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New insoluble layered zirconium phosphate carboxyaminophosphonates (ZPs), with the general formula Zr2(PO4)H5[(O3PCH2)2N(CH2)nCOO]2·mH2O (n = 3, 4, and 5), have been prepared and characterized. The crystal structure for n = 3 and 4 samples was determined ab initio from X-ray powder diffraction data. The structure for n = 3 was monoclinic in space group C2/c with the following unit cell parameters: a = 34.346(1) Å, b = 8.4930(2) Å, c = 9.0401(2) Å, and β = 97.15(1)°. The structure for n = 4 was triclinic in space group P1̅ with the following unit cell parameters: a = 17.9803(9) Å, b = 8.6066(4) Å, c = 9.0478(3) Å, α = 90.466(3)°, β = 94.910(4)°, and γ = 99.552(4)°. The two structures had the same connectivity as Zr phosphate glycine diphosphonate (n = 1), as previously reported. By intercalation of short amines, these layered compounds were exfoliated in single lamella or packets of a few lamellae, which formed colloidal dispersions in water. After a thorough characterization, the dispersed lamellae were functionalized with Ag nanoparticles, which were grown in situ on the surface of exfoliated lamellae. Finally, their antimicrobial activity was tested on several Gram-positive and Gram-negative bacteria. All of these systems were found to be active against the four pathogens most frequently isolated from orthopedic prosthetic infections and often causative of nosocomial infections. Interestingly, they were found to express powerful inhibitory activity even against bacterial strains exhibiting a relevant profile of antibiotic resistance such as Staphylococcus aureus ATCC 700699.

Skin disorders are widespread around the world, affecting people of all ages, and oxidative stress represents one of the main causes of alteration in the normal physiological parameters of skin cells. In this work, we combined a natural protein, fibroin, with antioxidant compounds extracted in water from pomegranate waste. We demonstrate the effective and facile fabrication of bioactive and eco-sustainable films of potential interest for skin repair. The blended films are visually transparent (around 90%); flexible; stable in physiological conditions and in the presence of trypsin for 12 days; able to release the bioactive compounds in a controlled manner; based on Fickian diffusion; and biocompatible towards the main skin cells, keratinocytes and fibroblasts. Furthermore, reactive oxygen species (ROS) production tests demonstrated the high capacity of our films to reduce the oxidative stress induced in cells, which is responsible for various skin diseases.

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.

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.

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.

Astrocytes play a critical role in regulating brain physiology at ionic, synaptic and whole-organ level. Their function is mainly controlled by ionic signalings, in particular Ca2+ signaling, that mediate cell-cell communication. Infrared pulsed stimulation is a label-free tool that has been previously used to modulate neuronal firing. Here we present the use of infrared pulsed light to stimulate ionic astrocytic signaling in order to modulate astroglial physiology. We present infrared pulsed stimulation as a powerful technique to understand astrocytic function and dysfunction.

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.

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.

A layered insoluble inorganic-organic solid, namely zirconium phosphate glycine-N,N-bismethylphosphonate, was used to prepare dispersions of nanosheets to support active metals such as metallic silver nanoparticles and zinc ions. Zr phosphate-phosphonate microcrystals were first exfoliated with methylamine to produce a stable colloidal dispersion and then the methylamine was removed by treatment with hydrochloric acid. The obtained colloidal dispersion of Zr phosphate-phosphonate nanosheets was used to immobilize silver or zinc cations, via ion exchange, with the acidic protons of the sheets. The layered matrix showed a great affinity for the metal cations up taking all the added cations. The treatment of the dispersions containing silver ions with ethanol yielded metal silver nanoparticles grafted on the surface of the layered host. The samples were characterized by X-ray powder diffraction, elemental analysis transmission electron microscopy, and selected samples were submitted to antimicrobial tests. The nanocomposites based on Ag nanoparticles showed good bactericidal properties against the bacterial reference strain Staphylococcus epidermidis (S. epidermidis).

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.

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.

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

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.

