sentence: Such RNA aptamers were shown to have an inhibitor efficiency ( IC50 ) of 5 μ M and could block the binding of Protective Antigen ( PA ) to its receptors in order to neutralize anthrax toxin.Aptamers have also been used for non infections conditions such as hormonal imbalance , intestinal motility , modifying apatite or thirst etc. Becskei et al. ( 2008 ) showed that NOX-B11-3 , a RNA aptamer ( called RNA Spiegelmers ) can suppress appetite during food deprivation by specifically binding to orexigenic hormone ghrelin and blocking its activity .