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Hydrotalcites (HTlcs) are a class of nanostructured layered materials that may be employed in a variety of applications, from green to bio technologies. In this paper, we report an investigation on HTlcs made of Mg and Fe, recently employed to improve the growth in vitro of osteoblasts within a keratin sponge. We carried out an analysis of powder materials and of HTlcs dispersed in keratin and spin-coated on a Si/SiO2 substrate at different temperatures. A magnetic study of the powders was carried out with a Quantum Design Physical Property Measurement System equipped with a Vibrating Sample Magnetometer. The data gathered prove that these HTlcs are fully paramagnetic, and keratin showed a very small magnetic response. Optical and Atomic Force Microscopy analyses of the thin films provide a detailed picture of clusters randomly dispersed in the films with various dimensions. The magnetic properties of these films were characterized using the Nano Magneto Optical Kerr Effect (NanoMOKE) down to 7.5 K. The data collected show that the local magnetic properties can be mapped with a micrometric resolution distinguishing HTlc regions from keratin ones. This approach opens new perspectives in the characterization of these composite materials.

Recent studies have proposed that the bioelectrical response of glial cells, called astrocytes, currently represents a key target for neuroregenerative purposes. Here, we propose the fabrication of electrospun nanofibres containing gelatin and polyaniline (PANi) synthesized in the form of nano-needles (PnNs) as electrically conductive scaffolds to support the growth and functionalities of primary astrocytes. We report a fine control of the morphological features in terms of fibre size and spatial distribution and fibre patterning, i.e. random or aligned fibre organization, as revealed by SEM- and TEM-supported image analysis. We demonstrate that the peculiar morphological properties of fibres - i.e., the fibre size scale and alignment - drive the adhesion, proliferation, and functional properties of primary cortical astrocytes. In addition, the gradual transmission of biochemical and biophysical signals due to the presence of PnNs combined with the presence of gelatin results in a permissive and guiding environment for astrocytes. Accordingly, the functional properties of astrocytes measured via cell patch-clamp experiments reveal that PnNs do not alter the bioelectrical properties of resting astrocytes, thus setting the scene for the use of PnN-loaded nanofibres as bioconductive platforms for interfacing astrocytes and controlling their bioelectrical properties.

Astrocytes are non-neuronal cells that govern the homeostatic regulation of the brain through ions and water transport, and Ca2+ -mediated signaling. As they are tightly integrated into neural networks, label-free tools that can modulate cell function are needed to evaluate the role of astrocytes in brain physiology and dysfunction. Using live-cell fluorescence imaging, pharmacology, electrophysiology, and genetic manipulation, we show that pulsed infrared light can modulate astrocyte function through changes in intracellular Ca2+ and water dynamics, providing unique mechanistic insight into the effect of pulsed infrared laser light on astroglial cells. Water transport is activated and, IP3 R, TRPA1, TRPV4, and Aquaporin-4 are all involved in shaping the dynamics of infrared pulse-evoked intracellular calcium signal. These results demonstrate that astrocyte function can be modulated with infrared light. We expect that targeted control over calcium dynamics and water transport will help to study the crucial role of astrocytes in edema, ischemia, glioma progression, stroke, and epilepsy.

Astrocytes are key regulators of brain homeostasis, an important physiological process that includes but is not limited to buffering of extracellular K+, equilibrating osmotic gradients, regulating pH, uptake of neurotransmitters, and releasing growth factors – all of which are essential for proper cognitive function. While previous studies have revealed how specific molecular components of the astrocytic cytoskeleton affect the efficacy of these homeostatic processes, none have studied how homeostasis is linked to the excitable systems character of the cytoskeleton. As recently discovered, excitability of the actin cytoskeleton manifests in second-scale dynamic fluctuations and acts as a sensor of chemo-physical environmental cues. Here we find that homeostatic regulation may be more active than previously thought, involving the excitable dynamics of actin in certain subcellular regions, especially near the cell boundary. Our results further indicate that actin dynamics concentrates into “hotspot” regions that selectively respond to certain chemo-physical stimuli, specifically the homeostatic challenges of ion or water concentration increases. Substrate topography makes the actin dynamics of astrocytes weaker. Superresolution images demonstrate that surface topography is also associated with predominant perpendicular alignment of actin filaments near the cell boundary whereas flat substrates result in an actin cortex mainly parallel to the cell boundary. Additionally, co-culture with neurons increases both the probability of actin dynamics and the strength of hotspots. The excitable systems character of actin thus makes astrocytes direct participants in neural cell network dynamics.

