Adapting Selected Nucleic Acid Ligands (Aptamers) to Biosensors

Abstract

A flexible biosensor has been developed that utilizes immobilized nucleic acid aptamers to specifically detect free nonlabeled non-nucleic acid targets such as proteins. In a model system, an anti-thrombin DNA aptamer was fluorescently labeled and covalently attached to a glass support. Thrombin in solution was selectively detected by following changes in the evanescent-wave-induced fluorescence anisotropy of the immobilized aptamer. The new biosensor can detect as little as 0.7 amol of thrombin in a 140-pL interrogated volume, has a dynamic range of 3 orders of magnitude, has an inter-sensing-element measurement precision of better than 4% RSD over the range 0-200 nM, and requires less than 10 min for sample analysis. The aptamer-sensor format is generalizable and should allow sensitive, selective, and fast determination of a wide range of analytes.

Light-switching excimer probes for rapid protein monitoring in complex biological fluids

“…Aptamers are single-stranded oligonucleotides selected to bind essentially any molecular targets with high selectivity and affinity through an in vitro selection process called SELEX (selective evolution of ligands by exponential enrichment) (4)(5)(6). Besides their excellent binding affinity and selectivity, other characteristics endow aptamers with great potential for use in protein analysis (7,8). For instance, aptamers can be routinely prepared by chemical synthesis, which allows rapid preparation in large quantity and with excellent reproducibility.…”

“…Fluorescent techniques offer excellent choices for signal transduction because of their nondestructive and highly sensitive nature. Several fluorescence techniques such as fluorescence anisotropy (7,8) and fluorescence resonance energy transfer (FRET) (9), as well as fluorescence quenching (9)(10)(11), have been used in aptamer assay development. All these signaltransduction techniques have their individual strengths.…”

Gravimetric Viral Diagnostics: QCM Based Biosensors for Early Detection of Viruses

“…Specifically, the aptamers are composed only of 4 different nucleic acids, while proteins have 20 amino acid building blocks and thousands of monomers are available commercially [158]. As a result there is less chemical flexibility, when using aptamers [159].…”

Aptamer-based therapeutics and their potential in radiopharmaceutical design

“…Aptamers have been selected for various purposes, making use of their high specificity, versatility and affinity in target recognition. Examples include aptamers that recognize proteins, peptides, dyes, amino acids, nucleotides, and drugs among others, to act as biosensors (Potyrailo et al, 1998), probes (Pavski and Le, 2001) and anti-clotting agents (Bock et al, 1992), whilst the first aptamer has made it to the market gaining FDA approval.…”