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This study aimed to investigate the influence of genetic variants in neuroplasticity-related genes on antidepressant treatment phenotypes. The BDNF-TrkB signaling pathway, as well as the downstream kinases Akt and ERK and the mTOR pathway, have been implicated in depression and neuroplasticity. However, clinicians still struggle with the unpredictability of antidepressant responses in depressed patients. We genotyped 26 polymorphisms in BDNF, NTRK2, NGFR, CREB1, GSK3B, AKT, MAPK1, MTOR, PTEN, ARC, and SYN1 in 80 patients with major depressive disorder treated according to the Texas Medical Algorithm for 27 months at Hospital Magalhães Lemos, Porto, Portugal. Our results showed that BDNF rs6265, PTEN rs12569998, and SYN1 rs1142636 SNP were associated with treatment-resistant depression (TRD). Additionally, MAPK1 rs6928 and GSK3B rs6438552 gene polymorphisms were associated with relapse. Moreover, we found a link between the rs6928 MAPK1 polymorphism and time to relapse. These findings suggest that the BDNF, PTEN, and SYN1 genes may play a role in the development of TRD, while MAPK1 and GSK3B may be associated with relapse. GO analysis revealed enrichment in synaptic and trans-synaptic transmission pathways and glutamate receptor activity with TRD-associated genes. Genetic variants in these genes could potentially be incorporated into predictive models of antidepressant response.

Algae are an underexploited source of natural bioactive compounds in Western countries, so an increasing interest in the valorization of these marine organisms has emerged in recent years. In this work, the effect of extracting solvent on the extraction yield, phenolic content, antioxidant capacity, and antimicrobial activity of nine brown macroalgae species (Ascophyllum nodosum, Himanthalia elongata, Undaria pinnatifida, Pelvetia canaliculata, Saccharina latissima, Bifurcaria bifurcata, Laminaria ochroleuca, Sargassum muticum, and Fucus spiralis) was assessed. Total phenolic content (TPC) and the antioxidant properties of extracts by different assays: radical scavenging activity (DPPH-RSA) and ferric reducing antioxidant power (FRAP) were performed. The antimicrobial activity of extracts was studied against six different foodborne microorganisms: Staphylococcus aureus, Staphylococcus epidermidis, Bacillus cereus, Escherichia coli, Salmonella enteritidis, and Pseudomonas aeruginosa. The highest extraction yield was achieved in ethanolic extracts. However, the highest TPC and FRAP values were obtained on the ethyl acetate extracts, especially from A. nodosum. Concerning algal species, the highest TPC and FRAP values were found in A. nodosum, while the highest DPPH-RSA values were achieved in the hexane extracts of B. bifurcata. The antimicrobial activity of algal extracts varied according to the solvent and alga selected, suggesting the species- and solvent-dependent behavior of this property, with B. bifurcata extracts showing the highest results for a wide range of bacteria. Our results provide insight on the characterization of widespread brown algae in the coasts of the North-Western region of the Iberian Peninsula, reflecting multiple health-enhancing properties which may lead to their exploitation in food, pharmacological, and cosmetic industries. European Commission | Ref. UP4HEALTH (H2020-BBI-JTI-2019) n. 888003 Programa Iberoamericano de Ciencia y Tecnología | Ref. CYTED— AQUA-CIBUS, P317RT0003 European Commission | Ref. ERA-NET ERA-HDHL (H2020) (n 696295) Fundação para a Ciência e a Tecnologia | Ref. PTDC / OCE-ETA / 30240 / 2017 Fundação para a Ciência e a Tecnologia | Ref. POCI-01-0145-FEDER-030240 Fundação para a Ciência e a Tecnologia | Ref. UIDB / 50016/2020 Ministerio de Ciencia e Innovación | Ref. RYC-2017-22891 Xunta de Galicia | Ref. ED431F 2020/12 Xunta de Galicia | Ref. ED481A- 2019/295

Recently, the value of wood residues has received increasing attention due to the presence of pharmacologically active compounds. In the present study, apple bark was treated with subcritical water (SWE) with the aim of bioactivity determination and chemical analysis by GC–MS applying two different sample preparation protocols and by HPLC. Extracts were screened for their total antioxidant capacity by means of total phenolic (TPC) and flavonoid contents (TFC), ferric reducing antioxidant power (FRAP) and DPPH-radical scavenging activity (DPPH-RSA). Anti-microbial and anti-proliferative activities of the apple bark subcritical water extracts were also examined. Different lignin and cellulose degradation products were identified by GC–MS, as well as naturally present compounds. Identified compounds encompassed organic and fatty acids, alcohols, sugars, phenol, benzaldehyde, cinnamic acid, cinnamaldehyde and azulene derivatives, as well as other organic compounds. Phenolic profiles of apple bark extracts defined by HPLC–PDA analysis revealed that the main contributors were gallic acid (9.4 ± 0.5 mg/g DW) and catechin (8.3 ± 0.4 mg/g DW). The diversity of the extracts composition supports the fact that this medium is able to extract compounds of different polarities, simultaneously acting as catalyst and reactant. The characterized apple bark extracts demonstrated good antioxidant (TPC = 31.47 ± 1.86 mg GAE/g; TFC = 17.40 ± 1.89 mg EE/g; FRAP = 22.45 ± 2.22 mg AAE/g; DPPH-RSA = 22.57 ± 2.24 mg Trolox E/g DW), antimicrobial (MIC = 19.53–156.25 μg/mL) and anti-proliferative activity (IC50 = 19.88–47.44 μg/mL). The findings of this study showed that SWE can be used as an environmentally friendly and safe technique for the valorization of apple tree wood residues, applicable in food and pharmaceutical industries., The authors are grateful to the Serbian Ministry of Education, Science and Technological Development (451-03-68/2020-14/200134), Provincial Secretariat for High Education and Scientific Research AP Vojvodina, Serbia (Project No. 142-451-3240/2020-03), Provincial Secretariat for Science and Technological Development and Portuguese Ministry of Science (FCT/Servia 2015/2016 proc. 441.00 SERVIA). Financial support from the Ministerio de Economía y Competitividad (Spanish Government) through the Grant CTQ2016-77155-R is also gratefully acknowledged. R. Suárez thanks to the Conselleria d’Educació, Cultura i Universitats from the Government of the Balearic Islands for a PhD stipend co-financed by Fondo Social Europeo (FPI/1444/2012). S. Clavijo acknowledges to Torres Quevedo Program of the Ministerio de Economía y Competitividad (MINECO) co-financed by European Funds, for the financial support through the PTQ 15-08038. This work was also supported by UIDB/50006/2020 and UIDP/50006/2020 by the Fundação para a Ciência e a Tecnologia (FCT)/Ministério da Ciência, Tecnologia e Ensino Superior (MCTES) through national funds. Manuela M. Moreira (project CEECIND/02702/2017) is grateful for the financial support financed by national funds through FCT and to REQUIMTE/LAQV. Manuela M. Moreira (SFRH/BPD/97049/2013) and M. F. Barroso (SFRH/BPD/78845/2011) are grateful for the postdoctoral fellowships financed by POPH-QREN—Tipologia 4.1—Formação Avançada, subsidized by Fundo Social Europeu and Ministério da Ciência, Tecnologia e Ensino Superior. The financial support from Fundação para a Ciência e Tecnologia/ Ministério da Ciência, Tecnologia e Ensino Superior (FCT/MEC) through national funds and co-financed by European Regional Development Fund (FEDER), under the Partnership Agreement PT2020 through the project UID/ QUI/50006/2013—POCI/01/0145/FERDER/007265 is also acknowledged. Annick Boeykens wishes to acknowledge Odisee for funding by means of a PWO grant (Flemish Government; Belgium).

