FQM118 - Artículos
https://hdl.handle.net/10481/47941
2024-03-29T00:34:13ZThread-based microfluidic sensor for lithium monitoring in saliva
https://hdl.handle.net/10481/78226
Thread-based microfluidic sensor for lithium monitoring in saliva
Erenas Rodríguez, Miguel María; Capitán Vallvey, Luis Fermín; Lewinska, Izabela
Lithium administration is a commonly prescribed treatment for some mental disorders, e.g. bipolar disorder. However, Li+ level must be regularly monitored to maintain therapeutical effect and avoid adverse side effects. Currently, it is determined in blood, using complex instrumentation, which excludes self-monitoring of lithium concentration by patients themselves. That creates a need for simple, reliable and fast sensors for Li monitoring in biological fluids. In this paper, we introduced a microfluidic thread-based analytical device for optical determination of lithium in saliva. Lithium ion recognition was achieved by incorporating of chromoionophore- ionophore chemistry onto thread. To ensure appropriate selectivity over other alkaline metal ions, it was necessary to include an efficient lithium extractant in the sensing cocktail, alongside its usual components. After optimization of cocktail composition, the developed sensors allowed for lithium determination in a range from 8.8⋅10−4 to 0.95 mol L−1 with remarkable precision of 0.3% (at 10−2 mol L−1) and within a very short time of ca. 10 s. The analytical usefulness of the developed sensors was tested with saliva samples, which were analyzed without any prior processing. A comparison of the obtained results with a reference method revealed high ac- curacy (relative error < ±20% in most cases).
Capillary microfluidic platform for sulfite determination in wines
https://hdl.handle.net/10481/72934
Capillary microfluidic platform for sulfite determination in wines
Arroyo, Manuel J.; Orbe Payá, Ignacio De; Ortega Muñoz, Mariano; Vilar Tenorio, Jose; Gallego, David; Mohr, Gerhard J; Capitán Vallvey, Luis Fermín; Erenas Rodríguez, Miguel María
A microfluidic paper-based analytical device integrating a chromoreactand – a formylazo dye– has been fabri- cated and used for a colorimetric assay of sulfites. The chromoreactand was covalently linked to paper by vinyl sulfone chemistry. This work presents two robust capillary microfluidic devices to determine sulfite in wine without any pretreatment. One of them based on thread (µTPAD) useful to determine it in white wine and another based on paper (µPAD) to specifically determine sulfite in red wine as well as in white wine. Both are based on the selective recognition of sulfite by means of a chromoreactand that turns from orange to yellow in the presence of sulfite. The colour information acquired (H coordinate) using a digital camera readout allows for a range of appli-
cation of the µTPAD from 7.8⋅10−5 M (8.1 mg L−1) to 2.7⋅10−3 M (279.3 mg L−1) with a limit of detection (LOD) of 78 µM. The strong interference caused by the dyes present in red wine is eliminated by including a laminated paper
channel in the µPAD structure that allows for the separation of colorants from red wine before the recognition of the sulfite. This makes it possible to adjust the µPAD procedure to the usual sulfite concentration in wine, with an LOD of 2.2⋅10−4 M (22.7 mg L−1) and a CV of 2.6%.
