Cytokine loaded biopolymers as a novel strategy to study stem cells during wound-healing processes

The biopolymer matrigel loaded with cytokine can be used for the recruitment in vivo of specific cell populations and as a vector for the preparation of cell cultures. Data demonstrate that the injection of the matrigel biopolymer supplemented with interleukin-8 (IL-8) in the leech Hirudo medicinalis can be used to purify cell populations showing the same morphofunctional and molecular mechanisms of specific populations of vertebrate hematopoietic precursor cells involved in tissue repair. These cells spontaneously differentiated into myofibroblasts. This approach highlights how the innovative use of a cytokine-loaded biopolymer for an in vivo cell sorting method, applied to a simple invertebrate model, can be a tool for studying myofibroblast cell biology and its regulation, step by step.     

Patterned deposition by plasma enhanced spatial atomic layer deposition

An atmospheric pressure plasma enhanced atomic layer deposition reactor has been developed, to deposit Al₂O₃ films from trimethyl aluminum and an He/O₂ plasma. This technique can be used for 2D patterned deposition in a single in‐line process by making use of switched localized plasma sources. It was observed that the sharpness of the patterns is primarily influenced by the concentration of reactive plasma species and by the dimensions of the plasma source. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Comparative analysis of commercial dermal fillers based on crosslinked hyaluronan: Physical characterization and in vitro enzymatic degradation

The cosmetic market for hyaluronic acid (HA)-based dermal fillers is in continuous and rapid growth and, simultaneously, the development of more effective and safer products is strongly intensifying. In order to highlight the differences among the currently available fillers, in terms of their physical characteristics and on the relation of such properties with product effectiveness, an in vitro evaluation of eight marketed HA-based gels was performed.Filler swelling properties, soluble HA fraction and rheological behaviour were investigated. Furthermore the relative stability to enzymatic hydrolysis was tested. The presence of soluble HA in the formulations varied from 7 ± 1(%) to 33 ± 5(%) with respect to the total HA concentration. Chromatographic analyses showed that the soluble fractions consist of low molecular weight chains (M_w: 260-480 kDa) presenting large distributions (M_w/M_n: 1.6-2.5). The investigated fillers were found to be non-equilibrium gels in their commercial formulation also showing different swelling capacities. Rheological measurements indicated a shear thinning behaviour for all the products and elastic modulus values varied over a wide range (100-1800 Pa). Fillers proved differently sensitive to enzymatic degradation. Swelling capacity and enzymatic stability were found consistently dependent on the total HA concentration, insoluble/soluble HA ratio and on the crosslinking extent.     

A new non-destructive method for chemical analysis of particulate matter filters: the case of manganese air pollution in Vallecamonica (Italy)

Total Reflection X-ray Fluorescence (TXRF) is a well-established technique for chemical analysis, but it is mainly employed for quality control in the electronics semiconductor industry. The capability to analyze liquid and uniformly thin solid samples makes this technique suitable for other applications, and especially in the very critical field of environmental analysis. Comparison with standard methods like inductively coupled plasma (ICP) and atomic absorption spectroscopy (AAS) shows that TXRF is a practical, accurate, and reliable technique in occupational settings. Due to the greater sensitivity necessary in trace heavy metal detection, TXRF is also suitable for environmental chemical analysis. In this paper we show that based on appropriate standards, TXRF can be considered for non-destructive routine quantitative analysis of environmental matrices such as air filters. This work has been developed in the frame of the EU-FP6 PHIME (Public Health Impact of long-term, low-level Mixed element Exposure in susceptible population strata) Integrated Project (www.phime.org). The aim of this work was to investigate Mn air pollution in the area of Vallecamonica (Italy).     

Factors affecting drug adsorption on beta zeolites

The adsorption behaviour of three commonly used drugs, namely ketoprofen, hydrochlorothiazide and atenolol, from diluted aqueous solutions on beta zeolites with different SiO₂/Al₂O₃ ratio (i.e. 25, 38 and 360) was investigated by changing the ionic strength and the pH, before and after thermal treatment of the adsorbents. The selective adsorption of drugs was confirmed by thermogravimetry and X‐ray diffraction. The adsorption capacity of beta zeolites was strongly dependent on both the solution pH and the alumina content of the adsorbent. Such a remarkable difference was interpreted as a function of the interactions between drug molecules and zeolite surface functional groups. Atenolol was readily adsorbed on the less hydrophobic zeolite, under pH conditions in which electrostatic interactions were predominant. On the other hand, ketoprofen adsorption was mainly driven by hydrophobic interactions. For undissociated molecules the adsorption capability increased with the increase of hydrophobicity.     

