Cyanobacterial extracellular polymeric substances are polymeric materials that own characteristics suitable for industrial and biotechnological applications. The thermophilic cyanobacteria Gloeocapsa gelatinosa was cultivated in a cylindrical reactor and the production of biomass and EPSs were investigated during a 15 days period. The results revealed that this strain is amongst the most efficient EPSs producer (0.8 g L-1 in 12 days). EPSs produced were sulphated heteropolysaccharides composed by nine different monosaccharides and two uronic acids. Thermogravimetric analysis showed that EPSs were extremely thermostable and the atomic force microscopy analysis showed that they are formed by pointed structural. Beyond that, EPSs presented high levels for water holding capacity and water holding index. The EPSs display an effective antioxidant activity via directly scavenging free radicals, particularly DDPH when compared to L-ascorbic acid (IC50 of 0.2 and 0.6 g L-1, respectively) and as a metal chelating agent when compared to EDTA (0.6 and 0.8 g L-1, respectively). The results obtained stimulate the industrial exploitation of this thermophilic Gloeocapsa gelatinosa for the production of EPSs with several biotechnological applications in the food, medicine, pharmaceutical and related fields.

Polyhydroxyalkanoates (PHAs) or bacterial polyesters, as they are commonly known, is a category of novel polymers because due to their biodegradability. Poly-4-hydroxybutyrate (P4HB) is one of the most developed polyhydroxyalkanoate that has several promising absorbable biomaterial applications such as implants, sutures, stents and tissue engineering scaffolds. They also have potential for controlled release drug delivery applications using various therapeutic chemicals and drugs, most of which are thermally sensitive. P4HB is typically melt spun and drawn into fibers at temperatures between 180 – 210 °C, although higher molecular weight P4HB (>800 K) need even higher temperatures for processing because of the high melt viscosity. Such high temperatures of P4HB melt processing prevents the incorporation of drugs in the polymer structure during the spinning stage, as most drugs are susceptible to high temperatures and can breakdown during the process. Hence a post spinning drug incorporation process such as coating or surface absorption is required. The secondary steps have major disadvantages, such as non-uniform absorption, and uneven and unpredictable release profile. This raises the need for a low temperature process for producing P4HB fibers that can address the drawbacks associated with incorporating drugs in a post melt spinning process. Presently, there is no defined procedure to produce P4HB fibers through a solution or wet spinning process. Hence, this work focuses on identifying suitable wet spinning process conditions for poly (4- hydroxybutyrate) (P4HB) and developing a scalable method for the continuous extrusion of P4HB fibers. Based on the results of this project, a suitable combination of these parameters will be used to further produce drug loaded P4HB monofilaments and study their fiber properties as well as their drug release profiles.

Nowadays, the development of materials from natural resources is a key issue for sustainability. Moreover, making use of natural polymers in industrial processes may contribute to lower cost and environmentally friendlier added-value products. Among bio-renewable polymers, cellulose is the most abundant and has drawn huge attention due to its biodegradability, nontoxicity, biocompatibility, availability and functionality. Weaknesses of cellulose stem partly from its high polarity and hydrophilic nature. Therefore, in order to fully exploit its potential, chemical modifications are often introduced, mostly by grafting. Indeed, the creation of synthetic polymer branches imparting specific features to cellulose (e.g. external stimulation by pH/temperature/ionic strength, amphiphilic features, etc), without destroying its aforementioned useful intrinsic properties, is often considered. The grafting of many synthetic polymers into cellulose has been achieved through different approaches, including diverse radical polymerization techniques. In the present research, we explore “controlled radical polymerization” (CRP) to create sustainable materials with tailored structure, incorporating natural cellulose, to purify/concentrate phenolic compounds present in plant residues (e.g. olive tree and olive oil production residues). Indeed, phenolic compounds are natural molecules that confer a multitude of health benefits, thus attracting the interest of the pharmaceutical and food industries for their commercial use. However, their weight content in raw materials is rather small and they are mixed with unwanted species. Thus, efficient enrichment and purification methods must be used to conceive feasible industrial processes.

