Aptamers: molecular tools for analytical applications

Abstract

Aptamers are artificial nucleic acid ligands, specifically generated against certain targets, such as amino acids, drugs, proteins or other molecules. In nature they exist as a nucleic acid based genetic regulatory element called a riboswitch. For generation of artificial ligands, they are isolated from combinatorial libraries of synthetic nucleic acid by exponential enrichment, via an in vitro iterative process of adsorption, recovery and reamplification known as systematic evolution of ligands by exponential enrichment (SELEX). Thanks to their unique characteristics and chemical structure, aptamers offer themselves as ideal candidates for use in analytical devices and techniques. Recent progress in the aptamer selection and incorporation of aptamers into molecular beacon structures will ensure the application of aptamers for functional and quantitative proteomics and high-throughput screening for drug discovery, as well as in various analytical applications. The properties of aptamers as well as recent developments in improved, time-efficient methods for their selection and stabilization are outlined. The use of these powerful molecular tools for analysis and the advantages they offer over existing affinity biocomponents are discussed. Finally the evolving use of aptamers in specific analytical applications such as chromatography, ELISA-type assays, biosensors and affinity PCR as well as current avenues of research and future perspectives conclude this review.

Surface modification, functionalization and bioconjugation of colloidal inorganic nanoparticles

“…This interaction is mediated by electrostatic, hydrophobic van der Waals forces or hydrogen bonds. This can be exploited to generate the so-called aptamer sequences to a given target molecule by molecular evolution, technically realized by multiple randomization, selection and amplification of strongly binding sequences, resulting in an optimized strand of DNA, RNA or peptide for the target molecule with affinities comparable to antibodies (Bunka & Stockley 2006;Lu & Liu 2006;Mairal et al 2008). Aptamers have been attached to gold nanoparticles via a thiol function (Liu et al 2007a;Zhao et al 2008), to quantum dots or silica-coated Au particles by covalent conjugation chemistry (Bagalkot et al 2007;Jana & Ying 2008), to avidin-modified magnetic nanoparticles (Herr et al 2006), as well as biotinylated DNA apatamers to quantum dots with streptavidin (Levy et al 2005).…”

Anti-bovine Prion protein RNA aptamer containing tandem GGA repeat interacts both with recombinant bovine prion protein and its β isoform with high affinity

“…Aptamers are artificial nucleotides derived from systematic evolution of ligands by exponential enrichment (SELEX), 6,7 which bind a wide range of targets with a high affinity and specificity, as is seen with antibodies. 8,9 Using this method, many aptamers specific to PrP [10][11][12][13][14][15][16][17][18][19][20] and PrP Sc , 12,13 have been isolated.…”

Optical Biosensing and Bioimaging With Porous Silicon and Silicon Quantum Dots (Invited Review)

“…Lately, aptamers, short single-strand oligonucleotides that have high and specific binding affinity to proteins, have become new bioreceptors for the detection of various analytes [49][50][51][52]. Aptamers have advantages over antibodies in fast, low-cost and controllable synthesis and chemical stability [53][54][55]. Chhasatia et al compared the performance of an antibody-modified porous silicon optical biosensor to an aptamer-porous silicon biosensor in the analysis of insulin in islet production [56].…”