n the last few decades, attention on new natural antimicrobial compounds has arisen due to a change in consumer preferences and the increase in the number of resistant microorganisms. Macroalgae play a special role in the pursuit of new active molecules as they have been traditionally consumed and are known for their chemical and nutritional composition and their biological properties, including antimicrobial activity. Among the bioactive molecules of algae, proteins and peptides, polysaccharides, polyphenols, polyunsaturated fatty acids and pigments can be highlighted. However, for the complete obtaining and incorporation of these molecules, it is essential to achieve easy, profitable and sustainable recovery of these compounds. For this purpose, novel liquid–liquid and solid–liquid extraction techniques have been studied, such as supercritical, ultrasound, microwave, enzymatic, high pressure, accelerated solvent and intensity pulsed electric fields extraction techniques. Moreover, different applications have been proposed for these compounds, such as preservatives in the food or cosmetic industries, as antibiotics in the pharmaceutical industry, as antibiofilm, antifouling, coating in active packaging, prebiotics or in nanoparticles. This review presents the main antimicrobial potential of macroalgae, their specific bioactive compounds and novel green extraction technologies to efficiently extract them, with emphasis on the antibacterial and antifungal data and their applications., The research leading to these results received financial support from Programa de Cooperación Interreg V-A España—Portugal (POCTEP) 2014–2020 (projects Ref. 0181_NANOEATERS_01_E and Ref. 0377_IBERPHENOL_6_E); from MICINN supporting the Ramón and Cajal grant for M.A. Prieto (RYC-2017-22891); from Xunta de Galicia and University of Vigo supporting the pre-doctoral grant of P. García-Oliveira (ED481A-2019/295); by EcoChestnut Project (Erasmus + KA202) supporting the work of M. Carpena and from postdoctoral support for P. Gullón working under the project Bio Based Industries Joint Undertaking (JU) under grant agreement No 888003 UP4HEALTH Project (H2020-BBI-JTI-2019). This work also received financial support from REQUIMTE/LAQV, National Funds (FCT, Fundação para a Ciência e Tecnologia) through project UID/QUI/50006/2019 and by FEDER—Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020—Operational Programme for Competitiveness and Internationalisation (POCI), and by Portuguese funds through FCT—Fundação para a Ciência e a Tecnologia in the framework of the project POCI-01-0145-FEDER-030240—PTDC/OCE-ETA/30240/2017.

The search for food resources is a constant in human history. Nowadays, the search for natural and safe food supplies is of foremost importance. Accordingly, there is a renewed interest in eco-friendly and natural products for substitution of synthetic additives. In addition, microbial contamination of food products during their obtaining and distribution processes is still a sanitary issue, and an important target for the food industry is to avoid food contamination and its related foodborne illnesses. These diseases are fundamentally caused by certain microorganisms listed in this review and classified according to their Gram negative or positive character. Algae have proven to possess high nutritional value and a wide variety of biological properties due to their content in active compounds. Among these capabilities, macroalgae are recognized for having antimicrobial properties. Thus, the present paper revises the actual knowledge of microbial contaminants in the food industry and proposes antimicrobial algal compounds against those pathogenic bacteria responsible for food contamination as valuable molecules for its growth inhibition. The capacity of algae extracts to inhibit some major food pathogen growth was assessed. Moreover, the main applications of these compounds in the food industry were discussed while considering their favorable effects in terms of food safety and quality control, The research was funded by Programa de Cooperación Interreg V-A España—Portugal (POCTEP) 2014–2020 (projects ref. 0181_NANOEATERS_01_E and ref. 0377_IBERPHENOL_6_E) that supports the pre-doctoral grant for C. Jimenez-Lopez; by MICINN supporting the Ramón&Cajal grant for M. A. Prieto (RYC-2017-22891); by Xunta de Galicia and University of Vigo supporting the post-doctoral grant for M. Fraga-Corral (ED481B-2019/096); by Axudas Conecta Peme (Xunta de Galicia) supporting the IN852A 2018/58 NeuroFood Project; AlgaMar (www.algamar.com) that supports the pre-doctoral grant for C. Lourenço-Lopes; by EcoChestnut Project (Erasmus+ KA202) for supporting the work of M. Carpena; and by the project Bio Based Industries Joint Undertaking (JU) under grant agreement no 888003 UP4HEALTH Project (H2020-BBI-JTI-2019) for supporting the postdoctoral work of P. Gullón. This work also received financial support from REQUIMTE/LAQV, National Funds (FCT, Fundação para a Ciência e Tecnologia) through project UID/QUI/50006/2019 and by FEDER—Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020—Operational Programme for Competitiveness and Internationalisation (POCI), and by Portuguese funds through FCT—Fundação para a Ciência e a Tecnologia in the framework of the project POCI-01-0145-FEDER-030240—PTDC/OCE-ETA/30240/2017.

This study gives new insights to understand the type of interactions between Ginkgo biloba L. and Scutellaria baicalensis Georgi, two Chinese medicinal plants with well documented neuroprotective effects, on three targets in Alzheimer's disease (AD): acetylcholinesterase (AChE) and butyrylcholnesterase (BuChE) inhibition and hydrogen peroxide scavenging. Individual samples, binary mixtures with different proportions of both plant species, and also a commercial multicomponent combination containing both plants together with unroasted Coffea arabica L. and quercetin-3-O-rutinoside were used to perform this in vitro evaluation. Sample phenolic profiles were also determined by HPLC-DAD, showing the presence of several flavonoid glycosides, phenolic acids and a methylxanthine. In order to investigate the possible synergism/antagonism interaction, data obtained were analyzed by CompuSyn software. The results showed that G. biloba and S. baicalensis alone display better activities than in mixtures, most of the interactions exhibiting different degrees of antagonism. A slight synergism interaction was only observed for the commercial multicomponent mixture tested against H2O2. Further analysis was carried out to understand which compounds could be responsible for the antagonistic interaction. Seventeen single pure compounds present in all extracts were tested against AChE inhibition, most of them displaying weak or no activity. Only caffeine had a remarkable activity. Five different binary and quaternary mixture compositions were design to deepen the interaction between these compounds, revealing mainly phenolic acid-flavonoid, flavonoid-flavonoid and methylxanthine-flavonoid-phenolic acid antagonistic interactions. These results clearly show that, for the targets evaluated, there is no potentiation of the neuroprotective effect by combining S. baicalensis and G. biloba extracts.

