Aptamer in bioanalytical applications.

Abstract

With over 2,000 publications, including about 250 reviews, resulting from a SciFinder search in just a two year period (2009–2010), the field of aptamer research has continuously generated lots of interest in the scientific community. Aptamers, first reported by three groups independently in 1990,1–3 are the artificial single-stranded DNA or RNA sequences (more recently, peptides) that fold into secondary and tertiary structures making them bind to certain targets with extremely high specificity. Owing to the high specific affinity of an aptamer to its target molecule (small molecules, proteins and even entire cells), it is thought to resemble chemical antibodies, with the dissociation constants ranging from nanomolar to picomolar level. Aptamers have a number of unique features which make them a more effective choice than antibodies. First, aptamers can be screened via in vitro process against a synthetic library, making it possible to target any molecules (from small inorganic ions to intact cells), overcoming the limit of having to use cell lines or animals, as is necessary for antibodies. Second, aptamers, once selected, can undergo subsequent amplification through polymerase chain reaction to produce a large quantity with high purity. Third, the simple chemical structure of aptamer makes it easily amendable to further modifications with functional groups according to different purposes. Finally, aptamers are much more stable than antibodies, making them suitable in applications requiring harsh conditions (e.g., high temperature or extreme pH). The applications of aptamers remain very dynamic, with increasing explorations in the fields of biosensing, diagnostics and therapeutics (some aptamer-based applications are illustrated in Figure 1). There have been a numbers of excellent reviews in recent years with different emphases.4–8 Herein, as the first review of aptamers on Analytical Chemistry, we attempt to cover major progresses in bioanalytical applications of aptamers in the past 2 years. Figure 1 The widespread use of aptamers for numerous analytical and biological applications. Bioanalytical applications of aptamers are highlighted in red.