Architecture of high-affinity unnatural-base DNA aptamers toward pharmaceutical applications.

We present a remodeling method for high-affinity unnatural-base DNA aptamers to augment their thermal stability and nuclease resistance, for use as drug candidates targeting specific proteins. Introducing a unique mini-hairpin DNA provides robust stability to unnatural-base DNA aptamers generated by SELEX using genetic alphabet expansion, without reducing their high affinity. By this method, >80% of the remodeled DNA aptamer targeting interferon-γ (KD of 33 pM) survived in human serum at 37 °C after 3 days under our experimental conditions, and sustainably inhibited the biological activity of interferon-γ.