New trends in the development of electrochemical biosensors for the quantification of microRNAs

MicroRNAs (miRNAs) are non-coding regulatory RNAs that play an important role in RNA silencing and post-transcriptional gene expression regulation. Since their dysregulation has been associated with Alzheimer disease, cardiovascular diseases and different types of cancer, among others, miRNAs can be used as biomarkers for early diagnosis and prognosis of these diseases. The methods commonly used to quantify miRNAs are, in general, complex, costly, with limited application for point-of-care devices or resource-limited facilities. Electrochemical biosensors, mainly those based on nanomaterials, have emerged as a promising alternative to the conventional miRNA detection methods and have paved the way to the development of sensitive, fast, and low-cost detection systems. This review is focused on the most relevant contributions performed in the field of electrochemical miRNAs biosensors between 2017 and the beginning of 2020. The main contribution of this article is the critical discussion of the different amplification strategies and the comparative analysis between amplified and non-amplified miRNA electrochemical biosensing and between the different amplification schemes. Particular emphasis was given to the importance of the nanostructures, enzymes, labelling molecules, and special sequences of nucleic acids or analogues on the organization of the different bioanalytical platforms, the transduction of the hybridization event and the generation the analytical signal.Fil: López Mujica, Michael Earvin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Gallay, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Perrachione, Fabrizio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Montemerlo, Antonella Evelin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Tamborelli, Luis Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Vaschetti, Virginia María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Reartes, Daiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Bollo, Soledad. Facultad de Ciencias Químicas y Farmacéuticas; ChileFil: Rodríguez, Marcela C.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Dalmasso, Pablo Roberto. Universidad Tecnologica Nacional. Facultad Regional Cordoba. Departamento de Ingenieria Quimica. Centro de Investigacion y Transferencia En Ingenieria Quimica.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rubianes, María Dolores. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Rivas, Gustavo Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentin

Advanced Electrochemical and Opto-Electrochemical Biosensors for Quantitative Analysis of Disease Markers and Viruses

The recent global events of the SARS-CoV-2 pandemic in 2020 have alerted the world to the urgent need to develop fast, sensitive, simple, and inexpensive analytical tools that are capable of carrying out a large number of quantitative analyses, not only in centralized laboratories and core facilities but also on site and for point-of-care applications. In particular, in the case of immunological tests, the required sensitivity and specificity is often lacking when carrying out large-scale screening using decentralized methods, while a centralized laboratory with qualified personnel is required for providing quantitative and reliable responses. The advantages typical of electrochemical and optical biosensors (low cost and easy transduction) can nowadays be complemented in terms of improved sensitivity by combining electrochemistry (EC) with optical techniques such as electrochemiluminescence (ECL), EC/surface-enhanced Raman spectroscopy (SERS), and EC/surface plasmon resonance (SPR). This Special Issue addresses existing knowledge gaps and aids in exploring new approaches, solutions, and applications for opto-electrochemical biosensors in the quantitative detection of disease markers, such as cancer biomarkers proteins and allergens, and pathogenic agents such as viruses. Included are seven peer-reviewed papers that cover a range of subjects and applications related to the strategies developed for early diagnosis

Electrochemical affinity biosensors for fast detection of gene-specific methylations with no need for bisulfite and amplification treatments

This paper describes two different electrochemical affinity biosensing approaches for the simple, fast and bisulfite and PCR-free quantification of 5-methylated cytosines (5-mC) in DNA using the anti-5-mC antibody as biorecognition element. One of the biosensing approaches used the anti-5-mC as capture bioreceptor and a sandwich type immunoassay, while the other one involved the use of a specific DNA probe and the anti-5-mC as a detector bioreceptor of the captured methylated DNA. Both strategies, named for simplicity in the text as immunosensor and DNA sensor, respectively, were implemented on the surface of magnetic microparticles and the transduction was accomplished by amperometry at screen-printed carbon electrodes by means of the hydrogen peroxide/hydroquinone system. The resulting amperometric biosensors demonstrated reproducibility throughout the entire protocol, sensitive determination with no need for using amplification strategies, and competitiveness with the conventional enzyme-linked immunosorbent assay methodology and the few electrochemical biosensors reported so far in terms of simplicity, sensitivity and assay time. The DNA sensor exhibited higher sensitivity and allowed the detection of the gene-specific methylations conversely to the immunosensor, which detected global DNA methylation. In addition, the DNA sensor demonstrated successful applicability for 1 h-analysis of specific methylation in two relevant tumor suppressor genes in spiked biological fluids and in genomic DNA extracted from human glioblastoma cells.The financial support of the Spanish Ministerio de Economía y Competitividad CTQ2015-64402-C2-1-R and SAF2014-53209-R Research Projects, the PI17CIII/00045 research project from AESI and the NANOAVANSENS Program from the Comunidad de Madrid (S2013/MT-3029) and predoctoral contracts from the Spanish Ministerio de Economía y Competitividad (R.M. Torrente-Rodríguez and E. Povedano) and Universidad Complutense de Madrid (V. Ruiz-Valdepeñas Montiel) are also gratefully acknowledged.S

