Selecting DNA aptamers for endotoxin separation.

Objectives: To select aptamers for endotoxin separation from a 75-nucleotide single-stranded DNA random library using systematic evolution of ligands by exponential enrichment.

Results: After 15 rounds of selection, the final pool of aptamers was specific to endotoxin. Structural analysis of aptamers that appeared more than once suggested that one aptamer can form a G-quartet structure. Tests for binding affinity and specificity showed that this aptamer exhibited a high affinity for endotoxin. Using this aptamer, aptamer-magnetic beads were designed to separate endotoxin.

Conclusions: Using these aptamer-magnetic beads, a new method to separate endotoxin was developed to enable specific separation of endotoxin that can be applied to drug and food products.