In this study, a bio-based polymeric system loaded with fruit by-products was developed. It was based on silk fibroin produced by the silkworm Bombyx mori and pomegranate peel powder, selected as active agent. The weight ratio between fibroin and pomegranate powder was 30:70. Pads also contained 20% w/w of glycerol vs. fibroin to induce water insolubility. Control systems, consisting of only fibroin and glycerol, were produced as reference. Both control and active systems were characterized for structural and morphological characterization (Fourier-transform infrared spectroscopy and optical microscope), antioxidant properties and antimicrobial activity against two foodborne spoilage microorganisms. Results demonstrate that under investigated conditions, an active system was obtained. The pad showed a good water stability, with weight loss of about 28% due to the release of the active agent and not to the fibroin loss. In addition, this edible system has interesting antioxidant and antimicrobial properties. In particular, the pad based on fibroin with pomegranate peel recorded an antioxidant activity of the same order of magnitude of that of vitamin C, which is one of the most well-known antioxidant compounds. As regards the antimicrobial properties, results underlined that pomegranate peel in the pad allowed maintaining microbial concentration around the same initial level (104 CFU/mL) for more than 70 h of monitoring, compared to the control system where viable cell concentration increased very rapidly up to 108 CFU/mL.

Recent studies have proposed that the bioelectrical response of glial cells, called astrocytes, currently represents a key target for neuroregenerative purposes. Here, we propose the fabrication of electrospun nanofibres containing gelatin and polyaniline (PANi) synthesized in the form of nano-needles (PnNs) as electrically conductive scaffolds to support the growth and functionalities of primary astrocytes. We report a fine control of the morphological features in terms of fibre size and spatial distribution and fibre patterning, i.e. random or aligned fibre organization, as revealed by SEM- and TEM-supported image analysis. We demonstrate that the peculiar morphological properties of fibres – i.e., the fibre size scale and alignment – drive the adhesion, proliferation, and functional properties of primary cortical astrocytes. In addition, the gradual transmission of biochemical and biophysical signals due to the presence of PnNs combined with the presence of gelatin results in a permissive and guiding environment for astrocytes. Accordingly, the functional properties of astrocytes measured via cell patch-clamp experiments reveal that PnNs do not alter the bioelectrical properties of resting astrocytes, thus setting the scene for the use of PnN-loaded nanofibres as bioconductive platforms for interfacing astrocytes and controlling their bioelectrical properties.

Water purification technologies possibly based on eco-sustainable, low cost, and multifunctional materials are being intensively pursued to resolve the current water scarcity and pollution. In this scenario, polysulfone hollow porous granules (PS-HPGs) prepared from scraps of the industrial production of polysulfone hollow fiber membranes were recently introduced as adsorbents and filtration materials for water and air treatment. Here, we report the functionalization of PS-HPGs with polydopamine (PD) nanoparticles for the preparation of a new versatile and efficient adsorbent material, namely, PSPD-HPGs. The in situ growth of PD under mild alkaline oxidative polymerization allowed us to stably graft PD on polysulfone granules. Enhanced removal efficiency of ofloxacin, an antibiotic drug, with an improvement up to 70% with respect to the pristine PS-HPGs, and removal of Zn(II) and Ni(II) were also observed after PD modification. Remarkably, removal of Cu(II) ions with an efficiency up to 80% was observed for PSPD-HPGs, whereas no adsorption was found for the PD-free precursor. Collectively, these data show that modification with a biocompatible polymer such as PD provides a simple and valuable tool to enlarge the field of application of polysulfone hollow granules for water remediation from both organic and metal cation contaminants.

In this work keratin/poly(lactic acid) (PLA) 50/50 wt blend nanofibers with different loadings of graphene-oxide (GO) were prepared by electrospinning and tested as delivery systems of Rhodamine Blue (RhB), selected as a model of a drug. The effect of GO on the electrospinnability and drug release mechanism and kinetics was investigated. Rheological measurements carried out on the blend solutions revealed unsatisfactory compatibility between keratin and PLA under quiet condition. Accordingly, poor interfacial adhesion between the two phases was observed by SEM analysis of a film prepared by solution casting. On the contrary, keratin chains seem to rearrange under the flux conditions of the electrospinning process thus promoting better interfacial interactions between the two polymers, thereby enhancing their miscibility, which resulted in homogeneous and defect-free nanofibers. The loading of GO into the keratin/PLA solution contributes to increase its viscosity, its shear thinning behavior, and its conductivity. Accordingly, thinner and more homogeneous nanofibers resulted from solutions with a relatively high conductivity coupled with a pronounced shear thinning behavior. FTIR and DSC analyses have underlined, that while the PLA/GO interfacial interactions significantly compete with the PLA/keratin ones, there are no significant effects of GO on the structural organization of keratin in blend with the PLA. However, GO offers several advantages from the application point of view by slightly improving the mechanical properties of the electrospun mats and by slowing down the release of the model drug through the reduction of the matrix swelling.

