THIOAPTAMER TECHNOLOGY is based on DNA phosphorodithioate (PS2) oligonucleotides and a patented bead-based discovery process that simultaneously selects the DNA sequence and chemical modifications of the DNA-based binding agent. In many instances, only one pass through the selection process is required to find a nuclease-resistant binding agent with high specificity and excellent affinity. However, repeating the selection process with a library specifically designed using results from the first selection may prove beneficial in some instances. Binding agents that use the phosphorodithioate backbone substitution (thioaptamers) have been shown to have enhanced binding affinity up to 600 times over non-PS2 aptamers while retaining excellent specificity.

What are Thioaptamers?
Thioaptamers are extremely stable, chemically-synthesized, DNA oligos that bind with very high specificity and affinity to a wide range of clinically-important biomolecular targets, including proteins, peptides, carbohydrates and small molecules. Thioaptamers are unique and proprietary as a result of the chemical substitution of the non-bridging oxygen phosphodiester linkages with sulfur creating an achiral linkage and as a result of the patent bead-based selection process used to develop them.

Thioaptamer Characteristics
Thioaptamers are extremely stable, chemically synthesized, DNA oligos that can be designed with very high specificity and affinity to a wide range of important
biomolecular targets.

• Very high affinity for target proteins (picomolar to nanomolar)
• Very high specificity
• Nuclease resistant
• PS2 substitution eliminates monothioate backbone stereoisomers
• Indefinite shelf-life – stable against denaturation (unlike antibodies)
• Inexpensive to produce synthetically
• Highly reproducible synthesis – excellent quality control
• Chemical modifications and sequence are selected simultaneously

Producing and Using Thioaptamers
Thiophosphoramidite reagents are used in conjunction with standard sulfurization reagents to create phosphorodithioate oligos on commercially available DNA/RNA synthesizers using modified synthesis protocols.