Trends in Biotechnology
ReviewStrand Displacement Strategies for Biosensor Applications
Section snippets
Dynamic Nucleic Acid Hybridization for Strand Displacement
Although nucleic acids primarily function to transfer genetic information between generations of organisms, their physiochemical properties, including stable secondary structure and the dependable encodability of the Watson–Crick base pair, provide a multitude of opportunities for applications in nanotechnology 1, 2, 3, 4. One such application is the thermodynamically driven SDR (Figure 1, Key Figure) [5]. Typically, this reaction involves three elements: a substrate strand, an initiator
Biosensing Applications of SDRs
The dynamic nature, high degree of control, and freedom of the SDR design make this a powerful tool for biomolecule detection and, therefore, for biosensors. One key element of a biosensor is a specific recognition element to preferentially bind to the target analyte. Recognition elements can be antibodies, proteins, DNA or RNA aptamers, or single-stranded nucleic acids. Binding between the recognition element and the analyte is converted to an observable signal by signal transducers. Common
Optical Sensors
Optical sensors function as homogeneous assays, directly performing target analysis in a single container containing the sample specimen. Readout from such assays is based on a change in absorbance or fluorescence due to the binding of the analyte of interest to a recognition element. Therefore, optical readout negates the need for engineering and fabrication of complex sensing devices.
Electrochemical Biosensors
Electrochemical readout is one of the best-established and most reliable technologies for point-of-care sensors, and the electrochemical glucose sensor sets the standard for such devices 59, 60. These biosensors have continued to increase in popularity over the past decade 19, 42, 54, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71. Their continued success can be attributed to the simplicity and low cost of the instrumentation required [66]. However, limitations remain for some types of
Peptide-Based SDRs
Most current SDR technologies rely on nucleic acids. However, nature has provided another class of programmable biopolymers, based on amino acids, which are more functionally diverse than nucleic acids. Developing SDRs with peptides combines the functionality of amino acids with the controllability of the SDR. To date, fairly simple coiled-coil-based peptide SDRs have been demonstrated [87]. Very recently, a biosensing motor based on a peptide displacement reaction for Tau protein detection was
Glossary
- CRISPR/Cas9
- clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein 9 (Cas9) constitute an RNA-guided endonuclease that targets its complementary sequence through recognition of protospacer adjacent motif (PAM) by Cas protein and complementarity confirmation by guide RNA.
- Circulating nucleic acids (CNAs)
- DNA/RNA segments that are released from dying cells into the bloodstream.
- DNA origami
- folding of DNA to construct 2D or 3D shapes through computational
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