Bioactive microfluidic paper device for pesticide determination in waters
https://hdl.handle.net/10481/62818
Bioactive microfluidic paper device for pesticide determination in waters
Fernández Ramos, María Dolores; Ogunneye, A. L.; Barbarinde, N. A. A.; Erenas Rodríguez, Miguel María; Capitán Vallvey, Luis Fermín
This work presents a new optical microfluidic paper biosensor for the detection of organophosphate pesticides and carbamate pesticides. The assay strip is composed of a paper support (1 × 17.6 mm) onto which acet- ylcholine esterase (AChE) and acetylcholine chloride (AChCl) are deposited, in such a way that there is a small hole between them that ensures that they only come into contact in the reaction zone when they are carried by a solution of the sample by lateral flow to the reaction zone containing bromocresol purple (BCP) as the pH indicator, immobilized by sol-gel. The sensor operates at room temperature and the rate of the inhibited reaction serves as an analytical signal, which is measured using a camera by quantifying the appropriate colour co- ordinate. Calibration curves were obtained for chlorpyrifos and carbaryl, with a useful concentration range from 0.24 to 20 μg L−1 for carbaryl and from 2.00 to 45 μg L−1 for chlorpyrifos. The detection limits were 0.24 and 2.00 μg L−1, respectively, and with reproducibility around 4.2–5.5%. The method was applied to the de- termination of pesticides in different water samples, with no sample preparation.
Chitosan-modified cotton thread for the preconcentration and colorimetric trace determination of Co(II)
https://hdl.handle.net/10481/62815
Chitosan-modified cotton thread for the preconcentration and colorimetric trace determination of Co(II)
Suarez, Willian Toito; Franco, Methewa O.K.; Capitán Vallvey, Luis Fermín; Erenas Rodríguez, Miguel María
In this work we propose a thread-based microfluidic device (μTAD) for the preconcentration and colorimetric determination of Co(II) in water using a digital image. The reaction is based on complexation of Co(II) by 4-(2- pyridylazo) resorcinol (PAR), which changes the detection zone from yellow to red. PAR is immobilized in a chitosan membrane to retain the complex in the detection zone. The designed μTAD makes it possible to pre- concentrate and determine cobalt between 25 and 600 µg·L−1 with a relative standard deviation of 4% (n = 5), and a detection limit of 6.5 µg·L−1. The device permits an enhancement factor of 11 by combining the use of a chitosan retention membrane and a sample volume of 50 µL. Recovery experiments were performed in tap water to evaluate the accuracy of the method, and the results obtained compared to a reference method presents an error no higher than 5.7%
Smartphone-Based Diagnosis of Parasitic Infections With Colorimetric Assays in Centrifuge Tubes
https://hdl.handle.net/10481/59642
Smartphone-Based Diagnosis of Parasitic Infections With Colorimetric Assays in Centrifuge Tubes
Escobedo Araque, Pablo; Erenas Rodríguez, Miguel María; Martínez Olmos, Antonio; Carvajal Rodríguez, Miguel Ángel; Tabraue Chávez, Mavys; Luque González, Angélica; Díaz Mochón, Juan José; Pernagallo, Salvatore; Capitán Vallvey, Luis Fermín; Palma López, Alberto José
A smartphone-based platform for the diagnosis of parasitic infections has been developed,
tested and validated. The system is capable of making automatic and accurate analysis of millimetric
colorimetric arrays in centrifuge collection tubes, which are well established tools used in clinical analysis.
To that end, an Android-based software application has been developed, making use of the smartphone rear
camera, enabling precise image processing of the colorimetric spot arrays. A low-cost plastic accessory
has been developed using 3D-printing to provide controlled illumination, xed sample positioning and cell
phone attachment. The platform was then tested repeatedly for its size detection, edge blurriness and colour
detection capabilities. A minimum spot radius of 175 m is detectable when using the developed app, with a
tolerance of 15%, corresponding to 0.25%of the area where the spot array is printed. Spot edge de nition has
been studied up to 40% of blurriness, resulting in a low average percentage error of 1.24%. Colour detection
follows the well-known Gamma correction function. Finally, the whole platform was tested and validated
using real DNA to analyse for accurate discrimination of Trypanosomatid species, which are responsible
for devastating diseases in humans and livestock. The smartphone-based platform can be further extended to
other clinical analysis. Its simplicity and reliable performance mean it can be used in remote, limited-resource
settings by relatively unskilled technicians/nurses, where diagnostic laboratories are sparsely distributed.
The results can however be sent easily via the smartphone to medical experts as well as government health
agencies.