Metabolomic investigation of food matrices by ¹H NMR spectroscopy

The present Ph.D. work shows some applications on the NMR-based metabolomic approach in food science. The investigated food matrices are largely different, from a manufactured product that undergoes only physical treatments (bottarga), to a manufactured product where biochemical transformations take place (Fiore Sardo cheese), and, finally, a raw food (Argentina sphyraena). All of these food matrices were not chosen by chance, but they represent an important piece of economy of the island of Sardinia, or might be further valorized, gaining more importance in the near future. Indeed, bottarga and Fiore Sardo are typical products exported all over the world, while Argentina sphyraena is a fish a low economic interest, finding no appreciation, at the moment, on the market. The results of this PhD study have contributed with new insights and deeper understanding of the potential perspective of the combined NMR/multivariate methods approach in food science, showing the great versatility of NMR spectroscopy and the strong synergetic relation between NMR and chemometrics. NMR revealed its extraordinary potential, when applied to natural samples and products, while chemometric analytical technique proved to be an essential tool to get information on the properties of interest (e.g., geographical origin for bottarga) based on the knowledge of other properties easily obtained (i.e. NMR spectra). The investigation performed on bottarga demonstrated that a NMR-based metabolomics technique can be a powerful tool for the detection of novel biomarkers and establishing quality control parameters for bottarga. The work presented in this study evidenced the effectiveness of metabolite fingerprinting as a tool to distinguish samples according both to the geographical origin of fish and the manufacturing process. The results relative to the Fiore Sardo showed the potential of the combination of NMR spectroscopy and chemometrics as a promising partnership for detailed cheese analysis, providing knowledge that can facilitate better monitoring of the food production chain and create new opportunities for targeted strategies for processing. Such analysis may be performed in any stage of the cheese manufacturing, allowing for thorough evaluation of every step in the process. Finally, the preliminary results relative to the metabolomic investigation of Argentina sphyraena should certainly serve as a basis for implement a research tool able to provide deeper insights on the biology of this fish species with all advantages offered by the metabolomics approach

Self-Assembling Supramolecular Hybrid Hydrogel Beads

With the goal of imposing shape and structure on supramolecular gels, we combine a low molecular weight gelator (LMWG) with the polymer gelator (PG) calcium alginate in a hybrid hydrogel. By imposing thermal and temporal control of the orthogonal gelation methods, the system either forms an extended inter-penetrating network or core-shell structured gel beads – a rare example of a supramolecular gel formulated inside discrete gel spheres. The self-assembled LMWG retains its unique properties within the beads, such as remediating Pd(II) and reducing it in situ to yield catalytically-active Pd(0) nanoparticles. A single PdNP-loaded gel bead can catalyse the Suzuki-Miyaura reaction, constituting a simple and easy-to-use reaction dosing form. These unique shaped and structured LMWG-filled gel beads are a versatile platform technology, with great potential in a range of applications

Fatty Acid Ratios as Parameters to Discriminate Between Normal and Tumoral Cells and Compare Drug Treatments in Cancer Cells

The fatty acid (FA) composition of cell membranes represents a metabolic biomarker. However, the FA profile reproducibility in cell cultures remains a significant challenge. In this study, cell FA ratios are validated as metabolic markers alternative to cell FA. To this goal, cell samples belonging to cancer HeLa cells and normal 3T3 fibroblasts, from various experimental sets, are analyzed by a high-performance liquid chromatography system coupled with a photodiode array detector and evaporative light scattering detector (HPLC-DAD/ELSD), and the ratios among the main FA are calculated. Principal component analysis (PCA) separately performed on FA and FA ratio data indicates similar clustering of cell samples concerning the cell type. Moreover, similar scores values t[1] and t[2] and graphical distances are calculated in the PCA plots separately performed on FA and FA ratios measured in cancer HeLa cells subjected to various antitumoral compounds. Last, PCA applied to selected FA ratios measured in various cell lines, obtained in similar experimental conditions, allows to discriminate between normal and tumoral cells. The results substantiate FA ratios as a cell-specific fingerprint, characterized by reproducibility across intra-laboratory conditions, useful for cell characterization, discrimination between normal and tumoral cells, and the comparison of different drug treatments. Practical Applications: The reproducibility of the fatty acid (FA) profile in cell cultures remains a significant challenge. Results obtained from this study improve knowledge about the role of the FA ratio profile as a cell-specific fingerprint characterized by reproducibility across intra-laboratory conditions. The characterization of the specific FA ratio profile of a cell culture, under standardized experimental conditions, can facilitate the comparative evaluation of cell data sets for nutritional, metabolic, and pharmacological studies, overcoming differences in cell culture conditions and FA extraction/analytical procedures

Self-Propelling Hybrid Gels Incorporating an Active Self-Assembled Low-Molecular-Weight Gelator

