Colorimetric and Fluorescent Sensing of Copper Ions in Water through o-Phenylenediamine-Derived Carbon Dots

Funding Information: This work was supported by Regione Lazio through Progetto di Ricerca POR FESR LAZIO 2014–2020 Id: A0375-2020-36403 according to G09493 del 14 July 2021. M.A. has been supported by MIUR—Ministero dell’Istruzione Ministero dell’Università e della Ricerca (Ministry of Education, University and Research) under the national project FSE/FESR–PON Ricerca e Innovazione 2014–2020 (N° AIM1887574, CUP: E18H19000350007). This research was also supported by Fundação para a Ciência e Tecnologia, FCT/MCTES, through the Associate Laboratory for Green Chemistry—LAQV (grants UIDB/50006/2020 and UIDP/50006/2020). Publisher Copyright: © 2023 by the authors.Fluorescent nitrogen and sulfur co-doped carbon dots (NSCDs) were synthesized using a simple one-step hydrothermal method starting from o-phenylenediamine (OPD) and ammonium sulfide. The prepared NSCDs presented a selective dual optical response to Cu(II) in water through the arising of an absorption band at 660 nm and simultaneous fluorescence enhancement at 564 nm. The first effect was attributed to formation of cuprammonium complexes through coordination with amino functional groups of NSCDs. Alternatively, fluorescence enhancement can be explained by the oxidation of residual OPD bound to NSCDs. Both absorbance and fluorescence showed a linear increase with an increase of Cu(II) concentration in the range 1–100 µM, with the lowest detection limit of 100 nM and 1 µM, respectively. NSCDs were successfully incorporated in a hydrogel agarose matrix for easier handling and application to sensing. The formation of cuprammonium complexes was strongly hampered in an agarose matrix while oxidation of OPD was still effective. As a result, color variations could be perceived both under white light and UV light for concentrations as low as 10 µM. Since these color changes were similarly perceived in tap and lake water samples, the present method could be a promising candidate for simple, cost-effective visual monitoring of copper onsite.publishersversionpublishe

Nanocomposite anion exchange membranes with a conductive semi-interpenetrating silica network

Nanocomposite anion exchange membranes were synthesized based on poly(sulfone trimethylammonium) chloride. A hybrid semi-interpenetrating silica network containing a large amount of quaternary ammonium groups was prepared by two sol–gel routes, in situ with a single precursor, N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride (TMSP), or ex situ mixing two precursors, TMSP and 3-(2-aminoethylamino)propyldimethoxy-methylsilane (AEAPS). The properties of these hybrid composites and their degradation after immersion in 1 M KOH at 60 °C were studied. The degradation is reduced in the composite materials with a lower decrease in the ion exchange capacity. FTIR spectra showed that a main degradation mechanism with a single precursor TMSP is the dissolution of the hybrid silica network in KOH, whereas it is stable with the mixture of TMSP/AEASP. This conclusion is in agreement with the thermogravimetric analysis. The mechanical properties show a better ductility with a single precursor and higher stiffness and strength, but less ductility, by the ex situ route. The activation energy was between 0.25 and 0.14 eV for Cl and OH ion conduction, respectively, consistent with the migration mechanism

Chiral selectivity of porphyrin-ZnO nanoparticle conjugates

Recognition of enantiomers is one of the most arduous challenges in chemical sensor development. Although several chiral systems exist, their effective exploitation as the sensitive layer in chemical sensors is hampered by several practical implications that hinder stereoselective recognition in solid state. In this paper, we report a new methodology to efficiently prepare chiral solid films, by using a hybrid material approach where chiral porphyrin derivatives are grafted onto zinc oxide nanoparticles. Circular dichroism (CD) evidences that the solid-state film of the material retains supramolecular chirality due to porphyrin interactions, besides an additional CD feature in correspondence of the absorbance of ZnO (375 nm), suggesting the induction of chirality in the underlying zinc oxide nanoparticles. The capability of hybrid material to detect and recognize vapors of enantiomer pairs was evaluated by fabricating gas sensors based on quartz microbalances. Chiral films of porphyrin on its own were used for comparison. The sensor based on functionalized nanostructures presented a remarkable stereoselectivity in the recognition of limonene enantiomers, whose ability to intercalate in the porphyrin layers makes this terpene an optimal chiral probe. The chiroptical and stereoselective properties of the hybrid material confirm that the use of porphyrin-capped ZnO nanostructures is a viable route for the formation of chiral selective surfaces. © 2019 American Chemical Society

