Staff directory Lourdes Rivas Torcates

Lourdes Rivas Torcates

Postdoctoral Researcher
Nanobioelectronics and Biosensors



  • Nanoparticle-based lateral flow assays

    Calucho E., Parolo C., Rivas L., Álvarez-Diduk R., Merkoçi A. Comprehensive Analytical Chemistry; 2020. 10.1016/bs.coac.2020.04.011. IF: 0.000

    Lateral flow assays (LFAs) are paper-based analytical devices that allow for the performance of in situ diagnostic tests with good sensitivity, specificity, repeatability and low limit of detection. The application of different kinds of nanoparticles with different properties have made LFAs compatible with different detection methods (e.g. colorimetry, photoluminescence, magnetism, heating, electroactivity), thus showing their versatility. Even though LFA technology is well-established, research on the topic is more alive than ever due to the advances in the study of nanomaterials, the implementation of smartphone technology for signal readout and the creativity in finding new strategies for signal enhancement. In this chapter, the applications of LFAs using different kind of nanoparticles as labels are compiled, demonstrating their use in a range of fields such as clinical diagnostics, environmental monitoring, food safety and veterinary. Given the relevance of nanoparticles in the performance of LFAs, a section of the chapter is dedicated to biofunctionalisation strategies. © 2020 Elsevier B.V.


  • Electrochemically reduced graphene and iridium oxide nanoparticles for inhibition-based angiotensin-converting enzyme inhibitor detection

    Kurbanoglu S., Rivas L., Ozkan S.A., Merkoçi A. Biosensors and Bioelectronics; 88: 122 - 129. 2017. 10.1016/j.bios.2016.07.109. IF: 7.780

    In this work, a novel biosensor based on electrochemically reduced graphene oxide and iridium oxide nanoparticles for the detection of angiotensin-converting enzyme inhibitor drug, captopril, is presented. For the preparation of the biosensor, tyrosinase is immobilized onto screen printed electrode by using 1-Ethyl-3-(3-dimethylaminopropyl)-carbodiimide and N-Hydroxysuccinimide coupling reagents, in electrochemically reduced graphene oxide and iridium oxide nanoparticles matrix. Biosensor response is characterized towards catechol, in terms of graphene oxide concentration, number of cycles to reduce graphene oxide, volume of iridium oxide nanoparticles and tyrosinase solution. The designed biosensor is used to inhibit tyrosinase activity by Captopril, which is generally used to treat congestive heart failure. It is an angiotensin-converting enzyme inhibitor that operates via chelating copper at the active site of tyrosinase and thioquinone formation. The captopril detections using both inhibition ways are very sensitive with low limits of detection: 0.019 µM and 0.008 µM for chelating copper at the active site of tyrosinase and thioquinone formation, respectively. The proposed methods have been successfully applied in captopril determination in spiked human serum and pharmaceutical dosage forms with acceptable recovery values. © 2016 Elsevier B.V.


  • An iridium oxide nanoparticle and polythionine thin film based platform for sensitive Leishmania DNA detection

    Mayorga-Martinez C.C., Chamorro-García A., Serrano L., Rivas L., Quesada-Gonzalez D., Altet L., Francino O., Sánchez A., Merkoçi A. Journal of Materials Chemistry B; 3 (26): 5166 - 5171. 2015. 10.1039/c5tb00545k. IF: 4.726

    An impedimetric label-free genosensor for high sensitive DNA detection is developed. This system is based on a screen-printed carbon electrode modified with the thionine layer and iridium oxide nanoparticles (IrO2 NP). An aminated oligonucleotide probe is immobilized on the IrO2 NP/polythionine modified electrode and ethanolamine was used as a blocking agent. Different diluted PCR amplified DNA samples have been detected. The selectivity and reproducibility of this system are studied and the system was highly reproducible with RSD ≈ 15% and sensitive enough while using 2% of ethanolamine during the blocking step employed for genosensor preparation. © The Royal Society of Chemistry.

