No abstract

Three different electrodes were tested for use as nonspecific amperometric sensors for blind analysis on real matrices, namely different fruit juices from different fruits or different brands. The first two electrodes were traditional Pt and Au electrodes, while the third one was modified with poly(3,4-ethylenedioxythiophene) conducting polymer. The sensors were tested separately, tested coupled to each other, and also tested together. The responses of the electrode system(s) were first screened via PCA and then their discriminant capabilities were quantified in terms of the sensitivities and specificities of their corresponding PLS-DA multivariate classification models. Particular attention was paid to analyzing the evolution of the response over subsequent potential sweeps. The modified electrode demonstrated the most discriminating ability, and it was the only system capable of satisfactorily performing the most complex task attempted during the analysis: discriminating between juices from the same fruit but from different brands. Moreover, the electrode "cleaning" procedure required between two subsequent potential sweeps was much simpler for the modified electrode than for the others. This electrode system was therefore shown to be a good candidate for use as an informative element in an electronic tongue applied to the analysis of other food matrices.

No abstract

Hydrogels based on hyaluronic acid are used to restore volume, hydration, and skin tone, as well as to correct scars, asymmetries or defects of the soft tissue. Hyaluronic acid is often chemically crosslinked with different crosslinking agents in order to improve its mechanical and biological properties. Here we focused on defining the chemical and mechanical characterization of a new hydrogel with specific characteristics: hyaluronic acid polyethylene glycol (PEG)‐crosslinked with a high concentration of hyaluronic acid (28 mg/mL), manufactured by MatexLab Spa, via Carlo Urbani 2, ang Via Enrico Fermi, Brindisi, Italy. We made a quantitative and qualitative analysis of the content of sodium hyaluronate in the hydrogel after polymerization and sterilization processes and also evaluated histologically the bio integration of these hydrogels in the cutaneous soft tissues. The results suggest that hyaluronic acid hydrogel PEG‐crosslinked have great bio integration, great chemical and mechanical properties, compared with other products available on the market, that are cross‐linked with different cross‐linking agents. The nontoxicity and nonimmunogenicity of PEG guarantee the lack of allergic and immunological reactions. The PEG‐crosslinking technology guarantees a high duration time of the implanted hydrogel because of more resistant physiological degradation.

Recently a great interest has been expressed in electrophoretic deposition (EPD) of polymers, both as particles and as chains. It is generally accepted that also for polymer particles, the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory is valid, therefore, in principle, polymer suspensions suitable for EPD could be easily obtained by dispersing polymer particles in an aqueous or nonaqueous medium. Nevertheless, this work demonstrated that in order to obtain good quality deposits based on poly(ether ether ketone) (PEEK) and poly(tetrafluoroethylene) (PTFE), some additives have to be used. In the case of PEEK, a dispersant providing citrate anions was successfully used, whereas for PTFE a steric suspension stabilization was reached by adding polyvinylpyrrolidone (PVP). In such a way, codeposition of PEEK and PTFE was achieved. The efficiency of the EPD process was demonstrated by means of differential scanning calorimetry (DSC) measurements. A thermal program consisting of heat/cool/heat cycles at a low rate was used in order to evaluate the crystalline amount of each polymer in the deposits. In order to explain the obtained results, it needed to also consider the dimension and structural characteristic of the polymer particles.