Screen-printed Organic Electrochemical Transistors for the detection of ascorbic acid in food

[EN] Methods traditionally used for ascorbic acid (AA) detection in food are often expensive and complex, making them unsuitable for day-to-day determinations. In this work, we report on the use of all- PEDOT:PSS Organic Electrochemical Transistors (OECTs) for fast, simple and low-cost determination of AA in food. The performance of these OECTs was tested first with in lab-prepared solutions of AA with different concentrations. The effect of the geometry on the transistors performance for AA sensing was also investigated by comparing the response of two OECTs with different channel and gate areas ratio (g), in terms of current modulation, sensitivity, background signal and limit of detection (LOD). OECTs with smaller gate electrode than the channel (large g) show the best performance for AA sensing: these devices display smaller background signal, higher sensitivity, larger modulation and better LOD value (80.10^-6 M). Since the AA content in food rich in Vitamin C is in the mM range, these transistors can be considered sensitive enough for quantitatively monitoring AA in food. In order to demonstrate the reliability of the proposed sensors in real food samples, the response of these transistors was additionally measured in a commercial orange juice. The amount of AA obtained with the OECTs is in good agreement with that determined by HPLC and with values reported in the literature for orange juices. Furthermore, these OECTs can be considered promising candidates for the selective detection of AA in the presence of other interfering antioxidants.This work was supported by Spanish Government/FEDER funds (grant number MAT2015-64139-C4-3-R (MINECO/FEDER)) and Generalitat Valenciana funds (grant number AICO/2015/103).Contat-Rodrigo, L.; Pérez Fuster, C.; Lidon-Roger, JV.; Bonfiglio, A.; Garcia-Breijo, E. (2017). Screen-printed Organic Electrochemical Transistors for the detection of ascorbic acid in food. Organic Electronics. 45:89-96. https://doi.org/10.1016/j.orgel.2017.02.03789964

Characterization of Screen-Printed Organic Electrochemical Transistors to Detect Cations of Different Sizes

[EN] A novel screen-printing fabrication method was used to prepare organic electrochemical transistors (OECTs) based on poly(3,4-ethylenedioxythiophene) doped with polysterene sulfonate (PEDOT:PSS). Initially, three types of these screen-printed OECTs with a different channel and gate areas ratio were compared in terms of output characteristics, transfer characteristics, and current modulation in a phosphate buffered saline (PBS) solution. Results confirm that transistors with a gate electrode larger than the channel exhibit higher modulation. OECTs with this geometry were therefore chosen to investigate their ion-sensitive properties in aqueous solutions of cations of different sizes (sodium and rhodamine B). The effect of the gate electrode was additionally studied by comparing these all-PEDOT:PSS transistors with OECTs with the same geometry but with a non-polarizable metal gate (Ag). The operation of the all-PEDOT:PSS OECTs yields a response that is not dependent on a Na+ or rhodamine concentration. The weak modulation of these transistors can be explained assuming that PEDOT:PSS behaves like a supercapacitor. In contrast, the operation of Ag-Gate OECTs yields a response that is dependent on ion concentration due to the redox reaction taking place at the gate electrode with Cl− counter-ions. This indicates that, for cation detection, the response is maximized in OECTs with non-polarizable gate electrodes.Financial support from FEDER and Spanish Government funds (MAT2015-64139-C4-3-R (MINECO/FEDER)) and GVA funds (AICO/2015/103) are gratefully acknowledged.Contat-Rodrigo, L.; Pérez Fuster, C.; Lidon-Roger, JV.; Bonfiglio, A.; Garcia-Breijo, E. (2016). Characterization of Screen-Printed Organic Electrochemical Transistors to Detect Cations of Different Sizes. Sensors. 16(10). https://doi.org/10.3390/s16101599S15991610Shirakawa, H., Louis, E. J., MacDiarmid, A. 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Advanced Materials, 14(20), 1460-1464. doi:10.1002/1521-4095(20021016)14:203.0.co;2-sBasiricò, L., Cosseddu, P., Scidà, A., Fraboni, B., Malliaras, G. G., & Bonfiglio, A. (2012). Electrical characteristics of ink-jet printed, all-polymer electrochemical transistors. Organic Electronics, 13(2), 244-248. doi:10.1016/j.orgel.2011.11.010Bernards, D. A., & Malliaras, G. G. (2007). Steady-State and Transient Behavior of Organic Electrochemical Transistors. Advanced Functional Materials, 17(17), 3538-3544. doi:10.1002/adfm.200601239Nikolou, M., & Malliaras, G. G. (2008). Applications of poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonic acid) transistors in chemical and biological sensors. The Chemical Record, 8(1), 13-22. doi:10.1002/tcr.20133Nilsson, D., Robinson, N., Berggren, M., & Forchheimer, R. (2005). Electrochemical Logic Circuits. Advanced Materials, 17(3), 353-358. doi:10.1002/adma.200401273Lin, P., Yan, F., & Chan, H. L. W. (2010). 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Integration of a 2D Touch Sensor with an Electroluminescent Display by Using a Screen-Printing Technology on Textile Substrate