Effect of oral docosahexaenoic acid (DHA) supplementation on DHA levels and omega-3 index in red blood cell membranes of breast cancer patients

Rationale: Docosahexaenoic acid (DHA) in cell membrane may influence breast cancer (BC) patients' prognosis, affecting tumor cells sensitivity to chemo- and radio-therapy and likely modulating inflammation. The possibility of identifying BC patients presenting with low DHA levels and/or low ability of DHA incorporation into cell membrane might help to treat this condition. Methods: We enrolled BC patients and healthy controls, recording their seafood dietary intake. DHA in form of algal oil was administered for 10 consecutive days (2 g/day). Blood samples were collected at baseline (T0) and after 10 days of supplementation (T1) to assess DHA, omega-3 index, as the sum of DHA + eicosapentaenoic acid (EPA), in red blood cells (RBC) membranes and plasma tumor necrosis factor-alpha and interleukin-6 levels. Pre- and post-treatment fatty acid profiles were obtained by gas-chromatography. Parametric and non-parametric tests were performed, as appropriate, and P-value < 0.05 was considered statistically significant. Results: Forty-three women were studied, divided into 4 groups: 11 patients with BRCA1/2 gene mutation (M group), 12 patients with familiar positive history for BC (F group), 10 patients with sporadic BC (S group), and 10 healthy controls (C group). DHA and omega-3 index increased from T0 to T1 in the 3 groups of BC patients and in controls (P < 0.001). No difference was found in DHA incorporation between each group of BC patients and between patients and controls, except for M group, which incorporated higher DHA levels with respect to controls (\u3b2 = 0.42; P = 0.03). No association was documented between cytokines levels and DHA and omega-3 index at baseline and after DHA supplementation. Independent of the presence of BC, women considered as "good seafood consumers" showed at baseline DHA and omega-3 index higher with respect to "low seafood consumers" (P = 0.04; P = 0.007, respectively). After supplementation, the increase in DHA levels was greater in "low seafood consumers" with respect to "good seafood consumers" (P < 0.0001). Conclusion: DHA supplementation was associated with increased DHA levels and omega-3 index in RBC membranes of BC cancer patients, independent of the type of BC presentation, and in controls. BRCA1/2 mutation, as well as low seafood consuming habits in both BC patients and healthy controls, seem to be associated with greater ability of DHA incorporation. Larger samples of BC patients are necessary to confirm our observation

Nanomaterials for restoration of damaged plaster surfaces: case of studies

nanomaterials are applied in the restoration and conservation of Cultural Heritage because of several analytical advantages could be obtained thanks to their excellent chemical-physical, mechanical and engineered features. A great deal of nano-scale objects, as: nanoparticles, nanogels, nanofoams, nanosponges, nanopolymers are very useful for the cleaning of the art-work surfaces, restoration and conservation of wall paintings, marble stones, plasters, metallic surfaces and glass mosaic tesserae. Also for the deacidification of the ancient damaged paper, containing iron gall inks, and the preservation of parchment and canvas new nano-scale objects are easily synthesized and applied on these art-work surface

Smart Portable Devices Suitable for Cultural Heritage: A Review

This article reviews recent portable sensor technologies to apply in the Cultural Heritage (CH) fields. The review has been prepared in the form of a retrospective description of the sensor&rsquo;s history and technological evolution, having: new nanomaterials for transducers, miniaturized, portable and integrated sensors, the wireless transmission of the analytical signals, ICT_Information Communication Technology and IoT_Internet of Things to apply to the cultural heritage field. In addition, a new trend of movable tattoo sensors devices is discussed, referred to in situ analysis, which is especially important when scientists are in the presence of un-movable and un-tangible Cultural Heritage and Art Work objects. The new proposed portable contact sensors (directly applied to art work objects and surfaces) are non-invasive and non-destructive to the different materials and surfaces of which cultural heritage is composed

Characterization of three biofilm-forming cyanobacteria and their potential in biotechnological applications.