In this contribution an electrochemical study is described for the first time of lipid peroxidation and the role of antioxidant on lipid protection using large unilamellar vesicles (LUVs). In order to simulate the cell membrane, LUVs composed of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) were used. A vesicle-modified electrode was constructed by immobilizing DOPC LUVs onto carbon paste electrodes (CPEs). Lipid peroxidation was studied electrochemically by incubating the vesicle-modified electrodes with hydroxyl (HO) radicals generated via the Fenton reaction. Oxidative damage induced by HO was verified by using square wave voltammetry (SWV) and was indirectly measured by the increase of electrochemical peak current to [Fe(CN)6]4- which was used as the electrochemical label. Ascorbic acid (AA) was used as the antioxidant model in order to study its efficacy on free radical scavenging. The decrease of the electrochemical signal confirms the protective key role promoted by AA in the prevention of lipid peroxidation in vesicles. Through microscopy, it was possible to observe morphologic modification on vesicle structures after lipid peroxidation in the presence or absence of AA., This work was financial supported by Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Río Cuarto, and Agencia Nacional de Promoción Científica y Técnica, Marie Curie Actions, International Research Staff Exchange Scheme FP7-PEOPLE-2013-IRSES (612545), and by the European Union (FEDER funds through COMPETE) and National Funds (FCT-Fundação para a Ciência e a Tecnologia) through UID/QUI/50006/2013 and through grants no. PEst-C/EQB/LA0006/2013 and FCOMP-01-0124-FEDER-037285. Fátima Barroso is grateful to FCT by the grant SFRH/BPD/78845/2011, respectively financed by POPH–QREN–Tipologia 4.1–Formação Avançada, subsidized by Fundo Social Europeu and Ministério da Ciência, Tecnologia e Ensino Superior.is gratefully acknowledged. M. A. L. thanks from CONICET for a research post-doctoral fellowship.

Subcritical water extraction (SWE) has become a popular green extraction technique for the isolation of different classes of compounds from natural matrices. Low price, safety and green character of water, good yields of target compounds and reduced energy consumption, make this technique favorable for potential industrial applications. The purpose of this study was to evaluate antioxidant, antimicrobial and cytotoxic activity of four medicinal plants traditionally used in folk medicine of Serbia. Black mulberry (Morus nigra L.), wall germander (Teucrium chamaedrys L.), wild geranium (Geranium macrorrhizum L.) and comfrey (Symphytum officinale L.) were extracted by subcritical water at different temperatures. Antioxidant activity of the extracts was defined by conventional spectrophotometric methods, such as the total phenolic content (TPC), DPPH-radical scavenging activity (DPPH-RSA), ferric reducing antioxidant power (FRAP) and total antioxidant capacity (TAC) assessed by a DNA-based sensor. Additionally, the main phenolic compounds contributing to the antioxidant activity of the produced extracts were also identified and quantified by high performance liquid chromatography with diode array detection (HPLC-DAD). Antimicrobial properties of extracts were evaluated against eight microbial strains. Furthermore, the cytotoxic activity was observed for two human cancer cell lines and a cell line derived from murine fibroblast., The project 6818–Transnational Cooperation, Agreement between Portugal (FCT) and Serbia (MSTD) is acknowledged. This work was also funded by project TR 31014 financially supported by the Serbian Ministry of Education, Science and Technological Development. Financial support from project within the bilateral cooperation between the Republic of Serbia and the Republic of Croatia is gratefully acknowledged. Authors are also grateful for financial support from project NORTE-01-0145-FEDER-000011–311 Qualidade e Segurança Alimentar—uma abordagem (nano) tecnológica. The financial support from FCT/MEC through national funds and co-financed by FEDER, under the Partnership Agreement PT2020 through the project UID/QUI/50006/2013–POCI/01/0145/FEDER/007265, is also acknowledged. M.F. Barroso (SFRH/BPD/78845/2011) and Manuela M. Moreira (SFRH/BPD/97049/2013) are grateful to Fundação para a Ciência e Tecnologia for their postdoctoral fellowships.

This work addresses the development of a disposable electrochemical genosensor for the detection of the toxic dinoflagellate, Alexandrium minutum. Analyzing public databases, a specific 70 bp DNA probe, targeting A. minutum, was selected and designed. The genosensor methodology implied the immobilization of a A. minutum-specific DNA-capture probe onto screen-printed gold electrodes (SPGE). To improve both the selectivity and to avoid strong secondary structures, that could hinder the hybridization efficiency, a sandwich format of the A. minutum gene was designed using a fluorescein isothiocyanate-labelled signaling DNA probe and enzymatic amplification of the electrochemical signal. Using this electrochemical genosensor, a concentration range from 0.12 to 1.0 nM, a LD of 24.78 pM with a RSD, INCT-EN -Instituto Nacional de Ciência e Tecnologia para Excitotoxicidade e Neuroproteção(SFRH/BPD/78845/2011)

A novel and disposable electrochemical biosensor for PCR-free and selective detection of Sola l 7, a non-specific lipid transfer protein (nsLTP) found in tomato seeds associated to severe symptoms of tomato-allergic patients, is reported in this work. The methodology involves the formation of DNA/RNA heterohybrids by sandwich hybridization of a specific fragment of the Sola l 7 allergen coding sequence with appropriate RNA probes designed and described for the first time in this work. Labeling was carried out with commercial antibodies specific to the heteroduplexes and secondary antibodies conjugated with HRP onto the surface of magnetic beads. Amperometric transduction was performed upon magnetic capture of the resulting magnetic bioconjugates on screen-printed electrodes using the system H2O2/HQ. A comparison of the sandwich hybridization format with a direct approach as well as between different labeling strategies was performed. The LOD value achieved was 0.2 pM (5 amol in 25 μL). The biosensor was successfully applied to the selective analysis of the targeted Sola l 7 specific region directly in just 100 ng of non-fragmented denatured genomic DNA extracted from tomato seeds., The financial support of the Spanish Ministerio de Economía y Competitividad Research Projects, CTQ2015-64402-C2-1-R, SAF2017-86483-R and the TRANSNANOAVANSENS Program from the Comunidad de Madrid (Grant P2018/NMT-4349) are gratefully acknowledged. M.F.B. is grateful to FCT grant SFRH/BPD/78845/2011,financed by POPH–QREN–Tipologia4.1–Formação Avançada, subsidized by Fundo Social Europeu and Ministério da Ciência, Tecnologiae Ensino Superior. The author M.A.P.B. is grateful to the authors J.M.R., M.F.B., S.C., J.M.P. for the scientific assistance and suggestions shared throughout the supervision of her Master’s project and Master’s thesis at University of Minho. The author M.A.P.B. also acknowledges the Department of Biology (DB) and the Centre of Molecular and Environmental Biology (CBMA) from University of Minho (UM), Braga,Portugal, by providing all the conditions leading to the Master's thesis in“Biophysics and Bionanosystems”. Financial support of M.A.P.B. forthis work was provided by a fellowship within the programme Erasmus+ scholarship/Portugal, which allowed performing the laboratorial work at the University Complutense of Madrid, Madrid, Spain. The author J.M.R. acknowledges CBMA-UM and DB-UM, Portugal, by the conditions provided. J.M.R. is also grateful to the Green Chemistry Laboratory (LAQV)–Research center Chemistry and Technology Network (REQUIMTE), and the Department of Chemistry and Biochemistry (DCB) from Faculty of Sciences, University of Porto(FCUP), Porto, Portugal, where currently he is researcher. J.M.R. acknowledges the financial support of the strategic programmes UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) and PTDC/SAUNUT/30448/2017 (POCI-01-0145-FEDER-030448) and M.F.B. the financial support of the projects PTDC/QUI-QAN/30735/2017 and UID/QUI/50006/2019, funded by national funds through Fundação para a Ciência e Tecnologia [Foundation for Science and Technology](FCT-I.P.)/Ministério da Ciência, Tecnologia e Ensino Superior [Ministry of Science, Technology and Higher Education] (MCTES), and Fundo Europeu de Desenvolvimento Regional [European RegionalDevelopment Fund] (FEDER), under the scope of the COMPETE2020–Programa Operacional Competitividade e Internacionalização[COMPETE2020–Competitiveness and InternationalizationOperational Program, POCI]. S.B. acknowledges the financial support from MINECO through the“Juan de la Cierva” program.