Hybrid gel beads based on combining a low-molecular-weight gelator (LMWG) with a polymer gelator (PG) demonstrate enhanced ability to self-propel in water, with the LMWG playing an active role. Hybrid gel beads were loaded with ethanol and shown to move in water via ‘Marangoni effect’ surface tension changes caused by the expulsion of ethanol – smaller beads move further and faster than larger beads. Flat shapes of the hybrid gel were cut using a ‘stamp’ – circles moved the furthest while stars showed more rotational movement on their own axis. Comparing hybrid LMWG/PG gel beads with PG-only beads demonstrated that the LMWG speeds up the beads, enhancing the rate of self-propulsion. Self-assembly of the LMWG into a ‘solid-like’ network prevents its leaching from the gel. The LMWG also retains its own unique function – specifically, remediating methylene blue pollutant dye from basic water as a result of non-covalent interactions. The mobile hybrid beads accumulate this dye more effectively than PG-only beads. Self-propelling gel beads have potential applications in removal/delivery of active agents in environmental or biological settings. The ability of self-assembling LMWGs to enhance mobility and control removal/delivery, suggests that adding them into self-propelling systems can add significant value

Investigation into Cryptosporidium and Giardia in bivalve mollusks farmed in Sardinia region and destined for human consumption

Cryptosporidium and Giardia are protozoan parasites transmitted by fecal-oral ingestion of (oo)cysts, and are responsible for enteritis in several animal species and humans worldwide. These (oo)cysts can survive for over a year in aquatic environments and can accumulate in bivalve mollusks, which filter large volumes of water. The aim of this study is to evaluate the natural occurrence of Cryptosporidium and Giardia contamination in different specimens of edible bivalves mollusks from farming sites of the western and north-eastern coasts of Sardinia. From April 2011 to February 2012, 1095 specimens of Mytilus galloprovincialis and 240 of Crassostrea gigas were sampled from Olbia and Oristano gulf and San Teodoro pond. Hepatopancreas and gills, including the labial palp, were examined for oocysts and cysts after pooling and homogenisation using different techniques: i) staining for light and fluorescence microscopy; ii) direct immunofluorescence (IF) Merifluor® test Cryptosporidium/ Giardia (Meridian Bioscience Inc., Cincinnati, OH, USA); and iii) molecular procedures. However, in the context under study, all mollusks examined with the three main diagnostic techniques were negative for both parasites pointing out the hypothetically low zoonotic risk related to Cryptosporidium and Giardia in bivalves, especially Mytilus galloprovincialis and Crassostrea gigas

Experiences, Emotions, and Health Consequences among COVID-19 Survivors after Intensive Care Unit Hospitalization

Literature suggested that COVID-19 patients experienced hospitalization as a physically and psychologically stressful event, with the risk to develop post-traumatic stress symptoms. The study aimed to understand psychological experiences of COVID-19 survivors with severe complications during and after ICU hospitalization, and any relevant health consequences. From October 2020 to January 2021, a qualitative study was conducted in Italy via semi-structured interviews by phone or video call addressed to COVID-19 survivors, randomly enrolled among people who released their stories publicly on newspapers, television, or social media. Fifteen individuals (three women and twelve men with average age of 56.4 years) were interviewed. Four main themes emerged: (i) emotion of fear; (ii) isolation and loneliness; (iii) unawareness about the gravity of the situation as a protective factor; (iv) "Long COVID" as consequences of the disease on physical and psychological health. During hospitalization, 66.7% of participants had mild or moderate values of anxiety and depression. After discharge, 86.7% moved to normal values. The results suggest that long-COVID is an important problem to manage to improve patients' quality of life. It is essential to guarantee a holistic take in charge starting before the discharge and continuing care after discharge in the community where they live

Spatial and Temporal Diffusion-Control of Dynamic Multi-Domain Self-Assembled Gels

The dynamic assembly of a pH-responsive low-molecular-weight gelator (LMWG) within the pre-formed matrix of a second LMWG has been achieved via diffusion of an acid from a reservoir cut into the gel. Self-assembly of the acid-triggered LMWG as it converts from micellar aggregates at basic pH into gel nanofibers at lower pH values can be both spatially and temporally controlled. The pH-responsive LMWG has an impact on the stiffness of the pre-formed gel in the domains in which it assembles. When low acid concentrations are used, LMWG assembly is transient – after the initial proton diffusion phase, the pH rises and disassembly occurs as the system equilibrates. Re-application of additional acid as ‘fuel’ can then re-assemble the LMWG network. Using glucono-delta-lactone (which slowly hydrolyses to gluconic acid) instead of HCl gives slower, more spatially-restricted assembly, and creates longer-lasting pH gradients within the gel. The presence of an agarose polymer gel network improves the mechanical strength of the gels and appears to slightly enhance the rate of proton diffusion. More sophisticated reservoir shapes can be cut into these more mechanically robust gels, enabling the creation of diffusion waves with different geometries, and hence different patterns of LMWG activation. Multiple reservoirs can be used to create overlapping proton diffusion waves, hence achieving differentiated pH patterns in the gel. Using acid diffusion in this way within gels is an intriguing and powerful way of dynamic patterning. The ability to temporally-evolve spatially-resolved patterns using biocompatible weak acids, and the change in rheological performance of the triggered domains, suggest potential future applications of this strategy in tissue engineering