Graphene nanosheets are mechanically strong but flexible, electrically conductive and bio-compatible. Thus, due to these unique properties, they are being intensively studied as materials for the next generation of neural interfaces. Most of the literature focused on optimizing the interface between these materials and neurons. However, one of the most common causes of implant failure is the adverse inflammatory reaction of glial cells. These cells are not, as previously considered, just passive and supportive cells, but play a crucial role in the physiology and pathology of the nervous system, and in the interaction with implanted electrodes. Besides providing structural support to neurons, glia are responsible for the modulation of synaptic transmission and control of central and peripheral homeostasis. Accordingly, knowledge on the interaction between glia and biomaterials is essential to develop new implant-based therapies for the treatment of neurological disorders, such as epilepsy, brain tumours, and Alzheimer's and Parkinson's disease. This work provides an overview of the emerging literature on the interaction of graphene-based materials with glial cells, together with a complete description of the different types of glial cells and problems associated with them. We believe that this description will be important for researchers working in materials science and nanotechnology to develop new active materials to interface, measure and stimulate these cells.

Recent studies have proposed that the bioelectrical response of glial cells, called astrocytes, currently represents a key target for neuroregenerative purposes. Here, we propose the fabrication of electrospun nanofibres containing gelatin and polyaniline (PANi) synthesized in the form of nano-needles (PnNs) as electrically conductive scaffolds to support the growth and functionalities of primary astrocytes. We report a fine control of the morphological features in terms of fibre size and spatial distribution and fibre patterning

In this work, nano-hybrid electrospun non-woven mats made of wool keratin combined with diclofenac loaded hydrotalcites (HTD) were prepared and characterized as potential drug delivery systems and scaffolds for fibroblast cell growth. Nano-hybrid electrospun non-woven mats showed a good adaptability to wet skin, effortlessly conforming to the three-dimensional topography of the tissue. Nanosized HTD exercised an overall reinforcing action on the electrospun non-woven mats since the nanohybrid samples displayed a reduced swelling ratio and a slower degradation profile compared to keratin-based nanofiber non-woven mats containing free diclofenac, without negative effects on drug release. The cell viability test indicated a decreased toxicity of the drug when loaded into nanofibers and confirmed the biocompatibility of keratin/HTD electrospun non-woven mats; moreover, a controlled diclofenac release within the first 24 hours does not compromise the fibroblast cell growth in a significant manner.

Research over the past four decades has highlighted the importance of certain brain cells, called glial cells, and has moved the neurocentric vision of structure, function, and pathology of the nervous system toward a more holistic perspective. In this view, the demand for technologies that are able to target and both selectively monitor and control glial cells is emerging as a challenge across neuroscience, engineering, chemistry, and material science. Frequently neglected or marginally considered as a barrier to be overcome between neural implants and neuronal targets, glial cells, and in particular astrocytes, are increasingly considered as active players in determining the outcomes of device implantation. This review provides a concise overview not only of the previously established but also of the emerging physiological and pathological roles of astrocytes. It also critically discusses the most recent advances in biomaterial interfaces and devices that interact with glial cells and thus have enabled scientists to reach unprecedented insights into the role of astroglial cells in brain function and dysfunction. This work proposes glial interfaces and glial engineering as multidisciplinary fields that have the potential to enable significant advancement of knowledge surrounding cognitive function and acute and chronic neuropathologies.

In this work we report the preparation and characterization of free-standing keratin-based films containing Au/Ag nanorods. The effect of nanorods surface chemistry on the optical and mechanical properties of keratin composite films is fully investigated. Colloid nanorods confer to the keratin films interesting color effects due to plasmonic absorptions of the metal nanostructures. The presence of metal NRs induces also substantial change in the protein fluorescence emission. In particular, the relative contribution of the ordered-protein aggregates emission is enhanced by the presence of cysteine and thus strictly related to the surface chemistry of nanorods. The presence of more packed supramolecular structures in the films containing metal nanorods (in particular cysteine modified ones) is confirmed by ATR measurements. In addition, the films containing nanorods show a higher Young's modulus compared to keratin alone and again the effect is more pronounced for cysteine modified nanorods. Collectively, the reported results indicate the optical and mechanical properties of keratin composites films are related to a common property and can be tuned simultaneously, paving the way to the optimization and improvement of their performances and enhancing the exploitation of keratin composites in highly technological optoelectronic applications.