This work addresses a technological advance applied to the construction of a magnetogenoassay with electrochemical transduction for the maize taxon-specific (HMGA gene) detection using gold-coated magnetic nanoparticles as nanosized platform. Superparamagnetic core-shell Fe

Summary This study aimed to evaluate the effect of microwave-assisted extraction (MAE) parameters on the composition and bioactivity of goji (Lycium barbarum) extracts. Extracts were obtained under a central composite design combination of experimental conditions, and characterised through HPLC-DAD; their bioactive capacity was ascertained for antimicrobial and antioxidant capacity, the later by spectrophotometric [2,2-azinobis (3- ethylbenzothiazoline-6-sulfonic acid) diammonium salt-radical scavenging activity assay – 413–748 mg ascorbic acid equivalents/100 g DW and oxygen radical absorbance capacity – 1901–2292 mg trolox equivalents/100 g DW] and electrochemical (DNA-based sensor – 3571–6602 mg ascorbic acid/100 g DW) methods. The quantitative profile of phenolic compounds was strongly dependent on MAE conditions. Significant correlations were found between the presence of several flavonoids and solvent composition, as well as between phenolic acids with methoxy group and the response to DNA-based sensor. Results may improve targeted extractions for specific compounds, leading to the achievement of extracts richer in antioxidant capacity, as well as in the tailoring of the biosensor response sensitivity to the composition of the extracts under analysis.

In this contribution a strategy is shown to covalently immobilize gold nanoparticles (AuNPs) onto vesicle bilayers with the aim of using this nanomaterial as platform for the future design of immunosensors. A novel methodology for the self-assembly of AuNPs onto large unilamellar vesicle structures is described. The vesicles were formed with 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1-undecanethiol (SH). After, the AuNPs photochemically synthesized in pure glycerol were mixed and anchored onto SH–DOPC vesicles. The data provided by voltammetry, spectrometry and microscopy techniques indicated that the AuNPs were successfully covalently anchored onto the vesicle bilayer and decorated vesicles exhibit a spherical shape with a size of 190 ± 10 nm. The developed procedure is easy, rapid and reproducible to start designing a possible immunosensor by using environmentally friendly procedures.

In this work, we report a new chemiluminescence system using bis-(2,4,6-trichlorophenyl) oxalate (TCPO) with hydrogen peroxide and luminol as fluorophore. The intense chemiluminescence reaction here described was fully investigated and it was determined that this fluorescent system has two strong light emissions at 440 and 490 nm, respectively. This new, user friendly, intense and striking light emission chemiluminescence system can be used as a very usefull tool for the design and construction of fluorescencent chemical sensors., This work received financial support from the European Union (FEDER funds through COMPETE) and National Funds (FCT - Fundação para a Ciência e a Tecnologia) through project UID/QUI/50006/2013.

This work received financial support from the European Union (FEDER funds through COMPETE), National Funds (FCT, Fundação para a Ciência e a Tecnologia) through project UID/QUI/50006/2013. A.P. and M.F.B. are grateful to FCT grants SFRH/BD/97995/2013 and SFRH/BPD/78845/2011, financed by POPH–QREN–Tipologia 4.1–Formação Avançada, subsidized by Fundo Social Europeu and Ministério da Ciência, Tecnologia e Ensino Superior. C.P. thanks FCT for the FCT Investigator contract IF/01080/2015., Development of expeditious analytical methods for the detection of genetically modified organisms (GMOs) is increasingly necessary, not only to verify compliance with labelling, but also to help industry to efficiently control the reception of raw materials. On the basis of this, a disposable electrochemical magnetogenoassay is proposed for simultaneous detection of two Roundup Ready (RR) soybean lines GTS 40-3-2 and MON89788, using gold-coated magnetic nanoparticles (Fe3O4@Au) as nanosupport. To perform this magnetogenoassay, a sandwich-type hybridization assay was used with different enzymatic labelling systems (fluorescein isothiocyanate and digoxigenin) and dual screen-printed carbon electrodes (SPdCEs), which allowed the simultaneous readout of each target. A linear relationship ranging from 0.1 to 2.5 nM and from 0.1 to 1.0 nM was achieved for GTS 40-3-2 and MON89788 events, respectively, and both assays showed a similar detection limit of about 0.1 nM. Furthermore, a good performance in terms of precision and selectivity was achieved. The proposed approach is a step forward for event-specific multiplex detection.

Polymeric ion selective electrodes are highly sensitive to changes in zero current ion flow and this offers a route to signal amplification in label-free potentiometric immunosensors. In this work, a label-free potentiometric immunosensor toward Salmonella typhimurium (ST) assembled in a home-made pipette-tip electrode is described. The signal-output amplification was implemented on a gold nanoparticle polymer inclusion membrane (AuNPs-PIM) which was used as sensing platform and for antibody immobilization. Additionally, a marker ion was used to detect the antibody-antigen binding event at the electrode surface. The immunosensor construction was performed in several steps: i) gold salt ions extraction in PVC membrane; ii) AuNPs formation using Na2EDTA as reduction agent; iii) antibody anti-Salmonella conjugation on AuNPs-PIM in pipette-tip electrodes. The potential shift observed in potentiometric measurements was derived simply from the blocking effect in the ionic flux caused by antigen-antibody conjugation, without no extra steps, mimetizing the ion-channel sensors. A detection limit of 6 cells mL-1 was attained. As proof-of-concept, recovery studies were performed in spiked commercial apple juice samples with success. Due to the simplicity of use, the appealing cost of equipment and sensor production and being able to provide a quick analytical response (less than 1 h for a complete assay, including sample preparation for analysis), this scheme represents a good prototype device for the detection of foodborne pathogens like ST or other immune-responsive bacteria., This work received financial support from the European Union (FEDER funds through COMPETE) and National Funds from Portugal; FCT-Fundação para a Ciência e a Tecnologia through projects UID/QUI/50006/2013 and Norte-01-0145-FEDER-000011-RL1-QUALIFOOD. N.F.D Silva and M.F. Barroso are gratefully to FCT grant SFRH/BD/112414/2015 and SFRH/BPD/78845/2011, financed by POPH–QREN–Tipologia 4.1–Formação Avançada, subsidized by FSE and MCTES.

