Enhancement in the induction heating efficacy of sol-gel derived SiO2-CaO-Na2O-P2O5 bioglass-ceramics by incorporating magnetite nanoparticles.

Magnetite (Fe3O4) nanoparticle (MNP)-substituted glass-ceramic (MSGC) powders with compositions of (45 - x)SiO2-24.5CaO-24.5Na2O-6P2O5-xFe3O4 (x = 5, 8, and 10 wt%) have been prepared by a sol-gel route by introducing Fe3O4 nanoparticles during the synthesis. The X-ray diffraction patterns of the as-prepared MSGC nanopowders revealed the presence of combeite (Na2Ca2Si3O9), magnetite, and sodium nitrate (NaNO3) crystalline phases. Heat-treatment up to 700 °C for 1 h resulted in the complete dissolution of NaNO3 along with partial conversion of magnetite into hematite (α-Fe2O3). Optimal heat-treatment of the MSGC powders at 550 °C for 1 h yielded the highest relative percentage of magnetite (without hematite) with some residual NaNO3. The saturation magnetization and heat generation capacity of the MSGC fluids increased with an increase in the MNP content. The in vitro bioactivity of the MSGC pellets was evaluated by monitoring the pH and the formation of a hydroxyapatite surface layer upon immersion in modified simulated body fluid. Proliferation of MG-63 osteoblast cells indicated that all of the MSGC compositions were non-toxic and MSGC with 10 wt% MNPs exhibited extraordinarily high cell viability. The MSGC with 10 wt% MNPs demonstrated optimal characteristics in terms of cell viability, magnetic properties, and induction heating capacity, which surpass those of the commercial magnetic fluid FluidMag-CT employed in hyperthermia treatment.

Synthesized carboxymethyl-chitosan variant composites for cyclic adsorption-desorption based removal of Fe, Pb, and Cu.

The global issue of environmental contamination from industrial wastewater comprising Cu, Fe and Pb demands effective treatment strategies. In this article, a functional composite sorbent was devised to selectively remove copper, iron, and lead from a real-world mimicking wastewater system. For the purpose, high, medium, and low molecular weight chitosan with amine and hydroxyl functional groups were used as a substrate, and glutaraldehyde was used to anchor the organic compound with carboxymethyl groups. Characterization with X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray analyzer accompanied by field emission scanning electron microscope, and Brunauer-Emmett-Teller were conducted for the synthesized adsorbent. Accordingly, the properties of the adsorbent were evaluated to infer that the synthesis assured a purified and functionalized system. The surface area of the medium carboxymethyl chitosan derivative was analyzed as 31.43 m2 g-1. Various adsorption parameters were examined methodically to assess upon optimal removal requirements. The effect of adsorbent dosage, contact time and concentration on the adsorption of the studied metal ions were conducted and the optimum values were achieved at pH 3.82, 540 min contact duration and 1.2 g L-1 sorbent dose. Maximum adsorbent capacities of 344.83 mg g-1, 9.59 mg g-1, and 90.09 mg g-1 were realized for Cu, Pb, and Fe, respectively. The experimental measurements of the studied heavy metal ions inferred the best fitness of Langmuir isotherm equilibrium and pseudo second order kinetic models. Further, elution studies with easy-to-deploy low-cost acidic and basic eluents (HCl, HNO3, H2SO4, KOH, and NaOH) were conducted with cyclic adsorption-desorption strategies. These investigations confirmed the adsorbent's good reusability up to 3 cycles of adsorption and its proximity to serve as a potential material for multi-heavy metal ions elimination from complex adsorbate systems.

Assessment of sol-gel derived iron oxide substituted 45S5 bioglass-ceramics for biomedical applications.

Magnetic bioactive glass-ceramic (MGC) powders with nominal compositions of (45 - x)SiO224.5CaO24.5Na2O6P2O5xFe2O3 (x = 2, 4, 6, 8, 10, and 15 wt%) have been synthesized by a sol-gel route by systematically substituting silicon dioxide with iron oxide in Hench's 45S5 glass composition. Powder X-ray diffraction studies revealed a variation in the percentage of combeite (Ca2Na2Si3O9), magnetite (Fe3O4), and hematite (Fe2O3) nanocrystalline phases in MGC powders as a function of composition. Zeta potential measurements showed that MGC containing up to 10 wt% iron oxide formed stable suspensions. The saturation magnetization and heat generation capacity of MGC fluids increased with an increase in iron oxide content. Degradation of MGC powders was investigated in phosphate buffered saline (PBS). The in vitro bioactivity of the MGC powders taken in pellet form was confirmed by observing the pH variation as well as hydroxyapatite layer (HAp) formation upon soaking in modified simulated body fluid. These studies showed a decrement in the overall bioactivity in samples with high iron oxide content due to the proportional decrease in the silanol group. Monitoring the proliferation of MG-63 osteoblast cells in Dulbecco's Modified Eagle Medium (DMEM) revealed that MGC with up to 10 wt% iron oxide exhibited acceptable viability. The systematic study revealed that the MGC with 10 wt% iron oxide exhibited optimal cell viability, magnetic properties and induction heating capacity, which were better than those of FluidMag-CT, which is used for hyperthermia treatment.

