https://hdl.handle.net/10481/47205 Sat, 11 Apr 2026 18:53:02 GMT 2026-04-11T18:53:02Z 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/10481/104114 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/10481/103985 Photochromic polyoxometalate–based enzyme-free reusable sensors for real-time colorimetric detection of alcohol in sweat and saliva Sánchez del Castillo, Manuel José; González Garnica, Ana Isabel; Sabio Rodríguez, Laura; Zou, Wenyue; Ramanathan, Rajesh; Bansal, Vipul; Domínguez Vera, José Manuel This study describes a new strategy for real-time detection of alcohol in saliva and sweat. Phosphotungstic acid (PTA) is a colorless, photoelectrochromic heteropoly acid that can be reduced by ethanol under ultraviolet (UV) radiation to produce an intense blue color. This system has useful properties in the development of a new alcohol sensor: (1) the blue color can be detected by the naked eye or mobile camera, even at low ethanol concentrations; (2) color intensity is proportional to ethanol concentration; and (3) once exposed to air, reduced PTA is subsequently oxidized and returns to its colorless state offering sensor reusability. Based on these properties, we developed a simple device consisting of a PTA-impregnated non-woven material and a low-cost UV lamp that can be used to evaluate the alcohol concentration in saliva and sweat. We further enhanced the practical applicability of this sensor by demonstrating the integration of digital image analysis, multivariate analysis, and mobile camera technology with this sensor. This device can be potentially used in vehicles as a convenient, reusable alcohol sensor for drivers. This work was funded by the Spanish Ministerio de Ciencia, Innovación y Universidades (MICIU) (project FEDER PID2019-111461 GB-I00). A.G. acknowledges Junta de Andalucía for the postdoctoral contract within the PAIDI 2020 program (DOC_00791). L.S. acknowledges the Spanish MICIU for the predoctoral contract within the FPU program (FPU16/01360). The authors also thank the ‘Unidad de Excelencia Química aplicada a Biomedicina y Medioambiente’ (UGR) for funding support. V.B. acknowledges Ian Potter Foundation for establishing Sir Ian Potter NanoBioSensing Facility at RMIT University. https://hdl.handle.net/10481/103985 https://hdl.handle.net/10481/99300 Entrapping living probiotics into collagen scaffolds: a new class of biomaterials for antibiotic-free therapy of bacterial vaginosis González Garnica, Ana Isabel; Sabio Rodríguez, Laura; Hurtado Morales, Carmen; Ramírez Rodríguez, Gloria Belén; Bansal, Vipul; Delgado López, José Manuel; Domínguez Vera, José Manuel A new concept of biomaterials for antibiotic-free therapy of bacterial vaginosis (BV) is here proposed. These biomaterials are obtained by entrapping two probiotic biofilms, viz., Lactobacillus fermentum (Lf ) and Lactobacillus acidophilus (La) into scaffolds of self-assembled collagen fibers (col). An in-depth characterization and viability assays are performed on the resulting biomaterials. Results demonstrated that the collagen matrix plays a multifold role in improving the probiotic efficacy in a BV-simulated environment: i) it acts as a host to the formation of the probiotic biofilm, ii) it protects live probiotics during storage under harsh conditions, iii) it enhances the metabolic activity of entrapped probiotics thereby restoring the pH of BV-simulated microenvironment, and iv) it enhances the adhesion of probiotics to the simulated vaginal mucosa. These collective properties make these biomaterials as promising candidates for treating BV without antibiotics. In addition, the approach here presented can be adapted for the treatment of other complex microbial infections. https://hdl.handle.net/10481/99300