Hybrid Self-Assembled Gel Beads for Tunable pH-Controlled Rosuvastatin Delivery

This article describes the fabrication of new pH-responsive hybrid gel beads based on combining the polymer gelator calcium alginate with two different low molecular weight gelators (LMWGs) based on 1,3:2,4-dibenzylidene-D-sorbitol: pH-responsive DBS-COOH and thermally-responsive DBS-CONHNH2, clearly demonstrating that different classes of LMWG can be fabricated into gel beads using this approach. We also demonstrate that self-assembled multi-component gel beads can be formed using different combinations of these gelators. The different gel bead formulations exhibit different responsiveness – the DBS-COOH network can disassemble within those beads in which it is present on raising the pH. To exemplify preliminary data for a potential application for these hybrid gel beads, we explored aspects of the delivery of the lipid-lowering active pharmaceutical ingredient (API) rosuvastatin. The release profile of this statin from the hybrid gel beads is pH-dependent, with greater release at pH 7.4 than at pH 4.0 – primary control of this process results from the pKa of the API. The extent of pH-mediated API release, is also significantly further modified according to gel bead composition. The DBS-COOH/alginate beads show rapid, highly effective drug release at pH 7.4, while the three-component DBS-COOH/DBS-CONHNH2/alginate system shows controlled slow release of the API under the same conditions. These initial results indicate that such gel beads constitute a promising, versatile and easily tuned platform suitable for further development for controlled drug delivery applications

Combining gellan gum with a functional low-molecular-weight gelator to assemble stiff shaped hybrid hydrogels for stem cell growth

We report hybrid hydrogels that combine gellan gum (GG) polymer gelator (PG) with a low-molecular weight gelator (LMWG) based on 1,3:2,4-dibenzylidene sorbitol (DBS). We fabricate these gels into beads using a heat–cool cycle to set the LMWG gel and then using different calcium sources (CaCl2 and CaCO3) to subsequently crosslink the gellan gum. In the case of CaCO3, glucono-δ-lactone (GdL) is used as a slow acidification agent to slowly solubilise calcium ions and induce GG crosslinking. Alternatively the photoacid generator, diphenyliodonium nitrate (DPIN) can be used with UV irradiation to solubilise CaCO3 and induce GG gelation, in which case, a photomask applied to gels made in trays yields photopatterned gels. Combining the LMWG with gellan gum further enhances the stiffness of GG, and importantly, makes the gels significantly more resistant to shear strain. LMWG/GG hybrid gels are considerably stiffer than equivalent LMWG/alginate gels. The DBS-CONHNH2 LMWG retains its unique ability to reduce precious metal salts to nanoparticles (NPs) within the hybrid gel beads, as demonstrated by the in situ fabrication of AgNPs. The hybrid gel beads support the growth of human mesenchymal stem cells for extended periods of time. We suggest that the favourable rheological properties of these hybrid gels, combined with the ability of the LMWG to form AgNPs in situ, may enable potential future orthopedic applications

Metabolomics and psychological features in fibromyalgia and electromagnetic sensitivity

Fibromyalgia (FM) as Fibromyalgia and Electromagnetic Sensitivity (IEI-EMF) are a chronic and systemic syndrome. The main symptom is represented by strong and widespread pain in the musculoskeletal system. The exact causes that lead to the development of FM and IEI-EMF are still unknown. Interestingly, the proximity to electrical and electromagnetic devices seems to trigger and/or amplify the symptoms. We investigated the blood plasma metabolome in IEI-EMF and healthy subjects using 1H NMR spectroscopy coupled with multivariate statistical analysis. All the individuals were subjected to tests for the evaluation of psychological and physical features. No significant differences between IEI-EMF and controls relative to personality aspects, Locus of Control, and anxiety were found. Multivariate statistical analysis on the metabolites identified by NMR analysis allowed the identification of a distinct metabolic profile between IEI-EMF and healthy subjects. IEI-EMF were characterized by higher levels of glycine and pyroglutamate, and lower levels of 2-hydroxyisocaproate, choline, glutamine, and isoleucine compared to healthy subjects. These metabolites are involved in several metabolic pathways mainly related to oxidative stress defense, pain mechanisms, and muscle metabolism. The results here obtained highlight possible physiopathological mechanisms in IEI-EMF patients to be better defined