Persona: González Crevillén, Agustín
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González Crevillén
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Publicación Effect of nanocellulose polymorphism on electrochemical analytical performance in hybrid nanocomposites with non‑oxidized single‑walled carbon nanotubes(Springer, 2022-06-14) Dortez, Silvia; Sierra, Tania; Álvarez‑Sánchez, Miguel Á.; González‑Domínguez, José M.; Benito, Ana M.; Maser, Wolfgang K.; González Crevillén, Agustín; Escarpa, AlbertoTwo cellulose nanocrystals/single-walled carbon nanotube (CNC/SW) hybrids, using two cellulose polymorphs, were evaluated as electrochemical transducers: CNC type I (CNC-I/SW) and CNC type II (CNC-II/SW). They were synthesized and fully characterized, and their analytical performance as electrochemical sensors was carefully studied. In comparison with SWCNT-based and screen-printed carbon electrodes, CNC/SW sensors showed superior electroanalytical performance in terms of sensitivity and selectivity, not only in the detection of small metabolites (uric acid, dopamine, and tyrosine) but also in the detection of complex glycoproteins (alpha-1-acid glycoprotein (AGP)). More importantly, CNC-II/SW exhibited 20 times higher sensitivity than CNC-I/SW for AGP determination, yielding a LOD of 7 mg L −1 .These results demonstrate the critical role played by nanocellulose polymorphism in the electrochemical performance of CNC/SW hybrid materials, opening new directions in the electrochemical sensing of these complex molecules. In general, these high-active-surface hybrids smartly exploited the preserved non-oxidized SW conductivity with the high aqueous dispersibility of the CNC, avoiding the use of organic solvents or the incorporation of toxic surfactants during their processing, making the CNC/SW hybrids promising nanomaterials for electrochemical detection following greener approaches.Publicación Paper-Based Analytical Devices for Accurate Assessment of Transferrin Saturation in Diagnosed Clinical Samples from Ischemic Stroke Patients(ACS, 2023-07-23) Dortez, Silvia; DeGregorio-Rocasolano, Núria; Millán, Mònica; Gasull, Teresa; González Crevillén, Agustín; Escarpa, AlbertoFor the first time, a paper-based analytical device (PAD) was developed for the assessment of transferrin saturation (TSAT), which is defined as the ratio between iron bound to transferrin (Tf) and the total iron-binding capacity (TIBC) of Tf. Both parameters were simultaneously measured on the same PAD using ferrozine as a chromophore and a smartphone as the color reader. To this end, Tf was first isolated from serum using anti-Tf immunomagnetic beads to ensure that only the Tf-bound iron was measured, improving the selectivity and accuracy of TSAT assessment. To demonstrate the practical utility of the device, it was validated by analyzing a certified reference material, showing excellent accuracy (Er < 4%) and good precision (RSD ≤ 6%). Finally, 18 diagnosed serum samples from ischemic stroke patients were analyzed by this approach, and the results were compared with those obtained by urea-PAGE, showing not only an excellent correlation (r = 0.93, p < 0.05) but that the PAD approach has become statistically identical to the free-interference urea-PAGE. In comparison with the slow, tedious, and non-miniaturized-PAGE, this PAD approach exhibited attractive characteristics such as low cost, disposability, and connectivity, showing great potential for future point-of-care testing, especially in developing countries and/or remote areas, where access to medical or clinical facilities is limited.Publicación A dual colorimetric-electrochemical microfluidic paper-based analytical device for point-of-care testing of ischemic strokes(The Royal Society of Chemistry, 2024-07-29) Dortez, Silvia; Pacheco, Marta; Gasull, Teresa; González Crevillén, Agustín; Escarpa, AlbertoA novel microfluidic paper-based analytical device with dual colorimetric and electrochemical detection (dual μPAD) was developed for the assessment of transferrin saturation (TSAT) in samples from ischemic stroke patients. TSAT was calculated from the ratio between transferrin-bound iron, which was colorimetrically measured, and the total iron-binding capacity, which was electrochemically measured. To this end, a μPAD was smartly designed, which integrated both colorimetric and electrochemical detection reservoirs, communicating via a microchannel acting as a chemical reactor, and with preloading/storing capabilities (reagent-free device). This approach allowed the dual and simultaneous determination of both parameters, providing an improvement in the reliability of the results due to an independent signal principle and processing. The μPADs were validated by analyzing a certified reference material, showing excellent accuracy (Er ≤ 5%) and precision (RSD ≤ 2%). Then they were applied to the analysis of diagnosed serum samples from ischemic stroke patients. The results were compared to those provided by a free-interference method (urea-PAGE). Impressively, both methods exhibited a good correlation (r = 0.96, p < 0.05) and no significant differences were found between them (slope 1.0 ± 0.1 and the intercept 1 ± 4, p < 0.05), demonstrating the excellent accuracy of our approach during the analysis of complex samples from ischemic stroke patients, using just 90 μL of