Reactive nitrogen and oxygen species are produced in cells and play an important role in the oxidative metabolism; when in abnormal concentrations, they are able to induce oxidative damage on biomolecules, namely in DNA. In this paper it is described, an electrochemical DNA-based sensor against NOradical dot radical developed for total antioxidant capacity (TAC) evaluation. The sensor consisted on dA20 (adenine-rich oligonucleotide) physically adsorbed into carbon paste electrode (CPE). When this dA20-CPE was damaged, by immersion in a freshly generated NOradical dot radical, a protective effect onto dA20 was observed in the presence of antioxidants (ascorbic, gallic, caffeic, p-coumaric acids). Electrochemical studies were performed through square wave voltammetry. The construction of the sensor is simple, fast and the results indicated that the DNA-based sensor is suitable, accurate, and can be used to the assessment of TAC in commercial samples of juices.

The purpose of this work was to develop a reliable alternative method for the determination of the dithiocarbamate pesticide mancozeb (MCZ) in formulations. Furthermore, a method for the analysis of MCZ's major degradation product, ethylenethiourea (ETU), was also proposed. Cyclic voltammetry was used to characterize the electrochemical behavior of MCZ and ETU, and square-wave adsorptive stripping voltammetry (SWAdSV) was employed for MCZ quantification in commercial formulations. It was found that both MCZ and ETU are irreversibly reduced (− 0.6 V and − 0.5 V vs Ag/AgCl, respectively) at the surface of a glassy carbon electrode in a mainly diffusion-controlled process, presenting maximum peak current intensities at pH 7.0 (in phosphate buffered saline electrolyte). Several parameters of the SWAdSV technique were optimized and linear relationships between concentration and peak current intensity were established between 10–90 μmol L − 1 and 10–110 μmol L − 1 for MCZ and ETU, respectively. The limits of detection were 7.0 μmol L − 1 for MCZ and 7.8 μmol L − 1 for ETU. The optimized method for MCZ was successfully applied to the quantification of this pesticide in two commercial formulations. The developed procedures provided accurate and precise results and could be interesting alternatives to the established methods for quality control of the studied products, as well as for analysis of MCZ and ETU in environmental samples.

A new environmentally friendly Au nanoparticles (Au NPs) synthesis in glycerol by using ultraviolet irradiation and without extra-added stabilizers is described. The synthesis proposed in this work may impact on the non-polluting production of noble nanoparticles with simple chemicals normally found in standard laboratories. These Au NPs were used to modify a carbon paste electrode (CPE) without having to separate them from the reaction medium. This green electrode was used as an electrochemical sensor for the nitrite detection in water. At the optimum conditions the green sensor presented a linear response in the 2.0×10-7-1.5×10-5M concentration range, a good detection sensitivity (0.268ALmol-1), and a low detection limit of 2.0×10-7M of nitrite. The proposed modified green CPE was used to determine nitrite in tap water samples. Fil: Gobelli, Dino Joaquin. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina Fil: Correa, Nestor Mariano. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina Fil: Barroso, M. Fátima. Instituto Superior de Engenharia do Porto; Portugal Fil: Moyano, Fernando. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina Fil: Molina, Patricia Gabriela. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina

The integration of nanomaterials in the field of (bio)sensors has allowed developing strategies with improved analytical performance. In this work, ultrasmall core-shell Fe3O4@Au magnetic nanoparticles (MNPs) were used as the platform for the immobilization of event-specific Roundup Ready (RR) soybean and taxon-specific DNA sequences. Firstly, monodisperse Fe3O4 MNPs were synthesized by thermal decomposition and subsequently coated with a gold shell through reduction of Au(III) precursor on the surface of the MNPs in the presence of an organic capping agent. This nanosupport exhibited high colloidal stability, average particle size of 10.2 ± 1.3 nm, and spherical shape. The covalent immobilization of ssDNA probe onto the Au shell of the Fe3O4@Au MNPs was achieved through a self-assembled monolayer (SAM) created from mixtures of alkane thiols (6-mercapto-1-hexanol and mercaptohexanoic acid). The influence of the thiols ratio on the electrochemical performance of the resulting electrochemical genoassays was studied, and remarkably, the best analytical performance was achieved for a pure mercaptohexanoic acid SAM. Two quantification assays were designed; one targeting an RR sequence and a second targeting a reference soybean gene, both with a sandwich format for hybridization, signaling probes labelled with fluorescein isothiocyanate (FITC), enzymatic amplification and chronoamperometric detection at screen-printed carbon electrodes (SPCE). The magnetogenoassays exhibited linear ranges from 0.1 to 10.0 nM and from 0.1 to 5.0 nM with similar detection limits of 0.02 nM and 0.05 nM for the event-specific (RR) and the taxon-specific (lectin) targets, respectively. The usefulness of the approach was demonstrated by its application to detect genetically modified organisms (GMOs) in feed and food., This work received financial support from the European Union (FEDER funds through COMPETE), National Funds (FCT, Fundação para a Ciência e a Tecnologia) through project UID/QUI/50006/2013 and Regional Funds (Principado de Asturias government through Project FC15-GRUPIN14-025), and cofinanced by FEDER funds. A.P. and M.F.B. are grateful to FCT grants SFRH/BD/97995/2013 and SFRH/BPD/78845/2011, financed by POPH–QREN–Tipologia 4.1–Formação Avançada, subsidized by Fundo Social Europeu and Ministério da Ciência, Tecnologia e Ensino Superior. C.P. thanks FCT for the FCT Investigator contract IF/01080/2015.

