MicroRNAs in ovarian cancer and recent advances in the development of microRNA-based biosensors

Ovarian cancer is the most aggressive of all gynaecological malignancies and is the leading cause of cancer-associated mortality worldwide. Over the recent years, there has been a sharp increase in this mortality rate, mostly due to late diagnosis, which can be attributed to the lack of an early and specific biomarker. Under this scenario, recent interest has shifted towards ovarian cancer associated miRNAs which play strong regulatory roles in various cellular processes. miRNAs have emerged as promising non/minimally invasive cancer biomarkers for improved diagnostic, prognostic and streamlined therapeutic applications. A large number of miRNA assays have been reported that are based on nucleic acid detection-based techniques such as RT-qPCR, microarrays and RNA sequencing methods. Despite demonstrating commendable analytical performances, these laboratory-based techniques are expensive and hence not ideally suited for routine use in resource-limited settings. In recent years, considerable attention has been dedicated to the development of relatively simple, rapid and inexpensive miRNA biosensor strategies. Among these, electrochemical sensors have shown a great promise towards point-of-care diagnostics, due to their inherent advantages such as simplicity, sensitivity, amenability to high levels of multiplexing as well as low cost. In this paper, we provide an overview of the potential role of miRNAs in ovarian cancer, as well as recent advances in the development of nanotechnology-based, optical, and electrochemical biosensing-strategies for miRNA detection

Sensitive Detection of Motor Neuron Disease Derived Exosomal miRNA Using Electrocatalytic Activity of Gold-Loaded Superparamagnetic Ferric Oxide Nanocubes

© 2020 Wiley-VCH GmbH Dysregulated microRNA associated pathways contribute to the pathology of neurological disorders, hence presenting themselves as a potential candidate for motor neuron disease (MND) diagnosis. Herein, we reported an enzymatic amplification-free approach for the electrochemical detection of exosomal microRNA (miR-338-3p) from preconditioned media of motor neurons obtained from amyotrophic lateral sclerosis (ALS) patients and healthy controls. Our assay utilizes a three-step strategy that involves i) initial isolation and purification of exosomal miR-338-3p from patients and healthy controls using biotinylated complementary capture probe followed by heat-release of the specific target, ii) direct adsorption of target miR-338-3p onto the gold-loaded ferric oxide nanocatalyst (AuNP-Fe2O3NC) through affinity interaction between microRNA and exposed gold surfaces within the AuNP-Fe2O3NC, and iii) gold nanocatalyst-induced electrocatalytic signal amplification through methylene blue-ferricyanide redox cycling (MB/[Fe(CN)6]3−). The electrocatalytic signal is monitored by using chronocoulometry at the AuNP–Fe2O3NC-modified screen-printed carbon electrode (AuNP-Fe2O3NC/SPCE). We demonstrated the detection of miR-338-3p as low as 100 aM in spiked buffer samples with a relative standard deviation of (%RSD) \u3c5.0 % (n=5). We also demonstrate the successful detection of miR-338-3p from a small cohort of preconditioned media of motor neurons obtained from ALS patients and healthy controls. The sensor avoids the use of conventional recognition and transduction layers in hybridization-based electrochemical miRNA biosensors, polymerase-based amplifications. It is robust, fast (\u3c2.5 h) and potentially applicable to a wide variety of RNA biomarker detection

Sensitive detection of Motor Neuron Disease (MND) derived exosomal miRNA using electrocatalytic activity of gold‐loaded superparamagnetic ferric oxide nanocubes

Dysregulated microRNA associated pathways contribute to the pathology of neurological disorders, hence presenting themselves as a potential candidate for motor neuron disease (MND) diagnosis. Herein, we reported an enzymatic amplification‐free approach for the electrochemical detection of exosomal microRNA (miR‐338‐3p) from preconditioned media of motor neurons obtained from amyotrophic lateral sclerosis (ALS) patients and healthy controls. Our assay utilizes a three‐step strategy that involves i) initial isolation and purification of exosomal miR‐338‐3p from patients and healthy controls using biotinylated complementary capture probe followed by heat‐release of the specific target, ii) direct adsorption of target miR‐338‐3p onto the gold‐loaded ferric oxide nanocatalyst (AuNP‐Fe2O3NC) through affinity interaction between microRNA and exposed gold surfaces within the AuNP‐Fe2O3NC, and iii) gold nanocatalyst‐induced electrocatalytic signal amplification through methylene blue‐ferricyanide redox cycling (MB/[Fe(CN)6]3−). The electrocatalytic signal is monitored by using chronocoulometry at the AuNP–Fe2O3NC‐modified screen‐printed carbon electrode (AuNP‐Fe2O3NC/SPCE). We demonstrated the detection of miR‐338‐3p as low as 100 aM in spiked buffer samples with a relative standard deviation of (%RSD