https://hdl.handle.net/10481/47204 Fri, 17 Apr 2026 02:53:44 GMT 2026-04-17T02:53:44Z https://hdl.handle.net/10481/109228 Electrochromic polyoxometalates for sensing abiotic stress in plants González Garnica, Ana Isabel; Pérez Gordillo, Felipe; Alarcón Guijo, Pablo; Romero Puertas, María; Sandalio González, Luisa María; Domínguez Vera, José Manuel Introduction: Understanding plant responses to abiotic stress requires an insight into plant redox activity. This study proposes a novel and cost-effective method for assessing the redox state of plants. Methods: The method utilizes the electrochromic properties of polyoxometalate phosphomolybdic acid hydrate (PMA). PMA is reduced proportionally by glutathione (GSH) and ascorbic acid (AsA), which results in a measurable color change. The validity of this method was confirmed through empirical experimentation in Arabidopsis thaliana under conditions of salinity and UV radiation. Results: Salinity treatments revealed a non-significant, two-phase trend in redox activity with an increase at moderate levels followed by a decrease. UVC radiation led to a substantial decrease in redox activity, indicating distress. In contrast, UVA promoted resilience, also known as eustress. Notably, UVB significantly increased redox activity, suggesting the activation of an emergency antioxidant response. Discussion: A demonstrable correlation has been identified between the redox activity of plants and various stress types. This correlation facilitates the classification of responses into two distinct categories: adaptive eustress and detrimental distress. This advancement contributes to the enhancement of plant metabolic and stress tolerance evaluation. https://hdl.handle.net/10481/109228 https://hdl.handle.net/10481/104118 Materiales fotoelectrocrómicos como sensores de biomeléculas Guerrero Ortega, Emma Los polioxometalatos (POMs) son materiales electrocrómicos descritos como clústeres aniónicos o fragmentos moleculares de óxidos metálicos capaces de aceptar electrones mediante procesos químicos o fotoquímicos, dando lugar a especies coloreadas de valencia mixta. Los organismos vivos y algunas biomoléculas pueden actuar como donantes de electrones para estos materiales, de modo que las propiedades cromáticas de los POMs pueden relacionarse directamente con una determinada actividad biológica o con la presencia de una biomolécula en una determinada muestra. Esta propiedad los hace candidatos ideales para el diseño de sensores colorimétricos. Un campo de posible aplicación de este tipo de sensor podría ser en agricultura, ya que el uso de fertilizantes, es a día de hoy el único recurso para mantener la correcta nutrición de plantas y cultivos. Sin embargo, el aprovechamiento de los mismos no es total y esto hace que numerosos iones inorgánicos (sobre todo nitratos, nitritos y amonios) queden en exceso en suelos o que lleguen a contaminar aguas. En la búsqueda de alternativas que permitan evitar estos procesos contaminantes, está la rápida detección del exceso de sales inorgánicas. En este sentido, este trabajo pretende diseñar un nuevo sensor colorimétrico basado en el empleo de las propiedades colorimétricas de los POMs para la detección de nitratos, nitritos y amonios de forma más rápida, sencilla y económica que los métodos tradicionales existentes para el mismo fin. https://hdl.handle.net/10481/104118 https://hdl.handle.net/10481/104114 Magnetic and golden yogurts. Food as a Potential Nanomedicine Carrier Garcés Robles, Víctor Jesús; González Garnica, Ana Isabel; Sabio Rodríguez, Laura; Sánchez-Arévalo, Carmen María; Gálvez Rodríguez, Natividad; Domínguez Vera, José Manuel Yogurt is one of the most emblematic and popular fermented foods. It is produced by the fermentation of milk lactose by bacteria such as Streptococcus thermophilus and Lactobacillus acidophilus. Magnetic (MNPs) and gold nanoparticles (AuNPs) were incorporated into the exopolysaccharides (EPSs) of these bacteria. The functionalized bacteria were characterized by UV-vis spectroscopy and transmission electron microscopy. A large number of MNPs and AuNPs were bound to the bacterial EPS. Interestingly, the nanoparticles’ (NPs) presence did not a ect the bacteria’s capacity to ferment milk and to produce magnetic and golden yogurts. Magnetic and golden yogurts represent the perfect combination of emblematic food and nanoparticles and have a range of potential biomedical applications: use in iron-deficiency anemia, diagnosis and hyperthermia treatment of appropriate digestive diseases, and interest in glamour cuisine. This research was funded by the Spanish Ministry of Science, Innovation, and Universities (MICINN) (project FEDER CTQ2015-64538-R). The authors also thank the “Unidad de Excelencia Química aplicada a Biomedicina y Medioambiente” (UGR) for funding and support.; Supplementary Materials: The following are available online at http://www.mdpi.com/1996-1944/13/2/481/s1 https://hdl.handle.net/10481/104114 https://hdl.handle.net/10481/104004 Photoinduced electron transfer cascade between Mo- and W-based polyoxometalates Sánchez del Castillo, Manuel José; González Garnica, Ana Isabel; Guerrero Ortega, Emma; Bansal, Vipul; Domínguez Vera, José Manuel The Keggin-type polyoxometalates phosphotungstic acid (PTA, H3PW12O40) and phosphomolybdic acid (PMA, H3PMo12O40) can undergo reduction through chemical and photochemical methods. However, the higher electron affinity of Mo(VI) relative to W(VI) and the higher LUMO delocalisation in PTA result in different redox behaviours of the two polyoxometalates. We have identified specific experimental conditions that allow for the photoreduction of PTA in the presence of UV radiation and an electron donor, such as isopropanol (IPA), while PMA does not undergo this reaction. This distinct redox behaviour of polyoxometalates has been leveraged to develop a photoinduced electron transfer cascade from PTA to PMA that can be switched on and off by light. To demonstrate the unique capabilities of this transfer, the mimicry of the early stages of photosynthesis has been achieved by introducing the redox pair benzoquinone (BQ)-hydroquinone (HQ) between PTA and PMA. The transient photoexcitation of the four-component PTA–BQ–HQ–PMA system in the presence of IPA, triggered a cascade of reactions. Initially, PTA was reduced to PTAred, which, under dark conditions, could reduce BQ to HQ. HQ then reduced PMA to PMAred. This cascade of reactions, akin to the first stage of photosynthesis, was facilitated by the generation of a proton (H+) gradient through the spatial separation of the positive holes created at the PTA terminal and the excited electron migrated across the cascade and localized at the PMAred terminal. This represents the first example of a unidirectional photo-induced electron transfer cascade between four molecular components. https://hdl.handle.net/10481/104004 https://hdl.handle.net/10481/103990 Érase una vez el hierro Sabio Rodríguez, Laura; González Garnica, Ana Isabel; Domínguez Vera, José Manuel Grupo de Investigación FQM-368, BioNanoMetals. Departamento de Química Inorgánica, Facultad de Ciencias (Universidad de Granada). Avenida Fuente Nueva s/n, 18071, Granada, España (2022). https://hdl.handle.net/10481/103990