Iolanda Francolini

Tissue engineering is an interdisciplinary field that develops new methods to enhance the regeneration of damaged tissues, including those of wounds. Polymer systems containing bioactive molecules can play an important role in accelerating tissue regeneration, mitigating inflammation process, and fighting bacterial infection. Chitosan (CS) has attracted much attention regarding its use in wound healing system fabrication thanks to its biocompatibility, biodegradability, and the presence of functional groups in its structure. In this work, bioactive chitosan-based membranes were obtained by both chemical and physical modifications of the polymer with glycidyl methacrylate and glycerol (GLY), respectively. The most suitable GLY concentration to obtain wound healing systems with good elongation at break, a good water vapor transmission rate (WVTR), and good wettability values was 20% (w/w). Afterwards, the membranes were crosslinked with different concentrations of ethylene glycol dimethacrylate (EGDMA). By using a concentration of 0.05 mM EGDMA, membranes with a contact angle and WVTR values suitable for the application were obtained. To make the system bioactive, 3,4-dihydrocinnamic acid (HCAF) was introduced into the membranes, either by imbibition or chemical reaction, using laccase as a catalyst. Thermal and mechanical analyses confirmed the formation of a cohesive network, which limited the plasticizing effect of GLY, particularly when HCAF was chemically bound. The HCAF-imbibed membrane showed a good antioxidant and antimicrobial activity, highlighting the potential of this system for the treatment of wound healing.

Molecular self‐assembly has significant potential in the field of sensing. Polydiacetylenes (PDAs) are conjugated polymers possessing peculiar optical properties obtained by photopolymerization of self‐assembled diacetylene monomers. Herein, the blue‐to‐red phase transition upon either thermal stimulus or interaction with cyclodextrins (CDs) of two PDAs, bearing either carboxylic (PCDA) or amino (PCDA‐NH 2 ) polar heads, is investigated to develop a colorimetric sensor for food phenolic antioxidants. The change in the PDA polar head does not affect significantly thermo‐chromatic transition. Upon thermal stimulus, in both PDAs, color transition occurs straightforward between two distinct stable states and does not involve the disordering of the PDA crystal phase, as revealed by UV–vis spectroscopy and SAXS analysis. Contrarily, PDA/ α ‐CD interaction is influenced by intermolecular forces among PDA polar heads and is more efficient for PCDA. α ‐CDs presumably cause changes in both PDA backbone conformation and local environment surrounding the individual PDA chains. The PCDA/ α ‐CD assemblies are investigated as colorimetric sensors for the detection of Tyrosol (Ty) and caffeic acid (CAF), by using the principle of competitive inclusion complex formation. The system results to be more sensitive to CAF than Ty and may permit the determination of CAF in concentration ranges suitable for different food products.