Inspired by the powerful photosensitizing properties of the red hair pigments pheomelanins, a photoresponsive cysteine-containing variant of the adhesive biopolymer polydopamine (pDA) is developed via oxidative copolymerization of dopamine (DA) and 5-S-cysteinyldopamine (CDA) in variable ratios.Chemical and spectral analysis indicate the presence of benzothiazole/benzothiazine units akin to those of pheomelanins. p(DA/CDA) copolymers displayimpedance properties similar to those of biological materials and a marked photoimpedance response to light stimuli. The use of the p(DA/CDA) copolymerto implement a solution-processed hybrid photocapacitive/resistive metalinsulator- semiconductor (MIS) device disclosed herein is the fi rst example oftechnological exploitation of photoactive, red-hair-inspired biomaterials as soft enhancement layer for silicon in an optoelectronic device. The bio-inspiredmaterials described herein may provide the active component of new hybrid photocapacitive sensors with a chemically tunable response to visible light.

N-functionalization of 5,6-dihydroxyindole with a hydrophilic triethyleneglycol (TEG) chain provides access to a new class of water-soluble eumelanin-like materials with relatively high dielectric constant and polyelectrolyte behaviour, reflecting enhanced charge transport by in-depth incorporation of hydration networks.

Diatoms microalgae can be regarded as living factories producing nanostructured and mesoporous biosilica shells (frustules) having a highly ordered hierarchical architecture. These unique, morphological, chemical and mechanical properties make diatoms' biosilica a very attractive nanomaterial for a wide variety of applications. Methods of purification of frustules that preserve their nanostructured morphology have been set up as well as in vivo or in vitro chemical modification protocols of the biosilica with functional molecules to generate biohybrid active materials for photonics, sensing, drug delivery and electronics. Herein we describe, with some selected examples, the great variety of applications envisaged for native and modified frustules, highlighting the material scientists' benefit to avail of nature in the construction of highly ordered biohybrid architectures for nanotechnology. New concepts for the biotechnological production of nanomaterials are opened by the use of diatoms as living factories.

Biosilica from living diatom microalgae has recently attracted the interest of the scientific community and found several applications in bio-nanotechnology. Among silica-maker organisms, diatom microalgae represent the most attractive marine microorganisms, featuring highly hierarchical, nanotextured and porous silica walls. These biologic structures, known as "frustules" are also chemically addressable via simple chemical synthesis. In this work, we propose new diatom-based hybrid materials consisting of biosilica extracted from living Thalassiosira weissflogii coated with polydopamine (PDA) films. The adhesion properties of the PDA were exploited to decorate the silica surface with silver nanoparticles. These multifunctional heterostructures can be useful for applications ranging from bioelectronics to biomedicine.

Nanostructured biosilica produced by Thalassiosira weissflogii diatoms is covalently functionalized with the cyclic nitroxide 2,6,6-tetramethylpiperidine-N-oxyl (TEMPO), an efficient scavenger of reactive oxygen species (ROS) in biological systems. Drug delivery properties of the TEMPO-functionalized biosilica are studied for Ciprofloxacin, an antimicrobial thoroughly employed in orthopedic or dental implant related infections. The resulting TEMPO-biosilica, combining Ciprofloxacin drug delivery with anti-oxidant properties, is demonstrated to be a suitable material for fibroblasts and osteoblast-like cells growth.

Diatoms microalgae produce biosilica nanoporous rigid outershells called frustules that exhibit an intricate nanostructured pore pattern. In this paper two specific Thalassiosira weissflogii culture conditions and size control procedures during the diatoms growth are described. Data from white field and fluorescence microscopy, evaluation of cell densities and cell parameters (k value and R value) according to cell culture conditions are listed. Different cleaning procedures for obtaining bare frustules are described. In addition, FTIR and spectrofluorimetric analyses of cleaned biosilica are shown. The data are related to the research article"Chemically Modified Diatoms Biosilica for Bone Cell Growth with Combined Drug-Delivery and Antioxidant Properties" [1].