Different approaches to the study of chelating agents for iron and aluminium overload pathologies

Our objective is to illustrate the activity of the groups operating in Italy involved in identification and study of new chelating agents, mainly intended for treatment of human pathology correlated with metal overload. The objective of “chelation therapy” is removal of toxic metal ions from the human body or attenuation of their toxicity by transforming them into less toxic compounds or by dislocating them from the site at which they exert a toxic action. Because most of this research activity is related to chelating agents for iron and aluminium, diseases related to these two metal ions are briefly treated. Iron overload is the most common metal toxicity disease worldwide. The toxicity of aluminium in dialysis patients was a serious problem for haemodialysis units in the seventies and eighties of the last century. In particular, this review focuses on research performed by the group at Cagliari and Ferrara, and by that at Padova. The former is studying, above all, bisphosphonate and kojic acid derivatives, and the latter is investigating 3,4-hydroxypyridinecarboxylic acids with differently substituted pyridinic rings.

One‐Pot Semisynthesis of Exon 1 of the Huntingtin Protein: New Tools for Elucidating the Role of Posttranslational Modifications in the Pathogenesis of Huntington’s Disease

The natural enzymes involved in regulating many of the posttranslational modifications (PTMs) within the first 17 residues (Nt17) of Huntingtin exon 1 (Httex1) remain unknown. A semisynthetic strategy that allows the site‐specific introduction of PTMs within Nt17 by using expressed protein ligation (EPL) was developed. This strategy was used to produce untagged wild‐type (wt) and T3‐phosphorylated (pT3) Httex1 containing 23 glutamine residues (Httex1‐23Q). Our studies show that pT3 significantly slows the oligomerization and fibrillization of Httex1‐23Q and that Httex1 variants containing polyQ repeats below the pathogenic threshold readily aggregate and form fibrils in vitro. These findings suggest that crossing the polyQ pathogenic threshold is not essential for Httex1 aggregation. The ability to produce wt or site‐specifically modified tag‐free Httex1 should facilitate determining its structure and the role of N‐terminal PTMs in regulating the functions of Htt in health and disease.     

Monolayer control of discotic liquid crystal by electromigration of dewetted layers in thin film devices

We show that ultrathin films of a semiconductive discotic liquid crystal, viz. phthalocyanines, can be organized to form a conductive channel tens of microns long between Au electrodes with thickness control over a single monolayer. Our approach exploits the electromigration of the isotropic phase formed starting from the pretransitional region of the columnar-isotropic phase transition. Dewetted isotropic material accumulates to the negative electrode by applying a longitudinal electric field of about 1 V/microm. Dewetting and electromigration expose an ultrathin film, a few monolayers thick, exhibiting columnar liquid crystal order. The layers of this ultrathin film melt progressively above T(C) and can be individually exfoliated by electromigration, starting from the ninth down to the first monolayer. The analysis of the current flowing through the junction as a function of the temperature, together with the comparative imaging of the evolution of morphology, yields a detailed picture of the changes in the dimensionality of the conductive phthalocyanine film and allows us to extract the behavior of the order parameter. The phenomenon of electromigration opens interesting questions on the technological control of individual monolayers on device patterns.     

Study on the shear viscosity behavior of keratin/PEO blends for nanofibre electrospinning

Graessley's theory has been applied to keratin/PEO concentrated aqueous solutions giving qualitative insight to the rheology of these polymer blends in electrospinning. The shear rate dependent viscosity of different blends was compared with that of pure polymer solutions. The characteristic time τ_η was calculated by the minimum value of at the beginning of the non‐Newtonian viscosity behavior. Flow curves of PEO (at concentration from 1.0 to 7.0 wt %) reduce to a single curve by plotting η/η₀ against . Moreover, PEO solutions exhibit a linear proportionality between zero‐shear viscosity and the characteristic time η₀ ∝ τ_η. Keratin/PEO blend solutions follow the same proportionality at very high and low keratin content, whereas linearity drops when the keratin content range from 50 to 70%. The departure from the theory has been interpreted as a sign of some interaction between the macromolecules of keratin and PEO. It was supposed that keratin displaces solvent molecules and expands the PEO chain coils increasing the relaxation time of the polymer solution. This behavior was correlated with changes in the morphology of the nanofibres produced by electrospinning from these polymer blends. Finally, additive rules to zero‐shear viscosity were applied to keratin and PEO solutions, indicating that the experimental η₀ values were higher than the theoretical ones for all the proportions of the blends, especially for high keratin amount. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1193–1201, 2008