In this work is presented a new category of self-growing, fibrous, natural composite materials with controlled physical properties that can be produced in large quantities and over wide areas, based on mycelium, the main body of fungi. Mycelia from two types of edible, medicinal fungi, Ganoderma lucidum and Pleurotus ostreatus, have been carefully cultivated, being fed by two bio-substrates: cellulose and cellulose/potato-dextrose, the second being easier to digest by mycelium due to presence of simple sugars in its composition. After specific growing times the mycelia have been processed in order to cease their growth. Depending on their feeding substrate, the final fibrous structures showed different relative concentrations in polysaccharides, lipids, proteins and chitin. Such differences are reflected as alterations in morphology and mechanical properties. The materials grown on cellulose contained more chitin and showed higher Young’s modulus and lower elongation than those grown on dextrose-containing substrates, indicating that the mycelium materials get stiffer when their feeding substrate is harder to digest. All the developed fibrous materials were hydrophobic with water contact angles higher than 120°. The possibility of tailoring mycelium materials’ properties by properly choosing their nutrient substrates paves the way for their use in various scale applications.
Poly(vinylidene fluoride‐trifluoroethylene, P(VDF‐TrFE)) and P(VDF‐TrFE)/barium titanate nanoparticle (BTNP) films are prepared and tested as substrates for neuronal stimulation through direct piezoelectric effect. Films are characterized in terms of surface, mechanical, and piezoelectric features before in vitro testing on SH‐SY5Y cells. In particular, BTNPs significantly improve piezoelectric properties of the films (4.5‐fold increased d31). Both kinds of films support good SH‐SY5Y viability and differentiation. Ultrasound (US) stimulation is proven to elicit Ca2+ transients and to enhance differentiation in cells grown on the piezoelectric substrates. For the first time in the literature, this study demonstrates the suitability of polymer/ceramic composite films and US for neuronal stimulation through direct piezoelectric effect.
The valorization of vegetable waste can create opportunities to produce new valuable bioplastics. In this study, a one-step process to fully convert a variety of vegetable waste materials into bioplastic films is reported. The process is carried out in a diluted aqueous HCl solution at room temperature, it is easily scalable, and with no environmental concerns associated with the use of organic or dangerous chemicals. The generated bioplastics are completely biodegradable and environmentally friendly. Freestanding, flexible bioplastic films were obtained from vegetable waste like carrot, parsley, radicchio and cauliflower. They have similar mechanical properties with other bioplastics, like thermoplastic starch, and showed to have little migration in a food simulant. The color and the functional properties (i.e. antioxidant capability) of the starting vegetables are preserved in the bioplastics, thanks to the mild conditions of the fabrication process. The new conversion process allows the blending of the bioplastics with other natural or synthetic polymers, in order to improve their mechanical and gas barrier properties, like the oxygen permability (OP), thus expanding their field of applications. Poly vinyl alcohol (PVA)/carrot bioplastic film showed an OP of 31.2 cm3 μm m−2 day−1 kPa−1, which is lower than the OP for other synthetic films, like high density polyethylene films (HDPE), and similar to edible materials like chitosan.