In this work, keratin sponges were prepared by freeze-drying method and tested for adsorption of Azure A and Methyl Orange dyes. The obtained materials showed a porosity of 99,92% and a mean pore size dimension of about 91μm. The use of oxidized sucrose with a heating treatment at 150°C was demonstrated to be a useful crosslinking procedure alternative to the conventional glutaraldehyde. Keratin sponges showed a maximum adsorption capacity of 0.063 mmol/g and of 0.037 mmol/g for Azure A and Methyl Orange, respectively. The absorption of the cationic dye AzureA onto keratin sponges was better described by Freundlich model while the isotherm adsorption of the anionic Methyl Orange was found to correlate with both Langmuir and Freundlich models. The mean free energies evaluated by using the D-R model indicated a physisorption of Methyl Orange and a chemisorptions of Azure A onto keratin sponges. Finally, the functionalization of keratin sponges with Zn Al hydrotalcites nanoparticles did not affect the adsorption performances of the adsorbent towards the cationic dye Azure A, while it improved those towards the anionic Methyl Orange, increasing the related removal efficiencies from 43% to 96%. Collectively, the reported data indicates that the combination of keratin with hydrotalcites nanoparticles is a good strategy to obtain more functional adsorbent materials of potential interest for water treatment and purification.

The correct human brain function is dependent on the activity of non-neuronal cells called astrocytes. The bioelectrical properties of astrocytes in vitro do not closely resemble those displayed in vivo and the former are incapable of generating action potential; thus, reliable approaches in vitro for noninvasive electrophysiological recording of astrocytes remain challenging for biomedical engineering. Here it is found that primary astrocytes grown on a device formed by a forest of randomly oriented gold coated-silicon nanowires, resembling the complex structural and functional phenotype expressed by astrocytes in vivo. The device enables noninvasive extracellular recording of the slow-frequency oscillations generated by differentiated astrocytes, while flat electrodes failed on recording signals from undifferentiated cells. Pathophysiological concentrations of extracellular potassium, occurring during epilepsy and spreading depression, modulate the power of slow oscillations generated by astrocytes. A reliable approach to study the role of astrocytes function in brain physiology and pathologies is presented.

In recent years there has been a growing interest in the use of proteins as biocompatible and environmentally friendly biomolecules for the design of wound healing and drug delivery systems. Keratin is a fascinating protein, obtainable from several keratinous biomasses such as wool, hair or nails, with intrinsic bioactive properties including stimulatory effects on wound repair and excellent carrier capability. In this work keratin/poly(butylene succinate) blend solutions with functional properties tunable by manipulating the polymer blending ratios were prepared by using 1,1,1,3,3,3-hexafluoroisopropanol as common solvent. Afterwards, these solutions doped with rhodamine B (RhB), were electrospun into blend mats and the drug release mechanism and kinetics as a function of blend composition was studied, in order to understand the potential of such membranes as drug delivery systems. The electrophoresis analysis carried out on keratin revealed that the solvent used does not degrade the protein. Moreover, all the blend solutions showed a non-Newtonian behavior, among which the Keratin/PBS 70/30 and 30/70 ones showed an amplified orientation ability of the polymer chains when subjected to a shear stress. Therefore, the resulting nanofibers showed thinner mean diameters and narrower diameter distributions compared to the Keratin/PBS 50/50 blend solution. The thermal stability and the mechanical properties of the blend electrospun mats improved by increasing the PBS content. Finally, the RhB release rate increased by increasing the keratin content of the mats and the drug diffused as drug-protein complex.

In this work, keratin sponges (Ks) containing magnetic MgFe hydrotalcites (HTlc) nanoparticles were prepared by freeze-drying and tested as 3D scaffolds for tissue regeneration. HTlc nanoparticles were well dispersed in the protein matrix and preserved their lamellar structure. The obtained hybrid materials showed a mean pore diameter of about 48 μm and a swelling ratio of about 6, higher than that of pure Ks (~ 4). Magnetic measurements indicated that the Ks-HTlc samples were magnetized more easily that the pure HTlc ones. Finally, the cell viability test, performed on osteoblasts under the effect of an applied static magnetic field, showed a substantial increase in cellular activity in the hybrid Ks-HTlc sponges compared to the nonmagnetic Ks sponges. Taken together, the reported results indicate that combining keratin with magnetic HTlc nanoparticles is a good strategy to obtain innovative 3D scaffold of potential interest in tissue regeneration, especially bone.

The spatial confinement of water in graphene-oxide membranes has been studied at room temperature using deep inelastic neutron scattering. This technique enabled the non-invasive measurement of water levels in hydrated and dried specimens, as well as of proton mean kinetic energies. For the first time, the latter observables are provided for the special case of graphene-oxide membranes. Absolute values of the mean kinetic energy provide direct insight into the local chemical environment of the proton under spatial confinement. In conjunction with parallel X-ray diffraction, atomic force microscopy, and thermal-gravimetric analysis measurements, our experimental results show that the characteristic, quasi-twodimensional confinement of water between graphene-oxide sheets results in a binding environment remarkably similar to that in the bulk. We surmise that this behaviour arises from a small fraction of hydroxyl groups relative to water molecules in graphene-oxide membranes, as well as the predominance of non-specific and weak interactions between water and the underlying nanostructured substrate.

