Restoration of a XVII century’s predella reliquary: From physico-chemical characterization to the conservation process

We report on the restoration of a XVII century’s predella reliquary, which is a part of a larger setup that includes a wall reliquary and a wooden crucified Christ, both belonging to the church of “Madre Maria SS. Assunta”, in Polizzi Generosa, Sicily, Italy. The historical/artistic and paleographic research was flanked successfully by the scientific objective characterization of the materials. The scientific approach was relevant in the definition of the steps for the restoration of the artefact. The optical microscopy was used for the identification of the wood species. Electron microscopy and elemental mapping by energy-dispersive X-ray (EDX) was successful in the identification of the layered structure for the gilded surface. The hyperspectral imaging method was successfully employed for an objective chemical mapping of the surface composition. We proved that the scientific approach is necessary for a critical and objective evaluation of the conservation state and it is a necessary step toward awareness of the historical, liturgical, spiritual and artistic value. In the second part of this work, we briefly describe the conservation protocol and the use of a weak nanocomposite glue. In particular, a sustainable approach was considered and therefore mixtures of a biopolymer from natural resources, such as funori from algae, and naturally occurring halloysite nanotubes were considered. Tensile tests provided the best composition for this green nanocomposite glue

Magnetic coiffure: Engineering of human hair surfaces with polyelectrolyte-stabilised magnetite nanoparticles

Here we report a spontaneous electrostatic coating of human hair with aqueous Fe3O4 colloids capable to tailor magnetic properties to hair, orienting and even moving them under the influence of the external magnetic field. Magnetite particles were modified by cationic and anionic polyelectrolytes and then successfully deposited in dense arrays, starting from cuticle gaps and spreading further over a major hair surface. These biocompatible and biodegradable magnetic nanoparticles may serve as carriers for drug loading and delivery for topical pharmaceutical treatments. The deposition process was imaged in real-time using dark-field microscopy. The hair specimens were further studied using a number of characterisation techniques. Under application of an external magnetic field, the nanoparticle magnetic ordering was obtained resulting in the hair alignment and attraction along the field applied. We believe the technology reported here will find a range of applications in topical drug delivery and hair care

Hybrid cellular-inorganic core-shell microparticles: Encapsulation of individual living cells in calcium carbonate microshells

We report the fabrication of hybrid cellular-inorganic core-shell microparticles obtained by encapsulation of individual living yeast cells Saccharomyces cerevisiae in calcium carbonate microshells and demonstrate the viability of the encapsulated cells. Our method is based on the direct precipitation of calcium carbonate on the cell walls of yeast cells. Resulting hybrid microparticles consist of single yeast cells coated with semipermeable inorganic microshells, which resemble the original ellipsoid shapes of yeast cells, exhibit negative zeta-potential, and have micrometer-thick calcium carbonate walls. The combination of the functional properties of living cells and calcium carbonate microshells promises a wide area of applications of these hybrid core-shell microparticles in the development of novel materials. © 2009 American Chemical Society

Toxicological Evaluation of Clay Nanomaterials and Polymer-Clay Nanocomposites

© The Royal Society of Chemistry 2017.Clay nanoparticles are widely used as additives for the fabrication of polymer nanocomposites in industry. The nanoclay dopants effectively attenuate mechanical and functional properties of nanocomposites thus expanding their practical applications. This implies an increased risk of human exposure to nanoclays and\or nanoclay-doped polymer composites. Consequently, the evaluation of the toxicity of nanoclays and nanoclay-doped polymer composites is deemed to be of crucial importance, since the expanding use of nanoclays increases the risk of human exposure. Recent studies report the evaluation of toxicity of various nanoclays employing both in vitro and in vivo models, based on microorganisms, cell cultures, invertebrates and mammals. In this chapter, we overview the toxicity evaluation and biocompatibility studies of clay nanoparticles and nanoclay-doped nanocomposite polymer materials

Microworms swallow the nanobait: The use of nanocoated microbial cells for the direct delivery of nanoparticles into Caenorhabditis elegans

The application of in vivo models in assessing the toxicity of nanomaterials is currently regarded as a promising way to investigate the effects of nanomaterials on living organisms. In this paper we introduce a novel method to deliver nanomaterials into Caenorhabditis elegans nematodes. Our approach is based on using nanoparticle-coated microbial cells as "nanobait", which are ingested by nematodes as a sole food source. We found that nematodes feed on the nanocoated bacteria (Escherichia coli) and microalgae (Chlorella pyrenoidosa) ingesting them via pharyngeal pumping, which results in localization of nanoparticles inside the digestive tract of the worms. Nanoparticles were detected exclusively inside the intestine, indicating the efficient delivery based on microbial cells. Delivery of iron oxide nanoparticles results in magnetic labelling of living nematodes, rendering them magnetically-responsive. The use of cell-mediated delivery of nanoparticles can be applied to investigate the toxicity of polymer-coated magnetic nanoparticles and citrate-capped silver nanoparticles in Caenorhabditis elegans in vivo. © 2013 The Royal Society of Chemistry