This data article is related to our recently published research paper "Exploiting a new glycerol-based copolymer as a route to wound healing: synthesis, characterization and biocompatibility assessment", De Giglio et al. (Colloids and Surfaces B: Biointerfaces 136 (2015) 600-611) [1]. The latter described a new copolymer derived from glycerol and tartaric acid (PGT). Herein, an investigation about the PGT-ciprofloxacin (CIP) interactions by means of Fourier Transform Infrared Spectroscopy (FT-IR) acquired in Attenuated Total Reflectance (ATR) mode and Differential Scanning Calorimetry (DSC) was reported. Moreover, CIP release experiments on CIP-PGT patches were performed by High Performance Liquid Chromatography (HPLC) at different pH values.

Eumelanin-type biopolymers have attracted growing interest in the quest for soft bioinspired functional materials for application in organoelectronics. Recently, a metal-insulator-semiconductor device with a good quality interface was produced by spin coating of a commercial synthetic eumelanin-like material on a dry plasma-modified silicon surface. As a proof-of-concept step toward the design and implementation of next-generation eumelanin-inspired devices, we report herein an expedient chemical strategy to bestow n-type performance to polydopamine, a highly popular eumelanin-related biopolymer with intrinsic semiconductor behaviour, and to tune its electrical properties. The strategy relies on aerial co-oxidation of dopamine with suitable aromatic amines, e.g. 3-aminotyrosine or p- phenylenediamine, leading to good quality black polymeric films. Capacitance-voltage experiments on poly(dopamine/3-aminotyrosine) and poly(dopamine/p-phenylenediamine)-based metal insulator semiconductor devices on p-Si indicated a significant increase in flat band voltage with respect to polydopamine and previous synthetic eumelanin-based diodes. Variations of the flat band voltage under vacuum were observed for each device. These results point to polydopamine as a versatile eumelanin-type water-dependent semiconductor platform amenable to fine tuning of its electronic properties through incorporation of p-conjugating aromatic amines to tailor functionality.

tThe use of biocompatible materials based on naturally derived monomers plays a key role in pharma-ceutical and cosmetic industries. In this paper we describe the synthesis of a new low molecular weightcopolymer, based on glycerol and l-tartaric acid, useful to develop biocompatible dermal patches withdrug delivery properties. The copolymer's chemical composition was assessed by FT-IR (Fourier trans-form infrared spectroscopy),1H NMR (1H Nuclear Magnetic Resonance) and XPS (X-ray photoelectronspectroscopy), while its molecular weight distribution was estimated by SEC (size exclusion chromatog-raphy). Copolymer thermal properties were studied by TGA (thermogravimetric analysis). Biologicalevaluations by MTT assay and SEM (scanning electron microscopy) observations performed with murinefibroblasts and human keratinocytes (HaCaT) revealed a good compatibility of the proposed copolymer.Ciprofloxacin was selected as model drug and its release was evaluated by HPLC (high performance liquidchromatography), showing that the new copolymer supplied promising results as drug delivery systemfor wound healing applications. Furthermore, investigations on Skin-Mesenchymal stem cells (S-MSCs)behaviour and gene expression showed that the copolymer and its combination with ciprofloxacin didnot affect their stemness. In this regard, the fabrication of dermal patches with new, low cost materials forlocal treatment of skin infections represents an attractive strategy in order to bypass the worrying sideeffects of systemic antibiotic therapy. Overall, the performed physico-chemical characterization, drugrelease test and biological evaluations showed that this new copolymer could be a promising tool for thein situ delivery of bioactive molecules during skin lesions treatment.

Over the past decade synthetic melanins, melanin-like polymers and melanin-based copolymers have been the focus of growing attention as soft biocompatible functional materials for engineering high performance, low cost optoelectronic devices, such as memory devices, light emitting diodes and field effect transistors. The unique combination of physicochemical properties of melanins, such as broad band absorption in the UV-visible range, intrinsic free radical character, water-dependent hybrid ionic-electronic conductor behaviour and excellent biocompatibility, have inspired use of melanic polymers as valuable functional materials for organic bioelectronics. However, several gaps and issues still hinder rapid progress of melanin-based organic electronics and bioelectronics, including in particular the limited contribution of electronic conductivity and current decay with time under biasing. The aim of this paper is to provide an overview of the structural and optoelectronic properties of melanins and to bring to focus current gaps and challenges in the development of melanin-based materials for bioelectronics. Starting from commercial samples, the paper surveys different melanin-type materials with special emphasis on the potential of polydopamine (pDA), a highly adhesive mussel-inspired melanin-type platform, for incorporation in optoelectronic devices. Simple chemical tailoring procedures for engineering pDA-based n-type polymers and photoresponsive materials for photocapacitive sensors are eventually illustrated.

