An antibody fragment functionalized dendritic PEGylated poly(2-(dimethylamino)ethyl diacrylate) as a vehicle of exogenous microRNA

The translation of interfering RNA to the clinic requires more effective delivery agents to enable safe and efficient delivery. The aim of this work was to create a multi-functional delivery agent using deactivation enhanced ATRP synthesis of poly(dimethylamino)ethyl methacrylate (pDMAEMA)-co-PEGMEA/PEGDA (pD-_b-P/DA) with linear pDMAEMA as a macro-initiator. The pD-_b-P/DA was characterized for its potential to bind synthetic micro- RNA mimics to form structures and reacted with antibodyderived fragments (Fabs) using Michael-type addition. Conjugation of antibody fragments was verified using SDS- PAGE. Functional delivery of these interfering RNA complexes was proven using a dual luciferase reporter assay. Functional silencing of a reporter gene was improved by complexation of microRNA mimics with pD-_b-P/DA alone and with Fab-decorated pD-_b-P/DA. The improved silencing with Fab-decorated pD-_b-P/DA was evident at 48 h but disappeared at 96 h. The resultant agent enables complexation of nucleic acid (microRNA mimic) and facile conjugation of antibody fragments via a Michael-type addition. In conclusion, this platform is effective at silencing in this reporter system and has potential as an effective delivery system of interfering RNA.