influence of the feed rate and pH in the results. The particle diameters found were between 200-500nm. This result may be occurred due to mass diffusion and/or nanoparticles aggregation.

Cellulose acetate is a common industrial polymer found in several residues, with no defined recycling route. Here we propose a route for its recovery and reuse through simple mechanochemical activation in a solid basic medium to simultaneously reduce particle size and potentially hydrolyze acetate groups, followed by treatment with citric acid and H2O2. The cellulosic nanoparticles were submitted to mechanical activation in the presence of Ca(OH)2or CaCO3. The results show that the process with Ca(OH)2was enough for the hydrolysis of acetate groups, while the treatment with CaCO3reduced the particle size, keeping the acetate functional groups. In both cases, the cellulosic nanoparticles presented spherical shapes with an average diameter of 18.6 ± 3.4 nm. The nanoparticles were successfully applied in Pickering emulsions, with subtle differences in droplet sizes probably related to the differences between the functional groups of these particles.

In this work, the nucleation of bioglasses particles was approached through Dynamic Light Scattering in order to analyze how different synthesis parameters influence on the particle growth. It was evaluated the following parameters: pH between 10 and 11; surfactant concentration (PEG) between 0 to 20g/L; Three different compositions were chosen based on the 47SiO2-(38 – x)Na2O-(9 + x)CaO-6P2O5 system ( x = 0, 10 and 20). For each experimental condition, the growth kinetics (Kc.t-1) was calculated, and the obtained values were analyzed by factorial design of experiments. The results evidence that higher pH, higher surfactant concentration and lower Na/Ca ionic ratio lead to lower values growth kinetics in which, in turn, are associated with lower particle size.

In this work, the mechanical properties of magnesium doped tricalcium phosphate ceramics, considered a bioceramic for bone repair applications, were studied. Pure β-TCP and β-TCP doped with 2.25 mol% of Mg powders were synthesized through neutralization, freeze dried, uniaxially pressed and sintered at 1200°C/1h. The mechanical properties were evaluated through four points flexural and compression strength tests, fracture toughness and Young's Modulus. After the flexural strength test, the fracture's surface and their homogeneity were characterized by scanning electron microscopy. It was verified that Mg addition into β-TCP structure lead higher linear shrinkage, followed by higher residual stress, decreasing the mechanical properties compared to pure β-TCP ceramics. However, this behavior does not hinder the use of such bioceramics as bone substitutive materials, mainly in the sites that do not require high mechanical solicitations.

Among bioceramics materials, bioglasses which exhibits either a bioactive or resorbable behavior has been studied for many applications, such as bone substitutive and regeneration. When in contact with body fluid, the bioglasses can induce the formation of a hydroxyapatite surface layer. In this paper, we studied the bioactivity of a bioglass containing 48 wt %SiO2, 27 wt% Na2O, 19 wt % CaO and 6 wt %P2O5. After fusion and annealing, the samples were immersed in SBF for different periods, up to 14 days. The samples were characterized through XRD, DRIFT and SEM before and after bioactivity experiments. The overall results suggest the formation of a surface layer of consisting of hydroxyapatite, which was crystallized within seven days after in vitro experiments, leading to a suitable bioactivity. Moreover, the samples showed a glass network with high cohesion due to calcium addition, leading to materials with high corrosion resistance.

Genotype × environment interaction influences the market value of soybean [Glycine max(L.) Merr.] protein, oil, and fatty acid traits. The objectives of this research were (i) to evaluate agronomic trait performance and stability of soybean genotypes in individual environments and across environments; and (ii) to evaluate the relationship of test environments for selecting superior genotypes within the mega‐environment for soybean production in the southern region of Wisconsin. A total of 68 soybean genotypes were selected from University of Wisconsin soybean evaluation trials and grown at four locations in 2003 and 2004. Soybean genotypes, grown in trials with conventional and Roundup Ready herbicide treatments were analyzed for yield, protein, oil, and the fatty acid components palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid. Repeatability estimates among genotypes ranged from 0.27 to 0.98 with yield and the fatty acid component linolenic acid being the most sensitive to environment effects. Superior genotypes could be consistently selected for yield, protein, oil, and fatty acid components using biplot analysis and stability estimates. Among locations in the southern region in Wisconsin, Arlington provides unique information for soybean fatty acid evaluations, but similar information about soybean yield, protein, and oil with Janesville or Lancaster. So, if soybean fatty acid is not important then Arlington could be dropped as a test site.

Magnetic bioactive glass-ceramics are biomaterials applied for magnetic hyperthermia in bone cancer treatment, thereby treating the bone tumor besides regenerating the damaged bone. However, combining high bioactivity and high saturation magnetization remains a challenge since the thermal treatment step employed to grow magnetic phases is also related to loss of bioactivity. Here, we propose a new nanocomposite made of superparamagnetic iron oxide nanoparticles (SPIONs) dispersed in a sol-gel-derived bioactive glass matrix, which does not need any thermal treatment for crystallization of magnetic phases. The scanning and transmission electron microscopies, X-ray diffraction, and dynamic light scattering results confirm that the SPIONs are actually embedded in a nanosized glass matrix, thus forming a nanocomposite. Magnetic and calorimetric characterizations evidence their proper behavior for hyperthermia applications, besides evidencing inter-magnetic nanoparticle interactions within the nanocomposite. Bioactivity and in vitrocharacterizations show that such nanocomposites exhibit apatite-forming properties similar to the highly bioactive parent glass, besides being osteoinductive. This methodology is a new alternative to produce magnetic bioactive materials to which the magnetic properties only rely on the quality of the SPIONs used in the synthesis. Thereby, these nanocomposites can be recognized as a new class of bioactive materials for applications in bone cancer treatment by hyperthermia.

In this work, the nucleation of bioglasses particles was approached through Dynamic Light Scattering in order to analyze how different synthesis parameters influence on the particle growth. It was evaluated the following parameters: pH between 10 and 11; surfactant concentration (PEG) between 0 to 20g/L; Three different compositions were chosen based on the 47SiO2-(38 – x)Na2O-(9 + x)CaO-6P2O5 system ( x = 0, 10 and 20). For each experimental condition, the growth kinetics (Kc.t-1) was calculated, and the obtained values were analyzed by factorial design of experiments. The results evidence that higher pH, higher surfactant concentration and lower Na/Ca ionic ratio lead to lower values growth kinetics in which, in turn, are associated with lower particle size.