"face-lifting" and "make-up" for microorganisms: Layer-by-layer polyelectrolyte nanocoating

Figure Persented: Layer-by-layer encapsulation of living biological cells and other microorganisms via sequential adsorption of oppositely charged functional nanoscale components is a promising instrument for engineering cells with enhanced properties and artificial microorganisms. Such nanoarchitectural shells assembled in mild aqueous conditions provide cells with additional abilities, widening their functionality and applications in artificial spore formation, whole-cell biosensors, and fabrication of three-dimensional multicellular clusters. © 2012 American Chemical Society

Fabrication of Magnetically Responsive Agarose Microbeads Doped with Live Microbial Cells

© 2016, Springer Science+Business Media New York.Here, we report a scalable and rapid method to fabricate magnetically responsive agarose microgels doped with microbial cells. Low-temperature melting agarose and food-grade sunflower oil were used to fabricate microbeads during emulsification and gel setting. Microscopic algae and fungi cells were doped into ∼100-μm-sized beads as single culture or mixed. Magnetic nanoparticles were deposited either on cell walls or on bead walls. We found that the cells encapsulated in magnetically responsive microbeads were viable and able for germination

Naturally derived nano- and micro-drug delivery vehicles: halloysite, vaterite and nanocellulose

Recent advances in drug delivery and controlled release had a great impact on bioscience, medicine and tissue engineering. Consequently, a variety of advanced drug delivery vehicles either have already reached the market or are approaching the phase of commercial production. Progressive growth of the drug delivery market has led to the necessity to earnestly concern about economically viable, up-scalable and sustainable technologies for a large-scale production of drug delivery carriers. We have identified three attractive natural sources of drug carriers: aluminosilicate clays, minerals of calcium carbonate, and cellulose. Three classes of drug delivery carriers derived from these natural materials are halloysite nanotubes, vaterite crystals and nanocellulose. These carriers can be produced using “green” technologies from some of the most abundant sources on the Earth and have extremely high potential to meet all criteria applied for the manufacture of modern delivery carriers. We provide an up-to-date snapshot of these drug delivery vehicles towards their use for bioapplications, in particular for drug delivery and tissue engineering. The following research topics are addressed: (i) the availability, sources and methodologies used for production of these drug delivery vehicles, (ii) the drug loading and release mechanisms of these delivery vehicles, (iii) in vitro, in vivo, and clinical studies on these vehicles, and (iv) employment of these vehicles for tissue engineering. Finally, the prospects for vehicles’ further development and industrialisation are critically assessed, highlighting most attractive future research directions such as the design of third generation active biomaterials

Halloysite clay nanotube composites with sustained release of chemicals

© 2015, Springer Science+Business Media Dordrecht. Halloysite is a naturally occurring nanometer scale tube that is capable of both enhancing the physical properties of a material and functionalizing the material. The addition of halloysite into polymeric materials increases the composite physical strength because of the shape and stability of these 50-nm diameter and ca. 1,500 nm length tubes. Whereas the unique chemical and physical characteristics of halloysite allow for loading drugs, biomacromolecules, anti-corrosion agents, flame-retardant agents, and metal nanoparticles followed by their controlled release. Therefore, by loading a chemical of interest inside of the tubes and then mixing the modified halloysite with various materials one will not only be able to make stronger materials but make them smarter and provide sustained functionality that would otherwise not be possible

Magnetically responsive calcium carbonate microcrystals

Here we report the fabrication of magnetically responsive calcium carbonate microcrystals produced by coprecipitation of calcium carbonate in the presence of citrate-stabilized iron oxide nanoparticles. We demonstrate that the calcite microcrystals obtained possess superparamagnetic properties due to incorporated magnetite nanoparticles and can be manipulated by an external magnetic field. The microcrystals doped with magnetic nanoparticles were utilized as templates for the fabrication of hollow polyelectrolyte microcapsules, which retain the magnetic properties of the sacrificial cores and might be spatially manipulated using a permanent magnet, thus providing the magnetic-field-facilitated delivery and separation of materials templated on magnetically responsive calcite microcrystals. © 2009 American Chemical Society