[EN] Many types of solutions have been studied and developed in order to give the user feedback when using touchpads, buttons, or keyboards in textile industry. Their application on textiles could allow a wide range of applications in the field of medicine, sports or the automotive industry. In this work, we introduce a novel solution that combines a 2D touchpad with an electroluminescent display (ELD). This approach physically has two circuits over a flexible textile substrate using the screen-printing technique for wearable electronics applications. Screen-printing technology is widely used in the textile industry and does not require heavy investments. For the proposed solution, different layer structures are presented, considering several fabric materials and inks, to obtain the best results.This work was supported by Spanish Government/FEDER funds (grant number MAT2015-64139-C4-3-R (Mineco/Feder)). The work presented is also funded by the Conselleria d'Economia Sostenible, Sectors Productius i Treball, through IVACE (Instituto Valenciano de Competitividad Empresarial) and cofounded by ERDF funding from the EU. Application No.: IMAMCI/2017/1.Ferri Pascual, J.; Pérez Fuster, C.; Llinares Llopis, R.; Moreno Canton, J.; Garcia-Breijo, E. (2018). Integration of a 2D Touch Sensor with an Electroluminescent Display by Using a Screen-Printing Technology on Textile Substrate. Sensors. 18(10):3313-3326. https://doi.org/10.3390/s18103313S33133326181

Early Detection of Freeze Damage in Navelate Oranges with Electrochemical Impedance Spectroscopy

[EN] The early detection of freeze damage in Navelate oranges (Citrus sinensis L. Osbeck) was studied using electrochemical impedance spectroscopy (EIS), which is associated with a specific double-needle sensor. The objective was to identify this problem early in order to help to determine when a freeze phenomenon occurs. Thus, we selected a set of Navelate oranges without external defects, belonging to the same batch. Next, an intense cold process was simulated to analyze the oranges before and after freezing. The results of the spectroscopy analysis revealed different signals for oranges depending on whether they had experienced freezing or not. Principal Component Analysis (PCA) and Partial Least Squares-Discriminant Analysis (PLS-DA) of the obtained data demonstrated that it is possible to discriminate the samples, explaining 88.5% of the total variability (PCA) and being able to design a mathematical model with a prediction sensitivity of 80% (PLS-DA). Additionally, a designed artificial neural network (ANN) prediction model managed to correctly classify 100% of the studied samples. Therefore, EIS together with ANN-based data treatment is proposed as a viable alternative to the traditional techniques for the early detection of freeze damage in oranges.This research was funded by the Ministerio de Economia y Competitividad of the Spanish Government and European FEDER funds (MAT2015-64139-C4-3-R (MINECO/FEDER)) and the Conselleria d'Educacio, Investigacio, Cultura i Esport de la Gereralitat Valenciana (GV/2018/090).Serrano-Pallicer, E.; Muñoz-Albero, M.; Pérez Fuster, C.; Masot Peris, R.; Laguarda-Miro, N. (2018). Early Detection of Freeze Damage in Navelate Oranges with Electrochemical Impedance Spectroscopy. Sensors. 18(12):1-10. https://doi.org/10.3390/s18124503S110181

Mutations, Genes, and Phenotypes Related to Movement Disorders and Ataxias

26 páginas, 4 figuras, 3 tablasOur clinical series comprises 124 patients with movement disorders (MDs) and/or ataxia with cerebellar atrophy (CA), many of them showing signs of neurodegeneration with brain iron accumulation (NBIA). Ten NBIA genes are accepted, although isolated cases compatible with abnormal brain iron deposits are known. The patients were evaluated using standardised clinical assessments of ataxia and MDs. First, NBIA genes were analysed by Sanger sequencing and 59 patients achieved a diagnosis, including the detection of the founder mutation PANK2 p.T528M in Romani people. Then, we used a custom panel MovDisord and/or exome sequencing; 29 cases were solved with a great genetic heterogeneity (34 different mutations in 23 genes). Three patients presented brain iron deposits with Fe-sensitive MRI sequences and mutations in FBXO7, GLB1, and KIF1A, suggesting an NBIA-like phenotype. Eleven patients showed very early-onset ataxia and CA with cortical hyperintensities caused by mutations in ITPR1, KIF1A, SPTBN2, PLA2G6, PMPCA, and PRDX3. The novel variants were investigated by structural modelling, luciferase analysis, transcript/minigenes studies, or immunofluorescence assays. Our findings expand the phenotypes and the genetics of MDs and ataxias with early-onset CA and cortical hyperintensities and highlight that the abnormal brain iron accumulation or early cerebellar gliosis may resembling an NBIA phenotype.This work was supported by the Instituto de Salud Carlos III (ISCIII)—Subdirección General de Evaluación y Fomento de la Investigación within the framework of the National R + D+I Plan co-funded with European Regional Development Funds (ERDF) [Grants PI18/00147 and PI21/00103 to CE]; the Fundació La Marató TV3 [Grants 20143130 and 20143131 to BPD and CE]; and by the Generalitat Valenciana [Grant PROMETEO/2018/135 to CE]. Part of the equipment employed in this work was funded by Generalitat Valenciana and co-financed with ERDF (OP ERDF of Comunitat Valenciana 2014–2020). PS had an FPU-PhD fellowship funded by the Spanish Ministry of Education, Culture and Sport [FPU15/00964]. IH has a PFIS-PhD fellowship [FI19/00072]. ASM has a contract funded by the Spanish Foundation Per Amor a l’Art (FPAA)Peer reviewe