This work investigates the preparation of wool keratin sponges by freeze-drying procedure starting form keratin aqueous solutions. The study highlights the correlations between process parameters (protein concentration and freezing rate) and the chemical-physical properties of the final sponges.In particular, as the keratin concentration increases from 1 to 20% wt, the mean pore size and the porosity decrease from 62 to 37 μm and from 94 to 50% respectively, while the chemical stability in physiological conditions increases, as well as the thermal stability and the elastic modulus. On the other hand, the increase of the freezing rate affects the design of sponges that appear as stacked leaflets structures with oriented pores.Moreover, in order to confer to keratin sponges antioxidant properties, polydopamine (PDA) nanoparticles were used as fillers. To this end, PDA nanoparticles of about 130 nm were successfully dispersed in the sponges, bestowing time-dependent anti-oxidant properties on the scaffolds, with no significant modification of sponges morphological structure as well as reduction of the thermal stability and mechanical behaviour. Keywords: Keratin, Polydopamine, Scavenging activity, Pore structure, Tissue engineering

The technological quest for flexible devices to be interfaced with the biological world has driven the recent reinvention of bioderived polymers as multifunctional active and passive constituent elements for electronic and photonic devices to use in the biomedical field. Keratin is one of the most important structural proteins in nature to be used as biomaterial platform in view of the recently reported advances in the extraction and processing from hair and wool fibers. In this article we report for the first time the simultaneous use of naturally extracted keratin as both active ionic electrolyte for water ions sensing and as bendable and insoluble substrate into the same multielectrode array-based device. We implemented the multifunctional system exclusively made by keratin as a bendable sensor for monitoring the humidity flow. The enhancement of the functional and structural properties of keratin such as bendability and insolubility were obtained by unprecedented selective chemical doping. The mechanisms at the basis of the sensing of humidity in the device were investigated by cyclic voltammetry and rationalized by reversible binding and extraction of water ions from the volume of the keratin active layer, while the figures of merit of the biopolymer such as the ionic conductivity and relaxation time were determined by means of electrical impedance and dielectric relaxation spectroscopy. A reliable linear correlation between the controlled-humidity level and the amperometric output signal together with the assessment on measure variance are demonstrated. Collectively, the fine-tuned ionic-electrical characterization and the validation in controlled conditions of the free-standing insoluble all-keratin made microelectrode array ionic sensor pave the way for the effective use of keratin biopolymer in wearable or edible electronics where conformability, reliability and biocompatibility are key-enabling features.

To begin understanding how pulsed infrared light modulates brain tissues in vivo, we explored its effects on isolated cortical astrocytes in vitro. Pulsed IR light may be a useful tool to study glial physiology.

Natural biomaterials are more and more used for the development of high technology solutions, setting the scene for a bio-based material economy that responds to the increasing demand of environmentally friendly products. Among natural biomaterials, silk fibre protein called silk fibroin (SF) produced by the Bombyx mori L. insect, recently found a broad range of applications in biomedical field. SF substrates display remarkable properties like controlled biodegradability, flexibility, mechanical resistance and optical transparency, solution processability. These properties combined with the water-based extraction and purification process make SF a promising material for sustainable manufacturing enabling to partially replace synthetic, plastic-based and non-biodegradable material use. The use of SF interfaces in biocompatible electronic or photonic devices for advanced biomedical applications has been recently highlighted. However, the use of a natural biomaterial is challenging due to the complex nature of the biological molecule, and it requires to tightly control biomaterial properties during all the manufacturing steps. In this work, we show the results obtained by in loco production of raw-material, defining the best condition for silkworm selection and growth. The assessment and standardization of extraction/purification methodology are reported with reference to the high purity and remarkable performance in terms of chemo-physical property and biocompatibility of the obtained SF products. Finally, we demonstrate the fabrication, characterization and validation of microfluidic and photonic components of a lab-on-a-chip device for biodiagnostic based on biomanufactured SF.

This work describes the preparation of a novel substrate based on keratin extracted from wool and its application as potential support for solution-processed organic solar cells. Optically transparent, free-standing, and resistant keratin films are successfully prepared, starting from water solution, and characterized in terms of morphology, structure, thermal and mechanical properties. The effect of solvents and thermal annealing is also investigated in order to mimic and evaluate the impact of the processing conditions used for devices fabrication. Thermally annealed keratin films exhibit enhanced optical transparency (>87%) in the visible region of the spectrum, a transition from alpha-helix to beta-sheet and turn structures, improved thermal stability and Young's modulus. The good transparency, flatness, and resistance of as-cast substrates allow the successful preparation of organic solar cells. Photovoltaic performances similar to those reported for other natural/biobased supports are achieved, confirming the potential of keratin film as an alternative and promising support material for eco-friendly, fully printable, sustainable, and inexpensive optoelectronic devices.

