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

Nematode epicuticle nanoscale morphology: insights from atomic force microscopy

Here we report on imaging and nanomechanical characterisation of microscopic nematodes epicuticle using atomic force microscopy.This study was supported by Russian Science Foundation grant No 14-14-00924 and performed according to the Russian Government Program of Competitive Growth of Kazan Federal University

Nanohydrogel Formation within the Halloysite Lumen for Triggered and Sustained Release

© 2018 American Chemical Society. An easy strategy to obtain nanohydrogels within the halloysite nanotube (HNTs) lumen was investigated. Inorganic reverse micelles based on HNTs and hexadecyltrimethylammonium bromides were dispersed in chloroform, and the hydrophilic cavity was used as a nanoreactor to confine the gel formation based on alginate cross-linked by calcium ions. Spectroscopy and electron microscopy experiments proved the confinement of the polymer into the HNT lumen and the formation of calcium-mediated networks. Biological tests proved the biocompatibility of the hybrid hydrogel. The nanogel in HNTs was suitable for drug loading and sustained release with the opportunity of triggered burst release by chemical stimuli. Here, we propose a new strategy based on inorganic reverse micelles for nanohydrogel formation, which are suitable for industrial and biological applications as well as for selective and triggered adsorption and/or release

Toxicity of halloysite clay nanotubes in vivo: A Caenorhabditis elegans study

© The Royal Society of Chemistry 2015. Here we investigated the toxicity of halloysite clay nanotubes in vivo employing a Caenorhabditis elegans nematode as a model organism. Using enhanced dark-field microscopy and physiological tests, we found that halloysite is localised exclusively in the alimentary system and does not induce severe toxic effects on nematodes

Nanoscale imaging and characterization of Caenorhabditis elegans epicuticle using atomic force microscopy

© 2016 Elsevier Inc.Here we introduce PeakForce Tapping non-resonance atomic force microscopy for imaging and nanomechanical mapping of Caenorhabditis elegans nematodes. The animals were imaged both in air and water at nanoscale resolution. Layer-by-layer glass surface modification was employed to secure the worms for imaging in water. Microtopography of head region, annuli, furrows, lateral alae and tail region was visualized. Analysis of nanoscale surface features obtained during AFM imaging of three larval and adult hermaphrodite nematodes in natural environment allowed for numerical evaluation of annuli periodicity, furrows depth and annuli roughness. Nanomechanical mapping of surface deformation, Young modulus and adhesion confirms that the mechanical properties of the nematode cuticle are non-uniform. Overall, PeakForce Tapping AFM is a robust and simple approach applicable for nanoscale three-dimensional imaging and characterization of C. elegans nematodes

Nano-labelled cells - A functional tool in biomedical applications

© 2014 Elsevier Ltd. All right reserved. Nanotechnology offers an unprecedented number of opportunities for biomedical research, utilizing the unusual functionalities of nanosized materials. Here we describe the recent advances in fabrication and utilization of nanoparticle-labelled cells. We present a brief overview of the most promising techniques, namely layer-by-layer polyelectrolyte assembly on cells and intracellular and extracellular labelling with magnetic nanoparticles. Several important practical application of nanofucntionalized cells, including tissue engineering and tumour therapy, are reviewed

Silver nanoparticle-coated "cyborg" microorganisms: Rapid assembly of polymer-stabilised nanoparticles on microbial cells

© The Royal Society of Chemistry. Fabrication of "cyborg" cells (biological cells with surfaces functionalised using a variety of nanomaterials) has become a fascinating area in cell surface engineering. Here we report a simple procedure for fabrication of polycation-stabilised 50 nm silver nanoparticles and application of these nanoparticles for fabrication of viable "cyborg" microbial cells (yeast and bacteria). Cationic polymer-stabilised nanoparticles electrostatically adhere to microbial cells producing an even monolayer on the cell walls, as demonstrated using enhanced dark-field microscopy, atomic force microscopy and microelectrophoresis. Our procedure is exceptionally fast, being completed within 20 min after introduction of cells into nanoparticle aqueous suspensions. Polymer-stabilised silver nanoparticles are highly biocompatible, with viability rates reaching 97%. We utilised "cyborg" cells built using bacteria and silver nanoparticles to deliver nanoparticles into C. elegans microworms. We believe that the technique described here will find numerous applications in cell surface engineering. This journal i

Surface-Enhanced Raman Scattering to Evaluate Nanomaterial Cytotoxicity on Living Cells

© 2016 American Chemical Society.The increasing number of reports about false positive or negative results from conventional cytotoxicity assays of nanomaterials (NMs) suggests that more reliable NM toxicity assessment methods should be developed. Here, we report a novel approach for nanotoxicity evaluation based on surface-enhanced Raman spectroscopy (SERS). Three model NMs were tested on two model cell lines and the results were validated by WST-1 cytotoxicity assay and annexin V-FITC/propidium iodide (PI) staining as apoptosis-necrosis assay. The localization of nanoparticles (NPs) in the cells and the cellular conditions upon NP incubation were visualized by transmission electron microscopy (TEM) and enhanced dark-field (EDF) microscopy. SERS revealed a broader view on the consequences of cell-NM interactions compared to the conventional cytotoxicity assays where only one aspect of toxicity can be measured by one assay type. The results suggest that SERS can significantly contribute to the cytotoxicity evaluation bypassing NM or assay component-related complications with less effort