Starting from polydisperse diatomaceous earth (DE), we proposed an efficient separation method for obtaining different morphologies of biosilica from diatoms. DE is a very low-cost source of silica containing all the differently nanostructured elements. By a glucose gradient/dialysis, three types of biosilica morphologies were achieved: rods, valves, and clusters. We fully characterized the diatom fractions and we used them to produce fluorescent biosilica platforms (tabs). These supports exhibited good resistance in water, ethanol, and soft scraping. A preliminary biologic application by testing Saos-2 proliferation was also performed to check osteoblasts-like cells biologic attitude for this scaffolds with tunable nanostructure.

Early diagnosis of plant virus infections before the disease symptoms appearance may represent a significant benefit in limiting disease spread by a prompt application of appropriate containment steps. We propose a label-free procedure applied on a device structure where the electrical signal transduction is evaluated via impedance spectroscopy techniques. The device consists of a droplet suspension embedding two representative purified plant viruses i.e.,Tomato mosaic virus and Turnip yellow mosaic virus,put in contact with a highly hydrophobic plasma textured silicon surface. Results show a high sensitivity of the system towards the virus particles with an interestingly low detection limit,from tens to hundreds of attomolar corresponding to pg/mL of sap,which refers,in the infection time-scale,to a concentration of virus particles in still-symptomless plants. Such a threshold limit,together with an envisaged engineering of an easily manageable device,compared to more sophisticated apparatuses,may contribute in simplifying the in-field plant virus diagnostics.

Palladium-promoted homocoupling reaction of vinyl- and polyenylsilanes in aqueous conditions has been investigated. The reaction is catalyzed by PdCl(2) in the presence of the re-oxidizing system CuCl(2)/LiCl and occurs at room temperature in aqueous solutions containing nonionic amphiphiles. Symmetrically alpha,omega-disubstituted stereodefined all-trans polyenes have been obtained in mild conditions and in good yields (65-87%), higher than those previously reported for the same reactions carried out in methanol or HMPA. A comparison between two commercially available surfactants, Triton X-100 and PTS, has been performed.

Biotechnological processes harnessing living organisms' metabolism are low-cost routes to nanostructured materials for applications in photonics, electronics, and nanomedicine. In the pursuit of photonic biohybrids, diatoms microalgae are attractive given the properties of the porous micro-to-nanoscale structures of the biosilica shells (frustules) they produce. The investigations have focused on in vivo incorporation of tailored molecular fluorophores into the frustules of Thalassiosira weissflogii diatoms, using a procedure that paves the way for easy biotechnological production of photonic nanostructures. The procedure ensures uniform staining of shells in the treated culture and permits the resulting biohybrid photonic nanostructures to be isolated with no damage to the dye and periodic biosilica network. Significantly, this approach ensures that light emission from the dye embedded in the isolated biohybrid silica is modulated by the silica's nanostructure, whereas no modulation of photoluminescence is observed upon grafting the fluorophore onto frustules by an in vitro approach based on surface chemistry. These results pave the way to the possibility of easy production of photonic nanostructures with tunable properties by simple feeding the diatoms algae with tailored photoactive molecules.

Hysteresis behaviour of the current-voltage characteristics collected on spin coated synthetic eumelanin layer embedded in the Au/eumelanin/ITO/glass structure is shown. The effect has been observed under dark both in air and vacuum environment and its magnitudehas been found related to the eumelanin hydration state. Moreover, in vacuum and under white light illumination, enhancement of the hysteresis loop area respect to those collected under dark has been observed. Space charge storage and charge trapping/detrapping as possible mechanisms responsible of the observed current-voltage behaviour are discussed. Preliminary experimental results have evidenced the possible integration of eumelanin layers in electro-optical charge storage based memory devices.

