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Protein-based materials have found applications in a wide range of biomedical fields because of their biocompatibility, biodegradability and great versatility. Materials of different physical forms including particles, hydrogels, films, fibers and microneedles have been fabricated e.g. as carriers for drug delivery, factors to promote wound healing and as structural support for the generation of new tissue. This review aims at providing an overview of the current scientific knowledge on protein-based materials, and selected preclinical and clinical studies will be reviewed in depth as examples of the latest progress within the field of protein-based materials, specifically focusing on non- and minimally invasive strategies mainly for topical application.

Protein-based materials recently emerged as good candidates for water cleaning applications, due to the large availability of the constituent material, their biocompatibility and the ease of preparation. In this work, new adsorbent biomaterials were created from Soy Protein Isolate (SPI) in aqueous solution using a simple environmentally friendly procedure. Protein microsponge-like structures were produced and characterized by means of spectroscopy and fluorescence microscopy methods. The efficiency of these structures in removing Pb2+ ions from aqueous solutions was evaluated by investigating the adsorption mechanisms. The molecular structure and, consequently, the physico-chemical properties of these aggregates can be readily tuned by selecting the pH of the solution during production. In particular, the presence of β-structures typical of amyloids as well as an environment characterized by a lower dielectric constant seem to enhance metal binding affinity revealing that hydrophobicity and water accessibility of the material are key features affecting the adsorption efficiency. Presented results provide new knowledge on how raw plant proteins can be valorised for the production of new biomaterials. This may offer extraordinary opportunities towards the design and production of new tailorable biosorbents which can also be exploited for several cycles of purification with minimal reduction in performance. Synopsis: Innovative, sustainable plant-protein biomaterials with tunable properties are presented as green solution for water purification from lead(II) and the structure-function relationship is discussed.

Nicotine replacement therapy (NRT) formulations for oromucosal administration induce a delayed rise in nicotine blood levels as opposed to the immediate nicotine increase obtained from cigarette smoking, this being a shortcoming of the therapy. Here, we demonstrate that α-lactalbumin/polyethylene oxide (ALA/PEO) electrospun nanofibers constitute an efficient oromucosal delivery system for fast-onset nicotine delivery of high relevance for acute dosing NRT applications. In vitro, nicotine-loaded nanofibers showed fast disintegration in water, with a weight loss up to 40% within minutes, and a faster nicotine release (26.1 ± 4.6% after 1 min of incubation) of the loaded nicotine compared to two relevant marketed NRT formulations with a comparable nicotine dose (i.e., 7.9 ± 5.1 and 2.2 ± 0.3% nicotine was released from a lozenge and a sublingual tablet, respectively). Model-fitting of the release data indicated that the release mechanism of nicotine from the hydrophilic nanofibers was possibly governed by more than one type of release phenomena. Remarkably, ex vivo studies using porcine buccal mucosa demonstrated a more efficient permeation of the nicotine released from the nanofibers [flux of 1.06 ± 0.22 nmol/(cm2·min)] compared to when dosing even a ten-fold concentrated nicotine solution [flux of 0.17 ± 0.14 nmol/(cm2·min)]. Moreover, matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI MS) imaging of ex vivo porcine buccal mucosa exposed to nicotine-loaded nanofibers clearly revealed higher amounts of nicotine throughout the epithelium, as well as in the lamina propria and submucosa of the tissue. Our findings suggest that nicotine-loaded ALA/PEO nanofibers have potential as a mucosal, fast-releasing, and biocompatible delivery system for nicotine, which can overcome the limitations of the currently marketed NRTs.

Electrospun nanofibers have gained great interest in many fields of research from water and air filtration or food packaging to medical use as scaffolds for tissue engineering, drug delivery systems and wound bandages. Proteins such as soy protein isolate (SPI) are biodegradable and safe polymers that can be purified from renewable and sustainable sources, and are thus interesting as building blocks for sustainable and biocompatible nanofiber-based materials. Sufficient solvent evaporation and intermolecular entanglement are required for efficient nanofiber formation. Electrospinning of proteins is therefore often achieved using organic solvents, strong bases or surfactants, which limits the safety, sustainability and usability of protein-based nanofibers. In this work, green and biocompatible electrospun nanofibers with a high content of SPI (up to 75% (w/w)) were fabricated with polyethylene oxide (PEO) as a co-spinning polymer and with water being the only solvent, thus avoiding use of any organic solvent, strong base or surfactant. A thorough biophysical assessment based on microscopy and spectroscopies, and a rheological profiling of SPI suggested that disassembly of larger structures into smaller in the SPI suspension and increase of SPI solubility improved the electrospinnability of SPI. The content of SPI in the nanofibers affected the morphology as visualized by scanning electron microscopy, brittleness assessed by dynamic mechanical analysis, and aqueous stability of the nanofibers, which are key parameters for the future use of SPI-based nanofibers. The biocompatibility of the electrospun SPI/PEO nanofibers was demonstrated by exposure of human epithelial cell monolayers (TR146) to the nanofibers without loss of cell viability. We propose that the presented strategies can serve as a universal workflow for waterborne electrospinning of other proteins or protein isolates.

Nicotine replacement therapy (NRT) formulations for oromucosal administration induce a delayed rise in nicotine blood levels as opposed to the immediate nicotine increase obtained from cigarette smoking, this being a shortcoming of the therapy. Here, we demonstrate that α-lactalbumin/polyethylene oxide (ALA/PEO) electrospun nanofibers constitute an efficient oromucosal delivery system for fast-onset nicotine delivery of high relevance for acute dosing NRT applications.

Background Cosmetic industry following the recent trends in the relative market has turned its interest in the formation of cosmeceutical products containing natural bioactive ingredients. Natural extracts may reveal undesirable sensory characteristics due to their composition. Encapsulation and nanotechnology are the most promising methods to overcome these drawbacks, opening up new perspectives for the future of cosmeceutical industry. Aims The purpose of this study was the use of nano-encapsulated plant and fruit extracts to formulate cosmeceutical facial creams with acceptable rheological characteristics. Methods Electrohydrodynamic process was used to encapsulate pomegranate and tea tree oil extracts and incorporate them in facial cosmetic creams. All the formulations including those without additives, were stored at three different temperatures. Subsequently, rheological oscillatory tests (frequency sweep tests) were performed using the dynamic mechanical analysis method in order to evaluate alterations in storage modulus (G'), loss modulus (G''), and complex viscosity (η*). Results Dynamic mechanical analysis, showed that all formulations are suitable for application in cosmetic industry, while changes due to storage period or the storage temperature were negligible. Conclusion The addition of the selected extracts' nanofibers to formulate cosmeceutical facial creams, developed products with acceptable rheological characteristics that could be decisive for the cosmetics industry.