Patent ID: 7601872

Claim:
A method for introducing a nucleic acid into a cell, comprising the steps of contacting the nucleic acid with a polycation, thereby forming a complex; and incubating the complex with the cell, wherein the polycation has the formula: where: Q is N; L is [(CH 2 ) i —Y—(CH 2 ) j ] k , where Y is a CH 2 , an ether, an amide, a thiourea, an imine, a carbonyl, or a secondary amino group; R 1 , R 3 , R 4 , and R 6 , independently of one another, are selected from H, alkyl, alkenyl, or alkynyl; R 2 and R 5 , independently of one another, are —(CH 2 ) p -D-Z, wherein (CH 2 ) p is optionally substituted with —OH; D is a bond or Q; Z is an amine, a polyamine or a diaminoalkyl optionally substituted with —OH; X − is a physiologically acceptable anion; a is the number of positive charges divided by the valence of the anion; m and n are 1; r, s, u, and y are 1; i and j are independently an integer from 0 to about 100; k is an integer from 1 to about 100; p is an integer from 1 to about 100; q is an integer from 1 to about 100, and wherein, i) R 1 , R 3 , R 4 , and R 6 are optionally substituted by one or more of an alcohol, an amino alcohol, or an amine; and ii) any two or more of R 1 , R 3 , R 4 and R 6 are covalently linked with each other thereby forming a cyclic moiety.