The chemical decoration of biosilica shells (frustules) from microalgae with several classes of organic molecules is a convenient, scalable biotechnological route to silica nanostructures with applications ranging from photonics to biomedicine. Here we report for the first time the in vivo staining of Thalassiosira weissflogii diatoms with a two photon red emitting triphenylamine-based fluorescent dye bearing a triethoxysilyl functional group (tPhA-Silane). In vivo staining of the cells has been investigated with confocal microscopy and hybrid silica structures comprising the dye embedded into the biosilica have been isolated by proper protocols able to remove the organic protoplasm.

Diatoms microalgae represent a natural source of highly porous biosilica shells (frustules) with promising applications in a wide range of technological fields. Functionalization of diatoms' frustules with tailored luminescent molecules can be envisaged as a convenient, scalable biotechnological route to new light emitting silica nanostructured materials. Here we report a straightforward protocol for the in vivo modification of Thalassiosira weissflogii diatoms' frustules with a red emitting organic dye based on thienyl, benzothiadiazolyl and phenyl units. The metabolic insertion of the dye molecules into the diatoms shells, combined with an acidic-oxidative isolation protocol of the resulting dye stained biosilica, represents a novel strategy to develop highly porous luminescent biosilica nanostructures with promising applications in photonics.

Synthetic melanin based metal-insulator-semiconductor devices are fabricated for the first time thanks to silicon surface wettability modification by using dielectric barrier discharge plasma. Ambipolar charge trapping in air and ion drift mechanisms under vacuum are identified by capacitance-voltage hysteresis loops. These results aim to foresee the possible integration of synthetic melanin layers as a novel capacitor in organic polymer based devices.

The electrical transport across a biomimetic interface made up of spin coated melanin layers on nanotextured silicon surfaces with different texturing features and wetting properties is discussed. Nanotexturing allows, under certain conditions, the melanin to anchor better on a hydrophobic silicon surface, overcoming the hydrophilic melanin-hydrophobic silicon interface issue. The feature of the electrical signal transduction across such a structure was studied by impedance spectroscopy and found to be influenced by the nano-texturing chemistry and surface morphology. The effects of a voltage pulse, as external stimulus modifying the electrical transport mechanisms, and retention of the subsequently achieved carrier transport conditions have been elucidated. The results suggest a possible exploiting of this circuit element for bio and environmental molecules' sensing.

The memory-like behavior of melanin biopolymer under electrical stimuli is shown throughelectrical transport characterization performed on melanin based metal insulator semiconductorstructures on silicon. The presence of a memory window and retention behavior is verified bycapacitance-voltage read outs before and after the application of voltage pulses. Interestingly, thesephenomena occur without the presence of metallic nanoclusters enclosed in the melanin matrix.Charge trapping is considered the main mechanism responsible for the melanin memory-likecharacter. The inability to erase the memory window has been ascribed to the permanentpolarization effect during the application of the voltage pulse.

Diatoms are unicellular photosynthetic microalgae, ubiquitously diffused in both marine and freshwater environments, which exist worldwide with more than 100 000 species, each with different morphologies and dimensions, but typically ranging from 10 to 200 µm. A special feature of diatoms is their production of siliceous micro- to nanoporous cell walls, the frustules, whose hierarchical organization of silica layers produces extraordinarily intricate pore patterns. Due to the high surface area, mechanical resistance, unique optical features, and biocompatibility, a number of applications of diatom frustules have been investigated in photonics, sensing, optoelectronics, biomedicine, and energy conversion and storage. Current progress in diatom-based nanotechnology relies primarily on the availability of various strategies to isolate frustules, retaining their morphological features, and modify their chemical composition for applications that are not restricted to those of the bare biosilica produced by diatoms. Chemical or biological methods that decorate, integrate, convert, or mimic diatoms' biosilica shells while preserving their structural features represent powerful tools in developing scalable, low-cost routes to a wide variety of nanostructured smart materials. Here, the different approaches to chemical modification as the basis for the description of applications relating to the different materials thus obtained are presented.

Palladium-promoted cross-dimerization reaction of alkenylsilanes is reported for the first time, which is also one of the very first studies on oxidative cross-coupling between vinylic organometallic reagents. The reaction occurs at room temperature in aqueous micelles and represents a convenient access to all-trans push-pull butadienes. © 2013 Elsevier B.V. All rights reserved.