In the present work, antioxidant compounds from Teucrium montanum were extracted by subcritical water. The influence of extraction temperature and pressure on antioxidant activity of extracts has been investigated in terms of extraction yield (EY), total phenolic content (TPC), and DPPH-radical scavenging activity (DPPH-RSA) and ferric reducing antioxidant power (FRAP). Additionally, the compounds responsible for the antioxidant activity were identified and quantified by high performance liquid chromatography (HPLC). The highest EY (42.63%), TPC (174.61 ± 4.09 mg GAE/g DE) and antioxidant activity by DPPH-RSA (176.23 ± 8.76 mg TE/g DE) and FRAP (141.71 ± 5.21 mg AAE/g DE) were seen in extracts obtained at temperature of 160 °C and pressure of 10 bar. HPLC analysis revealed that naringin and gallic acid were the principle antioxidant compounds in subcritical extracts. According to the results, SWE has a great potential in exploitation of natural sources of bioactive compounds and production of pharmacologically-active fractions., The project 6818 – Transnational Cooperation, Agreement between Portugal (FCT) and Serbia (MSTD) is acknowledged. This work was also funded by project TR 31014 financially supported by the Serbian Ministry of Education, Science and Technological Development. Authors are also grateful for financial support from project NORTE-01-0145-FEDER-000011-311 Qualidade e Segurança Alimentar-uma abordagem (nano) tecnológica. The financial support from FCT/MEC through national funds and co-financed by FEDER, under the Partnership Agreement PT2020 through the project UID/QUI/50006/2013-POCI/01/0145/FEDER/007265, is also acknowledged. M.F. Barroso (SFRH/BPD/78845/2011) and Manuela M. Moreira (SFRH/BPD/97049/2013) are grateful to Fundação para a Ciência e Tecnologia for their postdoctoral fellowships.

ince annually a high amount of wastes is produced in vine pruning, the aim of this study was to evaluate the potential of vine shoots from two Portuguese grape varieties (Touriga Nacional - TN and Tinta Roriz - TR) to be used as a natural source of phenolic compounds. To reach this goal, three techniques were explored, namely microwave-assisted extraction (MAE), subcritical water extraction (SWE) and conventional extraction (CE). The phenolic composition of the extracts, antioxidant and biological activities were evaluated by spectrophotometry and chromatography. MAE and SWE produced the highest concentrated extracts. TR vine shoot variety had the highest antioxidant activity and total phenolic (32.1 ± 0.9 mg gallic acid equivalents/g dry sample), as well as flavonoid content (18.7 ± 1.2 mg epicatechin equivalents/g dry sample). For the first time, the biological activity of the vine shoot extracts was tested. Results demonstrated that all of them had antimicrobial potential against different bacteria and yeasts, and the ability of inhibiting -amylase and acetylcholinesterase enzymes, with MAE TR extracts being the most efficient. HPLC analysis enabled the identification of different phenolic compounds, with gallic acid, catechin, myricetin and kaempferol-3-O-rutinoside being the main contributors to the phenolic composition. Portuguese vine shoot wastes could serve as easily accessible source of natural antioxidants for the food or pharmaceutical industries., Manuela M. Moreira (SFRH/BPD/97049/2013) and M. F. Barroso (SFRH/BPD/78845/2011) are grateful for the postdoctoral fellowships financed by POPH-QREN – Tipologia 4.1 – Formação Avançada, subsidized by Fundo Social Europeu and Ministério da Ciência, Tecnologia e Ensino Superior. The authors are also grateful for the financial support from FCT/MEC through national funds and co-financed by FEDER, under the Partnership Agreement PT2020 through the project UID/QUI/50006/2013 - POCI/01/0145/FEDER/007265; the project 6818 - Transnational Cooperation, Agreement between Portugal (FCT) and Serbia (MSTD) is also acknowledged. This work was also supported by the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) funded by national funds through the FCT I.P. and by the ERDF through the COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI). The supply of the vine shoots is acknowledged to Sogrape Vinhos, S.A., info:eu-repo/semantics/publishedVersion

Eruca sativa (rocket salad) has been intensely consumed all over the world, insomuch as, this work was undertaken to evaluate the antioxidant status and the environmental contamination (positive and negative nutritional contribution) of leaves and stems from this vegetable. Antioxidant capacity of rocket salad was assessed by mean of optical methods, such as the total phenolic content (TPC), reducing power assay and DPPH radical scavenging activity. The extent of the environmental contamination was reached through the quantification of thirteen organochlorine pesticides (OCP) by using gas chromatography coupled with electron-capture detector (GC-ECD) and compound confirmations employing gas chromatography tandem mass-spectrometry (GC-MS/MS). The OCP residues were extracted by using Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) methodology.The extent of the environmental contamination was reached through the quantification of thirteen OCP by using gas chromatography coupled with electron-capture detector (GC-ECD) and compound confirmations employing GC-MS/MS. The OCP residues were extracted by using Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) methodology. This demonstrated that leaves presented more antioxidant activity than stems, emphasizing that leaves contained six times more polyphenolic compounds than stems. In what concerns the OCP occurrence, the average recoveries obtained at the three levels tested (40, 60 and 80 µg kg(-1)) ranged from 55% to 149% with a relative standard deviation of 11%, (except hexachrorobenzene). Three vegetables samples were collected from supermarkets and analysed following this study. According to data, only one sample achieved 16.21 of β-hexachlorocyclohexane, confirmed by GC-MS/MS. About OCP quantification, the data indicated that only one sample achieved 16.21 µg kg(-1) of β-hexachlorocyclohexane, confirmed by GC-MS/MS, being the QuEChERS a good choice for the of OCPs extraction. Furthermore, the leaves consumption guaranty higher levels of antioxidants than stems.

WOS: 000444967800042, PubMed: 30236684, The main goal of this research was to determine the relationship among chemical structure, bioactivity and temperature of chamomile during subcritical water extraction in isobaric conditions (45 bar) at seven different temperatures (65-210 degrees C). The influence of temperature on phenolic profiles was defined by UHPLC-HESI-MS/MS. The overall results indicate that the presence of conjugated double bonds, side chains, glucose moiety or ether moiety in molecules influence the efficiency of polyphenols' extraction in subcritical water. In terms of antioxidant activity, the extracts were the most active towards ABTS radicals (IC50 = 7.3-16.8 mu g/mL), whereby temperature of 150 degrees C was optimal. On the other hand, the extracts obtained at 115 degrees C showed highest cytotoxicity. Inhibition of alpha-amylase and alpha-glucosidase was the highest at 65 and 85 degrees C, i.e. 0.51 and 4.13 mmolAE/g, respectively. Activity against tyrosinase was the highest at 210 degrees C (17.92 mgKAE/g). The data showed that different non-phenolic compounds may also participate in bio-activities of the extracts., Serbian Ministry of Education, Science and Technological Development, Serbia [TR31013, 172017]; Programme PT2020 [NORTE-07-0124FEDER-000069, NORTE-01-0145-FEDER-000011-RL1QUALIFOOD]; FCTPortuguese Foundation for Science and Technology [UID/QUI/50006/2013- POCl/01/0145/ FEDER/007265, SFRH/BPD/78845/2011], The present work was carried out within the projects of the Serbian Ministry of Education, Science and Technological Development, Serbia, (Projects No. TR31013 and 172017). The authors are grateful to Dr Dugan Adamovi, Institute of Field and Vegetable Crops, Baeki Petrovac, Serbia, for his support in supplying plant material.REQUIMTE received financial support from Programme PT2020 (NORTE-07-0124FEDER-000069 and NORTE-01-0145-FEDER-000011-RL1QUALIFOOD) and from FCT (UID/QUI/50006/2013- POCl/01/0145/ FEDER/007265). M. Fatima Barroso would like to thank also to FCT for the post-doc fellowship (SFRH/BPD/78845/2011).