This study presents antibiofilm coating formulations based on Pickering emulsion templating. The coating contains no bioactive material because its antibiofilm properties stem from passive mechanisms that derive solely from the super hydrophobic nature of the coating. Moreover, unlike most of the super hydrophobic formulations, our system is fluorine-free, thus making the method eminently suitable for food and medical applications. The coating formulation is based on water in toluene or xylene emulsions that are stabilized using commercial hydrophobic silica, with polydimethylsiloxane (PDMS) dissolved in toluene or xylene. The structure of the emulsions and their stability was characterized by confocal microscopy and cryogenic-scanning electron microscopy (cryo-SEM). The most stable emulsions are applied on polypropylene (PP) surfaces and dried in an oven to form PDMS/silica coatings in a process called emulsion templating. The structure of the resulting coatings was investigated by atomic force microscopy (AFM) and SEM. The surface of the coatings shows a honeycomb-like structure that exhibits a combination of micron-scale and nanoscale roughness, which endows it with its super hydrophobic properties. After tuning, the super hydrophobic properties of the coatings demonstrated highly efficient passive antibiofilm activity. In vitro antibiofilm trials with E. coli indicate that the coatings reduced the biofilm accumulation by 83% in the xylene−water-based surfaces and by 59% in the case of toluene−water-based surfaces.

The exponential increasing need of materials with good dielectric performance, the growth of biopolymer based composites and the limitation of fossil resources creates the basis for developing new biobased and or biodegradable structures adapted for a large panel of dielectric application. Although work has already been carried out in this field of materials science, many limitations of the polymer matrix still exist to fully benefit from the dielectric performance of these promising new materials. To study more closely the dielectric performance of bio-nanocomposites materials, many researchers focus on developing this kind of materials and work intensively to. In this context, our research project aims to • evaluate the dielectric potential of bio-sourced and/or biodegradable polymers for the preparation of bionanocomposite polymer-particle blends, • Study and improve the multiphysical (mechanical, microstructural) and dielectric properties of biodegradable polymer blends by incorporating different particle rates. Different polymers blends (PLA-PHBV, PLA-Cellulose Acetate, and PHBV- Cellulose Acetate) were prepared by different technology (extrusion and 3d printing) and their physical, rheological and dielectric behavior were studied. The presentation will focus on methods for optimizing the matrix, biobased fillers and nanocomposites to facilitate the integration of these new materials into electronic applications.

The use of drugs per si may lead to fluctuations where whose drugs in the organism may reach levels lower than the minimum effective concentration or exceed the maximum toxic concentration, resulting in undesirable side effects, or the lack of therapeutic benefits intended for the patient. The specific structure of clay has the ability to interact with drugs and release then, which can provide an efficient drug delivery system. The clay incorporation in the bio polymeric matrixes, like bacterial cellulose offer several advantages for the use in the design of new and efficient pharmacological systems. In these systems, the drug is typically entrapped in the clay and protected by the biopolymer matrix, and both components contribute to a gradual release of the drug. This new family of composite materials frequently exhibits remarkable improvements on the material properties when compared with the matrix polymers alone or conventional micro- and macrocomposites, namely the biocompatibility and biodegradability, which makes them suitable for healthcare applications. These biohybrids nanocomposites have attracted great attention worldwide from both academic and industrial points of view. The goal of this study was the development of a biohybrid nanocomposite made with regenerated bacterial cellulose and clay for the incorporation and delivery of drugs. The clay used was the biogenic clays from Porto Santo Island, Madeira archipelago, known by the medicinal proprieties and are used in dermopharmacy and dermocosmetics. A novel nanocomposite was successfully synthesized, verifying that 40% is the optimum clay concentration to be incorporated in the nanocellulosic matrix. The incorporation of a drug model (sodium sulfacetamide) at different concentrations, show that the optimum drug concentration is 1%. The temporal release of the drug was tested and was verified that the total drug release occurs in the first 10 minutes. The obtained results expand the possible applications of the regenerated bacterial cellulose and the Porto Santo clay to the pharmacologic field.