Although transfection reagents which are usually positively charged vectors expose high gene transfer activity in vitro, systemic administration of such particles is rather restricted. After tail vein injection of different positively charged lipo- and polyplexes into mice, complexes were rapidly cleared from the circulation and mainly accumulated in the lung due to the unspecific binding with extracellular components. 

A cartoon showing shielded GenJet™ Plus transfection reagent for in vivo DNA transfection

To eliminate the unspecific interaction between cationic nonviral vector with blood components in circulation, we utilized GenJet™ Plus reagent as backbone and cross-linked a shielding peptide (SP) with amine group of neutral lipid of the backbone. The initial testing results showed that administration of shielded GenJet™ Plus did not induce erythrocyte aggregation. Instead systematic injection of shielded GenJet™ Plus led to enhanced systematic circulation with significant improvement of renilla luciferase expression in lung, spleen and liver compared with control GenJet™ Plus without shield peptide.