Search

An inverted pyramidal metasurface was designed, fabricated, and studied at the nanoscale level for the development of a label-free pathogen detection on a chip platform that merges nanotechnology and surface-enhanced Raman scattering (SERS). Based on the integration and synergy of these ingredients, a virus immunoassay was proposed as a relevant proof of concept for very sensitive detection of hepatitis A virus, for the first time to our best knowledge, in a very small volume (2 μL), without complex signal amplification, allowing to detect a minimal virus concentration of 13 pg/mL. The proposed work aims to develop a high-flux and high-accuracy surface-enhanced Raman spectroscopy (SERS) nanobiosensor for the detection of pathogens to provide an effective method for early and easy water monitoring, which can be fast and convenient.

Imidacloprid is the most widely used insecticide in agriculture and its intensive use over the last 30 years has caused a global concern due to its potentially toxic effects on the ecosystem. Considering the recent scientific interest in novel simple methods for imidacloprid analysis, we propose a label-free sensitive and specific localised surface plasmon resonance system for the detection of the insecticide based on 2D nanostructured metasurfaces with highly performing plasmonic properties. The specificity of the sensor proposed was achieved by covalent bio-functionalization of the metasurface using a smart and easy one-step procedure mediated by carbon disulphide. The biosensor produced was tested using a set of imidacloprid standard solutions showing a competitive limit of detection, lower than 1 ng mL

Biocompatible and bio-based materials are an appealing resource for the pharmaceutical industry. Poly(glycerol-adipate) (PGA) is a biocompatible and biodegradable polymer that can be used to produce self-assembled nanoparticles (NPs) able to encapsulate active ingredients, with encouraging perspectives for drug delivery purposes. Starch is a versatile, inexpensive, and abundant polysaccharide that can be effectively applied as a bio-scaffold for other molecules in order to enrich it with new appealing properties. In this work, the combination of PGA NPs and starch films proved to be a suitable biopolymeric matrix carrier for the controlled release preparation of hydrophobic drugs. Dynamic Light Scattering (DLS) was used to determine the size of drug-loaded PGA NPs, while the improvement of the apparent drug water solubility was assessed by UV-vis spectroscopy. In vitro biological assays were performed against cancer cell lines and bacteria strains to confirm that drug-loaded PGA NPs maintained the effective activity of the therapeutic agents. Dye-conjugated PGA was then exploited to track the NP release profile during the starch/PGA nanocomposite film digestion, which was assessed using digestion models mimicking physiological conditions. The collected data provide a clear indication of the suitability of our biodegradable carrier system for oral drug delivery.

There is significant potential for industrial use of renewables for a wide range of materials demanded by society. Plants, trees and algae are increasingly attracting attention as sustainable sources for functionalised and polymerizable building blocks. In particular, the outer bark of the birch tree (Betula pendula) is a side stream of the forestry industry with so far very little utilisation besides energy recovery. It is composed of a macromolecular network, suberin, that could provide a renewable, low cost and competitive resource. Within raw suberin is the potentially very useful multifunctional extract cis-9,10-epoxy-18-hydroxyoctadecanoic acid (CHA). Our drive has been to develop a green and sustainable synthetic strategy to CHA-based polyesters, by exploiting supercritical carbon dioxide (scCO2) as a reaction medium and leveraging the regio- and chemo-selective properties of the biocatalyst Novozym 435 (Lipase B). Low temperature (35–55 °C) polycondensation in scCO2 shows significant advantages compared to traditional polymerisation methods leading to reasonably high molecular weight polyesters. The mild synthetic conditions also preserve the valuable epoxy groups of the CHA which we show can be exploited by post-polymerisation functionalisation to create sustainable resins for bio-renewable coatings.

Sphingolipids are both structural and bioactive compounds. In particular ceramide and sphingosine 1-phosphate regulate cell fate, inflammation, and excitability. 1-alpha,25-dihydroxyvitamin D3 (1,25(OH)2D3), is known to play an important physiological role on growth and differentiation in a variety of cell types, including neural cells, through genomic actions, mediated by its specific receptor, and non-genomic actions resulting in the activation of specific signalling pathways. 1,25(OH)2D3 and sphingolipids, in particular sphingosine-1-phosphate, share many common effectors, including calcium regulation, growth factors and inflammatory cytokines, but whether they could act synergistically is still unknown. Alterations in the signalling and content of sphingolipids and 1,25(OH)2D3 have been found in neurodegenerative diseases and fingolimod, a structural analogue of sphingosine, has been approved for the treatment of multiple sclerosis. This review, after a brief description of the role of sphingolipids and 1,25(OH)2D3, will focus on the potential crosstalk of sphingolipids and 1,25(OH)2D3 in neural cells.

