In Vivo Bone-Targeting of Bis(phosphonate)-Conjugated Double Helical RNA Monitored by Positron Emission Tomography

A bis(phosphonate) conjugate of 2′-O-methyl oligoribonucleotide (microRNA-21) was synthesized and used as a bone-targeting carrier in the systemic delivery of a 68Ga-1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA)-chelated 2′-O-methyl oligoribonucleotide (anti-microRNA-21). The whole-body biodistribution of the double helical RNA was monitored by positron emission tomography (PET), which verified the expected bis(phosphonate)-induced bone accumulation in healthy rats.