X-Aptamer Selection and Validation

  • Ganesh L. Lokesh
  • Hongyu Wang
  • Curtis H. Lam
  • Varatharasa Thiviyanathan
  • Nancy Ward
  • David G. GorensteinEmail author
  • David E. Volk
Part of the Methods in Molecular Biology book series (MIMB, volume 1632)


Aptamers and second generation analogs, such as X-Aptamers (XAs), SOMAmers, locked nucleic acids (LNAs), and others are increasingly being used for molecular pathway targeting, biomarker discovery, or disease diagnosis by interacting with protein targets on the surface of cells or in solution. Such targeting is being used for imaging, diagnostic evaluation, interference of protein function, or delivery of therapeutic agents. Selection of aptamers using the original SELEX method is cumbersome and time-consuming, often requiring 10–15 rounds of selection, and provides aptamers with a limited number of functional groups, namely four bases of DNA or RNA, although newer SELEX methods have increased this diversity. In contrast, X-Aptamers provide an unlimited number of functional groups and thus are superior targeting agents. Here, we discuss the X-Aptamer selection process.

Key words

Aptamer X-Aptamer Molecular targeting Biotin labeling Dye labeling Bead-based selection Split-pool synthesis Drug aptamer conjugation Aptamer nanoparticle conjugation Aptamer siRNA chimeras Chemical cross-linking Proteomics 


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Copyright information

© Springer Science+Business Media LLC 2017

Authors and Affiliations

  • Ganesh L. Lokesh
    • 1
    • 2
  • Hongyu Wang
    • 1
    • 2
  • Curtis H. Lam
    • 3
  • Varatharasa Thiviyanathan
    • 1
    • 2
  • Nancy Ward
    • 3
  • David G. Gorenstein
    • 3
    Email author
  • David E. Volk
    • 1
    • 2
  1. 1.Institute of Molecular Medicine for the Prevention of Human DiseasesThe University of Texas Health Science CenterHoustonUSA
  2. 2.Department of Nanomedicine and Biomedical Engineering, McGovern Medical SchoolThe University of Texas Health Science CenterHoustonUSA
  3. 3.AM Biotechnologies, LLCHoustonUSA

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