Cyclic desorption based efficacy of polyvinyl alcohol-chitosan variant resins for multi heavy-metal removal.

The simultaneous removal of Cu, Pb and Fe from water bodies has been targeted in this work with polyvinyl alcohol (PVA) and chitosan (low, medium, and high molecular weight) derivative and with cyclic desorption efficacy target. For a varied range of adsorbent loading (0.2-2 g L-1), initial concentration (187.7-563.1 mg L-1 for Cu, 5.2-15.6 mg L-1 for Pb, and 61.85-185.55 mg L-1 for Fe), and resin contact time (5 to 720 min), batch adsorption-desorption studies were conducted. After first adsorption-desorption cycle, the optimum absorption capacity was 6.85 mg g-1 for Pb, 243.90 mg g-1 for Cu, and 87.72 mg g-1 for Fe for the high molecular weight chitosan grafted polyvinyl alcohol resin (HCSPVA). The alternate kinetic and equilibrium models were analyzed along with the interaction mechanism between metal ions and functional groups. The cyclic desorption studies were carried out with simple eluent systems such as HCl, HNO3, H2SO4, KOH, and NaOH. The experiments revealed that the HCSPVA derivative has been an impressive, reusable, and effective sorbent for the mitigation of Pb, Fe, and Cu in complex wastewater systems. This is due to its easy synthesis, excellent adsorption capacity, quick sorption rate, and remarkable regeneration capabilities.

Neuronal SNARE complex: A protein folding system with intricate protein-protein interactions, and its common neuropathological hallmark, SNAP25.

SNARE (Soluble NSF(N-ethylmaleimide-sensitive factor) Attachment Receptor) complex is a trimeric supramolecular organization of SNAP25, syntaxin, and VAMP which mediates fusion of synaptic vesicles with the presynaptic plasma membrane. The functioning of this entire protein assembly is dependent on its tetrahelical coiled coil structure alongside its interaction with a large spectrum of regulatory proteins like synaptotagmin, complexin, intersectin, etc. Defects arising in SNARE complex assembly due to mutations or faulty post-translational modifications are associated to severe synaptopathies like Schizophrenia and also proteopathies like Alzheimer's disease. The review primarily focuses on SNAP25, which is the prime contributor in the complex assembly. It is conceptualized that the network of protein interactions of this helical protein assists as a chaperoning system for attaining functional structure. Additionally, the innate disordered nature of SNAP25 and its amyloidogenic propensities have been highlighted employing computational methods. The intrinsic nature of SNAP25 is anticipated to form higher-order aggregates due to its cysteine rich domain, which is also a target for several post-translational modifications. Furthermore, the aberrations in the structure and expression profile of the protein display common patterns in the pathogenesis of a diverse synaptopathies and proteopathies. This work of SNARE literature aims to provide a new comprehensive outlook and research directions towards SNARE complex and presents SNAP25 as a common neuropathological hallmark which can be a diagnostic or therapeutic target.

The effect of the stoichiometric ratio of zinc towards the fibrillation of Bovine Serum Albumin (BSA): A mechanistic insight.

Fibrillation of proteins is a major cause of various neurodegenerative diseases and its exact mechanism of formation is yet unclear instead of extensive research. However, the role of metal ions influencing fibrillation of proteins is gaining more attention recently. Herein, we have investigated the role of various concentrations of the transition metal, Zn(II), on the fibrillation of Bovine Serum Albumin (BSA) at the physiological pH 7.4. Several biophysical and simulation techniques were employed in order to analyze the same. Thioflavin T intensity and residual protein investigations revealed that fibrillation of BSA was significantly decelerated and accelerated at 1:3 and 1:4 ratios of BSA-Zn(II), respectively; while it was found to be independent at other ratios (1:1 and 1:2). Fourier transform infrared spectroscopy analysis revealed that the transition of BSA from α-helical conformation to the ß-sheet rich structure is greatly resisted at 1:3 ratio, however, the same is promoted at 1:4 ratio. Similarly, dynamic light scattering and field emission transmission electron microscopy analyses further confirmed the above observations. Furthermore, Isothermal Titration Calorimetry revealed the interaction of Zn(II) towards four binding sites of BSA with preferential affinities. Molecular dynamics studies predicted that at 1:3 ratio, the C- and N-terminal zones of BSA were least flexible owing to more stable conformation. Moreover, the solvent accessible surface area and structural analyses showed increase in hydrophilicity and more conserved secondary structure, respectively at 1:3 ratio. We propose that BSA fibrillation is indeed dependent on particular Zn(II) concentration, the temperature of the microenvironment of BSA, the number of binding sites exposed due to unfolding and the conformation after metal binding.