Abstract
Nucleic acid aptamers are short RNA- or DNA-based affinity reagents typically selected from combinatorial libraries to bind to a specific target such as a protein, a small molecule, whole cells or even animals. Aptamers have utility in the development of diagnostic, imaging and therapeutic applications due to their size, physico-chemical nature and ease of synthesis and modification to suit the application. A variety of oligonucleotide modifications have been used to enhance the stability of aptamers from nuclease degradation in vivo. The non-bridging oxygen atoms of the phosphodiester backbones of RNA and DNA aptamers can be substituted with one or two sulfur atoms, resulting in thioaptamers with phosphorothioate or phosphorodithioate linkages, respectively. Such thioaptamers are known to have increased binding affinity towards their target, as well as enhanced resistance to nuclease degradation. In this review, we discuss the development of phosphorothioate chemistry and thioaptamers, with a brief review of selection methods.
Highlights
Nucleic acid aptamers are short segments of single-stranded DNA or RNA that mimic antibodies in their ability to recognize and bind cognate target molecules with high affinities [1,2,3].The aptamer field began in 1990 with the work of three groups
A wide variety of oligonucleotide substitutions are available, and these methods have been exhaustively reviewed in several recent articles [7,8,184,187]
While thioaptamers exhaustively reviewed in several recent articles [7,8,184,187] and older publications [188,189,190]
Summary
Nucleic acid aptamers are short segments of single-stranded DNA or RNA that mimic antibodies in their ability to recognize and bind cognate target molecules with high affinities [1,2,3]. Wang et al, in a method they call Morph-X-Select, incorporated the use of laser-microdissection to enable more precise morphology-based selection of aptamers or thioaptamers directly from pathological tissue slices [14] They were able to simultaneously select aptamers (to unknown targets) and discover new biomarkers from tissue-bearing ovarian cancer, and do so for both the tumor vessels and the tumor cells. Other non-SELEX methods with separations based on chromatography (MonoLEX) [37,38], bead libraries [39], microfluidics (mSELEX) [40,41,42], atomic force microscopy (AFM) [43,44], graphene oxide (GO-SELEX) [45,46,47], surface plasmon resonance (SPR) [48,49,50] or fluorescence-activated cell sorting (FACS) [51,52] can reduce the time requirements and number of selection rounds required to obtain aptamers. The phosphate backbones of aptamers have been stabilized with the introduction of boranophosphates [71] and thio-/dithio-phosphates [72,73,74,75], which are the focus of this review
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