  • Antithyroid drug detection using an enzyme cascade blocking in a nanoparticle-based lab-on-a-chip system

    Kurbanoglu S., Mayorga-Martinez C.C., Medina-Sánchez M., Rivas L., Ozkan S.A., Merkoçi A. Biosensors and Bioelectronics; 67: 670 - 676. 2015. 10.1016/j.bios.2014.10.014. IF: 6.409

    A methimazole (MT) biosensor based on a nanocomposite of magnetic nanoparticles (MNPs) functionalized with iridium oxide nanoparticles (IrOx NPs) and tyrosinase (Tyr) immobilized onto screen printed electrode (SPE) by using a permanent magnet is presented. This system is evaluated in batch mode via chelating copper at the active site of tyrosinase and in flow mode by thioquinone formation. The MT detection in flow mode is achieved using a hybrid polydimethylsiloxane/polyester amperometric lab-on-a-chip (LOC) microsystem with an integrated SPE. Both systems are very sensitive with low limit of detection (LOD): 0.006. μM and 0.004. μM for batch and flow modes, respectively. Nevertheless, the flow mode has advantages such as its reusability, automation, low sample volume (6. μL), and fast response (20. s). Optimization and validation parameters such as enzyme-substrate amount, flow rate, inhibition conditions, repeatability and reproducibility of the biosensor have been performed. The proposed methods have been applied in MT detection in spiked human serum and pharmaceutical dosage forms. © 2014 Elsevier B.V.

  • Label-free impedimetric aptasensor for ochratoxin-A detection using iridium oxide nanoparticles

    Rivas L., Mayorga-Martinez C.C., Quesada-González D., Zamora-Gálvez A., De La Escosura-Muñiz A., Merkoçi A. Analytical Chemistry; 87 (10): 5167 - 5172. 2015. 10.1021/acs.analchem.5b00890. IF: 5.636

    In this article, a novel aptasensor for ochratoxin A (OTA) detection based on a screen-printed carbon electrode (SPCE) modified with polythionine (PTH) and iridium oxide nanoparticles (IrO2 NPs) is presented. The electrotransducer surface is modified with an electropolymerized film of PTH followed by the assembly of IrO2 NPs on which the aminated aptamer selective to OTA is exchanged with the citrate ions surrounding IrO2 NPs via electrostatic interactions with the same surface. Electrochemical impedance spectroscopy (EIS) in the presence of the [Fe(CN)6]-3/-4 redox probe is employed to characterize each step in the aptasensor assay and also for label-free detection of OTA in a range between 0.01 and 100 nM, obtaining one of the lowest limits of detection reported so far for label-free impedimetric detection of OTA (14 pM; 5.65 ng/kg). The reported system also exhibits a high reproducibility, a good performance with a white wine sample, and an excellent specificity against another toxin present in such sample. © 2015 American Chemical Society.

  • Triple lines gold nanoparticle-based lateral flow assay for enhanced and simultaneous detection of Leishmania DNA and endogenous control

    Rivas L., de la Escosura-Muñiz A., Serrano L., Altet L., Francino O., Sánchez A., Merkoçi A. Nano Research; 8 (11): 3704 - 3714. 2015. 10.1007/s12274-015-0870-3. IF: 7.010

    A novel triple lines lateral-flow assay (LFA) with enhanced sensitivity for the detection of Leishmania infantum DNA in dog blood samples was designed and successfully applied. The enhanced LFA methodology takes advantage of the gold nanoparticle tags (AuNPs) conjugated to polyclonal secondary antibodies, which recognize anti-FITC antibodies. The polyclonal nature of the secondary antibodies allows for multiple binding to primary antibodies, leading to enhanced AuNP plasmonics signal. Furthermore, endogenous control consisting of the amplified dog 18S rRNA gene was introduced to avoid false negatives. Using this strategy, 0.038 spiked Leishmania parasites per DNA amplification reaction (1 parasite/100 μL of DNA sample) were detected. Detection limit of LFA was found to be lower than that of the conventional techniques. In summary, our novel LFA design is a universal and simple sensing alternative that can be extended to several other biosensing scenarios. [Figure not available: see fulltext.] © 2015, Tsinghua University Press and Springer-Verlag Berlin Heidelberg.


  • Electrochemical antibody-aptamer assay for VEGF cancer biomarker detection

    Ravalli A.; Marrazza G.; Rivas L.; De La Escosura-Muniz A.; Merkoci A. Lecture Notes in Electrical Engineering; 268 LNEE: 175 - 178. 2014. . IF: 0.000