Histone deacetylases, HDACs, have been demonstrated to play a critical role in epigenetic signaling and were found to be overexpressed in several type of cancers; therefore, they represent valuable targets for anticancer therapy. 9-Hydroxystearic acid has been shown to bind the catalytic site of HDAC1, inducing G0/G1 phase cell cycle arrest and activation of the p21(wAF1) gene, thus promoting cell growth inhibition and differentiation in many cancer cells. Despite the (R) enantiomer of 9-hydroxystearic acid (9R) displaying a promising in vitro growth-inhibitory effect on the HT29 cell line, its scarce water solubility and micromolar activity require novel solutions for improving its efficacy and bioavailability. In this work, we describe the synthesis and in vitro biological profiling of 9R keratin nanoparticles (9R@ker) obtained through an in-water drug-induced aggregation process. The anticancer activity of 9R@ker was investigated in the HT29 cell line; the results indicate an increased fluidity of cell membrane and a higher intracellular ROS formation, resulting in an unexpected S phase cell cycle arrest (25% increase as compared to the control) induced by 9R@ker with respect to free 9R and an induction of cell death.

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.

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.

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.

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.

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.

Lysinated molecular organic semiconductors are introduced as valuable multifunctional platforms for neural cells growth and interfacing. Cast films of quaterthiophene (T4) semiconductor covalently modified with lysine-end moieties (T4Lys) are fabricated and their stability, morphology, optical/electrical, and biocompatibility properties are characterized. T4Lys films exhibit fluorescence and electronic transport as generally observed for unsubstituted oligothiophenes combined to humidity-activated ionic conduction promoted by the charged lysine-end moieties. The Lys insertion in T4 enables adhesion of primary culture of rat dorsal root ganglion (DRG), which is not achievable by plating cells on T4. Notably, on T4Lys, the number on adhering neurons/area is higher and displays a twofold longer neurite length than neurons plated on glass coated with poly-l-lysine. Finally, by whole-cell patch-clamp, it is shown that the biofunctionality of neurons cultured on T4Lys is preserved. The present study introduces an innovative concept for organic material neural interface that combines optical and iono-electronic functionalities with improved biocompatibility and neuron affinity promoted by Lys linkage and the softness of organic semiconductors. Lysinated organic semiconductors could set the scene for the fabrication of simplified bioorganic devices geometry for cells bidirectional communication or optoelectronic control of neural cells biofunctionality.

Silk is a natural fibre obtained from the Bombyx mori silkworm cocoons that can be used in a wide range of fields thanks to its inherent multifunctionality. Post-production steps are necessary to impart colour to the fibres to employ the material for optics and photonic applications, such as in fluorescence-based optofluidic devices in lab-on-a-chip realization. Here we present an intrinsically greener dyeing approach for fabricating naturally functionalized silk, where highly-fluorescent organic dyes with lasing properties are in vivo up-taken by silkworms once introduced in the artificial diet. A detailed photoluminescence spectroscopy investigation is implemented to test whether the dyes are effectively incorporated within the silk proteins, in correlation with the silkworm gland positions where proteins extraction is held. Light amplification characteristics are demonstrated in silk extracted from glands of silkworm fed with artificial diet doped with Rhodamine B dye.

A layered yttrium phosphonate based on N-(phosphonomethyl)glycine (H3L) and of formula Y(PO3CH2NHCH2COOH)(HPO3CH2NHCH2COOH) was synthesized in mild hydrothermal conditions. Its crystal structure was first determined by single-crystal X-ray diffraction. Then, the synthetic parameters were changed in order to reduce the particle size of the compound. The use of microwave (MW) irradiation during the synthesis allowed a) to obtain the compound in form of nanoparticles (NP) in the 50- 300 nm range dispersed in water, b) to strongly reduce the reaction time by a factor 150, and c) to successfully introduce into the structure small amounts of a luminescent ion like terbium(III) as an isomorphic substituent of yttrium(III). The obtained NP were used to prepare composite materials by dispersing them in poly(3,4-ethylenedioxythiophene):poly( styrenesulfonate) (PEDOT:PSS). The resulting optical, photophysical, morphological and electrical properties of modified and pristine PEDOT:PSS films were investigated and compared, in order to test the potential use of Y(H2L)(HL) NP as luminescent downshifting materials in optoelectronic devices.