clinical samples and taking less than 90 min in comparison with the 18 hours required by the urea-PAGE approach. The developed fully integrated colorimetric-electrochemical μPAD is a promising ready to use reagent-free device for the point-of-care testing of TSAT, which can be used to assist physicians in the fast diagnosis and prognosis of ischemic strokes, where the decision-time is crucial for the patient's survival.Publicación Electroanalytical paper-based device for reliable detection and quantification of sugars in milk(Elsevier, 2024-01-01) Dortez, Silvia; González Crevillén, Agustín; Escarpa, Alberto; Cinti, StefanoKnowing the level of sugars in food and beverages is essential because they are related to diseases such as diabetes, and obesity, among others. In this regard, an approach has been designed, characterized, and applied to develop the first all-in-one paper-based microfluidic analytical device for the quantification of sugars in milk samples. In particular, the powerful combination of the paper-based platform, the facile manufacturing, and the on-demand customization, allowed to obtain a stand-alone platform that was capable to store all the reagents necessary for the assay, to treating the sample by removing major interferences due to lipids and proteins, and to visualize the results in minutes. A wax-patterned chromatographic paper was finely designed to provide a reagent-free platform for the use of non-specialists applied towards the analysis of sugars' content (lactose as the main sugar). Sugars were electrochemically quantified down to 0.16 g L−1 with a repeatability of 5%. To strengthen the efficacy of the novel platform, the electrochemical paper-based analytical device has been applied to commercial milk, including skimmed, semi-skimmed, whole, and lactose-free, confirming satisfactory performance with analytical reliability. This paper-based architecture opens novel avenues for portable (bio)sensing of other relevant species, not only in the agri-food field.Publicación Pump-Free Microfluidic Device for the Electrochemical Detection of α1-Acid Glycoprotein(American Chemical Society Publications, 2021-07-05) Tania, Sierra; Jang, Ilhoon; Noviana, Eka; González Crevillén, Agustín; Escarpa, Alberto; S. Henry, Charlesα1-Acid glycoprotein (AGP) is a glycoprotein present in serum, which is associated with the modulation of the immune system in response to stress or injuries, and a biomarker for inflammatory diseases and cancers. Here, we propose a pump-free microfluidic device for the electrochemical determination of AGP. The microfluidic device utilizes capillary-driven flow and a passive mixing system to label the AGP with the Os (VI) complex (an electrochemical tag) inside the main channel, before delivering the products to the electrode surface. Furthermore, thanks to the resulting geometry, all the analytical steps can be carried out inside the device: labeling, washing, and detection by adsorptive transfer stripping square wave voltammetry. The microfluidic device exhibited a linear range from 500 to 2000 mg L–1 (R2 = 0.990) and adequate limit of detection (LOD = 231 mg L–1). Commercial serum samples were analyzed to demonstrate the success of the method, yielding recoveries around 83%. Due to its simplicity, low sample consumption, low cost, short analysis time, disposability, and portability, the proposed method can serve as a point-of-care/need testing device for AGP.Publicación Integrated calibration and serum iron in situ analysis into an array microfluidic paper-based analytical device with smartphone readout(Elsevier, 2023-09-07) Dortez, Silvia; González Crevillén, Agustín; Escarpa, AlbertoIn this work, a colorimetric microfluidic paper-based analytical device (μPAD) combined with a smartphone readout was proposed for the determination of serum iron (Fe3+), which is linked to transferrin. Firstly, Fe3+ was selectively isolated and preconcentrated from serum by using anti-transferrin immunomagnetic beads (anti-Tf-MBs). Secondly, Fe3+ is reduced to Fe2+ by a hydroxylamine solution (pH 4.8) and then measured in the μPAD, which contains the colorimetric reagent ferrozine. Finally, the intensity of the purple color formed in the μPAD was measured by a smartphone. The approach exhibited an excellent linear correlation (r = 0.996) and good limit of detection (0.3 μg mL−1). Moreover, a certified reference material (human serum) was analyzed by this approach, showing an excellent accuracy (Er < 4%) and inter-device reproducibility (RSD = 1%, n = 3). Interestingly, the μPAD array-design allowed the simultaneous analysis of different samples, improving the sample throughput (up to 5 samples in 130 min, using 100 μL each), and the integration of calibration and analysis into the same device, simplifying the analysis without losing accuracy or sensitivity, and avoiding inter-device variability, which constituted an added value to this approach. These disposable μPADs meet several requirements of point-of-care testing (POCT) because it is cheap, portable, easy-to-use, sensitive, and specific. Therefore, it may be an interesting way for measuring patients’ serum iron levels in situ with reliability, especially, in developing countries, where the prevalence of iron deficiency and iron-deficiency anemia is higher and there are lower health resources than in developed countries.