Homogeneous assays using aptamers.
Aptamers are DNA or RNA oligonucleotides that can bind with high affinity and specificity to a wide range of targets such as proteins, metal ions or pathogenic microorganisms. Soluble aptamers and aptazymes have been used as sensing elements for developing homogeneous assays in a solution phase, the whole sensing process being carried out in a homogeneous solution. Contrary to most conventional heterogeneous assays that are time-consuming and labor-intensive, aptamer-based homogeneous assays are simple, easy-to-perform, rapid and do not require immobilization nor washing steps. To our knowledge, this review is the first entirely dedicated to aptamer-based homogeneous assays. Optical detection appears as the most developed technique. Colorimetry represents the simplest sensing mode that occupies a very important position among aptamer-based assays, involving gold nanoparticle aggregation (with unmodified or aptamer-modified gold NPs), the formation of HRP-mimicking DNAzyme with hemin, dye displacement or interactions with a cationic polymer. Fluorescence that is highly sensitive offers the most developed detection mode. Aptamers can be labeled or not, to give rise to turn-on or usually less sensitive turn-off fluorescent assays. Newly reported and thus less developed non-conventional magnetic resonance imaging (MRI) and electrochemistry also recently appeared in the literature, thrombin still remains the main detected target. Homogeneous assays based on aptazyme, an aptamer sequence connected to a known ribozyme motif, are also described in this review, involving optical detection, by colorimetry or fluorescence.
Sassolas
Audrey
A
CNRS, UMR 5246, ICBMS, Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, Génie Enzymatique, Membranes Biomimétiques et Assemblages Supramoléculaires (GEMBAS), Université Lyon 1, Bât CPE, 43 boulevard du 11 novembre 1918, Villeurbanne, F-69622, France.
Blum
Loïc J
LJ
Leca-Bouvier
Béatrice D
BD
D000818:Animals; D052157:Aptamers, Nucleotide / Q000737:chemistry / Q000378:metabolism*; D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods*; D003124:Colorimetry / Q000379:methods; D055664:Electrochemical Techniques / Q000379:methods; D005453:Fluorescence; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008969:Molecular Sequence Data; D016337:RNA, Catalytic / Q000378:metabolism
D052157:Aptamers, Nucleotide; D016337:RNA, Catalytic