R NA ) ▁or ▁pl as mid ▁DNA ▁into ▁in ▁vit ro ▁cell ▁cult ures ▁by ▁lip of ection . ▁Lip of ect am ine ▁contains ▁li pid ▁sub un its ▁that ▁can ▁form ▁li pos om es ▁in ▁an ▁a que ous ▁environment , ▁which ▁ent rap ▁the ▁trans fection ▁payload , ▁e . g . ▁DNA ▁pl asm ids . ▁▁ ▁Lip of ect am ine ▁consists ▁of ▁a ▁c ation ic ▁li pos ome ▁form ulation , ▁which ▁complex es ▁with ▁neg atively ▁charged ▁nucle ic ▁acid ▁mole cules ▁to ▁allow ▁them ▁to ▁overcome ▁the ▁electro static ▁rep ulsion ▁of ▁the ▁cell ▁memb rane . ▁Lip of ect am ine ' s ▁c ation ic ▁li pid ▁mole cules ▁are ▁form ulated ▁with ▁a ▁neutral ▁co - lip id ▁( helper ▁li pid ). ▁The ▁DNA - cont aining ▁li pos om es ▁( pos it ively ▁charged ▁on ▁their ▁surface ) ▁can ▁f use ▁with ▁the ▁neg atively ▁charged ▁pl asma ▁memb rane ▁of ▁living ▁cells , ▁due ▁to ▁the ▁neutral ▁co - lip id ▁medi ating ▁fusion ▁of ▁the ▁li pos ome ▁with ▁the ▁cell ▁memb rane , ▁allowing ▁nucle ic ▁acid ▁cargo ▁mole cules ▁to ▁cross ▁into ▁the ▁cy top las m ▁for ▁rep lication ▁or ▁expression . ▁ ▁In ▁order ▁for ▁a ▁cell ▁to ▁express ▁a ▁trans g ene , ▁the ▁nucle ic ▁acid ▁must ▁reach ▁the ▁nucle us ▁of ▁the ▁cell ▁to ▁begin ▁trans cription . ▁However , ▁the ▁trans fect ed ▁gen etic ▁material