Biosensors based on molecular beacons

Abstract

A fundamental molecular beacon (MB) consists of a special short nucleic acid strand with a fluorophore-quencher pair attached to its ends. It provides a unique framework that is susceptible to conformational transitions between a hairpin (closed) conformation and an extended (open) conformation. These two conformations are readily discernible because of their differing fluorescence emission characteristics. The broad applicability of the robust MB sensing platform has attracted widespread interest, resulting in extensive research studies ranging from theoretical and bioanalytical chemistry to molecular biology and biomedical applications. In this paper, the principles of MB design and the modes and mechanisms of MB operation are reviewed, including MB modifications based on the utilisation of a thymidine-thymidine mismatch in hybridised MB stem, aptamers, peptides and locked nucleic acid strands in an MB loop, as well as plasmonic quenchers, quantum dots and interactions with graphene and graphene oxide. Specific applications of MBs in the analysis of enzymes, DNA mutation, phosphorylation, methylation and ligation, followed by the detection of pathogens and applications in cancer and other disease diagnostics and therapeutics are also reviewed. Molecular beacon-based sensing platforms are expanding rapidly and offer a promising bioanalytical tool for inexpensive and reliable analysis for research and field diagnostics.

Universal Fluorescence Biosensor Platform Based on Graphene Quantum Dots and Pyrene-Functionalized Molecular Beacons for Detection of MicroRNAs

“…3,4 MBs had explored wide applications in molecular biological studies, pathogen detection, and biomedical diagnostics. 5,6 Graphene quantum dots (GQDs) are nanometer-sized graphene fragments, where electronic transport is confined in all three spatial dimensions. 7,8 Because of the unique properties, GQDs have attracted great attentions in a wide range of new applications.…”

Electrochemical Methods for Probing DNA Damage Mechanisms and Designing Cisplatin-Based Combination Chemotherapy

“…Conventional methods include: gel electrophoresis [14], restriction enzyme assay [22,23], high-performance GC/MS [24] and ELISA [25]. In addition, fluorescent oligonucleotide molecular beacons were used for detection of single base polymorphism [26]. The surface-enhanced Raman scattering (SERS)-electrochemical method and the nanogrid DNA sensor were developed specifically to monitor DNA damage caused by chemotherapeutic drugs [27,28].…”

Dual‐Hemin‐Labelled Catalytic Molecular Beacon: A Monomer‐Dimer Switching Probe for Sensitive Chemiluminescence Detection of Biomolecules

“…MB‐based detection system is separation‐free and very simple. Thus, since the first report by Tyagi and Kramer in 1996, MB has become a very popular probe for nucleic acid analysis and triggered a cascade of related developments in the field of molecular sensing . Though MB is one powerful probe with highly specificity, there remain some challenging problems.…”