Tolerance, Adaptation, and Cell Response Elicited by Micromonospora sp. Facing Tellurite Toxicity: A Biological and Physical-Chemical Characterization

The intense use of tellurium (Te) in industrial applications, along with the improper disposal of Te-derivatives, is causing their accumulation in the environment, where oxyanion tellurite (TeO32−) is the most soluble, bioavailable, and toxic Te-species. On the other hand, tellurium is a rare metalloid element whose natural supply will end shortly with possible economic and technological effects. Thus, Te-containing waste represents the source from which Te should be recycled and recovered. Among the explored strategies, the microbial TeO32− biotransformation into less toxic Te-species is the most appropriate concerning the circular economy. Actinomycetes are ideal candidates in environmental biotechnology. However, their exploration in TeO32− biotransformation is scarce due to limited knowledge regarding oxyanion microbial processing. Here, this gap was filled by investigating the cell tolerance, adaptation, and response to TeO32− of a Micromonospora strain isolated from a metal(loid)-rich environment. To this aim, an integrated biological, physical-chemical, and statistical approach combining physiological and biochemical assays with confocal or scanning electron (SEM) microscopy and Fourier-transform infrared spectroscopy in attenuated total reflectance mode (ATR-FTIR) was designed. Micromonospora cells exposed to TeO32− under different physiological states revealed a series of striking cell responses, such as cell morphology changes, extracellular polymeric substance production, cell membrane damages and modifications, oxidative stress burst, protein aggregation and phosphorylation, and superoxide dismutase induction. These results highlight this Micromonospora strain as an asset for biotechnological purposes

A Biodegradable, Bio-Based Polymer for the Production of Tools for Aquaculture: Processing, Properties and Biodegradation in Sea Water

Bio-based, biodegradable polymers can dramatically reduce the carbon dioxide released into the environment by substituting fossil-derived polymers in some applications. In this work, prototypes of trays for aquaculture applications were produced via injection molding by using a biodegradable polymer, Mater-Bi®. A characterization carried out via calorimetric, rheological and mechanical tests revealed that the polymer employed shows properties suitable for the production of tools to be used in aquaculture applications. Moreover, the samples were subjected to a biodegradation test in conditions that simulate the marine environment. The as-treated samples were characterized from gravimetrical, morphological and calorimetric point of views. The obtained data showed a relatively low biodegradation rate of the thick molded samples. This behavior is of crucial importance since it implies a long life in marine water for these manufacts before their disappearing

PREPARATION AND CHARACTERIZATION OF POLYLACTIC ACID/SILICA AND POLYLACTIC ACID/CLAYS BIONANOCOMPOSITE ELECTROSPUN SYSTEMS

Introduction Electrospinning is a versatile process technology for the production of fibers ranging from nano- to micro-scale. In order to develop high performance electrospun systems, the use of nanofillers is achieving more and more interest. In this context, silica (Si) and clays (Cl) are often used as fillers due to the possibility to combine the advantages of polymeric materials, such as light weight and flexibility, and inorganic materials, such as high mechanical strength, heat stability, and chemical stability. In this work, the morphology of PLA/Si and PLA/Cl were evaluated on two different weight ratios: 99/1 and 95/5 wt/wt. Material and Methods The nanoparticles were added to a solution of TCM/Ac (2:1 volume). PLA (10 wt% with respect to the solvent phase) was then added to the mixture and completely dissolved by continuous magnetic stirring. Nanofibrous mats were produced with a filler mass ratio equal to 1% and 5%. The nanofibers were collected on a grounded rotary drum rotating at 10 rpm. The morphology of the materials was studied by using a Scanning Electron Microscope (SEM). Results SEM images revealed that PLA showed the typical morphology of an electrospun material with smooth and homogenous fibers in the nearly-nanoscale and randomly oriented. Fillers added at 1 wt% are well dispersed in the polymer matrix. Si caused a slight increase and Cl a slight reduction of the fiber diameter. PLA/Si 5 wt% fibers are characterized by a worst particles’ distribution and higher fiber diameters if compared with PLA/Cl 5 wt%. Discussion The different dispersion degree observed at high filler concentration can be likely ascribed to the different affinity of the nanoparticles with both the polymer matrix and the solvent systems. The different fiber diameter can be ascribed to the viscosity of the polymeric solution. Silica induced an increment of the viscosity and a consequent increase of the fiber diameter. The lower fiber diameter observed for PLA/Cl nanocomposites can be ascribed to the reduction of the viscosity probably due to a degradation of PLA, as already observed in other works

Multicomponent solid dispersion as a formulation strategy to improve drug permeation: A case study on the anti-colorectal cancer irinotecan

Multicomponent solid dispersions (MSD)s are frequently proposed as efficient drug delivery systems to improvedrug solubility and bioavailability. In this study, the effects of specific excipients, such as mannitol, inulin, poly(methyl methacrylate-co-methacrylic)acid (PMMA) and cellulose acetate phthalate (CAP) have been tested topotentially improve irinotecan (IRN) permeation in the intestinal tract with the intention to protect the drugfrom the gastric environment. MSDs were formulated as microparticles by Spray-Drying technique. Raw ma-terials and microparticles have been characterized by FTIR analysis to determine hydrogen bonding. SEM imageswere recorded to investigate morphology and particle size of drug-loaded microparticles, and thermal analysiswas used to confirm that drug physical morphology was maintained during formulation. Finally, in vitro dis-solution studies andex-vivoexperiments across colon sections were carried out. The drug-loaded microparticlesresulted to have an average particle size of below 6μm and increased both drug dissolution rate and permeationthrough the intestine. The use of specific excipients improved properties such as drug dissolution performancesand drug absorption through the intestinal barrier. The selected method and excipients increased IRN dissolutionrate in all the formulations prepared. Finally,ex-vivoexperiments across colon sections demonstrated an increaseof drug permeation through MSDs respect pure IRN

Composite Coatings of Chitosan and Silver Nanoparticles Obtained by Galvanic Deposition for Orthopedic Implants

In this work, composite coatings of chitosan and silver nanoparticles were presented as an antibacterial coating for orthopedic implants. Coatings were deposited on AISI 304L using the galvanic deposition method. In galvanic deposition, the difference of the electrochemical redox potential between two metals (the substrate and a sacrificial anode) has the pivotal role in the process. In the coupling of these two metals a spontaneous redox reaction occurs and thus no external power supply is necessary. Using this process, a uniform deposition on the exposed area and a good adherence of the composite coating on the metallic substrate were achieved. Physical-chemical characterizations were carried out to evaluate morphology, chemical composition, and the presence of silver nanoparticles. These characterizations have shown the deposition of coatings with homogenous and porous surface structures with silver nanoparticles incorporated and distributed into the polymeric matrix. Corrosion tests were also carried out in a simulated body fluid at 37 degrees C in order to simulate the same physiological conditions. Corrosion potential and corrosion current density were obtained from the polarization curves by Tafel extrapolation. The results show an improvement in protection against corrosion phenomena compared to bare AISI 304L. Furthermore, the ability of the coating to release the Ag+ was evaluated in the simulated body fluid at 37 degrees C and it was found that the release mechanism switches from anomalous to diffusion controlled after 3 h