One of the main goals of nanomedicine in cancer is the development of effective drug delivery systems, primarily nanoparticles. Survivin, an overexpressed anti-apoptotic protein in cancer, represents a pharmacological target for therapy and a Molecular Beacon (MB) specific for survivin mRNA is available. In this study, the ability of polymethylmethacrylate nanoparticles (PMMA-NPs) to promote survivin MB uptake in human A549 cells was investigated. Fluorescent and positively charged core PMMA-NPs of nearly 60 nm, obtained through an emulsion co-polymerization reaction, and the MB alone were evaluated in solution, for their analytical characterization; then, the MB specificity and functionality were verified after adsorption onto the PMMA-NPs. The carrier ability of PMMA-NPs in A549 was examined by confocal microscopy. With the optimized protocol, a hardly detectable fluorescent signal was obtained after incubation of the cells with the MB alone (fluorescent spots per cell of 1.90 ± 0.40 with a mean area of 1.04 ± 0.20 µm2), while bright fluorescent spots inside the cells were evident by using the MB loaded onto the PMMA-NPs. (27.50 ± 2.30 fluorescent spots per cell with a mean area of 2.35 ± 0.16 µm2). These results demonstrate the ability of the PMMA-NPs to promote the survivin-MB internalization, suggesting that this complex might represent a promising strategy for intracellular sensing and for the reduction of cancer cell proliferation.

A critical factor for controlling serum albumin binding is surface hydrophobicity, which in turn decreases the cellular uptake of gold nanoparticles. Hydrophobic nanoparticles bind albumin more tightly, inhibiting particle uptake, with a direct correlation observed between uptake and surface hydrophobicity.

Nanosized hydrotalcite-like compounds (HTlc) with different chemical composition were prepared and used to study protein adsorption. Two soft proteins, myoglobin (Mb) and bovine serum albumin (BSA), were chosen to investigate the nature of the forces controlling the adsorption and how these depend on the chemical composition of the support. Both proteins strongly interact with HTlc exhibiting in most cases a Langmuir-type adsorption. Mb showed a higher affinity for Nickel Chromium (NiCr-HTlc) than for Nickel Aluminum (NiAl-HTlc), while for BSA no significant differences between supports were found. Adsorption experiments in the presence of additives showed that proteins exhibited different types of interactions onto the same HTlc surface and that the adsorption was strongly suppressed by the addition of disodium hydrogen phosphate (Na 2 HPO 4 ). Atomic force microscopy images showed that the adsorption of both proteins onto nanoparticles was followed by the aggregation of biocomposites, with a more disordered structure for BSA. Fluorescence measurements for adsorbed Mb showed that the inorganic nanoparticles induced conformational changes in the biomolecules; in particular, the interactions with HTlc surface quenched the tryptophan fluorescence and this process was particularly efficient for NiCr-HTlc. The adsorption of BSA onto the HTlc nanoparticles induced a selective quenching of the exposed fluorescent residues, as indicated by the blue-shift of the emission spectra of tryptophan residues and by the shortening of the fluorescence decay times.

Hydrotalcite nanocrystals doped with Eu(III) ions were prepared by the microemulsion method. XRPD measurements revealed that europium ions are very likely incorporated in a low-symmetry hydrotalcite-type layer. TEM and AFM imaging indicated that nanocrystals have a 150 nm width and a plate shape. Luminescence measurements showed that the doped powder is luminescent and the Eu(III) ions are located in a low symmetry site.