Photosynthetic Reaction Center (RC) is a transmembrane photoenzyme capable of converting absorbed photons into electron-hole pairs with almost unitary efficiency. The unique properties of this natural photoconverter attract considerable interest for its use as functional component in nanomaterials and bioelectronics devices. Implementation of RC into nanostructures or anchoring on devices' electrode surfaces require the development of suitable chemical manipulation. Here we report our methods to embed this protein in soft nanostructures or to covalently attach it on surfaces without denaturating it or altering its chemical properties. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

The integration of biopolymers into hybrid electronics is one of the up to date issues in view of the achievement of fully bio-compatible devices. Among 'hot topics' in bio-polymer research, synthetic melanin or, briefly, "melanin", has been recently recognized as a quite intriguing macromolecule thanks to its multifunctional optoelectronic properties. To date, melanin transport properties have been mainly enlightened on pellets, while optical absorption and conductivity properties have been investigated on melanin layers deposited on quartz and indium tin oxide/glass. The unavailability of suitable procedures to improve or promote adequate self assembling of melanin layer deposition onto substrate of interest in organic and solid state electronics (hybrid) like silicon substrates, prevent interesting studies on such structures. The reason stems basically on the difference between the hydrophilic nature of the melanin and the hydrophobic one of the supports (mostly of silicon). However, our group solved this issue and was able to tailor a melanin based metal/insulator/metal and metal/insulator/silicon structures, where synthetic melanin was embedded as the insulating part. This allowed to disclose interesting features related to data storage capabilities of melanin layers deposited on indium tin oxide/glass and silicon never investigated so far. In this work we show an overview on our recent mentioned results, and particular attention is paid on structures on silicon substrates. The use of pSi and nSi substrates and measurements under different environment conditions has enabled to gain insight into ambipolar electrical transport mechanisms, still unexplored. These results constitute a first important basic insight into melanin-based bio inspired structures and represent a significant step towards their integration in several kinds of hybrid organic polymer-based devices.

Nanostructured biosilica extracted from diatoms are extensively exploited in a wide number of applications including photonics, biosensing, and drug delivery.[1] Very recently diatoms biosilica has been investigated as smart multifunctional biomaterial for cell growth.[2] Based on these results, we focused on the in vivo engineering of diatoms frustules with sodium alendronate, an osteoclasts inhibitor and a bone cells proliferation enhancer. The obtained doped frustules could be developed as multifunctional scaffolds able to promote osteoblast cells adhesion and proliferation (Fig. 1). in vivo doped with sodium alendronate (NaAl ).

Xylella fastidiosa (Xf) is a xylem-limited bacterium, regulated as a quarantine pest, that is causing a devastating disease on olive crops in the southern area of Apulia (Italy) and whose potential spread in the Mediterranean area poses a severe threat to EU agri- culture and landscape environment. Xf virulence is related to the expression of a cluster of rpf (regulation of pathogenicity factors) genes responsible for a signalling system based on small fatty acid molecules called DSF (Diffusible Signalling Factor). Since DSF regulation is involved in pathogenicity traits of Xf and biofilm for- mation, a "pathogen-confusion" strategy, based on the alteration of DSF levels in planta, has been proposed to contrast bacterial infection. In grapevine, the strategy is based on the transgenic ex- pression of the rpfF gene, which encodes the DSF-synthase. We are attempting to express the rpfF gene of the olive-infecting Xf strain CoDiRO in the heterologous Escherichia coli system. The gene product has been successfully detected by Western blot analysis in cell protein extracts. Chemical characterisation by Gas Chromatog- raphy-Mass Spectrometry analysis of the DSF molecules produced by this expression system, in addition to those naturally produced by Xf CoDiRO, are underway. Concurrently, a TMV-based vector has been engineered to harbour the same rpfF gene and induce its transient expression in planta. Biologically active transcripts of the vector have been inoculated to Nicotiana tabacum and N. ben- thamiana plants, to establish a model system on herbaceous hosts. RpfF expression was successfully proved by Western blot analysis, whereas movement and systemic colonisation of plant tissues were evaluated by RT-PCR assays. The same viral vector harbouring GFP in replacement of rpfF is used as a control. Following inoculation with Xf CoDiRO bacterial cells the system is now being tested to monitor the persistence of DSF expression and its efficacy to lower disease susceptibility or movement of bacterial cells behind the point of inoculation.