Characterisation of bare and tannase-loaded calcium alginate beads by microscopic, thermogravimetric, FTIR and XRD analyses

Incorporating enzymes into calcium alginate beads is an effective method to immobilise them and to preserve, at the same time, their catalytic activity. Sodium alginate was mixed with Aspergillus ficuum tannase in aqueous solution, and tannase-loaded calcium alginate beads were prepared using a simple droplet-based microfluidic system. Extensive experimental analysis was carried out to characterise the samples. Microscopic imaging revealed morphological differences between the surfaces of bare alginate matrix and tannase-loaded alginate beads. Thermal analysis allowed assessing the hydration contents of alginate and revealed the presence of tannase entrapped in the loaded beads, which was confirmed by vibrational spectroscopy. X-ray diffraction allowed us to conclude that alginate of tannase-loaded beads is not crystalline, which would make them suitable as carriers for possible controlled release. Moreover, they could be used in food applications to improve tea quality or clarify juices

Optimization of Optical Properties of Polycarbonate Film with Thiol Gold-Nanoparticles

A new nanostructured composite film based on thiol gold nanoparticles dispersed in polycarbonate and prepared by evaporating a solution of 1-dodecanthiol gold nanoparticles and polycarbonate was developed for applications as optical lenses. Lenses with superior mechanical properties, coloring and UV ray absorption and with the same transparency as the matrix were obtained. The supporting highly transparent polycarbonate matrix and the chloroform solution of thiol gold nanoparticles, 3 nm mean size, was mixed according to a doping protocol employing different concentrations of thiol gold nanoparticles vs. polycarbonate. The presence of nanoparticles in the polymer films was confirmed by the spectrophotometric detection of the characteristic absorbance marker peak at 540–580 nm. The nanostructured films obtained show a better coverage in the UV-vis range (250–450 nm) even at very low doping ratios, of the order of 1:1,000. These results offer a very promising approach towards the development of efficient nanostructured materials for applications to optical lenses

Atomic Force Microscopy And Anodic Porous Allumina Of Nucleic Acid Programmable Protein Arrays

The methodological aspects are here presented for the NAPPA (Nucleic Acid Programmable Protein Arrays) characterization by atomic force microscopy and anodic porous alumina. Anodic Porous Alumina represents also an advanced on chip laboratory for gene expression contained in an engineered plasmid vector. The results obtained with CdK2, CDKN1A, p53 and Jun test genes expressed on NAPPA and the future developments are discussed in terms of our pertinent and recent Patents and of their possibility to overcome some limitations of present fluorescence detection in probing protein-protein interaction in both basic sciences and clinical studies

Porous Alumina as a Promising Biomaterial for Public Health

Porous aluminum is a nanostructured material characterized by unique properties, such as chemical stability, regular uniformity, dense hexagonal porous lattice with high aspect ratio nanopores, excellent mechanical strength, and biocompatibility. This overview examines how the structure and properties of porous alumina can be exploited in the field of public health. Porous alumina can be employed for fabricating membranes and filters for bioremediation, water ultrafiltration, and microfiltration/nanofiltration, being a promising technique for having clean and fresh water, which is essential for human health. Porous alumina-based nanobiosensor coated with specific antibodies or peptides seem to be a useful tool to detect and remove pathogens both in food and in water, as well as for environmental monitoring. Further, these applications, being low-energy demanding and cost-effective, are particularly valuable in resource-limited settings and contexts, and can be employed as point of use devices in developing countries, where there is an urgent need of hygiene and safety assurance

Preparation and characterization of polycarbonate/multiwalled carbon nanotube nanocomposites

A polymer nanocomposite was produced by ultrasonic-assisted dispersion of multiwalled carbon nanotubes (MWCNTs) in a polycarbonate matrix using p-xylene and dichloromethane as the solvents. The filler loading was varied from 1 to 3 wt % in order to examine the effect of MWCNTs on the structure and properties of the composites. The nanocomposites were characterized by DSC, DTA, TGA, UV–vis, FTIR and Raman spectroscopy to evaluate the changes induced by the filler in the polymer matrix. UV–vis, FTIR and Raman spectroscopy measurements confirmed the presence of the dispersed phase in the composite films, while TGA and DSC analysis of the nanocomposites revealed enhanced thermal stability and decreased crystallinity, respectively, as compared to the neat polymer. The proposed composites can find application in a number of everyday products where polycarbonate is the base polymer

Self-Organization and/or Nanocrystallinity of Co Nanocrystals Effects on the Oxidation Process Using High-Energy Electron Beam

International audienceWe report the enhanced stability of Co nanocrystals (NCs) when they are highly ordered at both nanometer and micrometer scales. We show for the first time that both the crystalline structure of Co nanoparticles (NPs) and their 2D hexagonal organization have a significant impact on the oxidation process rate enabling to produce various types of nanostructures including core-shell NPs. The Co core can be either polycrystalline or hcp single-crystalline whereas, the oxide shell is composed either of CoO or of the spinel structrure Co3O4. The present results have been evidenced through a careful High-Resolution Transmission Electron Microscopy (HRTEM) study and are highly reproducible