Non-Invasive Breast Cancer Diagnosis through Electrochemical Biosensing at Different Molecular Levels

The rapid and accurate determination of specific circulating biomarkers at different molecular levels with non- or minimally invasive methods constitutes a major challenge to improve the breast cancer outcomes and life quality of patients. In this field, electrochemical biosensors have demonstrated to be promising alternatives against more complex conventional strategies to perform fast, accurate and on-site determination of circulating biomarkers at low concentrations in minimally treated body fluids. In this article, after discussing briefly the relevance and current challenges associated with the determination of breast cancer circulating biomarkers, an updated overview of the electrochemical affinity biosensing strategies emerged in the last 5 years for this purpose is provided highlighting the great potentiality of these methodologies. After critically discussing the most interesting features of the electrochemical strategies reported so far for the single or multiplexed determination of such biomarkers with demonstrated applicability in liquid biopsy analysis, existing challenges still to be addressed and future directions in this field will be pointed out

Electrochemical and surface plasmon bioassays for circulating biomarkers

To address analytical detection needs, sensitive and selective assay methodologies are of great importance. Compared to simple buffer medium, a great challenge exists in detecting ultra-low levels of biomarkers in clinical matrices due to their inherent complexity and interferences posed by non-specific molecules. In addition, small molecules do not yield measurable assay signal changes compared to large biomolecules. My thesis research is focused on designing nano-biological interfaces to detect small and large molecules at low parts-per-billion and femto/picomolar concentrations in complex biofluids (serum and urine samples). Compared to harsh and tedious chemical carboxylation, non-covalent carboxylation of multiwalled carbon nanotubes by π-π stacking 1-pyrenebutyric acid retains the innate sp2 structure and electronic properties of the nanotubes and offers surface carboxyl groups for stable covalent amine coupling of a large amount of enzymes, thus improving the sensitivity of the assay. Chapter 2 demonstrates the first pyrenyl carbon nanostructure modified enzymatic bioelectrode for amperometric detection of urine formaldehyde at clinically relevant parts-per-billion levels with selectivity and wide dynamic range. Subsequently, we explored the low dielectric permittivity and intrinsic plasmonics of graphene for the detection of serum glutamic acid decarboxylase autoantibody (GADA). Graphene-based electrochemical immunosensing approach is advantageous due to its additional applicability for surface plasmon based validation and binding strength analysis with surface immobilized GAD-65 antigens (Chapter 3). My thesis focused on the third class of biomarkers, microRNAs, which are small oligonucleotides with 21-25 bases. To develop the microRNA assay with quantitative characterization, surface plasmon resonance imaging (SPRi) coupled with quartz crystal microbalance (QCM) was designed (Chapter 4). Gold nanoparticles (Au NPs) were linked to the oligonucleotides to increase the detection sensitivity upon hybridization with the selective capture oligonucleotide immobilized on the sensor surface with minimal non-specific signals. Often, cancer and other similar health disorders have been shown to be related to various types of biomarkers. Hence, in Chapter 5, we designed a multiplex assay platform for combined measurement of proteins and microRNAs. For this multiplex assay, we synthesized iron-gold bimetallic core/shell nanoparticles (Fe3O4@Au NPs) that displayed a greater plasmonic signal amplification than either Fe3O4 or Au NPs.Chemistr

Novel Electrochemical Biosensors for Clinical Assays

Biosensors, i.e., devices where biological molecules or bio(mimetic)structures are intimately coupled to a chemo/physical transducer for converting a biorecognition event into a measurable signal, have recently gained a wide (if not huge) academic and practical interest for the multitude of their applications in analysis, especially in the field of bioanalysis, medical diagnostics, and clinical assays. Indeed, thanks to their very simple use (permitting sometimes their application at home), the minimal sample pretreatment requirement, the higher selectivity, and sensitivity, biosensors are an essential tool in the detection and monitoring of a wide range of medical conditions from glycemia to Alzheimer’s disease as well as in the monitoring of drug responses. Soon, we expect that their importance and use in clinical diagnostics will expand rapidly so as to be of critical importance to public health in the coming years. This Special Issue would like to focus on recent research and development in the field of biosensors as analytical tools for clinical assays and medical diagnostics