Methods for promoting entry of an agent into a cell

A method for promoting entry of an agent (introduced agent) into a cell, the method comprising the step of complexing the introduced agent in the presence of an entry-promoting agent and then exposing to cells, wherein the entry-promoting agent comprises a linear and/or branched or cyclic polymonoguanide/polyguanidine, polybiguanide, analogue or derivative thereof according to the following Formula 1a & b. The method also provides a means for formation of nanoparticles formed between the entry promoting agent and the introduced agent. wherein: “n”, refers to number of repeating units in the polymer, and n can vary from 2 to 1000, for example from 2 or 5 to 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800 or 900; G 1 and G 2 independently represent a cationic group comprising biguanide or guanidine, wherein L 1 , and L 2 are directly joined to a Nitrogen atom of the guanide; L 1 and L 2 are linking groups between the G 1 and G 2 cationic groups in the polymer and independently represent an aliphatic group containing C 1 -C 40 carbon atoms, for example an alkyl group such as methylene, ethylene, propylene, C 4 , C 5 , C 6 , C 7 , C 8 , C 9 or C 10 ; C 1 -C 10 , -C 20 , -C 30 , -C 40 , -C 50 -C 60 -C 70 , -C 80 , -C 90 , -C- 100 , -C 110 , -C 120 , -C 130 or -C 140 , alkyl; or a C 1 -C 140 (for example C 1 , C 2 , C 3 , C 4 , C 5 , C 6 , C 7 , C 8 , C 9 or C 10 ; C 1 -C 10 , -C 20 , -C 30 , -C 40 , -C 50 -C 60 , -C 70 , -C 80 , -C 90 , -C 100 , -C 110 , -C 120 , -C 130 or -C 140 ), cycloaliphatic, heterocyclic, aromatic, aryl, alkylaryl, arylalkyl, or oxyalkylene radical; or a polyalkylene radical optionally interrupted by one or more, preferably one, oxygen, nitrogen or sulphur atoms, functional groups or saturated or unsaturated cyclic moiety: N and G 3 are optional end groups; X can be either present or absent; L 3 , L 4 and X are linking groups between the G 4 and G 5 cationic groups in the polymer and independently represent an aliphatic group containing C 1 -C 140 carbon atoms, for example an alkyl group such as methylene, ethylene, propylene, C 4 , C 5 , C 6 , C 7 , C 8 , C 9 or C 10 ; C 1 -C 10 , -C 20 , -C 30 , -C 40 , -C 50 -C 60 , -C 70 , -C 80 , -C 90 , -C 100 , -C 110 , -C 120 , -C 130 or -C 140 , alkyl; or L 3 and L 4 and X can independently be C 1 -C 140 (for example C 1 , C 2 , C 3 , C 4 , C 5 , C 6 , C 7 , C 8 , C 9 or C 10 ; C 1 -C 10 , -C 20 , -C 30 , -C 40 , -C 50 -C 60 , -C 70 , -C 80 , -C 90 , -C 100 , -C 110 , -C 120 , -C 130 or -C 140 ), cycloaliphatic, heterocyclic, aromatic, aryl, alkylaryl, arylalkyl, oxyalkylene radicals; or a polyalkylene radical optionally interrupted by one or more, preferably one, oxygen, nitrogen or sulphur atoms, functional groups as well as saturated or unsaturated cyclic moiety; “G 4 ” and “G 5 ” are cationic moieties and can be same or different, and at least one of them is a biguanidine moiety or carbamoylguanidine, and the other moiety may be biguanidine or carbamoylguanidine or amine; and cationic moieties G 4 and G 5 do not contain single guanidine groups. The entry-promoting agent may comprise homogeneous or heterogeneous mixture of one or more of agents arising from formulae 1 a and b, for example polyhexamethylene biguanide (PHMB), polyhexamethylene monoguanide (PHMG), polyethylene biguanide (PEB), polytetramethylene biguanide (PTMB), polyethylene hexamethylene biguanide (PEHMB), polymethylene biguanides (PMB), poly(allylbiguanidnio-co-allylamine), poly(N-vinylbiguanide), polyallybiguanide.