Background: Type 1 diabetes mellitus (T1DM) is an autoimmune disease with beta-cell destruction, resulting in insulin deficiency. It is now clear that environmental factors also play a role in disease development. The prevalence of type 1 diabetes in children and young people in Portugal is 0.16% between 0 and 19 years of age. The main cause of death in T1DM is cardiovascular disease, and early endothelial dysfunction is its pathophysiologycal precursor. Hyperglycemia is associated with increased production of free radicals and increased oxidative stress. The aim of this study was to analyze the antioxidant status in a pediatric portuguese diabetic population. Methods: The study was conducted to characterize and compare the antioxidant status in children aged 2 - 10 years old, with type 1 diabetes and healthy children. Plasmatic profile of total phenolic content (TPC), ferric reducing antioxidant power (FRAP), Trolox equivalent antioxidant capacity (TEAC) in children with diabetes and controls, pre-pubescent, and with BMI < 85th centile were evaluated. Results: FRAP values were significantly lower in diabetic children compared with healthy controls (P < 0.001). There was not any statistical significant difference in the TPC and the TEAC determinations. Conclusions: Young Portuguese diabetic children have a lower antioxidant status than healthy children. J Clin Med Res. 2017;9(12):998-1001 doi: https://doi.org/10.14740/jocmr3120w

This work addresses a technological advance applied to the construction of a magnetogenoassay with electrochemical transduction for the maize taxon-specific (HMGA gene) detection using gold-coated magnetic nanoparticles as nanosized platform. Superparamagnetic core-shell Fe3O4@Au nanoparticles (10.4 ± 1.7 nm) were used to assemble the genoassay through the covalent immobilization of HMGA DNA probes onto carboxylated self-assembled monolayers at the nanoparticles surface. A hybridization reaction using sandwich format was selected to prevent inefficient hybridization connected with stable secondary DNA structures using also fluorescein isothiocyanate as DNA signaling tag. The labelling of the hybridization reaction with enzymes allowed the chronoamperometric measurement of the peroxidase activity linked to the nanoplatform located on gold surface. Using this electrochemical magnetogenoassay a linear concentration range from 0.5 to 5 nM and a LOD of 90 pM with a RSD

For the first time, the characterization of antioxidant activity and phenolic profile of apple tree (Malus domestica) bark, core and roots was carried out. Phenolic compounds were extracted from the Belgium apple tree wood residues collected at two seasons, namely summer 2015 and winter 2016, using conventional (CE) and microwave-assisted extraction (MAE) techniques. For each extraction technique, the influence of the most important operational parameters, namely solvent composition, extraction time and temperature, on the total phenolic and flavonoid content, and antioxidant activity by the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (DPPH-RSA) and ferric reducing activity power (FRAP) assays were optimized. The phenolic profile from the obtained extracts was also characterized by high-performance liquid chromatography with photodiode array detection (HPLC-PDA). Optimum conditions were: 20 mL ethanol:water 60:40 v/v, 20 min, 100 °C, sample weight 0.1 g for MAE and 20 mL ethanol:water 50:50 v/v, 2 h, 55 °C, sample weight 0.5 g for CE. Root extracts obtained by MAE (the most efficient technique) presented the highest phenolic (47.7 ± 0.9 mg gallic acid equivalents/g dry weight) and flavonoid (17.1 ± 0.8 mg epicatechin equivalents/g dry weight) content, and antioxidant activity (28.4 ± 2.0 mg trolox equivalents/g dry weight and 36.1 ± 2.7 mg ascorbic acid equivalents/g dry weight for DPPH-RSA and FRAP assays, respectively), followed by bark and core wood extracts. HPLC-PDA analysis revealed that phloridzin was the main contributor to the phenolic composition representing 52%–87% of the total amount of phenolic compounds quantified, while phenolic acids represents less than 10%. This study reveals the potential of apple tree wood residues valorization through the recovery of phenolic compounds for food, pharmaceutical and cosmetic applications.

This study focused on the development of a sensitive enzymatic biosensor for the determination of pirimicarb pesticide based on the immobilization of laccase on composite carbon paste electrodes. Multi-walled carbon nanotubes (MWCNTs) paste electrode modified by dispersion of laccase (3%, w/w) within the optimum composite matrix (60:40%, w/w, MWCNTs and paraffin binder) showed the best performance, with excellent electron transfer kinetic and catalytic effects related to the redox process of the substrate 4-aminophenol. No metal or anti-interference membrane was added. Based on the inhibition of laccase activity, pirimicarb can be determined in the range 9.90 × 10(-7) to 1.15 × 10(-5) mol L(-1) using 4-aminophenol as substrate at the optimum pH of 5.0, with acceptable repeatability and reproducibility (relative standard deviations lower than 5%). The limit of detection obtained was 1.8 × 10(-7) mol L(-1) (0.04 mg kg(-1) on a fresh weight vegetable basis). The high activity and catalytic properties of the laccase-based biosensor are retained during ca. one month. The optimized electroanalytical protocol coupled to the QuEChERS methodology were applied to tomato and lettuce samples spiked at three levels; recoveries ranging from 91.0 ± 0.1% to 101.0 ± 0.3% were attained. No significant effects in the pirimicarb electroanalysis were observed by the presence of pro-vitamin A, vitamins B1 and C, and glucose in the vegetable extracts. The proposed biosensor-based pesticide residue methodology fulfills all requisites to be used in implementation of food safety programs.

This study reports the levels of nitrate and nitrite of 34 vegetable samples, including different varieties of cabbage, lettuce, spinaches, parsley and turnips, collected in several locations of an intensive agricultural area (Modivas, Vila do Conde, northern Portugal). Nitrate levels ranged between 54 and 2440 mg NO 3 - kg −1 , while nitrite levels ranged between 1.1 and 57 mg NO 2 - kg −1 . The maximum residue levels established for nitrate in spinach and lettuce samples were not exceeded. Nitrate and nitrite levels reported in the literature for the same type of samples are reviewed, as well as the contribution of vegetables to nitrate and nitrite dietary exposure of populations.

