Modifications at either end, both ends, or in-between the ends of a Morpholino oligo provide functional groups for further conjugation. Amino groups are the most useful and efficient reactive entities for chemical bonding with other molecules. The combination of modifications at both ends, especially with double functionalization at the 3'-end, yields myriad opportunities for diverse applications. An orthogonally protected diamine for advanced 3'-end double modification on the solid phase synthesis support allows the convenient assembly of a vast variety of custom-designed molecules. A particular application is the assembly of a class of Vis-Vivo-Morpholino where at the 3'-end an optically visible fluorophore is installed at one side for fluorescent detection and an in vivo delivery moiety is attached at the other side for intracellular activity studies.
Keywords: Amino groups; Conjugation; End-modification; Functionalization; Morpholino oligo; Vis-Vivo-Morpholino.