Mussel-inspired polydopamine (PD) coating represents a promising route for constructing functional materials and finely tuning or completely changing their surface properties. In this work, a mild and effective method to realize the deposition of PD on keratin-based films is reported. Reactive oxygen species (ROS), generated by keratin films doped with a photosensitizer, e.g., Azure A (AzA), upon UV-vis and vis-near IR irradiation, are exploited to obtain the PD coating. Interestingly, the use of vis-near IR irradiation leads to an increased production of ROS by AzA resulting in a greater PD deposition. Compared to uncoated keratin films, the PD-keratin coated materials show a granular but homogeneous surface and an increased hydrophilicity, maintaining the ROS generation ability of AzA. This work demonstrates a useful method to effectively and rapidly functionalize with PD materials that are sensitive to temperature, pH and UV light, such as keratin. The proposed strategy allows obtaining new multifunctional biomaterials of potential interest in tissue engineering and drug delivery; in particular, the use of PD-keratin films for near IR laser bonding of ophthalmic tissue, which is a representative case in wound healing purpose, is shown.

The adsorption of myoglobin (Mb) onto nanosized nickel aluminum hydrotalcite (NiAl-HTlc) surface was studied, and the structural properties of the resulting protein layer were analyzed by using FT-IR, Raman, and fluorescence spectroscopies. Upon adsorption onto the nanoparticle surface, the protein molecules maintained their secondary structure, while the tertiary structure was altered. The fluorescence spectra and anisotropy values of adsorbed Mb revealed that the emitting amino acid residues are affected by different microenvironments when compared to the native protein behavior. Moreover, the decrease of fluorescence decay times of tryptophan indicated the occurrence of interactions among the fluorophores and the constituents of the nanoparticles, such as the metal cations, which can take place when conformational changes of Mb occur. Raman spectra indicated that the interaction of Mb molecules with NiAl-HTlc nanoparticles modified the porphyrin core, changing the spin state of the heme iron from high spin (HS) to low spin (LS). The enzymatic activity of the nanostructured biocomposite was evaluated in the oxidation of 2-methoxyphenol by hydrogen peroxide and discussed on the basis of structural properties of adsorbed myoglobin.

A water-in-oil microemulsion made up of a cetyltrimethylammonium bromide/n-butanol/isooctane/MII and AlIII nitrate aqueous solution (MII = Mg or Ni or Zn) has been mixed with a microemulsion of the same composition but containing an ammonia solution instead of a metal nitrate solution. Collisions between the reverse micelles containing an MII and AlIII solution and those containing an NH3 solution form short-lived dimers that act as reaction vessels and control the nucleation and growth of MgAl, NiAl or ZnAl hydrotalcite-like compounds (HTlcs). The double water-in-oil microemulsion technique yields colloidal dispersions of nanoparticles whose size and shape were examined by transmission electron microscopy (TEM) and atomic force microscopy (AFM). The colloidal particles were between 50 and 100 nm depending on the composition of the microemulsions (water-to-surfactant and oil-to-water molar ratios). The separation of the nanoparticles from the reaction medium produces a gel made up of surfactant-free particles. HTlc nanocrystals were recovered from the gel (reaction medium), washed, and dried. They were then studied by chemical and thermogravimetric analyses, X-ray powder diffraction, N2-adsorption and BET surface analysis and scanning electron microscopy (SEM). The AlIII/(MII + AlIII) molar ratio of the recovered HTlc nanocrystals was between 0.24 and 0.29, and the basal spacing was about 8 A, a value in agreement with the presence of charge compensating bromide anions in the interlayer region. The proposed technique allows for HTlc nanocrystals to be obtained with a relatively high surface area with values ranging between 50 and 110 m2/g. The SEM analyses show that the nanoparticles are aggregated to give rise to complex spherical or rod-shaped microstructures.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

A study of the umbrella motion of the methyl cation, radical, and anion molecules is presented. This is the floppiest mode of vibration of all three species and its characterization is of fundamental importance for understanding their reactivity. Minimum Energy Paths of the umbrella motions according to the hyperspherical treatment were obtained, by single point calculations, at the CCSD(T)/aug-cc-pVQT level of theory in the Born-Oppenheimer approximation. These energy profiles permit us to calculate the vibrational levels through the Hyperquantization algorithm, which is shown appropriated for the description of the umbrella motion of these three molecules. The adiabatic electron affinity and ionization potentials were estimated to good accuracy. Partition functions are also calculated in order to obtain information on the reaction rates involving these groups.