The widespread diffusion of low-cost but high-performance hardware is enhancing the realization of scientific equipment with features at the research laboratory level. In this paper, we demonstrate hardware implementation of a surface plasmon resonance compact device with high accuracy and measurement times appropriate for many applications. Image acquisition is realized by a Raspberry Pi single board computer with a camera module, and a Python code is used to process data. A flexible optical setup can work in two different configurations, namely, the inspection mode and angle resolved measurement mode. The inspection mode is used to precisely locate the light-emitting diode interrogation beam on the sample, avoiding uneven or faulty regions. The measurement mode allows us to monitor in real time the position of the minimum reflectivity with subpixel resolution. Performance tests show a resolution in the bulk refractive index of 4.9 × 10-6 refractive index units for 10 s acquisition time.

Skeletal muscle (SkM) atrophy is caused by several and heterogeneous conditions, such as cancer, neuromuscular disorders and aging. In most types of SkM atrophy overall rates of protein synthesis are suppressed, protein degradation is consistently elevated and atrogenes, such as the ubiquitin ligase Atrogin-1/MAFbx, are up-regulated. The molecular regulators of SkM waste are multiple and only in part known. Sphingolipids represent a class of bioactive molecules capable of modulating the destiny of many cell types, including SkM cells. In particular, we and others have shown that sphingosine 1phosphate (S1P), formed by sphingosine kinase (SphK), is able to act as trophic and morphogenic factor in myoblasts. Here, we report the first evidence that the atrophic phenotype observed in both muscle obtained from mice bearing the C26 adenocarcinoma and C2C12 myotubes treated with dexamethasone was characterized by reduced levels of active phospho-SphK1. The importance of SphK1 activity is also confirmed by the specific pharmacological inhibition of SphK1 able to increase Atrogin-1/MAFbx expression and reduce myotube size and myonuclei number. Furthermore, we found that SkM atrophy was accomplished by significant increase of S1P transporter Spns2 and in changes in the pattern of S1P receptor (S1PRs) subtype expression paralleled by increased Atrogin-1/MAFbx expression, suggesting a role for the released S1P and of specific S1PR-mediated signaling pathways in the control of the ubiquitin ligase. Altogether, these findings provide the first evidence that SphK1/released S1P/S1PR axis acts as a molecular regulator of SkM atrophy, thereby representing a new possible target for therapy in many patho-physiological conditions.

The human hepcidin-25 hormone has a key role in iron regulation in blood. The clinical relevance of this hepatic ~2.8 kDa cysteine-rich peptide is rapidly increasing, since altered levels can be associated with inflammatory events and iron dysfunctions, such as hereditary hemochromatosis and iron overload. Moreover, hepcidin has also attracted the anti-doping field for its possible role as indirect marker of erythropoietin blood doping. Methods currently reported are based on immunoassays (ELISA and RIA), or various types of mass spectroscopy (MS)-based protocols, semi-quantitative or quantitative. Despite the great effort in optimizing robust and simple assays measuring hepcidin in real matrices, at present this challenge remains still an open issue. To explore the possibility to face hepcidin detection through the development of affinity-based biosensors, we set up a comparative study by surface plasmon resonance (SPR) technology. An immuno-based, on anti-hepcidin-25 IgG, and a biomimetic-based, on a synthetic peptide corresponding to the hepcidin-binding site on ferroportin (HBD), biosensors were developed. Here we report behaviors and analytical performances of the two systems, discussing limits and potentialities.

The human Hepcidin-25 is a cysteine-rich proteinic hormone able to play a key role in systemic iron homeostasis. Indeed it can be associated with inflammatory events and iron dysfunctions but it may be even used as a new bio-marker to estimate indirectly erythropoietin blood doping. Affinity-based biosensors (ABBs) could be applied to hepcidin detection. In this study we adopted optical sensor system for label-free detection, based on Surface Plasmon Resonance (SPR), using as bioreceptor an anti human hepcidin-25 IgG. Limitations, advantages and potentials of this system are briefly discussed in light of behaviours and analytical performances detected.