Electrospinning of Transparent Polycarbonate/Cerium Oxide Nanoparticles Composite

In the current report electrospinning technique was performed, starting from a chlorinate solution of polycarbonate using different proportion to obtain transparent wire in micron scale dimension. Polycarbonate formulations were electro spun from conductive solutions with low viscosity, which offered advantages in terms of new optical transparency pathway in polycarbonate wires. The wires versatility in use was confirmed in the photonics fields1 , blended with fluorescence cyanine organic dyes2 , cotton fibres3 and to favourite remarkable mechanical properties for micro rope applications. The optical stability to the solar spectrum was also improved onto polycarbonate wires, by introduction of amorphous cerium oxide nanoparticles with average size in the range of 28 ± 2 nm. Cerium oxide is included in the lanthanide group and due its peculiar electronic configuration with its last d orbital state offer significant advantage to retard on small fibres damage effects caused by infrared radiations of solar spectrum. However, the dispersion of naked nanoparticles remains a critical problem to reduce due to well-known low range attraction force, which induce particles agglomeration behaviour as well as the fast dissolving and rapidly solvent evaporation. Another interesting aspect has been considered during formulation of wire was the amorphous polycarbonate state, which may change during the fast solvent evaporation or by induction with nanoparticles.4 It is present as an amorphous polymer with 2-3 % of crystalline domine. This last matter state condition was avoided to preserve the light transparency; for this reason a parametric approach in electrospinning which involves: voltage, concentration, electrode distance was formulated. Fibres spinning by using a tip electrode and second electrode surface were collect on glass and characterize by infrared absorption in the UV-vis spectroscopy with also AFM characterization. The stability of these micro fibres to the UV light with different polycarbonate/cerium oxide nanoparticles molar ratio were simulated by exposure to the UV lamp by an constant surface irradiation for 12, 24, 36 and 72 hours. Preliminary results acquire by using a UV lamp shown a significant increase of stability in wires polycarbonate composite with cerium oxide 5-10-15% of inclusion

Combined characterization of bovine polyhemoglobin microcapsules by UV–Vis absorption spectroscopy and cyclic voltammetry

reserved7siPolyhemoglobin produced from pure bovine hemoglobin by reaction with PEG bis(N-succynimidil succinate) as a cross-linking agent was encapsulated in gelatin and dehydrated by freeze–drying. Free carboxyhemoglobin and polyhemoglobin microcapsules were characterized by UV–Vis spectroscopy in the absorption range 450–650 nm and cyclic voltammetry in the voltage range from −0.8 to 0.6 mV to evaluate the ability to break the bond with carbon monoxide and to study the carrier’s affinity for oxygen, respectively. SEM used to observe the shape of cross-linked gelatin-polyhemoglobin microparticles showed a regular distribution of globular shapes, with mean size of ~750 nm, which was ascribed to gelatin. Atomic absorption spectroscopy was also performed to detect iron presence in microparticles. Cyclic voltammetry using an Ag–AgCl electrode highlighted characteristic peaks at around −0.6 mV that were attributed to reversible oxygen bonding with iron in oxy-polyhemoglobin structure. These results suggest this technique as a powerful, direct and alternative method to evaluate the extent of hemoglobin oxygenation.mixedKnirsch, Marcos Camargo; Dell’Anno, Filippo; Salerno, Marco; Larosa, Claudio; Polakiewicz, Bronislaw; Eggenhöffner, Roberto; Converti, AttilioKnirsch, Marcos Camargo; Dell’Anno, Filippo; Salerno, Marco; Larosa, Claudio; Polakiewicz, Bronislaw; Eggenhoffner, Roberto; Converti, Attili

Degenerative Severe Aortic Stenosis and Concomitant Coronary Artery Disease: What Is Changing in the Era of the "Transcatheter Revolution"?

Purpose of Review To summarize epidemiology, pathophysiology, prognostic relevance, and treatment options of coronary artery disease (CAD) when coupled with severe aortic stenosis (SAS). In regard to treatment options, we focused on the most recently adopted therapeutic approaches and on the future perspectives in light of the latest percutaneous and surgical technical improvements in the field of both CAD and SAS management. Recent Findings Nowadays, SAS is the most common valve disease requiring intervention, either surgical or percutaneous. On the other side, CAD is one of the leading causes of death in the developed countries. CAD and degenerative SAS share several predisposing factors and are often concurrently found in clinical practice. Despite in the last years the transcatheter aortic valve replacement (TAVR) has been deeply changing the therapeutic approach to SAS, the correct management of patients with concomitant CAD remains controversial due to limited and heterogeneous data in the literature. Coronary revascularization is often performed in patients with concomitant CAD and SAS. Complete surgical approach is still the standard of care according to international guidelines. However, in light of the recent results of TAVR trials, the therapeutic approach is expected to change. To date, percutaneous coronary intervention performed before TAVR is safe and feasible even if the optimal timing for revascularization remains debated. Due to the great complexity of the patients affected by SAS and CAD and until unquestionable truths will come from large randomized trials, the role of the Heart Team in the decision-making process is of primary importance to guarantee the best tailored therapeutic strategy for the single patient