Increasing evidences are demonstrating that structural and functional properties of non-neuronal brain cells, called astrocytes, such as those of cytoskeleton and of ion channels, are critical for brain physiology. Also, changes in astrocytes structure and function concur to and might determine the outcome of neuronal damage in acute neurological conditions or of chronic disease. Thus, the design and engineering of biomaterials that can drive the structural and functional properties of astrocytes is of growing interest for neuroregenerative medicine. Poly-epsilon-caprolactone (PCL), is FDA-approved polyester having excellent mechanical and chemical properties that can be tailored to obtain neural implants for regenerative purposes. However, the study on the use of PCL substrates for neuroregenerative purposes are mainly aimed at investigating the interaction of the material with neurons. Here, we report on the long-term viability, morphology, structural and functional properties of primary astrocytes grown on electrospun fibres of PCL (-GEL) and on blending of PCL and Gelatin protein (+GEL). We found that topography and morphological features of the substrate are the properties that mainly drives astrocytes adhesion and survival, over the long term, while they do not alter the cell function. Specifically, aligned PCL fibres induced in astrocytes a dramatic actin-cytoskeletal rearrangement as well as focal adhesion point number and distribution. Interestingly, structural changes observed in elongated astrocytes are not correlated with alterations in their electrophysiological properties. Our results indicated that PCL electrospun fibres are a permissive substrate that can be tuned to selectively alters astrocytes structural components while preserving astrocytes function. The results open the view for the use of PCL based electrospun fibres to target astrocytes for the treatment of brain dysfunction such as injuries or chronical disease.

During the last decade, significant progress has been made in scaffold design for bone and nerve regeneration. The manipulation of material chemistry and processing technologies allows for improvement of structural and functional properties of tailor-made devices by the assembly of various materials combination or the ex novo synthesis of new materials with new functionalities (i.e., optical, electrical, magnetic), thus opening new and interesting routes for their application in tissue engineering. For instance, the manipulation of different materials may actively contribute to the design of highly complex platforms able to reproduce interface tissues such as meniscus, cartilage, and intervertebral disc, which also requires the re-invention/adaptation of conventional processing techniques for the fabrication of multilayered systems with chemical/physical gradients and multiple functionalities. Hence, it is mandatory to begin with a base of solid knowledge about material properties to properly design tailored scaffolds in order to optimize, case by case, repair and regeneration strategies. Generally, an ideal biomaterial should be biocompatible and bio-adhesive, possess adequate mechanical properties to tolerate the applied physiological load, and finally, show good bioactivity to ensure sufficient bonding at the material/tissue interface. The criteria for selecting the materials as biomaterials may be based on their chemistry, molecular weight, solubility, shape and structure, hydrophilicity/hydrophobicity, lubricity, surface energy, water absorption, and degradation properties. A strongly considered criteria to select a biomaterial for the development of 3D scaffolds is to match the mechanical properties and the degradation rate; this functions as a great opportunity to gradually support regeneration mechanisms as well as to release bioactive molecules and drugs by time and space controlled routes. In general, biodegradable/resorbable properties mainly refer to the susceptibility of a polymer to be decomposed by living organisms or by environmental factors. According to the ASTM (American Society for Testing and Materials) standard definition, biodegradable means “capable of undergoing decomposition into CO 2 , CH 4 , H 2 O, inorganic compounds or biomass”. In the restriction of tissue engineering use, biodegradable polymers have to be decomposed into biologically acceptable molecules—without the formation of harmful intermediate products—that can be metabolized and removed from the body via natural pathways (metabolism or excretion). Their ease of manufacturability, low cost, and customizable mechanical and physical properties make them useful for the fabrication of scaffolds by different processing techniques and modalities. Among biodegradable/bioresorbable polymers, it is possible to distinguish two different groups: natural and synthetic. The former one mainly includes proteins (i.e., collagens, zein, gelatin, elastin, silk fibroin) amides (i.e., starch) and polysaccharides (i.e., chitin, chitosan, alginates, cellulose derivates), which are macromolecules totally recognized in the biological microenvironment fully suitable for the regeneration of different tissues (i.e., nerve, cartilage, bone). Despite many advantages offered by materials from natural sources, notably biological recognition, synthetic polymers have often been preferred for their higher versatility in terms of properties’ variability and workability. In particular, relevant drawbacks in mechanical properties of natural polymers have imposed the use of synthetic ones to reach an acceptable balance between chemical stability and in vivo durability. However, many years of experimental studies have underlined that non-optimal cell interaction may be often an impenetrable limitation for the in vitro and in vivo applicability of scaffolds. Indeed, it is usually mandatory to assess chemical (i.e., molecular grafting) or physical (i.e., blending with natural polymers) modifications to generate their semi-synthetic counterparts, better recognized, even if not completely accepted into the implant site.

