Ricin immobilization

RNA aptamer specifically binding and inhibiting the activity of the catalytic ricin A-chain (RTA) has been selected [57]. Initially 80 nucleotides long, it has been shortened to 31-nucleotide aptamer that contained all sequences and structures necessary for interacting with RTA. Inhibition properties of this aptamer exceeded known ricin inhibitors. This aptamer along with others was used to develop a multispecific sensor. Aptamers were immobilized on beads, introduced into micromachined chips on the electronic tongue sensor array, and used for the detection and quantification of proteins. The lowest detected ricin concentration using this sensor was 1 pM (320 ng/mL) [58]. 

Ricin, the toxin of Ricinus communis, has been adsorbed on guar gum, a polysaccharide containing D-galactosyl and D-mannosyl residues.The nonbinding toxic A chain is then isolated by reduction of the immobilized toxin with 2-mercaptoethanol, and the B chain is eluted with lactose. A nucleotidebinding domain in the A-chain was demonstrated from its interaction with Cibacron Blue F3GA. 

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