The main purpose of the present work is to characterize the umbrella inversion motion of the CH- 3 , CH3 and CH- 3 molecules as a function of the environmental conditions. In particular, for the three investigated species we have studied how temperature affects times for umbrella inversion modes and their propagation velocity. These data are used to predict the statistical behavior of the reactions involving the AB3 like molecules and to relate the umbrella potential with the rate constants. The second aspect of this study concerns the molecular distribution charges as a function of the umbrella opening angle and of the total charge. The results have been used to calculate the induced electric field on a probe charge located at a given position perpendicular to the plane of the hydrogen atoms which is the most relevant for the reaction. Obtained values are presented as a function of the umbrella opening angle.

This work describes the preparation of keratin and chlorin e6-conjugated keratin nanoparticles, KNPs and KNPs@Ce6 respectively, by comparing self-assembling and desolvation methodologies. Nanoparticles were characterized in terms of yield, size, morphology, Ce6 loading ratio and ability to produce reactive oxygen species (ROS) upon irradiation with white light. Overall, both methods provided nanoparticles of comparable dimensions, morphology and Ce6 loading ratio. KNPs@Ce6 obtained by a self-assembling procedure were able to produce ROS in a concentration and irradiation-time dependent manner, while displaying compelling evidence of their photostability. In vitro internalization and photo-toxicity studies were performed on osteosarcoma (U2OS) and glioblastoma (U87) cells lines to assess the ability of KNPs@Ce6 nanoparticles to act as delivery systems for photodynamic therapy of cancer. Importantly, at all the Ce6 considered concentrations, e.g. 0.5, 2.5 and 5.0 μg mL−1, no dark toxicity was detected while the amount of Ce6 inside the cells, significantly increased when loaded onto KNPs. The irradiation of tumor cells loaded with KNPs@Ce6 resulted in a greater cell death percentage (approximately 90%) as compared to free Ce6 in both cell types and at all the considered concentrations, thus showing KNPs as effective and promising delivery vehicles for photodynamic therapy applications.

Pt electrodes coated with a Ni/Al or Ni/Fe layered double hydroxide (LDH) were studied to investigate whether the presence of Fe and the extent of crystallinity affect the performance of the Ni centers as redox mediators for oxidizable compounds. The LDHs were synthesized by both a chemical and an electrochemical method, which allowed the obtainment of thin and well-adherent LDH films having similar morphology but a different crystallinity degree. Fe centers were not electroactive but they influenced the electroactivity of Ni, shifting the redox potential to less anodic values and increasing the percentage of the electroactive Ni sites. The LDHs prepared by electrodeposition were more conductive than the chemically synthesized LDHs, and, when Fe was the trivalent metal, the electronic conductivity was further increased. The highest electrocatalytic efficiency, evaluated taking glucose as model compound, was obtained for the electrodes coated with the electrochemically synthesized LDHs.

We report the design, synthesis and structure-property investigation of a new perylene diimide material (PDI-Lys) bearing lysine end substituents. Water processed films of PDI-Lys were prepared and their self-assembly, morphology and electrical properties in both inert and air environments were theoretically and experimentally investigated. With the aim of evaluating the potential of PDI-Lys as a biocompatible and functional neural interface for organic bioelectronic applications, its electrochemical impedance as well as the adhesion and viability properties of primary neurons on the PDI-Lys films were studied. By combining theoretical calculations and electrical measurements we show that due to conversion between neutral and zwitterionic anions, the PDI-Lys film conductivity increased significantly upon passing from air to an inert atmosphere, reaching a maximum value of 6.3 S m-1. We also show that the PDI-Lys film allows neural cell adhesion and neuron differentiation and decreases up to 5 times the electrode/solution impedance in comparison to a naked gold electrode. The present study introduces an innovative, water processable conductive film usable in organic electronics and as a putative neural interface.