The use of doped silk fibroin (SF) films and substrates from Bombyx mori cocoons for green nanotechnology and biomedical applications has been recently highlighted. Cocoons from coloured strains of B. mori, such as Golden-Yellow, contain high levels of pigments that could have a huge potential for the fabrication of SF based biomaterials targeted to photonics, optoelectronics and neuroregenerative medicine. However, the features of extracted and regenerated SF from cocoons of B. mori Golden-Yellow strain have never been reported. Here we provide a chemophysical characterization of regenerated silk fibroin (RSF) fibers, solution, and films obtained from cocoons of a Golden-Yellow strain of B. mori, by SEM, (1) H-NMR, HPLC, FT-IR, Raman and UV-Vis spectroscopy. We found that the extracted solution and films from B. mori Golden-Yellow fibroin displayed typical Raman spectroscopic and optical features of carotenoids. HPLC-analyses revealed that lutein was the carotenoid contained in the fiber and RSF biopolymer from yellow cocoons. Notably, primary neurons cultured on yellow SF displayed a threefold higher neurite length than those grown of white SF films. The results we report pave the way to expand the potential use of yellow SF in the field of neuroregenerative medicine and provide green chemistry approaches in biomedicine.

Keratin (Ker) protein regenerated from readily available and low-cost wastes (e.g. raw wool, feathers and textile by-products) is a promising natural polymer for tissue engineering and drug delivery. Nevertheless, while showing good bioactivity and great drug carrier properties, keratin lacks of suitable mechanical characteristics. To overcome this drawback, keratin was blended with poly(butylene succinate) (PBS), a biodegradable and biocompatible polyester able to confer mechanical integrity to the keratin based materials. Despite the poor compatibility at the molecular level between keratin and PBS, their 50-50 blends were successfully electrospun into manageable mats, made of randomly oriented nanofibers with mean diameter of 290 nm. Along with mechanical properties, PBS improves also the thermal stability of the keratin based nanofibrous mats. On the other hand, compared to PBS-only electrospun mats, the presence of keratin improves both swelling ability and biodegradability and amplifies the capacity of diclofenac release as well as fibroblast proliferation of the blend mat.

reserved 10 si Fund for Investment in Basic Research (FIRB)–Futuro in Ricerca (RBFR12SJA8_001; RBFR12SJA8_002) This work was supported by grants from the University of Bologna (RFO2016/17; to M.C.) and the Italian Minister for Education, University, and Research within the FIRB–Futuro in Ricerca (to V.B. and G.P.N.). The U.S. Air Force Office of Scientific Research, Research Projects Advanced Nano-Structured Material Interfaces and Devices for InVivo-like–In Vitro Monitoring of Astrocytes Physiology and Brain Toxicology (ASTROMAT; FA9550 16 1 0502) and Shedding Light on Glial Function (ASTRONIR; FA9550-17-1-0502) (both to V.B.) Consolidated evidence indicates that astroglial cells are critical in the homeostatic regulation of cellular volume by means of ion channels and aquaporin-4. Volume-regulated anion channel (VRAC) is the chloride channel that is activated upon cell swelling and critically contributes to cell volume regulation in astrocytes. The molecular identity of VRAC has been recently defined, revealing that it belongs to the leucine-rich repeat-containing 8 (LRRC8) protein family. However, there is a lack of evidence demonstrating that LRRC8A underpins VRAC currents in astrocyte. Nonetheless, direct evidence of the role of LRRC8A in astrocytic regulatory volume decrease remains to be proved. Here, we aim to bridge this gap in knowledge by combining RNA interference specific for LRRC8A with patch-clamp analyses and a water-permeability assay. We demonstrated that LRRC8A molecular expression is essential for swelling-activated chloride current via VRAC in primary-cultured cortical astrocytes. The knockdown of LRRC8A with a specific short interference RNA abolished the recovery of the cell volume after swelling induced by hypotonic challenge. In addition, immunoblotting, immunofluorescence, confocal imaging, and immunogold electron microscopy demonstrated that LRRC8A is expressed in the plasma membrane of primary cortical astrocytes and in situ in astrocytes at the perivascular interface with endothelial cells. Collectively, our results suggest that LRRC8A is an essential subunit of VRAC and a key factor for astroglial volume homeostasis mixed Formaggio F, Saracino E, Mola MG, Rao SB, Amiry-Moghaddam M, Muccini M, Zamboni R, Nicchia GP, Caprini M, Benfenati V. Formaggio F, Saracino E, Mola MG, Rao SB, Amiry-Moghaddam M, Muccini M, Zamboni R, Nicchia GP, Caprini M, Benfenati V.

