text: The technique has been used to evolve aptamers of extremely high binding affinity to a variety of target ligands, including small molecules such as ATP and adenosine and proteins such as prions and vascular endothelial growth factor (VEGF). Moreover, SELEX has been used to select high-affinity aptamers for complex targets such as tumor cells, tumor exosomes, or tumor tissue. Clinical uses of the technique are suggested by aptamers that bind tumor markers, GFP-related fluorophores, and a VEGF-binding aptamer trade-named Macugen has been approved by the FDA for treatment of macular degeneration. Additionally, SELEX has been utilized to obtain highly specific catalytic DNA or DNAzymes. Several metal-specific DNAzymes have been reported including the GR-5 DNAzyme (lead-specific), the CA1-3 DNAzymes (copper-specific), the 39E DNAzyme (uranyl-specific)  and the NaA43 DNAzyme (sodium-specific).
  These developed aptamers have seen diverse application in therapies for macular degeneration and various research applications including biosensors, fluorescent labeling of proteins and cells, and selective enzyme inhibition.