Regardless the controversies surrounding genetically modified organisms (GMO), their cultivation isconstantly increasing and in according to the EU legislation, labeling is mandatory for products con-taining EU-authorized-GMO higher than 0.9%. Thereby, new analytical strategies for rapid and effectivedetection of GMO on foodstuffs are required. In this work, an electrochemical immunosensor foreffective determination of Cry1Ab protein from MON810 transgenic maize (EU-authorized-GMO) isdescribed. The immunosensor was developed onto indium tin oxide (ITO) electrodes modified by3-aminopropyltrimethoxysilane (APTES) monolayer to covalently immobilize Anti-Cry1Ab polyclonalantibodies. The protein interaction with the polyclonal antibody (PAb) recognition platform was directlymonitored and measured by cyclic voltammetry and electrochemical impedance spectroscopy usingcommercially Cry1Ab protein. After the analytical features optimization a linear response from 1 to10 ng mL−1, a limit of detection (LOD) of 0.37 ng mL−1and a limit of quantification (LOQ) of 1.23 ng mL−1– which provided accurate results (RSD < 7.5%) – were achieved. The immunosensor allowed a simple andfast detection of Cry1Ab protein extracted from maize seeds with different GM maize mass percentages(0%, 0.5%, 1%, 2.5% and 5%). To crosscheck the detection of Cry1Ab protein, an enzyme-linked immunosor-bent assay (ELISA) was used. The results indicate that the immunosensor is suitable for the transgenicprotein Cry1Ab detection in GM maize representing a successfully tool to verify the compliance of theEU regulations.

Simple, cost-effective and reliable tools for the quantification of genetically modified organisms (GMO) in food and feed are highly demanded to enforce labelling legislation in the EU. Herein, we report a novel method for quantitative analysis of genetically modified soybean with the event GTS-40-3-2, also known as Roundup Ready (RR) soybean, using magnetoassays with electrochemical detection, coupled to DNA amplification by end-point polymerase chain reaction (PCR). For the proposed work, two DNA sequences were targeted via hybridisation onto magnetic beads, one specific for the transgenic event and the other for the taxon or species-specific lectin gene. Enzymatic labelling was performed to obtain an electrochemically active product measured by chronoamperometry. By optimising the number of PCR cycles, among other parameters, two magnetoassays coupled to PCR were successfully accomplished and linearity was obtained in the ranges of 53–4425 and 1093–88,496 DNA copies for the event-specific and lectin sequences, respectively. The proposed method provides accurate and precise RR soybean quantitative results, being effectively compared to those obtained by real-time PCR, as the reference method. These findings confirm the suitability of the method as an alternative tool for GMO quantification.

The electroreduction behaviour of cysteine was investigated using cyclic, square wave and differencial pulse voltammetric techniques at a platinum working electrode. The reduction of cysteine occurs at a potential of -0.36 V independent of pH. It is a reversible process, controlled mainly by diffusion and in the mechanism of reduction 1 electron per molecule is involved. Using the voltammetric techniques: Cyclic Voltammetry, Square Wave Voltammetry and Differencial Pulse Voltammetry, different parameters (pH, frequency, step potential, pulse amplitude, scan rate) were optimized in order to develop an electrochemical procedure for determination of cysteine in pharmaceutical products. The repeatability, reproducibility, precision and accuracy of the methods were studied. No electroactive interferences from the excipient were found in the pharmaceutical compounds.

A novel electrochemical sensor for ochratoxin A (OTA) detection was fabricated through the modification of a glassy carbon electrode (GCE) with multiwalled carbon nanotubes (MWCNTs) and a molecularly imprinted polymer (MIP). The MWCNTs dramatically promoted the sensitivity of the developed sensor, while polypyrrole (PPy) imprinted with OTA served as the selective recognition element. The imprinted PPy film was prepared by electropolymerization of pyrrole in the presence of OTA as a template molecule via cyclic voltammetry (CV). The electrochemical oxidation of OTA at the developed sensor was investigated by CV and differential pulse voltammetry (DPV). The developed MIP/MWCNT/GCE sensor showed a linear relationship, when using DPV, between peak current intensity and OTA concentration in the range between 0.050 and 1.0 μM, with limits of detection (LOD) and quantification of 0.0041 μM (1.7 μg/L) and 0.014 μM (5.7 μg/L) respectively. With the developed sensor precise results were obtained; relative standard deviations of 4.2% and 7.5% in the evaluation of the repeatability and reproducibility, respectively. The MIP/MWCNT/GCE sensor is simple to fabricate and easy to use and was successfully applied to the determination of OTA in spiked beer and wine samples, with recoveries between 84 and 104%, without the need of a sample pre-treatment step.

A detailed study of voltammetric behavior of ethiofencarb (ETF) is reported using glassy carbon electrode (GCE) and hanging mercury drop electrode (HMDE). With GCE, it is possible to verify that the oxidative mechanism is irreversible, independent of pH, and the maximum intensity current was observed at +1.20 V vs. AgCl/Ag at pH 1.9. A linear calibration line was obtained from 1.0x10-4 to 8.0x10-4 mol L-1 with SWV method. To complete the electrochemical knowledge of ETF pesticide, the reduction was also explored with HMDE. A well-defined peak was observed at –1.00V vs. AgCl/Ag in a large range of pH with higher signal at pH 7.0. Linearity was obtained in 4.2x10-6 and 9.4x10-6 mol L-1 ETF concentration range. An immediate alkaline hydrolysis of ETF was executed, producing a phenolic compound (2-ethylthiomethylphenol) (EMP), and the electrochemical activity of the product was examined. It was deduced that it is oxidized on GCE at +0.75V vs. AgCl/Ag with a maximum peak intensity current at pH 3.2, but the compound had no reduction activity on HMDE. Using the decrease of potential peak, a flow injection analysis (FIA) system was developed connected to an amperometric detector, enabling the determination of EMP over concentration range of 1.0x10-7 and 1.0x10-5 mol L-1 at a sampling rate of 60 h-1. The results provided by FIA methodology were performed by comparison with results from high-performance liquid chromatography (HPLC) technique and demonstrated good agreement with relative deviations lower than 4%. Recovery trials were performed and the obtained values were between 98 and 104%.

Food allergens are a real threat to sensitized individuals. Although food labeling is crucial to provide information to consumers with food allergies, accidental exposure to allergenic proteins may result from undeclared allergenic substances by means of food adulteration, fraud or uncontrolled cross-contamination. Allergens detection in foodstuffs can be a very hard task, due to their presence usually in trace amounts, together with the natural interference of the matrix. Methods for allergens analysis can be mainly divided in two large groups: the immunological assays and the DNA-based ones. Mass spectrometry has also been used as a confirmatory tool. Recently, biosensors appeared as innovative, sensitive, selective, environmentally friendly, cheaper and fast techniques (especially when automated and/or miniaturized), able to effectively replace the classical methodologies. In this review, we present the advances in the field of food allergens detection toward the biosensing strategies and discuss the challenges and future perspectives of this technology.

In the present work, the development of a genosensor for the event-specific detection of MON810 transgenic maize is proposed. Taking advantage of nanostructuration, a cost-effective three dimensional electrode was fabricated and a ternary monolayer containing a dithiol, a monothiol and the thiolated capture probe was optimized to minimize the unspecific signals. A sandwich format assay was selected as a way of precluding inefficient hybridization associated with stable secondary target structures. A comparison between the analytical performance of the Au nanostructured electrodes and commercially available screen-printed electrodes highlighted the superior performance of the nanostructured ones. Finally, the genosensor was effectively applied to detect the transgenic sequence in real samples, showing its potential for future quantitative analysis.