In this work novel hybrid materials for drug delivery purposes are obtained by combining keratin with hydrotalcite nanoparticles containing diclofenac. The hybrid films showed a less pronounced swelling, porosity and degradation and a greater thermal stability compared to pure keratin films containing free diclofenac. These results, together with the slight shift towards smaller wavelength numbers of amide I band led to the hypothesis of a probable cross-linking between hydrotalcites and the protein mediated by glutaraldehyde, which results in a total reinforcing action on the hybrid material. In addition, diclofenac release profiles of the hybrid film in physiological conditions were higher than those of the non-hybrid compound. Furthermore, keratin/hydrotalcite were able to support fibroblast cells adhesion and growth suggesting their potential use as drug delivery systems for wound healing and tissue engineering applications.

Organic bioelectronics have a huge potential to generate interfaces and devices for the study of brain functions and for the therapy of brain pathologies. In this context, increasing efforts are needed to develop technologies for monitoring and stimulation of nonexcitable brain cells, called astrocytes. Astroglial calcium signaling plays, indeed, a pivotal role in the physiology and pathophysiology of the brain. Here, the use of transparent organic cell stimulating and sensing transistor (O-CST) architecture, fabricated with N,N'-ditridecylperylene-3,4,9,10-tetracarboxylic diimide (P13), to elicit and monitor intracellular calcium concentration ([Ca2+](i)) in primary rat neocortical astrocytes is demonstrated. The transparency of O-CST allows performing calcium imaging experiments, showing that extracellular electrical stimulation of astrocytes induces a drastic increase in [Ca2+](i). Pharmacological studies indicate that transient receptor potential (TRP) superfamily are critical mediators of the [Ca2+](i) increase. Experimental and computational analyses show that [Ca2+](i) response is enabled by the O-CST device architecture. Noteworthy, the extracellular field application induces a slight but significant increase in the cell volume. Collectively, it is shown that the O-CST is capable of selectively evoking astrocytes [Ca2+](i), paving the way to the development of organic bioelectronic devices as glial interfaces to excite and control physiology of non-neuronal brain cells.

The basic principle of biomimicry is currently adopted in tissue engineering approach for the design of the majority of the three-dimensional (3D) scaffolds, both in terms of physicochemical properties, as well as bioactivity. Custom-made scaffold fabrication methodologies can be successfully used to manipulate biocompatible materials (synthetic and natural ones), thus assuring an improved performance of the scaffolds through an accurate design of matrix pores and degradation properties to fully match the specific requirements of natural tissue to be regenerated. However, extensive studies have highlighted some intrinsic limitation of synthetic polymers in terms of biological performance, thus requiring the need of tailored functionalization via bioactive molecules (i.e., proteins, growth factors). Hence, proteins of natural origin may represent the most attractive alternative to synthetic polymers, mainly due to their similarities with the extracellular matrix (ECM), chemical versatility as well as their excellent biocompatibility. This chapter aims at classifying the most interesting natural proteins suitable for the fabrication of three-dimensional porous scaffolds, by remarking main advantages in different biologically and clinically relevant applications.

Silk fibroin (SF) is a natural polymer of increasing interest for applications ranging from tissue engineering to optoelectronics. Here, we report a new mild and facile strategy targeted on hydroxylic pendants of serine and tyrosine residues, to functionalize SF in water, based on the use of amino(propyl)triethoxysilane (APTES), a common silylating agent. APTES is exploited as a bifunctional linker to bind SF through the triethoxysilane a-ends and to simultaneously graft species of interest, even hydrophobic ones, by means of the end g-amino groups. By using a fluorescent oligothiophene bearing amino reacting end groups (T3) we monitor the process simply through fluorescence detection and we demonstrate the value of the proposed method to achieve chemically modified SF materials. Moreover, we show that the new SF based biocomposite retains silk filmability and transparency but also shows T3 fluorescence and markedly enhanced mechanical robustness.

Silk fibroin is a natural protein that constitutes the core fibre of the silkworm cocoon. Recently, a great deal of attention is being paid to the use of the regenerated silk fibroin (RSF) solution that can be obtained by water-processing of the cocoon fibre. Indeed, thanks to its chemical and physical properties it has been shown that substrates obtained by RSF can be used as biomaterials for several biomedical and technological applications. In this context, silk fibroin could be exploited as raw material that can become a platform for eco-sustainable manufacturing. The project SILK.IT, coordinated by the CNR-ISOF, within the framework of the Flagship Project “Factory of the Future”, a research programme approved by the Interministerial Committee for Economic Planning (CIPE), aims to support this assumption by developing methods and protocols to use this silk fibroin as new material for advanced biotechnologies and sustainable manufacturing. The main goal of the project is to establish and control the whole-chain underpinning the silk fibroin-based technology, and to promote its up-scaling from the laboratory to industrial scale, targeting bio-photonics for biomedical application. The recent results obtained by the project are herein reported as key building block towards proposed achievement to establish a sustainable and process-controlled silk-based bio-manufacturing of the future.