Biofilms are complex-surface attached communities of both phototrophic (mainly cyanobacteria and microalgae) and heterotrophic microorganisms. There is an increasing interest in understanding how these communities operate, thanks not only to their ecological importance but also to their potential for biotechnological applications (Abed et al. 2009). Microalgae and cyanobacteria in fact, offer the possibility to couple sewage post-treatment with intensive production of biomass, suitable for the extraction of valuable compounds: microalgae, and recently cyanobacteria (Bruno et al. 2012) are considered to be promising feedstock for biofuels, being the productivity of these photosynthetic microorganisms in converting carbon dioxide into carbon-rich lipids highly competitive and sustainable respect to agricultural oleaginous crops (Mata et al. 2010). In addition there is an increasing interest in algal and cyanobacterial polysaccharides from food, pharmaceutical and biomedical industrial sectors. The majority of studies on algal mass cultures for wastewater treatment and bio-product purposes is focused on suspended microalgae, mainly grown in open or enclosed systems, where harvesting or removal of biomass can account for up to 30% of total costs (Wiffels and Barbosa 2010). In this study, three biofilm-forming cyanobacteria, isolated from a dystrophic (iper-eutrophic) coastal lagoon of Cabras (Oristano, Sardinia), were isolated and characterized by a polyphasic approach, involving microscopy observations, ecological investigation and gene sequencing. The isolates were grown in batch systems and in a semi-continuous flow incubator, specifically designed for biofilms development. The biomass produced by each isolate was then used to extract, quantify and characterize exopolysaccharides and lipids. Data obtained from the flow-lane incubator system would support a more economical and sustainable use of the benthic microorganisms for biomass production. All strains produced exopolysaccharides with differing ratios of hydrophobic and hydrophilic moieties depending on the species and the polysaccharide fraction (i.e., whether capsular or released). The produced lipids contained fatty acids suitable for a high-quality biodiesel production, showing high proportions of saturated and monounsaturated fatty acids. In this microcosm it was also possible to monitor the nutrient stripping ability of phototrophic benthic biofilms and in particular, their ability of nitrogen and phosphorus removal

Eta1-Allylpalladium complexes with a tridenttate PNP ligand for the assembly of modified screen printed electrodes

Specific Pd-based organometallic complex, in particular the [Pd(η1-CH2–CH=CH2)(P–N–P’)]BF4 was used for the first time, as new material for interesting analytical applications, as the electrochemical detection of guanine, by the assembly of chemically modified Screen Printed Electrodes (SPEs). These electronic devices could be very interesting for the assembly of electrochemical DNA-based biosensor

Tuning the Sensing Properties of Carbon Dots for Colorimetric Detection of Heavy Metals in Water

Carbon dots (CDs) have recently emerged as a new class of fluorescent nanomaterial that can be prepared and modified in order to determine sensitivity to a variety of chemical and biological analytes. This versatility originates from different strategies of synthesis, top–down or bottom–up, that provide the means to perform heteroatom doping and the modulation of surface- and edge-attached functional groups. In particular, their great affinity with heavy-metal ions in water has stimulated a great number of studies on the response to these toxic species. Although most investigations have exploited the fluorescent emission of CDs, much less has been reported on the variations in optical absorbance, which could be more suitable for colorimetric detection in simple and cheap visual-based devices. Previous studies on top–down undoped CDs have demonstrated how slight modifications in synthesis could turn simultaneous sensitivity to As(III), Cd (II), Cu(II), and Pb(II) into a selective response to Cr(VI), due to exposure of the functional groups on the surface and the formation of hydrogen bonds. In this study, we report on the sensitivity of bottom–up nitrogen-and-sulfur co-doped CDs (NS-CDs) prepared using a simple one-pot hydrothermal method. We show how tuning the pH of the sensing solution greatly reduced the interference effects of Fe(III) and enhanced sensitivity to Cu(II) through the emergence of a distinct absorption band at 660 nm. This was attributed to the formation of cuprammonium complexes through N-containing functional groups. The concurrent response to Co(II) in a different spectral region also suggests the possibility of dual-species multiple sensitivity. The NS-CDs were characterized using TEM, STEM-coupled EDX analysis, NMR, and IR spectroscopy. The response to Cu(II) was linear in the concentration range of 1–100 µM with a limit of detection of 100 nM. Interestingly, the present system neither requires any other reagents nor any previous assay treatment